- Email: [email protected]
Metabolizable Energy Value and Utilization of Different Types and Grades of Fat by the Chick
Metabolizable Energy Value and Utilization of Different Types and Grades of Fat by the Chick MARION P. CULLEN, OSCAR G. RASMUSSEN AND O. H. M. WILDER Division of Animal Feeds, American Meat Institute Foundation, University of Chicago, Chicago, Illinois (Received for publication May 10, 1961)
I
T HAS been shown by Sunde (1956) and others that the presence of fat in the diet of the chicken has a beneficial effect upon the efficiency of feed utilization. Waibel (1955) and others have shown that the presence of fat in the diet frequently has a beneficial influence on growth rate also. These effects of added fat in poultry feeds have led to the development of more highly efficient feeds and emphasized the need for more precise information regarding the energy content of fats and the utilization of various types and grades of fats when fed. The energy content of poultry feed ingredients has been studied by Hill and Anderson (1958) and Potter et al. (1958), and it was shown that metabolizable energy is a more valid measure of energy content of poultry feeds than is productive energy. Metabolizable energy values ranging from 2,860 to 3,300 Calories per pound have been reported for tallow by Anderson (1955), Hill et al. (1956), Hill and Renner (1957), and Renner and Hill (1958). Potter and Matterson (1960) reported a value of 3,190 Calories per pound for tallow. The metabolizable energy value for lard was reported by Renner and Hill (1958) to be 3,980 Calories per pound and the percentage utilization of the lard was 93.4 while tallow had an energy value of 2,860 Calories per pound and utilization was only 67.0 percent. Fedde et al. (1960) studied the absorbability of fats in the chick and reported that hog grease used at Journal Paper No. 217, American Meat Institute Foundation.
a 20% level in the ration had an apparent absorption coefficient of 85.4 in chicks at 1 to 2 weeks of age and 93.0 at 7 to 8 weeks of age. In the same study, tallow absorption coefficients increased from 53 at 1 week of age to 80 at 12 weeks of age. Siedler et al. (1955) studied the effects of the addition of 3 or 6% stabilized animal fats or 3 % free fatty acids to a high energy broiler ration. The materials used were choice white grease, yellow grease, brown grease, prime tallow, No. 2 tallow and fatty acids prepared from choice white grease. These workers reported excellent utilization of choice white grease, yellow grease, brown grease or fatty acids at the 3 % level, with some reduction in calcoric efficiency when these fats were fed at the 6% level. The tallows were well utilized in the second experiment. The chicks used in the two experiments were obtained from different hatcheries and those chicks used in the second experiment grew at a more rapid rate than those in the first experiment which might suggest that the rapid growing birds are able to utilize tallow more efficiently than the slower growing birds. Renner and Hill (1960) later studied the utilization of corn oil, lard and tallow by chickens of various ages and reported that metabolizable energy and absorbability were comparable for chicks fed lard and tallow, and that age of the chick affected the utilization of tallow since absorbability of tallow ranged from 70% for chicks at 2 weeks of age to 82% for chicks at 8 weeks of age.
360
METABOLIZABLE ENERGY OF FAT
The purpose of the present study was to measure the metabolizable energy content and apparent absorbability of a number of different types and grades of fats, and the general performance of these types and grades of fats when fed to chicks in semi-practical rations. MATERIALS AND METHODS
The method used for measuring metabolizable energy was patterned after that used by Hill and Anderson (1958) except that the basal diet was formulated insofar as possible from ingredients commonly found in commercial poultry rations. Glucose (Cerelose) was used at a 14% level in the basal ration as a reference standard and was completely replaced by the test fats in experimental diets. The basal diet is shown in Table 1. Four experiments were run in measuring metabolizable energy; in some cases the measurements were repeated on the same samples and in others different samples were used. In the fourth experiment, both the semipractical and the E-9 diet of Hill and Anderson (1958) were used.
361
TABLE 1.—Composition of diets Semipractical
%
Ground yellow corn 36.73 Soybean oil meal (44% protein) 28.62 Glucose (Cerelose) 14.00 M e a t and bone meal (50% protein) 8.00 Dried brewers' yeast 4.00 Corn gluten meal 5.00 Dehydrated alfalfa meal 1.00 DL~Methionine 0.05 Pulverized limestone 0.50 Di-calcium phosphate 0.50 Iodized salt 0.50 Vitamin A & D oil (2,200 U.S.P. units A a n d 4001.C. units D / g . ) 0.25 Choline chloride (25%) 0.50 Chlortetracycline supplement (1.8 0.25 g./lb.). Trace mineral mix 0.10' Vitamin mix Test fat Ground wheat Casein (crude) Gelatin Hydrogenated vegetable fat Fish meal (menhaden) Fish solubles (dry basis) Dried whey
*
E-92
% 17.5 44.1 2.5
2.0 1.0 0.5
Practical diet
%
40.00 31.40 8.00 2.00 5.00 1.00 0.05 0.50 0.50 0.50 0.50
0.42 0.502
*
0.25 0.101 0.203 10.00
9.0 10.5 2.5 2.5 4.0 1.0 2.0
1 Supplied the following in mg. per kilogram of diet: FeS04 7H*0, 200; CuSO<-HiO 12.5; C0SO4, 2.5; ZnSOj-HzO, 10.00; and MnS0 4 , 62.5. 2 Hill and Anderson (1958). 3 Supplied per kilogram of diet: 6.6 mg. riboflavin, 13.2 mg. calcium pantothenate, 2.2 mg. menadione, 3.52 mg. pyridoxine HCI, 0.77 mg. folic acid, 0.01 mg. vit. B12, 5,000 U.S.P. units Vit. A, and 560 I.C. units Da. * Substituted for Cerelose in test diets.
