Breast milk is essential for the initial development of neonatal animals, as it provides not only essential nutrients and a broad range of bioactive compounds but also commensal bacteria. The milk microbiota contributes to the “initial” intestinal microbiota of infants and also plays a crucial role in modulating and influencing neonatal health. However, the milk microbiota of sows has yet to be systematically investigated. The goal of the present study was to characterize variations in bacterial diversity and composition in sow milk over the duration of lactation using a high-throughput sequencing approach. Milk samples (n = 160) were collected from 20 healthy sows at eight different time points, and microbial profiles were analyzed by 16S ribosomal RNA (rRNA) sequencing using the Illumina MiSeq platform. The composition and diversity of the milk microbiota changed significantly in colostrum but was relatively stable in transitional and mature milk. Firmicutes and Proteobacteria were the most dominant phyla in sow milk. The relative abundances of the two most dominant bacterial genera, Corynebacterium and Streptococcus, were significantly higher in colostrum than in transitional milk and mature milk samples, and the other four most dominant bacterial taxa (Lactobacillus, two unclassified genera in the families Ruminococcaceae and Lachnospiraceae, and an unclassified genus in the order Clostridiales) demonstrated higher relative abundances in transitional and mature milk than in colostrum. Membrane transport, amino acid metabolism and carbohydrate metabolism were the most abundant functional categories in sow milk communities. Microbial network analysis based on the predominant genera revealed that the abundance of Helcococcus was negatively correlated with the abundances of most other genera in sow milk. Our results are the first to systematically indicate that the sow milk microbiota is a dynamic ecosystem in which changes mainly occur in the colostrum and remain generally stable throughout lactation.

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The intestinal microbiota is increasingly recognized as an important component of host health, metabolism and immunity. Early gut colonizers are pivotal in the establishment of microbial community structures affecting the health and growth performance of chickens. White Lohmann layer is a common commercial breed. Therefore, this breed was selected to study the pattern of changes of microbiota with age. In this study, the duodenum, caecum and colorectum contents of white Lohmann layer chickens from same environment control farm were collected and analyzed using 16S rRNA sequencing to explore the spatial and temporal variations in intestinal microbiota. The results showed that the diversity of the microbial community structure in the duodenum, caecum and colorectum increased with age and tended to be stable when the layer chickens reached 50 days of age and the distinct succession patterns of the intestinal microbiota between the duodenum and large intestine (caecum and colorectum). On day 0, the diversity of microbes in the duodenum was higher than that in the caecum and colorectum, but the compositions of intestinal microbes were relatively similar, with facultative anaerobic Proteobacteria as the main microbes. However, the relative abundance of facultative anaerobic bacteria (Escherichia) gradually decreased and was replaced by anaerobic bacteria (Bacteroides and Ruminococcaceae). By day 50, the structure of intestinal microbes had gradually become stable, and Lactobacillus was the dominant bacteria in the duodenum (41.1%). The compositions of dominant microbes in the caecum and colorectum were more complex, but there were certain similarities. Bacteroides, Odoribacter and Clostridiales vadin BB60 group were dominant. The results of this study provide evidence that time and spatial factors are important factors affecting the intestinal microbiota composition. This study provides new knowledge of the intestinal microbiota colonization pattern of layer chickens in early life to improve the intestinal health of layer chickens.

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An experiment was conducted to study the seasonal changes in the fatty acid profile of milk from yaks (Bos grunniens) when kept at altitudes of 3000 m above sea level (a.s.l.) and higher. Data and samples were collected in summer (July), autumn (September), winter (November) and spring (March) from ten lactating yaks (four in spring). The yaks grazed pastures adjacent to the farm building throughout the year. In spring only they received 0·6 kg crop by-products per day (dry matter basis). Fresh alpine grasses, available in summer and autumn, showed high concentrations of α-linolenic acid (46-51 g/100 g lipids) compared with the dry, yellow vegetation of winter and spring (16 g/100 g lipids). In autumn and summer, the milk fat had higher concentrations of polyunsaturated fatty acids than in winter. These polyunsaturated fatty acids were comprised of vaccenic acid, rumenic acid and α-linolenic acid, which are all considered beneficial to human health. The rare fatty acid, γ-linolenic acid, was also detected in yak milk, especially in the milk obtained in spring. The results suggest that yak milk, which is the most important basic food of the Tibetan herders, has the most favourable fatty acid profile when yaks grazed green pasture, which also corresponds to the period of highest milk production.

BackgroundHost genotype plays a crucial role in microbial composition of laying hens, which may lead to dissimilar odor gas production. The objective of this study was to investigate the relationship among layer breed, microbial structure and odor production.ResultsThirty Hy-Line Gray and thirty Lohmann Pink laying hens were used in this study to determine the impact of cecal microbial structure on odor production of laying hens. The hens were managed under the same husbandry and dietary regimes. Results of in vivo experiments showed a lower hydrogen sulfide (H2S) production from Hy-Line hens and a lower concentration of soluble sulfide (S2−) but a higher concentration of butyrate in the cecal content of the Hy-Line hens compared to Lohmann Pink hens (P < 0.05), which was consistent with the in vitro experiments (P < 0.05). However, ammonia (NH3) production was not different between genotypes (P > 0.05). Significant microbial structural differences existed between the two breed groups. The relative abundance of some butyrate producers (including Butyricicoccus, Butyricimonas and Roseburia) and sulfate-reducing bacteria (including Mailhella and Lawsonia) were found to be significantly correlated with odor production and were shown to be different in the 16S rRNA and PCR data between two breed groups. Furthermore, some bacterial metabolism pathways associated with energy extraction and carbohydrate utilization (oxidative phosphorylation, pyruvate metabolism, energy metabolism, two component system and secretion system) were overrepresented in the Hy-Line hens, while several amino acid metabolism-associated pathways (amino acid related enzymes, arginine and proline metabolism, and alanine-aspartate and glutamate metabolism) were more prevalent in the Lohmann hens.ConclusionThe results of this study suggest that genotype of laying hens influence cecal microbiota, which in turn modulates their odor production. Our study provides references for breeding and enteric manipulation for defined microbiota to reduce odor gas emission.

The gut microbiota plays a key role in host metabolic thermogenesis by activating UCP1 and increasing the browning process of white adipose tissue (WAT), especially in cold environments. However, the crosstalk between the gut microbiota and the host, which lacks functional UCP1, making them susceptible to cold stress, has rarely been illustrated. We used male piglets as a model to evaluate the host response to cold stress via the gut microbiota (four groups: room temperature group, n = 5; cold stress group, n = 5; cold stress group with antibiotics, n = 5; room temperature group with antibiotics, n = 3). We found that host thermogenesis and insulin resistance increased the levels of serum metabolites such as glycocholic acid (GCA) and glycochenodeoxycholate acid (GCDCA) and altered the compositions and functions of the cecal microbiota under cold stress. The gut microbiota was characterized by increased levels of Ruminococcaceae, Prevotellaceae, and Muribaculaceae under cold stress. We found that piglets subjected to cold stress had increased expression of genes related to bile acid and short-chain fatty acid (SCFA) metabolism in their liver and fat lipolysis genes in their fat. In addition, the fat lipolysis genes CLPS, PNLIPRP1, CPT1B, and UCP3 were significantly increased in the fat of piglets under cold stress. However, the use of antibiotics showed a weakened or strengthened cold tolerance phenotype, indicating that the gut microbiota plays important role in host thermogenesis. Our results demonstrate that the gut microbiota-blood-liver and fat axis may regulate thermogenesis during cold acclimation in piglets.