Dietary conjugated linoleic acid improves carcass leanness without altering meat quality in the growing pig

One constraint facing the pig industry is that <i>ad libitum</i> feeding can often result in high levels of body fat and technologies which can reduce the ratio of lean to fat deposition in the pig are continually being explored. Conjugated linoleic acids have been shown to decrease body fat content in pigs. Therefore, the aim of this study was to determine whether dietary conjugated linoleic acids supplementation has any effect on meat quality and carcass characteristics in finisher pigs. Sixty female crossbred (Large White × Landrace) pigs (average initial weight 56.6 ± 1.9 kg and average initial P2 backfat 11.4 ± 1.3 mm) were used in the present study. Pigs were individually housed and randomly allocated to 1 of 6 dietary treatments: 0, 0.125, 0.25, 0.50, 0.75 or 1.0% (w/w) of conjugated linoleic acids-55. The wheat-based diets were formulated to contain 14.3 MJ DE and 9.3 g available lysine per kg and were fed <i>ad libitum</i> for 8 weeks. Pigs were slaughtered and meat quality was determined on the <i>longissimus thoracis</i> using standard techniques. Dietary conjugated linoleic acids reduced subcutaneous back fat in a linear manner with effects being most pronounced in the middle back fat layer. There was also a linear (<i>P</i><0.001) decrease in intramuscular fat with increasing dietary conjugated linoleic acids supplementation. However, there was no effect of conjugated linoleic acids on subjective measures of marbling of the loin. Also, loin muscle ultimate pH (<i>P </i>= 0.94), lightness values (<i>P</i> = 0.46) subjective colour scores (<i>P</i> = 0.79), cooking loss (<i>P</i> = 0.71), drip loss (<i>P</i> = 0.40), shear force (<i>P</i> = 0.61) and subjective measures of wetness/firmness (P = 0.19) were unaffected. Dietary conjugated linoleic acids did not alter oxidation, as measured by the level of TBARs at day 1 post-slaughter (<i>P</i> = 0.38) or after 9 days of simulated retail display (<i>P</i> = 0.35). These data confirm that dietary conjugated linoleic acids can improve carcass quality by decreasing back fat depths without having any detrimental effects on meat quality.<br />