The effect of in ovo feeding of DL-methionine on small intestine morphology in a day-old broiler chicks

In ovo feeding is considered as a useful tool to overcome the growth limitations during embryonic growth and after hatching in domesticated poultry. Therefore, the purpose of the present study was to investigate the effect of different levels of DL- methionine on the morphology of small intestine in ROSS 308 broiler chicks. In this regard, the total number of 240 eggs from Ross 308 broiler breeder were used according to a completely randomized design (CRD) with 8 experimental groups and 30 eggs per each treatment. The experimental treatments included different levels of DL-methionine amino acid (0.19, 0.38, 0.57, 0.76, 0.95 and 1.14 %), along with a sham-control group (sterile water injection) and a control group (without injection) which were injected into the amniotic fluid on the 14th d of incubation. After hatching, the chicks were weighed and slaughtered to measure small intestine morphological characteristics. Results of the study indicated that in ovo feeding of DL-methionine had a significant effect (p<0.05) on hatchability, weight and relative weight of jejunum, small intestine weight, as well as crypt diameter (except for duodenum), villus height, crypt depth, villus height to crypt depth ratio, and villus thickness in duodenum, jejunum, and ileum. On the other hand, no effect of treatments (p>0.05) was observed on chick weight and weight and length indexes of duodenum and ileum. Based on the results of this study, the best morphological response was observed in 76% DL-methionine treatment.