the effect of different levels of minerals and vitamins premixes on performance of laying hens fed by wheat and corn base diets

this experiment was conducted to evaluate effects of different levels of mineral and vitamin premixes with wheat and corn base diets on performance and egg traits of laying hens. experiment carried out as 2*5 factorial include wheat and corn base diets and 5 levels of minerals and vitamin premixes (0, 0.25, 0.35, 0.45 and 0.55 percentage) in a completely randomized design with 360 hi-line (w36) laying hens from 65 to 77 weeks in 10 treatments, 3 replicates and 12 hens in each replicate for 12 weeks. the results showed that diets composition, level of mineral and vitamin premixes, and interaction between them significantly affected the performance and egg traits of laying hens (p<0.05). in wheat base diet in contrast with corn base diet, egg production, egg mass, feed intake and feed cost for production per kilogram of egg decreased whereas feed conversion ratio increased. the highest amounts of egg weight, egg production percentage, egg mass and the best feed conversion ratio were observed by using 0.55% of minerals and vitamin premixes. the highest amounts of egg production percentage, egg mass, the best feed conversion, and the lowest feed cost per kilogram of egg were obtained by using 0.55% of minerals and vitamin premixes on wheat base diets. adding 0.55% of minerals and vitamin premixes in wheat- base diet increased the percentage of albumin and decreased the percentage of yolk egg. the overall results of the present study indicated that in laying hens diets replacing of corn with wheat and adding 0.55% of minerals and vitamins premixes improve their performance and decreased egg production cost.