Conjugated linoleic acid changes porcine performance, compositional and meat quality characteristics
Conjugated linoleic acid (CLA), a geometrical and positional isomer of linoleic acid was fed at 0.75% of the diet to growing-finishing pigs. Experiment 1 consisted of 92 pigs fed CLA for varying weight gain from 28 kg to a 115 kg slaughter weight. Treatments included a control diet with 0 kg gain on CLA (T1) and CLA diets at 28 kg, 56 kg and 87 kg of gain (T2, T3, and T4, respectively). Meat quality, objective and subjective, were evaluated. Compared with T1, a linear increase was observed for subjective marbling and firmness scores with increased time on a CLA diet. When T1 and T4 chops were compared for other measures of meat quality, we observed an increase in Hunter b* values, an improvement in water holding capacity, and a decrease in lipid oxidation over days of retail storage due to CIA supplementation. Furthermore, no differences were observed for pH, subjective color, Hunter L* or a* values, or sensory characteristics because of CLA supplementation. Experiment 2 evaluated 64 stress-genotype (normal, carrier, positive) pigs fed 0.75% CLA. Subsequently, growth, performance, carcass, and meat quality characteristics were analyzed. Feed efficiency was improved while 10th rib fat depth was decreased with CLA supplementation, regardless of genotype. Postmortem pH was lower at 3 h with CLA supplementation compared to control diet carcasses. Subjective marbling scores were significantly improved with CLA supplementation in the normal stress-free pigs. Loin chops from CLA fed pigs exhibited higher Hunter L* values over 7 d of self-service shelf storage compared to loin chops from control diet pigs. No differences were attributed to CLA supplementation for Hunter a* values or sensory panel characteristics. Results from these two experiments show that CLA supplementation can improve feed efficiency, decrease backfat, and improve certain aspects of meat quality in growing-finishing pigs at the level of 0.75% in the diet.