Effects of rice bran-nonstarch polysaccharides and fiber-degrading enzymes on performance and nutrient digestibility in broiler chicks

This experiment was conducted to study the effect of varying levels (0, 4, and 7% ) of total nonstarch polysaccharides (NSP) prepared from defatted rice bran on performance, nutrient digestibility, and energy value of the diet in the 1- to 14-d-old broiler chicks. Two of the 7 %-NSP diets were supplemented with LAMINEX XL supR (3,080 units xylanase/kg of diet), or LAMINEX XL supR plus LAMINEX BG supR (366 units beta-glucanase/kg of diet). All diets contained 3.00 Meal of metabolizable energy (ME sub(n) )/kg of diet and 22 % of crude protein. The results showed that feeding chicks a diet containing up to 7 % of NSP had no effects on feed intake, body weight gain, feed : gain ratio, and fat digestibility. However, chicks receiving the 7%-NSP diet showed a greater protein digestibility compared with those receiving the 0%- or the 4%-NSP diet at d 7 (P<0.01) or with those receiving the 0%-NSP at d 14 (P<0.05). Dietary 7%-NSP depressed pancreatic lipase activities at d 14. Although this depressing effect was ameliorated with xylanase or xylanase plus beta-glucanase supplementations, the supplemental enzymes did not improve fat digestibility that was adversely affected (P<0.01) by 7 % of NSP in the diet on d 14. Xylanase improved protein digestibility of the 7%-NSP diet on d 7 (P<0.05), and xylanase plus beta-glucanase also showed an improving effect on d 14 (P<0.05). The supplementation of enzyme did not influence the ME sub(n) values of the diet. The results of the present study suggest that at up to 7%, NSP of defatted rice bran possesses no antinutritive effects on nutrient digestibility, but positively influences the ME sub(n) value of the diet. The favoring effect of enzymes on protein digestibility did not contribute to the performance of the chicks at early age.