The effect of L-lysine in ovo feeding on body weight characteristics and small intestine morphology in a day-old Ross broiler chicks

The aim of this study was to evaluate the effect of L-lysine in ovo injection on hatchability, body weight parameters, small intestine morphology, immune organs, and blood metabolites of one day-old Ross broiler chicks. For this reason, 210 fertile Ross 308 broiler breeder eggs were randomly assigned into 7 treatment groups with 30 eggs per each treatment. Experimental groups included: control (non-injected), sham control (sterile water), 10, 20, 30, 40 and 50 mg lysine in 1ml sterile water, which were injected into the amniotic fluid on 14 d of incubation through the broad end of the egg. On day 22, blood samples were collected from all hatched male chicks, and then they were slaughtered in order to measure body weight parameters and small intestine morphology. The results showed that in ovo lysine feeding up to 20 mg had an increasing effect (P<0.05) on hatchability, carcass efficiency, proportional scalped carcass weight, thigh weight, breast weight, and blood glucose concentration; while a decreasing effect (P<0.01) on serum triglyceride concentration. Despite observing no significant effect of treatments on small intestine weight and length (P>0.05), in ovo lysine injection improved (P<0.05) villus height, crypt depth, villus height/crypt depth ratio of duodenum, jejunum and ileum. The overall results of the present study showed that in ovo injection of L-lysine up to 20 mg had an improving effect on muscle weight, intestine morphology, and blood metabolites of broiler chicks.