Study of the Substitution of Marine Animal Oils in Maggot Flour by Vegetable Oils for the Growth and Larval Survival of African Catfish, Heterobranchus longifilis Valencienne, 1840 in Aquarium

This study showed clearly the effect of adding palm oil to the diet of farmed fish to replace marine animal oils. For this purpose, four foods based on maggot flour at 35% protein with the incorporation of palm oil, at different levels at 0, 2, 5 and 10% were tested in the to assess their impact on the improved growth performance, food utilization, survival rate and biochemical composition of Heterobranchus longifilis larvae

Four experimental diets were formulated based on the maggot meal as the main protein source. These diets were formulated at 35 % protein levels with maggot meal and maize flour as the major ingredients containing different concentrations of palm oil levels at 0, 2, 5, and 10 %. This study was carried out in the reproduction laboratory, at Oceanological Research Center, Abidjan, Côte d’Ivoire, between the periods of September to November 2022.

The diets were offered to the larvae (average initial weight 0.004 ± 0.001 g) three times a day ad libitum for 49 days. At the end of rearing, the results showed that the different experimental foods distributed did not influence the quality of the rearing environment.

The best growth was obtained with the larvae subjected to diet containing 2% palm oil with a final average weight of 3.21 g and a conversion index of 1.63. Beyond this rate, larval growth decreases. Survival rates vary from 70 to 73 %. The conversion ratios are not significantly different and ranged between 1.63 and 2.3. On the biochemical larvae submitted to diet containing 10 % of palm oil had body lipid content (2 %) and high ash rich. As against a gain of protein is observed with larvae submitted to diets containing 2 % palm oil reflects an effect of protein.

From the present results, diet containing 2 % crude palm oil is considered optimal for Heterobranchus longifilis larvae.