Arginine, a semi-essential functional amino acid, has been found to promote the synthesis of casein in mammary epithelial cells to some extent. Data from mouse indicated that microRNA (miRNA) are important in regulating the development of mammary gland and milk protein synthesis. Whether there are potential links among arginine, miRNA and casein synthesis in bovine mammary gland is uncertain. The objective of the present work was to detect the effects of arginine supplementation on the expression of miRNA associated with casein synthesis in mammary tissue and mammary epithelial cells (BMEC). The first study with bovine mammary epithelial cells (BMEC) focused on screening for miRNA candidates associated with the regulation of casein production by arginine. The BMEC were cultured with three different media, containing 0, 1.6 and 3.2 mM arginine, for 24 h. The expression of candidate miRNA was evaluated. Subsequently, in an in vivo study, 6 Chinese Holstein dairy cows with similar BW (mean ± SE) (512.0 ± 19.6 kg), parity (3), BCS (4.0) and DIM (190 ± 10.3 d) were randomly assigned to three experimental groups. The experimental cows received an infusion of casein, arginine (casein plus double the concentration of arginine in casein), and alanine (casein plus alanine, i.e., iso-nitrogenous to the arginine group) in a replicated 3 × 3 Latin square design with 22 d for each period (7 d for infusion and 15 d for washout). Mammary gland biopsies were obtained from each cow at the end of each infusion period. Results of the in vitro study showed differences between experimental groups and the control group for the expression of nine miRNA: miR-743a, miR-543, miR-101a, miR-760-3p, miR-1954, miR-712, miR-574-5p, miR-468 and miR-875-3p. The in vivo study showed that arginine infusion promoted milk protein content, casein yield and the expression of CSN1S1 and CSN1S2. Furthermore, the expression of miR-743a, miR-543, miR-101a, miR-760-3p, miR-1954, and miR-712 was also greater in response to arginine injection compared with the control or alanine group. Overall, results both in vivo and in vitro revealed that arginine might partly influence casein yield by altering the expression of 6 miRNAs (miR-743a, miR-543, miR-101a, miR-760-3p, miR-1954, and miR-712).

This study was designed to determine the effects of dietary arginine on development and proliferation in rat mammary tissue through changes in miRNA profiles. Twelve pregnant Wistar rats were allocated randomly to two groups. A basal diet containing arginine or the control diet containing glutamate on an equal nitrogen basis as the arginine supplemented diet were used. The experiment included a pre-experimental period of four days before parturition and an experimental period of 17 days after parturition. Mammary tissue was collected for histology, RNA extraction and high-throughput sequencing analysis. The greater mammary acinar area indicated that arginine supplementation enhanced mammary tissue development (p < 0.01). MicroRNA profiling indicated that seven miRNA (miR-206-3p, miR-133a-5p, miR-133b-3p, miR-1-3p, miR-133a-3p, miR-1b and miR-486) were differentially expressed in response to Arginine when compared with the glutamate-based control group. In silico gene ontology enrichment and KEGG pathway analysis revealed between 240 and 535 putative target genes among the miRNA. Further verification by qPCR revealed concordance with the differential expression from the sequencing results: 17 of 28 target genes were differentially expressed (15 were highly expressed in arginine and 2 in control) and 11 target genes did not have significant difference in expression. In conclusion, our study suggests that arginine may potentially regulate the development of rat mammary glands through regulating miRNAs.

The hygiene hypothesis has been advanced as a potential explanation for the increasingly high levels of atopy and allergic disease in the general human population. In an effort to conduct a more detailed study of the link between immune activity and the hygiene hypothesis, Meishan pigs raised under normal captivity (NC) or arch soil free-range (ASF) conditions were selected as an experimental model system. Cytokine levels were found to differ significantly between these two groups consistent with a difference in cellular immune status. Integrated transcriptomic and metabolomic profiling of duodenal tissue samples from Meishan pigs were then performed, leading to the identification of differentially expressed genes (DEGs), differentially abundant metabolites (DAMs), and key pathways that were able to distinguish the NC and ASF groups. This approach led to the identification of 1,113 DEGs, as well as 577 and 372 DAMs in positive and negative ion modes, respectively. When an interaction network incorporating DEGs and metabolites associated with immune responsivity was constructed, it included factors such as 9-cis-Retinoic acid, (9Z,11E)-(13S)-13-Hydroxyoctadeca-9,11-dienoic acid and (10E,12Z)-(9S)-9-Hydroxyoctadeca-10,12-dienoic acid. Functional enrichment analyses confirmed that identified DEGs and DAMs were associated with immune-related pathways including the intestinal IgA production and PPAR signaling pathways. Together, these results offer new insight into the roles that particular genes and metabolites enriched in response to environmental stressors in free-range Meishan pigs may play in the regulation of cellular immunity, thus offering a foundation for future efforts to better understand the immunological mechanisms underlying the hygiene hypothesis.

Alterations in microbiota, transcript and metabolites are critical to intestinal homeostasis and host health. This study used a combination of 16s rRNA, transcriptome sequencing and liquid chromatography–mass spectrometry to investigate intestinal microbiota, genes and metabolic profiles in the ileum of Hu sheep fed broccoli extract. Here, we randomly allocated 14 Hu sheep to two diets: a basal diet without any supplementation (NC) and a basal diet supplemented with 200 mg/kg broccoli tail (BT). After 60 days of treatment, blood and jejunal samples were collected for serum biochemical indicators and multi-omics analysis. In this study, the extract of broccoli tails had a significant effect on the serum biochemical indicators, including white blood cells, red blood cells, mean corpuscular volume, mean corpuscular hemoglobin concentration, mean platelet volume, triglycerides and total protein in Hu sheep (p < 0.05). Transcriptomic analysis showed that the 672 differentially expressed genes between the NC and BT groups were primarily enriched in linoleic acid metabolism, steroid hormone biosynthesis, and cholesterol metabolism. Metabolomics analysis using Kyoto Encyclopedia of Genes and Genomes enrichment showed that the 41 differentially abundant metabolites were mainly enriched in bile secretion, vitamin B6 metabolism, and the mTOR signaling pathway. 16S rRNA sequencing results indicated that the extract of broccoli tails increased the relative abundance of Peptostreptococcaceae and decreased the relative abundance of Lachnospiraceae, Lachnospirales, and Bacteroidaceae. Integrated transcriptome, metabolome, and microbiome analysis showed that the gut microbiota and host transcriptomic changes may participate in systemic metabolic regulation by modulating amino acid metabolism, lipid signal transduction, nucleotide metabolism, and vitamin B6-related metabolic pathways. These findings demonstrate that the extract of broccoli tails modulates intestinal gene expression, systemic metabolism, and gut microbial ecology in Hu sheep, providing new insights into the utilization of agricultural byproducts as a functional feed supplement for ruminants.