Ontogenesis of Rectum in Local Awassi Sheep Fetuses (Ovis aris) During Prenatal Periods
Ontogenesis of Rectum in Local Awassi Sheep Fetuses (Ovis aris) During Prenatal Periods
Ali Mobder Niyf*, Jafar Ghazi Abbas Al-Jebori
ABSTRACT
This study aims to investigate the prenatal stages of the rectum in fetuses of Awassi sheep. For this purpose, samples from thirty male and female sheep were taken from the uterus of healthy females, and the crown rump length formula (CRL) was used to classify the samples into four age groups for the prenatal stage. During the first age (50-55) days of gestation, we observed that the rectum wall was slightly wider from proximal part of large intestine, translucent white color and was composed of four histological tunicae: mucosa, pluripotential blastematic layer (submucosa), muscularis externa and finally serosa where the villi are short in height while. At 70-75 days of examination, the rectum was more developed with advancement of gestation and all histological layer was observed with villi in various lengths. At third trimester of gestation (100-105 days and 130-140) days, the rectal villi disappeared, epithelial goblet cells increased in number and density and rectal glands. Tunica muscularis increased in thickness and the mesenchymal layer transformed to connective tissue layer due to differentiation of the most mesenchyme cells to smooth muscle fiber (muscularis interna and muscularis externa). Taken together, the present study showed that the large intestine in local awassi sheep fetuses in the first trimester of gestation was located relatively in the middle part of the abdominal cavity and covered completely by huge liver and where it started to move gradually to the caudal aspect at second trimester, behind the diaphragms, stomach and liver, which appear are translucent wall and whitish in color. On the other hands, at the third trimester of gestation, the wall of large intestine appears elongated musculo-membrenace tube with semi-translucent and with more thickness and different colors from pink to pale-yellow. These finding advanced several aspects of the rectum development and offer several markers to be considered during effective assess of animal health and production potential.
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