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The Nutritive Value of Cottonseed for Chicks as Affected by Methods of Processing and Content of Pigment Glands
T h e Nutritive Value of Cottonseed for Chicks as Affected by Methods of Processing and Content of Pigment Glands C. H. BOATNER, A. M. ALTSCHUL, G. W. IRVING, JR. 1 AND E. F. POLLARD Southern Regional Research Laboratory? New Orleans, Louisiana AND
H . C . SCHAEFER The Ralston Purina Company, St. Louis, Missouri (Received for publication October 29, 1947)
O I N C E cottonseed meal was one of the ^ first protein concentrates to be fed to to livestock on a large scale, numerous investigations were published relative to its nutritive value before the importance of balanced diets, and of vitamins, and other essential nutritional factors was recognized. Proper evaluation of cottonseed as a protein feed is rendered difficult by the mass of confusing and contradictory data which accumulated during the period of these early nutritional investigations. Numerous recent investigations have established the high nutritive value of hydraulic- and screw-pressed cottonseed meals produced by expression of the oil from cooked cottonseed. These cottonseed meals represent one of the most important sources of concentrated protein presently available to livestock feeders. The nutritive value of uncooked cottonseed has been established for beef cattle (Clark, 1 Present address, Division of Biologically Active Compounds, BAIC, Agricultural Research Center, Beltsville, Maryland. 2 One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration. U. S. Department of Agriculture.
1936), but for other livestock it is generally believed (Olcott, 1941, 1942) that cooking is essential in order to obtain cottonseed meal which is a satisfactory and safe livestock feed. Until recently, this has been a somewhat academic problem since cottonseed has always been processed in this country by expression of the oil from cooked seed. However, the question of the suitability of uncooked cottonseed as a livestock feed is now of practical importance, as well as some concern, because of the recent application of solvent extraction methods for processing cottonseed. Cooking of cottonseed has been reported (Olcott, 1941) to improve neither the yield nor the quality of the solvent-extracted oil. . The deleterious physiological effects of uncooked or partially cooked cottonseed have generally been attributed to the presence of gossypol, a yellow polyphenolic pigment which occurs in the cottonseed in concentrations as high as three percent of the weight of the kernel. Withers and Carruth (1915) were the first to observe the correlation between the decrease in the amount of gossypol which could be extracted with diethyl ether, and
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BOATNER, ALTSCHUL, IRVING, POLLARD AND SCHAEFER
the improved nutritive value of the cooked seed. They also found that extraction of uncooked cottonseed with diethyl ether rendered the meal non-toxic when fed to rats and guinea pigs, whereas the diethyl ether extract was toxic to these animals. These and related observations led to the bound gossypol theory (Withers and Carruth, 1915, Carruth, 1917, Clark, 1928 and 1928b) of gossypol detoxification. According to this theory, gossypol was assumed to be solely responsible for the toxicity of raw cottonseed, and it was assumed, further, that the gossypol became inactivated during cooking of cottonseed as a result of its reaction with the protein in the seed to form so-called bound gossypol. The observation of Olcott (1941) that meal produced by extraction of uncooked cottonseed with petroleum naphtha was toxic to rats appears to lend additional support to this theory since extraction with petroleum naptha removes only a small fraction of the total gossypol present in the cottonseed kernel. On the other hand, the nutritional investigations of Gallup (1927, 1928), Lyman, Holland and Hale (1944), Sewell (1943) and Sewell and Turney (1946) have shown very poor correlation between the content oifree gossypol in meals obtained from cooked cottonseed, and their nutritive value for different experimental animals. Gallup (1928) concluded from his observations that other components of cooked cottonseed in addition to free and bound gossypol affect its nutritional value. It was recently shown (Boatner and Hall, 1946; Boatner, Hall, Rollins, and Castillon, 1947) that the pigment glands of cottonseed, which are distinct morphological structures peculiar to the cottonseed kernel and to the seed of a very few closely related genera, and which contain
most of the pigments of the kernel, are resistant to the action of hydrocarbon solvents, but are slowly ruptured during contact with diethyl ether. The pigment glands separated from seed of different varieties of Gossypium hirsutum, the species of cottonseed grown in largest quantity in the United States, have been found (Boatner, Hall, O'Connor, and Castillon, 1947) to be fairly uniform with respect to their content of pigments. Gossypol constitutes from 39 to 49 percent, and gossypurpurin (Boatner, 1944) from one to three percent of the weight of the glands. These were the only pigments which could be detected in the samples of isolated pigment glands which have been examined to date. Ethereal extracts of pigment glands represent approximately one half of the total weight of the glands, and gossypol and gossypurpurin constitute 80 to 90 percent of the weight of the material extracted from the glands by diethyl ether. In view of the somewhat contradictory reports concerning the toxicity of gossypol in cottonseed, it seemed possible that the high nutritive value of the meal produced by extraction of uncooked cottonseed with diethyl ether might be the result of the removal of components of the pigment glands other than gossypol, and that conversely, the toxicity of the meal produced by petroleum naptha extraction of uncooked cottonseed might result from the failure of the latter solvent to remove these toxic components of the pigment glands. The semi-pilot plant development (Vix, Spadaro, Westbrook, Crovetto, Pollard, and Gastrock, 1947), of the flotation process (Boatner and Hall, 1946) for the separation of intact pigment glands from the oil and protein tissue of the cottonseed kernel has made available pigment glands and gland-free cottonseed
T H E NUTRITIVE VALUE OF COTTONSEED FOR CHICKS
flour in quantities sufiicient for determining their physiological properties. Withers and Carruth (1915) noted that hydraulic-pressed cottonseed meal obtained from pre-cooked seed was inferior to the meal produced by extraction of uncooked cottonseed with diethyl ether when these meals were used in unsupplemented diets. Olcott and Fontaine (1941) also found that the protein nutritional value of meal obtained by extraction of uncooked cottonseed with diethyl ether decreased in proportion to the length of time of subsequent cooking of the extracted meal. It seemed probable therefore that gland-free cottonseed flours produced from uncooked cottonseed and subjected to only mild heating during processing should be superior in nutritive value to hydraulic-pressed cottonseed meal. There follows the report of an investigation of the effect on chick growth of various cottonseed products compared with that obtained on a basal diet containing 13 persent of screw-pressed soybean meal as the source of vegetable protein. The following cottonseed products were used in the experimental feeding tests; (1) hydraulic-pressed cottonseed meal, (2) hydraulic-pressed cottonseed meal extracted with commercial hexane, (3) uncooked cottonseed extracted with commercial hexane, (4) uncooked cottonseed extracted with diethyl ether, (5) the preceding solvent-extracted meals subsequently subjected to heat, (6) gland-free cottonseed flour, (7) soybean meal plus gossypol, and (8) soybean meal plus cottonseed pigment glands. In the case of the cottonseed meals, the experimental diets were prepared by substituting equal quantities of the cottonseed products in place of the soybean meal in the standard basal diets. Gossypol and separated pig-
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ment glands were mixed in measured amounts with the standard soybean diet. These diets were fed under comparable conditions to lots of twenty to thirty chicks each for a period of six weeks. EXPERIMENTAL PROCEDURE
The. different series of experiments reported here were carried out over a period of three years and the soybean and cottonseed products were therefore produced from seed grown during three seasons. Preparation of cottonseed products The cottonseed products included in the diets for any one group of parallel feeding experiments were prepared from a single lot of prime seed, except the commercial hydraulic-pressed cottonseed meal which was used for comparative purposes in the diet of one lot of chicks. Hydraulic-pressed meals.—An ExportType Model of French hydraulic box press was used in preparing the cottonseed meals. One pound of water was added to
each forty-pound charge of flaked meats before cooking. The meats were cooked for forty minutes (20 minutes in each of the two stacks of the cooker) to a final temperature of 120°C. (248°F.). Oil was expressed from the cooked meats under a pressure of 4,000 Ib/sq. in. on the ram (1,760 Ib./sq. in. on the plates) for fifteen minutes. The sample of commercial hydraulicpressed cottonseed meal represented a random selection of standard prime quality cake which was produced by a commercial processor in Mississippi. Solvent-extracted cottonseed.—The meats used for preparing the solvent-extracted cottonseed meal and gland-free cottonseed flour were cracked and flaked on rolls set with clearances of 0.025 and 0.0015 in.,
respectively.
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BOATNER, ALTSCHUL, IRVING, POLLARD AND SCHAEFER
Hexane-extracted cottonseed was prepared by extracting flaked seed in a single cell, batch extractor with commercial hexane.3 The extraction was carried out for six hours, and the solvent in contact with the flakes was maintained at a maximum temperature of 30°C. (85°F.). The solvent-extracted meal was freed of solvent by air-drying. Solvent-extracted press cake was prepared by extracting ground hydraulicpressed cake with commercial bexane in the same extractor and under the same conditions as described above. Diethyl ether-extracted cottonseed meal used for the first feeding experiment was prepared in the same equipment and under the same conditions employed with hexane. Commercial grade diethyl ether was used. The diethyl ether-extracted cottonseed meal used in the last feeding experiment was prepared in a battery of Soxhlet extractors. Commercial grade diethyl ether was refluxed through the flaked meats for three hours. The ether was then allowed to remain in contact with the seed in the extractor overnight at room temperature. Refluxing of the ether was then continued for another three hours after which the meal was freed of residual solvent by airdrying. Gland-free cottonseed flour.—This product was prepared by the semi-pilot plant development (Vix, Spadaro, Westbrook, Crovetto, Pollard, and Gastrock, 1947) of the flotation process (Boatner and Hall, 1946) using a mixture of commercial hexane and tetrachlorethylene of density 1.378 g./cc. The moisture content of the flaked seed was reduced to approximately five percent by heating at 51.5°C. (125°F.) 3 The commercial hexane used throughout this investigation had a boiling range of 63°-70°C. (146°158°F.).
for two hours in a drying oven before separating the oil and glands by flotation. The dried flakes were disintegrated in the solvent mixture, most of the pigment glands separated by flotation, and the residual meal was re-processed to remove any remaining pigment glands. The glandfree cottonseed flour was washed on a filter cloth four times with commercial hexane. The flour was then de-solventized in a vacuum tray dryer. One sample of gland-free flour was dried at a maximum temperature of 47°C. (117°F.) and the other at a maximum temperature of 99°C. (210°F.). Cottonseed pigment glands.—The glands were obtained from flaked cottonseed by the flotation process carried out as described above. The concentrated preparation of glands obtained in the first flotation step consisted of a slurry of pigment glands, fine meal, and solvent. Portions of approximately 300 g. of this slurry were suspended with 300 g. of silica (300 mesh) in a solvent mixture having a density of 1.378 g./cc. and the suspension agitated vigorously for forty-five minutes. The layer of pigment glands which rose to the surface of the solvent mixture on standing was removed, washed several times with commercial hexane, screened on a 230mesh sieve in order to remove fine particles of meal, and dried in a vacuum desiccator at room temperature. Gossypol.—Gossypol was prepared from an ethereal extract of cottonseed according to the procedure described by Boatner, O'Connor, Samuels, and Curet (1947). Crude gossypol was separated from the ethereal -extract by extraction with aqueous alkali, and the alkaline extract acidified and re-extracted with diethyl ether. Gossypol-acetic acid was precipitated from the last mentioned extract, after which it was hydrolyzed by suspending it in boiling water for one hour.
