摘要
The objective of this research was to update current results about the nutrient composition of broiler chickens during the growth period up to market age. Two growth experiments were conducted for assessing the nutrient content of feathers and feather-free body of meat-type chickens (Ross 308). Both male and female birds were reared under uniform management conditions (floor pens;15 pens per gender;5 birds per pen). Experimental diets both for the starter (day 1 to 22) and the grower period (day 22 to 36) were based on corn, wheat, soybean meal, soybean protein concentrate and well balanced with feed amino acids. The feed protein quality was adapted to the ideal amino acid ratio and equated within both of the feeding periods by adjusting a constant mixture of the feed proteins. Each 15 birds per gender (3 pens of 5 birds) were selected and subsequently fasted for 24 h before quantitative de-feathering both at start of the experiment and further on weekly up to the end of the 5th week. Nutrient content was determined in representative samples of the feather and feather-free body fraction. In the feather dry matter (DM) very high crude protein (CP) concentrations (>96%) with low age-dependent and insignificant gender-specific differences were observed. In spite, a relatively high variation of CP content in the DM of feather-free body was found. Depending on age, the body CP significantly decreased with increasing age, but male birds yielded higher (p < 0.001) CP content. The crude lipid content of the feather-free and whole empty body significantly increased with age and was higher in female as compared to male birds (p < 0.001). Depending on age and gender, the crude ash content both in feathers and feather-free body of modern fast-growing chickens was rather low and with very low variation.
The objective of this research was to update current results about the nutrient composition of broiler chickens during the growth period up to market age. Two growth experiments were conducted for assessing the nutrient content of feathers and feather-free body of meat-type chickens (Ross 308). Both male and female birds were reared under uniform management conditions (floor pens;15 pens per gender;5 birds per pen). Experimental diets both for the starter (day 1 to 22) and the grower period (day 22 to 36) were based on corn, wheat, soybean meal, soybean protein concentrate and well balanced with feed amino acids. The feed protein quality was adapted to the ideal amino acid ratio and equated within both of the feeding periods by adjusting a constant mixture of the feed proteins. Each 15 birds per gender (3 pens of 5 birds) were selected and subsequently fasted for 24 h before quantitative de-feathering both at start of the experiment and further on weekly up to the end of the 5th week. Nutrient content was determined in representative samples of the feather and feather-free body fraction. In the feather dry matter (DM) very high crude protein (CP) concentrations (>96%) with low age-dependent and insignificant gender-specific differences were observed. In spite, a relatively high variation of CP content in the DM of feather-free body was found. Depending on age, the body CP significantly decreased with increasing age, but male birds yielded higher (p < 0.001) CP content. The crude lipid content of the feather-free and whole empty body significantly increased with age and was higher in female as compared to male birds (p < 0.001). Depending on age and gender, the crude ash content both in feathers and feather-free body of modern fast-growing chickens was rather low and with very low variation.
