Dietary filamentous fungi (Neurospora intermedia) and duration of feeding modulates gut microbial composition in rainbow trout (Oncorhynchus mykiss)

Microbial proteins including filamentous fungal biomass contain noticeable levels of protein, fatty acids and other nutritious components. Also fungi cell wall contains chitin and chitosan and other polysaccharides as their bioactive components. The high nutritional value of Neurospora intermedia and its categorization as a dietary safe microorganism make it an ideal alternative ingredient for fish feed.The gut microbiota is critical to fish nutrition as it produces several enzymes which help in digestion, transport of nutrients, direct protection from pathogens, and enhanced immunity. Most of the studies have investigated the short- or long-term effect of diet on gut microbiota but, to our knowledge, none has investigated gradual changes in microbial communities over time. Moreover, the diets may not always has beneficial effect on fish physiology and digestion which can be perceived through gut microflora. It has also been shown that Arctic charr fed filamentous fungi (Rhizopus oryzae) display higher frequency of diarrhea, despite high apparent digestibility coefficient.Therefore, understanding the interaction between host, gut microbiota, diet, and feeding strategy is important when developing novel diets, in order to ensure better fish health and welfare. The primary aim of the project is to extend this knowledge by examining the role of novel filamentous fungi in modulating the intestinal microbiota of rainbow trout over successive 10-day feeding intervals. Secondary aim is to interpolate its efficiency as a fish feed ingredient.