used in determining intake-excretion ratios, Nitrogen was determined by the Kjeldahl method (A.O.A.C, 7th Ed;, 23.8, Day-old cockerels were obtained for 2.24 and 2.22), combustible energy by use in all experiments. In the first study Parr oxygen bomb calorimeter, chromic the chicks were Hyline cockerels and in oxide by the method described by Hill and subsequent tests, VantressX Arbor Acre Anderson (1958), dietary fat by extracWhite Rocks were used. The chicks were tion with petroleum ether, and total lipid kept in battery brooders on raised wire in excreta by extraction with petroleum floors and feed and water were supplied ether followed by acetic acid hydrolysis ad libitum. All of the chicks received the and reextraction as described by Hopkins basal diet for two weeks after which they etal. (1955). were distributed according to weight into A total of 16 different samples of fats duplicate lots of 12 chicks each. Weight were obtained from 9 different producers gain and feed consumption records.were for the metabolizable energy studies. Rekept to provide an index of the general fined corn oil was included in two of the condition of the chicks. The chicks were tests, using a new sample of a different fed their respective experimental diets for brand for the second trial. The refined two weeks, and collections of excreta were corn oil was included with the expectation made during the last week when the that it would be a relatively standardized chicks were between 3 and 4 weeks of age. reference fat. The chromic oxide indicator method was Apparent absorbability of the fats was
362
M. P. CULLEN, O. G. RASMUSSEN AND O. H. M. WILDER
studied in the third and fourth trials to provide additional information regarding utilization of the fats. Fats used in the metabolizable energy studies included choice white grease, yellow grease, brown grease, poultry fat, bleachable fancy tallow, No. 2 tallow, all-beef tallow, hydrolyzed animal and vegetable fat, fatty acid methyl ester and refined corn oil. Two additional tests were run in which chicks were fed the test fats at a level of 10% in a practical ration for an 8-week period. Duplicate lots of 16 chicks each were used in these tests. Chick weights and feed consumption records were recorded. The ration used in this test is shown in Table 1. RESULTS AND DISCUSSION
The metabolizable energy (M.E.) values are shown in Table 2. Many of the fats offered to the feed trade are mixtures having varying glyceride structures and samples of any one grade may vary from time to time which may account for some of the variation observed in the different samples tested. Choice white grease is an unrefined fat with a fatty acid composition similar to lard. The average M.E. value of 3,925 Cal./lb. obtained here for choice white grease is in substantial agreement with the value of 3,980 Cal./lb. for lard reported by Renner and Hill (1958). The corn oil used here probably was quite similar to the samples used by Hill and Renner TABLE 2.—Metabolizable energy values of fats No. of samples Choice white grease Yellow grease Brown grease Poultry grease Bleachable fancy tallow No. 2 tallow All-beef tallow Hydrolyzed animal and vegetable fat Methyl ester of fatty acids Corn oil (refined)
2 2 2 1 2 1 1 2 1 2
Range
Av.
Cal./lb. 3,865-4,028 4,179-4,504 3,480^1,179
Cal./lb. 3,925 4,326 3,830 4,630 3,597 3,451 3,451
3,260-3,772 2,870-3,483 3,993-4,353
3,176 3,457 4,173
(1957), and the values on two different samples are in substantial agreement with the 4070 value reported by the Cornell group. The samples of yellow grease and poultry fat appeared to have energy values higher than the theoretical value. There is no clear explanation for these high values unless these fats influenced the utilization of other feed components which resulted in an apparent higher utilization of energy in the diet. The metabolizable energy values for tallows used here are higher than have been reported by Renner and Hill (1958) or by Potter and Matterson (1960) but are not greatly different from the value reported by Renner and Hill (1960) for tallow measured with chicks at 8 weeks of age. There are several possible explanations for these higher values for tallows. Since most greases and tallows available to the feed industry are blends of various source materials or even mixtures of different fats from a single species, the tallows used here may have more nearly resembled the greases. The titer of one of the choice white greases, for example, was 39.2°C. while one of the bleachable fancy tallows had a titer of 41.0°C, indicating that there was little difference between them. Some of these fats may also have enhanced the utilization of other dietary components, resulting in an apparent high metabolizable energy value for the fat, since Sibbald et al. (1960) reported that the metabolizable energy values for corn showed significant variation when combined with different basal diets. This might indicate that the metabolizable energy value of a single feed ingredient is not an absolute value but may be dependent upon other ration components. It is also possible that different strains or breeds of chicks react differently to the fats. In the last test of this series, three of
363
METABOLIZABLE ENERGY OF FAT TABLE 3.—Metabolizable energy content of fats using two different basal diets
Choice white grease Bleachable fancy tallow Yellow grease
Semipractical diet
Semipurified E-9 diet
Col./lb. 3,865 3,260 4,216
Cal./lb. 3,826 4,026 3,708
the fat samples were tested using both the semi-practical diet and the semi-purified E-9 diet of Hill and Anderson (1958). The results are shown in Table 3. The metabolizable energy values as measured by use of the two diets are not in complete agreement. For the samples of choice white grease, the difference is probably not significant, but for bleachable fancy tallow, the use of the E-9 diet resulted in a considerably higher value and for the yellow grease it resulted in a lower value than was observed using the semi-practical diet. It was also observed that values obtained in duplicate lots fed the E-9 diet were in closer agreement than were values obtained with duplicate lots of chicks fed the semi-practical diet. The absorbability of the fats used in the last two trials of the series was determined. These results are shown in Table 4. It has been observed that extraction of the acetic acid treated droppings sometimes removes a small amount of other lipid-like material, and this error would tend to give a falsely low value for absorbability. With the absorbability values obtained here it was assumed that very little material other than lipid was extracted after hydrolysis. The absorbability values obtained here are somewhat higher than those reported by Fedde et al. (1960) but they are more nearly in agreement with values reported by Biely and March (1957) for tallow and corn oil. The greases and corn oil are also in substantial agreement with values re-
ported by Renner and Hill (1960), while values for the tallows are slightly higher than the 70-82% absorbability reported by Renner and Hill (1960) for chicks up to 8 weeks of age. As a further test of the actual value of the various grades of these fats in commercial feeds, a number of them were fed at the 10% level in a practical type diet for an 8 week period. The diet, shown in Table 1, contained 24.28% protein. Two feeding trials were run, with duplicate lots of 16 chicks in each trial. With the exception of choice white grease and hydrolyzed animal and vegetable fat, different samples of the same type or grade were used in the second trial. The choice white grease, brown grease, all-beef tallow and methyl ester of fatty acids used in this first trial were the same samples used previously for the energy and digestibility studies. Poultry grease and a mixture of pork and beef fat were included in the second trial. The 8 week chick weights, feed conversions, and performance efficiency index (P.E.I.) are shown in Table 5. Performance efficiency index was calculated by multiplying the gain in weight (in grams) for the 8 week period by the reciprocal of feed conversion and TABLE 4.—Absorbability of fats fed to chicks at the 14% level* Trial 3
Trial 4
SemiSemipractical practical diet diet Choice white grease Yellow grease Brown grease Poultry grease Bleachable fancy tallow All-beef tallow Corn oil (refined)
Trial 4 Semipurified diet
%
%
%
95.3 93.6 84.6 94.0
95.8 93.0
99.0 98.5
87.7 78.9 96.8
85.7
97.3
* Computed from dietary fat and total fecal fat, correcting for fecal fat from low-fat reference diet.
364
M.
P.
C U L L E N , O.
G.
R A S M U S S E N A N D O.
H.
M.
