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The Utilization of Unextracted Raw and Extruded Full-Fat Soybeans by the Chick
The Utilization of Unextracted Raw and Extruded Full-Fat Soybeans by the Chick A. S. WOOD, J. D. SUMMERS, E. T. MOEAN, JR. AND W. F. PEPPER
Department of Poultry Science, University of Guelph, Guelph, Ontario, Canada (Received for publication February 19, 1971)
T
EXPERIMENTAL PROCEDURE
Three experiments were carried out to compare the utilization of a standard cornsoy diet versus unextracted raw and extruded soybean supplemented diets. Extrusion process. Whole soybeans were hammer milled prior to the extrusion process (Wenger X-1S0 model extruder).1 In essence, the ground whole soybean meal was passed through a preconditioner where 30-40 lb. steam was introduced into the meal raising the temperature to 210°F. subsequent to being fed into the extruder. The extruder is a closed tapered barrel with a revolving screw and a narrow diehead opening at one end. The screw extrudes the material through the die-head opening where a combination of temperature of the material and friction result in an extrusion temperature of 2SS°F. As the cooked fullfat meal emerges from the extruder a fast reduction of pressure occurs which causes the material to expand rapidly and rupture most of the oil cells. Day-old White Leghorn male chicks were used in the experiments, were weighed at day of age and randomly assigned to pens on the basis of body weight. Five replicate groups of 10 chicks each were fed the experimental diets (Table 1) from 1 to 42 days of age. The chicks were reared in electrically heated battery brooders in which the experimental diets (in mash form) and tap water were supplied ad libitum. Body 1
Wenger Manufacturing, Kansas City, Mo. 64112, U.S.A.
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HE use of full-fat soybean in poultry diets is of economic importance because of the high potentially available protein and energy contents. Mustakas et al. (1964) reported that extruded full-fat soybean flour for human consumption was superior to good quality commercial full-fat soybean flour in terms of growth and feed efficiency in chicks. It was later shown by White et al. (1967) that infrared cooking, autoclaving and extrusion processes offered means by which full-fat soybeans may be incorporated into chick diets without adversely affecting performance. There is however some controversy as to whether utilization of unheated soybean by the chick is dependent on the physiological development of the proteolytic enzyme systems with age as proposed by Alumot and Nitsan (1961) or that unheated soybean is inferior to properly heat treated soybean because of poor availability of the amino acids (Smith and Scott, 1965). Recent investigations by Salmon and McGinnis (1968) do not subscribe to the age dependent factor proposed by Alumot and Nitsan (1961). They found no improvement in the digestibility of unheated soybean by the chick up to 6 weeks of age although the digestibility coefficients for the unheated soybean meal were always lower than those of the heat treated meal. The present investigation was undertaken to determine the age, within the first 6 weeks of life, at which unextracted raw and extruded soybeans may be incorporated into chick diets without adversely affecting performance.
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UTILIZATION OF SOYBEANS
Experiment 1. At one day of age 900 chicks were given a standard corn-soy diet with the exception of two groups of five replicates each which received the experimental diets with raw and extruded soybeans from 1 to 7 days of age. In each successive week up to 5 weeks, two groups of five replicates each were changed from the control diet to the two experimental diets. During the last 4 days of each week total excreta were collected per replicate group for the determination of nitrogen and fat digestibilities. TABLE 1.—Composition of experimental diets
Ground corn 56.75 56.00 Soybean meal 31.00 — (solvent extracted) Raw soybeans (meal) —'40 Extruded soybeans (meal) — — Tallow 8.25 — Limestone 1.50 1.50 CaPO 4 (20%P) 1.50 1.50 Iodized salt (0.015% KI) 0.25 0.25 1 Vitamin mix 0.50 0.50 Mineral mix2 0.25 0.25 Dl,-methionine (feed grade) 0.10 0.10
56.00 — — 40 — 1.50 1.50 0.25 0.50 0.25 0.10
1 Vitamin mix provided the following per kg. of diet: vitamin A, 6,6001.U.; vitamin E, 5.5I.U., vitamin D 3 , 1,320 I.C.U.; mg./kg. diet: vitamin K, 1.1; vitamin B, 2 , .0132; choline, 748, folic acid, 1.32; pantothenic acid, 8.89; riboflavin, 6.64; niacin, 26.4; Santoquin, 125.0. 2 Mineral mix provided the following in gm./kg. of diet: manganous oxide, 52.4; zinc oxide, 50.2; copper sulfate, 7.9; ferrous oxide, 20.2.
Nitrogen and fat determinations in feed, feces and carcass were by the methods of the A.O.A.C. (1960). Energy was determined by oxygen bomb calorimetry. This procedure provided weekly comparisons of the apparent digestibility of the experimental diets up to 6 weeks of age. At the end of each weekly collection period the chicks were sacrificed and pancreas weights determined as outlined. Experiment 2. Five replicate groups of 10 chicks were placed on each of the respective diets from day of age to 42 days of age at the end of which time they were sacrificed to determine carcass composition. Estimates of the productive energy (P.E.) and nitrogen efficiency were determined for each diet from data on the carcasses. To ascertain the influence of diet and age on pancreas size an additional 3 replicate groups of 10 chicks each which received the respective diets were sacrificed at 0, 7, 14, 21, 28 and 35 days of age. Experiment 3. Five replicates of 10 chicks each were fed the control diet from day of age to 7, 14, 21 and 28 days of age respectively at these various ages they were changed to the raw and extruded soybean diets which they received until they were 42 days of age. Weekly body weights, feed consumption, and pancreas weight at the termination of the experiment, were determined. RESULTS Experiment 1. There was a significant depression in body weight gain (which was more marked for the raw versus the extruded soybeans) when the birds were changed from the control diet to the experimental diets at 7, 14, 21, 28 and 35 days of age (Table 2). The weight loss was more marked with the chicks that were changed
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weight and feed consumption were determined at weekly intervals. At specified times in each of the experimental periods chicks in the respective replicate groups were sacrificed by severing the cervical vertebra and their pancreas excised and wet-weighed immediately. The data in all experiments were analyzed for variance with significant differences between treatment means determined by the Duncan's multiple range test as outlined by Steel and Torrie (1960).
