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Evaluation of Methods of Processing Dried Poultry Waste in Terms of Performance and Carcass Quality of Broiler Chickens
RESEARCH NOTES Evaluation of Methods of Processing Dried Poultry Waste in Terms of Performance and Carcass Quality of Broiler Chickens A. G. KESE and A. DONKOH
University of Science and Technology, Poultry Section, Kumasi, Ghana (Received for publication December 21, 1981) ABSTRACT Three processing methods, sun drying, roasting, and steam heating of poultry waste, were evaluated for their effect on the chemical composition and microbial population of the resulting dry wastes. They were evaluated further in terms of some physiological parameters using broiler chickens. The method of drying affected significantly the crude protein and crude fiber content of the dried waste. Steam heated and roasted poultry wastes did not produce microbial growth on culturing but sun dried poultry waste contained nonpathogenic Salmonella spp. The feeding of diets incorporating 10% of the variously dried wastes increased final body weight, body weight gain, and feed consumption, as compared to a waste-free (control) diet (P<.05). Feed conversion efficiency decreased, the decrease being significant for the sundried waste diet. Carcass flavor was not significantly different among dietary treatments. Treatment differences in blood cellular elements were not significant. The histological study of the liver revealed no gross tissue changes. (Key words: poultry waste, processing, broiler, performance, blood, tissue) 1982 Poultry Science 61:2500-2502 INTRODUCTION Because of its moisture content and possible contaminants, poultry waste must be processed before it can be incorporated into poultry feed formulations. Current processing methods are complicated and often expensive. In some areas, where the adoption of dried poultry waste as a feed ingredient is almost certain because conventional feedingstuffs are either scarce or expensive, funds for investment in sophisticated facilities may not be available. This points to the need for identifying simple procedures for preparing poultry waste to be used in poultry feeds. The objective of this study, therefore, was to evaluate three simple methods of processingsun drying, steam heating, and roasting—in terms of chemical and bacteriological composition of the waste and the performance and carcass quality of broilers fed diets incorporating the variously dried ingredient. MATERIALS AND METHODS The poultry waste used in the study was collected from caged layers fed a commercialtype layer ration. The collected waste was partially sun dried for 24 hr at an ambient temperature of ca. 30 C and cleaned of extraneous materials such as feathers and feed
particles. Waste was divided into three lots, each lot receiving one of the three different processing methods. Sun drying. Treatment consisted of spreading out a portion of the partially dried waste on a flat metal sheet in the open and sun drying for 2 days at ambient temperatures ranging from 30 to 35 C. Excreta were turned over periodically and collected overnight to protect the waste from being moistened by dew. Steam heating. The apparatus consisted of two 200-liter oil drums, one with solid and the other with perforated bottom. The perforated bottomed drum contained the waste and was placed on top of the other one, which contained water. The drum containing the waste was covered with burlap to conserve the heat. Heat provided by burning logs was applied to the water for 4 hr and the resulting steam rose through the excreta, which attained temperatures reaching 80 C. The excreta were later sun dried for 3 hr. Roasting. The third lot was subjected to dry heat for 2 hr in an open 200-liter capacity oil drum. The excreta was stirred constantly and the temperatures ranged between 102 and 105 C. Each processed lot was ground and stored in burlap sacks until used in formulations. A control diet and three treatment diets (produced by adding 10% of one of the three processed wastes to the control) were fed to
2500
RESEARCH NOTE
commercial strain broiler chickens (Arbor Acre x Ross) for 10 weeks. The waste-free diet was formulated to contain 19% crude protein and 2679 kcal of metabolizable energy (ME) per kilogram. The three diets containing dried poultry waste were calculated to contain approximately 20% crude protein and 2473 kcal of ME per kilogram. At hatching the birds were wingbanded, weighed, and randomly assigned to one of four treatment groups of 48, each subdivided into four replicates of 12 chickens per replicate and housed in 16 pens each measuring 1.67 m . Feed and water were provided ad libitum. Feed consumption, feed conversion efficiency, and body weights were determined on a weekly basis. Proximate analysis was run on the excreta samples from each treatment per Association of Official Analytical Chemists (1970) methodology. Samples of processed excreta were subjected to microbial analysis as described by Zindel (1970). To test for flavor differences between meat from birds fed the different dietary treatments and processed at the end of the study, the paired-comparison test (Merck Technical Bulletin, 1963) was conducted. Blood samples were drawn from the wing vein of 10-wk-old selected birds from different diets and the following parameters were obtained: hemoglobin content, erythrocyte count, leucocyte count, differential leucocyte counts, and packed cell volume (Dacie and Lewis, 1963). Liver sections were examined microscopically for any abnormalities in the cells. Analysis of variance (Snedecor, 1956) was used to identify significance of main effects. Where significant differences were found among treatments, specific effects were tested by the least significance difference procedure. All tests for significance were based on the 5% probability.
