Effects of Polyunsaturated Fatty Acids Supplementation on The Meat Quality of Pigs: A Meta-Analysis

Abstract Background: Polyunsaturated fatty acids (PUFAs) supplementation has been widely discussed as a strategy for improving meat quality in pig production but the effects are inconsistent. This meta-analysis was performed to comprehensively evaluate its effects on the meat quality including intramuscular fat (IMF) content, drip loss, meat color, pH 45min and pH 24h of pigs.Methods: We searched the PubMed and Web of Science databases (articles published from Jan 1st, 2000, and Oct 16th, 2020) and compared PUFAs-supplemented diets with control diets. We identified 1670 studies, of which 14 (with data for 752 pigs) were included in our meta-analysis. We used a random-effects model and a fixed-effects model to calculate the weighted mean differences (WMDs) and 95% confidence intervals (CIs). We used sensitivity and subgroup analysis to ensure the pooled estimates are robust. The subgroup analysis was classified as treatment (conjugated linoleic acid (CLA) or linseed), concentration (high or low concentration) and initial stage (growing and finishing pigs).Results: Our analysis found that PUFAs supplementation increased the IMF content (WMD= 0.467%, 95% CI: 0.312 to 0.621, P<0.001), decreased the meat color L* (WMD= -0.636, 95% CI: -1.225 to -0.047, P=0.034) and pH 24h (WMD= -0.021,95% CI: -0.032 to -0.009, P<0.001). CLA supplementation improved IMF content (WMD= 0.542%, 95% CI: 0.343 to 0.741, P<0.001) and reduced meat color b* (WMD= -0.194, 95% CI: -0.344 to -0.044, P=0.011). Linseed supplementation increased IMF content (WMD= 0.307%, 95% CI: 0.047 to 0.566, P=0.021), decreased meat color L*(WMD= -1.740, 95% CI: -3.267 to -0.213, P=0.026) and pH 24h (WMD= -0.034, 95% CI: -0.049 to -0.018, P<0.001). We discovered an increase on IMF content in both high and low concentration PUFAs supplementation (WMD= 0.461%, 95% CI: -0.344 to -0.044, P<0.001; WMD= 0.456%, 95% CI: 0.276 to 0.635, P<0.001). Besides, we also found the effects of PUFAs supplementation on meat color L* and pH 24h are concentration- and stage-dependent.Conclusions: PUFAs supplementation can improve meat quality of pigs which mainly emerge in greatly increasing IMF content.