—Hyun Sik S. Chu (Water IGEP PhD candidate)
The tilapia aquaculture industry has been enjoying continual increases in seafood market share not only through increased production volume, but via new and innovative product developments. However, the tilapia industry has seen a setback due to the misconceptions by the consumers. The quote, “worse than bacon,” was brought up in 2008 and has been stuck with tilapia in online health food blogs ever since. Highly influential blogs are affecting the consumer behaviors more than ever since. This change in consumption patterns must be addressed to improve the image of tilapia and to develop a healthy relationship between the aquaculture industry and consumers. Also the high consumption of arachidonic acids (ARA; 20:4n-6) have been associated with cardiovascular diseases with detrimental effect on heart health recently. Although controlling for ARA in the diet is important, overall n-6:n-3 ratio is very important factor that must be evaluated. Current US consumers are consuming n-6:n-3 ratios at 10:1 or greater. As cardiovascular disease has been number one cause of death throughout the world, it affects are in global scale.
In order to understand the claims about poor lipid quality of tilapia, fatty acid composition (FAC) of tilapia fillets in US supermarkets were analyzed. The fatty acids of interest that were quantified were the oleic acid (OA; 18:1n-9) at 158.9 ±47.6 mg/g oil, long chain n-3 fatty acids (LCn-3; includes 20:5n-3, 22:5n-3, and 22:6n-3) at 23.5 ±16.3 mg/g oil, and ARA at 13.1 ±4.6 mg/g oil. The variation in samples from different origin of country resulted in high variation within the samples. Regardless, n-6:n-3 ratios values were relatively low at 4.7 ±2.1 compared normal US diets.
Our market study indicated healthy FAC in tilapia fillet lipids. However, to meet the changing demands of consumers for more premium products, we conducted two separate 8 week growth trials to improve FAC through enhanced diets. First trial developed enhanced diets through algae meal or fish oil with corn oil as base. 1, 3, and 5% algae meal or fish oil inclusion in the diets resulted in tilapia fillet lipids with n-6:n-3 ratios of 2.1 ±0.6. Although we addressed improving n-3 fatty acid quality, we still observed high levels of ARA and low levels of OA. Thus, in the second study, we utilized algae oil, fish oil, high oleic sunflower oil and soybean oils at various concentrations. 7% lipid diets that consisted of 15:85 fish or algae oil to high oleic sunflower oil provided high levels of OA (194.9 ±22.0 mg/g oil) and n-6:n-3 ratio of 1.6 ±0.2.Therefore, we observed improvement of reduction in ARA as well as excellent overall n-6:n-3 ratios especially compared to current American diet of 10:1.
The results from these studies show that tilapia products with FAC that are healthy improvement can be produced. More importantly, we can customize the diets to create products with specifically designed lipid content and/or FAC profile. Consumers have shown high interest in these premium value-added products, and tilapia has huge potential in value-added segment of the market place.
This research has been presented at World Aquaculture Society (WAS) meeting 2017 at San Antonio, Texas.