mRNA expression of ANT genes, productive performance and nitrogen excretion of laying hen by feeding low protein diets and amino acid supplementation

The study investigated the effects of low protein diet and amino acid supplementation on production performance of laying hens from 49-57 weeks. A total of 135 chickens were divided into 3 groups: 17% CP, 15% CP and 15% CP supplemented with amino acid (AA). The results showed that the 15% CP group consumed less feed (P<0.01). Adding AA to 15% CP improved feed intake, Met intake, BWG, egg mass (P<0.01) and egg production (P<0.05), while FCR and egg quality were not affected. The percentage of abdominal fat and ANT gene expression were highest in the 15% CP + AA group (P<0.05). Nitrogen retention in manure of 15% CP + AA hens was lower than in 17% CP (P<0.01). These results indicated that the reduced-CP diets supplemented with AA improved production performances and decreased nitrogen excretion.