Effect of supplementing non-starch polysaccharide degrading enzymes with or without protease to corn-soybean meal based diets varying in energy on performance, nutrient utilization, and gut health in broilers

A study was undertaken to develop a suitable NSP enzyme combination through a series of two stage in vitro digestion assay to improve nutrient utilization from corn-soybean meal based diets for broilers and same was assessed in vivo. 360 day old broiler chicks were weighed, wing banded and randomly distributed into twelve experimental groups, six replicates per group and five birds per replicate and raised in electrically heated battery brooders to evaluate the effect of the NSP enzyme combination selected from in vitro studies along with or without protease supplemented to four corn-soybean meal based broiler diets varying in energy concentration. i.e., standard energy (SD) and three low energy diets, [(−75 (LE₁), -150 (LE₂) and -225 (LE₃) kcal lower ME than SD] on performance, nutrient retention, carcass traits, gut conditions and cost economics. Significant (P<0.01) interaction of dietary energy concentration and NSP enzymes was observed for total body weight gain (0–6 weeks). The total weight gain was significantly (P<0.01) higher in enzyme supplemented groups in SD, LE₁ and LE₃. The total body weight gain reduced (P<0.01) with reduction of 225 kcal ME in diet (LE₃) compared to SD. No further improvement was observed with additional supplementation of protease. The feed intake and feed conversion ratio (FCR) significantly (P<0.05) improved with supplementation of NSP enzymes, alone or in combination with protease, irrespective of level of energy. The supplementation of NSP enzymes increased (P<0.05) the organic matter (OM), crude protein (CP), crude fiber (CF), ether extract (EE), nitrogen free extract (NFE) and gross energy (GE) retentions and further improvement was observed with addition of protease. Tibia ash content in broilers was not influenced by either the level of energy or NSP enzymes supplementation. Irrespective of level of energy, enzyme supplementation with or without protease reduced (P<0.05) intestinal pH, viscosity and E. coli count (cfu/ml). Sections of intestines revealed elongated villi with uniform distribution of goblet cell in NSP enzyme supplemented diets fed birds, whereas congested and moderately short ruptured villi were observed in no enzyme fed ones. Dressing and breast yield was un effected by dietary energy but NSP enzyme supplementation increased (P<0.01) the yields. Abdominal fat (%) was lower in LE₂, LE₃, but no effect of NSP enzyme and protease was observed. Feed cost per kg live weight gain for overall period was comparable in SD, LE₁ and LE₂ and decreased (P<0.01) in LE₃. Supplementing NSP enzyme increased (P<0.01) the feed cost of production and further with addition of protease. In conclusion, NSP enzymes combinations derived from in vitro studies may be of some use in improving weight gains and nutrient retention in broilers.