Effect of graded levels of dietary ascorbic acid on the metabolic and redox modulation of intensively reared juvenile pikeperch (Sander lucioperca)

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This study investigates the impact of varying dietary ascorbic acid (AA) levels on the metabolic and redox responses of intensively reared juvenile pikeperch (Sander lucioperca). Over 112 days in a recirculating aquaculture system, fish were fed diets with AA concentrations ranging from 0 to 2000 mg kg−1. While growth performance and survival remained stable across treatments, higher AA levels induced significant metabolic changes, including alterations in oxidative stress markers.

Effect of graded levels of dietary ascorbic acid on the metabolic and redox modulation of intensively reared juvenile pikeperch (Sander lucioperca)

The article delves into the nuanced impact of dietary ascorbic acid levels on juvenile pikeperch reared under intensive aquaculture conditions. By systematically varying the amount of ascorbic acid in their feed, researchers uncovered how these levels influence both growth metrics and physiological health. What stands out is the discovery that while no additional growth was achieved by exceeding the baseline levels, the intake of ascorbic acid sparked measurable changes in metabolic activity and redox balance. The study highlights the importance of understanding these subtle shifts, especially as the industry pushes for more efficient and sustainable aquaculture practices.

The findings also emphasize the role of ascorbic acid in modulating oxidative stress, revealing that higher concentrations led to notable increases in antioxidant enzyme activities such as superoxide dismutase and catalase. These changes suggest that the fish were actively responding to the elevated oxidative load, a critical adaptation in environments where stress is prevalent. However, it’s important to note that these physiological adjustments, while beneficial in reducing damage, did not translate into improved performance in growth or survival rates when compared to standard diets. This underscores a key takeaway: the benefits of high-dose ascorbic acid may be context-dependent, revealing that not all gains come without trade-offs.

What makes this research particularly relevant is its direct implications for aquaculture managers. The data point to a scenario where feeding strategies must be fine-tuned—not just for maximizing output, but for maintaining balance in metabolic health. This balance is crucial for long-term sustainability, as it aligns scientific insight with practical application. As we look ahead, it becomes clear that continued exploration of such biochemical dynamics will be essential in shaping the future of fish farming. The study serves as a reminder that behind every number lie complex interactions between nutrition, physiology, and environment, warranting careful consideration in every decision.

This study evaluated the effects of graded dietary ascorbic acid (AA) supplementation on growth performance and physiological parameters of intensively cultured pikeperch (Sander lucioperca). Fish were fed diets containing 0 (G0), 27 ± 1.8 (G30), 108 ± 11.4 (G100), 311 ± 11.6 (G300), 809 ± 40.8 (G800), and 1963 ± 33.1 (G2000) mg AA.kg−1 of feed for 112 days in a recirculating aquaculture system (RAS). Each treatment was conducted in triplicate with 150 juveniles per tank (initial body weight 37.9 ± 7.91g). Growth performance, feed utilization, survival (>97.8%), and organosomatic indices did not differ among tested treatments. Blood biochemical analysis revealed modulation of selected metabolic parameters, including reduced LIP activity and elevated TG at higher dietary AA levels, while the indicators of hepatic integrity (ALT, AST, HSI) remained unchanged. Tissue AA concentrations increased dose-dependently in both liver and muscle, confirming effective dietary incorporation and bioavailability. Two highest dietary AA levels (800–2000 mg kg−1) significantly altered oxidative-stress markers as follow: SOD and CAT activities in mucus increased, whereas TBARS increased in both mucus and blood, accompanied by elevated GSH and GST in blood. This pattern indicates activation of compensatory antioxidant mechanisms in response to increased oxidative load rather than improved oxidative stability. Under standard RAS rearing conditions, increasing dietary AA beyond basal levels did not enhance growth or overall physiological performance in juvenile pikeperch but induced redox and metabolic modulation at higher inclusion levels which is very important for future successful growth-out pikeperch intensive culture. The present study indicates that increasing dietary ascorbic acid at higher inclusion levels 800–2000 mg kg−1 does not enhance growth and survival of juvenile pikeperch under intensive conditions but induces measurable metabolic and redox modulation. Dose-dependent tissue accumulation confirms effective incorporation of AA, while associated changes in oxidative-stress markers suggest adaptive physiological responses rather than improved functional status. These findings help refine understanding of AA-related redox regulation in pikeperch and indicate that supplementation beyond basal requirements may not provide additional production benefits under standard rearing conditions.

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