Sodium Butyrate Ameliorates High-Concentrate Diet-Induced Inflammation in the Rumen Epithelium of Dairy Goats

Quercetin alleviates LPS/iE-DAP-induced liver injury by suppressing ferroptosis via regulating ferritinophagy and intracellular iron efflux

Ruminal dysbiosis-induced liver injury is prevalent in dairy cows, yet its underlying mechanisms remain incompletely understood. Ferroptosis, a newly identified form of programmed cell death distinct from apoptosis and necrosis, has been implicated in various liver diseases by emerging studies. In the present study, lipopolysaccharide (LPS) and γ-D-glutamyl-meso-diaminopimelic acid (iE-DAP) were employed to establish in vitro and in vivo models of liver injury using bovine hepatocytes and mice, respectively. It was observed that noncytotoxic iE-DAP alone did not influence lipid peroxidation or GPX4, but exacerbated LPS-induced ferroptosis and hepatocyte injury. Notably, co-treatment with LPS and iE-DAP (LPS/iE-DAP)-induced hepatocyte injury was mitigated by intervention with the ferroptosis inhibitor ferrostatin-1 (Fer-1). Mechanistically, the activated IL-6/STAT3 signaling pathway was found to mediate LPS/iE-DAP-induced ferroptosis. Suppression of IL-6/STAT3, either through IL6 and STAT3 knockdown or pharmacological intervention, reduced Fe2+ accumulation and alleviated ferroptotic cell death. Further investigations identified that IL-6/STAT3 signaling enhanced ferritinophagy and impaired iron export. Either disrupting ferritinophagy by knocking down NCOA4 or restoring iron export via HAMP knockdown relieved intracellular iron overload and inhibited ferroptosis. Specifically, LPS/iE-DAP treatment increased the interaction between hepcidin and ferroportin, promoting ferroportin ubiquitination and degradation, thereby blocking iron efflux. Furthermore, we provided several evidence to prove that quercetin pretreatment alleviated LPS/iE-DAP-induced ferroptosis and liver injury by decreasing hepatic iron accumulation via targeting the IL-6/STAT3 signaling in vitro and in vivo, effects reversed by the addition of recombinant bovine IL-6. Based on these findings, we concluded that LPS/iE-DAP-induced liver injury by triggering ferroptosis through regulating IL-6/STAT3/ferritinophagy-dependent iron release and IL-6/STAT3/hepcidin/ferroportin-dependent iron export, while quercetin could alleviate this liver injury by inhibiting ferroptosis via IL-6/STAT3 signaling pathway. This study provides novel insights into the mechanisms whereby ruminal dysbiosis induces liver injury and presents a prospective solution for ruminal dysbiosis-induced liver injury.

Butyrate Supplementation Improves Intestinal Health and Growth Performance in Livestock: A Review

Butyrate supplementation has gained considerable attention for its potential benefits in livestock, particularly concerning intestinal health and growth performance. This review synthesizes recent research on the diverse roles of butyrate, across various livestock species. As a short-chain fatty acid, butyrate is known for enhancing intestinal development, improving immune function, and modulating microbial diversity. Studies indicate that butyrate supports gut barrier integrity, reduces inflammation, and optimizes feed efficiency, especially during the critical weaning and post-weaning periods in calves, piglets, and lambs. Supplementation with butyrate in livestock has been shown to increase average daily gain (ADG), improve gut microbiota balance, promote growth, enhance gut health, boost antioxidant capacity, and reduce diarrhea. Additionally, butyrate plays a role in the epigenetic regulation of gene expression through histone acetylation, influencing tissue development and immune modulation. Its anti-inflammatory and antioxidant effects have been demonstrated across various species, positioning butyrate as a potential therapeutic agent in animal nutrition. This review suggests that optimizing butyrate supplementation strategies to meet the specific needs of each species may yield additional benefits, establishing butyrate as an important dietary additive for enhancing growth performance and health in livestock.

Changes in the rumen development, rumen fermentation, and rumen microbiota community in weaned calves during steviol glycosides treatment

Early weaning leads to weaning stress in calves, which hinders healthy growth and development. As an excellent sweetener applied in food, steviol glycosides (STE) has also been shown to exhibit positive biological activity in monogastric animals. Therefore, this study aimed to evaluate the impact of incorporating STE as a dietary supplement on rumen development, fermentation, and microbiota of rumen in weaned calves. This study selected 24 healthy Holstein bull calves and randomly allocated them into two groups (CON and STE). The results indicated that supplementation STE group improved rumen development in weaned calves, as demonstrated by a marked increase in the weight of the rumen, as well as the length and surface area of the rumen papilla. Compared with the CON group, the concentrations of total volatile fatty acids (TVFA), propionate, butyrate, and valerate were higher in the STE group. Moreover, STE treatment increased the relative abundance of Firmicutes and Actinobacteria at the phylum level. At the genus level, the STE group showed a significantly increased relative abundance of Succiniclasticum, Lachnospiraceae_NK3A20_group, and Olsenella, and a decreased relative abundance of Acinetobacter compared to the CON group. Pusillimonas, Lachnospiraceae_NK3A20_group, Olsenella, and Succiniclasticum were significantly enriched in rumen chyme after supplementation with STE, as demonstrated by LEfSe analysis. Overall, our findings revealed that rumen bacterial communities altered in response to the dietary supplementation with STE, and some bacterial taxa in these communities may have positive effects on rumen development during this period.

