Turkish Journal of Fisheries and Aquatic Sciences
2018, Vol 18, Num, 10 (Pages: 1205-1214)
Differential Effects of Heavy Metals (Cadmium, Cobalt, Lead and Mercury) On Oocyte Maturation and Ovulation of the Catfish Heteropneustes fossilis: an In Vitro Study
Geeta J. Gautam 1 ,Radha Chaube 1
1 Banaras Hindu University, Zoology Department, Mahila Mahavidyalaya, Varanasi-221005, India
DOI :
10.4194/1303-2712-v18_10_07
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The aim of the present study was to examine comparative effects of different concentrations of heavy metals such as
cadmium (Cd), cobalt (Co), lead (Pb) and mercury (Hg) on catfish oocyte maturation and ovulation. Post-vitellogenic oocytes
of the catfish H. fossilis were incubated with heavy metals at concentrations of 0.1, 1.0, 10 and 50ng/ml. Translucent follicles
without germinal vesicle and opaque follicles with GV were scored after 4, 8, 16, and 24 hr of incubation. Percentage GV
breakdown (GVBD) was calculated as an index of oocyte maturation. The results of present investigation suggested that the
effect of heavy metals on oocyte maturation and ovulation was in the order of Pb > Hg >Cd>Co. Pb and Hg showed
significant increases (P<0.05) in GVBD and ovulation at all concentrations during 4 and 8hr of the incubation. However, there
was a dose –dependent decrease at 16 and 24hr. Cd and Co showed decline in GVBD and ovulation at 16 and 24 hr of the
incubation. However, mercury and lead showed a stimulatory effect on ovulation at 16 and 24 hr compared to control
(P<0.05). Thus, these results suggest that catfish oocytes are differentially influenced by heavy metals and are resistant to
them at certain levels.
Keywords :
Heavy metals, catfish, ovary, oocyte maturation, ovulation