Food-deprivation-induced suppression of pituitary–testicular-axis in the tilapia Oreochromis mossambicus

Abstract

In the present study, the tilapia Oreochromis mossambicus were exposed to food deprivation for a period of 6 or 12 days and changes in the luteinizing hormone (LH) immunoreactivity in the proximal pars distalis (PPD) of the pituitary gland and the testicular activity were examined. Intensely immunoreactive LH content was noticed in the PPD of the pituitary gland in the initial controls, controls on days 6 and 12, and fasting fish on day 6, whereas the LH immunoreactivity was moderate or weak in fasting fish on day 12. In addition, although the mean gonadosomatic and hepatosomatic indices among different experimental groups did not show any statistically significant difference, the mean numbers of spermatogonia, spermatocytes, and spermatids were significantly lower in food-deprived fish on days 6 or 12 compared to those of controls. The inhibition of the spermatogenesis was accompanied by the presence of abundant spermatozoa in the lumen of seminiferous tubules of the testis in food-deprived fish, whereas the occurrence of spermatozoa was relatively infrequent in initial controls and controls. Furthermore, refeeding to food-deprived fish on day 6 onwards resulted in occurrence of few intensely stained LH secreting cells and significantly higher numbers of spermatocytes and spermatids concomitant with sparse spermatozoa in majority of tubules compared to those of food-deprived fish. These results suggest that prolonged exposure to food-deprivation causes suppression of the LH secretory activity in the pituitary gland and disruption in the spermatogenesis in O. mossambicus.

Histology and structure of the testicles in three species of Atelopus frogs (Anura: Bufonidae) endemic to the Sierra Nevada de Santa Marta, Colombia

“…After this period, they were washed in distilled water to remove the excess Boiun. They were then dehydrated in the gradual series of ethanols (70 %, 80 %, 90 %, 96 %) for 4 hours at each step and two final steps in 100 % ethanol, a 4-hour change, and a 12-hour change (Hopwood, 1990;Pikle et al, 2017). Rinsing was carried out in two steps by xylol also at 4 h and 12 h (Guillama et al, 2014).…”