Arising from the circular marine by-product economy, these hydrolysates are regarded as highly effective functional ingredients that can successfully support the reduction of fishmeal in commercial diets and maintain growth performance comparable to high fishmeal diets and significantly improve gut health, non-specific immunity and disease resistance.
Protein hydrolysates, derived from the enzymatic hydrolysis of marine byproducts, are well regarded as high-value functional ingredients in aquaculture. These ingredients provide a complex profile of small peptides and free amino acids that offer multi-dimensional benefits:
- Nutritional and growth: high bioavailability and solubility of peptides enhance nutrient absorption and protein synthesis, leading to improved feed efficiency and growth.
- Functional and immunomodulatory: bioactive peptides exhibit potent antioxidant, antimicrobial and immune-stimulating properties, which are critical for host defence in intensive culture systems.
- Environmental and circular economy: utilising fish and shrimp processing residues reduces waste and promotes resource efficiency, aligning with the sustainability goals of the global aquaculture industry.
The objective of this research was to evaluate the efficacy of three types of marine hydrolysates manufactured by Aquaproducts in Vietnam, as fishmeal (FM) replacements in red seabream (Pagrus major) diets in terms of impact on growth, immunity, gut health and pathogen resistance. Peptitom a shrimp protein hydrolysate, Peptisalm, a salmon viscera hydrolysate and Peptimar, a marine fish hydrolysate from canning side streams are marine based functional protein hydrolysates positioned for aqua, livestock and pet food applications.
This collaborative research effort was conducted by Jeju National University and Aquaproducts, combining academic expertise and industry innovation in marine bioactive ingredients.
Dietary formulations
This study utilised a 10-week feeding trial with 576 juvenile red seabreams (initial weight, 41.10±0.16g). There were 6 experimental groups and 3 replicates for each group. The trial compared a high fishmeal (HFM) control against a low fishmeal (LFM) control and four experimental diets where fishmeal was further reduced and supplemented with hydrolysates. All diets were formulated to be isonitrogenous with 49.8% crude protein (CP) and isolipidic at 13.1% crude lipid (CL). Experimental diets (LPT5, LPT10, LPS10, LPM10 as shown in Table 1, utilisedutilized a base of only 100g/kg fishmeal. The marine hydrolysate in diet LPT5 partially replaced 50% of the fishmeal component while in diets LPT10, LPS10, LPM10, marine hydrolysates replaced all the fishmeal.
Post-trial, fish were subjected to bacteria Edwardsiella tarda challenge at a concentration of 1.2×108 CFU/mL) via intraperitoneal injection to evaluate survival over 10 days.
Growth performance and feed utilization
The trial demonstrated that the shrimp protein hydrolysate (Peptitom) supplementation effectively recovered the growth loss associated with fishmeal reduction. The LPT10 group with marine fish hydrolysates achieved growth performance statistically comparable to the HFM positive control in final body weight (FBW) and weight gain (WG), significantly outperforming the LFM group.
Fish in group LPT10 recorded the best FCR (1.20), indicating superior metabolic efficiency in converting dietary protein into body mass.
An outcome of the circular marine by-products economy. PEPTITOM a shrimp protein hydrolysate, PEPTISALM, a salmon hydrolysate and PEPTIMAR, a marine fish hydrolysate are marine based functional protein hydrolysates positioned for aqua, livestock, and pet food applications.
Innate immune response and antioxidant capacity
Dietary hydrolysates significantly bolstered non-specific immune defences. The LPT10 group emerged as the top performer across key markers.
- Lysozyme activity: LPT10 achieved the highest recorded value (0.77µg/mL), a marked improvement over the LFM group (0.50µg/mL).
- Myeloperoxidase (MPO) activity: LPT10 showed a significant increase (1.87) compared to LFM (1.40) and LPS10 (1.57), suggesting enhanced phagocytic cell function.
- Superoxide dismutase (SOD): LPT10 (79.9%) was statistically equivalent to HFM (79.0%) and significantly higher than LFM (70.8%), indicating a superior capacity to neutralise oxidative stress.