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Fish hydrolysate, is a product distinct from fish meal and fish solubles, and has unique attractant applications. During the hydrolysis process, large protein molecules are enzymatically broken down to a range of smaller peptides and amino acids. These molecules have varying degrees of solubility so when added to aquaculture feeds, diffuse out of the feed at different rates giving a “phased release effect.” The modern hydrolysate concentration technology involves lower temperature vacuum evaporation process (60C) which helps to retain more of the beneficial functional and health properties of the fish protein. In trials shrimp feed palatability has been shown to be greatly enhanced with the hydrolysate application in both low and high fish meal feed formulations. Research has shown that excessive levels of fish hydrolysate, however, may impair performance. The optimum inclusion rate of fish hydrolysates for shrimp growth is about 3% dried fish hydrolysate (equivalent to 6% evaporated liquid hydrolysate). The Scottish salmon oil produced using the latest production technology attracts a premium over standard fish oils because the processing method produces oil with low odor and very low pollutant levels. Low levels of organic pollutants such as dioxins have been achieved by careful sourcing of fully traceable human grade salmon by-products. Micro-filtration is used to minimize even the small traces of pollutants. The oil is rich in mono- and polyunsaturated fatty acids. Since it is derived from salmon, it retains its carotenoid pigments (20 ppm) and astaxanthin (levels variable), which are natural oil antioxidants. To avoid the potential risk of disease transmission, the European Community has banned the feeding of the same fish species back to itself (intra-species ban). However, salmon products make an ideal protein source for shrimp. Likewise shrimp head hydrolysate is an ideal protein ingredient in salmon feed. So, there is yet more scope for two way byproduct utilization between the salmon and shrimp which will benefit both industries. The article has 2 tables and 3 figures. Full Paper
Useful References Provided by the Author Anggawati, A.M., Murtini, J.T., Heruwati, ES., (1992). The use of hydrolyzed protein concentrate in practical diets for Penaeus monodon juveniles. Research Report. Research Institute for Fish Technology. Palmerah Jakarta, p 12. Barlow, S. (2003). World market overview of fishmeal and fish oil. In: Advances in Seafood Byproducts Conference Proceedings, Bechtel P.J. (ed.) Alaska Sea Grant College Program, University of Alaska Fairbanks. p.11-26. Bechtel, P.J., Sakthivel, S., Oliveira, A.C.M., Smiley, S., and Babbitt, S. (2003). Properties of hydrolysates from pink salmon heads and viscera. Proceedings of the Trans Atlantic Fisheries Technology 2003 conference. Published by Icelandic fisheries Laboratory. p. 284-285. Córdova-Murueta JH. Garcia-Cerreno F (2002) Nutritive value of squid and hydrolyzed protein supplement in shrimp feed Aquaculture. 210: p371-384. Haard, N.F., (2001). Enzymie modification of food proteins. Chapter 7. In: Sikorski, Z. (Ed). The Chemical and Functional Properties of Food Proteins. Technomic Publishing, Lancaster, PA. Guillaume J (1997) Protein and amino acids, In: D’Abramo et al. (Eds), Crustacean Nutrition. World Aquaculture Society. NRC Nutrient Requirements of Dogs and Cats 2003 - National Research Council. In press. Lawrence, A.L. (2003) Shrimp Attractants, America 2003, WAS. Negret, E. (2003) The use of hydrolysed fish attractants in Aquaculture. World Aquaculture Conference, Brazil |
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Processing waste from aquaculture products is largely an untapped ingredient resource for the aqua feed industry. Oils and proteins recovered from the offal would partially offset the future gap in demand and supply of marine oils and proteins. This article reviews the opportunities for oil and hydrolysate manufactured from the processing waste of farmed salmon. Nearly 250,000 MT of waste is available for conversion into useful products such as salmon hydrolysate and oil. Since salmon is processed entirely for human consumption, very high standards of freshness and hygienic quality are followed. This can be used to advantage by the byproducts manufacturer to produce high quality byproducts. The processing wastes are stabilized within 4 hours of slaughter. The typical process of manufacturing salmon byproducts involves maceration of viscera or bony by-products and then enzymatically digesting the protein into a liquid soup. During the next stage bones are removed and the fish oil is separated by centrifugation. The final stage is concentration of the hydrolysate by either spray drying to produce a powder, or low temperature vacuum evaporation to produce a thick liquid. Yields of hydrolysate and oil vary with the type of fish processed. In Atlantic salmon, every metric ton of the byproduct yields about 200 kg each of orange coloured salmon oil and condensed salmon hydrolysate.
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