Effects of different levels of zinc-glycine and zinc hydroxide on the performance, carcass quality, immunity and duodenum morphometric of the broiler chickens

Abstract

This study was conducted to assess the effect of different levels of zinc hydroxide and zinc-glycine (Zn-Gly) on the performance, carcass quality, immunity, and morphometric of the small intestine. A total of 540 1-day-old Ross-308 broiler chicks were randomly assigned to 9 treatments each having 4 replicates of 15 birds in a 3 × 3 factorial design. They were fed with different amounts of 0, 50 and 100 mg/kg from zinc hydroxide and Zn-Gly. The results showed the significant effect of different levels of zinc hydroxide on performance, carcass quality, immunity and morphometric of the small intestine (p < .05) and also a significant effect of different levels of Zn-Gly on feed intake, feed conversion ratio and thymus (p < .05). The results also showed that when birds were fed with the diet containing 100 mg/kg of Zn-Gly and without zinc hydroxide had the highest weight gain and feed intake, whereas the control diet showed the lowest weight gain and feed intake with a significant difference (p < .05). Overall, the results showed that feeding broilers with a diet containing 100 mg/kg of Zn-Gly had the greatest effect on weight gain, viscera, visceral fat, bursa of fabricius, thymus, spleen, length of the villus and crypt depth. In general, feeding with different levels of organic and inorganic sources of Zn is more effective than the diets without them. HIGHLIGHTS The diet containing Zn-Gly without zinc hydroxide caused a higher increase in weight gain. The used organic sources of Zn in poultry diets are more absorbed compared with the inorganic sources. The difference in Zn absorption between organic and inorganic sources can affect the small intestine.