T H E NUTRITIVE VALUE OF COTTONSEED FOR CHICKS
Impurities were removed by digesting the crude gossypol with toluene at room temperature. The purity of the gossypol was established by application of the antimony trichloride-spectrophotometric test for gossypol (Boatner, Caravella, and lOyame, 1944). Determination of the pigment contents of the cottonseed products.—Chloroform extracts of meal and gland fractions were prepared by equilibration of weighed samples with measured volumes of chloroform for twenty-four hours at 3.3°C. (38°F.) in the absence of light (Boatner, Hall, O'Connor and Castillon, 1947). Aqueous ethanol extracts were prepared by adding 30 ml. of aqueous ethanol (30 percent ethanol by weight) to weighed samples of glands or meal. The suspension was allowed to stand at room temperature with occasional shaking for ten to thirty minute.s, after which 70 ml. of aqueous ethanol (72 percent ethanol by weight) was added to the suspension. The suspension was thoroughly agitated and then centrifuged, and aliquots of the supernatant were removed for transfer of the dissolved material to chloroform (Boatner, Hall, O'Connor, and Castillon, 1947). The concentration of gossypol in the chloroform extracts and in chloroform solutions of the ethanol extracts was determined by application of the antimony trichloride-spectrophotometric method for gossypol (Boatner, Caravella, and Kyame, 1944). The concentration of gossyfulvin (Boatner, Caravella, Samuels 1944; Boatner, O'Connor, Samuels, and Curet, 1947) in the extracts was estimated on the basis of the increase in the extinction coefficient at 520m/i of the antimony trichloride reaction product obtained by treating the extract with concentrated hydrochloric acid, before adding antimony trichloride. The concentration of gossypurpurin
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(Boatner 1944; Boatner, Hall, O'Connor, Castillon, and Curet, 1947) in the samples of meal and glands was determined on the basis of the specific extinction coefficients of the chloroform extracts at 565 to 566m/i. The percentage of gossypurpurin in each sample was calculated by means of the equation ( E ^ m . extract/Eif m . gossypurpurin X100) where E i ^ . extract is the specific extinction coefficient of the chloroform extract at 565 to 566mju, and El^°m. gossypurpurin is the specific extinction coefficient of pure gossypurpurin at the same wavelength (Boatner, Hall, O'Connor, Castillon, and Curet, 1947). Preparation of screw-pressed soybean meal The soybean meal used for the feeding experiments consisted of a standard, commercial grade, screw-pressed meal prepared by the following procedure. Soybeans were cracked to give a product in which 55 percent was held on an 8-mesh screen and 30.5 percent on a 10-mesh screen. The cracked beans were dried to a moisture content of 1.4 percent and heated to a temperature of 137°C- (278°F.) before entering the presses. The oil was pressed from the beans under a pressure of 12,000 lb./sq. in. within the press. The beans remained in the press for about two minutes, and the meal reached a final temperature of approximately 149°C. (300°F.). Preparation of diets All of the ingredients used in the basal ration common to all of the diets were combined in a mixture which constituted 87 percent of the total diet. The ingredients were selected from a common source and represented standard ingredients used for poultry starting feeds. A mixture of wheat bran, wheat middling,
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BOATNER, ALTSCHUL, IRVING, POLLARD AND SCHAEFER
ground oats, meat scrap, fish meal, dehydrated alfalfa, calcium carbonate, corn gluten meal, riboflavin, sodium chloride, and vitamin D 3 constituted 42.3 percent, and yellow corn 57.7 percent of the basal ration. Eighty-seven parts of this basal mixture were mixed thoroughly with 13 parts of soybean or cottonseed meal. The average protein content of the final experimental diets was 22 percent. Therefore, 13 percent of soybean or cottonseed meal containing 43 percent protein contributed approximately 25 percent of the total protein of the diet. Portions of gossypol or pigment glands to be added to the soybean basal diet were accurately weighed on an analytical balance. They were pre-mixed with part of the basal diet, and this mixture was then thoroughly incorporated into the whole of the experimental ration. Feeding experiments The chicks used in the feeding experiments were hatched at the Purina Research Farm. The laying hens received rations known to assure normal offspring. The chicks were housed at the Biological Laboratory of the Ralston Purina Company in commercial type battery brooders, heated electrically, and equipped with wire floors. The room in which the chicks were housed was maintained at a temperature of 24° to 27°C. (75° to 80°F.) and a relative humidity of 45 to 55 percent. The batteries were all arranged vertically so that some lots of chicks were at higher levels than others. In previous work it had been observed that it made little or no difference as far as growth is concerned, whether the chicks were on the lower or upper tiers. The feed for the chicks was weighed, and the chicks had access to feed at all times. The feed hoppers and water containers
were attached to the side of the brooder in such a way that the birds could eat or drink at will. The chicks were weighed as a group at the beginning of the experiment, and individually at the end of the test. The weights were recorded in grams, using a balance calibrated to weigh accurately to one-half gram. The amount of feed consumed was obtained by the difference in weight of the feed placed in the hoppers and the unconsumed portions. Comparison 'of hydraulic-pressed cottonseed and screw-pressed soybean meals.—• Hydraulic-pressed cottonseed produced in the pilot plant was substituted for screwpressed soybean meal in two basal diets, and the soybean and cottonseed meal diets were fed ad libitum for six weeks to four parallel lots of twenty each White Plymouth Rock chicks. The average gains in weight of the two lots of chicks fed cottonseed meal were 433 g. and 324 g., respectively, which was significantly less than the average gains of 486 g. and 435 g., respectively, made by the two lots which were fed the standard soybean meal diets. Comparison of uncooked, hexane-extracted cottonseed and screw-pressed soybean meal.—When cottonseed meal produced in the pilot plant by extraction of flaked meats with commercial hexane was substituted for screw-pressed soybean meal in the same two basal diets as were used in the preceding series, the average gains of the chicks were very much less than those of the chicks in the preceding series which were fed diets containing hydraulic-pressed cottonseed meal. The average gains of two lots of twenty chicks each on diets containing uncooked, hexane-extracted cottonseed were 277 g. and 256 g., respectively, whereas the average gains made by two control lots on standard diets containing soybean meal were 401 g. and 395 g., respectively.
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T H E NUTRITIVE VALUE OF COTTONSEED FOR CHICKS
Comparison of hydraulic-pressed cottonseed meal; hydraulic-pressed cottonseed meal extracted with hexane; uncooked hexane-extracted cottonseed; soybean meal; and soybean meal plus gossypol.—In order to eliminate variations which might result from differences in composition of the seed, this series, and each succeeding series of feeding experiments, was carried
of the average gain in weight of the control lot on the standard soybean diet. From these data it can be seen that both samples of hydraulic-pressed cottonseed meal supported gains approximately equal to those of the control lot. Although the slightly lower gains made with hydraulicpressed cottonseed meal which had been extracted with hexane are not readily
TABLE 1.—Effect of gossypol and various hydratdic-pressed cottonseed meals on chick growth Composition of diets 1 Protein, % Riboflavin, p.p.m. Gossypol, %
Ration 1 21.85 5.7 None
Ration 2 20.71 4.6
Results of feeding tests 6 Av. starting weight, g. Av. wt. at 6 weeks, g. Av. gain, g. Livability, % Av. gain, % of control
36.0 459.9 423.9 100 100
35.8 458.9 423.1 100 100
2
Ration 3 21.31 5.6 none 3
Ration 4 21.54 5.4 0.13
Ration 5 21.66 5.5
35.9 449.1 413.2 100 97.5
35.7 385.1 349.4 100 82.5
36.0 418.3 382.3 100 90.0
2
Ration 6 21.45 5.7 0.13 4 35.8 163.7 127.9 100 30.0
1 The diets contained 13 percent of the following: screw-pressed soybean meal in Ration 1 (control); hydraulic-pressed cottonseed meal (commercial) in Ration 2; hydraulic-pressed cottonseed meal (pilot plant) in Ration 3; screw-pressed cottonseed meal plus gossypol (0.13 percent) in Ration 4; hydraulicpressed cottonseed meal (pilot plant), extracted with hexane in Ration 5; and uncooked, hexane-extracted cottonseed in Ration 6. Other components of these diets: moisture, 9.29 percent; fat, 3.78 percent; fiber, 5.27 percent; N.F.E., 54.51 percent; ash, 5.33 percent; calcium, 1.26 percent; phosphorus, 0.76 percent; manganese, 59 p.p.m.; carotene, 10.10 p.p.m.; xanthophyll, 15.80 p.p.m.; thiamin, 2.90 p.p.m.; pantothenic acid, 17.00 p.p.m.; niacin, 3.50 p.p.m. 2 Not determined. 3 No gossypol, 0.04 percent gossyfulvin. 4 The gossypol content of the extracted meal was estimated on the basis of that of the original meats, assuming no gossypol was extracted by commercial hexane. 8 The rations were fed for six weeks to lots of 30 white leghorn chicks, one day old at beginning of experiment.
