Response of broiler chicks to L-Glutamine feeding in the immediate pre- and post-hatch periods

This study was conducted to investigate the effects of in ovo and post-hatching supplementation with L-Glutamine (Gln) on hatching characteristics, performance, small intestinal morphology, and muscle development of broilers. At day 18 of incubation, 960 fertilized eggs were allocated to four treatments with six replicates. Eggs were i) not injected (negative control) (NC), ii) subject to the standard incubation procedure (PG), iii) injected with 1 ml sterile solution with 0.9% salt (positive control) (PC), and iv) injected with 1% Gln solution (IG). On hatching, the SC chicks were fed with 1% Gln for seven days. The remaining chicks were fed a commercial starter feed. After hatching, there were six replicates of 28 birds in each treatment. Hatchability and yolk sac weight were lower and yolk-free chick weight (YFCW), whole gastrointestinal tract (GIT) and breast muscle weights were higher at hatching for chicks from the IG treatment. At 42 days old, feed conversation ratio (FCR) was lower in birds that had Gln added to their diet than for the other treatments. The FCR was also lower in IG birds than birds in the NC group. The GIT weight, villus height, villus width and crypt depth of the birds receiving dietary supplementation of Gln were greater than those of birds in PC and IG. Thus, in ovo injection of Gln improved hatching characteristics except for hatchability. Further, in ovo and dietary Gln administration reduced FCR by stimulating digestive system development.