Dose-dependent effect of dietary zeolite on laying hens’ performance

This study aimed to evaluate the effect of adding zeolite to Fayoumi laying hens’ diets on productive performance, egg quality characteristics, carcass characteristics, litter quality, and gut microbiota. Three hundred and sixty Fayoumi layer hens (40 weeks old) were randomly allocated to four experimental groups, with three replicates per group (30 hens/replicate). The hens were fed a basal diet supplemented with 0 (control), 10, 15, or 20 g zeolite/kg, and the experiment lasted for 16 weeks. The results displayed that the addition of zeolite substantially enhanced ( P < 0.001) body weight (BW), weight gain (BWG), growth rate, and feed conversion ratio (FCR) in a dose-dependent manner, however, also lowering feed intake (FI). Birds fed diets provided with 20 zeolite g/kg showed the highest final BW (2055.00 g) and the highest overall growth rate (8.62%), accompanied by the lowest FCR (3.17). Carcass attributes also significantly improved, with increased weight of the carcass, liver, heart, gizzard, and edible parts, and a notable reduction in abdominal fat weight ( P < 0.001). Egg production parameters, involving egg number, weight, mass, and laying rate, substantially improved in all zeolite-treated birds, with the best results yielded at a level of 20 g/kg. Moreover, Egg quality traits were also significantly enhanced ( P < 0.001), such as yolk, albumen, and shell weight, eggshell thickness, Haugh units (HU), yolk index, and shape index. Regarding litter quality, it was observed that zeolite addition resulted in a substantial reduction in NH 3 concentrations, pH, and moisture content in litter. Besides, it positively enhanced gut microbiota health by lowering the total bacterial count, coliforms, E. coli , and Salmonella , whereas augmenting Lactobacillus counts. These results prove that dietary zeolite, remarkably at a level of 20 g/kg, is an applicable natural feed additive for enhancing productivity, egg quality, overall health, and gut microbiota in Fayoumi layer hens.