out with products prepared from the same lot of cottonseed. Since essentially similar results had been obtained with the two basal diets, only one basal diet was used in this experiment and subsequent experiments. The composition of the diets and gains in weight and other pertinent data for the chicks used in this series of feeding experiments are given in Table 1. In order to facilitate comparison of results obtained with the different diets, the average gain in weight of each lot of chicks was calculated as the percentage
explainable, they eliminate the possibility that the very poor gains made with uncooked, hexane-extracted cottonseed resulted from the presence of residual solvent or alteration of the components of the uncooked seed by the solvent. Finally, although addition of gossypol to the standard soybean diet caused definite retardation in growth, the deleterious effect of the uncooked, hexane-extracted cottonseed Was very much greater than that caused by gossypol alone. The deleterious effect of the uncooked seed appears, therefore, to be attributable to
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BOATNER, ALTSCHUL, IRVING, POLLARD AND SCHAEFER
some component of the seed in addition to gossypol, and the superior nutritional value of hydraulic-pressed cottonseed meal appears to be the result of partial or complete destruction during cooking of the physiologically active components of the raw seed or to their removal during subsequent expression of the oil. The superficial physical condition of typical chicks to which the above-described diets were fed may be seen in Figure 1. It is apparent that the physical condition of the chicks which received gossypol in the basal (soybean) diet is inferior to that of the chicks on the control diet (soybean) but it is very much better than that of the chicks fed TABLE 2.—Effect
Composition of diets 1 Moisture, % Protein, % Fat, % Crude fiber, % Ash, % N.F.E., % Calcium, % Phosphorus, % Manganese, p.p.m. Carotene, p.p.m. Xanthophyll, p.p.m. Thiamin, p.p.m. Niacin, p.p.m. Riboflavin,p.p.m. Gossypol, % Gossypurpurin, %
Ration 1 8.07 24.71 5.17 6.70 6.71 48.64 1.48 0.80 90.2 8.0 15.8 3.89 37.5 5.85 none none
Results of feeding tests1! Av. starting weight, g. 37.5 Av. weight at 6 wks., g. 501.2 Av.gain.g. 463.7 Av. feed consumption, g. 1057.7 Av. g. feed per g. gain 2.28 Livability, % 96 Av. gain, % of control 100
diets containing uncooked hexane-extracted cottonseed. Comparison of uncooked, diethyl etherextracted cottonseed; uncooked, hexaneextracted cottonseed; solvent-extracted meals after cooking; hydraulic-pressed cottonseed; and soybean meal.—The composition of the diets, gains in weight of the different lots of chicks, and other pertinent data for this series of feeding tests are shown in Table 2. Better growth was obtained with the diet containing hydraulic-pressed cottonseed meal than was obtained with the soybean meal. Extraction of the hydraulic-pressed cottonseed meal with commercial hexane reduced its nutritional
of various hydraulic-pressed and solvent-extracted cottonseed meals on chick growth
Ration 2 8.67 25.04 5.68 6.72 6.68 46.52 1.49 0.87 87.2 8.5 16.0 5.40 42.3 5.25 0.07 0.0081
Ration Ration 3 4 8.82 7.88 26.00 25.90 5.70 4.93 6.56 6.57 6.90 6.82 46.96 46.96 1.46 1.44 0.95 0.93 84.0 90.8 7.8 8.1 15.7 16.7 6.26 5.84 39.4 44.6 5.39 5.32 0.03 0.46 0.0076 < 0.033
Ration Ration 5 6 9.08 8.66 25.76 26.02 4.92 5.67 6.57 6.48 6.86 6.64 45.98 46.81 1.47 1.59 0.92 0.91 98.0 90.1 8.4 8.2 15.6 17.0 5.94 5.70 40.7 41.3 5.14 4.81 0.30 0.01 0.036 0.0020
Ration Ration 7 8 8.58 8.49 26.44 26.21 4.74 5.67 7.21 6.58 6.90 7.09 46.13 45.96 1.57 1.55 0.91 0.90 81.1 85.0 7.4 7.2 15.0 15.1 5.83 5.87 41.3 39.9 4.76 4.46 0.01 0.01 0.0015 0.00045
37.6 523.9 486.3
37.7 500.8 463.1
37.7 288.0 240.3
37.8 324.3 286.5
37.5 436.3 398.8
37.3 455.8 418.5
37.7 457.2 419.5
1037.4 2.13 100 105
980.9 2.12 100 100
819.2 3.41 100 52
895.7 3.13 100 62
897.7 2.25 100 86
1020.8 2.44 100 90
950.5 2.27 100 91
1 The diets contained 13 percent of the following: screw-pressed soybean meal in Ration 1 (control); hydraulic-pressed cottonseed meal in Ration 2; hydraulic-pressed cottonseed meal extracted with hexane in Ration 3; uncooked, hexane-extracted cottonseed in Ration 4; hexane-extracted cottonseed, wet-cooked 15 minutes in Ration 5; uncooked, diethyl ether-extracted cottonseed in Ration 6; diethyl ether-extracted cottonseed dry-cooked 16 hours in Ration 7; and diethyl ether-extracted cottonseed, wet-cooked 15 minutes in Ration 8. 2 The rations were fed for six weeks to lots of 25 White Plymouth Rock chicks, one day old at beginning of experiment.
T H E NUTRITIVE VALUE OF COTTONSEED EOR CHICKS
323
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FIG. 1. Appearance of typical 6-week old chicks from parallel lots fed rations containing: (a) soybean meal (control), (b) commercially hydraulic-pressed cottonseed meal, (c) soybean meal plus gossypol, (d) hydraulicpressed cottonseed meal (Pilot plant), (e) hydraulic-pressed cottonseed meal extracted with hexane, (f) uncooked cottonseed extracted with commercial hexane.
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BOATNER, ALTSCHUL, IRVING, POLLARD AND SCHAEFER
value to that of the soybean meal. The average gain in weight of chicks fed uncooked, hexane-extracted cottonseed was very poor, and heating of the extracted meal for 15 minutes in the presence of moisture resulted in only slight improvement in its nutritional value. The meal obtained by extraction of uncooked cottonseeed with diethyl ether produced better growth than the hexane-extracted cottonseed, but Jess gain than was obtained with the hydraulic-pressed cottonseed meal. Cooking of the diethyl etherextracted seed in the presence of moisture for fifteen minutes at 116°C. increased its nutritional value to about the same extent as heating it in the absence of moisture for sixteen hours at -70° to 80°C.
cottonseed and both of the gland-free cottonseed flours supported somewhat better growth than the screw-pressed soybean meal. All three of these cottonseed products contained relatively insignificant amounts of gossypol and no gossypurpurin. The diethyl ether-extracted cottonseed contained more gossypol, but supported slightly better growth, than did either of the gland-free cottonseed flours. The growth of chicks fed hexaneextracted cottonseed was somewhat superior to that of the chicks fed the standard diet to which cottonseed pigment glands had been added. The diet of the former lot of chicks contained slightly more gossypol and less gossypurpurin than the diet which contained added cottonseed pigment glands.
A poor correlation was found between the nutritional value of the different cottonseed meals and their content of extractable gossypol and gossypurpurin. Although the hydraulic-pressed cottonseed meal produced better gains than did the meal obtained by extraction of uncooked cottonseed with diethyl ether, the extracted seed contained less extractable gossypol and gossypurpurin than did the hydraulic-pressed meal. The increase in the nutritional value resulting from cooking the extracted seed was greater than might have been predicted on the basis of the slight decrease which occurred in the extractable pigments as the result of cooking. Comparison of gland-free cottonseed flour; uncooked diethyl ether-extracted cottonseed; uncooked hexane-extracted cottonseed; soybean meal; and soybean meal plus pigment glands.—The composition of the diets, gains in weight of the chicks during six weeks' feeding of the different diets, and other pertinent data for this series of feeding tests are shown in Table 3. The uncooked, diethyl ether-extracted
Histological examination4 of liver and kidney sections showed no detectable differences between those from the control lot of chicks and those from the lot fed pigment glands, except for a slightly more intense nuclear staining of the cells of the liver in the case of the chicks fed pigment glands. This condition did not appear to represent an inflammatory change and was of no apparent pathological significance, but indicated only some special affinity of these particular nuclear remains for hematoxylin stain. The weekly growth curves of chicks on the different diets are shown in Figure 2. Since the growth curve of chicks on gland-free cottonseed flour de-solventized at a maximum temperature of 47° C. (Ration 3) was almost exactly the same as that of chicks on the other gland-free cottonseed flour (Ration 4), it is not shown. Comparison of the growth curves show's that the diethyl ether-extracted 1 Performed by the Gradwohl Laboratories, St. Louis, Missouri.
T H E NUTRITIVE VALUE OF COTTONSEED FOR CHICKS
TABLE 3.—Effect
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of various solvent-extracted cottonseed meals, gland-free cottonseed flours, and cottonseed pigment glands on chick growth Ration 5 8.67 20.52 4.00 5.92 7.07 53.82 1.66 0.66 84.00 12.40 18.50 6.00 0.244 0.0075
Ration 6 9.21 20.52 3.95 5.59 7.01 53.67 1.65 0.66 90.00 12.00 18.20 6.50 none none
Composition of diets 1 Moisture, % Protein, % Fat, % Crude fiber, % Ash, % N.F.E., % Calcium, % Phosphorus, % Manganese, p.p.m. Carotene, p.p.m. Xanthophyll, p.p.m. Riboflavin, p.p.m. Gossypol, % Gossypurpurin, %
Ration 1 9.02 21.82 3.46 5.55 7.19 52.96 1.63 0.75 74.00 12.20 16.50 6.00 0.250 0.0052
Ration 2 9.87 21.15 3.17 5.47 7.28 53.06 1.68 0.75 80.00 12.20 16.00 6.80 0.0032 none
Ration 3 9.46 21.73 3.10 3.76 7.21 54.74 1.70 0.76 73.00 11.70 15.80 6.00 0.00078 none
Results of feeding tests 2 Av. st. weight—g. Av. wt.—1st wk., g. Av. wt.—2nd wk., g. Av. wt.—3rd wk., g. Av. wt.—4th wk., g. Av. wt.—5th wk., g. Av. wt.—6th wk., g. Av. gain, g.
35.7 58.0 72.9 89.7 114.4 144.2 170.9 135.2
35.7 •75.5 131.0 207.3 296.5 390.5 508.5 472.8
35.7 70.8 124.5 200.0 282.6 379.9 485.1 449.4
35.7 72.3 123.0 197.3 287.8 392.7 488.1 452.4
35.7 62.3 78.8 91.7 103.2 122.0 143.8 108.1
35.7 70.5 117.3 190.5 265.5 356.4 454.0 418.3
61.5 107.0 172.0 206.8 291.0 311.0 1149.3 2.43 100 good 113
72.0 117.8 179.5 232.9 310.0 356.8 1269.0 2.82 95 good 108
65.8 107.0 162.5 211.3 299.0 316.0 1161.6 2.57 100 good 108
72.0 78.5 108.4 149.4 217.5 164.8 790.6 7.31 75 poor 26
68.8 101.0 162.0 207.5 276.0 299.0 1114.3 2.66 100 good 100
Av. feed cons.—1st wk., g. 56.5 Av. feed cons.—2nd wk., g. 69.5 Av. feed cons.—3rd wk., g. 105.2 Av. feed cons.—4th wk., g. 152.2 Av. feed cons.—5th wk., g. 246.5 Av. feed cons.—6th wk., g. 322.9 Av. total feed cons., g. 952.9 Av. g. feed per g. gain 7.05 Livability, % 85 Condition of chicks poor Av. gain, % of control 32
Ration 4 8.44 22.12 3.55 3.16 7.26 55.47 1.68 0.78 84.00 14.70 16.00 6.00 0.00078 none
1 The rations contained 13 percent of the following: uncooked, hexane-extracted cottonseed in Ration 1; uncooked, diethyl ether-extracted cottonseed in Ration 2; gland-free cottonseed flour, desolventized at maximum temperature of 47°C. in ration 3; gland-free cottonseed flour desolventized at maximum temperature of 99°C. in Ration 4; screw-pressed soybean meal plus cottonseed pigment glands (0.65 percent) in Ration 5; and screw-pressed soybean meal in Ration 6 (control). 2 The rations were fed for six weeks to lots of 20 White Plymouth Rock chicks, one day old at beginning of experiment.
cottonseed and the gland-free cottonseed flour initially produced slightly better gains than did the soybean meal, and that they produced increasingly improved gains throughout the six-week period. The hexane-extracted cottonseed and soybean meal plus cottonseed pigment glands caused retardation in growth from the beginning of the experiment, and their deleterious effect became more pronounced as the feeding was continued.
