Enzymatic fish protein hydrolysates in finfish aquaculture: a review

Abstract

In intensive farming systems, fish are held at high densities, which may increase stress, leading to susceptibility to diseases that result in economic losses. Therefore, effective feeding practices incorporating health-promoting compounds such as proteins, hydrolysates and bioactive peptides that can stimulate the defence mechanisms of fish and achieve better growth are some of the priorities for sustainable aquaculture development. Globally, the fish processing industries generate and discard a large volume of waste every year, estimated at up to 60% of the harvested biomass. This waste can be converted to value-added products such as fish protein hydrolysate (FPH) with the addition of various proteolytic enzymes. FPH from fish processing waste including skin, heads, muscle, viscera, liver and bones is a good source of protein, amino acids, peptides and antioxidants and has been found to possess desirable functional and bioactive peptides. A moderate inclusion of FPH in aquafeeds has the potential to improve growth, feed utilization, immune functions and disease resistance of fish. Production of FPH, targeted to more precise molecular weight ranges, has superior functionalities that are in high demand. With interest in FPH as an aquafeed supplement, this review aimed to summarize the source, production processes and functional properties of FPH and the reported impact of FPH in aquafeed supplement on fish growth, survival, feed utilization, immune response and disease resistance. Possible limitations of using FPH and future research potential as an opportunity for the use of processing fish waste are also discussed.

Digestive tract morphology and enzyme activities of juvenile diploid and triploid Atlantic salmon (Salmo salar) fed fishmeal-based diets with or without fish protein hydrolysates

“…On the other hand, high dietary levels of hydrolysed protein or high percentages of free AAs may modify the rate of AA absorption compared to absorption rates of amino acids present in polypeptides or intact proteins [ 37 ]. This could result in a decrease of feed efficiency linked to the imbalance between patterns of absorption between protein-bound and free AAs [ 38 , 82 ].…”

“…Hydrolysed fish protein (HFM) contains free amino acids (AAs) and small peptides that can stimulate the secretion of proteolytic enzymes and modulate their activity [29][30][31][32][33][34][35], and free AAs and peptides may also be absorbed more rapidly than the products of enzymatic breakdown of intact dietary proteins [36,37]. Biofunctional properties of HFM and their active compounds in promoting digestive activity, feed intake and effciency, and fish immunity [38] might have a positive effect on the growth (and survival) of triploid fish.…”

Use of fish hydrolysate in aquaculture: a review of some beneficial results in aquafeeds

“…Esta hidrólisis es más ventajosa que el método químico, porque permite un mayor control y selectividad del proceso, siendo menos drástico y generando un producto de mayor valor nutricional (Zamora-Sillero, 2018). El perfil peptídico del producto final está afectado por factores como: concentración de sustrato proteico, tipo de enzima, concentración de enzima (0,01% -5,0%), pH (1,5 -11,0), temperatura (35 -60 °C) y tiempo (10 -600 min), los cuales influyen en gran medida sobre la reacción cinética de las enzimas (Siddik et al, 2021). Generalmente, existe una combinación óptima de pH y temperatura en la que una enzima es más activa, y también una combinación en la que una enzima puede desactivarse mediante la desnaturalización (Zamora-Sillero, 2018).…”

Hydrolysis Methods for Protein Extraction from Seafood

“…Positive effects of ultrasound to proteases performance were observed and indicated by 61.76% of protein hydrolysis yield with rainbow trout substrate in Alcalase 2.4 enzyme [14]. Isopropanol and ethanol solvents and mechanical separations can be applied to remove of lipids and insoluble material in enzymatic hydrolysis that upgraded product quality [15]. Moreover, amino acids from seafood hydrolysis in presence of the catalysts could polymerize to di-, tri-or/and tetrapeptides, and then separated by precipitation [16].…”