Effect of Culture Conditions on the Levels of Serum Insulin-like Growth Factor-1 in Indian Major Carps

The insulin-like growth factor-1 (IGF-1) plays an important role in the regulation of development and growth of fish. Aquaculture researchers consider it as a potential growth rate indicator. Reports on the IGF-1 of carps are limited. This study was undertaken to determine the serum IGF-1 levels of Indian major carps (IMCs) cultured in the normal pond, sewage-fed pond and captive conditions. Labeo rohita  of the normal pond recorded the highest serum IGF-1 level (2.10±0.14 ng/ml), followed by Catla catla  (1.99±0.17 ng/ml) and Cirrhinus mrigala  (1.82±0.12 ng/ml). Captive held C. catla  recorded the highest serum IGF-1 (2.10±0.19 ng/ml) compared to L. rohita  (2.04±0.08 ng/ml) and C. mrigala  (1.90±0.09 ng/ml). In the sewage-fed pond, C. catla, L. rohita  and C. mrigala  recorded the serum IGF-1 levels of 2.38±0.36 ng/ml, 2.06 ±0.03 ng/ml and 1.07±0.06 ng/ml, respectively. Significant differences existed among the serum IGF-1 levels of C. mrigala  reared in the normal and sewage-fed pond as well as the captive and sewage-fed pond (P < 0.05). It appears from the results that C. catla  and L. rohita  are the ideal cultivable species under the sewage-fed aquaculture. The serum IGF-1 level may be an effective indicator of the differences in growth of carps.