Polyunsaturated Fatty Acid Content of Wild and Farmed Tilapias in Thailand:  Effect of Aquaculture Practices and Implications for Human Nutrition

Abstract

The total lipid content and fatty acid composition of the muscle tissue of tilapia (Oreochromis niloticus) and of hybrid red tilapia (Oreochromis sp.) from different culture systems and from the natural and artificial environment of Thailand were compared. Wild fish and fish reared under the most extensive conditions had a more favorable fatty acid profile for human consumption as they contained higher proportions of 18:3n-3, 20:5n-3, and 22:6n-3, higher n-3/n-6 PUFA ratios, and lower proportions of 18:2n-6. The muscle tissue of intensively cultured fish was characterized by increased fat deposition that was mainly saturated and monounsaturated fatty acids and 18:2n-6. It is undesirable for the consumer to reduce 20:5n-3 and 22:6n-3 in farmed tilapia and replace them with elevated 18:2n-6. It is recommended that the amount of 18:2n-6 in the feed of the intensively reared tilapia should be reduced by substituting vegetable oils rich in 18:2n-6 with oils rich in 18:1n-9 and/or 18:3n-3.

Replacement of Dietary Fish Oils by Alpha‐Linolenic Acid‐Rich Oils Lowers Omega 3 Content in Tilapia Flesh

“…This was true for all individual SFA, including the two major saturates 16:0 and 18:0. These findings are consistent with a previous study with tilapia sampled from various culture systems and sites, where, despite differences in feed inputs, fish displayed similar levels of SFA in their muscle tissues [28]. Similar findings have been reported for salmonids [24,29] and for a red hybrid of tilapia [23].…”

Fatty acid profile of fillet, liver and mesenteric fat in tilapia (<i>Oreochromis niloticus</i>) fed vegetable oil supplementation in the finishing period of fattening

“…Two are promoters (atherogenic and thrombogenic SFAs) and five are protective (PUFA of the n-6 series, PUFA of the n-3 series, MUFA, dietary fibre, and antioxidants). Karapanagiotidis et al (2006) reported on the elevated level of SFA and MUFA in the fillet of intensively farmed tilapia due to the increased fat deposition characterised mainly by SFA, MUFA and LA. They recommend the substitution of vegetable oils rich in LA with oils abundant in oleic acid and ALA.…”

“…Since tilapia grows rapidly on formulated feeds with lower protein levels and tolerates higher carbohydrate levels than many carnivorous farmed species, it is ideal for intensive costeffective recirculation systems. Karapanagiotidis et al (2006) reported that in case of tilapia, the wild fish and fish reared under the most extensive conditions had a more favourable fatty acid profile for human consumption as they contained higher proportions of ALA, EPA, and DHA, higher n-3 to n-6 PUFA ratios, and lower proportions of linoleic acid (LA,. Muscle tissue of intensively cultured fish was characterized by increased fat deposition, consisting mainly of saturated and monounsaturated fatty acids and LA.…”

Passing the Panda Standard: A TAD Off the Mark?

“…Furthermore, results of research indicate that reductions in the natural food produced in situ in tilapia diets through the intensification of feeding regimes results in a progressive negative alteration in ratios of omega-3 and omega-6 fatty acids, rendering them less valuable for human consumption in nutritional terms (Karapanagiotidis et al 2006). These factors suggest that drivers for intensification justified in terms of superior product quality may be misplaced, particularly when more holistic values are considered.…”

“…These producers are unlikely to be able to afford subsequent communications challenges to remedy any incorrect perceptions the market has formed. If the stated ultimate goal of the WWF's (2008c) Web page: ''to build a future where people live in harmony with nature'' (Karapanagiotidis et al 2006) is to be achieved with respect to tilapia, then significant redirection is required. Assumptions on which the current TAD process is founded contain sufficient fundamental flaws to clearly fail this challenge.…”