The productive performance in broilers fed crushed vs. micronized zeolite
The growth efficiency, meat yields and quality, tibial concentrations of macro and micro elements, digestibility and assimilation of dietary nutrients, intestinal morphometry were studied on 4 treatments of Cobb-500 broiler chicks (1 to 36 days of age, 35 birds per treatment) fed crushed (2% of total diet, treatment 2) or micronized (0.2 and 0.5%, treatments 3 and 4) zeolite (clinoptilolite). It was found that the best productivity was in treatments 3 and 4 fed micronized zeolite. Average live bodyweight at 36 days of age in these treatments was higher by 2.4 and 3.1% in compare to unsupplemented control treatment 1, feed conversion ratio lower by 1.8 and 3.0%, digestibility of dietary dry matter higher by 1.9 and 2.8%, protein by 3.0 and 3.4%, fat by 2.5 and 3.0%, nitrogen assimilation higher by 2.1 and 3.5%. Crushed zeolite was less effective compared to the micronized one. There were no differences between the treatments in the digestibility of dietary calcium and phosphorus; tibial concentrations of ash, Ca, P, Fe, Mn, Cu, and Zn; deposition of vitamins A, E, and B2 in liver; chemical composition of leg and breast muscles. The yield of breast meat (related to the eviscerated carcass weight) in treatments 3 and 4 was higher by 1.2 and 1.6% in compare to control. Supplementation of diets with zeolite improved the intestinal functionality in broilers due to the increases in average villus height and crypt depth.