Polyphenols are plant-derived compounds with known biological activities and potential health benefits. Over the past decade, there are an increasing number of studies have investigated the application of polyphenols and polyphenol-rich additives in aquaculture as functional feed additives. There are several types of polyphenolic compounds such as flavonoids, phenolic acids, lignans, and stilbenes of widely known beneficial influences on the overall performances and immunity of fish, and thereby improving the health status and production of fish farms. This review discusses the beneficial applications, optimum recommended dose, and potential side effects of these natural compounds on the growth performance, proximate body composition, immune responses, disease resistance, reproductive performance, and fillet quality of different fish species. Also, it points out that the biological functions and mechanisms associated with the polyphenolic compounds involved in the pathways of antioxidant and pro-oxidant activities, as well as the modulation of gene expression and different immune parameters. The output of this review article provided overwhelming evidence to support the claim that natural polyphenols can be considered as relatively safe and viable alternatives to synthetic chemical compounds that not only to improve the fish health status but also to enhance the fish quality, productivity, and food safety while reducing the use of chemicals and antibiotics in the aquatic eco-systems.

The crucial need for safe and healthy aquatic animals obligates researchers in aquaculture to investigate alternative and beneficial additives. Medicinal herbals and their extracts are compromised with diverse effects on the performances of aquatic animals. These compounds can affect growth performance and stimulate the immune system when used in fish diet. In addition, the use of medicinal herbs and their extracts can reduce oxidative stress induced by several stressors during fish culture. Correspondingly, aquatic animals could gain increased resistance against infectious pathogens and environmental stressors. Nevertheless, the exact mode of action where these additives can affect aquatic animals’ performances is still not well documented. Understanding the mechanistic role of herbal supplements and their derivatives is a vital tool to develop further the strategies and application of these additives for feasible and sustainable aquaculture. Gene-related studies have clarified the detailed information on the herbal supplements’ mode of action when administered orally in aquafeed. Several review articles have presented the potential roles of medicinal herbs on the performances of aquatic animals. However, this review article discusses the outputs of studies conducted on aquatic animals fed dietary, medicinal herbs, focusing on the gene expression related to growth and immune performances. Furthermore, a particular focus is directed to the expected influence of herbal supplements on the reproduction of aquatic animals.