Ubiquitination modifications permit the degradation of labelled target proteins with the assistance of proteasomes and lysosomes, which is the main protein degradation pathway in eukaryotic cells. Polyubiquitination modifications of proteins can also affect their functions. De-ubiquitinating enzymes reverse the process of ubiquitination via cleavage of the ubiquitin molecule, which is known as a de-ubiquitination. It was demonstrated that ubiquitination and de-ubiquitination play key regulatory roles in fatty acid transport, de novo synthesis, and desaturation in dairy mammary epithelial cells. In addition, natural plant extracts, such as stigmasterol, promote milk fat synthesis in epithelial cells via the ubiquitination pathway. This paper reviews the current research on ubiquitination and de-ubiquitination in dairy milk fat production, with a view to providing a reference for subsequent research on milk fat and exploring new directions for the improvement of milk quality.

The nutritional value of goat milk is determined by the composition of its fatty acids, with particular importance placed on the role of unsaturated fatty acids in promoting human health. CircRNAs have been known to affect fatty acid metabolism through different pathways. In this study, high-throughput sequencing was employed to construct expression profiles of mammary tissue harvested during the dry period and peak lactation stages of dairy goats. Differentially expressed circRNAs and mRNAs were screened, revealing significantly higher expression levels of circRNA-08436 and ELOVL6 during the peak lactation period compared with the dry period. Thus, circRNA-08436 and ELOVL6 were chosen for subsequent studies. The findings demonstrated that circRNA-08436 not only promotes the synthesis of triglyceride (TAG) and cholesterol in goat mammary epithelial cells (GMECs), but also increases the concentrations of saturated fatty acids in the cells. Through the utilization of software prediction, the dual luciferase reporter system, and qRT-PCR, it was observed that circRNA-08436 binds to miR-195, with its overexpression reducing the expression levels of miR-195 and inhibiting TAG synthesis. In addition, circRNA-08436 upregulated the expression levels of the miR-195 target gene ELOVL6. The data also revealed that YTHDC1 facilitated the transport of circRNA-08436 from the nucleus to the cytoplasm, while YTHDC2 in the cytoplasm functioned as a “reader” to identify and degrade circRNA-08436. Taken together, these findings contribute to a better understanding of the molecular regulation of fatty acid metabolism in the mammary glands of dairy goats, thus offering a sound theoretical basis for the production of high-quality goat milk.

Like other pentacyclic triterpenoids, oleanolic acid, a natural plant metabolite prevalent in plant peels, stems, and leaves, is regarded as a possible drug candidate. A growing number of studies have shown that oleanolic acid exhibits a variety of beneficial properties, including antiviral, anti-inflammatory, antioxidant, anticancer, and hepatoprotective effects. Additionally, the rapid advance of nanotechnology has dramatically improved oleanolic acid’s bioavailability and minimized its disadvantages, leading to unexpected changes in its pharmacological activity and use. Therefore, our aim was to review the progress of research on the distribution and biological properties of oleanolic acid in plants and to discuss new pharmaceutical approaches for oleanolic acid.

Lead and cadmium are prevalent heavy metal toxins that contaminate the natural environment through animal husbandry and agricultural and industrial activities. Exposing dairy cows to these pollutants can have detrimental effects on milk production and quality, leading to health problems and decreasing the animals’ production performance. Therefore, investigating the distribution of lead and cadmium content and assessing the pollution levels at dairy farms are of significant theoretical and practical significance. This study determined the spatial distribution and clustering of lead and cadmium by sampling soil and feces from dairy farms in Jiangsu, China. The data obtained, in conjunction with soil data from Jiangsu Province, were used to evaluate the extent of lead and cadmium pollution at these farms. The results indicate that lead pollution levels are relatively low, whereas cadmium pollution is moderate in multiple regions. Ultimately, this study contributes to the assessment of the risks associated with lead and cadmium in dairy farming production and supports the establishment of a sustainable animal husbandry system, serving as an effective reference for subsequent ecological health farming, disease prevention, and management.

Objective: There is a strong relationship between the content of beneficial fatty acids in milk and milk fat metabolic activity in the mammary gland. To improve milk quality, it is therefore necessary to study fatty acid metabolism in bovine mammary gland tissue. In adipose tissue, peroxisome proliferator-activated receptor gamma (PPARG), the core transcription factor, regulates the fatty acid metabolism gene network and determines fatty acid deposition. However, its regulatory effects on mammary gland fatty acid metabolism during lactation have rarely been reported.Methods: Transcriptome sequencing was performed during the prelactation period and the peak lactation period to examine mRNA expression. The significant upregulation of PPARG drew our attention and led us to conduct further research.Results: According to bioinformatics prediction, dual-luciferase reporter system detection, real-time quantitative reverse transcription polymerase chain reaction and Western blotting, miR-130a and miR-130b could directly target PPARG and inhibit its expression. Furthermore, triglyceride and oil red O staining proved that miR-130a and miR-130b inhibited milk fat metabolism in bovine mammary epithelial cells (BMECs), while PPARG promoted this metabolism. In addition, we also found that the coexpression of miR-130a and miR-130b significantly enhanced their ability to regulate milk fat metabolism.Conclusion: In conclusion, our findings indicated that miR-130a and miR-130b could target and repress PPARG and that they also have a functional superposition effect. miR-130a and miR-130b seem to synergistically regulate lipid catabolism via the control of PPARG in BMECs. In the long-term, these findings might be helpful in developing practical means to improve high-quality milk.

Objective: The objective of this study was to investigate the differences in fatty acid composition of milk from Holstein cows, Jersey cows, Saanen goats, and humans at different lactation period and to find possible milk that is more suitable as a base for infant milk powder.Methods: Human breast milk, Saanen milk, Holstein milk, and Jersey milk were collected at different lactation stages. Gas chromatography was used to determine the fatty acid composition of breast milk, Saanen goat's milk, Holstein cow's milk and Jersey cows at different stages of lactation. Pearson correlation analysis was used to analyze the correlation between different fatty acids.Results: The results show that the types and relative contents of fatty acids varied among the different varieties of milk. The main fatty acids in breast milk are palmitic acid, oleic acid, and linoleic acid, which oleic acid is the most abundant. Saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) differed between lactation stages, while polyunsaturated fatty acids (PUFAs) did not differ significantly. Cow's milk and goat's milk were mainly dominated by SFAs, and Chinese Holstein cow's milk had the highest SFA content (72.54%). Caprylic and capric acids in SFAs were the characteristic fatty acids of goat's milk, and their contents were significantly higher than those of breast milk and cow's milk (p<0.05). The ratio of SFA:MUFA:PUFA breast milk was 1.72:1.45:1, Saanen goat's milk was 14.47:6:1, Chinese Holstein cow's milk was 14.98:4.84:1, and Jersey cow's milk was 13.32:4.47:1.Conclusion: None of the ruminant milk has the same proportion of fatty acids as breast milk, so none of them can completely replace breast milk. From the perspective of fatty acids, it is a better choice to choose Saanen goat milk or Jersey milk as a base and then add other ingredients to form infant milk powder.