The Impact of Different Dietary Ratios of Soluble Carbohydrate-to-Neutral Detergent Fiber on Rumen Barrier Function and Inflammation in Dumont Lambs

Appropriate soluble carbohydrate (SCHO)-to-NDF ratios in the diet are essential for rumen health. The effects of different SCHO-to-NDF ratios (1.0, 1.5, and 2.0) on rumen barrier function and inflammation in Dumont lambs (n = 18, 6 replicates per treatment) was investigated. The SCHO:NDF ratio was altered by replacing the forage (Leynus chinensis) with corn grain. With an increase in the proportion of SCHO, the final body weight (FBW), average daily gain (ADG), soluble carbohydrate intake (SCHOI), and LPS level increased; and the neutral detergent fiber intake (NDFI), ruminal papillae height, papillae area, and pH decreased (p < 0.05, plin < 0.05). The medium CHO:NDF group had increased claudin-1 mRNA (p < 0.05, plin = 0.005, pquad = 0.003) and protein (p < 0.05, pquad < 0.001) levels; the high CHO:NDF group had increased occludin mRNA and protein (p < 0.05, plin = 0.001) levels. The level of the anti-inflammatory cytokine IL-10 was significantly greater in the medium CHO:NDF group than in the high CHO:NDF group (p < 0.05, pquad < 0.001). With an increase in the ratio of SCHO, the mRNA level and concentration of the proinflammatory cytokines IL-1β, IL-6, and TNF-α linearly increased (p < 0.05, plin < 0.05), and those in the high CHO:NDF group were significantly greater than those in the low CHO:NDF group. The levels of phosphorylated p65 (plin = 0.003), IκB-α (plin < 0.001), and JNK (plin = 0.001) increased linearly, and those in the high CHO:NDF group were significantly greater than those in the other two groups (p < 0.05). Therefore, when the SCHO-to-NDF ratio was increased to 1.5, the rumen epithelium was not affected, but when the ratio was increased to 2.0, NF-κB and MAPK were activated in the rumen epithelium, leading to impaired barrier function and inflammation. The suitable NFC:NDF ratio for the short-term fattening of Dumont lambs was found to be 1.50.

Multi-Omics Reveals the Impact of Exogenous Short-Chain Fatty Acid Infusion on Rumen Homeostasis: Insights into Crosstalk between the Microbiome and the Epithelium in a Goat Model

Emerging data have underscored the significance of exogenous supplementation of butyrate in the regulation of rumen development and homeostasis. However, the effects of other short-chain fatty acids (SCFAs), such as acetate or propionate, has received comparatively less attention, and the consequences of extensive exogenous SCFA infusion remain largely unknown. In our study, we conducted a comprehensive investigation by infusion of three SCFAs to examine their respective roles in regulating the rumen microbiome, metabolism, and epithelium homeostasis. Data demonstrated that the infusion of sodium acetate (SA) increased rumen index while also promoting SCFA production and absorption through the upregulation of SCFA synthetic enzymes and the mRNA expression of SLC9A1 gene. Moreover, both SA and sodium propionate infusion resulted in an enhanced total antioxidant capacity, an increased concentration of occludin, and higher abundances of specific rumen bacteria, such as "Candidatus Saccharimonas," Christensenellaceae R-7, Butyrivibrio, Rikenellaceae RC9 gut, and Alloprevotella. In addition, sodium butyrate (SB) infusion exhibited positive effects by increasing the width of rumen papilla and the thickness of the stratum basale. SB infusion further enhanced antioxidant capacity and barrier function facilitated by cross talk with Monoglobus and Incertae Sedis. Furthermore, metabolome and transcriptome data revealed distinct metabolic patterns in rumen contents and epithelium, with a particular impact on amino acid and fatty acid metabolism processes. In conclusion, our data provided novel insights into the regulator effects of extensive infusion of the three major SCFAs on rumen fermentation patterns, antioxidant capacity, rumen barrier function, and rumen papilla development, all achieved without inducing rumen epithelial inflammation. IMPORTANCE The consequences of massive exogenous supplementation of SCFAs on rumen microbial fermentation and rumen epithelium health remain an area that requires further exploration. In our study, we sought to investigate the specific impact of administering high doses of exogenous acetate, propionate, and butyrate on rumen homeostasis, with a particular focus on understanding the interaction between the rumen microbiome and epithelium. Importantly, our findings indicated that the massive infusion of these SCFAs did not induce rumen inflammation. Instead, we observed enhancements in antioxidant capacity, strengthening of rumen barrier function, and promotion of rumen papilla development, which were facilitated through interactions with specific rumen bacteria. By addressing existing knowledge gaps and offering critical insights into the regulation of rumen health through SCFA supplementation, our study holds significant implications for enhancing the well-being and productivity of ruminant animals.

A high-concentrate diet induces mitochondrial dysfunction by activating the MAPK signaling pathway in the mammary gland of dairy cows

