Dietary Conjugated Linoleic Acid Can Decrease Backfat in Pigs Housed under Commercial Conditions

Abstract

Conjugated linoleic acids (CLA) have been shown to decrease body fat content of individually-housed pigs but little is known about the responses under commercial conditions. Two studies were conducted to evaluate the effect of CLA under commercial conditions using contemporary genotypes. The experimental designs were similar between the two sites. Briefly, the studies were 22 factorial designs with the respective factors being sex (boar and gilt) and supplemental dietary CLA (0 and 4 g/kg). The studies involved 16-20 pens of pigs with 4-5 pens of each sexCLA group. The first study was conducted with 144 pigs in 16 pens consuming a pelleted feed for 6 weeks at Bunge Meat Industries, Corowa, NSW. In the second study, 160 pigs were obtained from a commercial source and put into 20 pens in simulated commercial conditions and fed a mash diet for 7 weeks at Medina Research Station, WA. In Study 2 some aspects of meat quality were also investigated. Data from Study 1 showed that, although CLA had no significant effect upon feed intake and daily gain, the small changes in both resulted in a reduction in (-0.10 g/g, p=0.10) feed conversion ratio (FCR). While there was no significant effect of CLA on ultrasonic backfat depths, there was a significant decrease in carcass P2 (-1.0 mm, p=0.014) and estimated carcass fat (-7 g/kg, p=0.049). In the study conducted at Medina CLA had no significant effect upon feed intake, feed:gain or most measures of back fat. The exception was that dietary CLA decreased the rate of accumulation of fat at the shoulder, particularly in gilts, resulting in a significantly lower amount of shoulder fat at slaughter (-1.3 mm, p=0.044). CLA tended to increase dressing percentage although this was not significant (+0.5%, p=0.14). Meat from CLA treated pigs tended to be darker (p=0.12) and had a higher ultimate pH (p=0.06). These data suggest that under commercial conditions dietary CLA can improve growth performance and decrease P2 in pigs of an improved genotype, particularly gilts. (