The nutrition of meat-type ducks. 3. The effects of fibre on biological performance and carcass characteristics

Abstract

Three experiments were conducted with male ducks and male broiler chickens to study the effects of dietary fibre on biological performance. Vegetable oil and dextrose were used to maintain diets isonitrogenous and isoenergetic in experiment 1. Both species had higher weight gains, dressed carcass weights and better feed conversion ratios (FCR) on the higher fibre and higher oil-based diets, but determined metabolizable energy (ME) was also higher on these diets. In experiments 2 and 3, weight gain was the same but feed intake and ME intake were higher, and FCR was poorer on the diets with highest fibre content. Dietary ME was lowest on these diets. Ducklings required more ME per g gain than did chickens, but utilized it more efficiently than did chickens. In both species fibre appeared to reduce availability of ME. Ducklings had less protein and more fat in the carcass than chickens. For both species, fat content of the carcass decreased and protein content increased with increasing amounts of fibre in the diet. Neither species was able to utilize dietary fibre; negative digestibility values were obtained consistently.