Effect of glycine equivalent levels in low protein diet containing different SID threonine concentrations on performance, serum metabolites and muscle creatine of broiler chickens

This study was conducted to evaluate glycine equivalent (Glyequi) requirement in low crude protein (CP) diets with different levels of standardised ileal digestible (SID) threonine (Thr) on performance, serum metabolites, and muscle creatine broiler chickens from 1 21 d age. A total 1275 one-day-old male Cobb-Vantress chicks were distributed a completely randomised 3 × 5 factorial arrangement for 15 treatments replicates 17 birds each. Diets formulated comprise three dietary SID Thr concentrations 6.9, 8.1 9.3 g/kg five Glyequi (12.8, 14.3, 15.8, 17.3 18.8 g/kg). An interaction (p < 0.05) observed between the feed:gain uric acid (SUA). With increasing Glyequi, decreased linearly 6.9 while SUA diet. In diet containing Thr, level optimised = 0.04) at an estimated minimum 15.5 g/kg. resulted quadratic effect (P BWG, feed:gain, optimum point 17.2, 16.7, 17.1 g/kg, respectively. Therefore, CP (174.0 g/kg) needed performance is diet, but could be or higher than 20.9 broilers.HighlightsFeeding low-protein 174 adequate concentration support broilers 1–21 old.Provision required improve performance.Sufficient supply represents sparing Gly especially marginal low-CP diets.