WILDER
TABLE 5.—Growth and feed conversion with chicks fed different fats in practical diets Trial 1 8 wk. wt. feed/gain Choice white grease1 Yellow grease Brown grease Poultry grease Bleachable fancy tallow (a) Bleachable fancy tallow (b) Tallow fatty acids (from b) Dark-high-acid tallow Pork and beef tallow All-beef tallow Hydrolyzed animal and vegetable fat Methyl ester of fatty acids No fat added to diet 1
Trial 2 P.E.I. 2
lbs. 3.31 3.25 3.38
1.92 2.03 1.98
7.57 7.14 7.62
3.40** 3.39* 3.28 3.33
1.98 1.93 2.07 2.06
7.62 7.77 7.02 7.20
3.16*** 3.30 3.08***
2.10 1.97 2.21
6.66 7.44 6.11
Choice white grease used as control. ? Gain in wt. (g)
2 P p r f n r m a n r p p f f l n p n r u in flpY z=r 1
8 wk. wt. feed/gain lbs. 3.51 3.54 3.45 3.46 3.54 3.46 3.52 3.21*** 3.44 3.52 3.50 3.24*** 3.27
1.88 1.93 1.96 1.95 1.83 1.88 1.99 2.04 1.91 1.93 1.88 2.01 2.36
P.E.I. 2 8.15 8.00 7.74 7.83 8.54 8.15 7.81 6.86 7.97 8.09 8.23 7.55 6.11
*Mnn 1
\unit gain per unit feed * Significantly better than choice white grease, P < 5 % . ** Significantly better than choice white grease, P < 1 % . *** Significantly less than choice white grease, P < 1 % .
dividing by 100. It is a convenient method of expressing the relative over-all performance of the chicks fed the different diets since a higher value indicates better over-all performance. Pigmentation was observed to be good in all lots with the exception of the group receiving the methyl esters where a depression of pigmentation, as judged by visual observation, was noted in both trials. This is in accord with results reported by Carver (1959). The same samples of choice white grease and hydrolyzed animal and vegetable fat were used in both trials, and it was observed that 8 week chick weights were greater in the second trial than in the first. This would suggest that factors other than the fat were involved. The other fat products represented different samples of the same grade obtained from the same producer at different times. Considerable differences between results obtained from some of the samples were apparent. Bleachable fancy tallow pro-
duced a greater growth than choice white grease in the first trial but not in the second. All-beef tallow produced significantly less growth in the first trial but in the second, with a different sample of fat being used, it gave results approximately equal to choice white grease while feed conversion was practically equal in both trials. The methyl ester of fatty acids allowed significantly less growth in both trials but feed conversion was slightly improved in the second trial over the group receiving no supplementary fat. The variance between similar products was not explained by the difference in analyses of the fats, which are shown in Table 6. The results suggest that the metabolizable energy of any one type of fat when fed to chickens is not an absolute value but may vary depending upon the grade and probably upon the source of the fatty tissues from which the fat was derived. In the grading of commercial fats from animal sources a titer of 40° is accepted as the
365
METABOLIZABLE E N E R G Y o r F A T
TABLE 6.—Analytical data on different animal fats fed Moi ture Trial |& InSoluble . , T Trial ...,. mineral • , Unsapon„ti„ TTotal :c ifiable F.F.A. No. volatile soluble M.I.U. matter matter matter matter
Titer
Choice white grease
1 2
0.13 0.13
0.01 0.01
% 0.01 0.01
% 0.57 0.57
% 0.72 0.72
4.2 4.2
°C. 37.3 37.3
Yellow grease
1 2
0.21 0.63
0.31 2.81
0.02 0.07
0.69 0.46
1.23 3.97
5.9 11.4
40.5 40.8
Brown grease
1 2
0.63 0.32
0.04 0.27
0.12 0.25
1.00 1.57
1.79 2.41
61.3 31.7
39.0 38.7
Poultry grease
2
0.89
0.35
0.49
3.47
5.20
18.0
36.3
Bleachable fancy tallow (a)
1 2
0.09 0.10
0.09 0.13
0.02 0.06
0.42 1.00
0.62 1.29
1.8 5.6
40.9 40.1
Bleachable fancy tallow (b)
1 2
1.29 0.23
0.05 1.10
0.02
0.32 0.46
1.66 1.81
3.5 2.4
40.7 41.0
Tallow fatty acids (froni b )
1 2
0.11 0.05
0.02 0.02
0.01 0.05
0.4S 0.56
0.59 0.68
100.0 99.0
40.8 41.1
Dark high-acid tallow
1 2
0.32 0.72
0.08 0.13
1.12 1.59
2.14 5.68
3.76 8.12
44.2 53.9
42.4 42.3
Pork and beef tallow
2
0.05
0.04
0.01
0.28
0.38
0.6
41.7
All-beef tallow
1 2
0.25 0.04
0.15 0.11
0.02 0.04
0.40 0.48
0.82 0.67
1.3 1.1
44.0 43.9
Hydrolyzed animal and'vegetable fat
1 2
0.67 0.67
0.16 0.16
0.14 0.14
2.22 2.22
3.19 3.19
42.9 42.9
39.6 39.6
Methyl ester of fatty acids
1 2
1.40 0.38
1.84 2.61
0.01 0.12
8.43 4.48
11.68 7.59
13.4
33.5
%
characteristic which delineates a tallow (titer of 40°C. or higher) from a grease (titer of less t h a n 4 0 ° C ) . Since fat from beef animals normally has a titer in excess of 40°, it is commonly accepted t h a t fat from beef animals will be graded as a tallow. However, it has been shown by Dugan et al. (1952) t h a t certain tissues from beef animals may yield a fat having a titer considerably less t h a n 40°. I t is therefore probable t h a t some of the tallows found on the market may contain a higher percentage of unsaturated fatty acids t h a n do other tallows and will perform much like the greases when fed to chicks. The results also suggest t h a t any
%
%
of the common grades of animal fat, or hydrolyzed animal and vegetable fat, t h a t are normally found on the market should give good results, b u t t h a t other factors are also involved. Differences in the birds or other feed ingredients may play a part. F a t t y materials such as the tallow fatty acids and the dark-high-acid tallow were special products and as such, would normally not be used in feeds. SUMMARY Metabolizable energy, absorbability and effect on growth and feed conversion have been measured on a number of fat samples including different grades of tal-
366
M . P . C U L L E N , 0 . G. R A S M U S S E N AND 0 . H . M .
