The Effect of Feather Meal on Carcass Composition and Fat Pad Cellularity in Broilers: Influence of the Calorie:Protein Ratio of the Diet

Abstract

An experiment with a factorial arrangement of treatments was designed to study the effects of feather meal (FM) and the calorie:protein ratio (C:P) of the finisher diet on growth, carcass composition, and the cellular characteristics of the abdominal fat pad in broiler chickens. Four finisher diets were formulated to contain either 0 or 6% FM in combination with C:P of 161 and 186. The diets were available for ad libitum consumption from 35 to 49 days of age.Growth was unaffected by dietary FM at C:P 161 but was reduced at C:P 186, thus indicating a metabolic interaction between the FM and C:P and growth. The FM and C:P 186 each increased carcass yield significantly. Abdominal fat pad weight was not affected by the dietary treatments. Carcass analysis revealed a significant interaction between dietary FM and C:P and carcass weight, protein, and fat. The interaction was manifested as an increase in carcass weight and protein when FM was fed at C:P 161 but a decrease at C:P 186. The change in carcass fat was opposite that of protein at each C:P level. Liver fatty acid synthetase activity was depressed by the feeding of FM. Fat cell number and mean fat cell size were unaffected by either FM feeding or C:P level. These data suggest that dietary FM improves carcass yield and carcass composition, but that the response to dietary FM is influenced by the C:P ratio of the diet.