Subacute rumen acidosis can lead to mastitis in dairy cows. Mitochondrial dysfunction is closely related to the inflammatory response. This experiment was conducted to investigate the effects of a high-concentrate diet on mammary gland inflammation and mitochondrial damage in dairy cows. Twelve Holstein dairy cows in mid-lactation were randomly divided into 2 groups and fed a 40% concentrate (low concentrate, LC) diet or a 60% concentrate (high concentrate, HC) diet. Cows were fed individually, and the experiment lasted for 3 wk. After the experiment, mammary gland tissue, blood, and rumen fluid were collected. Compared with the LC diet, the HC diet significantly decreased rumen pH; the pH was <5.6 for more than 3 h. The HC diet also increased the concentration of LPS in the blood (7.17 ± 1.25 µg/mL vs. 12.12 ± 1.26 µg/mL), which indicated that feeding the HC diet successfully induced subacute rumen acidosis. The HC diet also increased the concentration of Ca2+ (34.80 ± 4.23 µg/g vs. 46.87 ± 7.24 µg/g) in the mammary gland and upregulated the expression of inflammatory factors IL-6 (1,128.31 ± 147.53 pg/g vs. 1,538.42 ± 241.38 pg/g), IL-1β (69.67 ± 5.86 pg/g vs. 90.13 ± 4.78 pg/g), and tumor necrosis factor-α (91.99 ± 10.43 pg/g vs. 131.75 ± 17.89 pg/g) in mammary venous blood. The HC diet also increased the activity of myeloperoxidase (0.41 ± 0.05 U/g vs. 0.71 ± 0.11 U/g) and decreased the content of ATP (0.47 ± 0.10 µg/mL vs. 0.32 ± 0.11 µg/mL) in the mammary gland. In addition, phosphorylation of JNK (1.00 ± 0.21 vs. 2.84 ± 0.75), ERK (1.00 ± 0.20 vs. 1.53 ± 0.31), and p38 (1.00 ± 0.13 vs. 1.47 ± 0.41) and protein expression of IL-6 (1.00 ± 0.22 vs. 2.21 ± 0.27) and IL-8 (1.00 ± 0.17 vs. 1.96 ± 0.26) were enhanced in cows of the HC group, indicating that the mitogen-activated protein kinase (MAPK) signaling pathway was activated. Compared with the LC diet, the HC diet reduced the protein expression of mitochondrial biogenesis-related proteins PGC-1α (1.00 ± 0.17 vs. 0.55 ± 0.12), NRF1 (1.00 ± 0.17 vs. 0.60 ± 0.10), TFAM (1.00 ± 0.10 vs. 0.73 ± 0.09), and SIRTI (1.00 ± 0.44 vs. 0.40 ± 0.10). The HC diet promoted mitochondrial fission and inhibited mitochondrial fusion by reducing protein expression of MFN1 (1.00 ± 0.31 vs. 0.49 ± 0.09), MFN2 (1.00 ± 0.19 vs. 0.69 ± 0.13), and OPA1 (1.00 ± 0.08 vs. 0.72 ± 0.07), and by increasing that of DRP1 (1.00 ± 0.09 vs. 1.39 ± 0.10), MFF (1.00 ± 0.15 vs. 1.89 ± 0.12), and TTC1/FIS1 (1.00 ± 0.08 vs. 1.76 ± 0.14), leading to mitochondrial dysfunction. The HC diet increased mitochondrial permeability by upregulating the protein expression of VDAC1 (1.00 ± 0.42 vs. 1.90 ± 0.44), ANT (1.00 ± 0.22 vs. 1.27 ± 0.17), and CYPD (1.00 ± 0.41 vs. 1.82 ± 0.43). Taken together, these results indicated that feeding the HC diet induced mitochondrial damage via the MAPK signaling pathway in the mammary gland of dairy cows.

Effects of a High-Concentrate Diet on the Blood Parameters and Liver Transcriptome of Goats

The objective of this study was to determine the effect of high-concentrate diets on the blood parameters and liver transcriptome of goats. Eighteen goats were allocated into three dietary treatments: the high level of concentrate (HC) group, the medium level of concentrate (MC) group, and the low level of concentrate (LC) group. The blood parameters and pathological damage of the gastrointestinal tract and liver tissues were measured. In hepatic portal vein blood, HC showed higher LPS, VFAs, and LA; in jugular vein blood, no significant differences in LPS, VFAs, and LA were recorded among groups (p > 0.05). Compared to the LC and MC groups, the HC group showed significantly increased interleukin (IL)-1β, IL-10, TNF-α, and diamine oxidase in jugular vein blood (p < 0.05). Liver transcriptome analysis discovered a total of 1269 differentially expressed genes (DEGs) among the three groups and most of them came from the HC vs. LC group. There were 333 DEGs up-regulated and 608 down-regulated in the HC group compared to the LC group. The gene ontology enrichment analysis showed that these DEGs were mainly focused on the regulation of triacylglycerol catabolism, lipoprotein particle remodeling, and cholesterol transport. The Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that the liver of the HC group enhanced the metabolism of nutrients such as VFAs through the activation of AMPK and other signaling pathways and enhanced the clearance and detoxification of LPS by activating the toll-like receptor signaling pathway. A high-concentrate diet (HCD) can significantly promote the digestion of nutrients; the liver enhances the adaptability of goats to an HCD by regulating the expression of genes involved in nutrient metabolism and toxin clearance.

Nutraceutical Effect of Resveratrol on the Mammary Gland: Focusing on the NF-κb /Nrf2 Signaling Pathways

The aim of this study is to evaluate the defensive role of resveratrol, which is antagonistic to the oxidative stress and inflammation that is prompted by LPS in mammary tissue of female mice. Thirty adult mice were distributed into three groups (n = 10) control (CON), lipopolysaccharides at 2.5 mg/kg (LPS), and lipopolysaccharides at 2.5 mg/kg with 2 mg/kg of resveratrol (RES + LPS). The treatments were applied for 15 consecutive days. Spectrophotometry was used to quantify ROS in the blood, and proinflammatory cytokines concentrations were determined through radioimmunoassay. NF-κB, Jnk, IL-1β, Erk, IL-6, Nrf2 and TNF-α were quantified by RT-qPCR, and Western blots were used to quantifyP65 and pP65 protein intensities. MDA production was considerably increased, and the activity of T-AOC declined in the LPS treatment in comparison with the CON group but was significantly reversed in the RES + LPS group. Proinflammatory cytokines production and the genes responsible for inflammation and oxidative stress also showed higher mRNA and pP65 protein intensity in the LPS group, while Nrf2 showed a remarkable decline in mRNA expression in the LPS versus the CON group. All these mRNA intensities were reversed in the RES + LPS group. There were no remarkable changes in P65 protein intensity observed between the CON, LPS, and RES + LPS groups. In conclusion, resveratrol acts as a protective agent to modulate cellular inflammation and oxidative stress caused by LPS in mammary tissue of female mice.

