Novel bioactive peptides for aquafeed - A breakthrough in standardizing feed palatability independent of the quality of other raw materials
Nagireddy G, Grin, Rahul, Siok Thing Tan and Rajalekshmi M
In intensive farming systems, shrimp are held at high stocking densities, which may increase stress, leading to increased susceptibility to diseases that results in economic losses. Therefore, sustainable aquaculture requires incorporating functional feeds that can stimulate the defense mechanism, support health and improve growth performance. Functional protein hydrolysates containing bioactive compounds can be considered as better modulator for profitable shrimp production. A moderate inclusion of Shrimp Protein Hydrolysate in aquafeeds has the potential to improve palatability, growth, feed utilization, immune function and disease resistance of shrimp.
Introduction
Shrimp are "slow" and selective feeders with highly developed chemosensory system and low visibility. Hence, several attractants and feeding stimulants are frequently incorporated into shrimp feed to make them easier to identify, improve palatability, resulting in an increased rate of consumption. Due to its critical role in feed, which can encourage feed intake and boost growth performance, farmers prioritize palatability while feeding.
Better utilization of shrimp waste as palatants not only improves palatability, but also can able to recover valuable essential nutrients and bioactive compounds in byproducts. A good palatant will reduce the contact time of feed in water which reduces nutrient loss. However, using these products, particularly when included at higher levels or from low-grade fisheries, can affect the nutritional quality of the feed (potentially high levels of oxidation products and biogenic amines) resulting in poor performance. Hence, stringent quality criteria in utilization of these byproducts and production of protein hydrolysate is required. Utilization of shrimp protein hydrolysate containing bioactive peptides as a potential functional feed can boost the immune system, enhance palatability, feed intake and nutrient quality, thereby resulting in better growth performance.
A Novel Bioactive Peptide for Aquafeed
Kemin AquaScience has introduced a novel product (Proprevia™ N 100 LQ) made from shrimp protein hydrolysate through enzymatic hydrolysis, having excellent physico-chemical properties including increased solubility, water binding capacity and fat binding capacity. Proprevia™ N 100 LQ is characterized by high level of free amino acids and specific peptides, proven to boost the palatability of shrimp feed, which in turn increases nutrient uptake, resulting in improved performance. Pathogens are inactivated by heat treatment, thereby complying to the BAP guideline to feed shrimp by Proprevia™ N 100 LQ. Compared to typical fish hydrolysate, Proprevia™ N 100 LQ contributes higher essential amino acids and higher lysine content (Fig.1). Lysine, the first limiting amino acid, is known to produce maximum feeding response and feed ingestion of shrimp (Chutima, 2014). The amino acid profile of Proprevia N100 LQ is presented in Figure 1.
Bioactive Peptides from Proprevia
Molecular weight of peptides is considered to have a significant effect on biological activities of Proprevia (Figure 2). Low molecular weight peptides are more easily absorbed and assimilated by shrimp than those with higher molecular weight.
Role of Proprevia™ N 100 LQ in Shrimp Production
Biofunctional properties of Proprevia™ N 100 LQ and its active compounds facilitates better feed intake. Performance of Proprevia™ N 100 LQ is assessed in Litopenaeus vannamei, which shows improvement in survival rate, specific growth rate and FCR (Feed Conversion Ratio) as shown in Figure (3). Survival rate of Litopenaeus vannamei was improved by 19.6% when shrimp fed with Proprevia™ N 100 LQ. In addition, the FCR was also enhanced by 16.3% in treated group when compared to control group. The specific growth rate was elevated from 15.41 (% per day) to 15.66 (% per day).
Stimulation of Shrimp Feeding
To demonstrate the palatability effects of Proprevia, a study on improving the attractability and intake of feed in Litopenaeus vannamei was carried out with on-top application of 2% Proprevia. The time taken to start feeding with 2% coated feed in comparison to control is given in Figure 4. Time to start feeding on 2% coated feed was lesser than control. This is suggestive of attractability and palatability of Proprevia.
The comparison of feed intake for 2% Proprevia coating against control feed is shown in Figure 5. Coating of 2% Proprevia significantly improved the feed intake when compared to control feed. The increase in feed intake was 34% higher in feed coated with 2% Proprevia. The enzymatic hydrolysis during production of Proprevia causes formation of peptides with small molecular weight that act as attractants for shrimp. Feed palatability is often connected with the availability of small molecular weight peptides and free amino acids in hydrolysed proteins, which stimulate feed intake of shrimp. This in turn leads to improved feed utilization, including feed efficiency, protein efficiency and protein retention in shrimp. Increased survival rate was observed when Proprevia was added to the feed. This might be attributed to improved feed satisfaction, thus reduced cannibalism.
Conclusion
Palatants play a key role in feed intake of shrimp. Proprevia can improve performance in shrimp by stimulation of chemo sensory mechanism when they are fed even at low level of animal protein sources under sub-optimal farming conditions. The scarcity of key marine ingredients acts as a catalyst for the development of alternative ingredients that add more value to the shrimp production. PropreviaTM N 100 LQ gives formulators more flexibility by allowing them to use alternate protein sources regardless of the quality of other raw materials. Furthermore, less nutrient waste is generated and nutrient leaching in water is reduced by lowering the time necessary for shrimp on feeding, hence minimising pond eutrophication.
In conclusion, the growth performance and feed utilization of L. vannamei can be effectively improved by supplementing the diet with Proprevia™ N 100 LQ.
Learn more about Proprevia™ :
www.kemin.com/in/en/markets/aquaculture/products/proprevia