DISCUSSION
It may be concluded from these experiments that all of the components of the cottonseed kernel which are injurious to chicks are segregrated- in the pigment glands, and that uncooked cottonseed can be freed of these objectionable components by exhaustive extraction with diethyl.ether or by mechanical removal of the pigment glands. Furthermore, since cottonseed pigment glands added to
326
BOATNER, ALTSCHXJL, IRVING, POLLARD AND SCHAEFER
J I
I 2
I »
I »
I »
A O E - WEEKS
FIG. 2. Growth curves of chicks on diets containing (1) uncooked, hexane-extracted cottonseed, (2) uncooked, diethyl ether-extracted cottonseed, (3) gland-free cottonseed flour, desolventized at maximum temperature of 47°C. (same as 4), (4) glandfree cottonseed flour, desolventized at maximum temperature of 99°C, (5) screw-pressed soybean meal, plus cottonseed pigment glands, (6) screwpressed soybean meal (control).
a diet containing no other cottonseed product produced approximately the same retardation in the growth of chicks as uncooked hexane-extracted cottonseed, it can be concluded that the deleterious effects of the pigment glands are not dependent upon their interaction with either the protein or the other extraglandular components of the cottonseed. Gossypol has been shown (Boatner, Hall, O'Connor, and Castillon, 1947) to be the principal component of cottonseed pigment glands, and gossypurpurin, a derivative of gossypol, is the only other extractable pigment which was found in detectable amounts in the cottonseed
•
pigment glands used in the feeding experiments and in other samples of cottonseed pigment glands which have been examined (Btoatner, Hall, O'Connor, and Castillon, 1947). The poor correlation which was observed between the nutritional values of the different cottonseed products and their relative contents of gossypol and gossypurpurin, coupled with the very slightly deleterious effect of gossypol added to the diet, indicates that components of the glands other than these pigments are responsible for the deleterious effect on chicks of cottonseed pigment glands. It has been shown (Boatner, Hall, O'Connor, and Castillon, 1947) that gossypol and its antimony trichloride reaction product suffer no alteration in their visible and ultraviolet absorption spectra during isolation and subsequent purification by the same methods as were employed in the preparation of the gossypol used in these experiments. In addition, the behavior of cottonseed pigment glands with water and various organic-solvents (Boatner, Hall, Rollins, and Castillon, 1947) indicates that the extractable gossypol and gossypurpurin of the glands occur as a gelatinous suspension rather than in chemical combination with other components of the glands. The superiority of the hydiaulie-pressed cottonseed meal to uncooked, hexaneextracted cottonseed can be attributed to inactivation of the toxic factors of the pigment glands during cooking of the seed, or to their removal during expression of the oil, or to both. Since all of the hydraulic-pressed cottonseed meals prepared in the pilot plant were processed under practically identical conditions, the slight variations in their nutritional values appear to be attributable to differences in the composition of the
T H E NUTRITIVE VALUE OF COTTONSEED FOR CHICKS
different lots of cottonseed. It is noteworthy that the hydraulic-pressed meals were precooked before pressing for only forty minutes. The improvement in the nutritional value which resulted from heating the meal from solvent-extracted seed apparently can be attributed to partial inactivation of the residual deleterious physiological factors of the pigment glands in the solvent-extracted seed. Heating the gland-free cottonseed flour during de-solventization had no appreciable effect on its nutritive value. SUMMARY An investigation is reported of the effect on the growth of chicks of uncooked cottonseed extracted with hexane, uncooked cottonseed extracted with diethyl ether, the foregoing solvent-extracted meals subsequently heated, hydraulicpressed cottonseed meal,hydraulic-press"d cottonseed meal extracted with hexane, gland-free cottonseed flour, gossypol, and cottonseed pigment glands. The cottonseed meals were substituted for soybean meal in a basal diet containing 13% of screw-pressed soybean meal as the source of vegetable protein, and the gossypol and pigment glands were added in measured amounts to the basal soybean meal diet. The basal soybean meal diet and the experimental cottonseed diets were fed to parallel lots of 20 to 30 chicks each for a period of six weeks. Gland-free cottonseed flour; uncooked, diethyl ether-extracted cottonseed; and hydraulic-pressed cottonseed meal supported excellent growth, whereas markedly inferior growth resulted when the experimental diets containing uncooked, hexane-extracted cottonseed or pigment glands were fed to chicks. These results showed that all of the physiologically deleterious components of cottonseed are segregated in the pigment glands.
327
Pure gossypol added to the diet produced relatively little retardation in the growth of chicks, and a poor correlation was found between the nutritional values of the various cottonseed products and their contents of gossypol and gossypurpurin. ACKNOWLEDGMENT The authors wish to acknowledge with appreciation the assistance in this investigation which was rendered by L. E. Castillon, M. C. Curet, M. E. Curet, T. D. Fontaine, E. A. Gastrock, C. M. Hall, M. L. Karon, E. L. D'Aquin, W. F. Guilbeau, E. J. McCourtney, C. H. Murphy, R. M. Persell, J. Pominski, C S. Samuels, J. J. Spadaro, and H. L. E. Vix of the Southern Regional Research Laboratory, W. T. Chilson of the Ralston Purina Company and H. Patrick formerly of the Ralston Purina Company. REFERENCES
Boatner, C. H., 1944. The pigments of cottonseed. Oil & Soap 21:10-15. Boatner, C. H., M. Caravella, and L. Kyame, 1944. Quantitative determination of extractable gossypol in cottonseed and cottonseed meal. Ind. Eng. Chem., Anal. Ed. 16: 566-572. Boatner, C. H., M. Caravella and C. S. Samuels, 1944. An orange-colored pigment of cottonseed. J. Am. Chem. Soc. 66:838. Boatner, C. H., and C. M. Hall, 1946. The pigment glands of cottonseed. I. Behavior of the glands toward organic solvents. Oil & Soap 22: 123-128. Boatner, C. H., C. M. Hall, R. T. O'Connor, and L. E. Castillon, 1947. The pigment glands of cottonseed. III. Distribution of the pigments in the seed kernel. Bot. Gaz., 109:108-120. Boatner, C. H., C. M. Hall, R. T. O'Connor, L. E. Castillon and M. C. Curet, 1947. Processing of cottonseed. I. Pigment distribution in oils and meals produced by hydraulic and screw press methods. Am. Oil. J. Chem. Soc. 24:97-106. Boatner, C. H., C.*M. Hall, M. L. Rollins, and L. E. Castillon, 1947. The pigment glands of cottonseed. II. Nature and properties of the gland wall. Bot. Gaz. 108:484-494. Boatner, C. H., R. T. O'Connor, M..C. Curet, and C. S. Samuels, 1947. The pigments of cottonseed.
328
NEWS AND NOTES
III. Gossyfulvin, a native cottonseed pigment related to gossypol. J. Am. Chem. Soc. 69: 12681271. Carruth, F. E., 1917. Methods for approximating the relative toxicity of cottonseed products. J, Biol. Chem. 32: 87-90. Clark, C. F., 1936. Feeding cottonseed products to beef cattle. Miss. Agr. Expt. Stat. Bull. 317. Clark, E. P., 1928a. Studies on gossypol. II. Concerning the nature of Carruth's gossypol. J. Biol. Chem. 76: 229-235. Clark, E. P., 1928b. The composition and toxic effects of gossypol. Oil and Fat Ind. 5:237-242. Gallup, W. D., 1927. Heat and moisture as factors in the destruction of gossypol in cottonseed products, Ind. Eng. Chem. 19:726-728. Gallup, W D , 1928. Relation of d-gossypol to the toxicity of some cottonseed products. Ind. Eng. Chem. 20:59-63. Lyman, Carl M., Bryant R. Holland, and Fred Hale, 1944. Processing cottonseed meal. A manufacturing method for eliminating toxic qualities. Ind. Eng. Chem. 36:188-190.
Olcott, H. S., 9141. Solvent extraction of cottonseed oil. Effect of cooking on yield. Ind. Eng. Chem. 33:611-615. Olcott, H. S., 1942. Solvent extraction of cottonseed oil. Cotton and Cotton Oil Press 43(7): 24-25. Olcott, H. S. and T. D. Fontaine, 1941. The effect of autoclaving on the nutritive value of the protein in cottonseed meal. J. Nutrition 22:431-437. Sewell, W. E., 1943. The detoxification of cottonseed meal for hogs. Agri. Expt. Stat. Ala. Polytech. Inst. Bui. 259. Sewell, W. E. and D. M. Turney, 1946. Further experiments with detoxification of cottonseed meal for hogs. Agr. Espt. Stat. Ala. Polytech. Inst. Progress Report, Series No. 25, July. Vix, H. L. E., J. J. Spadaro, R. D. Westbrook, A. J. Crovetto, E. F. Pollard, and E. A. Gastrock, 1947. Prepilot plant mixed solvent flotation process for separating pigment glands from cottonseed meats. J. Am. Oil Chem. Soc. 24: 228-236. Withers, W. A. and F. E. Carruth, 1915. Gossypol, the toxic substance of cottonseed meal. J. Agri. Res. 5:261-288.
