Undoubtedly, omega-3 fatty acids (DHA and EPA) have been a hot topic in nutrition science for decades and still stand as one of the most proven health supplements having multiple heath benefits for human body.
Omega-3 oils, which normally are produced from fish oil, are a commodity with high market needs for both human nutraceuticals industries and animal feed industries. Further, fishmeal and fish oil, which make up the bulk of the ingredients in diets for farmed carnivorous fish, are obtained from finite sources that are fully exploited or in some cases overfished. Though some marine fishes have the ability to synthesize omega-3 fatty acids, it has become a gold standard to supplement fish oil in the diets carnivorous fish species for increasing consumer acceptability of the final products due to its health benefits. All went fine, until the real sustainability issue came into the focus.
Between 1950 and 2003, the amount of fish and shellfish landed by capture fisheries destined for reduction into meals, oils and other nonfood purposes increased from 3 million tons to 21.4 million tons(1). Over-fishing of the world's oceans has depleted fish numbers severely, leading to a shortage of small fish such as anchovies, herring, and mackerel and in consequence, an imbalance in the marine ecosystem. As a result, governments all over the globe are taking drastic measures to help mitigate this problem. Beyond diminishing supplies of fish, there is also growing concern over pollutants, such as dioxins, mercury, and PCBs in the world's oceans, causing the fish oil and fishmeal produced from these resources to be similarly polluted.
A challenge in fish nutrition is to generate end-products with high levels of health-promoting long chain omega-3 fatty acids for the consumer, while reducing the use of fish oils. This growing concern is another driving force for the marketing of non-marine based omega-3 oils and alternative feed ingredients.
A commendable insight highlighted by a very recent article by Naylor et al (2009)(2) was the use of products from biofuel industry as a source of aquafeed-ingredients. Algal biofuel stands out as the most promising future feedstock. Investors have already shown particular interest towards algae-based biofuel, for example, in USA on a combined basis, biodiesel plus algae venture capital investments totaled $320 million in 2008 – up from the $307 million invested in 2007. Most recently, industry leaders such as Shell, Chevron, ExxonMobil, and British Petroleum have also invested substantial resources (~$1billion) in developing algal-based biofuels.Algae naturally produce substantial amount of omega 3's and at least a fraction of this component can be carved from the extracted lipid intended for biofuel production. Algal meal is rich source of high quality protein, vitamins, micronutrients (trace elements), and carotenoids which can be directly used in aquafeeds (3). Policy initiatives for meaningful integration of aquafeed industries with algal biofuel production sector can bring many sustainable deliverables to society such as renewable supply of aquafeed ingredients, thereby relieving pressure on marine resources.