应用蛋白质组学技术探讨NH3对肉鸡肌内脂肪沉积的分子机制

Intramuscular fat (IMF) content reduction resulting in meat quality decline in broilers, causing huge economic losses to the poultry industry, seriously restricts the healthy and sustainable development of broiler industry. Our previous study found that environmental ammonia (NH3) in houses influences lipids metabolism, changes the distribution of body fat, reduces lipid content in breast muscle and meat quality, however, there were few detailed studies on intramuscular fat deposition influenced by ammonia and related molecular mechanisms are not yet clear in broilers. In this study, broiler chicken models exposed to different concentrations of ambient ammonia are established in programmed artificial climate chambers. Based on this, this research focus on three aspects as follows: (1) intramuscular fat content and meat quality related parameters of broilers exposed to ammonia are tested, to reveal the relationship between ammonia and intramuscular fat deposition and meat quality; (2) the effect of ambient ammonia on lipid metabolism and body fat distribution, to study the mechanism of intramuscular fat deposition influenced by ambient ammonia; (3) Using iTRAQ proteomics, in combination with bioinformatics, molecular biological technology and methods etc. to screen differential expression proteins in breast muscle of broilers exposed to different concentrations of ammonia, preliminary elucidating the molecular mechanism and protein-protein interaction network of intramuscular deposition in broilers. The study could provide theory foundations and technical assistance for the improvement of commercial broiler meat quality, the scientific management and environmental control of broiler chicken houses.

鸡肉肌内脂肪含量降低导致肉品质下降、给肉鸡产业造成巨大的经济损失，严重制约肉鸡产业的健康可持续发展。前期研究发现，舍内高浓度氨气影响肉鸡脂代谢、改变体脂分布、降低胸肌含脂率及肉品质，但氨气对肉鸡肌内脂肪沉积的研究较少，相关的分子机制尚不清楚。本项目拟采用人工气候实验舱构建不同氨气浓度暴露的肉鸡模型，重点研究：（1）氨气暴露下的肉鸡肌内脂肪含量和肉品质参数，以揭示氨气与肌内脂肪沉积及肉品质的关系；（2）氨气暴露对肉鸡脂代谢和体脂分布的影响，以明确氨气影响胸肌肌内脂肪沉积的机制；（3）应用iTRAQ蛋白质组学结合生物信息学、分子生物学等技术方法深入挖掘氨气刺激抑制肌内脂肪沉积的差异蛋白质，初步阐明氨气影响肉鸡肌内脂肪沉积的分子机制和作用网络。为商品肉鸡肉品质的提高、鸡舍的科学管理和环境控制提供理论依据和技术支持。

氨气作为畜禽舍内最主要的有毒气体，严重影响动物的健康和生产性能，危害现代肉鸡产业的长期可持续发展。前期研究发现，长期氨气暴露危害家禽健康，尤其是呼吸道健康和肉品质。本项目采用人工气候实验舱构建不同氨气浓度暴露的肉鸡模型，采用RNA-Seq高通量测序技术研究氨气对肉鸡胸肌基因表达的影响，筛选差异表达的候选基因，以期为遗传育种和营养调控提高鸡肉产量和肉品质提供理论依据。研究发现，25 ppm 氨气显著降低肉鸡屠宰性能和胸肌产量（P < 0.05）； 高通量测序筛选到胸肌 163 个差异表达的基因（P < 0.05； FC ≥ 2），其中， 96 个基因表达下调， 67 个表达上调； GO 和 KEGG 分析表明，差异表达基因参与脂质合成、糖脂代谢和脂肪酸代谢等能量代谢途径。本研究为遗传育种和营养调控提高鸡肉产量和肉品质提供了理论依据、为改善畜禽舍环境和动物福利奠定了基础，同时为鸡舍的科学管理和环境控制提供理论依据。