News and Notes (Continued from page 307)
Melvin V. Flock, Extension Poultryman, Purdue University, resigned effective March 15, 1948 to accept a position with the DeKalb Hybrid Seed Company. He will be in residence at DeKalb, Illinois and will work under the direction of Dr. E. E. Schnetzler. Ground was broken at the Purdue University poultry plant late in March for the erection of a 50 pen breeding house, 30X 201 feet, and a 6000 chick brooder house, 30X121 feet. One-half of the brooder house will have radiant floor heating and the other half for electric hovers and colony brooder stoves. These two buildings are being erected on the poultry plant immediately west of the present Poultry Building. The progeny test house, under construction at the 130 acre poultry
farm two and one-half miles southwest of the poultry building, are nearing completion. It is planned to let further contracts during the summer for service buildings, roads, fences, etc. As a tribute to Professor James E. Rice on the occasion of his 83rd birthday, Earl W. Benjamin has written a small booklet entitled "He Reaches the Souls of Men." A limited number of copies are available to interested friends and former students through S. L. Althouse, Watt Publishing Company, Mount Morris, Illinois. Under terms of the Fulbright Act (Public Law No. 584) foreign currency resulting from sale of surplus property abroad is available for purposes of educational exchange and activities in foreign
(Continued, on page 346)
H . C . SCHAEFER The Ralston Purina Company, St. Louis, Missouri (Received for publication October 29, 1947)
O I N C E cottonseed meal was one of the ^ first protein concentrates to be fed to to livestock on a large scale, numerous investigations were published relative to its nutritive value before the importance of balanced diets, and of vitamins, and other essential nutritional factors was recognized. Proper evaluation of cottonseed as a protein feed is rendered difficult by the mass of confusing and contradictory data which accumulated during the period of these early nutritional investigations. Numerous recent investigations have established the high nutritive value of hydraulic- and screw-pressed cottonseed meals produced by expression of the oil from cooked cottonseed. These cottonseed meals represent one of the most important sources of concentrated protein presently available to livestock feeders. The nutritive value of uncooked cottonseed has been established for beef cattle (Clark, 1 Present address, Division of Biologically Active Compounds, BAIC, Agricultural Research Center, Beltsville, Maryland. 2 One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration. U. S. Department of Agriculture.
1936), but for other livestock it is generally believed (Olcott, 1941, 1942) that cooking is essential in order to obtain cottonseed meal which is a satisfactory and safe livestock feed. Until recently, this has been a somewhat academic problem since cottonseed has always been processed in this country by expression of the oil from cooked seed. However, the question of the suitability of uncooked cottonseed as a livestock feed is now of practical importance, as well as some concern, because of the recent application of solvent extraction methods for processing cottonseed. Cooking of cottonseed has been reported (Olcott, 1941) to improve neither the yield nor the quality of the solvent-extracted oil. . The deleterious physiological effects of uncooked or partially cooked cottonseed have generally been attributed to the presence of gossypol, a yellow polyphenolic pigment which occurs in the cottonseed in concentrations as high as three percent of the weight of the kernel. Withers and Carruth (1915) were the first to observe the correlation between the decrease in the amount of gossypol which could be extracted with diethyl ether, and
315
316
BOATNER, ALTSCHUL, IRVING, POLLARD AND SCHAEFER
the improved nutritive value of the cooked seed. They also found that extraction of uncooked cottonseed with diethyl ether rendered the meal non-toxic when fed to rats and guinea pigs, whereas the diethyl ether extract was toxic to these animals. These and related observations led to the bound gossypol theory (Withers and Carruth, 1915, Carruth, 1917, Clark, 1928 and 1928b) of gossypol detoxification. According to this theory, gossypol was assumed to be solely responsible for the toxicity of raw cottonseed, and it was assumed, further, that the gossypol became inactivated during cooking of cottonseed as a result of its reaction with the protein in the seed to form so-called bound gossypol. The observation of Olcott (1941) that meal produced by extraction of uncooked cottonseed with petroleum naphtha was toxic to rats appears to lend additional support to this theory since extraction with petroleum naptha removes only a small fraction of the total gossypol present in the cottonseed kernel. On the other hand, the nutritional investigations of Gallup (1927, 1928), Lyman, Holland and Hale (1944), Sewell (1943) and Sewell and Turney (1946) have shown very poor correlation between the content oifree gossypol in meals obtained from cooked cottonseed, and their nutritive value for different experimental animals. Gallup (1928) concluded from his observations that other components of cooked cottonseed in addition to free and bound gossypol affect its nutritional value. It was recently shown (Boatner and Hall, 1946; Boatner, Hall, Rollins, and Castillon, 1947) that the pigment glands of cottonseed, which are distinct morphological structures peculiar to the cottonseed kernel and to the seed of a very few closely related genera, and which contain
most of the pigments of the kernel, are resistant to the action of hydrocarbon solvents, but are slowly ruptured during contact with diethyl ether. The pigment glands separated from seed of different varieties of Gossypium hirsutum, the species of cottonseed grown in largest quantity in the United States, have been found (Boatner, Hall, O'Connor, and Castillon, 1947) to be fairly uniform with respect to their content of pigments. Gossypol constitutes from 39 to 49 percent, and gossypurpurin (Boatner, 1944) from one to three percent of the weight of the glands. These were the only pigments which could be detected in the samples of isolated pigment glands which have been examined to date. Ethereal extracts of pigment glands represent approximately one half of the total weight of the glands, and gossypol and gossypurpurin constitute 80 to 90 percent of the weight of the material extracted from the glands by diethyl ether. In view of the somewhat contradictory reports concerning the toxicity of gossypol in cottonseed, it seemed possible that the high nutritive value of the meal produced by extraction of uncooked cottonseed with diethyl ether might be the result of the removal of components of the pigment glands other than gossypol, and that conversely, the toxicity of the meal produced by petroleum naptha extraction of uncooked cottonseed might result from the failure of the latter solvent to remove these toxic components of the pigment glands. The semi-pilot plant development (Vix, Spadaro, Westbrook, Crovetto, Pollard, and Gastrock, 1947), of the flotation process (Boatner and Hall, 1946) for the separation of intact pigment glands from the oil and protein tissue of the cottonseed kernel has made available pigment glands and gland-free cottonseed
T H E NUTRITIVE VALUE OF COTTONSEED FOR CHICKS
flour in quantities sufiicient for determining their physiological properties. Withers and Carruth (1915) noted that hydraulic-pressed cottonseed meal obtained from pre-cooked seed was inferior to the meal produced by extraction of uncooked cottonseed with diethyl ether when these meals were used in unsupplemented diets. Olcott and Fontaine (1941) also found that the protein nutritional value of meal obtained by extraction of uncooked cottonseed with diethyl ether decreased in proportion to the length of time of subsequent cooking of the extracted meal. It seemed probable therefore that gland-free cottonseed flours produced from uncooked cottonseed and subjected to only mild heating during processing should be superior in nutritive value to hydraulic-pressed cottonseed meal. There follows the report of an investigation of the effect on chick growth of various cottonseed products compared with that obtained on a basal diet containing 13 persent of screw-pressed soybean meal as the source of vegetable protein. The following cottonseed products were used in the experimental feeding tests; (1) hydraulic-pressed cottonseed meal, (2) hydraulic-pressed cottonseed meal extracted with commercial hexane, (3) uncooked cottonseed extracted with commercial hexane, (4) uncooked cottonseed extracted with diethyl ether, (5) the preceding solvent-extracted meals subsequently subjected to heat, (6) gland-free cottonseed flour, (7) soybean meal plus gossypol, and (8) soybean meal plus cottonseed pigment glands. In the case of the cottonseed meals, the experimental diets were prepared by substituting equal quantities of the cottonseed products in place of the soybean meal in the standard basal diets. Gossypol and separated pig-
317
ment glands were mixed in measured amounts with the standard soybean diet. These diets were fed under comparable conditions to lots of twenty to thirty chicks each for a period of six weeks. EXPERIMENTAL PROCEDURE
The. different series of experiments reported here were carried out over a period of three years and the soybean and cottonseed products were therefore produced from seed grown during three seasons. Preparation of cottonseed products The cottonseed products included in the diets for any one group of parallel feeding experiments were prepared from a single lot of prime seed, except the commercial hydraulic-pressed cottonseed meal which was used for comparative purposes in the diet of one lot of chicks. Hydraulic-pressed meals.—An ExportType Model of French hydraulic box press was used in preparing the cottonseed meals. One pound of water was added to
each forty-pound charge of flaked meats before cooking. The meats were cooked for forty minutes (20 minutes in each of the two stacks of the cooker) to a final temperature of 120°C. (248°F.). Oil was expressed from the cooked meats under a pressure of 4,000 Ib/sq. in. on the ram (1,760 Ib./sq. in. on the plates) for fifteen minutes. The sample of commercial hydraulicpressed cottonseed meal represented a random selection of standard prime quality cake which was produced by a commercial processor in Mississippi. Solvent-extracted cottonseed.—The meats used for preparing the solvent-extracted cottonseed meal and gland-free cottonseed flour were cracked and flaked on rolls set with clearances of 0.025 and 0.0015 in.,
respectively.
318
BOATNER, ALTSCHUL, IRVING, POLLARD AND SCHAEFER
Hexane-extracted cottonseed was prepared by extracting flaked seed in a single cell, batch extractor with commercial hexane.3 The extraction was carried out for six hours, and the solvent in contact with the flakes was maintained at a maximum temperature of 30°C. (85°F.). The solvent-extracted meal was freed of solvent by air-drying. Solvent-extracted press cake was prepared by extracting ground hydraulicpressed cake with commercial bexane in the same extractor and under the same conditions as described above. Diethyl ether-extracted cottonseed meal used for the first feeding experiment was prepared in the same equipment and under the same conditions employed with hexane. Commercial grade diethyl ether was used. The diethyl ether-extracted cottonseed meal used in the last feeding experiment was prepared in a battery of Soxhlet extractors. Commercial grade diethyl ether was refluxed through the flaked meats for three hours. The ether was then allowed to remain in contact with the seed in the extractor overnight at room temperature. Refluxing of the ether was then continued for another three hours after which the meal was freed of residual solvent by airdrying. Gland-free cottonseed flour.—This product was prepared by the semi-pilot plant development (Vix, Spadaro, Westbrook, Crovetto, Pollard, and Gastrock, 1947) of the flotation process (Boatner and Hall, 1946) using a mixture of commercial hexane and tetrachlorethylene of density 1.378 g./cc. The moisture content of the flaked seed was reduced to approximately five percent by heating at 51.5°C. (125°F.) 3 The commercial hexane used throughout this investigation had a boiling range of 63°-70°C. (146°158°F.).
for two hours in a drying oven before separating the oil and glands by flotation. The dried flakes were disintegrated in the solvent mixture, most of the pigment glands separated by flotation, and the residual meal was re-processed to remove any remaining pigment glands. The glandfree cottonseed flour was washed on a filter cloth four times with commercial hexane. The flour was then de-solventized in a vacuum tray dryer. One sample of gland-free flour was dried at a maximum temperature of 47°C. (117°F.) and the other at a maximum temperature of 99°C. (210°F.). Cottonseed pigment glands.—The glands were obtained from flaked cottonseed by the flotation process carried out as described above. The concentrated preparation of glands obtained in the first flotation step consisted of a slurry of pigment glands, fine meal, and solvent. Portions of approximately 300 g. of this slurry were suspended with 300 g. of silica (300 mesh) in a solvent mixture having a density of 1.378 g./cc. and the suspension agitated vigorously for forty-five minutes. The layer of pigment glands which rose to the surface of the solvent mixture on standing was removed, washed several times with commercial hexane, screened on a 230mesh sieve in order to remove fine particles of meal, and dried in a vacuum desiccator at room temperature. Gossypol.—Gossypol was prepared from an ethereal extract of cottonseed according to the procedure described by Boatner, O'Connor, Samuels, and Curet (1947). Crude gossypol was separated from the ethereal -extract by extraction with aqueous alkali, and the alkaline extract acidified and re-extracted with diethyl ether. Gossypol-acetic acid was precipitated from the last mentioned extract, after which it was hydrolyzed by suspending it in boiling water for one hour.
