Authentication of Farmed and Wild Turbot (Psetta maxima) by Fatty Acid and Isotopic Analyses Combined with Chemometrics

Abstract

Fatty acid composition and stable isotope ratios of carbon (delta(13)C) and nitrogen (delta(15)N) were determined in muscle tissue of turbot (Psetta maxima). The multivariate analysis of the data was performed to evaluate their utility in discriminating wild and farmed fish. Wild (n=30) and farmed (n=30) turbot of different geographical origins (Denmark, The Netherlands, and Spain) were sampled from March 2006 to February 2007. The application of linear discriminant analysis (LDA) and soft independent modeling of class analogy (SIMCA) to analytical data demonstrated the combination of fatty acids and isotopic measurements to be a promising method to discriminate between wild and farmed fish and between wild fish of different geographical origin. In particular, IRMS (Isotope Ratio Mass Spectrometry) alone did not permit us to separate completely farmed from wild samples, resulting in some overlaps between Danish wild and Spanish farmed turbot. On the other hand, fatty acids alone differentiated between farmed and wild samples by 18:2n-6 but were not able to distinguish between the two groups of wild turbot. When applying LDA isotope ratios, 18:2n-6, 18:3n-3, and 20:4n-6 fatty acids were decisive to distinguish farmed from wild turbot of different geographical origin, while delta(15)N, 18:2n-6, and 20:1n-11 were chosen to classify wild samples from different fishing zones. In both cases, 18:2n-6 and delta(15)N were determinant for classification purposes. We would like to emphasize that IRMS produces rapid results and could be the most promising technique to distinguish wild fish of different origin. Similarly, fatty acid composition could be used to easily distinguish farmed from wild samples.

Seasonal variations in chemical composition and stable isotopes of farmed and wild Brazilian freshwater fish

“…This condition factor assumes that, for a given length, heavier fish have better nutritional conditions in their diet (Busetto et al, 2008;Morton & Routledge, 2006). The Fulton's condition factor was higher in farmed cachara than in wild in the rainy season (p < 0.05) (Table 2).…”

“…At present, international fish trade is strongly influenced by food authenticity and safety norms, and several European Directives have introduced regulations concerning quality and safety standards into the fish production chain (Busetto et al, 2008).…”

Genetic population structure in flatfishes and potential impact of aquaculture and stock enhancement on wild populations in Europe

“…Identification of farmed strains, with the initial purpose of controlling origin of commercial fishes, can be done with tools developed to discriminate between farmed and wild marine fishes. In turbot, for example, fatty acid and isotopic analysis may allow to discriminate between wild and farmed strains (Busetto et al 2008). In general, the consequences of stock enhancement and the potential for escapes are not properly monitored (Cross 2000); the utility of genetic tools in such monitoring is important.…”

Application of stable isotope analysis to differentiate shrimp extracted by industrial fishing or produced through aquaculture practices

“…Differences in the availability of dietary elements can partially explain the higher isotopic variability (␦ 13 C VPDB and ␦ 15 N AIR ) observed in wild shrimps as compared with farmed shrimps. In studies conducted on fish, Bell et al (2007) reported higher variability of ␦ 13 C VPDB values in lipids of European seabass (D. labrax), while Busetto et al (2008) reported higher isotopic variability (two-to sixfold) in muscle tissue of wild turbot (Scophthalmus maximus, cited as Psetta maxima) as compared with farmed animals. The lower isotopic variability observed in farmed animals can be attributed to the constant availability of formulated feed for these individuals.…”