Growth performance of common catfish (Ameiurus melas Raf.) fingerlings fed insect meal diets

A growth trial was performed to evaluate the effect of replacement of fish meal (FM) with insect meal (IM) on growth performance and survival rate of common catfish (Ameiurus melas). Fingerlings of A. melas were randomly distributed into 4 indoor tanks of 2 m3 at a density of 2,000/tank (2 replicates), and kept at a temperature of 23-25°C in two separated recirculating aquaculture systems (RAS). Fish were divided in two groups: FM and IM, differing for the feed. Fish of the FM group were fed a control diet of 50% FM protein and 18% lipid whereas those of the IM group received the same diet but protein component consisted of 50% FM and 50% IM (Tenebrio molitor). Fish were fed with crumbled diets (200-500 μm) by means of automatic feeders (12 h) at a daily ratio of 6% (day 1- day 30), 5% (day 31- day 60), and 4% (day 61- day 90) of biomass. The trial lasted 90 days and fish weights were monitored at 30 days intervals. Growth performances were good in both groups. However, fish of the IM Group reached a final mean body weight (4.2±0.6 g) significantly lower than that of the FM one (5.13±0.7 g). The survival rate of FM group (79%) was higher than that of IM (70%), too. In conclusion, the results of this study demonstrated that the diet including insect meal was able to sustain growth in catfish fingerlings. Differences in the survival rate were significant between the two groups but the results can be considered fully satisfying. In fact, the survival rate of the IM group was more favourable if compared with the one obtained in first rearing ponds located at the catfish farm (30-50%).