An accurate method of determining the effects of chemical toxicity on reproductive health is through an examination of the histological alterations in fish organs. Thus, a study was conducted to determine the impact of various sub-lethal arsenic concentrations on the histology of the ovary of the Indian catfish, Heteropneustes fossilis. Adult H. fossilis live specimens (body weight 38–47 gm) were purchased from a nearby market and acclimated to lab conditions for two weeks in 50L plastic tanks with 15 fish each. To restrict the fish from jumping out of the tanks, wire nets were used to cover the tanks. The fish were fed commercial dry fish feed pellets at a rate of about 2%–3% of their body weight per day during the acclimatization period. Three groups of fish were created. Groups I and II were subjected to sub-lethal doses of arsenic, i.e., 4 and 8 ppm, prepared from an arsenic stock solution (Merck, Germany), while group III was kept in arsenic-free water to act as a control for 3, 6, and 15 days. Triplicate records for each group were kept.
Histo-pathological Analysis: After 3, 6, and 15 days, small pieces of ovary from each group—group I, II, and III—were taken and immediately fixed in 10% neutral buffered formalin. Routine paraffin embedding preparations were made for fixed tissues. Sections of 5-7 thick were cut from embedded tissues, which were then stained with Harris’ hematoxylin and eosin stains and examined under a microscope. Fish that had their ovary exposed displayed morphological and histological changes. The ovary’s exterior revealed damage to the external layer and a dark brownish green colour. It had more atretic follicles and fewer large and medium follicles, according to histopathology. Fish in the control group displayed no histopathological alterations. Additionally, it was discovered that fish exposed to higher levels of arsenic suffered greater harm.
In conclusion, the current study demonstrated that arsenic toxicity was responsible for the histo-pathological alterations in the ovary of the experimental fish. The outcomes also demonstrated a correlation between the amount of tissue damage and the arsenic concentration.