Variations in hepatosomatic index and biochemical profiles among the male morphotypes of Macrobrachium rosenbergii

Hepatosomatic indices and biochemical profile of the male morphotypes of Macrobrachium rosembergii such as small males, weak orange clawed males, strong orange clawed males, pre-transforming strong orange clawed males, weak blue clawed males, strong blue clawed males of grow-outs and old blue clawed males from the Vembanad lake were studied. Size characterization of M. rosenbergii agreed with the earlier reports. A marked variation in hepatosomatic index (HSI) of morphotypes indicated the possibility of differences in food assimilation and growth rates. Mean HSI values were highest in strong orange clawed males (6.351) and lowest in small males (2.814). Among the various biochemical components of male morphotypes studied, protein, RNA and DNA in muscle tissue as well as carbohydrate and RNA in hepatopancreas showed significant differences. Faster somatic growth observed in strong orange clawed males can be correlated with the higher values of protein, DNA and RNA recorded in the muscle tissue as well as high HSI, carbohydrate and RNA contents of hepatopancreas. The results of the present study reveal that there exists perceptible variations in HSI and biochemical profiles among the male morphotypes of M. rosenbergii.