The nutritional evaluation of dried poultry waste as a feed ingredient for broiler chickens
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Studies were carried out to determine the chemical and bacteriological compositions of variously dried poultry waste (DPW), and to evaluate DPW as a feed ingredient for broiler chickens. Poultry waste was collected every three days from caged laying hens, and immediately subjected to: (i) oven drying at 60°C; (ii) sun drying followed by autoclaving at 1.05 kg/cm^, 121°C, for 15 minutes or (iii) solar drying at 50-70°C. The differently dried poultry waste showed remarkable similarities in proximate composition, minerals, and amino acid contents, but differed quite significantly in metabolizable energy content, true protein digestibility, and gross protein value. The oven dried waste had a higher metabolizable energy content, true protein digestibility, and gross protein value than the sun dried-autoclaved or the solar dried waste. Most of the bacteria isolated from the dried poultry waste were believed to be normal inhabitants of the chickens' intestinal tract. The dietary inclusion of 5, 10, and 15$ oven dried, sun dried-autoclaved, or the solar dried poultry waste gave no significant differences in growth rate or feed intake of broiler chicks. The 15% level of DPW gave a poorer (P< 0,05) feed efficiency than the 5% level, probably due to the lower dietary metabolizable energy content. In another experiment, lard was included in isonitrogenous diets containing 5, 10, 15 and 20% oven or solar dried poultry’ waste to make the diets isocaloric with the control diet. No significant differences were obtained in growth rate or feed intake of broilers, but feed efficiency was depressed at the 20$ level of DPW inclusion. The dietary inclusion of up to 20$ DPW in broiler diets had no significant effects on carcass yield and meat composition of broilers. No significant differences were observed in broiler performance, carcass yield, or meat composition of broilers fed diets containing 10$ oven or solar dried poultry waste with various dietary energy and protein levels. However, it was cheaper to feed diets with the lowest dietary energy and protein levels. The inclusion of up to 12$ lard in broiler starter diets containing 10$ solar dried poultry waste had no significant effects on broiler performance, or calcium and phosphorus utilization, but the 12$ level of lard caused a significant reduction in magnesium retention. The diet containing 3$ lard gave a significantly higher fat retention than the diet without lard. From the results of this study, it can be concluded that the oven or solar dried layer waste may be safely included up to 15$ of properly balanced diets. Nonetheless, under conditions of this study, the 10$ level of poultry waste appeared to be the most economical maximum limit of inclusion in broiler diets.
SponsorhipUniversity of Nairobi
Department of Animal Science, University of Nairobi