Aquaculture nutrition in Australia: challenges and trends.

This review provides an outline of some of the challenges facing nutritionists in the Australian aquaculture industry. It commences with a brief description of how aquaculture nutrition differs from that for terrestrial livestock – the challenges of providing nutrition in aqueous environments, the diversity of species and the high trophic level of most. Specific challenges of aquaculture nutrition are then discussed in further detail, including the difficulty of measuring feed intake and digestibility, the limited ability to use carbohydrates for carnivores, and the specific requirements of species for lipids, including cholesterol, phospholipids, long-chain polyunsaturated fatty acids and carotenoids. The review then examines how environmental, social and governance concerns are leading to new trends in nutrition for the Australian industry. This includes topics such as the replacement of wild-caught fish meal and fish oil, in terms of both sources of omega-3 lipids and protein. For the former, possible solutions include greater use of seafood trimming, algal oil, and GMO-derived products. For the latter, solutions can include use of livestock render, plant protein meals, fermented products, and insects. Nutrient discharge is also a concern for the industry and nutritionist can assist by improving digestibility and nutrient retention from feeds. Finally, the carbon footprint of aquaculture is leading to new directions for industry and, in turn, for the field of aquaculture nutrition. Aquaculture feed formulations are being re-imagined. Not only do formulations have to meet the rigid nutrient requirements of the high trophic species cultured, but they will also have to adhere to increasing expectations of sustainable farming, animal health and welfare, and seafood quality. Environmental, social and governance concerns are steering the aquaculture industry in new directions and influencing nutrition research. This review provides an outline of some of the challenges facing nutritionists, which are leading to new trends for feeding Australian aquaculture. [ABSTRACT FROM AUTHOR]