Breast cancer is a heterogeneous disease with increasing incidence and mortality and represents one of the most common cancer types worldwide. Low-density lipoprotein (LDL) is a complex particle composed of several proteins and lipids, which carries cholesterol into peripheral tissues and also affects the metabolism of fatty acids. Recent reports have indicated an emerging role of LDL in breast cancer, affecting cell proliferation and migration, thereby facilitating disease progression. However, controversy still exists among distinct types of breast cancer that can be affected by LDL. Classical therapeutic approaches, such as radiotherapy, chemotherapy, and lipid-lowering drugs were also reported as affecting LDL metabolism and content in breast cancer patients. Therefore, in this review we summarized and discussed the role of LDL in the development and treatment of breast cancer.

Leucine and isoleucine possess antioxidative and anti‐inflammatory properties. However, their underlying protective mechanisms against oxidative damage remain unknown. Therefore, in this study, the protective mechanism of leucine and isoleucine against H₂O₂‐induced oxidative damage in a bovine mammary epithelial cell lines (MAC‐T cells) were investigated. Briefly, MAC‐T cells exposed or free to H₂O₂ were incubated with different combinations of leucine and isoleucine. The cellular relative proliferation rate and viability, oxidative stress indicators, and inflammatory factors were determined by specific commercial kits. The genes related to barrier functions was measured by real‐time quantitative PCR. The protein expression differences were explored by 4D label‐free quantitative proteomic analyses and validated by parallel reaction monitoring. The results revealed that leucine and isoleucine increased cell proliferation, total antioxidant status (TAS), and the relative mRNA expression of occludin, as well as decreased malondialdehyde (MDA), total oxidant status (TOS)/TAS, IL‐6, IL‐1β, and TOS. When leucine and isoleucine were combined, MDA, TOS/TAS, and the relative mRNA expression levels of claudin‐1, occludin, and zonula occludens‐1 increased when compared to leucine or isoleucine alone. Proteomics analyses revealed that leucine significantly upregulated the propanoate metabolism; valine, leucine, and isoleucine degradation; and thermogenesis pathways, whereas isoleucine significantly upregulated the peroxisome and propanoate metabolism pathways. In conclusion, leucine protected MAC‐T cells from H₂O₂‐induced oxidative stress by generating more ATP to supplement energy demands, and isoleucine improved the deficit in peroxisome transport and promoted acetyl‐CoA production. The findings of this study enhance our understanding of the protective mechanisms of leucine and isoleucine against oxidative damage.

Background: Silage is achieved by anaerobic fermentation of lactic acid bacteria. However, harvest stage andLactiplantibacillus plantarum(L. plantarum) content affect the changes of microbial community in silage, which play an important role in silage quality and mycotoxin levels. The current study evaluated the effects exerted by the application ofL. plantarumon fermentation, mycotoxins and bacterial community of whole-crop corn silage at different harvest stages. The fresh whole plant corn from the same area was harvested during the milk stage and the dough stage, following which from each harvest stage was subjected to fourL. plantarumtreatments: 0 cfu/g; 1 × 10⁶ cfu/g; 1 × 10⁷ cfu/g; and 1 × 10⁸ cfu/g in a 2 × 4 factorial experimental design. Samples were collected on days 0, 3, 7, 21 and 42. Subsequently, nutrition parameters, fermentation parameters, mycotoxin levels and bacterial community were determined.Results: Prolonging the harvest stage resulted in an increase in the levels of starch and dry matter as well as deoxynivalenol in corn silage. Addition of 1 × 10⁷ cfu/g and 1 × 10⁸ cfu/g ofL. plantarumapplied after 42 d of ensilage reduced dry matter loss, which significantly lowered deoxynivalenol concentration in corn silage at the dough stage (P < 0.01). The pH of corn silage decreased, whereas the lactic acid concentration increased after ensiling. The effects exerted by the interaction (harvest stage × dose ofL. plantarum) on pH on day 21 as well as on fermentation and lactic acid on days 21 and 42 were significant (P < 0.05). Addition of 1 × 10⁷ cfu/g ofL. plantarumat the dough stage significantly increased the relative abundance of Firmicutes while decreasing that of Bacteroidetes, compared to whenL. plantarumwas not added (P < 0.05).Conclusions: AddingL. plantarumimproved the fermentation quality and bacterial community of silage, which reduced part of mycotoxin content and relative abundance of harmful bacteria. In addition, addingL. plantarumin dough stage resulted in greater improvements to mycotoxin content and bacterial community.

