IN RECENT years, fats have become a

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1 Influence of Fats in Rations on Storage Quality of Poultry M. I. DARROW AND E. 0. ESSARY Swift & Company, Research Laboratories, Chicago, III. (Received for publication August, 195) IN RECENT years, fats have become a surplus commodity. Research, directed toward finding new uses for fats, has shown that fat is a desirable ingredient in livestock and poultry rations and as a result, increasing amounts of fats are being used in feeds. Through the use of high energy fats, lower cost rations which give satisfactory growth response and which have better physical characteristics have been developed. It was reported by Scott el al. (197) that high energy poultry feeds outperform low energy rations. Siedler and Schweigert (1953) observed that the growth response in New Hampshire chicks on 2, or 8 percent fat (choice white grease) with or without supplements of choline or choline plus antibiotics and vitamin B i2 did not increase rate of gain over that of chicks on the basal ration for a period of 9 weeks. An increase in rate of gain was noted, however, in White Rock male chicks on these same rations. Rice et al. (195) reported that growth rate and efficiency of feed utilization of chicks were improved by including various fats in the ration. Sunde (195) found that the addition of fats in poultry rations improved the efficiency of feed utilization. In addition to the work cited showing that fats improved growth and feed efficiency, it has been reported that the feeding of fats and/or oils has an effect on the stability of the deposited fat, Admundsen et al. (1938), Kummerow et al. (197). Kummerow, Hite and Kloxin (198) and 27 Chu and Kummerow (1950) observed that linolenic acid was deposited in the skin, gizzard, and liver of turkeys which had received supplements of linseed oil. The resistance of poultry fat to rancidification was dependent on the amount of linolenic acid deposited in the skin tissue and the amount and nature of natural antioxidants. Barnes, Lundberg, Hanson and Burr (193) reported that alpha tocopherol helped to stabilize animal fats against oxidation. Kummerow et al. (197) found that the degree of stability of deposited fat could be modified by the addition of certain supplements such as extracts of alfalfa leaf meal, carotene, cholesterol, ethanolamine, or choline. Work by Kummerow, Vail, Conrad and Avery (198) showed that a correlation probably existed between the organoleptic characteristics of the carcass and the peroxide and aldehyde values of the extracted skin fat. When the peroxide and aldehyde values were less than 10 and 25 respectively, the cooked carcass was acceptable to the taste panel. Unless the storage life and flavor of birds fed various fats are satisfactory, the the value of fats in feeds becomes a matter of experimentation only. Published data on the use of fats have been directed mostly to its influence on growth rate, efficiency of feed utilization and methods of stabilizing the deposited fat; therefore, it seemed advisable to further study the influence of dietary fats on the organoleptic and chemical characteristics of deposited fat in storage poultry.

2 28 M. I. DARROW AND E. 0. ESSARY EXPERIMENTAL PROCEDURE Day old broiler type New Hampshire chicks were randomly distributed into four lots of 20 birds each. All birds were raised in battery brooders located in a temperature controlled building. A commercial type broiler ration was used as the control. The same formula was modified for the experimental groups by replacing corn with an equal weight of the fat to be studied. Fats used in these experiments were tallow at the 5 percent level and hydrolyzed cottonseed fats (foots*) and soybean fats at 5 and 10 percent levels. At the 10 percent level, the protein, vitamins, and minerals were adjusted to maintain the caloric-nutrient ratios equal to those of the control ration. Feed and water were supplied ad libitum. Two experiments each containing four lots, were conducted. At 10 weeks of age, four males and four females from each lot were selected at random and processed. The birds were sacrificed by cutting the jugular vein, scalding with 128 F. water, eviscerating while warm, and chilling in ice slush. Immediately after chilling, the birds were packaged and frozen at temperatures of 0 F. to 5 F. In Test 1, half of the birds in each lot were wrapped in wax paper and the other half were packaged in vacuum-type moisture-proof film. Only the latter was used in Test 2. In both tests, after 6 and 9 months storage, two birds of each sex from each lot were defrosted in a 50 F. cooler. Half of each bird was cooked by broiling in order to obtain organoleptic values for aroma, flavor, and juiciness. Six selected panel members scored the product using an arbitrary scoring system of 1 to 10 with 10 indicating excellent, 6 and above Hereafter referred to as fats. acceptable, and below 6 being unacceptable. Scores were determined by tasting a sample from each carcass composed of skin, light, and dark meat. Organoleptic values are based on the average score of the 6 panel members on samples for each variation observed. In Test 1, the remaining halves of each bird were used to obtain chemical analyses for peroxide value at 6 and 9 months and degree of unsaturation of the skin fat and visceral fat and analysis for unsaturated fatty acids at six months only. In Test 2, iodine number of the visceral fat was determined immediately after the birds were processed. Peroxide values were determined immediately after processing and after six months storage. The chemical analysis obtained was based on the results of pooled samples from four birds in each lot for each determination. The skin samples were obtained from half of each carcass from the medial line of the keel bone to the corresponding line along the back, including the skin on the wing and leg. The visceral fat included that attached to the gizzard and that located in the abdominal cavity. Polyunsaturated fatty acids and iodine number were analyzed by A.O.C.S. tentative method Cd 7-8 and Cd 1-25, respectively. Peroxide values were analyzed by method of Rockwood et al. (197). RESULTS AND DISCUSSION In Test 1, comparisons were made on the influence of different fats in the diet of birds on the organoleptic and chemical characteristics of storage poultry. Supplements of 5 percent tallow, 5 percent hydrolyzed soybean fats and 10 percent soybean fats were substituted in the basal ration for equal weights of corn. Comparisons were also made by wrapping these birds in two types of wrapping material, so that storage quality could be

