Dietary Eucommia ulmoides leaf extract supplementation improves antioxidative status, meat quality, and structure of cecal microbiota in finishing pigs

The growing demand for high-quality pork has prompted studies on dietary supplements like <i>Eucommia ulmoides</i> leaf extract (ELE). This research evaluated ELE's impact on antioxidants, meat quality, and cecal microflora in finishing pigs. A total of 120 healthy pigs (Duroc × Large White × Landrace, 150-d old, body weight 91.50 ± 0.33 kg) was assigned to four groups, each receiving a basal diet or diet containing 0.015%, 0.030%, and 0.050% ELE. The experimental period lasted 45 d. <i>E</i>. <i>ulmoides</i> leaf extract did not affect growth performance but significantly reduced serum low density lipoprotein and total cholesterol levels (<i>P</i> < 0.05), and increased the glutathione levels of serum and liver (<i>P</i> < 0.001). Additionally, ELE decreased malondialdehyde in serum and the longissimus dorsi muscle (LDM) (<i>P</i> < 0.05), and enhanced superoxide dismutase activities of liver (<i>P</i> = 0.026) and LDM (<i>P</i> = 0.018). Meat quality was improved by ELE, as evidenced by a reduced drip loss (<i>P</i> = 0.017), while increased LDM pH, redness (a∗) value, oleic acid content, and total monounsaturated fatty acids content at the highest ELE dose (<i>P</i> < 0.05). Moreover, a 0.050% ELE diet significantly enhanced muscle fiber density (<i>P</i> = 0.034) and showed a trend towards elevating intramuscular fat content (<i>P</i> = 0.069). These findings revealed that 0.050% ELE up-regulated the expression of myosin heavy chain (<i>MyHC</i>) <i>IIa</i>, peroxisome proliferator activated receptor gamma, fatty acid binding protein 4, and ATP citrate lyase, while down-regulating the expression of <i>MyHCIIb</i> and hormone-sensitive lipase genes, confirmed by real-time quantitative PCR (RT-qPCR) validation. And ELE significantly enriched beneficial bacteria and reduced harmful bacteria at both phylum and genus levels (<i>P</i> < 0.05). Spearman's analysis indicated a correlation between microflora and health and meat quality. Overall, ELE supplementation improved antioxidative status, meat quality, and structure of cecal microbiota in finishing pigs, and meat quality was correlated with the improvement in cecal microbiota.