Ipinmoroti, M. O., Akanmu, O. A., & Iyiola, A. O. (2018). Utilisation of house fly maggots (Musca domestica) as replacement for fish meal in the diets of Clarias gariepinus juveniles. Journal of Insects as Food and Feed, 1-8.
Ipinmoroti et al. wrote:ABSTRACT
Fish meal is widely used in commercial feed production because of its amino acids profile, and high protein content, however, its usage constitutes a major cost in fish feed production. It is therefore essential to source for a highly nutritious, cheap and readily available substitute which can supply the farmed fish with necessary dietary requirements for proper growth and development. The study utilised house fly maggots (Musca domestica) cultured from poultry waste at varying inclusion levels of 0 (no inclusion), 25, 50, 75 and 100% (maggot inclusions) to replace fish meal in the diets and replicated thrice. A total of 180
juveniles catfish with initial average weight of 10.11±0.12 g were stocked at 12 fish per tank, acclimatised for 2 weeks and fed twice daily at 3% body weight for a period of 12 weeks. The proximate composition of wet maggots showed the presence of favourable amino acids similar to fish meal but had lower crude protein content (47.45%) with high ether extract (22.23%) and moisture content (83.52%). The water quality parameters such as ammonia, temperature and dissolved oxygen were monitored daily and showed no significant difference (P<0.05) among the treatments and were tolerable for fish culture. Sampling of fish was done weekly, the growth and nutrient utilisation, economic indices and haematological studies were done and analysis of variance was used for the statistical analysis. It was observed that 75% inclusion of wet maggot gave better results and rapid utilisation and conversion of feed to flesh and was evident in the weight gain (50.71 g), lowest feed conversion ratio (1.04±0.04), highest specific growth rate (1.99±0.00 g/day) and cheap in terms of cost of production (₦ 172.12). This shows that 75% of wet maggots can be recommended as an inclusion level in commercial fish feed for adequate utilisation by C. gariepinus juveniles.
I think the meal can be 75 percent maggot, and therefore only 25 % fish
Assuming maggots are very easy to breed, this could lead to a significant less costly fodder, but also, due to the fact fish meal is made from fish, collected in sea, to less need of these fishes.
This in its turn might result in more abundant prey for other fishes such as cot, which is a very popular fish (to eat)
Insect meals are becoming increasingly popular in fish foods. Several brands are already marketing black soldier fly larvae formulas or researching it now that it is AAFCO approved.
It does have some issues though.
The Omega 3 to Omega 6 ratio is not the same as fish meal. It is also low in methionine. It can be used to partially offset fish meal. But other marine proteins and oils are necessary to balance out the diet.
Cost is also a factor. It's a super premium ingredient and very expensive. But this is probably due more to limited supply and the cost could come down as more production facilities come online.
I know at least one production facility is using inedible food as the feed for the flies. They basically take spoiled and expired food from grocery stores and feed it to the fly larvae.
Apparently it's a very low cost feed source and readily available in some areas.