lows and greases, hydrolyzed animal and vegetable fat and methyl ester of fatty acids when fed to chicks. Energy and absorbability values were measured when the fats were incorporated into a semipractical diet, and three samples were also tested in a semi-purified diet. Average values for metabolizable energy in Calories per pound, were: choice white grease, 3,925; yellow grease, 4,326; brown grease, 3,830; poultry grease, 4,630; bleachable fancy tallow, 3,597; N o . 2 tallow, 3,451; all-beef tallow, 3,451; hydrolyzed animal and vegetable fat, 3,176; and methyl ester of fatty acids, 3,457. The reason for the higher t h a n theoretical values for yellow grease and poultry fat is not readily apparent. A sample of choice white grease appeared to have practically the same energy value when measured using a semi-practical or a semi-purified diet b u t values for bleachable fancy tallow and yellow grease varied considerably when used with the two diets. Apparent absorbabilities of the fats tested were: choice white grease, 9 5 % ; yellow grease, 9 3 % ; brown grease, 8 4 % ; poultry grease, 9 4 % ; bleachable fancy tallow, 85 and 8 7 % ; all-beef tallow, 7 9 % ; and refined corn oil, 9 7 % . In the practical feeding tests, all groups of chicks in a second test performed better t h a n those in the first test except those fed a dark-high-acid tallow, and all except those chicks fed this dark-high-acid tallow were heavier at 8 weeks t h a n control groups having no added fat in their diet. Feed conversion was improved by all fats used in the test. I t is concluded t h a t any of the grades of animal fat or hydrolyzed animal and vegetable fat t h a t are commonly found on the market will give satisfactory results. Such materials as tallow fatty acids and dark-high-acid tallow were special prod-
WILDER
ucts which did not perform as well as the other grades of fats. REFERENCES Anderson, D. L., 1955. The energy value of poultry feeds. Proc. 1955 Cornell Nutr. Conf. for Feed Mnfgrs., Nov. 3-4, p. 5-10. Association of Official Agricultural Chemists, 1950. Official Methods of Analysis, 7th ed. Washington, 4, D. C. Biely, J., and B. March, 1957. Fat studies in poultry. 7. Fat and nitrogen retention in chicks fed diets containing different levels of fat and protein. Poultry Sci. 36:1235-1240. Carver, D. S., 1959. Variation in the effects of fat supplements on broiler pigmentation, growth and feed conversion. Poultry Sci. 38: 71-76. Dugan, L. R., J. E. Maroney and M. Petheram, 1952. Study of carcass fats of beef animals. 1. The composition of beef brisket fat. J. Am. Oil Chemists Soc. 29: 298-300. Fedde, M. R., P. E. Waibel and R. E. Burger, 1960. Factors affecting the absorbability of certain dietary fats in the chick. J. Nutrition, 70: 447452. Hill, F. W., and D. L. Anderson, 1958. Comparison of metabolizable energy and productive energy determination with growing chicks. J. Nutrition, 64: 587-604. Hill, F. W., L. B. Carew, Jr. and R. Renner, 1956. Studies of the efficiency of energy utilization by the growing chick. Proc. 1956 Cornell Nutr. Conf. for Feed Mnfgrs. Nov. 8-9. p. 31-36. Hill, F. W., and R. Renner, 1957. Metabolizable energy values of feedstuffs for poultry and their use in formulation of rations. Proc. 1957, Cornell Nutr. Conf. for Feed Mnfgrs., Oct. 30-Nov. 1 p. 22-32. Hopkins, C. Y., T. K. Murray and J. A. Campbell, 1955. Optimum ratio of saturated to mono-unsaturated fatty acids in rat diets. Can. J. Biochem. Physiol. 33: 1047-1054. Potter, L. M., L. D. Matterson, A. W. Arnold, W. J. Pudelkiewicz and E. P. Singsen, 1958. Studies evaluating energy content of feeds for the chick. 1. The evaluation of alpha cellulose for its metabolizable energy and productive energy. Poultry Sci. 37: 1234. Potter, L. M., and L. D. Matterson, 1960. Metabolizable energy of feed ingredients for the growing chick. Poultry Sci. 39: 781-782. Renner, R., and F. W. Hill, 1958. Metabolizable energy values of fats and fatty acids for chickens. Proc. of 1958 Cornell Nutr. Conf. for Feed
METABOLIZABLE ENERGY OF FAT Mnfgrs., Nov. 12-14. p. 95-100. Renner, R., and F. W. Hill, 1960. The utilization of corn oil, lard and tallow by chickens of various ages. Poultry Sci. 39: 849-854. Sibbald, I. R., J. D. Summers and S. J. Slinger, 1960. Factors affecting the metabolizable energy content of poultry feeds. Poultry Sci. 39: 544-556. Siedler, A. J., H. E. Scheid and B. S. Schweigert,
367
1955. Effects of different grades of animal fats on the performance of chicks. Poultry Sci. 34: 411-414. Sunde, M. L., 1956. Effects of fats and fatty acids in chick rations. Poultry Sci. 35: 362-368. Waibel, P. E., 1955. Effect of dietary protein level and added tallow on growth and carcass composition of chicks. Poultry Sci. 34: 1226.
Evidence for Chick Growth Inhibitors in Several Legume Seeds1 E L D O N W. K I E N H O L Z , 2 L E O S. J E N S E N AND J A M E S M C G I N N I S
Department of Poultry Science, Washington State University, Pullman (Received for publication October 17, 1960)
T
H E presence of growth inhibitors in m a n y legume seeds is well established. Recent studies at this laboratory showed t h a t autoclaving peas improved their nutritional value for chicks and poults (Kienholz et al., 1959), showing t h a t peas also contain a growth inhibitor. One purpose of the present study was to survey the chick growth inhibiting properties of several legume seeds not usually included in animal rations. Other means were also sought to overcome the growth depressing effect of raw peas. Several investigators have shown t h a t chicks require a high level of zinc with certain diets. O'Dell and Savage (1957) and Supplee et al. (1958) observed t h a t adding zinc to a diet containing isolated soybean protein improved chick growth. Adding zinc to a diet containing soybean oil meal, however, did not improve chick growth. Norris and Ziegler (1958) determined the zinc requirement of chicks fed purified diets to be 15 or 33 1
Scientific Paper No. 2010, Washington Agricultural Experiment Stations, Pullman. Project No. 1533. 2 Present Address: Department of Poultry Science, University of Wisconsin, Madison.
