EXPRESSION OF GONADOTROPINS AND THEIR RECEPTORS IN ATTAPPADY BLACK AND MALABARI GOATS
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Date
2019-12-31
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COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR,
Abstract
The 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.
Description
Thesis Submitted in partial fulfilment of the requirement for the degree of Master of veterinary Science in Veterinary Physiology