Effect of arginine, glycine + serine concentrations, and guanidinoacetic acid supplementation in vegetable-based diets for chickens

Abstract

The study investigated guanidinoacetic acid (GAA) supplementation with varying dietary digestible arginine (Arg) and glycine+serine (Gly+Ser) concentrations in the starter phase, exploring respective carry-over effects on growth performance, blood chemistry, incidence of pectoral myopathies and proximate composition in broilers. A total of 2,800 one-day-old male broiler chicks were distributed in a central composite design with 2 factors and double experimental mesh, represented by supplementation or omission of 0.6 g per kg of GAA, with a central point represented by 107% of Arg and 147% of Gly+Ser, 4 factorial points (combinations of Arg/Gly+Ser concentrations: 96.4/132.5%; 117.6/132.5%; 96.4/161.5%, and 117.6/132.5%), and 4 axial points (combinations of axial points estimated for Arg and Gly+Ser, with the central points of 92/147%; 122/147%; 107/126.5, and 107/167.5%), totaling 18 treatments, 4 repetitions to factorial and axial points, 24 replicates to the central point, and 25 birds per pen. Feed conversion ratio (FCR) from d 1 to 10 had a linear response (P = 0.009) for the decreasing Arg content and a quadratic response (P = 0.047) for Gly+Ser concentrations. Broilers supplemented GAA had lower FCR compared with nonsupplemented groups from d 1 to 10 (P = 0.048) and d 1 to 42 (P = 0.026). Aspartate aminotransferase (AST) exhibited increasing and decreasing linear effects as a function of Arg (P = 0.008) and Gly+Ser (P = 0.020) concentrations, respectively. Guanidinoacetic acid decreased serum AST (P = 0.028). Guanidinoacetic acid reduced moderate + severe (P = 0.039) and mild (P = 0.015) Wooden Breast scores. The occurrence of normal White Striping increased (P = 0.002), while severe score was reduced (P = 0.029) with GAA supplementation. In conclusion, increased digestible Arg:Lys and 14% and 6% above the recommendations (107% and 147%), respectively, provided improved FCR during the starter phase. Dietary GAA supplementation (0.6 g per kg) improved FCR, reduced severity of breast myopathies and appears to have reduced muscle damage in broilers fed plant-based diets.

Keywords: amino acid; creatine; muscular dystrophy; white striping; wooden breast.

Figure 1

FCR_0-10d = 3.1226 – 0.0125*Arg - 0,0158*Gly +0.00004*Arg² + 0.00005*Gly² + 0.00001; Significant values are in bold (P < 0.05); Trends are showed with underlined values (P = 0.10).

Figure 2

FCR_0-21d = 1.1057 + 0.087*Arg - 0,0045*Gly - 0.00002*Arg² + 0.00002*Gly² - 0.00003; Significant values are in bold (P < 0.05); Trends are showed with underlined values (P = 0.10).

Figure 3

FCR_0-21d = 1.3624 - 0.043*Arg + 0,0053*Gly + 0.00002*Arg² - 0.00002*Gly² - 0.00002; Significant values are in bold (P < 0.05); Trends are showed with underlined values (P = 0.10).

Figure 4

AST = -3,578.4230 + 38.2811*Arg + 26.7765*Gly - 0.04*Arg² - 0.0344*Gly² - 0.1773; Significant values are in bold (P < 0.05); Trends are showed with underlined values (P = 0.10).

Figure 5

Fat = 114.2747 + 0.5274*Arg – 1.6303*Gly + 0.0008*Arg² + 0.0069*Gly² - 0.0048; Significant values are in bold (P < 0.05); Trends are showed with underlined values (P = 0.10).