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BackgroundThe early weaning (EW) technology is an efficient method to improve the economic value of dairy ewes and satisfy the nutritional requirement of lambs which due to multiple fetuses or insufficient milk production of ewes. However, the affection of EW for rumen microflora is needed to evaluation because of the rumen microflora at early life would affect the health of host at whole life. In this study, the rumen microflora of dairy sheep with different EW time (D7, D15 and D25) were analyzed through 16s rDNA sequencing at D90. ResultsThe results showed that the application of EW did not affect the development of rumen. The species richness of the EW25 group was higher than EW7 and EW15 groups, while there was no significant difference in the abundance of microbial species between the CON and EW groups. At the phylum level, Firmicutes, Bacteroidetes, Fibrobacteres, Spirochaetes, Proteobacteria and Actinobacteria were the most dominant phyla in all the samples. At tenricutes level, the relative abundance of EW7 group was significantly higher than other three groups (p<0.05). The spearman correlation coefficient analysis showed that pH was positively correlated with Rikenellaceae_RC9, Succiniclasticum, F082_unclassified, etc. (p<0.05), and negatively correlated with Ruminococcaceae_UCG-014, Succiniclasticum, Selenomonas, etc. (p<0.05). The content of MCP was positively correlated with CAG-352 and Ruminococcus_2 (p<0.05). The width of rumen papilla was negatively correlated with non-classifiable bacteria (p<0.05). The thickness of rumen muscle layer was positively correlated with Sharpea (p<0.05). ConclusionsIn summary, the EW of dairy lambs does not affect the development of rumen at early life. The rumen bacterial diversity showed some differences between different EW days of age but no obvious effect, which could be a reference for dairy lamb’s EW time selection.

Lactic acid bacteria (LAB) produce various bioactive secondary metabolites (SMs), which endow LAB with a protective role for the host. However, the biosynthetic potentials of LAB-derived SMs remain elusive, particularly in their diversity, abundance, and distribution in the human microbiome. To gain an insight into the biosynthetic capacity of LAB, we analyzed the biosynthetic gene clusters (BGCs) from 31,977 LAB genomes and 748 human microbiome metagenomes, identifying 130,051 BGCs. The found BGCs were clustered into 2,849 gene cluster families (GCFs), most of which are species-specific, niche-specific, and uncharacterized yet. We found that most LAB BGCs encoded bacteriocins with pervasive antagonistic activities predicted by machine learning models, potentially playing protective roles in the human microbiome. Class II bacteriocins, the most abundant LAB SMs, are particularly enriched and predominant in vaginal microbiomes. Together with experimental validation, our metagenomic and metatranscriptomic analysis showed that class II bacteriocins with antagonistic potential might regulate microbial communities in the vagina, thereby contributing to homeostasis. These discoveries of the diverse and prevalent antagonistic SMs are expected to stimulate the mechanism study of LABs' protective roles in the host and highlight the potential of LAB as a new source of antibacterial SMs.

Appropriate early weaning (EW) technology can maximize the value of maternal sheep production without impact the normal growth and development of lambs. However, there is no mature EW technology for dairy sheep lambs. This study aimed to establish an appropriate EW technology for the crossbreed offspring of Dairy Meade (DM) sheep and Small-tailed Han (STH) sheep. The male lambs with similar birth weight were separated as four groups: three experimental groups (EW, n=6 of each group) of 7, 15 and 25D weaning after birth which using restricted milk replacer (MR) and the control group (CON, n=8) which artificially-reared with breast milk. The results showed that there was no significant difference in growth performance among each group at D90. In terms of organ weight, except the heart weight EW7 was higher than CON (p < 0.05), there was no significant difference between others (p > 0.05). The routine analysis of blood showed that there was no significant difference in major components between EW and CON groups. Histological analysis of digestive system showed that there was no significant difference between EW groups and CON except the rumen papillae width of EW25. The results of rumen fermentation parameters showed that there was no significant difference in pH and microbial proteins (MCP) content between EW groups and CON. In total, Different weaning time did not significantly affect the growth and development of dairy sheep lambs. Early weaning at D7 is a better strategy for the improvement of financial value of maternal sheep.