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RESULTS AND DISCUSSION
Steam heated poultry waste had a significantly higher crude protein level (20.99%) than roasted (19.87%) and sun dried wastes (19.79%). The crude fiber level of roasted waste was significantly higher than those of the other two. The levels were 22.43% for roasted, 19.74% for sun dried, and 19.38% for the steam heated waste. Steam heated and roasted poultry wastes did
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n o t p r o d u c e microbial g r o w t h o n culturing, b u t sun dried p o u l t r y waste c o n t a i n e d n o n p a t h o genic Salmonella spp. T h e average final b o d y weight and weight gain, as s h o w n in Table 1, indicated significant t r e a t m e n t differences ( P < . 0 5 ) . T h e n u t r i e n t c o m p o s i t i o n of t h e e x p e r i m e n t a l diets and t h e unidentified g r o w t h factor r e p o r t e d t o be contained in p o u l t r y e x c r e t a (Elam et al., 1 9 5 4 ; W e h u n t et al,, 1 9 6 0 ) might have c o n t r i b u t e d t o t h e generally b e t t e r g r o w t h performance achieved b y birds fed dried p o u l t r y waste. Feeding diets incorporating t h e variously dried wastes increased feed consumption significantly ( P < . 0 5 ) a n d decreased feed conversion efficiency (Table 1), t h e decrease being significant for t h e sun dried waste diet. Bhargava and O'Neil ( 1 9 7 5 ) r e p o r t e d similar increased feed c o n s u m p t i o n and feed efficiency deterioration. Tests c o n d u c t e d t o d e t e r m i n e differences in m e a t flavor a m o n g birds from t h e t r e a t m e n t s revealed n o differences. T h e b l o o d cellular elements in t h e chickens, which were all within t h e ranges provided b y Coffin ( 1 9 6 7 ) , revealed n o significant ( P > . 0 5 ) differences a m o n g t r e a t m e n t m e a n s . T h e results o b t a i n e d u n d e r t h e c o n d i t i o n s of
this s t u d y showed n o toxic effects in t e r m s of gross tissue changes in t h e liver.
REFERENCES Association of Official Agricultural Chemist, 1970. Official Methods of Analysis. 10th ed. Washington, DC. Bhargava, K. K., and J. B. O'Neil, 1975. Evaluation of dehydrated poultry waste from cage reared broilers as a feed ingredient for broilers. Poultry Sci. 54:1506-1511. Coffin, D. L., 1967. Normal ranges of blood cellular elements in chickens. Pages 156—157 in Manual of Veterinary Clinical Pathology. 3rd ed. Comstock Publ. Assoc, New York, NY. Dacie, J. V., and S. M. Lewis, 1963. Practical Hematology. 3rd ed. J. and A. Churchill Ltd., London. Elam, J. F., R. L. Jacobs, and J. R. Couch, 1954. Unidentified factor found in autoclaved litter. Poultry Sci. 33:1053-1054. Merck Technical Bulletin, 1963. An introduction to taste-testing of food. Merck and Co., Rahway, NJ. Snedecor, G. W., 1956. Statistical Methods Applied to Experiments in Agriculture and Biology. 5th ed. Iowa State Univ. Press, IA. Wehunt, E. K., H. L. Fuller, and H. M. Edwards Jr., 1960. The nutritive value of hydrolysed poultry manure for broiler chickens. Poultry Sci. 39:1057-1063. Zindel, H. C , 1970. Bacteriological Procedures. Michigan State Univ. Agric. Res. Rep. No. 117: 45-46.
