Effects of heat stress on production performance and protein metabolism of skeletal muscle in meat rabbits

Abstract In modern animal husbandry production, rabbits are readily affected by heat stress in summer. A critical issue in rabbit production is to determine the mechanism by which heat stress prevents muscle growth. The purpose of this experiment was to study the effects of heat stress on performance and protein metabolism of skeletal muscle in meat rabbits. A total of 160 New Zealand White rabbits aged 80 days with mean initial body weights of 2359 ± 200 g were randomly divided into the control group and heat stress group. The experiment duration was 20 days. Heat stress treatment reduced the growth performance and slaughter performance of the rabbits (P < 0.05), and increased muscle yellowness (b*, P < 0.05). In addition, heat stress treatment increased the concentrations of leptin, cholesterol, high-density lipoprotein (HDL) cholesterol, and low-density lipoprotein (LDL) cholesterol in serum (P < 0.05), and decreased the serum total protein and immunoglobulin (IgG, IgM, and IgA) contents of rabbits. Under the criteria fold-change ≥ 1.20 or ≤ 0.84 and P-value ≤ 0.05, seven up-regulated proteins and 122 down-regulated proteins were screened. A gene ontology (GO) enrichment analysis of the differentially expressed proteins was performed. The most enriched specific GO terms among the differential proteins were response to stress, extracellular region, and protein binding in the biological process, cellular component, and molecular function categories, respectively, and the most enriched pathway was PI3K/Akt signalling pathway. Heat stress reduced the carcass yield of growing meat rabbits, changed the physical characteristics of the skeletal muscle, influenced protein metabolism by changing blood indices potentially through the PI3K/Akt signalling pathway.