Histological, Histochemical and Micrometric Studies on the Embryonic Gall Bladder of Gaddi Sheep in Different Prenatal Age Groups

The objective in the present study was to explore the histological, histochemical and micrometric changes of developing gall bladder during the fetal life of Gaddi sheep. A total number of 40 Gaddi sheep foetii samples were collected irrespective of sex and without any external anomaly or pathology. The age estimation of each foetus was done and accordingly the foetii were grouped as; group-I (1-60days), group-II (61-90days) group-III (91-120days) and groupIV (121 –full term). The gall bladder from each foetii were excised hygienically. Gall bladder appeared at CRL 6.0 cm (46 days of gestationl age). At CRL 11.0 cm (60 days of gestational age) the tunica mucosa, tunica submucosa, tunica muscularis and tunica serosa layers were clearly distinguishable. The lamina muscularis was absent in prenatal gall bladder in all stages of gestational age. The thickness of tunica muscularis, tunica serosa and luminal diameter of gall bladder also increased significantly with the advancement of gestational age. The non-ciliated simple columnar epithelium cells were covered by the discontinuous to continuous striated border of microvilli at CRL 24.5 cm (97 days of gestation) which became continuous at CRL 42.5 cm (146 days of gestational age). Strong reaction for proteins was observed in all layers of gall bladder at CRL 32.0 cm (117 days of gestation). Strong PAS positive reaction was observed by tunica mucosa layer of gall bladder while the rest of its layers showed moderate reaction for PAS near full term. The reaction for proteins was mild at early stages development of gall bladder, which became strongest at CRL 32.0 (117 days of gestational age) in all layers of gall bladder.