EFFECT OF DRY FISH SUPPLEMENT IN THE DIET OF POLYCHAETE WORM (PERINEREIS NUNTIA)

Abstract

Polychaete worms, particularly Perinereis nuntia, are widely used as high-quality live and processed feed in shrimp hatchery and brood stock systems. However, sustainable production of polychaetes requires nutritionally balanced and cost-effective formulated diets. The present study evaluated the effects of graded levels of dry fish powder supplementation on the growth performance, survival, physiological condition, and nutritional quality of P. nuntia under controlled culture conditions. A 50-day (September, 2025 to November, 2025 ) feeding trial was conducted at Niribili Tilapia Hatchery, Cox’s Bazar, Bangladesh, using five dietary treatments (T0–T4) with increasing levels of fish powder inclusion. Growth performance was assessed through weight gain (WG), length gain (LG), specific growth rate (SGR), relative growth rate (RGR), average daily gain (ADG), and Fulton’s condition factor (K), along with survival rate and proximate composition analysis. Dietary treatments significantly affected all growth parameters (p < 0.001). Polychaetes fed T3 (7.5% fish powder) exhibited the highest overall growth performance, achieving a weight gain of 0.416 ± 0.094 g, length gain of 2.48 ± 0.13 cm, and the maximum SGR (2.151 ± 0.302 % day⁻¹), RGR (0.022 ± 0.003), and ADG (0.008 ± 0.002 g day⁻¹). Although T4 showed comparable length gain, it was associated with reduced survival. Fulton’s condition factor declined significantly with increasing dietary inclusion, decreasing from 0.693 ± 0.039 in the control to 0.432 ± 0.062 in T3, reflecting efficient energy allocation toward somatic growth rather than compromised health. Dose response analysis revealed linear increases in WG, SGR, and ADG with increasing fish powder levels, while LG displayed a significant quadratic response, with an estimated optimum at approximately 10.21% inclusion. However, considering growth efficiency, survival rate, and economic feasibility, 7.5% inclusion (T3) represented the most balanced and effective dietary level. Proximate analysis confirmed improved nutritional quality of experimental diets, with crude protein increasing from 40.08% in the control to 49.79% and crude fat 11.97% in the control to 13.76 in T3. The findings demonstrate that moderate inclusion of dry fish powder (7.5%) significantly enhances growth performance and feed efficiency of Perinereis nuntia while maintaining acceptable survival. This study highlights the strong potential of fish powder based diets to support sustainable polychaete culture, reduce dependence on wild-harvested polychaetes, and ensure a reliable supply of high-quality feed for aquaculture broodstock systems.