Dietary conjugated linoleic acid changes belly and bacon quality from pigs fed varied lipid sources1

Abstract

The objective of this experiment was to determine the effects of dietary lipid source with or without the addition of CLA on bacon composition and quality. Forty-eight barrows at a beginning BW of 55 kg +/- 2.2 were fed 1 of 6 diets for 56 d. These diets consisted of: 1) normal corn (NC), 2) NC + 1.25% CLA-60 oil (NC + CLA), 3) high-oil corn (HOC), 4) HOC + 1.25% CLA-60 oil (HOC-CLA), 5) NC + choice white grease (CWG; NC + CWG), and 6) NC + CWG + 1.25% CLA-60 oil (NC + CWG + CLA). The CLA-60 contains 60% CLA isomers in the oil, and therefore, 1.25% oil was needed to achieve 0.75% CLA in the diet. Soy oil replaced CLA in control diets. Choice white grease and high-oil corn were selected as fat sources for this study because of their utility in energy density for growing-finishing pigs, especially in hot weather. Pigs were slaughtered at an average BW of 113 kg +/- 4.1, and carcasses were fabricated at 24 h postmortem. Statistical analysis was performed using the mixed model procedure of SAS, and the main effects tested were dietary lipid source, CLA, and 2-way interaction. The addition of CLA to each basal diet improved (P < 0.05) belly firmness measured either lean side down or fat side down from the belly bar firmness test [4.39 cm vs. 7.01 cm (lean down) and 5.75 cm vs. 10.54 cm (fat down)] for 0 and 0.75% dietary CLA, respectively. The compression test used on bacon slabs showed that bacon from CLA-supplemented pigs was approximately 20% firmer than that from controls. Pigs fed the HOC diets had softer bellies compared (P < 0.05) with pigs fed the NC diet as measured by the belly bar test [6.94 cm vs. 9.26 cm (fat down)], respectively. Conjugated linoleic acid did not, however, improve bacon sliceability. No differences were observed for moisture, protein, or lipid percentages between any treatments. Overall, there was a CLA effect (P < 0.04) for lipid oxidation, in which the addition of CLA decreased bacon oxidation (0.1498 CLA vs. 0.1638 no CLA). Dietary CLA increased the percentage of SFA in tissues from pigs supplemented with CLA. Dietary inclusion of CLA increased the concentration of all measured isomers of CLA in bacon. Sensory scores of bacon showed no differences for any of the sensory attributes measured between any of the treatments. Our results indicate that inclusion of dietary CLA will improve belly firmness, extend the shelf life stability of bacon, and increase the degree of fat saturation.

Dietary CLA supplementation and gender modify fatty acid composition of subcutaneous and intramuscular fat in Iberian × Duroc finishing heavy pigs

“…In the present study subcutaneous backfat SFA increased from 40.0% to 44.5% during 42 days of experiment, but Larsen et al (2009) found that SFA increased from 38.5% to 46% during 56 days, thus suggesting that in finishing heavy pigs 42 days supplementation with CLA is enough to modify backfat SFA. The lowering PUFA concentration of CLA in subcutaneous fat is also a subject of potential interest, since there is a negative relationship between PUFA content and fat consistency.…”

“…This result is also in agreement with data from Eggert et al (2001), Smith et al (2002) and Martín et al (2007) and might suggest that the t10,c12 isomer would be either less efficiently incorporated or have a different metabolism. On the other hand, Larsen et al (2009) found in lean pigs 1.19 and 0.93% of c9,t11-CLA and t10,c12-CLA respectively in bacon from pigs fed 1% CLA enriched diets for 56 days. However, it is noticeable that despite similar experimental conditions in our study the concentration of both isomers were considerably lower (0.33 and 0.18% for c9,t11-CLA and t10,c12-CLA respectively), than in the study of Larsen et al (2009).…”

“…On the other hand, Larsen et al (2009) found in lean pigs 1.19 and 0.93% of c9,t11-CLA and t10,c12-CLA respectively in bacon from pigs fed 1% CLA enriched diets for 56 days. However, it is noticeable that despite similar experimental conditions in our study the concentration of both isomers were considerably lower (0.33 and 0.18% for c9,t11-CLA and t10,c12-CLA respectively), than in the study of Larsen et al (2009). The main distinctive characteristic between these two experiments is the marked adipogenicity of Iberian pigs (López-Bote, 1998).…”

“…At the moment, most studies with CLA feeding to pigs have been performed on lean (Ostrowska et al, 1999;Martín et al, 2007;Larsen et al, 2009) or moderately fat pigs (Eggert et al, 2001;Fernández-Figares et al, 2008; but there is lack of information of the possible effect of CLA on heavy fat pigs.…”

Effect of Dietary Inclusion of Conjugated Linoleic Acid on Quality Indicators of Aged Pork Loin

“…A positive relationship exists between intramuscular lipid content and sensory attributes of pork such as texture, tenderness, flavor and juiciness (Lonergan et al, 2007); therefore, increasing marbling scores may positively impact fresh pork quality. Inclusion of unsaturated fatty acids in animal feed may cause meat to be softer and less shelf-life stable due to a greater predisposition to fatty acid oxidation (Larsen, Swan, Sparks, Wiegand, & Parrish, 2009); however, CLA, also an unsaturated fatty acid, will improve growth rates of finishing hogs and increase the firmness of the meat (Larsen et al, 2009;Wiegand et al, 2002). Barnes, Winslow, Shelton, Hlusko and Azain (2012) showed that the loins of CLA-fed hogs had a greater proportion of saturated fatty acids and a slight increase of marbling when compared to non-CLA-fed hogs.…”