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A. S. WOOD, J. D. SUMMERS, E. T. MORAN, JR. AND W. F. PEPPER
TABLE 2.—The effect of age at which chicks are changed from control diet to raw and extruded full-fat soybean supplemented diets {data on first week of changeover) Age (weeks) at time of slaughter Diets Weight gain: Control Raw soy Extruded soy
1
2
3
32.7a* 18.7b 27.5a
64.7a 33.5b 54.4a
82.3a 32.0b 73.8a
6
5
4 78.2a -15.1b 65.1a
87.7a -63.7b 70.0a
102.6a -1.78b 103.3a
1.46a 2.23b 1.79ab
1.60a 2.56b 2.05ab
2.44a 4.10b 2.12a
3.02a
2.24a
2.56a
2.95a
3.18a
2.61a
Pancreas wt. mg./g.: Control Raw soy Extruded soy
4.41a 5.82c 5.69b
4.94a 9.94c 6.48b
4.36a 8.35c 5.67b
4.22a 6.09b 5.50b
3.79a 4.41b 4.54b
3.18a 5.83c 4.07b
a-c Values with the same letter are not significantly different at P = 0.05.
over at 3 and 4 weeks of age. Sensitivity to the raw soybeans was demonstrated by poor growth and also a refusal to eat. Appetite became progressively worse with the age at which the chicks were changed from the control to raw soybean diet (up to 5 weeks of age). Sensitivity was maximal between 3 to S weeks of age and therefore suggests an age dependent function. The feed to gain ratios were significantly poorer for chicks receiving the raw soybeans than those receiving extruded soybean or the control diet. Irrespective of age at which chicks were changed from the control diet to diets with raw or extruded soybeans within the first 6 weeks of life, there was a significant difference in pancreas weight between the dietary groups (control < extruded < raw soybean meals—Table 2). The extrusion process therefore reduced the effect of trypsin inhibition but the level was not as low as that found in solvent extracted soybean meal. The digestibility of fat in the diet of the extruded soybeans was greater than that of the control or the diet with raw soybeans (Table 3). There was a common trend among the diets for a lower coefficient of
digestibility between 3 and 4 weeks of age which is consistent with the weight gain pattern. The coefficients of fat digestibility of the diet with raw soybean over the 6 week period followed a similar pattern to that of the other diets, although of slightly lower values. Experiment 2. There was no significant difference in feed intake between the chicks receiving the control and the diet with extruded soybeans (Table 4). Feed intake of the raw soybean supplemented diet was however significantly (P < .05) lower than either of the other diets throughout the 6 week period. This represented a decrease of 20 to 30% intake when compared with the other diets. The weight gain pattern indicated that chicks receiving the raw TABLE 3.—-Influence of changing from control diet at different ages to raw and extruded soybean supplemented diets on fat digestibility Digestibility coefficients (%) Age in weeks
Diets 1 Control Raw soy Extruded soy
74.1b* 93.3a 76.3b 89.5b 86.3a 92.9a
69.0b 80.8a 80.4a
64.8b 93.1a 89.3a 78.8a 85.3b 89.6a 83.8a 91.5a 91.8a
* a-c Values with the same letter are not significantly different at P =0.05.
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Feed/Gain: Control Raw soy Extruded soy
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UTILIZATION OF SOYBEANS TABLE 4.—Length of feeding period of raw and extruded soybean supplemented diets on utilization by chicks up to 6 weeks of age Age (weeks) Diets 1
2
3
4
5
6
40.3a* 33.3b 41.3a
106.0a 83.7b 102.1a
145.5a 124.9b 139.4a
188.1a 134.5b 182.0a
220.5a 171.2b 219.3a
243.6a 186.3b 251.9a
Weight gain: Control Raw soy Extruded soy
19.3a 6.0b 19.3a
52.2a 25.9c 48.4b
74.4a 37.3c 65.1b
88.8a 42.6b 79.5a
87.8a 50.3b 84.7a
105.3a 66.6c 80.5b
Feed /Gain: Control Raw soy Extruded soy
2.17a 3.13b 2.41a
2.04a 3.26b 2.12a
1.96a 3.36b 2.14a
2.12a 3.18c 2.29b
2.52a 3.36b 2.59a
2.31a 2.79b 3.15b
Pancreas wt. mg./g.: Control Raw soy Extruded soy
5.02a 5.46a 5.29a
5.42a 9.83c 6.61b
4.88a 10.30c 6.28b
4.29a 9.64b 4.36a
3.72a 8.70c 4.69b
3.26a 7.32c 4.23b
* a-c Values with the same letter are not significantly different at P = 0.05.
soybean resulted in only 30 to 50% of the growth rate of those on the other two dietary treatments up to 4 weeks of age after which the rate increased to approximately 60 percent. When the growth data of Tables 2 and 4 are compared it will be observed that the one-week exposure to raw soybeans, after receiving the control diet, resulted in drastic weight losses as of week 3. Whereas when raw soybeans were fed continuously from day old to 6 weeks of age there was an apparent adaptation to the diet. Using pancreas weight as indices of sensitivity and adaptation to the raw soybean diet, it is apparent that sensitivity declined as of 4 weeks of age (Table 2). Whereas, in terms of adaptation, the pancreas did not return to a normal proportion of body weight up to 6 weeks of age when chicks received the raw soybean diet continuously. There was a significantly lower nitrogen efficiency for the diet with raw soybean versus the control and extruded soybean diets (Table 6). However, the efficiency of
metabolizable energy was not affected by the diet fed although efficiencies of the raw and extruded soybeans were slightly lower than the control (Table 6). Experiment 3. Growth was adversely affected when chicks were changed over from the control diet at 1, 2, 3 or 4 weeks of age and fed the diet with raw soybeans continuously up to 6 weeks of age or fed continuously from day of age to 6 weeks of age (Table 5). Appetite was affected as reflected in the lower (P < .05) feed intake and high feed to gain ratios. It took approximately 5 weeks for the feed to gain ratio of chicks receiving the diet with raw soybeans from day of age to be similar to those on extruded soybeans. Whereas changing over from control to raw soybean diet at 1 and 2 weeks of age resulted in no significant difference in feed to gain ratios between raw and extruded soybean diets after 14 and 7 days respectively. The varying responses to age at time of dietary change-over from control to the 2 diets
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Feed Intake: g./wk. Control Raw soy Extruded soy
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A. S. WOOD, J. D. SUMMERS, E. T. MORAN, JR. AND W. F. PEPPER
TABLE 5.—Influence ofchanging from control diet at different ages to raw and extrttded soybean supplemented diets on feed'.gain ratio and body weight gain per week Age (weeks) at time of slaughter Diets F/G Control 2.06a* Raw soy 2.58b Extruded soy 2.03ab
F/G
Wt.
F/G
Wt.
F/G
Wt.
F/G
Wt.