University of Science and Technology, Poultry Section, Kumasi, Ghana (Received for publication December 21, 1981) ABSTRACT Three processing methods, sun drying, roasting, and steam heating of poultry waste, were evaluated for their effect on the chemical composition and microbial population of the resulting dry wastes. They were evaluated further in terms of some physiological parameters using broiler chickens. The method of drying affected significantly the crude protein and crude fiber content of the dried waste. Steam heated and roasted poultry wastes did not produce microbial growth on culturing but sun dried poultry waste contained nonpathogenic Salmonella spp. The feeding of diets incorporating 10% of the variously dried wastes increased final body weight, body weight gain, and feed consumption, as compared to a waste-free (control) diet (P<.05). Feed conversion efficiency decreased, the decrease being significant for the sundried waste diet. Carcass flavor was not significantly different among dietary treatments. Treatment differences in blood cellular elements were not significant. The histological study of the liver revealed no gross tissue changes. (Key words: poultry waste, processing, broiler, performance, blood, tissue) 1982 Poultry Science 61:2500-2502 INTRODUCTION Because of its moisture content and possible contaminants, poultry waste must be processed before it can be incorporated into poultry feed formulations. Current processing methods are complicated and often expensive. In some areas, where the adoption of dried poultry waste as a feed ingredient is almost certain because conventional feedingstuffs are either scarce or expensive, funds for investment in sophisticated facilities may not be available. This points to the need for identifying simple procedures for preparing poultry waste to be used in poultry feeds. The objective of this study, therefore, was to evaluate three simple methods of processingsun drying, steam heating, and roasting—in terms of chemical and bacteriological composition of the waste and the performance and carcass quality of broilers fed diets incorporating the variously dried ingredient. MATERIALS AND METHODS The poultry waste used in the study was collected from caged layers fed a commercialtype layer ration. The collected waste was partially sun dried for 24 hr at an ambient temperature of ca. 30 C and cleaned of extraneous materials such as feathers and feed
particles. Waste was divided into three lots, each lot receiving one of the three different processing methods. Sun drying. Treatment consisted of spreading out a portion of the partially dried waste on a flat metal sheet in the open and sun drying for 2 days at ambient temperatures ranging from 30 to 35 C. Excreta were turned over periodically and collected overnight to protect the waste from being moistened by dew. Steam heating. The apparatus consisted of two 200-liter oil drums, one with solid and the other with perforated bottom. The perforated bottomed drum contained the waste and was placed on top of the other one, which contained water. The drum containing the waste was covered with burlap to conserve the heat. Heat provided by burning logs was applied to the water for 4 hr and the resulting steam rose through the excreta, which attained temperatures reaching 80 C. The excreta were later sun dried for 3 hr. Roasting. The third lot was subjected to dry heat for 2 hr in an open 200-liter capacity oil drum. The excreta was stirred constantly and the temperatures ranged between 102 and 105 C. Each processed lot was ground and stored in burlap sacks until used in formulations. A control diet and three treatment diets (produced by adding 10% of one of the three processed wastes to the control) were fed to
2500
RESEARCH NOTE
commercial strain broiler chickens (Arbor Acre x Ross) for 10 weeks. The waste-free diet was formulated to contain 19% crude protein and 2679 kcal of metabolizable energy (ME) per kilogram. The three diets containing dried poultry waste were calculated to contain approximately 20% crude protein and 2473 kcal of ME per kilogram. At hatching the birds were wingbanded, weighed, and randomly assigned to one of four treatment groups of 48, each subdivided into four replicates of 12 chickens per replicate and housed in 16 pens each measuring 1.67 m . Feed and water were provided ad libitum. Feed consumption, feed conversion efficiency, and body weights were determined on a weekly basis. Proximate analysis was run on the excreta samples from each treatment per Association of Official Analytical Chemists (1970) methodology. Samples of processed excreta were subjected to microbial analysis as described by Zindel (1970). To test for flavor differences between meat from birds fed the different dietary treatments and processed at the end of the study, the paired-comparison test (Merck Technical Bulletin, 1963) was conducted. Blood samples were drawn from the wing vein of 10-wk-old selected birds from different diets and the following parameters were obtained: hemoglobin content, erythrocyte count, leucocyte count, differential leucocyte counts, and packed cell volume (Dacie and Lewis, 1963). Liver sections were examined microscopically for any abnormalities in the cells. Analysis of variance (Snedecor, 1956) was used to identify significance of main effects. Where significant differences were found among treatments, specific effects were tested by the least significance difference procedure. All tests for significance were based on the 5% probability.
