ARS | Publication request: Dietary Glycine Needs of Broiler Chicks

Submitted to: Poultry Science
Publication Acceptance Date: March 9, 2004
Publication Date: August 1, 2004
Citation: Corzo, A., Kidd, M.T., Burnham, D.J., Kerr, B.J. 2004. Dietary Glycine Needs Of Broiler Chicks. Poultry Science. 83:1382-1384.

Technical Abstract: Research delineating Gly needs for broilers is sparse. Dietary Gly might become a limiting factor in all-vegetable diets fed to broiler chicks when CP is low. A study was conducted to evaluate dietary Gly needs in broiler chicks from 7 to 20 d of age. Ross 508 male chicks were placed in thirty two floor pens (15 chicks/pen; 5 pens/trt) of a closed-curtain sided house. Chicks were fed a common pre-starter corn-soybean meal based diet (3100 kcal/kg; 23.1% CP; 1.32% Lys) from 1 to 7 d of age, and then fed a titration diet that contained progressive amounts of 0.12% dietary Gly ranging from 0.62% (1.40% Gly+Ser) up to 1.22% (2.00% Gly+Ser) from 7 to 20 d of age. Experimental diets were accomplished by supplementing Gly at the expense of a filler. Using regression analysis (95% of minimum or maximum response), it was calculated that chicks optimized BW gain and feed conversion at 0.98% (1.76% Gly+Ser) and 1.02% (1.80% Gly+Ser) dietary Gly, respectively. Blood plasma free threonine and serine were unaffected by Gly supplementation, but plasma Gly linearly increased. Dietary Gly may need to be considered as a limiting nutrient in early nutrition, especially if CP is low and only vegetable ingredients are used. Present results also suggest that current NRC (1994) recommendations for Gly+Ser of 1.25% may be low.