High concentrate diet induced inflammatory response and tight junction disruption in the mammary gland of dairy cows

This study aimed to investigate the effect and mechanism of a high concentrate (HC) diet on the inflammatory response and cellular tight junctions (TJs) in the mammary gland of dairy cows. Twelve lactating Holstein dairy cows were randomly assigned into low concentrate (LC) and HC groups (n = 6), which were fed with LC diet and HC diet respectively for 3 weeks. The HC diet lead to subacute ruminant acidosis with a rumen pH < 5.6 more than 3 h daily. The HC diet triggered an inflammatory response with increased levels of inflammatory cytokines in the lacteal vein, upregulated expression of inflammation-related genes, elevated activity of myeloperoxidase, and inflammatory cells infiltration in the mammary gland. Furthermore, the HC diet induced the activation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways with enhanced phosphorylation ratios of NF-κB P65, inhibitor of NF-κB (IκB), P38 and extracellular signal-regulated kinase 1/2 (ERK1/2) as well as decreased ratios of DNA methylation and chromatin compaction of genes coding for proinflammatory cytokines, which contributed to the upregulation of proinflammatory cytokine expression. The HC diet also destroyed the integrity of TJ with discontinuous and decreased expression levels of zonula occludens-1, Occludin, Claudin-4 and increased expression level of Claudin-1 in the mammary epithelial cells compared with LC group. Conclusively, the HC diet induced the activation of NF-κB and MAPK signaling pathways and epigenetic modifications, promoted the transcription of proinflammatory cytokines, and finally caused inflammatory response and TJ disruption in the mammary gland of dairy cows.

Sodium butyrate pretreatment mitigates lipopolysaccharide-induced inflammation through the TLR4/NF-κB signaling pathway in bovine embryo trachea cells

The present study investigated the anti-inflammatory effects and potential mechanisms of sodium butyrate (SB) in bovine embryo tracheal cells (EBTr) stimulated with lipopolysaccharide (LPS). EBTr were exposed to either 1 mmol/L SB for 18 h for the SB group (SB) or to 0.4 μg/mL LPS for 6 h for the LPS group (LPS). PBS was added to EBTr for a control group (CON). EBTr were pretreated with SB for 18 h followed by 6 h of LPS stimulation for the LSB group (LSB). Results showed that with LPS stimulation, the gene expression of TLR4, NF-κB, IL6, and IL8, as well as cytokine production of IL6 and TNF-α, were significantly increased compared with the CON group. In contrast, protein expression of IL10 was decreased. However, these inflammatory effects induced by LPS were reversed in the LSB group. Compared with the CON group, protein expression of TLR4, phospho-NF-κB p65, phospho-IκBα, and IL1α were increased in the LPS group and these were decreased in the LSB group. Similarly, increased nuclear translocation of phospho-NF-κB p65 in the LPS group was suppressed with SB pretreatment. In conclusion, SB can reduce inflammation induced by LPS in EBTr, and this positive effect is mediated through the TLR4 and NF-κB signaling pathway.

Different feeding strategies can affect growth performance and rumen functions in Gangba sheep as revealed by integrated transcriptome and microbiome analyses

Due to the harsh environment in the Tibetan Plateau, traditional grazing greatly limits the growth potential of local animals and causes severe ecosystem degradation. This is an urgent issue to be solved, which requires alternative strategies for grazing animals in the Tibetan alpine pastoral livestock systems. This study aimed to investigate the effects of different feeding strategies on growth performance and ruminal microbiota-host interactions in the local breed of sheep (Gangba sheep). Thirty 9-month old Gangba sheep (n = 10 per group) were assigned to natural grazing (G), semi-grazing with supplementation (T), and barn feeding (F) groups (supplementation of concentrate and oat hay) based on body weight. At the end of the experiment (75 d), all sheep were weighed, rumen fluid was obtained from six sheep per group, and ruminal epithelium was obtained from 3 sheep per group. The results showed that: (1) Compared with the G and T groups, the F group significantly increased dry matter intake, average daily gain, and feed conversion ratio of animals. Additionally, Gangba sheep in the F group had higher concentrations of ruminal short-chain volatile fatty acids (VFAs), especially propionate and butyrate (P <0.05) than sheep in the G and T groups. (2) The principal coordinates analysis indicated a significant difference in bacterial composition among different feed strategies. More specifically, the relative abundance of propionate (unidentified F082 and Succiniclasticum) and butyrate-producing (Eubacterium_coprostanoligenes_group) genera were also observed to be increased in the F group, in which unidentified F082 was identified as a differential biomarker among the three groups according to linear discriminant analysis effect size analysis. (3) The dynamics of the rumen epithelial transcriptome revealed that ECM-receptor interactions, focal adhesion, and PI3K-Akt signaling pathways, which are critical in mediating many aspects of cellular functions such as cell proliferation and motility, were upregulated in the F group. In conclusion, under harsh conditions in the Tibetan alpine meadow, barn feeding increased ruminal VFAs concentrations (especially propionate and butyrate), which stimulated gene expression related to cell proliferation in rumen epithelium, appearing to be superior to natural grazing and semi-grazing in gaining body weight of the local Gangba sheep.

