The high cost of Aquaculture production in many parts of the world can be attributed among other factors to the high cost and scarcity of conventional feed ingredients which is competitively used by livestock industries and for human consumption. Fishmeal is one of such nutritionally high but expensive conventional feedstuffs, hence, emphasis of many nutritional studies has been to identify, alternative protein sources that are cheaper, less competitive, yet nutritionally comparable to this conventional feed ingredient. Toad meal is an example of such alternative, unconventional feed ingredients which lack competitive use probably due to the presence of toxin in its parotid gland and skin. However, its protein content and amino acid profile are comparable to many conventional protein sources (including fishmeal). In our earlier study, we successfully removed the sources of the toxin (parotid gland and skin) and established the nutritional characteristics of the processed toad, hence producing a safe Toad meal that could be incorporated in feed without fear of toxin poisoning. This study therefore, investigates the nutrient utilization of the skinned and deglanded toadmeal (SDTM) as a possible replacement for fishmeal in the diet of African catfish Clarias gariepinus.
Clarias gariepinus juveniles (9.24 ± 0.70g) were stocked in designated triplicate aquaria stationed at the indoor hatchery facility of the Department of Fisheries and Aquaculture, University of Agriculture, Makurdi, Nigeria. Toads were harvested and processed to remove the skin and the parotid glands before oven drying at 600C to a constant weight. The SDTM was used to replace fishmeal (at 0%, 25%, 50%, 75% and 100%) which was originally incorporated in the control diet at 30%. The fish were fed these experimental diets at 5% of the fish body weight for eight (8) weeks.
The results obtained suggest that SDTM can completely replace fishmeal without any adverse effect on growth or survival. Similarly, the carcass analysis also showed that 100% replacement of fishmeal with SDTM led to highest crude protein in the fed fish. Also, cost of production of feed and rearing the fish to market size (1kg) was substantially reduced as SDTM was substituted for fishmeal. It was therefore concluded, that SDTM can be incorporated in fish feed to completely replace conventional but expensive fishmeal.