EFFECT OF VEGETABLE OILS SUPPLEMENTATION IN PIG DIETS ON LIPID OXIDATION AND FORMATION OF OXIDIZED FORMS OF CHOLESTEROL IN MEAT

The effects of giving pigs dietary vegetable oils on oxidative stability, cholesterol level and oxysterol formation in their meat were studied. A total of 40 Polish Landrace pigs were randomly allocated to 4 groups with 5 gilts and 5 barrows per group and fattened from 50 to 105 kg body weight. Fat supplements represented the experimental factor: palm oil, linseed oil, rapeseed oil, and sunflower oil given at 3 % of ration dry matter. A significantly higher MUFA level was found in the m. longissimus dorsi of pigs receiving dietary palm oil compared to the linseed oil-fed pigs (p<0.05). There was a highly significant narrowing in the n-6/n-3 PUFA ratio between the experimental groups (p<0.01). In addition, the level of DHA acid was significantly higher in gilts than in barrows (p<0.01). The use of dietary vegetable oils caused a significant decrease in the oxidative stability of meat, in particular after 180 days of frozen storage of meat (p<0.01). A highly significant interaction was found for TBARS between the fat supplement used and sex (p=0.003). There were highly significant differences in vitamin E content of meat between the group receiving palm oil and the linseed oil-fed group (p<0.01). The type of oil had no significant effect on the total cholesterol content of meat. It was found that oxidized forms of cholesterol formed during storage. There were highly significant differences in the level of 7-ketocholesterol between the groups receiving palm oil and sunflower oil and the groups fed linseed oil and rapeseed oil (p<0.01). A similar, highly significant correlation was found between the level of total oxysterols and total cholesterol, with additional differences between the groups receiving linseed oil and rapeseed oil (p<0.01). Highly significant interactions, ranging from p=0.002 to p=0.08, were found between the level of oxysterols, and the source of fat and sex