Important antinutrients in plant feedstuffs for aquaculture: an update on recent findings regarding responses in salmonids

This review presents an overview of antinutritive factors (ANFs) relevant for fish nutrition. The sources of ANFs and the possibilities of reducing the impact of ANFs are briefly mentioned. Proteinase inhibitors, lectins, saponins and oligosaccharides are given a more thorough presentation regarding mechanisms of action and the state of knowledge regarding effects on gut function in fish and upper safe dietary levels. Thereafter, selected results from recent works addressing the involvement of T cells and proteinase-activated receptors in soybean-induced enteritis are summarized. Our conclusions are as follows: we are only beginning to understand effects of ANFs in fish; strengthening of the knowledge base is urgently needed to understand the effects and to find the means to overcome or modify these effects; interactions between the effects of ANFs appear to be very important; the microbiota may modify the effects of ANFs; not only salmonids are affected; not only soybeans contain ANFs of biological importance in fish; and with increased knowledge, we can develop better diets for optimal nutrition, health and economy in aquaculture.