Fish waste to sustainable additives: Fish protein hydrolysates alleviate intestinal dysbiosis and muscle atrophy induced by poultry by-product meal in Lates calcarifer juvenile

Abstract

Valorising waste from the processing of fishery and aquaculture products into functional additives, and subsequent use in aquafeed as supplements could be a novel approach to promoting sustainability in the aquaculture industry. The present study supplemented 10% of various fish protein hydrolysates (FPHs), obtained from the hydrolysis of kingfish (KH), carp (CH) and tuna (TH) waste, with 90% of poultry by-product meal (PBM) protein to replace fishmeal (FM) completely from the barramundi diet. At the end of the trial, intestinal mucosal barriers damage, quantified by villus area (VA), lamina propria area (LPA), LPA ratio, villus length (VL), villus width (VW), and neutral mucin (NM) in barramundi fed a PBM-based diet was repaired when PBM was supplemented with various FPHs (p < 0.05, 0.01, and 0.001). PBM-TH diet further improved these barrier functions in the intestine of fish (p < 0.05 and 0.001). Similarly, FPHs supplementation suppressed PBM-induced intestinal inflammation by controlling the expression of inflammatory cytokines (tnf-α and il-10; p < 0.05 and 0.001) and a mucin-relevant production gene (i-mucin c; p < 0.001). The 16S rRNA data showed that a PBM-based diet resulted in dysbiosis of intestinal bacteria, supported by a lower abundance of microbial diversity (p < 0.001) aligned with a prevalence of Photobacterium. PBM-FPHs restored intestine homeostasis by enhancing microbial diversity compared to those fed a PBM diet (p < 0.001). PBM-TH improved the diversity (p < 0.001) further by elevating the Firmicutes phylum and the Ruminococcus, Faecalibacterium, and Bacteroides genera. Muscle atrophy, evaluated by fiber density, hyperplasia and hypertrophy and associated genes (igf-1, myf5, and myog), occurred in barramundi fed PBM diet but was repaired after supplementation of FPHs with the PBM (p < 0.05, 0.01, and 0.001). Similarly, creatine kinase, calcium, phosphorous, and haptoglobin were impacted by PBM-based diet (p < 0.05) but were restored in barramundi fed FPHs supplemented diets (p < 0.05 and 0.01). Hence, using circular economy principles, functional FPHs could be recovered from the fish waste applied in aquafeed formulations and could prevent PBM-induced intestinal dysbiosis and muscular atrophy.GRAPHICAL ABSTRACT

Replacement of fishmeal with a microbial single‐cell protein induced enteropathy and poor growth outcomes in barramundi (Lates calcarifer) fry

“…A study with similar size barramundi (starting at 2.5 g) where FM was progressively replaced by varying proportions of alternative protein ingredients, including lupin kernel, black soldier fly meal and poultry by-product meal, also found a correlation between higher rates of FM substitution with the proliferation of opportunistic pathogens in the genus Aeromonas and Vibrio (Gupta et al, 2020). Similarly, an increase in Photobacteria, another opportunistic pathogen, was described for juvenile barramundi (starting at 7.25 g) fed poultry-by product meal, but functional feeds (e.g., fish protein hydrolysates) were able to alleviate intestinal dysbiosis (Chaklader et al, 2023).…”

Safety, Processing, and Utilization of Fishery Products

“…Fish protein hydrolysates restore gut microbial composition in farmed juvenile seabass fish, indicating improvements on aquafeed formulations. The anti-inflammatory effect imparted by fish proteins is noteworthy [141]. The anti-inflammatory feature gives a competitive marketing edge to fish protein hydrolysates over poultry hydrolysates.…”

Market-driven assessment of alternate aquafeed ingredients: seafood waste transformation as a case study

“…Compositional considerations such as proximate, amino acid and fatty acid composition and the presence of anti-nutritional compounds have been paramount. Studies have also reported on the health and immune status of the fed fish (such as histological, blood biochemistry and gut microbiome results; Chaklader et al 2021a;Jannathulla et al 2021;Alfiko et al 2022;Aragão et al 2022;Chaklader et al 2023a). Of equal importance is the consideration of operational/ supply parameters for the inclusion of novel ingredients, such as their consistency of quality, cost, transport logistics and scale of production or supply (Hua et al 2019).…”