A study led by the fish functional genomics team at the Institute of Hydrobiology (IHB) of the Chinese Academy of Sciences, has revealed the potential of seabuckthorn and gallic acid in enhancing fish mucosal immunity and improving disease resistance. Published in Aquaculture, the study explores the effects of these plant-derived additives in combating foodborne enteritis and improving overall health in farmed fish.

Aquaculture plays a crucial role in providing a sustainable protein source to meet the world’s growing food demands. However, the high cost and limited supply of fishmeal have led to the increased use of plant proteins, such as soybean meal (SBM), in aquafeeds. While plant-based proteins are cost-effective, they can cause side effects such as foodborne enteritis and liver issues, particularly in carnivorous fish species. This leads to higher susceptibility to infectious diseases, reducing the health and survival rates of farmed fish.

In response to these challenges, the IHB team, led by Prof. XIA Xiaoqin and Associate Prof. WU Nan, conducted a study to investigate the effects of seabuckthorn and its core component, gallic acid, in preventing and treating soybean meal-induced enteritis (SBMIE) in grass carp. Their research builds upon previous studies in zebrafish, where seabuckthorn and gallic acid were shown to play significant protective roles in the gut-liver axis and mucosal immunity.

The research team conducted feeding experiments to measure the immunity and metabolism of the gut-liver axis. Results indicated that both seabuckthorn and gallic acid significantly enhanced the intestinal and liver immunity of grass carp, supporting mucosal health and preventing foodborne enteritis. These additives also improved the antimicrobial capacity of mucous membranes, which greatly increased survival rates in farmed fish.

When comparing seabuckthorn to gallic acid, the team found that seabuckthorn performed better in promoting lipid metabolism, controlling Aeromonas hydrophila infections, reducing inflammation, and increasing probiotic abundance. In contrast, gallic acid provided notable benefits in protecting the mucosal barrier and improving respiratory efficiency by increasing the gill filament space.

The researchers further compared the protective effects of seabuckthorn and gallic acid against Aeromonas hydrophila, a common fish pathogen. Both seabuckthorn and gallic acid significantly enhanced intestinal and liver immunity, supported mucosal health, and improved disease resistance. Their inclusion in fish feed led to higher survival rates, enhanced antimicrobial resistance, and better mucous membrane integrity.

The study determined that the optimal concentrations for both ingredients were 9.5 g/kg for seabuckthorn and 1.2 g/kg for gallic acid. Grass carp fed SBM-based diets with these additives showed improved immunity, mucosal health, and resistance to foodborne enteritis. Additionally, analysis of 16S rRNA gene sequencing revealed a reduction in pathogenic bacteria and an increase in beneficial microbiota, further supporting the gut-liver axis.

In conclusion, this study demonstrates the significant potential of seabuckthorn and gallic acid in enhancing fish mucosal immunity, promoting survival rates, and improving disease resistance in aquaculture. Seabuckthorn showed notable advantages in lipid metabolism and anti-inflammatory effects, while gallic acid excelled in maintaining mucosal barriers and improving respiratory efficiency. These findings highlight the promise of plant-derived additives as a sustainable and healthier alternative to fishmeal, offering a more resilient and eco-friendly approach to fish farming.

 (Editor: MA Yun)