Protective Roles of Sodium Butyrate in Lipopolysaccharide-Induced Bovine Ruminal Epithelial Cells by Activating G Protein-Coupled Receptors 41

This study aimed to evaluate whether sodium butyrate (SB) attenuates the ruminal response to LPS-stimulated inflammation by activating GPR41 in bovine rumen epithelial cells (BRECs). We examined the SB regulation of GPR41 and its impact on LPS-induced inflammation using GPR41 knockdown BRECs. The LPS-induced BRECs showed increases in the expression of genes related to pro-inflammation and decreases in the expression of genes related to tight junction proteins; these were attenuated by pretreatment with SB. Compared with that in LPS-stimulated BRECs, the ratio of phosphorylated NF-κB (p65 subunit) to NF-κB (p65 subunit) and the ratio of phosphorylated IκBα to IκBα were suppressed with SB pretreatment. The LSB group abated LPS-induced apoptosis and decreased the expression of Bax, Caspase 3, and Caspase 9 mRNA relative to the LPS group. In addition, the LSB group had a lower proportion of cells in the G0–G1 phase and a higher proportion of cells in the S phase than the LPS group. The mRNA expression of ACAT1 and BDH1 genes related to volatile fatty acid (VFA) metabolism were upregulated in the LSB group compared to those in LPS-induced BRECs. In addition, pretreatment with SB promoted the gene expression of GPR41 in the LPS-induced BRECs. Interestingly, SB pretreatment protected BRECs but not GPR41KD BRECs. Our results suggest that SB pretreatment protects against the changes in BRECs LPS-induced inflammatory response by activating GPR41.

Effects of dietary butyrate supplementation and oral nonsteroidal anti-inflammatory drug administration on serum inflammatory markers and productivity of dairy cows during the calving transition

Dairy cattle experience inflammation during the calving transition period, and butyrate and nonsteroidal anti-inflammatory drugs (NSAID) are expected to reduce the inflammation. Our objective was to evaluate the effects of dietary butyrate supplementation and oral NSAID administration on feed intake, serum inflammatory markers, plasma metabolites, and milk production of dairy cows during the calving transition period. Eighty-three Holstein cows were used in the experiment with a 2 × 2 factorial arrangement of treatments. The cows were blocked by parity and calving date, and randomly assigned to a dietary butyrate or control supplement, and NSAID or a placebo oral administration. Experimental diets were iso-energetic containing calcium butyrate at 1.42% of diet dry matter (DM) or the control supplement (1.04% commercial fat supplement and 0.38% calcium carbonate of diet DM). The close-up diets contained 13.3% starch and 42.4% neutral detergent fiber on a DM basis, and were fed from 28 d before expected calving date until calving. The postpartum diets contained 22.1% starch and 34.1% neutral detergent fiber on a DM basis and were fed from calving to 24 d after calving. Oral NSAID (1 mg of meloxicam/kg of body weight) or placebo (food dye) was administered 12 to 24 h after calving. Dietary butyrate supplementation and oral NSAID administration did not affect milk yield or postpartum serum concentrations of amyloid A and haptoglobin. However, butyrate-fed cows increased plasma fatty acid concentration on d -4 relative to calving (501 vs. 340 μEq/L) and tended to increase serum haptoglobin concentration (0.23 vs. 0.10 mg/mL). There was a supplement by drug interaction effect on plasma glucose concentration on d 4; in cows administered the placebo drug, butyrate supplementation decreased plasma glucose concentration compared with control-fed cows (62.8 vs. 70.1 mg/dL). Butyrate-fed cows tended to have lower milk crude protein yield compared with cows fed the control diet (1.21 vs. 1.27 kg/d). Dietary butyrate supplementation and oral NSAID administration did not have overall positive effects on production performance of dairy cows during the calving transition period.

The Rumen Microbiota Contributes to the Development of Mastitis in Dairy Cows

Mastitis, a highly prevalent disease in dairy cows, is commonly caused by local infection of the mammary gland. Our previous studies have suggested that the gut microbiota plays an important role in the development of mastitis in mice. However, the effects of rumen microbiota on bovine mastitis and the related mechanisms remain unclear. In this study, we assessed the effects and mechanisms of rumen microbiota on bovine mastitis based on the subacute rumen acidosis (SARA) model induced by feeding Holstein Frisian cows a high-concentrate diet for 8 weeks. Then, the inflammatory responses in the mammary gland and the bacterial communities of rumen fluid, feces, and milk were analyzed. The results showed that SARA induced mastitis symptoms in the mammary gland; activated a systemic inflammatory response; and increased the permeability of the blood-milk barrier, gut barrier, and rumen barrier. Further research showed that lipopolysaccharides (LPS), derived from the gut of SARA cows, translocated into the blood and accumulated in the mammary glands. Furthermore, the abundance of Stenotrophomonas was increased in the rumen of SARA cows, and mastitis was induced by oral administration of Stenotrophomonas in lactating mice. In conclusion, our findings suggested that mastitis is induced by exogenous pathogenic microorganisms as well as by endogenous pathogenic factors. Specifically, the elevated abundance of Stenotrophomonas in the rumen and LPS translocation from the rumen to the mammary gland were important endogenous factors that induced mastitis. Our study provides a foundation for novel therapeutic strategies that target the rumen microbiota in cow mastitis. IMPORTANCE Mastitis is a common and frequently occurring disease of humans and animals, especially in dairy farming, which has caused huge economic losses and brought harmful substance residues, drug-resistant bacteria, and other public health risks. The traditional viewpoint indicates that mastitis is mainly caused by exogenous pathogenic bacteria infecting the mammary gland. Our study found that the occurrence of mastitis was induced by the endogenous pathway. Evidence has shown that rumen-derived LPS enters the mammary gland through blood circulation, damaging the blood-milk barrier and then inducing inflammation of the mammary gland in cows. In addition, a higher abundance of Stenotrophomonas in the rumen was closely associated with the development of mastitis. This study provides a basis for novel therapeutic strategies that exploit the rumen microbiota against mastitis in cows.

