Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Effect of dietary carbohydrate-to-lipid ratio on growth and body composition of walking catfish (Clarias batrachus).

Abstract

Isonitrogenous (40% CP) and isoenergetic (3.46 kcal/g, ME) semipurified diets with varying carbohydrate:lipid (CHO:L) ratios (0.02 to 43.00 (g:g)), were fed to triplicate groups of 12 walking catfish, C. batrachus, each in 70-litre flow-through (1-1.5 litres/min) indoor circular troughs. Fish were fed to satiation, 6 days a week, twice daily at 08.00 and 16.00 h. Over the 6-week study, growth rates in fish differed (P<0.05) with CHO:L ratio, producing a quadratic pattern. Total feed intake (mg/fish daily) was lower (P<0.05) in fish fed on diets containing low carbohydrate and high lipid. Maximum liveweight gain (160%), specific growth rate (2.3%), feed conversion ratio (1.24), protein efficiency ratio (2.02), protein retention (34%) and energy retention (42%) were observed in fish fed on a 27% carbohydrate and 8% lipid diet, corresponding to a CHO:L ratio of 3.38. Fish fed on the lowest (0.02) or highest (43.00) CHO:L ratio tended to produce lower (P<0.05) growth and feed conversion efficiency. Percentage of DM, whole body lipid and energy content (kcal/g) of fish increased (P<0.05) as CHO:L decreased. However, whole body CP and ash content of fish fed on varying CHO:L diets did not show any discernible differences among the test groups. The results indicate that walking catfish efficiently utilize carbohydrate for energy, and dietary lipid in excess, resulting in increased lipid deposition in the body.