Nutrient Digestibility, Egg Productivity, and Embryo Development in Laying Hens Fed Bacterial Enzyme-Based Additives

The aim of the experiment was to investigate the effect of microbial enzyme supplements on egg production and the nutrient digestibility of laying hens. a total of 360 twenty-one-week-old hisex brown laying hens were assigned to three treatments with four replicates of 30 birds each using a completely randomized design and reared for 30 days. the treatments consisted of 1) a basal diet provided according to the recommended feeding standards (as the control group), 2) a basal diet supplemented with proteinase enzyme at a concentration of 10 u/kg, and 3) a basal diet supplemented with phytase enzyme at a concentration of 1000 ftu/kg. supplementation of proteinase enzyme increased (p < 0.05) the retention percentage of dry matter and crude protein in laiyng hens compared to the control treatment. and phosphorus retention increased in laying hens by using of the enzymes. the addition of proteinase enzyme to the diet increased body weight gain of laying hens compared to other treatments. feed convertion ratio improved in laying hens recieved enzyme supplements (p < 0.05). the dietary enzymes supplementation increased the egg weight and egg mass than those fed with the enzyme-free diet (p < 0.05). the thickness of eggshell increased by using of phytase enzyme than other treatments. also, ash content of eggshell increased in treatments supplemented by both of the enzymes. according to the results of the experiment, the addition of proteinase and phytase to the diet could be effective in improving the performance of laying hens and the quality characteristics of eggshell.