The effect of dietary L-carnitine supplementation on cold tolerance and growth of the ornamental cichlid fish Pelvicachromis pulcher - Preliminary results

The effect of dietary L-carnitine supplementation on cold tolerance, growth and survival of the ornamental cichlid Pelvicachromis pulcher was tested under laboratory conditions. Fish were reared for a period of 82 days on a diet containing different levels of added L-carnitine: 0, 500 (3.1 mmol), 1000 (6.2 mmol) and 2000 (12.4 mmol) mg/kg. At the end of the growth period the fish were exposed to a cold shock. Fish which received dietary L-carnitine supplementation (at all tested levels) exhibited significantly better survival rates following exposure to a cold shock, and readapted quicker to normal temperatures compared to the control group which had no L-carnitine added to their diet. The addition of L-carnitine to the diet at a level of 1000 mg/kg seems to yield the best protection against exposure to cold shock. Growth differences among the treated fish were not significant, although the fish which received 500 mg/kg supplementation exhibited slightly better growth.