The morphological characteristics of the Meckel’s diverticulum of pre-hatch and post-hatch broiler chicken

Abstract

Morphology of the Meckel’s diverticulum (MD) of broiler chicken was investigated using gross anatomical, histological and transmission electron microscopy techniques. Forty fertile eggs and 100 chicks of Marshall broiler chicken were used for the study. Samples were collected from 6 randomly selected embryos or chicks on embryonic days 14, 17 and 19, and post-hatch days 1, 3, 5, 7, 14, 21, 28, 35, 42 and 56. The results showed that the mean lengths of the small intestine from the gizzard to the MD and from the MD to the ileocecal junction increased steadily with age. On embryonic days 14, 17 and 19, the poorly differentiated tunics of the MD were composed of lamina epithelialis mucosae and indistinct lamina propria mucosae as well as submucosal areas. The tunica muscularis exhibited loose islands of nascent smooth muscle fibres. Whereas on post-hatch day 1, the lamina epithelialis mucosae showed scanty microvilli and enterocytes with large cytoplasmic vacuoles, the MD of 3-day-old post-hatch chicks contained lymphatic tissues in the lamina propria mucosae. On post-hatch day 35, the lamina epithelialis mucosae demonstrated the presence of apoptotic cells while numerous lymphocytes at various stages of differentiation were observed within the lamina propria mucosae and tunica submucosa. In conclusion, the present study has provided clear structural evidence which shows that intense cellular proliferation occurs in the MD of broiler chicken between embryonic days 14 and 19. This organ may play significant roles in immunological surveillance of the gut, and such functions may peak on post-hatch day 35.