T H E NUTRITIVE VALUE OF COTTONSEED FOR CHICKS
Impurities were removed by digesting the crude gossypol with toluene at room temperature. The purity of the gossypol was established by application of the antimony trichloride-spectrophotometric test for gossypol (Boatner, Caravella, and lOyame, 1944). Determination of the pigment contents of the cottonseed products.—Chloroform extracts of meal and gland fractions were prepared by equilibration of weighed samples with measured volumes of chloroform for twenty-four hours at 3.3°C. (38°F.) in the absence of light (Boatner, Hall, O'Connor and Castillon, 1947). Aqueous ethanol extracts were prepared by adding 30 ml. of aqueous ethanol (30 percent ethanol by weight) to weighed samples of glands or meal. The suspension was allowed to stand at room temperature with occasional shaking for ten to thirty minute.s, after which 70 ml. of aqueous ethanol (72 percent ethanol by weight) was added to the suspension. The suspension was thoroughly agitated and then centrifuged, and aliquots of the supernatant were removed for transfer of the dissolved material to chloroform (Boatner, Hall, O'Connor, and Castillon, 1947). The concentration of gossypol in the chloroform extracts and in chloroform solutions of the ethanol extracts was determined by application of the antimony trichloride-spectrophotometric method for gossypol (Boatner, Caravella, and Kyame, 1944). The concentration of gossyfulvin (Boatner, Caravella, Samuels 1944; Boatner, O'Connor, Samuels, and Curet, 1947) in the extracts was estimated on the basis of the increase in the extinction coefficient at 520m/i of the antimony trichloride reaction product obtained by treating the extract with concentrated hydrochloric acid, before adding antimony trichloride. The concentration of gossypurpurin
319
(Boatner 1944; Boatner, Hall, O'Connor, Castillon, and Curet, 1947) in the samples of meal and glands was determined on the basis of the specific extinction coefficients of the chloroform extracts at 565 to 566m/i. The percentage of gossypurpurin in each sample was calculated by means of the equation ( E ^ m . extract/Eif m . gossypurpurin X100) where E i ^ . extract is the specific extinction coefficient of the chloroform extract at 565 to 566mju, and El^°m. gossypurpurin is the specific extinction coefficient of pure gossypurpurin at the same wavelength (Boatner, Hall, O'Connor, Castillon, and Curet, 1947). Preparation of screw-pressed soybean meal The soybean meal used for the feeding experiments consisted of a standard, commercial grade, screw-pressed meal prepared by the following procedure. Soybeans were cracked to give a product in which 55 percent was held on an 8-mesh screen and 30.5 percent on a 10-mesh screen. The cracked beans were dried to a moisture content of 1.4 percent and heated to a temperature of 137°C- (278°F.) before entering the presses. The oil was pressed from the beans under a pressure of 12,000 lb./sq. in. within the press. The beans remained in the press for about two minutes, and the meal reached a final temperature of approximately 149°C. (300°F.). Preparation of diets All of the ingredients used in the basal ration common to all of the diets were combined in a mixture which constituted 87 percent of the total diet. The ingredients were selected from a common source and represented standard ingredients used for poultry starting feeds. A mixture of wheat bran, wheat middling,
320
BOATNER, ALTSCHUL, IRVING, POLLARD AND SCHAEFER
ground oats, meat scrap, fish meal, dehydrated alfalfa, calcium carbonate, corn gluten meal, riboflavin, sodium chloride, and vitamin D 3 constituted 42.3 percent, and yellow corn 57.7 percent of the basal ration. Eighty-seven parts of this basal mixture were mixed thoroughly with 13 parts of soybean or cottonseed meal. The average protein content of the final experimental diets was 22 percent. Therefore, 13 percent of soybean or cottonseed meal containing 43 percent protein contributed approximately 25 percent of the total protein of the diet. Portions of gossypol or pigment glands to be added to the soybean basal diet were accurately weighed on an analytical balance. They were pre-mixed with part of the basal diet, and this mixture was then thoroughly incorporated into the whole of the experimental ration. Feeding experiments The chicks used in the feeding experiments were hatched at the Purina Research Farm. The laying hens received rations known to assure normal offspring. The chicks were housed at the Biological Laboratory of the Ralston Purina Company in commercial type battery brooders, heated electrically, and equipped with wire floors. The room in which the chicks were housed was maintained at a temperature of 24° to 27°C. (75° to 80°F.) and a relative humidity of 45 to 55 percent. The batteries were all arranged vertically so that some lots of chicks were at higher levels than others. In previous work it had been observed that it made little or no difference as far as growth is concerned, whether the chicks were on the lower or upper tiers. The feed for the chicks was weighed, and the chicks had access to feed at all times. The feed hoppers and water containers
were attached to the side of the brooder in such a way that the birds could eat or drink at will. The chicks were weighed as a group at the beginning of the experiment, and individually at the end of the test. The weights were recorded in grams, using a balance calibrated to weigh accurately to one-half gram. The amount of feed consumed was obtained by the difference in weight of the feed placed in the hoppers and the unconsumed portions. Comparison 'of hydraulic-pressed cottonseed and screw-pressed soybean meals.—• Hydraulic-pressed cottonseed produced in the pilot plant was substituted for screwpressed soybean meal in two basal diets, and the soybean and cottonseed meal diets were fed ad libitum for six weeks to four parallel lots of twenty each White Plymouth Rock chicks. The average gains in weight of the two lots of chicks fed cottonseed meal were 433 g. and 324 g., respectively, which was significantly less than the average gains of 486 g. and 435 g., respectively, made by the two lots which were fed the standard soybean meal diets. Comparison of uncooked, hexane-extracted cottonseed and screw-pressed soybean meal.—When cottonseed meal produced in the pilot plant by extraction of flaked meats with commercial hexane was substituted for screw-pressed soybean meal in the same two basal diets as were used in the preceding series, the average gains of the chicks were very much less than those of the chicks in the preceding series which were fed diets containing hydraulic-pressed cottonseed meal. The average gains of two lots of twenty chicks each on diets containing uncooked, hexane-extracted cottonseed were 277 g. and 256 g., respectively, whereas the average gains made by two control lots on standard diets containing soybean meal were 401 g. and 395 g., respectively.
321
T H E NUTRITIVE VALUE OF COTTONSEED FOR CHICKS
Comparison of hydraulic-pressed cottonseed meal; hydraulic-pressed cottonseed meal extracted with hexane; uncooked hexane-extracted cottonseed; soybean meal; and soybean meal plus gossypol.—In order to eliminate variations which might result from differences in composition of the seed, this series, and each succeeding series of feeding experiments, was carried
of the average gain in weight of the control lot on the standard soybean diet. From these data it can be seen that both samples of hydraulic-pressed cottonseed meal supported gains approximately equal to those of the control lot. Although the slightly lower gains made with hydraulicpressed cottonseed meal which had been extracted with hexane are not readily
TABLE 1.—Effect of gossypol and various hydratdic-pressed cottonseed meals on chick growth Composition of diets 1 Protein, % Riboflavin, p.p.m. Gossypol, %
Ration 1 21.85 5.7 None
Ration 2 20.71 4.6
Results of feeding tests 6 Av. starting weight, g. Av. wt. at 6 weeks, g. Av. gain, g. Livability, % Av. gain, % of control
36.0 459.9 423.9 100 100
35.8 458.9 423.1 100 100
2
Ration 3 21.31 5.6 none 3
Ration 4 21.54 5.4 0.13
Ration 5 21.66 5.5
35.9 449.1 413.2 100 97.5
35.7 385.1 349.4 100 82.5
36.0 418.3 382.3 100 90.0
2
Ration 6 21.45 5.7 0.13 4 35.8 163.7 127.9 100 30.0
1 The diets contained 13 percent of the following: screw-pressed soybean meal in Ration 1 (control); hydraulic-pressed cottonseed meal (commercial) in Ration 2; hydraulic-pressed cottonseed meal (pilot plant) in Ration 3; screw-pressed cottonseed meal plus gossypol (0.13 percent) in Ration 4; hydraulicpressed cottonseed meal (pilot plant), extracted with hexane in Ration 5; and uncooked, hexane-extracted cottonseed in Ration 6. Other components of these diets: moisture, 9.29 percent; fat, 3.78 percent; fiber, 5.27 percent; N.F.E., 54.51 percent; ash, 5.33 percent; calcium, 1.26 percent; phosphorus, 0.76 percent; manganese, 59 p.p.m.; carotene, 10.10 p.p.m.; xanthophyll, 15.80 p.p.m.; thiamin, 2.90 p.p.m.; pantothenic acid, 17.00 p.p.m.; niacin, 3.50 p.p.m. 2 Not determined. 3 No gossypol, 0.04 percent gossyfulvin. 4 The gossypol content of the extracted meal was estimated on the basis of that of the original meats, assuming no gossypol was extracted by commercial hexane. 8 The rations were fed for six weeks to lots of 30 white leghorn chicks, one day old at beginning of experiment.
