Evaluation of substrate specific non-starch polysaccharide enzymes in commercial layer diets containing alternate protein supplements

A study was undertaken on 2490 commercial layers to evaluate the possibility of soybean meal (SBM) replacement with alternate protein supplements (APS) in isocaloric diets supplemented with substrate specific NSP enzymes. A corn/SBM diet was prepared as a control and two APS diets were prepared by replacing 44 and 87% of SBM by weight in control diet with cotton seed meal (CSM), rapeseed meal (RSM) and guar meal (GM) at two levels i.e., 5, 2.5 and 3% respectively, in APS1 and 10, 5 and 6%, respectively in APS2. Dietary specific NSP enzymes [Xylanase (X), α-D-glucanase (G), mannanase (M), cellulase (C) and pectinase (P)] combinations, E1 comprising X-700, G-1400, M-1000, C-100 and P-2000 IU/kg for corn/SBM; E2 comprising X- 2100, G-2800, M-1000, C-3000 and P-7000 IU/kg for APS1 and E3 comprising X-40000, G-10000, M-6000, C-1900 and P-10000 IU/kg for APS2 diets were supplemented. The enzymes in E1, E2 and E3 were selected based on soluble sugars in APS and their concentrations were selected based on in vitro and metabolic studies. Egg production, egg mass and feed efficiency were not affected by feeding on corn/SBM and APS1 diets with or without enzyme (E1 and E2) supplementation, but it was significantly reduced (P<0.01) in APS2. However, enzyme (E3) addition to APS2 significantly improved (P<0.01) all three parameters. Feed intake was significantly reduced (P<0.05) in enzymes supplemented corn/SBM diet, while it was comparable in other dietary groups. Egg quality and serum biochemical constituents were not affected among all treatment groups. Highest feed cost per dozen eggs was recorded (P<0.01) for corn/SBM diet and it was significantly reduced (P<0.01) in APS1 and APS2, while lowest (P<0.01) was recorded in enzymes (E3) supplemented APS2. It was concluded that SBM in traditional commercial layer diets can be safely replaced with APS (CSM-10, RSM-5 and GM-6%) up to 87% by supplementing substrate-specific NSP enzymes (X-40000, G-10000, M-6000, C-1900 and P-10000 IU/kg). However, without enzymes, SBM in commercial layer diets can be replaced up to 44% with APS comprising CSM-5%, RSM-2.5% and GM-3%.