Li Zhaojian, Wang Yiting, Yuan Peng, Zhu Yanli, Hu Ping, Song Tongxing, Liu Rui, Liu Hao-Yu, Cai Demin
Laboratory of Animal Physiology and Molecular Nutrition, Jiangsu Key Laboratory of Animal Genetic Breeding and Molecular Design, College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, China.
College of Animal Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
Stress Biol. 2024 Sep 14;4(1):39. doi: 10.1007/s44154-024-00182-w.
To assess the effects of a time-restricted feeding (TRF) regimen on meat quality of pigs exposed to high ambient temperature, a two-month feeding and heat treatment (HT) trial was conducted using a 2 × 2 factorial design. A total of 24 growing pigs (11.0 ± 1.9 kg) were randomly divided into four groups: thermal neutral group (NT, 24 ± 3 °C), HT group (exposed to a high temperature at 35 ± 2 °C from 11:00 to 15:00), TRF group and HT + TRF group (HT and TRF co-treatment group, n = 6 for each group). Pigs in TRF groups got access to feed within 5 h from 9:00 to14:00, while the others were fed at 6:00, 11:30, and 16:00. All pigs received the same diet during the trail. The results showed that HT increased the drip loss, shear force, lightness, and malondialdehyde production in Longissimus thoracis et lumborum (LTL) muscle. TRF reversely reduced the shear force and drip loss, accompanied by decreased intramuscular fat and increased moisture content. Enhanced fiber transformation from type 1 to type 2b and down-regulated expression of muscle growth-related genes were observed by HT, while TRF suppressed the fiber transformation and expression of muscle atrophy-related genes. Furthermore, TRF restored the diminished protein expressions of Nrf2 and HO-1 in LTL muscle by chronic HT. Accumulation of HSP70 in muscle of HT group was reduced by treatment of TRF. HT declined the expression of vital genes involved in fatty acids poly-desaturation and the proportion of (polyunsaturated fatty acids) PUFAs, mainly omega-6 in LTL muscle, while TRF group promoted the expression of poly-desaturation pathway and displayed the highest proportion of PUFAs. These results demonstrated that TRF relieved the chronic high temperature affected meat quality by the restored expression of Nrf2/HO-1 anti-oxidative cascade, modified muscle fiber composition, and enriched PUFAs in LTL muscle.
为评估限时喂养（TRF）方案对暴露于高温环境下猪的肉质的影响，采用2×2析因设计进行了为期两个月的喂养和热处理（HT）试验。将24头生长猪（11.0±1.9千克）随机分为四组：热中性组（NT，24±3°C）、HT组（11:00至15:00暴露于35±2°C的高温下）、TRF组和HT+TRF组（HT和TRF联合处理组，每组n = 6）。TRF组的猪在9:00至14:00的5小时内进食，而其他猪在6:00、11:30和16:00进食。试验期间所有猪都接受相同的日粮。结果表明，HT增加了胸腰最长肌（LTL）肌肉的滴水损失、剪切力、亮度和丙二醛生成量。TRF则相反地降低了剪切力和滴水损失，同时伴随着肌内脂肪减少和水分含量增加。HT观察到纤维从1型向2b型转变增强以及肌肉生长相关基因表达下调，而TRF抑制了纤维转变和肌肉萎缩相关基因的表达。此外，TRF恢复了慢性HT导致的LTL肌肉中Nrf2和HO-1蛋白表达的减少。TRF处理降低了HT组肌肉中HSP70的积累。HT降低了LTL肌肉中参与脂肪酸多去饱和的关键基因的表达以及多不饱和脂肪酸（PUFAs）的比例，主要是ω-6，而TRF组促进了多去饱和途径的表达并显示出最高比例的PUFAs。这些结果表明，TRF通过恢复Nrf2/HO-1抗氧化级联反应的表达、改变肌肉纤维组成以及在LTL肌肉中富集PUFAs，缓解了慢性高温对肉质的影响。
