Larval rearing of an African catfish,Heterobranchus longifilis, (Teleostei, Clariidae): a comparison between natural and artificial diet

Two feeding experiments were conducted to evaluate growth and survival rates of African catfish (Heterobranchus longifilis Valenciennes, 1840) larvae fed with different diets: live Artemia nauplii, frozen Artemia nauplii, live zooplankton (Moina micrura), frozen zooplankton (Moina micrura), a dry diet based on yeast powder and beef liver, and a commercial trout starter diet. The larvae were fed in excess, six times per day every 4 hours, from the onset of exogenous feeding up to an age of 14 days. In both experiments the final mean weight and specific growth rate of fish fed live Artemia nauplii were significantly higher than those of fish fed other diets (p > 0.05). Survival rates of fish fed Artemia (live or frozen), Moina micrura (live or frozen) and dry diet did not significantly differ (p > 0.05) and ranged from 79 to 92% and 61 to 73% for experiment 1 and experiment 2, respectively. The commercial trout diet led to significantly lower growth and survival rates in comparison to all other diets tested. Although it led to a lower growth rate than that obtained with Artemia, Moina micrura proved suitable for first feeding of H. longifilis larvae. Locally available in West African waters, this cladocera could constitute a valuable alternative for larval rearing when a shortage of Artemia is expenenced. The results also showed that the artificial feed based on yeast powder and beef liver leads to survival rates as high as those obtained with living diets and thus represents a promising way for feeding H. longifilis fry. However, further studies on the nutritional requirements of the larvae remain necessary in order to improve the efficiency of dry diet in terms of growth performance.