Fatty Acid Composition of Free-range Rearing of Pigs

Background and methodology
In Sweden, a new generation of consumers chooses meat products not only according to eating quality and price, but also considers the ethical quality of the meat. Another reason for choosing ecologically or non-intensively produced meat is the belief that the taste and nutritional value of this type of meat is superior to that produced conventionally. It is therefore important to investigate how free-range rearing influences the quality of pork. This study was therefore designed to explain the effect of outdoor rearing, pasture grazing, RN genotype and sex of the animals on pork quality. A total of 60 Hampshire crossbred pigs were reared outdoors for two months with access to green feed, while 60 others were kept indoors. From the 120 animals, a sample of 44 animals was chosen for meat quality analysis. 

Outdoor pigs had higher levels of polyunsaturated fatty acids (PUFA) in the intramuscular fat (P=0.026) and an increased level of vitamin E (P=0.030) compared with pigs reared indoors. Meat from female animals with the RN- gene and reared outdoors, had a higher lean meat percentage and produced increased levels of the lipid oxidation product malondialdehyde when stored at -20 degrees C (-13 degrees F) for three months.

Nilzén, V., Babol, J., Dutta, P. C., Lundeheim, N., Enfält, A-C. & Lundström, K. (2001). Free range rearing of pigs with access to pasture grazing-effect on fatty acid composition and lipid oxidation products. Meat Science 58:267-275.