Effect of different levels of earthworm (Eisenia fetida) meal on some of growth parameters and skin pigmentation in Oscar (Astronotus ocellatus) fry

Abstract

Introduction: This study aimed to investigate the effect of replacing a commercial feed with different ratios of earthworm meal (0 (Control), 5, 10, and 15%) on growth parameters and skin pigmentation in Oscar fry.
Materials & Methods: For this purpose, the experiment was performed in a completely randomized design with four treatments and three replicates. One hundred and twenty of Oscar fry with an initial average weight of 4.32±0.35g were dispersed into 12 aquaria. The stocking density was 10 fingerlings per aquarium. After 8 weeks, three fish from each treatment were randomly selected to measure the studied characteristics.
Result: The highest final weight (18.31±0.49 g), specific growth rate (2.51±0.11 %/day), survival rate (100 %), and the best food conversion ratio FCR (1.74±0.14) were observed in the fish fed with 5% earthworm meal compared to others (p<0.05). Total carotenoid at all treatments was significantly higher than the control group (p<0.05). The mean level of a* and b* factors in treatments replacing
with 5 and 10% of earthworm meal was significantly higher than the control group (p<0.05); While, L* factors in mentioned levels (5 and 10%) was significantly lower than the control group (p<0.05).
Conclusion: In conclusion, the results of this study showed that replacing the commercial feed with earthworm meal at 5% had positive effects on growth parameters and skin pigmentation factors in Oscar fry.