ppm., depending upon the type of protein used. Pino and McGinnis (1959) found zinc added to a chick diet containing uncooked field beans gave increased growth. Experiments were conducted to determine if the improved nutritional value of cooked peas was related to need for or availability of zinc. PROCEDURE New Hampshire chicks were used in all experiments. Three groups of ten dayold chicks were fed each diet in experiments 1, 3 and 4. Experiment 2 was planned to observe the effect of feeding the same diets used in experiment 1 (unused feed) to older chicks. Three-week-old chicks (four males and four females) were selectively placed in each pen so t h a t all eight groups averaged about 190 grams. Experiment 2 was conducted for one week, experiments 1 and 3 for three weeks, and experiment 4 for two weeks. Birds were kept in a continuously lighted, air-conditioned room and housed in electrically heated batteries with raised wire floors. The feed and water containers, as well as batteries, were galvanized. Composition of experimental a n d con-
I
T HAS been shown by Sunde (1956) and others that the presence of fat in the diet of the chicken has a beneficial effect upon the efficiency of feed utilization. Waibel (1955) and others have shown that the presence of fat in the diet frequently has a beneficial influence on growth rate also. These effects of added fat in poultry feeds have led to the development of more highly efficient feeds and emphasized the need for more precise information regarding the energy content of fats and the utilization of various types and grades of fats when fed. The energy content of poultry feed ingredients has been studied by Hill and Anderson (1958) and Potter et al. (1958), and it was shown that metabolizable energy is a more valid measure of energy content of poultry feeds than is productive energy. Metabolizable energy values ranging from 2,860 to 3,300 Calories per pound have been reported for tallow by Anderson (1955), Hill et al. (1956), Hill and Renner (1957), and Renner and Hill (1958). Potter and Matterson (1960) reported a value of 3,190 Calories per pound for tallow. The metabolizable energy value for lard was reported by Renner and Hill (1958) to be 3,980 Calories per pound and the percentage utilization of the lard was 93.4 while tallow had an energy value of 2,860 Calories per pound and utilization was only 67.0 percent. Fedde et al. (1960) studied the absorbability of fats in the chick and reported that hog grease used at Journal Paper No. 217, American Meat Institute Foundation.
a 20% level in the ration had an apparent absorption coefficient of 85.4 in chicks at 1 to 2 weeks of age and 93.0 at 7 to 8 weeks of age. In the same study, tallow absorption coefficients increased from 53 at 1 week of age to 80 at 12 weeks of age. Siedler et al. (1955) studied the effects of the addition of 3 or 6% stabilized animal fats or 3 % free fatty acids to a high energy broiler ration. The materials used were choice white grease, yellow grease, brown grease, prime tallow, No. 2 tallow and fatty acids prepared from choice white grease. These workers reported excellent utilization of choice white grease, yellow grease, brown grease or fatty acids at the 3 % level, with some reduction in calcoric efficiency when these fats were fed at the 6% level. The tallows were well utilized in the second experiment. The chicks used in the two experiments were obtained from different hatcheries and those chicks used in the second experiment grew at a more rapid rate than those in the first experiment which might suggest that the rapid growing birds are able to utilize tallow more efficiently than the slower growing birds. Renner and Hill (1960) later studied the utilization of corn oil, lard and tallow by chickens of various ages and reported that metabolizable energy and absorbability were comparable for chicks fed lard and tallow, and that age of the chick affected the utilization of tallow since absorbability of tallow ranged from 70% for chicks at 2 weeks of age to 82% for chicks at 8 weeks of age.
360
METABOLIZABLE ENERGY OF FAT
The purpose of the present study was to measure the metabolizable energy content and apparent absorbability of a number of different types and grades of fats, and the general performance of these types and grades of fats when fed to chicks in semi-practical rations. MATERIALS AND METHODS
The method used for measuring metabolizable energy was patterned after that used by Hill and Anderson (1958) except that the basal diet was formulated insofar as possible from ingredients commonly found in commercial poultry rations. Glucose (Cerelose) was used at a 14% level in the basal ration as a reference standard and was completely replaced by the test fats in experimental diets. The basal diet is shown in Table 1. Four experiments were run in measuring metabolizable energy; in some cases the measurements were repeated on the same samples and in others different samples were used. In the fourth experiment, both the semipractical and the E-9 diet of Hill and Anderson (1958) were used.
361
TABLE 1.—Composition of diets Semipractical
%
Ground yellow corn 36.73 Soybean oil meal (44% protein) 28.62 Glucose (Cerelose) 14.00 M e a t and bone meal (50% protein) 8.00 Dried brewers' yeast 4.00 Corn gluten meal 5.00 Dehydrated alfalfa meal 1.00 DL~Methionine 0.05 Pulverized limestone 0.50 Di-calcium phosphate 0.50 Iodized salt 0.50 Vitamin A & D oil (2,200 U.S.P. units A a n d 4001.C. units D / g . ) 0.25 Choline chloride (25%) 0.50 Chlortetracycline supplement (1.8 0.25 g./lb.). Trace mineral mix 0.10' Vitamin mix Test fat Ground wheat Casein (crude) Gelatin Hydrogenated vegetable fat Fish meal (menhaden) Fish solubles (dry basis) Dried whey
*
E-92
% 17.5 44.1 2.5
2.0 1.0 0.5
Practical diet
%
40.00 31.40 8.00 2.00 5.00 1.00 0.05 0.50 0.50 0.50 0.50
0.42 0.502
*
0.25 0.101 0.203 10.00
9.0 10.5 2.5 2.5 4.0 1.0 2.0
1 Supplied the following in mg. per kilogram of diet: FeS04 7H*0, 200; CuSO<-HiO 12.5; C0SO4, 2.5; ZnSOj-HzO, 10.00; and MnS0 4 , 62.5. 2 Hill and Anderson (1958). 3 Supplied per kilogram of diet: 6.6 mg. riboflavin, 13.2 mg. calcium pantothenate, 2.2 mg. menadione, 3.52 mg. pyridoxine HCI, 0.77 mg. folic acid, 0.01 mg. vit. B12, 5,000 U.S.P. units Vit. A, and 560 I.C. units Da. * Substituted for Cerelose in test diets.
