Evaluation of earthworm meal (Eudrilus eugeniae) as fish meal replacement in juvenile Mangrove Crab (Scylla serrata) diet

Abstract

Two feeding trials were conducted to evaluate the performance of the earthworm (Eudrilus eugeniae) meal (vermimeal) as a replacement for fish meal in the diet of juvenile mangrove crab (Scylla serrata) in terms of growth, feed efficiency, intermolt duration, carapace width increment, molting success, survival, and incidence of cannibalism. Four experimental diets were formulated with 0, 25, 50, and 75% fish meal protein replaced with earthworm meal protein, designated as D0, D25, D50, and D75, respectively. In the first feeding trial, the experimental diets were fed to crablets with an initial average weight of 0.09±0.007g. Each replicate comprised ten (10) crablets individually stocked in 750ml-capacity plastic containers randomly distributed in a static water bath. Final weight gain, feed efficiency and survival were measured after the 5th molt. In the second feeding trial, 150 crablets with an average weight of 0.07±0.002g were stocked at 30 crablets each in five (5) replicate tanks. Survival and incidence of cannibalism were monitored daily until the end of the culture period of 30 days. The first study showed that the growth of mangrove crab juveniles fed the diet with up to 50% of the fish meal protein replaced by the earthworm meal protein was statistically comparable to the control group. The survival of crablets in the second feeding trial was highest in D25 (33%), followed by D50 (29%), D0 (18%), and lowest in the group fed with D75 (13%). Overall, earthworm meal (Eudrilus eugeniae) can replace as much as 50% of the fish meal protein in juvenile mangrove crab (Scylla serrata) diet without negative effects on growth, carapace width increment, feed efficiency, intermolt duration, molting success, survival, and cannibalism.