Synergistic Effects of Poultry Manure Extract and L-Carnitine on Growth and Mass Production of Moina macrocopa

Abstract

Background: Hatchery larviculture depends on live zooplankton, whose supply is limited by costly, inconsistent microalgal culture. Aims: This study aimed to develop and optimise a low-cost poultry manure extract (PME)-based culture medium for mass production of the cladoceran Moina macrocopa through dose optimisation and L-carnitine enrichment, and to compare its performance with a microalgal control and commercially available plankton-culture products. Study Design: Completely randomised design (CRD) with triplicate treatments across sequential bench-scale dose-optimisation trials and 50 L outdoor validation trials. Place and Duration of Study: Live feed and wet laboratories, ICAR–Central Institute of Fisheries Education (CIFE), Mumbai, India; experimental period of 60 days. Methodology: PME was formulated from poultry manure, fish waste, rice bran, groundnut cake, soybean meal, and single super phosphate. Seven PME concentrations (1–32 mL/100 mL) were evaluated using newly hatched M. macrocopa neonates, followed by testing six L-carnitine concentrations (0.001–100 mg/100 mL) with the optimal PME dose. The best-performing formulation was validated in 50 L outdoor cultures and compared with a Chlorella vulgaris control and four commercial media (Grow Plus, Nano Colostrum, Unique Liquid Media, and Plankton Booster). Population density, intrinsic rate of increase (r), doubling time, water quality, and PME composition were assessed. Results: The optimal PME concentration was 3 mL/100 mL, producing a peak density of 4.14 ± 0.32 ind mL⁻¹. Supplementation with 10 mg/100 mL L-carnitine (100 mg L⁻¹) increased density to 5.76 ± 0.26 ind mL⁻¹. In 50 L outdoor culture, PME enriched with 100 mg L⁻¹ L-carnitine achieved the highest density (9.85 ± 0.45 ind mL⁻¹), surpassing PME alone (7.09 ± 0.45 ind mL⁻¹), the C. vulgaris control (4.15 ± 0.27 ind mL⁻¹), and all commercial products. Grow Plus and Unique Liquid Media produced substantially lower densities, while Plankton Booster caused complete mortality. Conclusion: L-carnitine-enriched PME significantly improved M. macrocopa growth and productivity and offers a cost-effective alternative to conventional microalgal and commercial media for hatchery-scale zooplankton production.