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RESULTS AND DISCUSSION
Steam heated poultry waste had a significantly higher crude protein level (20.99%) than roasted (19.87%) and sun dried wastes (19.79%). The crude fiber level of roasted waste was significantly higher than those of the other two. The levels were 22.43% for roasted, 19.74% for sun dried, and 19.38% for the steam heated waste. Steam heated and roasted poultry wastes did
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KESE AND DONKOH
n o t p r o d u c e microbial g r o w t h o n culturing, b u t sun dried p o u l t r y waste c o n t a i n e d n o n p a t h o genic Salmonella spp. T h e average final b o d y weight and weight gain, as s h o w n in Table 1, indicated significant t r e a t m e n t differences ( P < . 0 5 ) . T h e n u t r i e n t c o m p o s i t i o n of t h e e x p e r i m e n t a l diets and t h e unidentified g r o w t h factor r e p o r t e d t o be contained in p o u l t r y e x c r e t a (Elam et al., 1 9 5 4 ; W e h u n t et al,, 1 9 6 0 ) might have c o n t r i b u t e d t o t h e generally b e t t e r g r o w t h performance achieved b y birds fed dried p o u l t r y waste. Feeding diets incorporating t h e variously dried wastes increased feed consumption significantly ( P < . 0 5 ) a n d decreased feed conversion efficiency (Table 1), t h e decrease being significant for t h e sun dried waste diet. Bhargava and O'Neil ( 1 9 7 5 ) r e p o r t e d similar increased feed c o n s u m p t i o n and feed efficiency deterioration. Tests c o n d u c t e d t o d e t e r m i n e differences in m e a t flavor a m o n g birds from t h e t r e a t m e n t s revealed n o differences. T h e b l o o d cellular elements in t h e chickens, which were all within t h e ranges provided b y Coffin ( 1 9 6 7 ) , revealed n o significant ( P > . 0 5 ) differences a m o n g t r e a t m e n t m e a n s . T h e results o b t a i n e d u n d e r t h e c o n d i t i o n s of
this s t u d y showed n o toxic effects in t e r m s of gross tissue changes in t h e liver.
REFERENCES Association of Official Agricultural Chemist, 1970. Official Methods of Analysis. 10th ed. Washington, DC. Bhargava, K. K., and J. B. O'Neil, 1975. Evaluation of dehydrated poultry waste from cage reared broilers as a feed ingredient for broilers. Poultry Sci. 54:1506-1511. Coffin, D. L., 1967. Normal ranges of blood cellular elements in chickens. Pages 156—157 in Manual of Veterinary Clinical Pathology. 3rd ed. Comstock Publ. Assoc, New York, NY. Dacie, J. V., and S. M. Lewis, 1963. Practical Hematology. 3rd ed. J. and A. Churchill Ltd., London. Elam, J. F., R. L. Jacobs, and J. R. Couch, 1954. Unidentified factor found in autoclaved litter. Poultry Sci. 33:1053-1054. Merck Technical Bulletin, 1963. An introduction to taste-testing of food. Merck and Co., Rahway, NJ. Snedecor, G. W., 1956. Statistical Methods Applied to Experiments in Agriculture and Biology. 5th ed. Iowa State Univ. Press, IA. Wehunt, E. K., H. L. Fuller, and H. M. Edwards Jr., 1960. The nutritive value of hydrolysed poultry manure for broiler chickens. Poultry Sci. 39:1057-1063. Zindel, H. C , 1970. Bacteriological Procedures. Michigan State Univ. Agric. Res. Rep. No. 117: 45-46.