64.7a 33.5c 51.9b
2.10a 5.64b 2.35a
82.3a 17.8c 61.3b
2.16a 3.52b 2.42a
78.2a 39.1b 74.8a
2.24a 3.51b 2.55a
87.7a 45.4b 81.8a
2.56a 3.09a 2.66a
102.6a 63.1b 91.7a
2.10a 7.21b 2.19a
82.3a 16.2c 61.7b
2.16a 3.27b 2.73a
78.2a 39.3c 69.0b
2.24a 2.84b 2.63b
87.7a 58.5a 79.1b
2.56a 2.74a 2.90a
102.6a 71.1b 87.3ab
2.19a
78.2a -2.3c 64.5b
2.24a 2.61a 2.61a
87.7a 42.7b 83.8a
2.56a 3.04b 2.79ab
102.6a 63.6c 88.2b
2.56a 3.36b 2.93a
102.6a 60.3c 84.2b
Control Raw soy Extruded soy Control Raw soy Extruded soy
2.65a
87.7a -10.0b 73.5a 2.99a 2.24a
Control Raw soy Extruded soy
' a-c Values with the same letter are not significantly different at P=0.05.
from day of age to 4 weeks of age validate the appetite and weight loss responses observed in Experiment 1. It is also of interest that the time required after change-over to achieve similar feed to gain ratios between raw and extruded soybean diets became progressively shorter with age. The carcass data in Table 7 indicate that feeding a diet with raw soybeans significantly (P < .05) reduced the fat free dry matter and subsequently the total carcass nitrogen content at 6 weeks of age. However, there was no difference in the dry matter, fat and nitrogen on a percentage basis in the carcasses when the dietary TABLE 6.—Effect of dietary inclusion of raw and extruded soybean on the efficiency of nitrogen and energy utilization by the chick up to 6 weeks of age
Diets Control Raw soy Extruded soy
groups were compared. These observations verify the data in Table 3 that only nitrogen efficiency is adversely affected when the diet includes raw soybeans. This depletion in nitrogen is accounted for by the poor appetite, weight loss and poor utilization of nitrogen between 2 to 4 weeks of age due to the antitryptic factor. DISCUSSION
From the results of the present experiments two physiological factors were affected namely, appetite and nitrogen utilization with its associated phasic pancreatic hypertrophy. According to Liener (19S3) it TABLE 7.—Mean carcass parameters of chicks receiving diets with unexlracied raw and extruded soybean from day of age to 6 weeks Diets
Nitrogen corrected M.E. /gram Kcal.
Nitrogen1 efficiency %
M.E.2 efficiency %
Production energy Cal/gr
3.19a* 2.92b 3.18a
27.8a 20.9b 26.4a
23.27a 21.40a 21.44a
742 625 682
1 (Gain in carcass N _g./N intake g.) X100 adjusted by covariance to a common nitrogen intake. 2 (Kilocalories gained/kilocalories M.E. intake) X100, adjusted by covariance to a common M.E. intake. * a-b Values with the same letter are not significantly different at P =0.05.
Parameters Initial weight, (g.) Final weight (g.) Dry matter (%) Fat (%) Nitrogen (%) Fat free dry matter (g.).) Total nitrogen fat free Carcass (g.)
Control
Raw
Extruded
41.0 471.7a' 34.4a 35.7a 8.9a 945.5a
41.0 272.0c 33.3a 34.2ab 9.0a 506.5b
40.9 420.7b 34.2a 33.6b 9.2a 861.5a
84.0a
45.8b
* a-b Values with the same letter are not significantly dif • ferent at P =0.05.
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Wt.
UTILIZATION OF SOYBEANS
study, both dry matter and calorie intake of the control and extruded soybean diets were similar with the only major observable difference in response being a larger pancreas (P < .05) among chicks receiving the latter diet. As noted earlier this occurrence would suggest that the heat treatment received during the extrusion process was insufficient to completely reduce the antitryptic factors to innocuous levels. Based on these data, the extra response observed by White et al. (1967) as a result of pelleting is not necessarily due to increased diet density per se but more than likely the consequence of further heat treatment effected by the pelleting process. The ability of steam pelleting to denature and facilitate the digestion of native vegetable protein has been shown with another legume seed, namely field peas, Moran and Summers (1970). The metabolizable energy efficiencies (Table 6) provide information on the overall efficiency of the diets for which there were no differences (P > .05) between diets up to 6 weeks of age. However, when nitrogen efficiency was partitioned out, the utilization of the diet with raw soybeans was poorer. This behaviour suggests that the utilization of nitrogen is the only factor detrimentally affecting the feeding value of raw soybean meal whereas the utilization of fat is satisfactory. Fat digestibility followed a negative quadratic pattern with age irrespective of diet. This may account for some of the discrepancies reported in the digestibility coefficients (Nesheim et al., 1961; White et al., 1967) as to whether they are declining or improving with age depending on what stage of the 6 week period they are observed. Therefore the depression in fat digestibility of raw soybean meal diet reported by White et al. (1967) does not appear to be solely a function of diet but could be the consequence of early physiological adjustments by the chick. In this
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was estimated that one half the growth depression associated with the ingestion of raw soybeans was due to the toxic protein soyin which interferes with the normal appetite of rats. Haines and Lyman (1961) confirmed this observation. According to the data in Table 2, the young chick receiving a diet with raw soybeans at any time between day of age and 3 weeks of age, both appetite depression and antitryptic factors are at work. Whereas, as of 4 weeks of age the sensitivity to pancreatic hypertrophy had declined and feed intake became more a function of appetite. Therefore, the increased sensitivity (weight loss) as of 4 weeks onwards was attributed to suppression of appetite since there was not subsequent evidence of sensitivity to pancreatic hypertrophy. Such a phenomena could therefore be interpreted to be both a function of low feed intake or a decline in sensitivity with age. The latter interpretation would be in disagreement with reports by Bornstein and Lipstein (1963) who reported that age has no effect on the degree of sensitivity to the inhibitory properties of raw soybean meal. It is interesting to observe that irrespective of age at which a dietary changeover was made, the rate of gain achieved at 6 weeks of age was relatively constant for both experimental diets (Tables 2,4 and 5). If the theory of feed intake to meet caloric requirement is correct, then it is apparent that the extrusion process inactivated the soyin inhibitory principle on appetite since there were no differences in intake between the extruded soybean and the control diets. The slightly lower weight gains observed in chicks receiving the extruded soybean versus the control diet agrees with observations of White et al. (1967). These workers found that pellating extruded soybean mash diets resulted in an improved live performance which they attributed to a reduction in bulkiness of the ration. In this
