Dietary nutritional density, calcium pidolate, and lysine source on performance, occurence of myopathies and other carcass quality properties in broilers

Abstract

The objective of this study was to evaluate the effects of dietary lysine source (Lys-HCl and Lys-SO4), calcium pidolate (presence and absence), and nutritional density (high and low) on the performance, cut yields, rates of the wooden breast (WB) and white striping (WS) myopathies, meat quality parameters, and chemical composition in broilers. A total of 1,440 one-day-old Cobb 500® male chicks from a commercial hatchery were distributed in a completely randomized design into 48 plots, and eight treatments were evaluated in a 2 × 2 × 2 factorial arrangement (lysine sources × calcium pidolate presence/absence × nutritional densities), with six replicates per treatment. Feed intake (FI), weight gain (WG), and feed conversion (FC) were evaluated at 21 and 42 days of age. The carcass characteristics evaluated were the carcass (CY), breast (BY), leg (LY), wing (WY), and abdominal fat yields (AFY). The WB and WS myopathies were assessed by three evaluators according to the degree of severity in breast fillets. Meat quality was measured by drip loss, pH, colour (L*, a*, b*), cooking loss, and shear force. The chemical composition of the breast fillets was determined by the percentages of dry matter, protein, collagen, fat, and mineral matter. The data were subjected to analysis of variance and the F-test at 5 % significance. WB and WS were analysed using the Kruskal-Wallis test at 5 % significance. Broiler performance was influenced (p < 0.05) only by nutritional density: Higher WG, lower FI, and better FC were found with higher nutritional density. The treatment did not influence (p > 0.05) CY, BY, LY, WY, or AFY. A difference (p < 0.05) in the rate of the myopathies was observed. Higher rates of WB and WS were observed in breast fillets of birds fed diets containing Lys-HCl. There was an interaction effect (p < 0.05) of nutritional density and calcium pidolate on the a* and b* colour parameters. A high-nutritional-density diet improved broiler performance without predisposing them to myopathies. The rate of the WS myopathy was higher (p < 0.05) when Lys-HCl was used than when Lys-SO4 was used. The addition of calcium pidolate to the diet of broilers aged ≤21 days reduced (p < 0.05) the rate of WS in breast fillets. Thus, the use of high-performance diets does not increase myopathies, and the addition of calcium pidolate and Lys-SO4 helps avoid problems.