MODIFICATION OF THE N-3 POLYUNSATURATED FATTY ACIDS CONTENT IN MUSCLE TISSUE OF PIGS

The objective of the research was to find out which combinations of oils give a desirable effect on n-3 PUFA content modification and total values increase in pigs’ meat without negative effects on fattening characteristics and carcass and meat quality of. The standard daily fattening pigs’ diet was supplemented with combinations of fish, linseed and rapeseed oils. The control group (A) received 3% of animal (pork) fat in their diet while 4 experimental groups received the following oil combinations: fish oil 0.5% + rapeseed oil 2.5% (B); fish oil 0.5% + linseed oil 2.5% (C); fish oil 1.0% + rapeseed oil 2.0% (D), and fish oil 1.0% + linseed oil 2.0% (E). The experiment was carried out in the last 4 weeks of fattening. A random sample of 50 pigs (Duroc x Swedish Landrace x Pietrain) was divided into 5 groups with 10 pigs each of the equal ratio of both sexes. The results showed that the treatment and the sex statistically did not significantly influence daily gains whereas the interaction of the treatment and the sex did have a significant influence (p<0.05). Statistically significant influence of the treatment and the sex was observed on the loin muscle thickness (p<0.05) as well as a highly significant influence of the sex on the carcass muscle tissue (p<0.001). Statistically significant influences between groups were not observed for carcass weight, carcass length (A and B) or the ham measures (length and perimeter). It was also found that there were no significant influences of different treatments on ham and MLD pH24, CIE L* meat colour or cooking loss. However, a highly significant influence of the sex on the colour of meat a* and WBSF (p<0.001) as well as the influence of the treatment on meat juice loss were found. For the colour of meat a* and b*, the loss of meat juice, as well as WBSF a significant influence (p<0.05) of the treatment/ sex interaction was found. It was also found that the sex and the interaction between the treatment and the sex significantly influenced the fat content (p<0.05). The sex and the treatment did not significantly influence the content of n-6 PUFA in the pigs’ MLD. A statistically high influence of treatment was noted on the content of n-3 PUFA (α-LNA, EPA and DHA) (p<0.01), except on the content of DPA (p=0.122). The pigs groups of both sexes fed linseed oil (treatments C and E) had the highest content of α-LNA. Statistically, there were no significant differences (p>0.05) between the content of DHA in MLD in treatments A, B, and C. Increasing the content of fish oil in meals from 0.5% to 1% (treatments D and E) produced a statistically significant increase of the DHA content compared to other groups (A, B, and C). The supplement of rapeseed oil (2%) and fish oil (1%) in pigs’ meals (treatment D) influenced significantly higher disposal of n-3 PUFA in MLD compared to pigs fed with the supplement of 3% animal fat (treatment A). The ratio n-6/n-3 PUFA u MLD was statistically highly influenced (p<0.001) by the feeding treatment. The n-6/n-3 PUFA ratio ranged from 4.65:1 (barrows in treatment C) to 20.14:1 (barrows in treatment A). The best n-6/n-3 PUFA ratio was observed in fattening pigs of both sexes from treatment C (5.00:1). Fattening pigs fed the combination of linseed oil and fish oil (treatments C and E) had a better n-6/n-3 PUFA ratio in MLD (p<0.05, 5.00:1 and 6.33:1) compared to the fattening pigs fed the combination of rapeseed oil and fish oil (12.84:1 and 10.04:1).