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A. S. WOOD, J. D. SUMMERS, E. T. MORAN, JR. AND W. F. PEPPER
SUMMARY
Studies were carried out with White Leghorn male chicks, to determine the least critical age at which unextracted raw and extruded full-fat soybeans may be incorporated in the diet up to 6 weeks of age, without adverse effects on performance. The pattern of nitrogen and fat digestibility, pancreas weight and feed to gain ratio up to 6 weeks of age were determined a) when the chicks were fed the diets continuously from day of age and b) were changed at 7, 14, 21, 28 and 35 days of age from a control onto the experimental diets. Chicks receiving the raw soybean diet versus the extruded soybean and control diets, showed a significantly poorer body weight gain throughout the 6 week period. A similar pattern occurred when chicks were changed from the control to the experimental diets at the varying ages up to 5 weeks of age. Sensitivity to the raw soybeans in terms of feed refusal when dietary changes were made, was maximal between 3 and 5 weeks of age. Irrespective of age at which chicks were changed from the control to experimental diets there were differences in pancreas
weight (control < extruded < raw soybeans) . Fat digestibility was greater for the diet with extruded soybeans than the control or raw soybean diets. There were similar metabolizable energy efficiencies for the respective diets although the nitrogen efficiency for the new raw soybean diet was the poorest. It was concluded that the poor nitrogen utilization and appetite depression resulting from raw soybean intake did not favor its inclusion before 4 weeks of age, whereas extruded soybeans were well utilized from day of age. ACKNOWLEDGEMENTS
This work was supported by the Ontario Department of Agriculture and Food. REFERENCES Alumot, E., and Z. Nitsan, 1961. The influence of soybean antitrypsin on the intestinal proteolysis of the chick. J. Nutr. 73 : 71-77. Association of Official Agricultural Chemists, 1960. Official Methods of Analysis (9th Ed.), Washington, D.C. Bornstein, S., and B. Lipstein, 1963. The influence of age of chicks on their sensitivity to raw soybean oil meal. Poultry Sci. 42: 61-69. Haines, P. C , and R. L. Lyman, 1961. Relationship of pancreatic enzyme secretion to growth inhibition in rats fed soybean trypsin inhibitor. J. Nutr. 74: 44S-4S2. Liener, I. E., 1953. Soyin, a toxic protein from the soybean. I. Inhibition of rat growth. J. Nutr. 49: 527-539. Mustakas, G. C , E. L. Griffin, Jr., L. E. Allen and O. B. Smith, 1964. Production and nutritional evaluation of extrusion-cooked full fat soybean flour. J. Am. Oil Chemists Soc. 4 1 : S97-614. Moran, E. T., Jr., and J. D. Summers, 1970. Feed processing and nutrient availability. Proc. Minnesota Nutrition Conference, pp. 73-83. Nesheim, M. C , S. Brambila and D. T. Hopkins, 1961. The effect of raw soybeans on fat digestibility in the young chick. Fed. Proc. 20: 368373. Salmon, A. J., and J. McGinnis, 1968. Digestibility of autoclaved soybean meal after temporal adaptation of chicks to unheated soybean meal. Poultry Sci. 57 : 1508-1513. Smith, R. E., and H. M. Scott, 1965. Use of free
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study, as of 3 weeks of age the digestibility coefficients of fat in the diets with raw and extruded soybeans respectively were similar. Earlier difference may be attributed to the improved availability of fat in the extruded soybeans because of the extrusion process (White et al., 1967). On the basis of the foregoing it may be concluded that the combined poor utilization of nitrogen and the depressing effect on appetite when raw soybeans are included in a diet does not favor its incorporation before 4 weeks of age. The extrusion process to the soybeans made it similar in utilization to extracted soybeans with the exception of a slight pancreatic hypertrophy between day of age and 3 weeks of age.
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UTILIZATION OF SOYBEANS amino acid concentrations in blood plasma in evaluating the amino acid adequacy of intact proteins for growth. II. Free amino acid patterns of blood plasma of chicks fed sesame and raw, heated and overheated soybean meals. J. Nutr. 86: 45-50. Steel, R. G., and J. H. Torrie, 1960. Principles and
Procedures of Statistics. McGraw-Hill Book Co., New York. White, C. L., D. E. Greene, P. W. Waldroup and E. L. Stephenson, 1967. The use of unextracted soybeans for chicks. 1. Comparison of infrared cooked, autoclaved and extruded soybeans. Poultry Sci. 56: 1180-1185.
LAWRENCE R. BERG AND W. W. LAWRENCE Washington State University, Western Washington Research and Extension Center, Puyallup, Washington 98371 (Received for publication February 22, 1971)
P
REVIOUS results from this laboratory (Berg, 1966) showed that 20 p.p.m. vanadium added to a corn-soybean meal chick diet caused a growth depression of 25-30% whereas a similar addition of vanadium to a corn-fish meal diet depressed growth only 3-7%. By contrast, when 20 p.p.m. vanadium was added to a sucrosefish meal diet, growth was depressed by 5Q% and high mortality resulted. Adding graded levels of corn to the sucrose-fish meal ration and fish meal to the corn-soybean ration reduced vanadium toxicity. Reports of other dietary factors which may affect vanadium toxicity were previously reviewed (Berg, 1966). Hudson (1964) reviewed the toxicology of vanadium as it pertains to such mammals as rats, mice, guinea pigs, rabbits, dog and man. Little or no reference was made to studies involving birds. Of pertinence to this paper was the reference to studies indicating that vanadium toxicity was counteracted by subcutaneous injections of ascorbic acid. The experiments described in this paper 1 Scientific paper No. 3635, Washington Agricultural Experiment Stations, Pullman, Project No. 1748.
will present evidence to show that dietary cottonseed meal, dehydrated grass and ascorbic acid prevents the toxic effects associated with oral consumption of vanadium by chicks. EXPERIMENTAL
Composition of the sucrose-fish meal basal ration used in all studies is presented in Table 1. Substitutions in the basal ration were made at the expense of sucrose. Two groups of ten White Leghorn cockerel chicks were used in all experiments to test each treatment. All experiments were conducted in wire floored battery brooders. Feed and water were supplied ad libitum. TABLE 1.—Composition of basal diet Ingredient 1 Sucrose Herring fish meal Tricalcium phosphate Iodized salt Tallow
% of diet 65.84 30.56 .30 .30 3.00
1 The following were added per kg of ration: 5000 I.U. vitamin A, 750 I.C.U. vitamin D 3 , 4 mg. menadione sodium bisulfite, 12.5 I.U. vitamin E, 5 mg. riboflavin, 12.5 mg. calcium pantothenate, 30 mg. niacin, 5 mg. pyridoxine, 7.5 mg. thiamin, 1320 mg. choline chloride, 11 meg. vitamin B12, 1 mg. folic acid, 120 mg. ethoxyquin, 310 mg. MnSO<, 100 mg. ZnO, 4.2 mg. Cu as CuCOs and 20 mg. Fe as FeSCvH 2 0.