Water extract of Ferula lehmanni Boiss. prevents high-fat diet-induced overweight and liver injury by modulating the intestinal microbiota in mice

Obesity, often accompanied by hepatic steatosis, has been associated with an increased risk of health complications such as fatty liver disease and certain cancers. Ferula lehmannii Boiss., a food and medicine homologue, has been used for centuries as a seasoning showing anti-bacterial and anti-oxidant effects on digestive discomfort. In the present study, we sought to investigate whether a short-term oral administration of water extract of Ferula lehmanni Boiss. (WEFL) could prevent high-fat diet (HFD)-induced abnormal weight gain and hepatic steatosis in mice and its underlying mechanisms. WEFL reduced HFD-increased body weight, liver injury markers and inflammatory cytokines (i.e. IL-6 and IL-1β), and inhibited the elevation of AMPKα, SREBP-1c and FAS in HFD. Moreover, WEFL reconstructed the gut microbiota composition by increasing the relative abundances of beneficial bacteria, e.g. Akkermansia spp., while decreasing Desulfovibrio spp. and so on, thereby reversing the detrimental effects of HFD in mice. Removal of the gut microbiota with antibiotics partially eliminated the hepatoprotective effects of WEFL. Notably, WEFL substantially promoted the levels of short-chain fatty acids, especially butyric acid. To clarify the functional components at play in WEFL, we used UPLC-MS/MS to comprehensively detect its substance composition and found it to be a collection of polyphenol-rich compounds. Together, our findings demonstrate that WEFL prevented HFD-induced obesity and liver injury through the hepatic-microbiota axis, and such health-promoting value might be explained by the enriched abundant polyphenols.

Sodium butyrate administration modulates the ruminal villus height, inflammation-related gene expression, and plasma hormones concentration in dry cows fed a high-fiber diet

The objectives of this study were to evaluate the effects of sodium butyrate on the ruminal villus morphology, mRNA expression associated with nutrient metabolism and inflammation in the ruminal epithelium, and plasma concentrations of metabolites and hormones in non-lactating cows fed a high-fiber diet. Four Holstein cows with a rumen cannula were assigned to two treatments in a crossover design. The treatments were ruminal administration of sodium butyrate premix or control premix before feeding to cows fed the same total mixed ration mainly composed of glass silage once a day. Sodium butyrate was provided at a butyrate dose of 0.04% per kg body weight. The control premix was made by replacing sodium-butyrate with wheat bran. The plasma β-hydroxybutyrate concentration increased 3 to 6 h after the butyrate premix administration but returned to a concentration similar to that of the control before feeding. After continuous administration, increases in the ruminal villus height and plasma concentration of glucagon-like peptide-2, and lower gene expression of TNF-α, IL-1β, and TLR-2 in the rumen epithelium were observed in cows supplied with the butyrate premix. These results showed that sodium butyrate affects rumen epithelial morphology and plasma concentrations of hormones even under a low fermentable diet.

Genome-Wide Identification of Reference Genes for Reverse-Transcription Quantitative PCR in Goat Rumen

Simple Summary

The rumen plays an essential role as a digestive organ and serves as the primary site of energy substrate absorption for the productive ruminants. Understanding gene expression profiles is necessary to explore the intrinsic regulatory mechanisms of rumen development in goats. The selection of suitable reference genes (RGs) was the primary assay before the real-time quantitative PCR (RT-qPCR). We identified sixteen genome-wide candidate RGs for normalization of gene expression assessments in goat rumen tissues. We demonstrate that the RGs selected (RPS4X and RPS6) were more stably expressed than the commonly used HKGs (ACTB and GAPDH) in goat rumen tissues, suggesting that the ribosomal protein gene family may be another source for the RG pool.

Abstract

As the largest chamber of the ruminant stomach, the rumen not only serves as the principal absorptive surface and nutrient transport pathway from the lumen into the animal, but also plays an important short-chain fatty acid (SCFA) metabolic role in addition to protective functions. Accurate characterization of the gene expression profiles of genes of interest is essential to the exploration of the intrinsic regulatory mechanisms of rumen development in goats. Thus, the selection of suitable reference genes (RGs) is an important prerequisite for real-time quantitative PCR (RT-qPCR). In the present study, 16 candidate RGs were identified from our previous transcriptome sequencing of caprine rumen tissues. The quantitative expressions of the candidate RGs were measured using the RT-qPCR method, and the expression stability of the RGs was assessed using the geNorm, NormFinder, and BestKeeper programs. GeNorm analysis showed that the M values were less than 0.5 for all the RGs except GAPT4, indicating that they were stably expressed in the rumen tissues throughout development. RPS4X and RPS6 were the two most stable RGs. Furthermore, the expressions of two randomly selected target genes (IGF1 and TOP2A), normalized by the selected most stable RGs (RPS4X and RPS6), were consistent with the results of RNA sequencing, while the use of GAPDH and ACTB as RGs resulted in altered profiles. Overall, RPS4X and RPS6 showed the highest expression stability and the lowest coefficients of variation, and could be used as the optimal reference combination for quantifying gene expression in rumen tissues via RT-qPCR analysis.

