Photo credit: Gerardo Ontiveros Lopez (Mexico)
Review: Abdel Rahman El Gamal (Founder of the website)
Introduction: The lumbricids which are commonly known as earthworms belong to the family Lumbricidae which hosts very many species that are naturalized around the world. Because earthworms could be used as fishing bait, it is also called “angleworm”, also, “night crawler” is among the common names of earthworms. In general, an earthworm is a tube-shaped, segmented animal that is commonly found living in soil, feeding on live and dead organic matter.
Nutritive merit of earthworms: Studies and analysis showed that earthworms contain on a dry basis about 65-70% protein with high essential amino acid content, especially lysine and methionine. They also have 6-8% lipid, 12-14% carbohydrate, in addition to minerals and several vitamins. The good nutritive merit of earthworms especially in regard to their high protein contents encouraged its use in several countries as a feed component or as the sole food of chickens, rabbits, and fish species.
Utilization of earthworms in aquaculture: Because of the steadily increase in the prices of fish meal that is required for fish formulated feed, earthworms have been searched –among others- as a possible replacement to fish meal whether in part or in full. Several research projects investigated the use and impact of the inclusion of earthworms on the productive performance of several fish species of different feeding habits including rainbow trout, tilapia, African catfish, Vundu, zig-zag eel, and others.
Research findings indicate the possibility of using earthworms either as live food for fish or as a partial replacement to fish meal in formulated feed. The 25% replacement of fish meal by earthworm meal has been recommended based on the outcomes of some research projects as well as economic justification. Interestingly to know in some countries the use of earthworms had better chances whereas there is an opposition towards the use of fish meal for the fear of its contamination with pork byproducts.