The demand for sustainable aquaculture feeds continues to grow. In turn, there has been an increased need for alternative ingredient sources. In recent years, supply shortages and unstable markets of traditional commodities and marine proteins, like fish meal, have resulted in their limited use in next generation aquafeeds. This has resulted in a collective effort to solve the major challenge of identifying alternative protein sources that still retain the physical, sensory, and nutritional attributes of traditional feed stocks. Plant-based proteins have emerged as promising alternatives, generally offering a respectable protein content, balanced amino acid profile, and stable supply. However, plant-based proteins also offer many challenges such as added anti-nutritional factors, palatability concerns, and reduced nutrient digestibility.
One mechanism with the potential to positively transform plant-based proteins for aquaculture is fermentation. The viability of precision fermentation to enhance major nutrient components (proteins, lipids, and carbohydrates) is becoming more attractive to the aquaculture industry. Fermentation increases nutrient availability through improved digestibility while also reducing anti-nutritional factors. It also has the potential to produce bioactive compounds that offer added health benefits to several aquaculture species. The benefits include antioxidant, anti-inflammatory, and immune-boosting properties that can improve fish health and disease resistance. Additionally, fermentation creates pre-biotics and probiotics, enhancing the gut microbiome leading to better growth rates and digestibility.
We conducted a series of studies to evaluate the performance of fermented plant protein at various inclusions in aquafeeds with the objective of lessening the dependence on marine and land animal protein sources. Exploring the hypothesis, we analyzed the histology, digestibility, and growth performance of several commercially important freshwater and marine fish species including rainbow trout, coho salmon, Atlantic salmon, and European seabass. Results have shown that fermentation may improve the acceptance and nutrient utilization of plant-based proteins, notably soy, in the diets of carnivorous fish. Improved feed conversion ratios, specific growth rates, and apparent digestibility coefficients have displayed promising results in these 12-week studies that were conducted in recirculating aquaculture systems. We will also highlight a novel precision fermentation platform in which multiple plant-based feedstocks can be transformed to improve the health and growth performance of a variety of cultured fish species. The concluding outcome from the platform and these studies is that fermented plant protein can be successfully added at inclusions of 12 – 15% in the diets of carnivorous fish, improving growth while creating sustainable solutions for next generation aquafeeds