Processing can affect milk properties and alter the composition of milk metabolites, which has corresponding effects on milk flavor and quality. It is quite important to study the safe quality control of milk processing. Therefore, the purpose of this study was to identify metabolites at different steps of ultra‐high‐temperature‐sterilized (UHT) milk processing using gas chromatography–mass spectrometry (GC–MS). These steps included raw milk, pasteurized milk (80°C for 15 s), semi‐finished milk (after pasteurizing, it was homogenized at 75°C with pressure of 250 bar), UHT milk (at 140°C for 10 s), and finished milk (homogenized UHT milk). A total of 66 metabolites were identified across all samples, including 30 metabolites in the chloroform layers of the milk samples and 41 metabolites in the water layers; 5 metabolites were found in both layers. The metabolites were primarily fatty acids, amino acids, sugars, and organic acids. For example, pasteurized and ultra‐high‐temperature‐sterilized kinds of milk had lactose contents similar to those of raw milk, with increases in saturated fatty acids such as hexadecanoic acid and octadecanoic acid. Additionally, these findings indicated that these methods of processing can affect the contents of some components of milk. Therefore, from the perspective of milk's nutritional value and consumer health, the excessive heating of dairy products should be avoided and the milk heat treatment process should be standardized from the source.

This study aimed to investigate the effects of prepartum body condition score (BCS) on the milk yield, lipid metabolism, and oxidative status of Holstein cows. A total of 112 multiparous Holstein cows were divided into 4 groups according to the BCS at 21 days before calving: medium BCS (3.0~3.25, MBCS), high BCS (3.5~3.75, HBCS), higher BCS (4.0~4.25, HerBCS), and highest BCS (4.5~5.0, HestBCS). Blood samples were collected on 21, 14, and 7 days before calving (precalving), on the calving day (calving), and on 7, 14, and 21 days after calving (postcalving). The indices of lipid metabolism and oxidative status were analyzed using bovine-specific ELISA kit. Colostrum were taken after calving and analyzed by a refractometer and milk analyzer. The individual milk yield was recorded every 3 days. The density and levels of immune globulin and lactoprotein of colostrum from Holstein cows in the HestBCS group were the highest (p<0.05). These animals not only had the highest (p<0.05) levels of serum non-esterified fatty acids and beta-hydroxybutyrate, but also had the highest (p<0.05) levels of malondialdehyde, superoxide dismutase, catalase, vitamin A, and vitamin E. In addition, greater (p<0.05) BCS loss was observed in the HestBCS cows. This study demonstrates that the milk yield, lipid metabolism, and oxidative status of Holstein cows are related to prepartum BCS and BCS loss during the transition period. HestBCS cows are more sensitive to oxidative stress and suffer greater loss of BCS after calving, whereas the MBCS animals had better milk yield performance.

This study evaluated the effects of antimicrobial peptide (AMP) and tributyrin (TB) on dairy calves in terms of growth performance, immunity, oxidative stress, and intestinal microflora. A total of 40 female calves were divided into four treatment groups (n = 10): basal diet +0.015% essential oil, basal diet +0.03% AMP, basal diet +0.15% TB, and basal diet +0.03% AMP + 0.15% TB. AMP and TB supplementation increased the average daily gain (ADG) and weaning weight, while reducing diarrhea occurrence. Additionally, AMP and TB supplementation reduced the levels of reactive oxygen species (ROS) and malonaldehyde (MDA), while increasing superoxide dismutase (SOD) levels and serum immunoglobulin M (IgM) levels. However, the combined use of AMP and TB did not significantly affect the average daily feed intake, ADG, weaning weight, or diarrhea incidence but decreased ROS levels, while increasing SOD levels as well as MDA and IgM levels. Moreover, AMP and TG supplementation increased the relative abundance of several beneficial fiber‐ and mucin‐degrading bacteria in the gut, in contrast to combined AMP and TB supplementation. The 16S rRNA results showed that AMP supplementation significantly increased the relative abundance of Rikenellaceae_RC9_gut_group, Ruminococcaceae_UCG‐014 and [Eubacterium]_coprostanoligenes group (p < .01), and significantly decreased the relative abundance of Ruminococcaceae_UCG‐005 and Christensenellaceae_R‐7_group (p < .01). The TB supplementation significantly increased the abundances of Rikenellaceae_RC9_gut_group and Ruminococcaceae_UCG‐005 (p < .01), and significantly decreased the relative abundances of Ruminococcaceae_UCG‐014, [Eubacterium]_coprostanoligenes group and Christensenellaceae_R‐7_group (p < .01). The combined use of AMP and TB significantly increased the relative abundance of Rikenellaceae_RC9_gut_group and Bacteroides (p < .01), and significantly decreased the relative abundance of Ruminococcaceae_UCG‐014, [Eubacterium]_coprostanoligenes group and Christensenellaceae_R‐7_group (p < .01). In summary, diets supplemented with either AMP or TB improved the intestinal microflora, growth performance, and health of weaned calves, but combined use was detrimental to calf performance.