Effects of Reduced Dietary Crude Protein Diet with Synthetic Amino Acid Supplements on the Growth Performance and Histochemical Characteristics of the Breast Meat of Male Broilers

The present study was conducted to determine the effect of reduced dietary crude protein (CP) with a synthetic indispensable amino acids (AA) supplement on the growth performance, economics, and breast meat quality. A total of 450 male broilers (Ross 308) were used from the age of 7 to 28 days. On d 7, the birds were individually weighed and randomly assigned to three treatment diets with six replicate pens for each treatment in a randomized complete block design. The experimental diets were: (1) a control diet, (2) a diet with a reduction of 1% of the dietary CP with synthetic AA supplements to meet the indispensable AA requirement (OAA) of broiler chickens, and (3) a diet with a reduction of 1% of the dietary CP with synthetic Lys, Met, and Thr supplementation to exceed 5% of the indispensable AA requirement (HAA). There were no differences among the treatments on the final body weight, weight gain, and feed intake. However, the HAA diet impaired the feed conversion ratio at d 21 and during the overall feeding periods ( P <0.05). The predicted total feed intake and feed price required to reached 1.5 kg BW was higher than for the birds fed the HAA diet ( P <0.05). The breast meat muscle fiber cross sectional area and fiber density varied between the treatments ( P <0.05). However, there were no differences in breast meat weight. In conclusion, reducing 1% of dietary CP had no adverse effects on the growth performance or breast meat yields.