out with products prepared from the same lot of cottonseed. Since essentially similar results had been obtained with the two basal diets, only one basal diet was used in this experiment and subsequent experiments. The composition of the diets and gains in weight and other pertinent data for the chicks used in this series of feeding experiments are given in Table 1. In order to facilitate comparison of results obtained with the different diets, the average gain in weight of each lot of chicks was calculated as the percentage
explainable, they eliminate the possibility that the very poor gains made with uncooked, hexane-extracted cottonseed resulted from the presence of residual solvent or alteration of the components of the uncooked seed by the solvent. Finally, although addition of gossypol to the standard soybean diet caused definite retardation in growth, the deleterious effect of the uncooked, hexane-extracted cottonseed Was very much greater than that caused by gossypol alone. The deleterious effect of the uncooked seed appears, therefore, to be attributable to
322
BOATNER, ALTSCHUL, IRVING, POLLARD AND SCHAEFER
some component of the seed in addition to gossypol, and the superior nutritional value of hydraulic-pressed cottonseed meal appears to be the result of partial or complete destruction during cooking of the physiologically active components of the raw seed or to their removal during subsequent expression of the oil. The superficial physical condition of typical chicks to which the above-described diets were fed may be seen in Figure 1. It is apparent that the physical condition of the chicks which received gossypol in the basal (soybean) diet is inferior to that of the chicks on the control diet (soybean) but it is very much better than that of the chicks fed TABLE 2.—Effect
Composition of diets 1 Moisture, % Protein, % Fat, % Crude fiber, % Ash, % N.F.E., % Calcium, % Phosphorus, % Manganese, p.p.m. Carotene, p.p.m. Xanthophyll, p.p.m. Thiamin, p.p.m. Niacin, p.p.m. Riboflavin,p.p.m. Gossypol, % Gossypurpurin, %
Ration 1 8.07 24.71 5.17 6.70 6.71 48.64 1.48 0.80 90.2 8.0 15.8 3.89 37.5 5.85 none none
Results of feeding tests1! Av. starting weight, g. 37.5 Av. weight at 6 wks., g. 501.2 Av.gain.g. 463.7 Av. feed consumption, g. 1057.7 Av. g. feed per g. gain 2.28 Livability, % 96 Av. gain, % of control 100
diets containing uncooked hexane-extracted cottonseed. Comparison of uncooked, diethyl etherextracted cottonseed; uncooked, hexaneextracted cottonseed; solvent-extracted meals after cooking; hydraulic-pressed cottonseed; and soybean meal.—The composition of the diets, gains in weight of the different lots of chicks, and other pertinent data for this series of feeding tests are shown in Table 2. Better growth was obtained with the diet containing hydraulic-pressed cottonseed meal than was obtained with the soybean meal. Extraction of the hydraulic-pressed cottonseed meal with commercial hexane reduced its nutritional
of various hydraulic-pressed and solvent-extracted cottonseed meals on chick growth
Ration 2 8.67 25.04 5.68 6.72 6.68 46.52 1.49 0.87 87.2 8.5 16.0 5.40 42.3 5.25 0.07 0.0081
Ration Ration 3 4 8.82 7.88 26.00 25.90 5.70 4.93 6.56 6.57 6.90 6.82 46.96 46.96 1.46 1.44 0.95 0.93 84.0 90.8 7.8 8.1 15.7 16.7 6.26 5.84 39.4 44.6 5.39 5.32 0.03 0.46 0.0076 < 0.033
Ration Ration 5 6 9.08 8.66 25.76 26.02 4.92 5.67 6.57 6.48 6.86 6.64 45.98 46.81 1.47 1.59 0.92 0.91 98.0 90.1 8.4 8.2 15.6 17.0 5.94 5.70 40.7 41.3 5.14 4.81 0.30 0.01 0.036 0.0020
Ration Ration 7 8 8.58 8.49 26.44 26.21 4.74 5.67 7.21 6.58 6.90 7.09 46.13 45.96 1.57 1.55 0.91 0.90 81.1 85.0 7.4 7.2 15.0 15.1 5.83 5.87 41.3 39.9 4.76 4.46 0.01 0.01 0.0015 0.00045
37.6 523.9 486.3
37.7 500.8 463.1
37.7 288.0 240.3
37.8 324.3 286.5
37.5 436.3 398.8
37.3 455.8 418.5
37.7 457.2 419.5
1037.4 2.13 100 105
980.9 2.12 100 100
819.2 3.41 100 52
895.7 3.13 100 62
897.7 2.25 100 86
1020.8 2.44 100 90
950.5 2.27 100 91
1 The diets contained 13 percent of the following: screw-pressed soybean meal in Ration 1 (control); hydraulic-pressed cottonseed meal in Ration 2; hydraulic-pressed cottonseed meal extracted with hexane in Ration 3; uncooked, hexane-extracted cottonseed in Ration 4; hexane-extracted cottonseed, wet-cooked 15 minutes in Ration 5; uncooked, diethyl ether-extracted cottonseed in Ration 6; diethyl ether-extracted cottonseed dry-cooked 16 hours in Ration 7; and diethyl ether-extracted cottonseed, wet-cooked 15 minutes in Ration 8. 2 The rations were fed for six weeks to lots of 25 White Plymouth Rock chicks, one day old at beginning of experiment.
T H E NUTRITIVE VALUE OF COTTONSEED EOR CHICKS
323
: •
• 0^|»f
o
<•*••
araa
FIG. 1. Appearance of typical 6-week old chicks from parallel lots fed rations containing: (a) soybean meal (control), (b) commercially hydraulic-pressed cottonseed meal, (c) soybean meal plus gossypol, (d) hydraulicpressed cottonseed meal (Pilot plant), (e) hydraulic-pressed cottonseed meal extracted with hexane, (f) uncooked cottonseed extracted with commercial hexane.
324
BOATNER, ALTSCHUL, IRVING, POLLARD AND SCHAEFER
value to that of the soybean meal. The average gain in weight of chicks fed uncooked, hexane-extracted cottonseed was very poor, and heating of the extracted meal for 15 minutes in the presence of moisture resulted in only slight improvement in its nutritional value. The meal obtained by extraction of uncooked cottonseeed with diethyl ether produced better growth than the hexane-extracted cottonseed, but Jess gain than was obtained with the hydraulic-pressed cottonseed meal. Cooking of the diethyl etherextracted seed in the presence of moisture for fifteen minutes at 116°C. increased its nutritional value to about the same extent as heating it in the absence of moisture for sixteen hours at -70° to 80°C.
cottonseed and both of the gland-free cottonseed flours supported somewhat better growth than the screw-pressed soybean meal. All three of these cottonseed products contained relatively insignificant amounts of gossypol and no gossypurpurin. The diethyl ether-extracted cottonseed contained more gossypol, but supported slightly better growth, than did either of the gland-free cottonseed flours. The growth of chicks fed hexaneextracted cottonseed was somewhat superior to that of the chicks fed the standard diet to which cottonseed pigment glands had been added. The diet of the former lot of chicks contained slightly more gossypol and less gossypurpurin than the diet which contained added cottonseed pigment glands.
A poor correlation was found between the nutritional value of the different cottonseed meals and their content of extractable gossypol and gossypurpurin. Although the hydraulic-pressed cottonseed meal produced better gains than did the meal obtained by extraction of uncooked cottonseed with diethyl ether, the extracted seed contained less extractable gossypol and gossypurpurin than did the hydraulic-pressed meal. The increase in the nutritional value resulting from cooking the extracted seed was greater than might have been predicted on the basis of the slight decrease which occurred in the extractable pigments as the result of cooking. Comparison of gland-free cottonseed flour; uncooked diethyl ether-extracted cottonseed; uncooked hexane-extracted cottonseed; soybean meal; and soybean meal plus pigment glands.—The composition of the diets, gains in weight of the chicks during six weeks' feeding of the different diets, and other pertinent data for this series of feeding tests are shown in Table 3. The uncooked, diethyl ether-extracted
Histological examination4 of liver and kidney sections showed no detectable differences between those from the control lot of chicks and those from the lot fed pigment glands, except for a slightly more intense nuclear staining of the cells of the liver in the case of the chicks fed pigment glands. This condition did not appear to represent an inflammatory change and was of no apparent pathological significance, but indicated only some special affinity of these particular nuclear remains for hematoxylin stain. The weekly growth curves of chicks on the different diets are shown in Figure 2. Since the growth curve of chicks on gland-free cottonseed flour de-solventized at a maximum temperature of 47° C. (Ration 3) was almost exactly the same as that of chicks on the other gland-free cottonseed flour (Ration 4), it is not shown. Comparison of the growth curves show's that the diethyl ether-extracted 1 Performed by the Gradwohl Laboratories, St. Louis, Missouri.
T H E NUTRITIVE VALUE OF COTTONSEED FOR CHICKS
TABLE 3.—Effect
325
of various solvent-extracted cottonseed meals, gland-free cottonseed flours, and cottonseed pigment glands on chick growth Ration 5 8.67 20.52 4.00 5.92 7.07 53.82 1.66 0.66 84.00 12.40 18.50 6.00 0.244 0.0075
Ration 6 9.21 20.52 3.95 5.59 7.01 53.67 1.65 0.66 90.00 12.00 18.20 6.50 none none
Composition of diets 1 Moisture, % Protein, % Fat, % Crude fiber, % Ash, % N.F.E., % Calcium, % Phosphorus, % Manganese, p.p.m. Carotene, p.p.m. Xanthophyll, p.p.m. Riboflavin, p.p.m. Gossypol, % Gossypurpurin, %
Ration 1 9.02 21.82 3.46 5.55 7.19 52.96 1.63 0.75 74.00 12.20 16.50 6.00 0.250 0.0052
Ration 2 9.87 21.15 3.17 5.47 7.28 53.06 1.68 0.75 80.00 12.20 16.00 6.80 0.0032 none
Ration 3 9.46 21.73 3.10 3.76 7.21 54.74 1.70 0.76 73.00 11.70 15.80 6.00 0.00078 none
Results of feeding tests 2 Av. st. weight—g. Av. wt.—1st wk., g. Av. wt.—2nd wk., g. Av. wt.—3rd wk., g. Av. wt.—4th wk., g. Av. wt.—5th wk., g. Av. wt.—6th wk., g. Av. gain, g.
35.7 58.0 72.9 89.7 114.4 144.2 170.9 135.2
35.7 •75.5 131.0 207.3 296.5 390.5 508.5 472.8
35.7 70.8 124.5 200.0 282.6 379.9 485.1 449.4
35.7 72.3 123.0 197.3 287.8 392.7 488.1 452.4
35.7 62.3 78.8 91.7 103.2 122.0 143.8 108.1
35.7 70.5 117.3 190.5 265.5 356.4 454.0 418.3
61.5 107.0 172.0 206.8 291.0 311.0 1149.3 2.43 100 good 113
72.0 117.8 179.5 232.9 310.0 356.8 1269.0 2.82 95 good 108
65.8 107.0 162.5 211.3 299.0 316.0 1161.6 2.57 100 good 108
72.0 78.5 108.4 149.4 217.5 164.8 790.6 7.31 75 poor 26
68.8 101.0 162.0 207.5 276.0 299.0 1114.3 2.66 100 good 100
Av. feed cons.—1st wk., g. 56.5 Av. feed cons.—2nd wk., g. 69.5 Av. feed cons.—3rd wk., g. 105.2 Av. feed cons.—4th wk., g. 152.2 Av. feed cons.—5th wk., g. 246.5 Av. feed cons.—6th wk., g. 322.9 Av. total feed cons., g. 952.9 Av. g. feed per g. gain 7.05 Livability, % 85 Condition of chicks poor Av. gain, % of control 32
Ration 4 8.44 22.12 3.55 3.16 7.26 55.47 1.68 0.78 84.00 14.70 16.00 6.00 0.00078 none
1 The rations contained 13 percent of the following: uncooked, hexane-extracted cottonseed in Ration 1; uncooked, diethyl ether-extracted cottonseed in Ration 2; gland-free cottonseed flour, desolventized at maximum temperature of 47°C. in ration 3; gland-free cottonseed flour desolventized at maximum temperature of 99°C. in Ration 4; screw-pressed soybean meal plus cottonseed pigment glands (0.65 percent) in Ration 5; and screw-pressed soybean meal in Ration 6 (control). 2 The rations were fed for six weeks to lots of 20 White Plymouth Rock chicks, one day old at beginning of experiment.
cottonseed and the gland-free cottonseed flour initially produced slightly better gains than did the soybean meal, and that they produced increasingly improved gains throughout the six-week period. The hexane-extracted cottonseed and soybean meal plus cottonseed pigment glands caused retardation in growth from the beginning of the experiment, and their deleterious effect became more pronounced as the feeding was continued.