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Cottonseed Meal, Dehydrated Grass and Ascorbic Acid as Dietary Factors Preventing Toxicity of Vanadium for the Chick1
Department of Poultry Science, University of Guelph, Guelph, Ontario, Canada (Received for publication February 19, 1971)
T
EXPERIMENTAL PROCEDURE
Three experiments were carried out to compare the utilization of a standard cornsoy diet versus unextracted raw and extruded soybean supplemented diets. Extrusion process. Whole soybeans were hammer milled prior to the extrusion process (Wenger X-1S0 model extruder).1 In essence, the ground whole soybean meal was passed through a preconditioner where 30-40 lb. steam was introduced into the meal raising the temperature to 210°F. subsequent to being fed into the extruder. The extruder is a closed tapered barrel with a revolving screw and a narrow diehead opening at one end. The screw extrudes the material through the die-head opening where a combination of temperature of the material and friction result in an extrusion temperature of 2SS°F. As the cooked fullfat meal emerges from the extruder a fast reduction of pressure occurs which causes the material to expand rapidly and rupture most of the oil cells. Day-old White Leghorn male chicks were used in the experiments, were weighed at day of age and randomly assigned to pens on the basis of body weight. Five replicate groups of 10 chicks each were fed the experimental diets (Table 1) from 1 to 42 days of age. The chicks were reared in electrically heated battery brooders in which the experimental diets (in mash form) and tap water were supplied ad libitum. Body 1
Wenger Manufacturing, Kansas City, Mo. 64112, U.S.A.
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HE use of full-fat soybean in poultry diets is of economic importance because of the high potentially available protein and energy contents. Mustakas et al. (1964) reported that extruded full-fat soybean flour for human consumption was superior to good quality commercial full-fat soybean flour in terms of growth and feed efficiency in chicks. It was later shown by White et al. (1967) that infrared cooking, autoclaving and extrusion processes offered means by which full-fat soybeans may be incorporated into chick diets without adversely affecting performance. There is however some controversy as to whether utilization of unheated soybean by the chick is dependent on the physiological development of the proteolytic enzyme systems with age as proposed by Alumot and Nitsan (1961) or that unheated soybean is inferior to properly heat treated soybean because of poor availability of the amino acids (Smith and Scott, 1965). Recent investigations by Salmon and McGinnis (1968) do not subscribe to the age dependent factor proposed by Alumot and Nitsan (1961). They found no improvement in the digestibility of unheated soybean by the chick up to 6 weeks of age although the digestibility coefficients for the unheated soybean meal were always lower than those of the heat treated meal. The present investigation was undertaken to determine the age, within the first 6 weeks of life, at which unextracted raw and extruded soybeans may be incorporated into chick diets without adversely affecting performance.
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UTILIZATION OF SOYBEANS
Experiment 1. At one day of age 900 chicks were given a standard corn-soy diet with the exception of two groups of five replicates each which received the experimental diets with raw and extruded soybeans from 1 to 7 days of age. In each successive week up to 5 weeks, two groups of five replicates each were changed from the control diet to the two experimental diets. During the last 4 days of each week total excreta were collected per replicate group for the determination of nitrogen and fat digestibilities. TABLE 1.—Composition of experimental diets
Ground corn 56.75 56.00 Soybean meal 31.00 — (solvent extracted) Raw soybeans (meal) —'40 Extruded soybeans (meal) — — Tallow 8.25 — Limestone 1.50 1.50 CaPO 4 (20%P) 1.50 1.50 Iodized salt (0.015% KI) 0.25 0.25 1 Vitamin mix 0.50 0.50 Mineral mix2 0.25 0.25 Dl,-methionine (feed grade) 0.10 0.10
56.00 — — 40 — 1.50 1.50 0.25 0.50 0.25 0.10
1 Vitamin mix provided the following per kg. of diet: vitamin A, 6,6001.U.; vitamin E, 5.5I.U., vitamin D 3 , 1,320 I.C.U.; mg./kg. diet: vitamin K, 1.1; vitamin B, 2 , .0132; choline, 748, folic acid, 1.32; pantothenic acid, 8.89; riboflavin, 6.64; niacin, 26.4; Santoquin, 125.0. 2 Mineral mix provided the following in gm./kg. of diet: manganous oxide, 52.4; zinc oxide, 50.2; copper sulfate, 7.9; ferrous oxide, 20.2.
Nitrogen and fat determinations in feed, feces and carcass were by the methods of the A.O.A.C. (1960). Energy was determined by oxygen bomb calorimetry. This procedure provided weekly comparisons of the apparent digestibility of the experimental diets up to 6 weeks of age. At the end of each weekly collection period the chicks were sacrificed and pancreas weights determined as outlined. Experiment 2. Five replicate groups of 10 chicks were placed on each of the respective diets from day of age to 42 days of age at the end of which time they were sacrificed to determine carcass composition. Estimates of the productive energy (P.E.) and nitrogen efficiency were determined for each diet from data on the carcasses. To ascertain the influence of diet and age on pancreas size an additional 3 replicate groups of 10 chicks each which received the respective diets were sacrificed at 0, 7, 14, 21, 28 and 35 days of age. Experiment 3. Five replicates of 10 chicks each were fed the control diet from day of age to 7, 14, 21 and 28 days of age respectively at these various ages they were changed to the raw and extruded soybean diets which they received until they were 42 days of age. Weekly body weights, feed consumption, and pancreas weight at the termination of the experiment, were determined. RESULTS Experiment 1. There was a significant depression in body weight gain (which was more marked for the raw versus the extruded soybeans) when the birds were changed from the control diet to the experimental diets at 7, 14, 21, 28 and 35 days of age (Table 2). The weight loss was more marked with the chicks that were changed
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weight and feed consumption were determined at weekly intervals. At specified times in each of the experimental periods chicks in the respective replicate groups were sacrificed by severing the cervical vertebra and their pancreas excised and wet-weighed immediately. The data in all experiments were analyzed for variance with significant differences between treatment means determined by the Duncan's multiple range test as outlined by Steel and Torrie (1960).