Investigating the Reciprocal Interrelationships among the Ruminal Microbiota, Metabolome, and Mastitis in Early Lactating Holstein Dairy Cows

Simple Summary

Dairy cow mastitis is an inflammatory disease often caused by bacterial infections. In the present study, we identified the ruminal microbial biomarkers and metabolites of mastitis in dairy cows. The investigation of the reciprocal interrelationships among the ruminal microbiota, metabolome, and mastitis revealed that short-chain fatty acid (SCFA)-producing microflora and the metabolites related to anti-inflammation and antibacterial activity were significantly higher in healthy cows than in those with mastitis. The identified potential species and metabolites might provide a novel perspective to assist in targeting the ruminal microbiota with preventive/therapeutic strategies against mastitis in the future.

Abstract

Mastitis in dairy cow significantly affects animal performance, ultimately reducing profitability. The reciprocal interrelationships among ruminal microbiota, metabolome, and mastitis combining early inflammatory factors (serum proinflammatory cytokines) in lactating dairy cows has not been explored, thus, this study evaluated these reciprocal interrelationships in early lactating Holstein dairy cows to identify potential microbial biomarkers and their relationship with ruminal metabolites. The ruminal fluid was sampled from 8 healthy and 8 mastitis cows for the microbiota and metabolite analyses. The critical ruminal microbial biomarkers and metabolites related to somatic cell counts (SCC) and serum proinflammatory cytokines were identified by the linear discriminant analysis effect size (LEfSe) algorithm and Spearman’s correlation analysis, respectively. The SCC level and proinflammatory cytokines positively correlated with Sharpea and negatively correlated with Ruminococcaceae UCG-014, Ruminococcus flavefaciens, and Treponema saccharophilum. Furthermore, the metabolites xanthurenic acid, and 1-(1H-benzo[d]imidazol-2-yl) ethan-1-ol positively correlated with microbial biomarkers of healthy cows, whereas, xanthine, pantothenic acid, and anacardic acid were negatively correlated with the microbial biomarkers of mastitis cows. In conclusion, Ruminococcus flavefaciens and Treponema saccharophilum are potential strains for improving the health of dairy cows. The current study provides a novel perspective to assist in targeting the ruminal microbiota with preventive/therapeutic strategies against inflammatory diseases in the future.

Dietary Supplementation With Creatine Pyruvate Alters Rumen Microbiota Protein Function in Heat-Stressed Beef Cattle

Creatine pyruvate (CrPyr) is a new multifunctional nutrient that can provide both pyruvate and creatine. It has been shown to relieve the heat stress of beef cattle by improving antioxidant activity and rumen microbial protein synthesis, but the mechanism of CrPyr influencing rumen fermentation remains unclear. This study aimed to combine 16S rDNA sequencing and metaproteomics technologies to investigate the microbial composition and function in rumen fluid samples taken from heat-stressed beef cattle treated with or without 60 g/day CrPyr. 16S rDNA sequencing revealed that there were no significant differences in the α-diversity indices between the two groups. By analyzing the level profiles of 700 distinct proteins, we found that the CrPyr administration increased the expression of enzymes involved in specific metabolic pathways including (i) fatty acid β-oxidation; (ii) interconversion from pyruvate to phosphoenolpyruvate, oxaloacetate, acetyl-CoA, and malate; (iii) glycolysis/gluconeogenesis and citrate cycle metabolism; and (iv) biosynthesis of amino acids. These results indicated that the increased generation of adenosine triphosphate during fatty acid β-oxidation or citrate cycle and the up-regulation synthesis of microbial protein in rumen of beef cattle treated with CrPyr may help decrease oxidative stress, regulate energy metabolism, and further improve the rumen fermentation characteristic under heat stress.

Effect of Lipopolysaccharides (LPS) and Lipoteichoic Acid (LTA) on the Inflammatory Response in Rumen Epithelial Cells (REC) and the Impact of LPS on Claw Explants

Simple Summary

Endotoxins, often referred to as lipopolysaccharides (LPS), are bacterial toxins and play an essential role in several diseases in ruminants. One of the most common disorders in dairy cows, sub-acute rumen acidosis (SARA), is associated with a substantial increase of ruminal and intestinal endotoxin load. Other potentially harmful substances, e.g., lipoteichoic acid (LTA), derived from the cell wall of Gram-positive bacteria, might play an essential role during SARA as well. Besides the potential local effect of LPS, translocation to the blood can induce a strong immune response in cattle. Furthermore, LPS might reach the claw tissue after translocation. In our study, we used a cell culture model with epithelial cells isolated from rumen tissue to assess the effects of LPS and LTA. Furthermore, we evaluated the effects of LPS on claw tissue with an explant model. LPS and LTA could induce an inflammatory response in rumen epithelial cells. However, the effect of LPS was more substantial and seen at an earlier time point compared to LTA. Furthermore, in claw explants, LPS negatively affected the separation force, an indicator for tissue integrity, which decreased with increasing LPS concentrations. Overall, our data suggest that especially endotoxins can impact local inflammatory response in the rumen. Furthermore, if endotoxins reach the claw tissue, it might affect claw health.

