It has been reported that, fat and fatty acids (FA), in adipose tissue or muscle, contribute to various aspects of meat quality. Intramuscular fat (IMF) content may influence sensory quality traits, including flavour, juiciness and tenderness of meat. During the last decades, due to the selection against fatness or P2 backfat thickness, IMF content has been dramatically reduced to less than 1% in some lean genotypes widely used nowadays. For this, a strategic feeding has been carried out; one of them is the inclusion of conjugated linoleic acid (CLA) in feed for growing/finishing pigs for its distributive effect between fat and lean. Sixteen gilts (73 ± 3Kg) were blocked by weight and housed in adjacent individual boxes. Gilts were randomly assigned within block to one of the dietary treatments. Fat source differed between the treatments, eight animals were fed the control diet (4% of sunflower oil) and eight fed the experimental diet (4% conjugated linoleic acid (CLA) oil) for ad libitum consumption.
Growth performance was not affected by CLA inclusion but tended to reduce fat deposition between the last 3th–4th lumbar vertebrae, but increased liver weight, reduced perirenal fat. No effects were observed on intramuscular fat (IMF) content neither in longissimus thoracis (LT) nor in semimembranosus (SM) muscles due to the CLA inclusion. Despite the fact that 9c,11t and 10t,12c CLA isomers were included in the same proportion in the diet, the 9c,11t and 9c,11c were the isomers more deposited in all tissues. Addition of CLA in the diet affected fatty acid composition in a tissue specific manner, increasing percentages of SFA in all tissues, reducing percentages of MUFA in LT and LT subcutaneous fat, and of PUFA in LT subcutaneous fat, liver and SM.
The FA changes by dietary CLA in LT IMF were performed in the different lipid fractions, SFA and MUFA mainly in the neutral lipid fraction, and PUFA in the polar fraction.
Tous, N., Lizardo, R., Vilà, B., Gispert, M., Font-i-Furnols, M., and Esteve-Garcia, E. 2013. Effect of a high dose of CLA in finishing pig diets on fat deposition and fatty acid composition in intramuscular fat and other fat depots. Meat Science, 93:517-524. http://dx.doi.org/10.1016/j.meatsci.2012.10.005