Serum cholesterol level during vitellogenesis of teleost fish, Cyprinus carpio

An attempt was made to study the levels of cholesterol during the vitellogenesis in the ovary of the fish Cyprinus carpio. At least 6 female fish were collected weekly from nearby hatchery during the period February to August transferred to the laboratory live and sacrificed for taking the ovaries for histological examinations. Blood sample (5 ml) was collected from each fish for cholesterol estimation. The vitellogenesis and the gradual increase in serum cholesterol starts (65.50 plus minus 2.0 mg/100ml) in the month of February and reaches it's maximum (98.50 plus minus 4.0 mg/100ml), in mid of March when the ovaries were gravid and ready to spawn. The decline in the serum cholesterol was noted in late March i.e. (75.7 plus minus 2.0 mg/100ml), which continued throughout the month of April. The gradual Increase in serum cholesterol was again noted in early May and reaches to the maximum (93.50 plus minus 5.9 mg/100ml). In early August, the ovaries were again gravid and contained mature follicles which were ready for spawning. The decline in serum cholesterol was also noted as the spawning was over in mid August. The results suggest that the fish may spawn second time if the environmental conditions are conducive.