Resumen de Effects of wheat cultivar, metabolizable energy level, and xylanase supplementation to laying hens diet on performance, egg quality traits, and selected blood parameters
Masoud Mirzaee, Mehran Torki, Mahmood Habibian
A 2 × 2 × 2 factorial arrangement of treatments was conducted to evaluate the effects of two dietary apparent metabolizable energy (AME) levels (2,720 and 2,580 kcal kg�1 diet) and enzyme (0 and 0.3 g kg�1 diet, Grindazym® GP 15,000 with mostly xylanase activity) supplementation on the performance of laying hens fed diets based on two wheat cultivars (Marvdasht and Sardari). Experimental diets were formulated to have a constant energy to protein ratio and were fed to 65-wk-old Lohmann LSL-Lite laying hens for 7 wk. The lower level of AME reduced egg production and egg mass (p < 0.05) and increased feed conversion ratio (p < 0.05). Enzyme addition increased feed intake of the birds fed a diet with Sardari cultivar (p < 0.05) but had no effect on feed intake of the birds fed a diet with Marvdasht cultivar (p > 0.05). Nevertheless, birds receiving diets based on Marvdasht cultivar had higher feed intake and egg mass than that of those receiving diets based on Sardari cultivar (p < 0.05). The birds fed diets based on Marvdasht cultivar produced less undesired eggs and had better yolk color as compared with the birds fed diets based on Sardari cultivar (p < 0.05). The serum concentration of glucose increased by enzyme supplementation when birds receiving lower AME level (p < 0.05). These results indicate that enzyme supplementation may have a positive effect on the feed intake of laying hens when fed on wheat-based diets; however, this effect is cultivar dependent and does not necessarily mean that enzyme supplementation always benefit production.