used in determining intake-excretion ratios, Nitrogen was determined by the Kjeldahl method (A.O.A.C, 7th Ed;, 23.8, Day-old cockerels were obtained for 2.24 and 2.22), combustible energy by use in all experiments. In the first study Parr oxygen bomb calorimeter, chromic the chicks were Hyline cockerels and in oxide by the method described by Hill and subsequent tests, VantressX Arbor Acre Anderson (1958), dietary fat by extracWhite Rocks were used. The chicks were tion with petroleum ether, and total lipid kept in battery brooders on raised wire in excreta by extraction with petroleum floors and feed and water were supplied ether followed by acetic acid hydrolysis ad libitum. All of the chicks received the and reextraction as described by Hopkins basal diet for two weeks after which they etal. (1955). were distributed according to weight into A total of 16 different samples of fats duplicate lots of 12 chicks each. Weight were obtained from 9 different producers gain and feed consumption records.were for the metabolizable energy studies. Rekept to provide an index of the general fined corn oil was included in two of the condition of the chicks. The chicks were tests, using a new sample of a different fed their respective experimental diets for brand for the second trial. The refined two weeks, and collections of excreta were corn oil was included with the expectation made during the last week when the that it would be a relatively standardized chicks were between 3 and 4 weeks of age. reference fat. The chromic oxide indicator method was Apparent absorbability of the fats was
362
M. P. CULLEN, O. G. RASMUSSEN AND O. H. M. WILDER
studied in the third and fourth trials to provide additional information regarding utilization of the fats. Fats used in the metabolizable energy studies included choice white grease, yellow grease, brown grease, poultry fat, bleachable fancy tallow, No. 2 tallow, all-beef tallow, hydrolyzed animal and vegetable fat, fatty acid methyl ester and refined corn oil. Two additional tests were run in which chicks were fed the test fats at a level of 10% in a practical ration for an 8-week period. Duplicate lots of 16 chicks each were used in these tests. Chick weights and feed consumption records were recorded. The ration used in this test is shown in Table 1. RESULTS AND DISCUSSION
The metabolizable energy (M.E.) values are shown in Table 2. Many of the fats offered to the feed trade are mixtures having varying glyceride structures and samples of any one grade may vary from time to time which may account for some of the variation observed in the different samples tested. Choice white grease is an unrefined fat with a fatty acid composition similar to lard. The average M.E. value of 3,925 Cal./lb. obtained here for choice white grease is in substantial agreement with the value of 3,980 Cal./lb. for lard reported by Renner and Hill (1958). The corn oil used here probably was quite similar to the samples used by Hill and Renner TABLE 2.—Metabolizable energy values of fats No. of samples Choice white grease Yellow grease Brown grease Poultry grease Bleachable fancy tallow No. 2 tallow All-beef tallow Hydrolyzed animal and vegetable fat Methyl ester of fatty acids Corn oil (refined)
2 2 2 1 2 1 1 2 1 2
Range
Av.
Cal./lb. 3,865-4,028 4,179-4,504 3,480^1,179
Cal./lb. 3,925 4,326 3,830 4,630 3,597 3,451 3,451
3,260-3,772 2,870-3,483 3,993-4,353
3,176 3,457 4,173
(1957), and the values on two different samples are in substantial agreement with the 4070 value reported by the Cornell group. The samples of yellow grease and poultry fat appeared to have energy values higher than the theoretical value. There is no clear explanation for these high values unless these fats influenced the utilization of other feed components which resulted in an apparent higher utilization of energy in the diet. The metabolizable energy values for tallows used here are higher than have been reported by Renner and Hill (1958) or by Potter and Matterson (1960) but are not greatly different from the value reported by Renner and Hill (1960) for tallow measured with chicks at 8 weeks of age. There are several possible explanations for these higher values for tallows. Since most greases and tallows available to the feed industry are blends of various source materials or even mixtures of different fats from a single species, the tallows used here may have more nearly resembled the greases. The titer of one of the choice white greases, for example, was 39.2°C. while one of the bleachable fancy tallows had a titer of 41.0°C, indicating that there was little difference between them. Some of these fats may also have enhanced the utilization of other dietary components, resulting in an apparent high metabolizable energy value for the fat, since Sibbald et al. (1960) reported that the metabolizable energy values for corn showed significant variation when combined with different basal diets. This might indicate that the metabolizable energy value of a single feed ingredient is not an absolute value but may be dependent upon other ration components. It is also possible that different strains or breeds of chicks react differently to the fats. In the last test of this series, three of
363
METABOLIZABLE ENERGY OF FAT TABLE 3.—Metabolizable energy content of fats using two different basal diets
Choice white grease Bleachable fancy tallow Yellow grease
Semipractical diet
Semipurified E-9 diet
Col./lb. 3,865 3,260 4,216
Cal./lb. 3,826 4,026 3,708
the fat samples were tested using both the semi-practical diet and the semi-purified E-9 diet of Hill and Anderson (1958). The results are shown in Table 3. The metabolizable energy values as measured by use of the two diets are not in complete agreement. For the samples of choice white grease, the difference is probably not significant, but for bleachable fancy tallow, the use of the E-9 diet resulted in a considerably higher value and for the yellow grease it resulted in a lower value than was observed using the semi-practical diet. It was also observed that values obtained in duplicate lots fed the E-9 diet were in closer agreement than were values obtained with duplicate lots of chicks fed the semi-practical diet. The absorbability of the fats used in the last two trials of the series was determined. These results are shown in Table 4. It has been observed that extraction of the acetic acid treated droppings sometimes removes a small amount of other lipid-like material, and this error would tend to give a falsely low value for absorbability. With the absorbability values obtained here it was assumed that very little material other than lipid was extracted after hydrolysis. The absorbability values obtained here are somewhat higher than those reported by Fedde et al. (1960) but they are more nearly in agreement with values reported by Biely and March (1957) for tallow and corn oil. The greases and corn oil are also in substantial agreement with values re-
ported by Renner and Hill (1960), while values for the tallows are slightly higher than the 70-82% absorbability reported by Renner and Hill (1960) for chicks up to 8 weeks of age. As a further test of the actual value of the various grades of these fats in commercial feeds, a number of them were fed at the 10% level in a practical type diet for an 8 week period. The diet, shown in Table 1, contained 24.28% protein. Two feeding trials were run, with duplicate lots of 16 chicks in each trial. With the exception of choice white grease and hydrolyzed animal and vegetable fat, different samples of the same type or grade were used in the second trial. The choice white grease, brown grease, all-beef tallow and methyl ester of fatty acids used in this first trial were the same samples used previously for the energy and digestibility studies. Poultry grease and a mixture of pork and beef fat were included in the second trial. The 8 week chick weights, feed conversions, and performance efficiency index (P.E.I.) are shown in Table 5. Performance efficiency index was calculated by multiplying the gain in weight (in grams) for the 8 week period by the reciprocal of feed conversion and TABLE 4.—Absorbability of fats fed to chicks at the 14% level* Trial 3
Trial 4
SemiSemipractical practical diet diet Choice white grease Yellow grease Brown grease Poultry grease Bleachable fancy tallow All-beef tallow Corn oil (refined)
Trial 4 Semipurified diet
%
%
%
95.3 93.6 84.6 94.0
95.8 93.0
99.0 98.5
87.7 78.9 96.8
85.7
97.3
* Computed from dietary fat and total fecal fat, correcting for fecal fat from low-fat reference diet.
364
M.
P.
C U L L E N , O.
G.
R A S M U S S E N A N D O.
H.
M.
