Effects of earthworm,Perionyx excavatusmeal in practical diets on growth and body composition of common carp,Cyprinus carpio
Invertebrates including poly- and oligochaete worms are often part of the natural diet of fish. Previous studies on the applicability of earth worm meal (EWM) as a protein source for fish have produced contradictory results. In this trial, we designed four isonitrogeneous practical diets (32% protein) containing 12% fishmeal with 0%, 30%, 70% and 100% of the fishmeal replaced by EWM (Perionyx excavatus). Other protein sources were soybean meal, rice bran and wheat meal while amino acids were supplemented where required. All diets were fed to common carp Cyprinus carpio of 11-12 g for eight weeks in 5 replicates to investigate the influence on growth and body composition of carp. Feed palatability was good and all diets were consumed at all times. Fish fed the fishmeal control diet grew significantly better than those fed diets containing EWM. There were no differences between the three EWM diets. Significantly higher protein efficiency ratio (PER) and protein productive value (PPV) were observed in fish fed the control diet. This suggested that a so far unknown factor in EWM impairs protein metabolism in carp independent of its concentration in the diet. Further research on processing of EWM is required in order to make full use of this bioresource.