DISCUSSION
It may be concluded from these experiments that all of the components of the cottonseed kernel which are injurious to chicks are segregrated- in the pigment glands, and that uncooked cottonseed can be freed of these objectionable components by exhaustive extraction with diethyl.ether or by mechanical removal of the pigment glands. Furthermore, since cottonseed pigment glands added to
326
BOATNER, ALTSCHXJL, IRVING, POLLARD AND SCHAEFER
J I
I 2
I »
I »
I »
A O E - WEEKS
FIG. 2. Growth curves of chicks on diets containing (1) uncooked, hexane-extracted cottonseed, (2) uncooked, diethyl ether-extracted cottonseed, (3) gland-free cottonseed flour, desolventized at maximum temperature of 47°C. (same as 4), (4) glandfree cottonseed flour, desolventized at maximum temperature of 99°C, (5) screw-pressed soybean meal, plus cottonseed pigment glands, (6) screwpressed soybean meal (control).
a diet containing no other cottonseed product produced approximately the same retardation in the growth of chicks as uncooked hexane-extracted cottonseed, it can be concluded that the deleterious effects of the pigment glands are not dependent upon their interaction with either the protein or the other extraglandular components of the cottonseed. Gossypol has been shown (Boatner, Hall, O'Connor, and Castillon, 1947) to be the principal component of cottonseed pigment glands, and gossypurpurin, a derivative of gossypol, is the only other extractable pigment which was found in detectable amounts in the cottonseed
•
pigment glands used in the feeding experiments and in other samples of cottonseed pigment glands which have been examined (Btoatner, Hall, O'Connor, and Castillon, 1947). The poor correlation which was observed between the nutritional values of the different cottonseed products and their relative contents of gossypol and gossypurpurin, coupled with the very slightly deleterious effect of gossypol added to the diet, indicates that components of the glands other than these pigments are responsible for the deleterious effect on chicks of cottonseed pigment glands. It has been shown (Boatner, Hall, O'Connor, and Castillon, 1947) that gossypol and its antimony trichloride reaction product suffer no alteration in their visible and ultraviolet absorption spectra during isolation and subsequent purification by the same methods as were employed in the preparation of the gossypol used in these experiments. In addition, the behavior of cottonseed pigment glands with water and various organic-solvents (Boatner, Hall, Rollins, and Castillon, 1947) indicates that the extractable gossypol and gossypurpurin of the glands occur as a gelatinous suspension rather than in chemical combination with other components of the glands. The superiority of the hydiaulie-pressed cottonseed meal to uncooked, hexaneextracted cottonseed can be attributed to inactivation of the toxic factors of the pigment glands during cooking of the seed, or to their removal during expression of the oil, or to both. Since all of the hydraulic-pressed cottonseed meals prepared in the pilot plant were processed under practically identical conditions, the slight variations in their nutritional values appear to be attributable to differences in the composition of the
T H E NUTRITIVE VALUE OF COTTONSEED FOR CHICKS
different lots of cottonseed. It is noteworthy that the hydraulic-pressed meals were precooked before pressing for only forty minutes. The improvement in the nutritional value which resulted from heating the meal from solvent-extracted seed apparently can be attributed to partial inactivation of the residual deleterious physiological factors of the pigment glands in the solvent-extracted seed. Heating the gland-free cottonseed flour during de-solventization had no appreciable effect on its nutritive value. SUMMARY An investigation is reported of the effect on the growth of chicks of uncooked cottonseed extracted with hexane, uncooked cottonseed extracted with diethyl ether, the foregoing solvent-extracted meals subsequently heated, hydraulicpressed cottonseed meal,hydraulic-press"d cottonseed meal extracted with hexane, gland-free cottonseed flour, gossypol, and cottonseed pigment glands. The cottonseed meals were substituted for soybean meal in a basal diet containing 13% of screw-pressed soybean meal as the source of vegetable protein, and the gossypol and pigment glands were added in measured amounts to the basal soybean meal diet. The basal soybean meal diet and the experimental cottonseed diets were fed to parallel lots of 20 to 30 chicks each for a period of six weeks. Gland-free cottonseed flour; uncooked, diethyl ether-extracted cottonseed; and hydraulic-pressed cottonseed meal supported excellent growth, whereas markedly inferior growth resulted when the experimental diets containing uncooked, hexane-extracted cottonseed or pigment glands were fed to chicks. These results showed that all of the physiologically deleterious components of cottonseed are segregated in the pigment glands.
327
Pure gossypol added to the diet produced relatively little retardation in the growth of chicks, and a poor correlation was found between the nutritional values of the various cottonseed products and their contents of gossypol and gossypurpurin. ACKNOWLEDGMENT The authors wish to acknowledge with appreciation the assistance in this investigation which was rendered by L. E. Castillon, M. C. Curet, M. E. Curet, T. D. Fontaine, E. A. Gastrock, C. M. Hall, M. L. Karon, E. L. D'Aquin, W. F. Guilbeau, E. J. McCourtney, C. H. Murphy, R. M. Persell, J. Pominski, C S. Samuels, J. J. Spadaro, and H. L. E. Vix of the Southern Regional Research Laboratory, W. T. Chilson of the Ralston Purina Company and H. Patrick formerly of the Ralston Purina Company. REFERENCES
Boatner, C. H., 1944. The pigments of cottonseed. Oil & Soap 21:10-15. Boatner, C. H., M. Caravella, and L. Kyame, 1944. Quantitative determination of extractable gossypol in cottonseed and cottonseed meal. Ind. Eng. Chem., Anal. Ed. 16: 566-572. Boatner, C. H., M. Caravella and C. S. Samuels, 1944. An orange-colored pigment of cottonseed. J. Am. Chem. Soc. 66:838. Boatner, C. H., and C. M. Hall, 1946. The pigment glands of cottonseed. I. Behavior of the glands toward organic solvents. Oil & Soap 22: 123-128. Boatner, C. H., C. M. Hall, R. T. O'Connor, and L. E. Castillon, 1947. The pigment glands of cottonseed. III. Distribution of the pigments in the seed kernel. Bot. Gaz., 109:108-120. Boatner, C. H., C. M. Hall, R. T. O'Connor, L. E. Castillon and M. C. Curet, 1947. Processing of cottonseed. I. Pigment distribution in oils and meals produced by hydraulic and screw press methods. Am. Oil. J. Chem. Soc. 24:97-106. Boatner, C. H., C.*M. Hall, M. L. Rollins, and L. E. Castillon, 1947. The pigment glands of cottonseed. II. Nature and properties of the gland wall. Bot. Gaz. 108:484-494. Boatner, C. H., R. T. O'Connor, M..C. Curet, and C. S. Samuels, 1947. The pigments of cottonseed.
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NEWS AND NOTES
III. Gossyfulvin, a native cottonseed pigment related to gossypol. J. Am. Chem. Soc. 69: 12681271. Carruth, F. E., 1917. Methods for approximating the relative toxicity of cottonseed products. J, Biol. Chem. 32: 87-90. Clark, C. F., 1936. Feeding cottonseed products to beef cattle. Miss. Agr. Expt. Stat. Bull. 317. Clark, E. P., 1928a. Studies on gossypol. II. Concerning the nature of Carruth's gossypol. J. Biol. Chem. 76: 229-235. Clark, E. P., 1928b. The composition and toxic effects of gossypol. Oil and Fat Ind. 5:237-242. Gallup, W. D., 1927. Heat and moisture as factors in the destruction of gossypol in cottonseed products, Ind. Eng. Chem. 19:726-728. Gallup, W D , 1928. Relation of d-gossypol to the toxicity of some cottonseed products. Ind. Eng. Chem. 20:59-63. Lyman, Carl M., Bryant R. Holland, and Fred Hale, 1944. Processing cottonseed meal. A manufacturing method for eliminating toxic qualities. Ind. Eng. Chem. 36:188-190.
Olcott, H. S., 9141. Solvent extraction of cottonseed oil. Effect of cooking on yield. Ind. Eng. Chem. 33:611-615. Olcott, H. S., 1942. Solvent extraction of cottonseed oil. Cotton and Cotton Oil Press 43(7): 24-25. Olcott, H. S. and T. D. Fontaine, 1941. The effect of autoclaving on the nutritive value of the protein in cottonseed meal. J. Nutrition 22:431-437. Sewell, W. E., 1943. The detoxification of cottonseed meal for hogs. Agri. Expt. Stat. Ala. Polytech. Inst. Bui. 259. Sewell, W. E. and D. M. Turney, 1946. Further experiments with detoxification of cottonseed meal for hogs. Agr. Espt. Stat. Ala. Polytech. Inst. Progress Report, Series No. 25, July. Vix, H. L. E., J. J. Spadaro, R. D. Westbrook, A. J. Crovetto, E. F. Pollard, and E. A. Gastrock, 1947. Prepilot plant mixed solvent flotation process for separating pigment glands from cottonseed meats. J. Am. Oil Chem. Soc. 24: 228-236. Withers, W. A. and F. E. Carruth, 1915. Gossypol, the toxic substance of cottonseed meal. J. Agri. Res. 5:261-288.
News and Notes (Continued from page 307)
Melvin V. Flock, Extension Poultryman, Purdue University, resigned effective March 15, 1948 to accept a position with the DeKalb Hybrid Seed Company. He will be in residence at DeKalb, Illinois and will work under the direction of Dr. E. E. Schnetzler. Ground was broken at the Purdue University poultry plant late in March for the erection of a 50 pen breeding house, 30X 201 feet, and a 6000 chick brooder house, 30X121 feet. One-half of the brooder house will have radiant floor heating and the other half for electric hovers and colony brooder stoves. These two buildings are being erected on the poultry plant immediately west of the present Poultry Building. The progeny test house, under construction at the 130 acre poultry
farm two and one-half miles southwest of the poultry building, are nearing completion. It is planned to let further contracts during the summer for service buildings, roads, fences, etc. As a tribute to Professor James E. Rice on the occasion of his 83rd birthday, Earl W. Benjamin has written a small booklet entitled "He Reaches the Souls of Men." A limited number of copies are available to interested friends and former students through S. L. Althouse, Watt Publishing Company, Mount Morris, Illinois. Under terms of the Fulbright Act (Public Law No. 584) foreign currency resulting from sale of surplus property abroad is available for purposes of educational exchange and activities in foreign
(Continued, on page 346)