Meta-analysis of vitamin E on intra-muscular fat and muscle fiber diameter of pork

Objective :The effects of vitamin E (VE) supplementation on intra-muscular fat and muscle fiber diameter of pork were investigated. Methods:Randomized controlled trials (RCT) published from January 1990 to June 2013 were collected from ScienceDirect, Google scholar, Web of Science, China National Knowledge Infrastructure database, Wanfang database. The relationship between VEsupplementation and intra-muscular fat and muscle fiber diameter of pork were studied by the RCTs. Meta-analysis was applied to estimate the combined standard mean difference (SMD) and 95% confidence interval (95%CI) , respectively. Results:The number of studies observing intra-muscular fat and muscle fiber diameter was 10 and 7 in 12 included RCTs, respectively. Compared with the controls, the combined SMD (95%CI) of intra-muscular fat of pork supplemented with VEwas 0.77 (-0.04, 1.58) (p=0.06) and the difference wasn't statistically significant. The combined SMD (95%CI) of muscle fiber diameter of pork supplemented with VEwas-1.05 (-1.84, -0.26) (p<0.05) and the difference was statistically significant. Conclusion:Supplementation with VEimproved the pork quality by decreased muscle fiber diameter, but its effects of increasing proportion of pork intra-muscular fat was not significant.