K. RajiBHUVANA PLAKKOT2022-10-292022-10-292019-12-31https://krishikosh.egranth.ac.in/handle/1/5810189447Thesis Submitted in partial fulfilment of the requirement for the degree of Master of veterinary Science in Veterinary PhysiologyThe difference in prolificacy between high prolific Malabari and low prolific Attappady Black goat breeds of Kerala has been evaluated by gonadotropins and their receptors gene expression studies, and analysis of steroid hormones. Six numbers of experimental animals, each from Malabari and Attappady Black breeds were selected for the study from the culling list of University Sheep and Goat Farm, Kerala Veterinary and Animal Sciences University, Mannuthy. Ovaries, pituitary and serum samples were collected from animals slaughtered at the proestrus stage of the oestrus cycle. By radioimmunoassay technique, a significant difference was observed in serum oestradiol concentrations, with Malabari having a higher mean (44.22±7.00 pg/mL) when compared to the Attappady Black breed (13.98±4.35pg/mL). The ovarian antral follicles were isolated and classified into small (1-3 mm) and large (>3 mm) follicles. RNA isolated from the follicles and pituitaries were used for expression studies. By performing quantitative real-time PCR technique, it was observed that between the breeds, there was no significant difference in the level of FSHβ expression in the pituitary, FSHR expression and LHR expression in follicles. However, there was a significant difference in the pituitary LHβ expression between breeds, with a significantly (P<0.01) high level in Attappady Black compared to Malabari breed. A non-significant decrease in (fold-change of 0.64) FSHR expression and a non-significant increase in (fold-change of 1.4) LHR expression were observed from small to large follicles in goats. Irrespective of breeds, a non-significant negative correlation (-0.49) was observed between oestradiol and FSHβ expression. Also, a non-significant negative correlation (-0.15) was observed between LHβ expression and progesterone concentration. A positive correlation although not very significant was found between FSHβ expression and FSHR expression in goats irrespective of breeds. Similarly, between FSHβ expression and LHR expression in goat antral follicles, a significant positive (P<0.05) correlation was observed. The antral follicle FSHR expression irrespective of breeds, showed a significant (P<0.05) positive correlation (0.46) with the oestradiol concentration. No correlation was found between pituitary overall LHβ and follicle LHR expression in antral follicles irrespective of the breed. A significant (P<0.05) positive correlation was also observed between oestradiol and oestrus signs and Malabari breed exhibited prominent oestrus signs compared to Attappady Black breed.EnglishThesis