Effects of dietary fat type, pentosan level and xylanase supplementation on performance and carcass characteristics of male broilers

A complete two by two by four factorial design was used to examine the main effects of dietary fat type (10% soya oil or 10% beef tallow), xylanase su pplementation (with or without Avizyme 1300 at 1 g/kg diet) and pentosan le vel (calculated values: 7.7 g/kg, 11.0 g/kg, 14.3 g/kg and 17.6 g/kg solubl e pentosans, respectively, by varying wheat/rye proportions) as well as the ir interactions on broiler performance, intestinal viscosity and carcass ch aracteristics. Live weight gain and feed to gain ratio were decreased and i ncreased, respectively, as the dietary pentosan content was increased in a dose-dependent manner independent of fat type and enzyme supplementation. T hese changes were more pronounced in the enzyme-unsupplemented and tallow c ontaining diets. The enzyme effects increased as the rye percentage of the diets increased and were more pronounced in tallow containing diets. Change s in performance were closely related to intestinal viscosity. Slaughter yi elds paralleled the changes observed for fattening performance. In particul ar, the degree of fatness of birds (abdominal plus visceral fat, breast ski n) reflected differences in energy available for lipogenesis inasmuch that a higher degree of fatness was observed at lower pentosan levels and after enzyme supplementation. It is concluded that both dietary fat type and pentosan content of the diet has to be considered when interpreting the effect of dietary addition of x ylanases to broiler feed.