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A. S. WOOD, J. D. SUMMERS, E. T. MORAN, JR. AND W. F. PEPPER
TABLE 2.—The effect of age at which chicks are changed from control diet to raw and extruded full-fat soybean supplemented diets {data on first week of changeover) Age (weeks) at time of slaughter Diets Weight gain: Control Raw soy Extruded soy
1
2
3
32.7a* 18.7b 27.5a
64.7a 33.5b 54.4a
82.3a 32.0b 73.8a
6
5
4 78.2a -15.1b 65.1a
87.7a -63.7b 70.0a
102.6a -1.78b 103.3a
1.46a 2.23b 1.79ab
1.60a 2.56b 2.05ab
2.44a 4.10b 2.12a
3.02a
2.24a
2.56a
2.95a
3.18a
2.61a
Pancreas wt. mg./g.: Control Raw soy Extruded soy
4.41a 5.82c 5.69b
4.94a 9.94c 6.48b
4.36a 8.35c 5.67b
4.22a 6.09b 5.50b
3.79a 4.41b 4.54b
3.18a 5.83c 4.07b
a-c Values with the same letter are not significantly different at P = 0.05.
over at 3 and 4 weeks of age. Sensitivity to the raw soybeans was demonstrated by poor growth and also a refusal to eat. Appetite became progressively worse with the age at which the chicks were changed from the control to raw soybean diet (up to 5 weeks of age). Sensitivity was maximal between 3 to S weeks of age and therefore suggests an age dependent function. The feed to gain ratios were significantly poorer for chicks receiving the raw soybeans than those receiving extruded soybean or the control diet. Irrespective of age at which chicks were changed from the control diet to diets with raw or extruded soybeans within the first 6 weeks of life, there was a significant difference in pancreas weight between the dietary groups (control < extruded < raw soybean meals—Table 2). The extrusion process therefore reduced the effect of trypsin inhibition but the level was not as low as that found in solvent extracted soybean meal. The digestibility of fat in the diet of the extruded soybeans was greater than that of the control or the diet with raw soybeans (Table 3). There was a common trend among the diets for a lower coefficient of
digestibility between 3 and 4 weeks of age which is consistent with the weight gain pattern. The coefficients of fat digestibility of the diet with raw soybean over the 6 week period followed a similar pattern to that of the other diets, although of slightly lower values. Experiment 2. There was no significant difference in feed intake between the chicks receiving the control and the diet with extruded soybeans (Table 4). Feed intake of the raw soybean supplemented diet was however significantly (P < .05) lower than either of the other diets throughout the 6 week period. This represented a decrease of 20 to 30% intake when compared with the other diets. The weight gain pattern indicated that chicks receiving the raw TABLE 3.—-Influence of changing from control diet at different ages to raw and extruded soybean supplemented diets on fat digestibility Digestibility coefficients (%) Age in weeks
Diets 1 Control Raw soy Extruded soy
74.1b* 93.3a 76.3b 89.5b 86.3a 92.9a
69.0b 80.8a 80.4a
64.8b 93.1a 89.3a 78.8a 85.3b 89.6a 83.8a 91.5a 91.8a
* a-c Values with the same letter are not significantly different at P =0.05.
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Feed/Gain: Control Raw soy Extruded soy
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UTILIZATION OF SOYBEANS TABLE 4.—Length of feeding period of raw and extruded soybean supplemented diets on utilization by chicks up to 6 weeks of age Age (weeks) Diets 1
2
3
4
5
6
40.3a* 33.3b 41.3a
106.0a 83.7b 102.1a
145.5a 124.9b 139.4a
188.1a 134.5b 182.0a
220.5a 171.2b 219.3a
243.6a 186.3b 251.9a
Weight gain: Control Raw soy Extruded soy
19.3a 6.0b 19.3a
52.2a 25.9c 48.4b
74.4a 37.3c 65.1b
88.8a 42.6b 79.5a
87.8a 50.3b 84.7a
105.3a 66.6c 80.5b
Feed /Gain: Control Raw soy Extruded soy
2.17a 3.13b 2.41a
2.04a 3.26b 2.12a
1.96a 3.36b 2.14a
2.12a 3.18c 2.29b
2.52a 3.36b 2.59a
2.31a 2.79b 3.15b
Pancreas wt. mg./g.: Control Raw soy Extruded soy
5.02a 5.46a 5.29a
5.42a 9.83c 6.61b
4.88a 10.30c 6.28b
4.29a 9.64b 4.36a
3.72a 8.70c 4.69b
3.26a 7.32c 4.23b
* a-c Values with the same letter are not significantly different at P = 0.05.
soybean resulted in only 30 to 50% of the growth rate of those on the other two dietary treatments up to 4 weeks of age after which the rate increased to approximately 60 percent. When the growth data of Tables 2 and 4 are compared it will be observed that the one-week exposure to raw soybeans, after receiving the control diet, resulted in drastic weight losses as of week 3. Whereas when raw soybeans were fed continuously from day old to 6 weeks of age there was an apparent adaptation to the diet. Using pancreas weight as indices of sensitivity and adaptation to the raw soybean diet, it is apparent that sensitivity declined as of 4 weeks of age (Table 2). Whereas, in terms of adaptation, the pancreas did not return to a normal proportion of body weight up to 6 weeks of age when chicks received the raw soybean diet continuously. There was a significantly lower nitrogen efficiency for the diet with raw soybean versus the control and extruded soybean diets (Table 6). However, the efficiency of
metabolizable energy was not affected by the diet fed although efficiencies of the raw and extruded soybeans were slightly lower than the control (Table 6). Experiment 3. Growth was adversely affected when chicks were changed over from the control diet at 1, 2, 3 or 4 weeks of age and fed the diet with raw soybeans continuously up to 6 weeks of age or fed continuously from day of age to 6 weeks of age (Table 5). Appetite was affected as reflected in the lower (P < .05) feed intake and high feed to gain ratios. It took approximately 5 weeks for the feed to gain ratio of chicks receiving the diet with raw soybeans from day of age to be similar to those on extruded soybeans. Whereas changing over from control to raw soybean diet at 1 and 2 weeks of age resulted in no significant difference in feed to gain ratios between raw and extruded soybean diets after 14 and 7 days respectively. The varying responses to age at time of dietary change-over from control to the 2 diets
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Feed Intake: g./wk. Control Raw soy Extruded soy
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A. S. WOOD, J. D. SUMMERS, E. T. MORAN, JR. AND W. F. PEPPER
TABLE 5.—Influence ofchanging from control diet at different ages to raw and extrttded soybean supplemented diets on feed'.gain ratio and body weight gain per week Age (weeks) at time of slaughter Diets F/G Control 2.06a* Raw soy 2.58b Extruded soy 2.03ab
F/G
Wt.
F/G
Wt.
F/G
Wt.
F/G
Wt.
