Effects of carbohydrase enzyme and non-starch polysaccharids of hull-less barley on performance and eggshell quality in laying hens

Abstract The present experiment was designed to investigate the effects of different levels of commercial enzyme supplemented with diets containing different levels of hull-less barley on performance and egg quality in laying hens. For this purpose, 216 Hy line W36 laying hens were used based on a completely randomized design in 6 experimental treatments with 6 replicates( 6 laying hen per replicate). Treatments were 0, 20, 30, 40, 50 and 60% hull-less barley with three level bioform enzyme with ß-glucanase(550 U/g) and xylanase(800 U/g) (0, 0.5 and 1 g/kg diet). The results of the present experiment showed that the application of the enzyme in the experimental diets had no effect on the measured variables, but its addition to the experimental diets caused a significant reduction in weight and shell thickness and had no effect on other egg quality characteristics. Also, different levels of hull-less barley did not have a significant effect on parameters such as shell thickness and strength, but showed significant differences in terms of yield parameters and some egg quality traits such as egg white, HU and yolk color. Therefore, based on the results of the present experiment, it can be concluded that commercial enzyme did not improve the performance and some quality parameters of eggs and on the other hand reduced the shell quality. The use of hull-less barley in the diet of laying hens caused a decrease in egg quality despite strength shell, also had a negative effect on the yolk color and the thickness of the white egg. The main question is why the commercial enzyme and the hull-less barley reduced the egg shell quality or egg quality despite strength shell?