Supplementation of Either Conjugated Linoleic Acid or γ-linolenic Acid with or without Carnitine to Pig Diet Affect Flavor of Pork and Neutrophil Phagocytosis

In this study, four different oils containing either CLA, GLA, GLA+Carnitine or corn oil (control) were supplemented to finishing pigs (average 70.8 kg initial BW) diet for 28 d of feeding period. To evaluate the values of the dietary fatty acids, especially in view of sensory and nutritional characteristics of pork; pig performances, carcass characteristics, serum cholesterol, neutrophil phagocytosis, TBARS, electronic nose flavor and fatty acids profile of pork were measured. There were no differences in daily gain and nutrients digestion among treatments, but daily feed intake of CLA enriched diet was lower (P<0.05) than that of other diets. There were no differences in backfat thickness, dressing percentage and carcass grade among pigs fed diets supplemented with different oils. Serum total cholesterol showed a tendency to be lowered in pigs fed GLA enriched diet. TBARS values during storage of pork were higher in belly from pigs fed control diet whereas the values of belly from pigs fed GLA+Carnitine diet were lower than others. However, difference in TBARS was not remarkable in adipose tissue and 4 weeks extended storage regardless of pork parts. Proportion of saturated fatty acids such as C16:0 and C18:0 were higher (P<0.05) in pork loin and thin skirt from pigs fed CLA enriched diet compared to those from other diets. There were no differences in fatty acids profiles of belly and adipose tissue. CLA accumulation in pork was increased by the dietary CLA supplementation and this could be also confirmed by a slight de novo synthesis of CLA in pork from pigs fed CLA free diets. GLA was selectively accumulated to pork adipose tissue and loin from pigs fed GLA enriched diets. There was no accumulation of GLA when GLA was not supplemented, indicating no de novo synthesis of GLA. Phagocytic activity was the highest (p<0.05) in neutrophil of pigs fed GLA+Carnitine supplemented diet, then, followed by pigs fed GLA supplemented diet. There was no difference in phagocytosis between control and CLA treatment although the phagocytosis was numerically lowest in pig fed CLA enriched diet. There were distinct differences in electronic nose flavor pattern among treatments regardless of the parts. This study showed that dietary supplementation of functional fatty acids like CLA or GLA was able to result in characteristic differences in feed intake, TBARS, fatty acids profile and flavor of pork, serum cholesterol regulation and neutrophil phagocytosis.