WILDER
TABLE 5.—Growth and feed conversion with chicks fed different fats in practical diets Trial 1 8 wk. wt. feed/gain Choice white grease1 Yellow grease Brown grease Poultry grease Bleachable fancy tallow (a) Bleachable fancy tallow (b) Tallow fatty acids (from b) Dark-high-acid tallow Pork and beef tallow All-beef tallow Hydrolyzed animal and vegetable fat Methyl ester of fatty acids No fat added to diet 1
Trial 2 P.E.I. 2
lbs. 3.31 3.25 3.38
1.92 2.03 1.98
7.57 7.14 7.62
3.40** 3.39* 3.28 3.33
1.98 1.93 2.07 2.06
7.62 7.77 7.02 7.20
3.16*** 3.30 3.08***
2.10 1.97 2.21
6.66 7.44 6.11
Choice white grease used as control. ? Gain in wt. (g)
2 P p r f n r m a n r p p f f l n p n r u in flpY z=r 1
8 wk. wt. feed/gain lbs. 3.51 3.54 3.45 3.46 3.54 3.46 3.52 3.21*** 3.44 3.52 3.50 3.24*** 3.27
1.88 1.93 1.96 1.95 1.83 1.88 1.99 2.04 1.91 1.93 1.88 2.01 2.36
P.E.I. 2 8.15 8.00 7.74 7.83 8.54 8.15 7.81 6.86 7.97 8.09 8.23 7.55 6.11
*Mnn 1
\unit gain per unit feed * Significantly better than choice white grease, P < 5 % . ** Significantly better than choice white grease, P < 1 % . *** Significantly less than choice white grease, P < 1 % .
dividing by 100. It is a convenient method of expressing the relative over-all performance of the chicks fed the different diets since a higher value indicates better over-all performance. Pigmentation was observed to be good in all lots with the exception of the group receiving the methyl esters where a depression of pigmentation, as judged by visual observation, was noted in both trials. This is in accord with results reported by Carver (1959). The same samples of choice white grease and hydrolyzed animal and vegetable fat were used in both trials, and it was observed that 8 week chick weights were greater in the second trial than in the first. This would suggest that factors other than the fat were involved. The other fat products represented different samples of the same grade obtained from the same producer at different times. Considerable differences between results obtained from some of the samples were apparent. Bleachable fancy tallow pro-
duced a greater growth than choice white grease in the first trial but not in the second. All-beef tallow produced significantly less growth in the first trial but in the second, with a different sample of fat being used, it gave results approximately equal to choice white grease while feed conversion was practically equal in both trials. The methyl ester of fatty acids allowed significantly less growth in both trials but feed conversion was slightly improved in the second trial over the group receiving no supplementary fat. The variance between similar products was not explained by the difference in analyses of the fats, which are shown in Table 6. The results suggest that the metabolizable energy of any one type of fat when fed to chickens is not an absolute value but may vary depending upon the grade and probably upon the source of the fatty tissues from which the fat was derived. In the grading of commercial fats from animal sources a titer of 40° is accepted as the
365
METABOLIZABLE E N E R G Y o r F A T
TABLE 6.—Analytical data on different animal fats fed Moi ture Trial |& InSoluble . , T Trial ...,. mineral • , Unsapon„ti„ TTotal :c ifiable F.F.A. No. volatile soluble M.I.U. matter matter matter matter
Titer
Choice white grease
1 2
0.13 0.13
0.01 0.01
% 0.01 0.01
% 0.57 0.57
% 0.72 0.72
4.2 4.2
°C. 37.3 37.3
Yellow grease
1 2
0.21 0.63
0.31 2.81
0.02 0.07
0.69 0.46
1.23 3.97
5.9 11.4
40.5 40.8
Brown grease
1 2
0.63 0.32
0.04 0.27
0.12 0.25
1.00 1.57
1.79 2.41
61.3 31.7
39.0 38.7
Poultry grease
2
0.89
0.35
0.49
3.47
5.20
18.0
36.3
Bleachable fancy tallow (a)
1 2
0.09 0.10
0.09 0.13
0.02 0.06
0.42 1.00
0.62 1.29
1.8 5.6
40.9 40.1
Bleachable fancy tallow (b)
1 2
1.29 0.23
0.05 1.10
0.02
0.32 0.46
1.66 1.81
3.5 2.4
40.7 41.0
Tallow fatty acids (froni b )
1 2
0.11 0.05
0.02 0.02
0.01 0.05
0.4S 0.56
0.59 0.68
100.0 99.0
40.8 41.1
Dark high-acid tallow
1 2
0.32 0.72
0.08 0.13
1.12 1.59
2.14 5.68
3.76 8.12
44.2 53.9
42.4 42.3
Pork and beef tallow
2
0.05
0.04
0.01
0.28
0.38
0.6
41.7
All-beef tallow
1 2
0.25 0.04
0.15 0.11
0.02 0.04
0.40 0.48
0.82 0.67
1.3 1.1
44.0 43.9
Hydrolyzed animal and'vegetable fat
1 2
0.67 0.67
0.16 0.16
0.14 0.14
2.22 2.22
3.19 3.19
42.9 42.9
39.6 39.6
Methyl ester of fatty acids
1 2
1.40 0.38
1.84 2.61
0.01 0.12
8.43 4.48
11.68 7.59
13.4
33.5
%
characteristic which delineates a tallow (titer of 40°C. or higher) from a grease (titer of less t h a n 4 0 ° C ) . Since fat from beef animals normally has a titer in excess of 40°, it is commonly accepted t h a t fat from beef animals will be graded as a tallow. However, it has been shown by Dugan et al. (1952) t h a t certain tissues from beef animals may yield a fat having a titer considerably less t h a n 40°. I t is therefore probable t h a t some of the tallows found on the market may contain a higher percentage of unsaturated fatty acids t h a n do other tallows and will perform much like the greases when fed to chicks. The results also suggest t h a t any
%
%
of the common grades of animal fat, or hydrolyzed animal and vegetable fat, t h a t are normally found on the market should give good results, b u t t h a t other factors are also involved. Differences in the birds or other feed ingredients may play a part. F a t t y materials such as the tallow fatty acids and the dark-high-acid tallow were special products and as such, would normally not be used in feeds. SUMMARY Metabolizable energy, absorbability and effect on growth and feed conversion have been measured on a number of fat samples including different grades of tal-
366
M . P . C U L L E N , 0 . G. R A S M U S S E N AND 0 . H . M .
