Phytobiotics in finfish and shellfish: a systematic review

Aquaculture is an essential contributor to global food security, supplying high-quality protein through the farming of finfish and shellfish in both freshwater and marine environments. However, the intensification of aquaculture practices combined with inadequate water quality management has increased stress on cultured species, making them more vulnerable to infections from bacteria, viruses, and parasites. Traditional disease control methods, such as antibiotics and chemical treatments, pose significant risks including environmental pollution, antimicrobial resistance, and compromised food safety. Consequently, there is growing interest in exploring natural, sustainable alternatives like medicinal plant extracts and phytobiotics to enhance the health and resilience of aquaculture species. This systematic review compiles recent findings on the application of plant-derived bioactive compounds in diets of freshwater and marine finfish and shellfish. Rich in antioxidants, flavonoids, alkaloids, and essential oils, these phytobiotics exhibit immunostimulatory, antimicrobial, and antioxidant effects that bolster both innate and adaptive immunity while reducing oxidative damage. The evidence demonstrates notable improvements in growth performance, feed efficiency, immune response, hematological and biochemical markers, and disease resistance across species such as tilapia, catfish, sea bass, shrimp, and mussels. Integrating these plant extracts into aquafeeds presents a promising approach to reduce antibiotic dependence, enhance productivity, improve water quality, and support sustainable aquaculture development aligned with global environmental and food safety goals.