64.7a 33.5c 51.9b
2.10a 5.64b 2.35a
82.3a 17.8c 61.3b
2.16a 3.52b 2.42a
78.2a 39.1b 74.8a
2.24a 3.51b 2.55a
87.7a 45.4b 81.8a
2.56a 3.09a 2.66a
102.6a 63.1b 91.7a
2.10a 7.21b 2.19a
82.3a 16.2c 61.7b
2.16a 3.27b 2.73a
78.2a 39.3c 69.0b
2.24a 2.84b 2.63b
87.7a 58.5a 79.1b
2.56a 2.74a 2.90a
102.6a 71.1b 87.3ab
2.19a
78.2a -2.3c 64.5b
2.24a 2.61a 2.61a
87.7a 42.7b 83.8a
2.56a 3.04b 2.79ab
102.6a 63.6c 88.2b
2.56a 3.36b 2.93a
102.6a 60.3c 84.2b
Control Raw soy Extruded soy Control Raw soy Extruded soy
2.65a
87.7a -10.0b 73.5a 2.99a 2.24a
Control Raw soy Extruded soy
' a-c Values with the same letter are not significantly different at P=0.05.
from day of age to 4 weeks of age validate the appetite and weight loss responses observed in Experiment 1. It is also of interest that the time required after change-over to achieve similar feed to gain ratios between raw and extruded soybean diets became progressively shorter with age. The carcass data in Table 7 indicate that feeding a diet with raw soybeans significantly (P < .05) reduced the fat free dry matter and subsequently the total carcass nitrogen content at 6 weeks of age. However, there was no difference in the dry matter, fat and nitrogen on a percentage basis in the carcasses when the dietary TABLE 6.—Effect of dietary inclusion of raw and extruded soybean on the efficiency of nitrogen and energy utilization by the chick up to 6 weeks of age
Diets Control Raw soy Extruded soy
groups were compared. These observations verify the data in Table 3 that only nitrogen efficiency is adversely affected when the diet includes raw soybeans. This depletion in nitrogen is accounted for by the poor appetite, weight loss and poor utilization of nitrogen between 2 to 4 weeks of age due to the antitryptic factor. DISCUSSION
From the results of the present experiments two physiological factors were affected namely, appetite and nitrogen utilization with its associated phasic pancreatic hypertrophy. According to Liener (19S3) it TABLE 7.—Mean carcass parameters of chicks receiving diets with unexlracied raw and extruded soybean from day of age to 6 weeks Diets
Nitrogen corrected M.E. /gram Kcal.
Nitrogen1 efficiency %
M.E.2 efficiency %
Production energy Cal/gr
3.19a* 2.92b 3.18a
27.8a 20.9b 26.4a
23.27a 21.40a 21.44a
742 625 682
1 (Gain in carcass N _g./N intake g.) X100 adjusted by covariance to a common nitrogen intake. 2 (Kilocalories gained/kilocalories M.E. intake) X100, adjusted by covariance to a common M.E. intake. * a-b Values with the same letter are not significantly different at P =0.05.
Parameters Initial weight, (g.) Final weight (g.) Dry matter (%) Fat (%) Nitrogen (%) Fat free dry matter (g.).) Total nitrogen fat free Carcass (g.)
Control
Raw
Extruded
41.0 471.7a' 34.4a 35.7a 8.9a 945.5a
41.0 272.0c 33.3a 34.2ab 9.0a 506.5b
40.9 420.7b 34.2a 33.6b 9.2a 861.5a
84.0a
45.8b
* a-b Values with the same letter are not significantly dif • ferent at P =0.05.
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Wt.
UTILIZATION OF SOYBEANS
study, both dry matter and calorie intake of the control and extruded soybean diets were similar with the only major observable difference in response being a larger pancreas (P < .05) among chicks receiving the latter diet. As noted earlier this occurrence would suggest that the heat treatment received during the extrusion process was insufficient to completely reduce the antitryptic factors to innocuous levels. Based on these data, the extra response observed by White et al. (1967) as a result of pelleting is not necessarily due to increased diet density per se but more than likely the consequence of further heat treatment effected by the pelleting process. The ability of steam pelleting to denature and facilitate the digestion of native vegetable protein has been shown with another legume seed, namely field peas, Moran and Summers (1970). The metabolizable energy efficiencies (Table 6) provide information on the overall efficiency of the diets for which there were no differences (P > .05) between diets up to 6 weeks of age. However, when nitrogen efficiency was partitioned out, the utilization of the diet with raw soybeans was poorer. This behaviour suggests that the utilization of nitrogen is the only factor detrimentally affecting the feeding value of raw soybean meal whereas the utilization of fat is satisfactory. Fat digestibility followed a negative quadratic pattern with age irrespective of diet. This may account for some of the discrepancies reported in the digestibility coefficients (Nesheim et al., 1961; White et al., 1967) as to whether they are declining or improving with age depending on what stage of the 6 week period they are observed. Therefore the depression in fat digestibility of raw soybean meal diet reported by White et al. (1967) does not appear to be solely a function of diet but could be the consequence of early physiological adjustments by the chick. In this
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was estimated that one half the growth depression associated with the ingestion of raw soybeans was due to the toxic protein soyin which interferes with the normal appetite of rats. Haines and Lyman (1961) confirmed this observation. According to the data in Table 2, the young chick receiving a diet with raw soybeans at any time between day of age and 3 weeks of age, both appetite depression and antitryptic factors are at work. Whereas, as of 4 weeks of age the sensitivity to pancreatic hypertrophy had declined and feed intake became more a function of appetite. Therefore, the increased sensitivity (weight loss) as of 4 weeks onwards was attributed to suppression of appetite since there was not subsequent evidence of sensitivity to pancreatic hypertrophy. Such a phenomena could therefore be interpreted to be both a function of low feed intake or a decline in sensitivity with age. The latter interpretation would be in disagreement with reports by Bornstein and Lipstein (1963) who reported that age has no effect on the degree of sensitivity to the inhibitory properties of raw soybean meal. It is interesting to observe that irrespective of age at which a dietary changeover was made, the rate of gain achieved at 6 weeks of age was relatively constant for both experimental diets (Tables 2,4 and 5). If the theory of feed intake to meet caloric requirement is correct, then it is apparent that the extrusion process inactivated the soyin inhibitory principle on appetite since there were no differences in intake between the extruded soybean and the control diets. The slightly lower weight gains observed in chicks receiving the extruded soybean versus the control diet agrees with observations of White et al. (1967). These workers found that pellating extruded soybean mash diets resulted in an improved live performance which they attributed to a reduction in bulkiness of the ration. In this
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A. S. WOOD, J. D. SUMMERS, E. T. MORAN, JR. AND W. F. PEPPER
SUMMARY
