Flavonoids as functional food additives and their effect on immunity of Nile tilapia, Oreochromis niloticus

Authors: Aksoy, Mediha; OZDEMIR, YUNUS EMRE - Auburn University; AKSOY, JANSET - Auburn University; Beck, Benjamin

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/14/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Phytochemicals, especially flavonoids, are of great interest as functional feed additives due to their wide range of bioactive capabilities such as their antioxidant and antibacterial properties. Flavonoids are a group of more than 4,000 phenolic compounds that occur naturally in plants. They are categorized primarily into six classes, namely: flavanones, flavones, flavonols, isoflavonoids, anthocyanins, and flavans. Recent advances in immune-nutrition studies have revealed that some nutrients are linked to the immune status of fish. This study evaluates the effects of three different types of flavonoids (catechin, quercetin, and hesperidin) on growth, feed utilization, hematological parameters, immune responses, and resistance of Nile tilapia to bacterial challenges. Two dietary levels (0.1% and 1%) of each flavonoid and a control diet were offered twice daily to three replicate groups of Nile tilapia (initial weight 11.5g) for 8 weeks. Regardless of its level in the diet, hesperidin provided greater enhancement of serum complement activities, increased serum globulin levels, and significantly higher survival rates of fish against Streptococcus iniae challenge. However, high levels of both quercetin and catechin resulted in reduced weight gain. Quercetin was demonstrated as toxic to the liver and catechin reduced erythrocyte count and hematocrit. Low dietary levels of both quercetin and catechin failed to provide any health benefits. Thus, it appears that hesperidin can be used as functional feed additive in tilapia diet to enhance immunity to provide greater protection against pathogens with no side effects.