Comparative Histological Observation of Liver Tissue Before and After Reproduction in Male and Female Frogs (Pelophylax ridibundus)

Abstract

Histomorphological structure of the liver of Ranidae species during the reproduction period contribute significantly to the production rate in the frog culture studies. In this study, the cytoplasmic status of hepatocytes, lipid and melanin pigment in liver parenchyma of adult male and female Pelophylax ridibundus (Pallas, 1771) were investigated before and after reproduction. For histological studies, adult frogs were collected from nature and placed in production ponds to examine the reproduction process. In this study, twenty four breeding male frogs, with average weight 36.63 +/- 12.84 g and length 69.29 +/- 9.15 mm, and twenty four breeding females with average weight and length of 56.61 +/- 19.59 g and 79.54 +/- 7.07 mm were used. Samples from the liver tissue of frog were taken in 2015 during (March) and after reproduction (June) period. Histologically pictures of liver parenchyma were taken from the as homogeneous fields as possible. Before the reproduction, it was found that the liver parenchyma of the female frogs were cytoplasmically intense, with a low amount of melanin pigment and lipid droplets. Similarly, male frogs liver parenchyma and hepatocytes were found to be cytoplasmically intense, containing a low amount of melanin pigment and lipid droplets. Both female and male frogs completed the reproduction in April and May. After reproduction period, a great amount of melanin pigment in the liver parenchyma was observed and the cytoplasmic density of the hepatocytes decreased. As a result, cytoplasmic decrease in hepatocytes, structural changes and increase in melanin pigments supports the idea that glycogen and lipids stored in the liver parenchyma are used for reproduction.