Aquaculture is one of the fastest-growing food industries globally. According to FAO 2024, the world aquaculture production in 2022 achieved a new record of 130.9 million tons (94.4 million tons of aquatic animals), a 6.6% growth from 2020. This increase was mainly from finfish aquaculture production. However, aquaculture production has increasing challenges, including disease mitigation and feed costs. As this industry grows, finding sustainable alternatives to traditional fishmeal (FM) in fish diets has become a key focus. This work summarizes the findings of our three published growth studies that evaluated the potential of insect and clam meals as alternatives to FM in finfish diets using growth performance, physio-biochemical, and molecular approaches.
Insect meal studies: For the first study, a 12-week growth trial was conducted to evaluate the effects of FM substitution by defatted mealworm meal (50% and 100%DMM) and whole mealworm meal (50%WMM) in the diets of Atlantic salmon parr. The study found: (i) statistically similar growth performance between treatments; (ii) dietary DMM significantly increased plasma immunoglobulin M and up-regulated the expression of immune genes compared to the control diet (FM-based diet); and (iii) mealworm inclusion significantly changed gut microbial beta-diversity and the most common genus in all treatments was Pseudomonas. In a second recently conducted growth study (factorial design), Atlantic salmon parrs were fed with a control diet (FM diet) and six test diets [three levels of defatted black soldier fly larvae (DBSFL) meal and two soy protein levels] for 12 weeks. The study suggested that DBSFL meal, up to 15% of the diet, could replace FM without compromising Atlantic salmon growth and health; and alleviate inflammation caused by anti-nutritional factors derived from soy proteins.
Clam meal study: A 12-week feeding trial was conducted to assess the effects of FM replacement by clam meal (10%, 20%, and 30%CM of the diet) in the diets of Florida pompano juveniles. The study found: (i) significantly higher final weight in fish fed 10% and 20%CM diets than those fed the control diet; (ii) no significant difference in plasma health parameters; (iii) similar gut microbial diversity between the treatments; and (iv) the most dominant genera across all treatments was Vibrio, which could produce hydrolytic enzymes such as amylase, lipase, cellulase, and chitinase, that assist fish to breakdown dietary components.
Overall, these studies suggest that both insect and clam meals offer promising, sustainable alternatives to traditional fishmeal in aquaculture diets. Not only do they support finfish growth and health but also positively influence immune responses and gut microbiome, highlighting their potential to help meet the growing demand for sustainable aquafeeds.