Effect of Adding Different Levels of Glycine Amino Acid on Performance, Growth Genes Expression and Immune Status of Broiler Chickens

A total number of 360, day old male broiler chicks were divided into four groups (90 birds each), then each group was subdivided into three replicated (30 bird each), birds were allocated as follow; G1) served as control which fed on the basal diet only (corn-soya based diet) without any dietary treatments, G2) was fed on basal diet fortified with 0.25% glycine from premix, G3) was fed on basal diet fortified with 0.17 % glycine and G 4) was fed on basal diet fortified with 0.08 % glycine from premix. During the observation period (35 days), mortalities and growth performance parameters were weekly recorded as well as, serum samples were collected for detection of antibody titer against (NDV) vaccine. At the end of the trial, the carcass weights, breast muscle & thigh muscle yield, internal organs weights as well as, immune organs weights (spleen, bursa, and thymus) were recorded. Also, liver samples were collected and subjected for RNA extraction to detect IL6, IL1B as inflammatory response indicators, Myogenin, Insulin-like Growth Factor 1 (IGF1) as muscular structure indicators and glutathione peroxidase (GSH-PX) as an antioxidant capacity indicator by using (real-time PCR). The result revealed that, at day 35, the BW, BWG, FI were significantly elevated in G2. G2, G3 and G4 showed better gene expression of Myogenin, IGF1and GSH-Px comparing to G1. Moreover, they appeared the lowest genes expression of IL6 and IL1B. In conclusion, addition of glycine to broiler diet, improves their productivity, increase the muscular structure, enhance antioxidant capacity, and improve immune response.