Effects of feeding different levels of conjugated linoleic acid and total oil to pigs on subsequent pork quality and palatability

Abstract

The objective of the present study was to compare pork quality, composition and palatability of pigs fed different levels of conjugated linoleic acid (CLA) and total oil (TO). A 3 × 2 factorial design was used feeding three levels of CLA (0, 0.25, and 0. 5%) and two levels of TO (2 and 5% made up with canola oil). Thirty-six pigs were allotted per diet and diets were fed from 35 to 115 kg liveweight. TO had no effect on longissimus thoracis (LT) moisture or intramuscular fat contents, but feeding CLA decreased LT moisture (P = 0.04) and increased LT intramuscular fat (P = 0.04). CLA and TO had no effect on LT subjective color, structure or marbling scores. Post-mortem LT temperature was also unaffected by feeding CLA or TO. Pigs fed 0.5% CLA had a marginally higher muscle pH (P = 0.01), a tendency toward lower post-mortem lactate levels (P = 0.06) and had higher glycogen concentrations (P = 0.03) at 30 min post mortem. Feeding CLA may thus offer limited protection against rapid post-mortem pH decline. Adding CLA to the diet increased subcutaneous fat hardness (P = 0.01), which was related to increased saturated (P = 0.01) and reduced monounsaturated fatty acid levels (P = 0.01). Increasing TO had an opposite effect resulting in softer fat with lower saturated and higher mono- and polyunsaturated fatty acid levels (P = 0.01). Supplementing diets with CLA in combination with canola oil did not have any detrimental effect on pork quality, composition or palatability. Feeding CLA does, however, have the potential to improve pork quality by increasing intramuscular fat levels, reducing post-mortem glycogen utilization rates and increasing subcutaneous fat hardness. Key words: Conjugated linoleic acid, canola oil, pork quality, palatability, marbling, fat composition