Medicinal Plant Survey: ‘Good for Humans, Good for Fishes!’

Medicinal plants as dietary supplements and alternative therapeutics in fish and invertebrate aquaculture have been considered healthy and safe in many studies because plants are ‘natural’ and therefore considered harmless. This chapter provides information on a variety of plants as dietary supplements, mainly known as ethnopharmaceuticals. Typically, animals respond with improved immunity and accelerated growth performance; in many cases, both traits appear to respond independently. The importance of gut microbiota is beginning to be understood. Gut microbes can provide short-chain fatty acids from fiber and can promote beneficial and suppress harmful microorganisms. Occasionally, however, no beneficial effects at all are seen with dietary supplements of medicinal plants. Finally, the chapter points out examples of dietary supplementation with medicinal plants with only small distances between the beneficial dose and the toxic dose, suggesting careful observation of effects and toxicity evaluation prior to dietary supplementation.