乳腺炎是一种重要的疾病,在临床和亚临床状态下都具有经济和福利意义。这项研究的目的是对16SrRNA基因的高可变V4区域进行测序,以描述来自临床健康母羊的牛奶的微生物多样性和分类学(Rambouillet,WF=9;汉普郡,BF=5)。实验母羊代表了一项大型研究的子集,该研究评估了不同饮食锌(Zn)浓度的影响[1×美国国家科学院,Engineering,在整个妊娠晚期和哺乳期,医学(NASEM)建议=CON或3×NASEM建议=ZnTRT]。在泌乳早期的四个时期收集牛奶(18-24小时,7d,14d,产后21d)和断奶时(产后84±14d)。体细胞计数(SCC)进行定量,平均,并分类(低:<500×103;中:500×103-100×104;高:>100×104细胞/mL)。对牛奶样品(n=67)进行测序以鉴定细菌和古细菌;最丰富的门是放线菌,拟杆菌,蓝细菌,Euryarchoota,Firmicutes,镰刀菌,Lentisphaerae,变形杆菌,螺旋藻,Tenericutes,糖杆菌TM7和Verrucomicrobia。乳腺炎病原体是最丰富的属之一,包括葡萄球菌,Mannheimia,棒状杆菌,和假单胞菌.品种的影响,日粮锌浓度,SCC类,在泌乳早期(使用重复测量模型)和断奶样本中评估了它们对牛奶微生物组多样性和分类学的双向相互作用。Alpha多样性指标包括Pielou的均匀度,信仰的系统发育多样性,和香农的熵指数。锌处理之间的主要和相互作用的影响,品种,SCC类,和时期在泌乳早期是可变的,在断奶样本中不明显。BF母羊的牛奶增加了Faith的系统发育多样性和Shannon的熵,未加权UniFrac成分不同(P≤0.10)。来自CON母羊的牛奶在早期泌乳期间的组成变化速率降低(P=0.02),表明微生物组稳定性比ZnTRT母羊牛奶高。这些结果支持牛奶不是无菌的,和品种,日粮锌浓度,和SCC类别会影响牛奶微生物组。当前研究的结果为增加膳食锌补充对牛奶微生物组纵向变化的影响以及与乳腺健康和乳腺炎的关系提供了重要的基础见解。
Mastitis is an important disease with economic and welfare implications in both clinical and subclinical states. The aim of this research was to sequence the hypervariable V4 region of the 16S rRNA gene to describe the microbial diversity and taxonomy of milk from clinically healthy ewes (Rambouillet, WF = 9; Hampshire, BF = 5). Experimental ewes represented a subset of a larger study assessing the impacts of divergent dietary zinc (Zn) concentrations [1× National Academics of Sciences, Engineering, and Medicine (NASEM) recommendations = CON or 3× NASEM recommendations = ZnTRT] throughout late gestation and lactation. Milk was collected at four periods during early lactation (18 - 24 h, 7 d, 14 d, and 21 d postpartum) and at weaning (84 ± 14 d postpartum). Somatic cell counts (SCC) were quantified, averaged, and classed (low: < 500 × 103; medium: 500 × 103 - 100 × 104; high: > 100 × 104 cells/mL). Milk samples (n = 67) were sequenced to identify bacteria and archaea; the most abundant phyla were Actinobacteria, Bacteroidetes, Cyanobacteria, Euryarchaeota, Firmicutes, Fusobacteria, Lentisphaerae, Proteobacteria, Spirochaetes, Tenericutes, Saccharibacteria TM7, and Verrucomicrobia. Mastitis pathogens were among the most relatively abundant genera, including Staphylococcus, Mannheimia, Corynebacterium, and Pseudomonas. Effects of breed, dietary Zn concentration, SCC class, and their two-way interactions on milk microbiome diversity and taxonomy were assessed within early lactation (using a repeated measures model) and weaning samples. Alpha-diversity metrics included Pielou\'s evenness, Faith\'s phylogenetic diversity, and Shannon\'s entropy indices. Main and interactive effects between Zn treatment, breed, SCC class, and period were variable in early lactation and not evident in weaning samples. Milk from BF ewes had increased Faith\'s phylogenetic diversity and Shannon\'s entropy, and differed in unweighted UniFrac composition (P ≤ 0.10). Milk from CON ewes had a reduced rate of composition change through early lactation (P = 0.02) indicating greater microbiome stability than ZnTRT
ewe milk. These results support that milk is not sterile, and breed, dietary Zn concentration, and SCC class variably affect the milk microbiome. Findings from the current study provide important foundational insights into the effects of increased dietary Zn supplementation on longitudinal changes in the milk microbiome and associations with mammary gland health and mastitis.