Characterization of conjugated linoleic acid isomers in Iberian wild red deer

Conjugated isomers of linoleic acid (CLA) occur naturally in ruminant fats, although information on the CLA isomeric profile in venison is scarce. The objective of this study was to evaluate the CLA content of wild Iberian red deer from Montado (savannah-like pastures where cork and holm oaks are the predominant trees). Twenty adult wild Iberian red deers shot during the morning period, were selected. Sampling was performed during afternoon, by removing the psoas major muscles, which were transported under refrigeration to the laboratory. After trimming, samples were frozen (-20 oC) until analysis. The methyl esters of CLA isomers were individually separated and quantified by HPLC. Venison had a total CLA contents of 2.04±0.77 mg/g of lipids and 18.2±7.1 mg/kg of meat (mean ± SD), with the following isomeric distribution (% of total CLA): t12,t14 (5.09%), t11,t13 (3.41%), t10,t12 (2.80%), t9,t11 (1.53%), t8,t10 (3.87%), t7,t9 (4.29%), t6,t8 (2.56%), c/t12,14 (1.86%), t11,c13 (1.60%), c11,t13 (6.19%), t10,c12 (2.85%), c9,t11 (49.53%), t8,c10 (3.16%), t7,c9 (5.53%), c9,c11) (5.72%). The Montado venison showed a particular CLA isomeric profile, with considerably lower percentage of c9,t11 isomer, than is currently reported in other ruminant meats (75 to 90% of total CLA). Introduction The Portuguese Montado is an agro-silvo-pastoral system characteristic of the Portuguese southern province of Alentejo and the bordering western councils of Ribatejo and southern councils of Beira-Baixa provinces [1, 2]. The Portuguese Montado closely resembles the Spanish Dehesa, and both constitute examples of land-use systems well adapted to the environmental restrictions of the Mediterranean region, characterised by low edaphic and climatic potential [3, 4]. Montado land has been managed, for several decades, as an agro-silvo-pastoral system, but nowadays significant areas of this ecosystem are being converted into rural tourism or big game hunting reserves. Together with cork exploitation, they support the economic viability of the land, offering simultaneous preservation of the Montado ecosystem biodiversity and the landscape structure [2]. The red deer (Cervus elaphus) is one of the most appreciated big game hunting trophies in Europe. The Iberian red deer (Cervus elaphus hispanicus) is well adapted to the Montado ecosystem, and represents an important resource to Portuguese big game hunting reserves. In Portugal, venison is a surplus product from the big game hunting industry, which is promoted as gourmet meat due to its unique gamey flavour. Venison nutritional profile (lean meat, low fat and low cholesterol) [5], also attracts meat consumers, principally the health-conscious consumers. Conjugated linoleic acid (CLA), a collective term to all the geometric and positional isomers of linoleic acid (C18:2n-6), exerts positive effects on cancer, cardiovascular disease, diabetes, body composition, immune system and bone health. CLA occurs naturally in food, especially in ruminant-derived fat, presenting an increase value for ruminant’s meat [6], as venison. However, little information is available regarding venison nutritional quality, and there is no available information concerning CLA content and isomeric profile in wild Iberian red deer from Montado. Therefore, it was this study’s purpose the evaluation of CLA content and isomeric profile in wild Iberian red deer from Montado. Material and methods Twenty wild adult Iberian red deers (ten female and ten male), shot during a battue in the morning period, were selected for the study. The psoas major muscles were collected from the cadavers during the afternoon, immediately after the sanitary inspection. The muscles were transported under refrigeration (+5oC.) to the laboratory, stored under refrigeration and processed on the day after. All meat samples were