3 STORAGE QUALITY AND RATION FAT 29 TABLE 1. Organoleptic values of chicken receiving added fals in the diet Storage period Treatment * 5% SFJ 5% CFf 10% CF samples 6 months 9 months Aroma Flavor Juiciness * T Tallow. t CF Hydrolyzed cottonseed fats (foots). % SF Hydrolyzed soybean fats (foots). samples Test 1 Packaged in moisture proof vacuumized film Test 1 Packaged by wrapping in wax paper observed under conditions of excellent and moderate freezer protection. The results (Table 1) show that the organoleptic quality of the various groups of birds was not influenced by type of packaging during the storage period. The organoleptic scores (Table 1) for aroma, flavor, and juiciness, indicate that poultry which received additional fats in the diet were comparable to the controls after 6 and 9 months storage. The organoleptic scores were lower after nine months than after 6 months storage, however, all product was still considered acceptable. The results show that the addition of fat to the diet did not increase or decrease the storage life of the experimental groups of poultry from that of the control group. Birds on the control diet and those on the formula supplemented with 5 and 10 percent cottonseed fats and 10 percent soybean fats were compared in Test Test 2 Packaged in moisture proof vacuumized film Aroma Flavor Juiciness These birds were packaged in vacuumized moisture-proof film. The scores for the various organoleptic characteristics were comparable between the different lots for each of the two storage periods (Table 1). All birds were considered acceptable except the flavor score of the birds on 5 percent cottonseed fats and 5 percent soybean fats at 9 months. The addition of different fats and higher levels of the same fat (10 percent) in both tests did not increase or decrease the organoleptic quality of storage poultry compared with poultry fed a commercial broiler ration without added fat. In Test 1, chemical analyses were made on a composite sample of fat from four birds for each treatment (Table 2). The iodine numbers show a variation in the fat deposted by the various diets. Iodine numbers of the skin fat ranged from a low of 9.9 in the lot receiving 5 percent tallow to a high of 79.8 in the lot receiving 5 per-

4 30 M. I. DARROW AND E. 0. ESSARY TABLE 2. Chemical analysis Test 1 Treatment Packaging Insufficient sample. Source of fat cent soybean fats. The iodine numbers of samples of skin fat from birds on 10 percent soybean fats were comparable to the iodine number from samples of skin fat of the group receiving 5 percent soybean fats. The iodine number of visceral fat from birds fed tallow was quite similar to the iodine number of the control. The iodine number of visceral fat from birds receiving hydrolyzed soybean and cottonseed fats was considerably higher than the control. The peroxide values did not reflect deterioration in any group after 6 and 9 months storage. The value for the skin fat samples of birds at 9 months on 5 percent tallow was 12. and for 10 percent soybean fats was 13.. These two samples of higher peroxide values were not detected by the taste panel. Of the three polyunsaturated fatty acids determined, linoleic acid was present in the largest amount in all groups. and visceral fat extracted from birds receiving 5 and 10 percent soybean fats Iodine Peroxide value mos Unsaturated fatty acids () Linoleic Linolenic Arachidonic contained higher levels of linoleic acid than did those receiving 5 percent tallow or control feed. Linoleic acid was deposted to the same extent in the skin fat and visceral fat of the birds in the same lot. Some variation between lots was noted in the levels of linolenic acid, however, all lots showed comparable levels of arachidonic acid. In Test 2 (Table 3) the visceral fat was analyzed for iodine number and peroxide value immediately/ after the birds were chilled in ice slush and for peroxide value after 6 months storage. The peroxide value increased at the 6 months period, Rations 5%CF 10% CF TABLE 3. Chemical analysis Test 2 Source of fats Iodine Initial Insufficient sample. Peroxide value Initial

