Effects of dietary tributyrin on quality of breast meat in heat-stressed Taihe silky fowls

This research aimed to investigate the impact of tributyrin on breast muscle quality of broilers exposed to heat stress, as well as the underlying molecular mechanisms. Three hundred Taihe silky fowls (16 weeks of age) were assigned to six treatments: a thermoneutral environment treatment (TN, 24 ± 1 °C) fed with basal diet and five heat stress treatments (34 ± 1 °C for 8 h/d) fed with basal diet supplemented with 0, 0.04, 0.08, 0.16, and 0.32% tributyrin, respectively, designated as HS, HST1, HST2, HST3, HST4. This experiment lasted two weeks. Our findings revealed that, compared with the TN treatment, heat stress not only reduced the growth performance but also impaired the quality of breast-meat of broilers. Moreover, heat stress led to mitochondrial damage, increased muscle glycolysis, and reduced antioxidant capacity of breast muscle. However, tributyrin supplementation improved the ADG and reduced the F/G in broilers. Supplementation with tributyrin effectively mitigated heat stress-induced quality deterioration in breast muscle by alleviating the decline in pH_{45 min} and the elevation in drip loss. Additionally, tributyrin supplementation effectively alleviated mitochondrial damage, delayed muscle glycolysis, and improved antioxidant capacity of breast muscles. Further mechanistic investigations revealed that tributyrin supplementation increased mRNA levels of Nrf2, NQO1, HO-1, GSH-Px, and avUCP, while decreasing mRNA levels of Keap1, LKB1, AMPKα2, and M-CPT1 in the breast muscle. In vitro, validation using chicken skeletal muscle cells confirmed tributyrin treatment increasing the mRNA levels of Nrf2, NQO1, HO-1, GSH-Px, LKB1, AMPKα2, while also elevating the levels of phosphorylated AMPK and phosphorylated ACC under heat stress conditions. In conclusion, dietary tributyrin supplementation, particularly at 0.16%, alleviated oxidative damage caused by heat stress in breast muscle by modulating energy metabolism and the Nrf2 pathway-mediated antioxidant system, thereby improving broiler meat quality.