Evaluation of Alternative Dietary Ingredients as a Sustainable and Ecological Solution for Meagre (<i>Argyrosomus regius</i>) Production in Earthen Ponds

Abstract

The aquaculture sector is developing sustainability measures to address resource limitations and environmental concerns. A key strategy is replacing fishmeal and fish oil with alternatives that can equally sustain fish health, growth, and water quality. This study compared a standard diet (STD) to an alternative diet (ALT) containing sustainable ingredients, such as plant-based proteins and animal by-products, for meagre raised in earthen ponds within a polyculture system. Over 150 days, 5400 meagre juveniles (174.9 ± 32.8 g) were fed these diets. Fish on the ALT diet showed superior growth, likely due to higher dietary protein content and reduced protein degradation in liver and muscle, leading to increased protein content and reduced levels of dry matter, lipid, ash, energy, and phosphorous. While muscle cohesiveness was affected, fiber area and density were unchanged. ALT-fed fish exhibited higher saturated (SFA) and polyunsaturated (PUFA) fatty acids, reflecting the diet. Water quality indicators, including ammonia, nitrites, nitrates, and phosphates, were similar across diets, though chlorophyll a was higher in ponds with STD-fed fish. Overall, the ALT diet emerges as a sustainable alternative to the STD diet, maintaining or enhancing protein levels while reducing fishmeal usage. This approach effectively supports meagre growth and fillet quality without significant additional environmental impact.

Keywords

• fish nutrition
• sustainability
• environment
• plant-based ingredients
• animal by-products
• land-based aquaculture