Studies were carried out with White Leghorn male chicks, to determine the least critical age at which unextracted raw and extruded full-fat soybeans may be incorporated in the diet up to 6 weeks of age, without adverse effects on performance. The pattern of nitrogen and fat digestibility, pancreas weight and feed to gain ratio up to 6 weeks of age were determined a) when the chicks were fed the diets continuously from day of age and b) were changed at 7, 14, 21, 28 and 35 days of age from a control onto the experimental diets. Chicks receiving the raw soybean diet versus the extruded soybean and control diets, showed a significantly poorer body weight gain throughout the 6 week period. A similar pattern occurred when chicks were changed from the control to the experimental diets at the varying ages up to 5 weeks of age. Sensitivity to the raw soybeans in terms of feed refusal when dietary changes were made, was maximal between 3 and 5 weeks of age. Irrespective of age at which chicks were changed from the control to experimental diets there were differences in pancreas
weight (control < extruded < raw soybeans) . Fat digestibility was greater for the diet with extruded soybeans than the control or raw soybean diets. There were similar metabolizable energy efficiencies for the respective diets although the nitrogen efficiency for the new raw soybean diet was the poorest. It was concluded that the poor nitrogen utilization and appetite depression resulting from raw soybean intake did not favor its inclusion before 4 weeks of age, whereas extruded soybeans were well utilized from day of age. ACKNOWLEDGEMENTS
This work was supported by the Ontario Department of Agriculture and Food. REFERENCES Alumot, E., and Z. Nitsan, 1961. The influence of soybean antitrypsin on the intestinal proteolysis of the chick. J. Nutr. 73 : 71-77. Association of Official Agricultural Chemists, 1960. Official Methods of Analysis (9th Ed.), Washington, D.C. Bornstein, S., and B. Lipstein, 1963. The influence of age of chicks on their sensitivity to raw soybean oil meal. Poultry Sci. 42: 61-69. Haines, P. C , and R. L. Lyman, 1961. Relationship of pancreatic enzyme secretion to growth inhibition in rats fed soybean trypsin inhibitor. J. Nutr. 74: 44S-4S2. Liener, I. E., 1953. Soyin, a toxic protein from the soybean. I. Inhibition of rat growth. J. Nutr. 49: 527-539. Mustakas, G. C , E. L. Griffin, Jr., L. E. Allen and O. B. Smith, 1964. Production and nutritional evaluation of extrusion-cooked full fat soybean flour. J. Am. Oil Chemists Soc. 4 1 : S97-614. Moran, E. T., Jr., and J. D. Summers, 1970. Feed processing and nutrient availability. Proc. Minnesota Nutrition Conference, pp. 73-83. Nesheim, M. C , S. Brambila and D. T. Hopkins, 1961. The effect of raw soybeans on fat digestibility in the young chick. Fed. Proc. 20: 368373. Salmon, A. J., and J. McGinnis, 1968. Digestibility of autoclaved soybean meal after temporal adaptation of chicks to unheated soybean meal. Poultry Sci. 57 : 1508-1513. Smith, R. E., and H. M. Scott, 1965. Use of free
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study, as of 3 weeks of age the digestibility coefficients of fat in the diets with raw and extruded soybeans respectively were similar. Earlier difference may be attributed to the improved availability of fat in the extruded soybeans because of the extrusion process (White et al., 1967). On the basis of the foregoing it may be concluded that the combined poor utilization of nitrogen and the depressing effect on appetite when raw soybeans are included in a diet does not favor its incorporation before 4 weeks of age. The extrusion process to the soybeans made it similar in utilization to extracted soybeans with the exception of a slight pancreatic hypertrophy between day of age and 3 weeks of age.
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UTILIZATION OF SOYBEANS amino acid concentrations in blood plasma in evaluating the amino acid adequacy of intact proteins for growth. II. Free amino acid patterns of blood plasma of chicks fed sesame and raw, heated and overheated soybean meals. J. Nutr. 86: 45-50. Steel, R. G., and J. H. Torrie, 1960. Principles and
Procedures of Statistics. McGraw-Hill Book Co., New York. White, C. L., D. E. Greene, P. W. Waldroup and E. L. Stephenson, 1967. The use of unextracted soybeans for chicks. 1. Comparison of infrared cooked, autoclaved and extruded soybeans. Poultry Sci. 56: 1180-1185.
LAWRENCE R. BERG AND W. W. LAWRENCE Washington State University, Western Washington Research and Extension Center, Puyallup, Washington 98371 (Received for publication February 22, 1971)
P
REVIOUS results from this laboratory (Berg, 1966) showed that 20 p.p.m. vanadium added to a corn-soybean meal chick diet caused a growth depression of 25-30% whereas a similar addition of vanadium to a corn-fish meal diet depressed growth only 3-7%. By contrast, when 20 p.p.m. vanadium was added to a sucrosefish meal diet, growth was depressed by 5Q% and high mortality resulted. Adding graded levels of corn to the sucrose-fish meal ration and fish meal to the corn-soybean ration reduced vanadium toxicity. Reports of other dietary factors which may affect vanadium toxicity were previously reviewed (Berg, 1966). Hudson (1964) reviewed the toxicology of vanadium as it pertains to such mammals as rats, mice, guinea pigs, rabbits, dog and man. Little or no reference was made to studies involving birds. Of pertinence to this paper was the reference to studies indicating that vanadium toxicity was counteracted by subcutaneous injections of ascorbic acid. The experiments described in this paper 1 Scientific paper No. 3635, Washington Agricultural Experiment Stations, Pullman, Project No. 1748.
will present evidence to show that dietary cottonseed meal, dehydrated grass and ascorbic acid prevents the toxic effects associated with oral consumption of vanadium by chicks. EXPERIMENTAL
Composition of the sucrose-fish meal basal ration used in all studies is presented in Table 1. Substitutions in the basal ration were made at the expense of sucrose. Two groups of ten White Leghorn cockerel chicks were used in all experiments to test each treatment. All experiments were conducted in wire floored battery brooders. Feed and water were supplied ad libitum. TABLE 1.—Composition of basal diet Ingredient 1 Sucrose Herring fish meal Tricalcium phosphate Iodized salt Tallow
% of diet 65.84 30.56 .30 .30 3.00
1 The following were added per kg of ration: 5000 I.U. vitamin A, 750 I.C.U. vitamin D 3 , 4 mg. menadione sodium bisulfite, 12.5 I.U. vitamin E, 5 mg. riboflavin, 12.5 mg. calcium pantothenate, 30 mg. niacin, 5 mg. pyridoxine, 7.5 mg. thiamin, 1320 mg. choline chloride, 11 meg. vitamin B12, 1 mg. folic acid, 120 mg. ethoxyquin, 310 mg. MnSO<, 100 mg. ZnO, 4.2 mg. Cu as CuCOs and 20 mg. Fe as FeSCvH 2 0.
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Cottonseed Meal, Dehydrated Grass and Ascorbic Acid as Dietary Factors Preventing Toxicity of Vanadium for the Chick1