Histomorphometric analysis of the small intestine of broiler chick embryos injected in ovo with methionine

The present study evaluated the histomorphometric effect on the small intestine of the chicken embryo after in ovo methionine injection. On Day 4 of incubation, 50 fertile eggs were allocated into one of the following five groups: control (no treatment) and four treatment groups that received either 20, 30, 40 or 50 mg methionine via their yolk sac. All eggs were incubated until Day 19, at which point the embryos were terminated and 1-cm samples of the duodenum, jejunum and ileum were taken for histology. Sections were stained by haematoxylin and eosin, Alcian blue and periodic acid Schiff methods separately. Morphometric analysis was performed to assess goblet cell number, enterocyte height, muscle-layer thickness as well as villus height, width, area and shape. The ratio of embryo bodyweight to egg weight in methionine treatment groups was more than in controls and this difference was greatest in the 40-mg methionine group. The results showed that villous height, width and area increased in treatment groups, as did enterocyte height, goblet cell number and muscle-layer thickness. The ratio and sequence of the villi was also changed in some treatments. Our results indicated that injecting methionine into the yolk sac can improve intestinal histomorphometrical parameters and that 40-mg methionine injection showed the greatest changes.