lows and greases, hydrolyzed animal and vegetable fat and methyl ester of fatty acids when fed to chicks. Energy and absorbability values were measured when the fats were incorporated into a semipractical diet, and three samples were also tested in a semi-purified diet. Average values for metabolizable energy in Calories per pound, were: choice white grease, 3,925; yellow grease, 4,326; brown grease, 3,830; poultry grease, 4,630; bleachable fancy tallow, 3,597; N o . 2 tallow, 3,451; all-beef tallow, 3,451; hydrolyzed animal and vegetable fat, 3,176; and methyl ester of fatty acids, 3,457. The reason for the higher t h a n theoretical values for yellow grease and poultry fat is not readily apparent. A sample of choice white grease appeared to have practically the same energy value when measured using a semi-practical or a semi-purified diet b u t values for bleachable fancy tallow and yellow grease varied considerably when used with the two diets. Apparent absorbabilities of the fats tested were: choice white grease, 9 5 % ; yellow grease, 9 3 % ; brown grease, 8 4 % ; poultry grease, 9 4 % ; bleachable fancy tallow, 85 and 8 7 % ; all-beef tallow, 7 9 % ; and refined corn oil, 9 7 % . In the practical feeding tests, all groups of chicks in a second test performed better t h a n those in the first test except those fed a dark-high-acid tallow, and all except those chicks fed this dark-high-acid tallow were heavier at 8 weeks t h a n control groups having no added fat in their diet. Feed conversion was improved by all fats used in the test. I t is concluded t h a t any of the grades of animal fat or hydrolyzed animal and vegetable fat t h a t are commonly found on the market will give satisfactory results. Such materials as tallow fatty acids and dark-high-acid tallow were special prod-
WILDER
ucts which did not perform as well as the other grades of fats. REFERENCES Anderson, D. L., 1955. The energy value of poultry feeds. Proc. 1955 Cornell Nutr. Conf. for Feed Mnfgrs., Nov. 3-4, p. 5-10. Association of Official Agricultural Chemists, 1950. Official Methods of Analysis, 7th ed. Washington, 4, D. C. Biely, J., and B. March, 1957. Fat studies in poultry. 7. Fat and nitrogen retention in chicks fed diets containing different levels of fat and protein. Poultry Sci. 36:1235-1240. Carver, D. S., 1959. Variation in the effects of fat supplements on broiler pigmentation, growth and feed conversion. Poultry Sci. 38: 71-76. Dugan, L. R., J. E. Maroney and M. Petheram, 1952. Study of carcass fats of beef animals. 1. The composition of beef brisket fat. J. Am. Oil Chemists Soc. 29: 298-300. Fedde, M. R., P. E. Waibel and R. E. Burger, 1960. Factors affecting the absorbability of certain dietary fats in the chick. J. Nutrition, 70: 447452. Hill, F. W., and D. L. Anderson, 1958. Comparison of metabolizable energy and productive energy determination with growing chicks. J. Nutrition, 64: 587-604. Hill, F. W., L. B. Carew, Jr. and R. Renner, 1956. Studies of the efficiency of energy utilization by the growing chick. Proc. 1956 Cornell Nutr. Conf. for Feed Mnfgrs. Nov. 8-9. p. 31-36. Hill, F. W., and R. Renner, 1957. Metabolizable energy values of feedstuffs for poultry and their use in formulation of rations. Proc. 1957, Cornell Nutr. Conf. for Feed Mnfgrs., Oct. 30-Nov. 1 p. 22-32. Hopkins, C. Y., T. K. Murray and J. A. Campbell, 1955. Optimum ratio of saturated to mono-unsaturated fatty acids in rat diets. Can. J. Biochem. Physiol. 33: 1047-1054. Potter, L. M., L. D. Matterson, A. W. Arnold, W. J. Pudelkiewicz and E. P. Singsen, 1958. Studies evaluating energy content of feeds for the chick. 1. The evaluation of alpha cellulose for its metabolizable energy and productive energy. Poultry Sci. 37: 1234. Potter, L. M., and L. D. Matterson, 1960. Metabolizable energy of feed ingredients for the growing chick. Poultry Sci. 39: 781-782. Renner, R., and F. W. Hill, 1958. Metabolizable energy values of fats and fatty acids for chickens. Proc. of 1958 Cornell Nutr. Conf. for Feed
METABOLIZABLE ENERGY OF FAT Mnfgrs., Nov. 12-14. p. 95-100. Renner, R., and F. W. Hill, 1960. The utilization of corn oil, lard and tallow by chickens of various ages. Poultry Sci. 39: 849-854. Sibbald, I. R., J. D. Summers and S. J. Slinger, 1960. Factors affecting the metabolizable energy content of poultry feeds. Poultry Sci. 39: 544-556. Siedler, A. J., H. E. Scheid and B. S. Schweigert,
367
1955. Effects of different grades of animal fats on the performance of chicks. Poultry Sci. 34: 411-414. Sunde, M. L., 1956. Effects of fats and fatty acids in chick rations. Poultry Sci. 35: 362-368. Waibel, P. E., 1955. Effect of dietary protein level and added tallow on growth and carcass composition of chicks. Poultry Sci. 34: 1226.
Evidence for Chick Growth Inhibitors in Several Legume Seeds1 E L D O N W. K I E N H O L Z , 2 L E O S. J E N S E N AND J A M E S M C G I N N I S
Department of Poultry Science, Washington State University, Pullman (Received for publication October 17, 1960)
T
H E presence of growth inhibitors in m a n y legume seeds is well established. Recent studies at this laboratory showed t h a t autoclaving peas improved their nutritional value for chicks and poults (Kienholz et al., 1959), showing t h a t peas also contain a growth inhibitor. One purpose of the present study was to survey the chick growth inhibiting properties of several legume seeds not usually included in animal rations. Other means were also sought to overcome the growth depressing effect of raw peas. Several investigators have shown t h a t chicks require a high level of zinc with certain diets. O'Dell and Savage (1957) and Supplee et al. (1958) observed t h a t adding zinc to a diet containing isolated soybean protein improved chick growth. Adding zinc to a diet containing soybean oil meal, however, did not improve chick growth. Norris and Ziegler (1958) determined the zinc requirement of chicks fed purified diets to be 15 or 33 1
Scientific Paper No. 2010, Washington Agricultural Experiment Stations, Pullman. Project No. 1533. 2 Present Address: Department of Poultry Science, University of Wisconsin, Madison.
ppm., depending upon the type of protein used. Pino and McGinnis (1959) found zinc added to a chick diet containing uncooked field beans gave increased growth. Experiments were conducted to determine if the improved nutritional value of cooked peas was related to need for or availability of zinc. PROCEDURE New Hampshire chicks were used in all experiments. Three groups of ten dayold chicks were fed each diet in experiments 1, 3 and 4. Experiment 2 was planned to observe the effect of feeding the same diets used in experiment 1 (unused feed) to older chicks. Three-week-old chicks (four males and four females) were selectively placed in each pen so t h a t all eight groups averaged about 190 grams. Experiment 2 was conducted for one week, experiments 1 and 3 for three weeks, and experiment 4 for two weeks. Birds were kept in a continuously lighted, air-conditioned room and housed in electrically heated batteries with raised wire floors. The feed and water containers, as well as batteries, were galvanized. Composition of experimental a n d con-