Utilization of the earthworm, Eudrilus eugeniae in the diet of Heteroclarias fingerlings

Abstract

The earthworm, Eudrilus eugeniae was cultured for 12 weeks and its meal utilized as a replacement for fish meal in the diet of fingerlings of the mud catfish hybrid (♂Heterobranchus longifilis X ♀Clarias gariepinus) called Heteroclarias. Two hundred and seventy adult E.eugeniae were cultured in three substrates: Soil, cellulose, or a mixture of cellulose and soil. The worms were harvested at the end of the culture period, processed by oven-drying and grounded into powdery form as earthworm meal. Cellulose substrate was the best for E.eugeniae culture with the highest weight gain and relative growth rate. The earthworm meal produced was used to replace commercial fish meal in five compounded diets at levels of 0 (control), 25, 50, 75 or 100%. The diets were fed to Heteroclarias fingerlings to evaluate the effect of earthworm meal in comparison with fish meal on the growth and nutrient utilization of the fingerlings. The feeding experiment was carried out in 40 L plastic tanks using 5 tanks per treatment and 15 fingerlings per tank, and the fingerlings were fed 5% of their body weight on a daily basis for 10 weeks. Highest mean weight gain was in fish fed 75% earthworm meal, while relative and specific growth rates were highest in fish fed 25% earthworm meal and lowest in fish fed the control diet. Food conversion ratio was lowest in fish fed 50% earthworm meal and highest in fish fed 100% earthworm meal. These results indicate that replacement of fish meal with earthworm meal at 50 to 75% inclusion level is suitable for optimal growth performance and nutrient utilization in Heteroclarias fingerlings. Key words: Eudrilus eugeniae, culture substrates, Heteroclarias, growth rate.