Wang Diming, Cai Jie, Wang Bing, Ding Shengsen, Guan Le Luo, Liu Jianxin
Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China; Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada.
Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China.
Genomics. 2021 May;113(3):1522-1533. doi: 10.1016/j.ygeno.2021.03.024. Epub 2021 Mar 24.
The enriched nitrogenous compounds in the dairy farms negatively affect the surrounding soil quality and air condition. The objective of this study is to investigate the transcriptomes of five key tissues involved in nitrogen metabolism and their changes under different diets to elucidate the molecular regulatory mechanisms of urine urea nitrogen (UUN) yield, one of the indicators of nitrogenous compound secretion of dairy cows.
Cows fed high quality forage-based diet had lower UUN content and UUN yield, compared to those fed low quality forage (crop byproducts) based diets. From the transcriptomes of rumen, duodenum, jejunum, liver and udder, key driver genes and their UUN yield-associated functional gene networks were identified. In addition, the functional networks and expression of key drivers in various tissues (such as S100A8, CA1 and BPIFA2C in the duodenum; A2ML1, HMGCS2 and S100A12 in the jejunum; CYP2B6 and GLYCAM1 in the liver; APOE in the udder) changed in the cows fed crop byproducts based diet, which might be the predominant molecules to drive the increase UUN yield in these cows.
The information suggested that gut, liver and udder play important roles in regulating UUN yield, which could regulate nitrogen excretion waste. These findings provide fundamental information on future nutritional intervention strategies to reduce the UUN yield from dairy cows fed human inedible crop byproducts, which is vital for a sustainable and environmentally friendly dairy industry.
奶牛场中富含的含氮化合物对周围土壤质量和空气质量产生负面影响。本研究的目的是调查参与氮代谢的五个关键组织的转录组及其在不同日粮下的变化，以阐明尿尿素氮（UUN）产量的分子调控机制，UUN产量是奶牛含氮化合物分泌的指标之一。
与饲喂低质量粗饲料（农作物副产品）日粮的奶牛相比，饲喂高质量粗饲料日粮的奶牛UUN含量和UUN产量较低。从瘤胃、十二指肠、空肠、肝脏和乳房的转录组中，鉴定出关键驱动基因及其与UUN产量相关的功能基因网络。此外，在饲喂农作物副产品日粮的奶牛中，各组织中的关键驱动基因（如十二指肠中的S100A8、CA1和BPIFA2C；空肠中的A2ML1、HMGCS2和S100A12；肝脏中的CYP2B6和GLYCAM1；乳房中的APOE）的功能网络和表达发生了变化，这可能是导致这些奶牛UUN产量增加的主要分子。
这些信息表明，肠道、肝脏和乳房在调节UUN产量方面发挥着重要作用，这可以调节氮排泄废物。这些发现为未来的营养干预策略提供了基础信息，以降低饲喂不可食用农作物副产品的奶牛的UUN产量，这对可持续和环境友好型奶牛业至关重要。
