**6. Conclusion**

The highest maximum exploitation of marine resources used to produce FM has enforced fish nutritionist to use alternative protein sources as FM substitute in aquafeed. Worldwide availability and relatively cheaper price make SBM as one of the suitable alternative ingredients in aquafeed. However, high proportion of soy protein sources inclusion in aquafeed may impair fish immunity, maturation, and functionality of the intestinal mucosa, the first line of defense, and damage the gastrointestinal tract. However, using the appropriate proportions of alternative protein sources as well as SBM provides not only the option of limiting harm, but also there is also an interesting possibility to enhance GI immunity and disease resistance. From the available literature, it is showed that non-salmonids are less susceptible on the effects of SBM on the gut microbiota as well as the gut health than salmonids species. Until today, research on the effects of high soy protein inclusion in non-salmonid diets on gut health is little; so, more research warranted for non-salmonids fish. Future study is also needed on the use of different functional supplement in SBM-based diet to increase the efficiency of utilizing alternative protein (soy protein) through maintaining improved physiological and gut health condition. To date, most of the studies on SBM inclusion in aquafeed and its effects on fish intestinal microbiota were descriptive and only concerned the composition of the microbial community. Further works are warranted to investigate the functions of subpopulations in the microbiota and ultimately the functions to the species level due to alternative protein inclusion in aquafeed. In addition, the anaphylactic effects of SBM and the immune regulatory mechanisms involved merits further investigation.
