Nutritional modulation of live performance and meat yield must be continuously tested as broiler strains become more efficient every year, according to Mi Yuling of Zhejiang University in China and co-authors there and at the University of Arkansas in the US.

In the Journal of Applied Poultry Research, they report a study to evaluate both copper- and lysine-derived amino acid balance.

In experiment 1, amino acid balance (high, moderate and low) and copper (5 and 200ppm) were investigated in a factorial array of treatments (six treatments with eight replicates; 1,536 Cobb 500 male broilers across 48 floor pens from one to 40 days of age; 32 birds per pen).

In experiment 2, amino acid density (high and low) was assessed in two broiler strains (a multipurpose and a high-yield strain) obtained from the field in a factorial array of treatments (four treatments with 21 replicates; 1,344 multipurpose and 1,344 high-yield broilers across 84 floor pens from one to 42 days of age; 32 birds per pen).

Amino acid density treatments were created by altering digestible lysine and other essentials amino acids at a fixed ratio.

Copper and amino acid density did not interact, the researchers found, but supplementing broilers with 200ppm of copper in the form of tribasic copper chloride improved growth rate.

Lysine-derived amino acid density improved performance and yields but should be assessed as strains are improved for efficiency to ensure digestible lysine adequacy in the nutrient formulation matrix, according to Mi and co-authors. Although both copper and lysine influence growth rate, they added, interactive effects were not assessed in their study.

Reference

Wang H., C. Zhang, Y. Mi and M.T. Kidd. 2014. Copper and lysine amino acid density responses in commercial broilers. J. Appl. Poult. Res. 23: 470-477. doi: 10.3382/japr.2014-00959

November 2014