Microbiota of the gut, milk, and cowshed environment were examined at two dairy farms managed by automatic milking systems (AMS). Feed, rumen fluid, feces, milk, bedding, water, and airborne dust were collected and the microbiota on each was assessed by Illumina MiSeq sequencing. The most abundant taxa in feed, rumen fluid, feces, bedding, and water were Lactobacillaceae, Prevotellaceae, Ruminococcaceae, Ruminococcaceae, and Lactobacillaceae, respectively, at both farms. Aerococcaceae was the most abundant taxon in milk and airborne dust microbiota at farm 1, and Staphylococcaceae and Lactobacillaceae were the most abundant taxa in milk and airborne dust microbiota at farm 2. The three most prevalent taxa (Aerococcaceae, Staphylococcaceae, and Ruminococcaceae at farm 1 and Staphylococcaceae, Lactobacillaceae, and Ruminococcaceae at farm 2) were shared between milk and airborne dust microbiota. Indeed, SourceTracker indicated that milk microbiota was related with airborne dust microbiota. Meanwhile, hierarchical clustering and canonical analysis of principal coordinates demonstrated that the milk microbiota was associated with the bedding microbiota but clearly separated from feed, rumen fluid, feces, and water microbiota. Although our findings were derived from only two case studies, the importance of cowshed management for milk quality control and mastitis prevention was emphasized at farms managed by AMS.

Milk is an ideal environment for the growth of many microorganisms due to its high nutritional content. A lot of species, including both desirable and undesirable ones, are detected in raw milk, and thus the milk microbiota may affect the quality and safety of dairy products (Quigley et al., 2013). Some bacteria in milk, including members of Lactococcus spp., Lactobacillus spp., Streptococcus spp., Propionibacterium spp., and Leuconostoc spp. can exert a beneficial role in altering the taste, appearance, and texture of milk and dairy products (Quigley et al., 2013). Meanwhile, several psychrotrophic bacteria, e.g. Pseudomonas spp., Bacillus spp., and Acinetobacter spp., have the ability to grow at low temperatures and become a major cause of milk spoilage, persisting and proliferating during cold storage and producing proteases and lipases (Meer, Baker, Bodyfelt, & Griffiths, 1991; Vithanage et al., 2016). Proteases may reduce the nutrient and economic value of milk by the hydrolysis of casein during milk processing, and lipases can convert lipids into free fatty acids, resulting in unexpected flavor and altering organoleptic properties (Hantsis-Zacharov & Halpern, 2007). Purebred Holsteins have been the major breed in dairy farming because of their overwhelming productivity compared with other breeds. The high milk yield of Holsteins, however, often forces the cows to encounter a serious negative energy balance when they enter lactation after parturition. The state of negative energy balance may increase the number of services per pregnancy and

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Scope High‐fat diet (HFD) intake induces gut dysbiosis, inflammation in the peripheral tissues, and a reduction in immunoglobulin A (IgA) coating of gut bacteria, which is related to HFD‐induced insulin resistance (IR). This study evaluates the effect of cyclic nigerosylnigerose (CNN), a dietary fiber that prevents gut inflammation and promotes IgA coating of gut bacteria, on the above‐mentioned HFD‐induced disorders. Methods and results Balb/c mice are fed an HFD and administered CNN for 20 weeks. CNN administration reduces mesenteric adipose tissue weight, colonic tumor necrosis factor α (TNFα) mRNA expression, and serum endotoxin levels and ameliorates HFD‐induced abnormal glucose metabolism. Additionally, CNN administration promotes gut bacteria‐specific IgA secretion and alters IgA reactivity to gut bacteria. The alterations of IgA reactivity to specific bacteria such as Erysipelatoclostridium, Escherichia, Faecalibaculum, Lachnospiraceae genera, and Stenotrophomonas are correlated with mesenteric adipose tissue weight, colonic TNFα mRNA expression, serum endotoxin levels, and a homeostasis model assessment for IR. Conclusion CNN‐induced alterations in IgA reactivity to gut bacteria may be related to the suppression of HFD‐induced fat deposition, colonic inflammation, endotoxemia, and IR. These observations indicate that dietary fiber that modulates IgA reactivity to gut bacteria may be useful in preventing HFD‐induced disorders.

Mol. Nutr. Food Res. 2023, 67, 202200389 DOI: https://doi.org/10.1002/mnfr.202200389 Oral administration of cyclic nigerosylnigerose (CNN), a dietary fiber, ameliorates abnormal glucose metabolism, fat deposition, and colonic inflammation in mice with high‐fat diet‐induced obesity. Impressively, the CNN‐induced effects are accompanied by an alteration of gut immunoglobulin A (IgA) reactivity to commensal gut bacteria. This is reported by Takeshi Tsuruta and co‐workers in article number 2200389.