5 ANNUAL MEETING OF THE POULTRY SCIENCE ASSOCIATION 31 however, none of the samples approached a peroxide value indicating rancidity. It would appear from these data that the organoleptic scores for the characteristics tested were not increased or decreased to any appreciable extent by any of the fats at the levels tested. This was found to be true when packaged under conditions providing excellent and moderate freezer protection. All birds were considered acceptable after 9 months storage. SUMMARY Day old broiler type New Hampshire chicks were distributed at random into four lots of 20 birds each for two different tests. In Test 1, supplements of 5 percent tallow and 5 and 10 percent soybean fats were substituted in the diet for equal weights of corn. In Test 2, supplements of 10 percent soybean fats, and 5 and 10 percent cottonseed fats were substituted as described in Test 1. All birds were fed their respective diets for 10 weeks. At that time four males and four females of each lot were selected at random and processed. Half of the birds in each lot, Test 1, were wrapped in wax paper and the other half in vacuum-type moisture-proof film. Only the latter type of wrapping material was used in Test 2. The birds were frozen and held at temperatures of 9 to 5 F. After 6 and 9/ months storage, two birds of each sex from each lot were used to obtain organoleptic scores and chemical analysis of the skin fat and abdominal fat. All birds were considered acceptable by the taste panel after 9 months storage. Peroxide values obtained from these data did not indicate fat rancidity except in two isolated cases. Different dietary fats appear to deposit different levels of linoleic acid in the birds. It would appear that fats of the type and levels tested may be added to broiler rations without adversely affecting the storage quality of poultry held at 0 F or lower for 9 months. REFERENCES Admundsen, V. S., T. H. Jukes, H. M. Tyler and M. L. Maxwell, The effects of certain fish meals and fish oils in the ration on the flavor of the turkey. Poultry Sci. 17: Barnes, R. H., W. O. Lundberg, H. T. Hanson and G. O. Burr, 193. The effect of certain dietary ingredients on the keeping quality of body fat. J. Biol. Chem. 19: Chu, Ta Kung, and F. A. Kummerow, The deposition of linolenic acid in chickens fed linseed oil. Poultry Sci. 29: Kummerow, F. A., T. B. Avery, R. M. Conrad, G. E. Vail and L. F. Payne, 197. Fat rancidity in eviscerated poultry. Poultry Sci. 26: 58, Kummerow, F. A., J. Hite and S. Kloxin, 198. Fat rancidity in eviscerated poultry. II. The effect of variation in diet on the characteristics of the fat extracted from immature turkeys. Poultry Sci. 27: Kummerow, F. A., G. E. Vail, R. M. Conrad and T. B. Avery, 198. Fat rancidity in eviscerated poultry. V. The effect of variation in diet on the cold storage life of immature turkeys. Poultry Sci. 27: Official and Tentative Methods of the American Oil Chemistry Society. 2nd Edition. Rice, E. E., P. E. Mone, R. E. Gray, R. G. Holleman, Jr. and J. F. Beuk, 195. The value of fat as a feedstuff. Am. Oil Chem. Soc. 21: Rockwood, B. N., J. M. Ramsbottom and V. C. Mehlenbacher, 197. Preparation of animal tissue fats for determination of peroxides and free fatty acids. Ind. Eng. Chem. 19: Scott, H. M., L. D. Matterson and E. P. Singsen, 197, Nutritional factors influencing growth and efficiency of feed utilization I. The effect of the source of carbohydrate. Poultry Sci. 26: 55. Siedler, A. J., and B. S. Schweigert, Effect of feeding graded levels of fat with and without choline and antibiotic plus Bi 2 supplements to chicks. Poultry Sci. 32: Sunde, M. L., 195. The use of animal fats in poultry feed. J. Am. Oil Chem. Soc. 21: -7. AUGUST ANNUAL MEETING OF THE POULTRY SCIENCE ASSOCIATION, MICHIGAN STATE COLLEGE, EAST LANSING.