Annual changes in serum calcium and inorganic phosphate levels and correlation with gonadal status of a freshwater murrel, Channa punctatus (Bloch).

S.K Srivastav,A.K Srivastav

doi:10.1590/s0100-879x1998000800006

Abstract

Adult Channa punctatus murrels of both sexes (60-80 g) were collected locally from Ramgarh Lake during the second week of every month (10 individuals of each sex/month) throughout the year. Blood samples were collected and analyzed for serum calcium and phosphate levels by the methods of Trinder (1960) and Fiske and Subbarow (1925), respectively. Gonads were fixed to judge the state of maturation of the fish. Males exhibited no change in serum calcium levels throughout the year in correlation with testicular maturation. However, serum phosphate levels exhibited a rise in correlation with the increased gonadosomatic index. Females showed marked seasonal changes in serum calcium and phosphate levels which were associated with ovarian maturation (vitellogenesis).

Highlights

Vitellogenesis involves hepatic formation of yolk proteins and raises blood vitellogenin content followed by deposition of two forms of yolk in the ovary: yolk vesicles and yolk granules
No change in serum calcium level was recorded throughout the year (Figure 1A) in relation to testicular cycle
The lowest serum calcium levels were recorded during the resting phase (March and October), with values increasing thereafter and peaking in June and early January (Figure 1A) when the end of the prespawning phase occurs for both reproductive peaks

Summary

Introduction

Vitellogenesis involves hepatic formation of yolk proteins (vitellogenin) and raises blood vitellogenin content followed by deposition of two forms of yolk in the ovary: yolk vesicles (mucopolysaccharides) and yolk granules (phospholipoproteins). Several authors have correlated the increased blood calcium content with ovarian maturation [17]. Estradiol has been shown to stimulate hepatic formation of yolk proteins (vitellogenins) and to raise serum vitellogenin levels and the protein-bound fraction of plasma calcium levels [8,9,10,11,12,13,14,15,16,17,18,19]. In the present study an attempt was made to investigate changes in serum calcium and phosphate levels in relation to ovarian maturation (vitellogenesis) and testicular maturation in a freshwater murrel, Channa punctatus

Methods

Results

Conclusion