Bioactive peptides from seafood processing by-products affect growth performance, plasma biochemistry, gut health, and stress resistance of gilthead seabream (Sparus aurata)

The reutilization of salmon by-product to produce via enzymatic hydrolysis bioactive peptides (BPs) is a smart way to increase the sustainability and circularity of the aquaculture sector. In this context, the aim of this study is to evaluate the effects of administrating these BPs into the diets of gilthead seabream (Sparus aurata). Furthermore, the investigation explores potential advantages within the context of climate change, providing a comprehensive understanding of the diverse implications associated with this dietary approach. For these purposes, fish were treated with diets containing different BP levels (0% BP0, 5% BP5, 10% BP10) for 58-day trial period, then were exposed to suboptimal environmental conditions (high water temperature, low oxygen) for 7 days. Concerning the sea bream gut microbial community, BPs dietary treatments determined an overall increase in terms of the relative abundance of the most part of the host-associated bacteria compared to the control diet (BP0_T1), while rearrangements of the microbiota profile were observed in samples collected after the exposure to suboptimal rearing condition. Sea bream fed with diet supplemented of BPs seemed less responsive to stressing conditions, in terms of microbiome variations, compared to the control group (BP0), in which a relevant decrease in abundance was observed in several bacterial genera. Stenotrophomonas and Acinetobacter were the only genera increasing after suboptimal rearing conditions (T2) in all the three diets, and positively associated to hematic parameters like lactic and uric acids.