Effects of dietary vitamin A and zinc on egg yield and some blood parameters of laying hens

Abstract

The purpose of the present study was to examine the effects of vitamin A and zinc interaction in laying hens fed on diets supplemented with two different levels of vitamin A (0, 10.000 IU/kg) in combination with five different levels of zinc (0, 25, 50, 100, 200 mg/kg) on egg yield, plasma and yolk concentration of zinc, and the levels of plasma triglyceride and phosphorus for 12 weeks. Egg production, egg weight, feed intake, body weight and feed efficiency did not differ among the groups. Plasma and yolk zinc concentrations were affected only by zinc supplementation. An interaction between vitamin A and zinc had an effect and the independent effect of vitamin A supplementation increased the plasma triglyceride levels of laying hens. The level of phosphorus in plasma was altered by zinc supplementation and an interaction between zinc and vitamin A. Since the positive relationship between plasma zinc and egg production was observed (r=0.279 p<0.01), it is suggested that plasma zinc may be an indicator for the estimation of egg production or hen performance.

The purpose of the present study was to examine the effects of vitamin A and zinc interaction in laying hens fed on diets supplemented with two different levels of vitamin A (0, 10.000 IU/kg) in combination with five different levels of zinc (0, 25, 50, 100, 200 mg/kg) on egg yield, plasma and yolk concentration of zinc, and the levels of plasma triglyceride and phosphorus for 12 weeks. Egg production, egg weight, feed intake, body weight and feed efficiency did not differ among the groups. Plasma and yolk zinc concentrations were affected only by zinc supplementation. An interaction between vitamin A and zinc had an effect and the independent effect of vitamin A supplementation increased the plasma triglyceride levels of laying hens. The level of phosphorus in plasma was altered by zinc supplementation and an interaction between zinc and vitamin A. Since the positive relationship between plasma zinc and egg production was observed (r=0.279 p<0.01), it is suggested that plasma zinc may be an indicator for the estimation of egg production or hen performance.