40 SEPTEMBER 2015 • WORLD AQUACULTURE • WWW.WAS.ORG To sustain the apparent and needed growth in global aquaculture production of all species, economic, safe and reliable feed ingredients are among the most influencing factors. In addition, it is imperative that new technologies and formulation practices are developed to reduce the cost of feed needed to produce aquaculture species. A combination of marine and terrestrial sources of animal protein can be practical and costeffective as ingredients in aquafeeds (Tacon and Metian 2015). Rendered animal proteins and fats from processing terrestrial livestock are an important component of feed rations and are an integral part of feed manufacturing, playing an important and major role in the entire feed/food production cycle. Animal proteins are concentrated sources of protein and amino acids and have been a standard in feed rations for over 100 years in agriculturally advanced societies of the world. Fats and oils have been historically effective feed energy sources and have been used to increase the caloric density of rations. Animal by-products are well accepted these days as aquafeed ingredients because of short supplies and the escalating cost of fishmeal. The protein content of animal by-products is greater and the complement of indispensable amino acids is superior to those of plant origin. They are also less expensive than fishmeal. However, most single-animal by-products are unable to completely replace fishmeal. A combination of different animal by-products is more effective as the nutritional profile becomes more complete and balanced than any single by-product. Products based on this last aspect are referred to as “fish meal analogs” (FMA). A fishmeal analog may contain ingredients like blood meal, squid meal or squid liver powder, meat and bone meal, feather meal, poultry by-product meal, soy protein concentrates and crystalline amino acids, especially lysine and methionine. In addition, to ensure that a FMA and the artificial feed will be perceived as suitable food, it should leach a continual plume of attractants rich in free amino acids, especially taurine, glycine and other low molecular weight organic compounds such as nucleotides and nucleosides. Key immunoregulatory compounds and lowmolecular weight nitrogen compounds also can be added into the mix. These include lectins, biogenic amines, antioxidants, phenolic compounds, sterols and long-chain fatty acids. Feeding trials have been conducted to determine the amount of a concentrate or FMA that can replace fishmeal protein in several species, including trout, tilapia, catfish, grouper, cobia, tiger shrimp and white shrimp. Animal by-products have been extensively tested as partial replacement of fishmeal in feeds designed for shrimp (Cruz-Suárez et al. 2007, Hernández et al. 2008) but the quality and apparent digestibility values for shrimp of animal by-products of different origin have to be improved by the addition of protein of marine origin, such as squid meal or shrimp meals, which provide the balanced amino acid content required for shrimp (Hernández et al. 2011). Likewise, results show that weight gain and feed efficiency are slightly less in animals fed 100 percent FMA-based diets when compared to fishmeal-based diets. Most results indicate that FMA can substitute for fishmeal protein up to 80 percent. For example, poultry by-product meal mixed with hydrolyzed feather meal can replace 80 percent of the total protein in shrimp diets without growth retardation, and up to 80 percent of fishmeal protein in diets for several marine fish species has been replaced by a combination of meat and bone meal and blood meal (4:1) with no adverse effect on growth, survival, or feed efficiency. In a study conducted to evaluate the use of a FMA as a replacement for Peruvian fishmeal on the growth performance of tilapia Oreochromis niloticus, no significant differences were noted on the average weight gain and feed efficiency of tilapia fed a control diet (100 percent Peruvian fishmeal) and those tilapia fed a 50 or 100 percent FMA based diets (Mateo et al. 2001). Growth trials conducted to determine the effectiveness of substituting menhaden fishmeal with a FMA in practical diets for juvenile red drum, indicated that 50 percent replacement of the protein originating from fishmeal in the basal diet resulted in minimal changes in growth and feed consumption (Meilahn et al. 1996). On the other hand, for carnivorous fish species, aquaculture feeds usually contain a high level of fishmeal, as well as large amounts of phosphorus, which may be discharged into the environment as feces and urine. The use of FMAs can considerably improve the status of phosphorus in aquaculture feeds and low-cost diets with FMAs can be less polluting. Furthermore, the addition of specialty animal by-products, including protein hydrolysates and spray dried plasmas, to fishmeal analogs has resulted in performance gains in several aquaculture species. Products derived from pig intestines have been developed with more than adequate production and sanitary results, in most cases improving the palatability of feed. A high percentage of this protein source is in the form of peptides, which increase the digestibility of FMA products. Pig intestine peptides are a byproduct of heparin production, and therefore have high levels of control over quality and the production process. Feather hydrolysates produced by bacterial keratinases have also been used as additives in FMAs, and several species of bacteria with high keratinolytic activity has been isolated from feather meal broth. Moreover, pepsin digestibility and amino acid content of fermented feather meal (FFM) can be greatly improved over commercial feather meal. Microbial cells can also supply carotenoid pigments to FFM, suggesting that bacteria-enriched feather meal may be particularly useful in aquaculture feeding not just as a protein source but also as a pigment source. These products are beneficial in diets for early rearing of aquatic species for which fishmeal is presently considered indispensable. Perhaps the most rigorous test of a FMA-based aquaculture feed is its use Substitutes for Fishmeal and Fish Oil in Aquaculture Feeds Sergio F. Nates
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