ISSUE FOCUS 24 FEED & ADDITIVE MAGAZINE September 2022 where seaweed inclusion increased the relative abundance of beneficial bacteria such as Firmicutes and Bacillaceae, while decreasing pathogenic bacteria such as Gammaproteobacteria and Vibrionaceae. Niu et al., (2019) also conducted a white spot syndrome virus challenge trial, where mortality was reportedly lower in shrimp consuming seaweed-containing diets. Given the bioactive properties of several seaweed components, which offer opportunities to improve aquatic feed properties and other functional benefits including immune stimulatory and antioxidative effects, seaweed represents a very attractive value-enhancing ingredient for aquaculture. The key question is whether these effects lead to improvements in performance. A recent study demonstrated that including seaweed meal in diets for Atlantic salmon improved protein efficiency ratio and feed conversion ratio (Kamunde et al., 2019). In another study with shrimp, the inclusion of Ulva lactuca seaweed meal in the diet resulted in improvements in growth and FCR as well as enhanced lipid and carotenoid content of the shrimp (Elizondo-Gonzalez et al., 2018). Additionally, sulphated polysaccharides (SP) extracted from Ulva intestinalis and Gracilaria persica were fed to rainbow trout for 8 weeks. The fish receiving the SP had significantly improved growth rates compared to control fish (Safavi et al., 2019), demonstrating that using the extracted SP provided similar benefits as seen with whole seaweed meal in other studies. Taken together, the results of the studies cited provide substantial evidence that seaweed fibre delivers prebiotic benefits in aquaculture through improved gut health, leading to higher productivity. About Dr Jason Sands Jason is Head of Nutrition at Ocean Harvest Technology Ltd. In this role Jason is responsible for leading research to develop technical documentation, strengthen the OceanFeed brand and support OHT’s sales and distribution teams by providing technical guidance for the OceanFeed range of products. Prior to Joining OHT, Jason worked various research and technical roles with public, academic and private companies. Jason holds a Bachelor and Master of science degrees in Animal Science from Tuskegee University and The University of Tennessee, respectively, and a PhD in Animal Nutrition from Purdue University.
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