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Unformatted text preview: ¬° INTRODUCTION¬° The nonprotein synthesis roles of Gly are as a precur- sor to glutathione, nucleic acid bases, heme, creatine, and bile acids along with methyl group metabolism (Reeds and Mersmann, 1991). These roles along with Gly being a component of uric acid and protein struc- ture make it an essential amino acid for poultry. The supplementation of Gly to a 16% CP broiler starter diet restored growth performance similar to a positive control diet (Dean et al., 2006). Further investigation within our laboratory showed that Gly supplementa- tion improved feed efficiency of broilers fed a typical corn and soybean meal ( C-SBM ) diet that was ad- equate in all nutrients (Waguespack et al., 2008). Simi- lar improvement in feed efficiency was also observed in reduced CP diets with varying levels of Lys and TSAA (Powell et al., 2009). The increase in G:F that resulted from Gly supplementation was not always accompanied by increased ADG, indicating that the increased G:F observed in these reports was not always the result of increased protein synthesis, but of increased utilization of nutrients. All diets that responded to Gly supplementation in our laboratory had a dietary Cys level of 0.34 to 0.35%. This level of Cys is lower than the 0.40% recommended for 0- to 21-d-old broilers (NRC 1994). Also, within the literature, differences exist in the reported Cys re- quirement for broilers within the 0- to 21-d age range. Kalinowski et al. (2003) reported that the Cys require- ment for 0- to 21-d-old male broilers ranged from 0.39 to 0.44% of the diet depending on the rate of feath- ering, whereas Moran (1980) reported a Cys require- ment of 0.41 and 0.46% Cys for 0- to14-d-old male and female broilers, respectively. These reports (Moran, 1980; Kalinowski et al., 2003) indicate that the level of Cys in the diets that responded to Gly supplementa- tion (Waguespack et al., 2008; Powell et al., 2009) was Effects of glycine supplementation at varying levels of methionine and cystine on the growth performance of broilers fed reduced crude protein diets 1 S. Powell, T. D. Bidner, and L. L. Southern 2 School of Animal Sciences, Louisiana State University Agricultural Center, Baton Rouge 70803 ¬°ABSTRACT¬°¬° Two experiments were conducted to inves- tigate Gly addition to reduced crude protein corn‚Äďsoy- bean meal (C-SBM) diets with varying levels of TSAA achieved by varying Met and Cys. The experiments were conducted with female Ross 708 broilers in brood- er batteries from 0 to 18 d posthatching. Treatments had 6 replicates with 6 broilers/pen. Diets in all experi- ments were fed without or with Gly supplementation to contain 2.32% total Gly + Ser. All diets were C-SBM based and formulated to contained 1.27% standard- ized ileal digestible Lys supplemented with 0.20% Lys (0.394% Lys¬∑SO 4 ) and to meet or exceed the require- ment of all nutrients except Met and Cys where appro- priate. Experiment 1 consisted of 8 dietary treatments....
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This note was uploaded on 07/28/2011 for the course VET 4335 taught by Professor Sakomura during the Spring '11 term at University of the South Pacific, Fiji.
- Spring '11