Abstract

Endotoxins play a crucial role in ruminant health due to their deleterious effects on animal health. The study aimed to evaluate whether LPS and LTA can induce an inflammatory response in rumen epithelial cells. For this purpose, epithelial cells isolated from rumen tissue (REC) were stimulated with LPS and LTA for 1, 2, 4, and 24 h. Thereafter, the expression of selected genes of the LPS and LTA pathway and inflammatory response were evaluated. Furthermore, it was assessed whether LPS affects inflammatory response and structural integrity of claw explants. Therefore, claw explants were incubated with LPS for 4 h to assess the expression of selected genes and for 24 h to evaluate tissue integrity via separation force. LPS strongly affected the expression of genes related to inflammation (NFkB, TNF-α, IL1B, IL6, CXCL8, MMP9) in REC. LTA induced a delayed and weaker inflammatory response than LPS. In claw explants, LPS affected tissue integrity, as there was a concentration-dependent decrease of separation force. Incubation time had a strong effect on inflammatory genes in claw explants. Our data suggest that endotoxins can induce a local inflammatory response in the rumen epithelium. Furthermore, translocation of LPS might negatively impact claw health.

Improvement of colonic healing and surgical recovery with perioperative supplementation of inulin and galacto-oligosaccharides

BACKGROUND AND AIMS

Anastomotic leak (AL) is a major complication in colorectal surgery. Recent evidence suggests that the gut microbiota may affect healing and may cause or prevent AL. Butyrate is a beneficial short-chain fatty acid (SCFA) that is produced as a result of bacterial fermentation of dietary oligosaccharides and has been described as beneficial in the maintenance of colonic health. To assess the impact of oligosaccharides on colonic anastomotic healing in mice, we propose to modulate the microbiota with oligosaccharides to increase butyrate production via enhancement of butyrate-producing bacteria and, consequently, improve anastomotic healing in mice.

METHODS

Animal experiments were conducted in mice that were subjected to diets supplemented with inulin, galacto-oligosaccharides (GOS) or cellulose, as a control, for two weeks before undergoing a surgical colonic anastomosis. Macroscopic and histological assessment of the anastomosis was performed. Extent of epithelial proliferation was assessed by Ki-67 immunohistochemistry. Gelatin zymography was used to evaluate the extent of matrix metalloproteinase (MMP) hydrolytic activity.

RESULTS

Inulin and GOS diets were associated with increased butyrate production and better anastomotic healing. Histological analysis revealed an enhanced mucosal continuity, and this was associated with an increased re-epithelialization of the wound as determined by increased epithelial proliferation. Collagen concentration in peri-anastomotic tissue was higher with inulin and GOS diets and MMP activity, a marker of collagen degradation, was lower with both oligosaccharides. Inulin and GOS diets were further associated with lower bacterial translocation.

CONCLUSIONS

Dietary supplementation with inulin and GOS may improve anastomotic healing and reinforce the gut barrier in mice.

Thiamine Alleviates High-Concentrate-Diet-Induced Oxidative Stress, Apoptosis, and Protects the Rumen Epithelial Barrier Function in Goats

High-concentrate diets are continually used in ruminants to meet the needs of milk yield, which can lead to the occurrence of subacute rumen acidosis in ruminants. This study investigated the protective effects of dietary thiamine supplementation on the damage of the ruminal epithelium barrier function in goats fed a high-concentrate diet. Twenty-four healthy Boer goats (live weight of 35.62 ± 2.4 kg; age, 1 year) were randomly assigned into three treatments, with eight goats in each treatment, consuming one of three diets: a low-concentrate diet (CON; concentrate/forage, 30:70), a high-concentrate diet (HC; concentrate/forage, 70:30), or a high-concentrate diet with 200 mg of thiamine/kg of dry matter intake (HCT; concentrate/forage, 70:30) for 12 weeks. The additional dose of thiamine was based on our previous study wherein thiamine ameliorates inflammation. Compared with HC treatment, the HCT treatment had markedly higher concentrations of glutathione, superoxide dismutase, and glutathione peroxidase and total antioxidant capacity (P < 0.05) in plasma and rumen epithelium. The results showed that the apoptosis index was lower (P < 0.05) in the HCT treatment than in that of the HC treatment. Compared with the HC treatment, permeability and the electrophysiology parameter short circuit current for ruminal epithelial tissue were significantly decreased (P < 0.05) in the HCT treatment. The immunohistochemical results showed that the expression distribution of tight junctions including claudin-1, claudin-4, occludin, and zonula occludin-1 (ZO-1) was greater (P < 0.05) in the HCT treatments than in the HC treatment. The mRNA expression in the rumen epithelium of ZO-1, occludin, claudin-1, B-cell lymphoma/leukemia 2, nuclear factor erythroid-2 related factor 2 (Nrf2), superoxide dismutase 2 (SOD2), glutathione peroxidase 1, and the phase II metabolizing enzymes quinone oxidoreductase and heme oxygenase in the HCT group was significantly increased in comparison with the HC diet treatment (P < 0.05), whereas the mRNA expression of caspase 3, caspase 8, caspase 9, bcl-2 associated X protein, lipopolysaccharide binding protein, toll-like receptor 4, nuclear factor kappa-B (NFκB), tumor necrosis factor alpha, interleukin-1β, interleukin, and tumor necrosis factor receptor-associated factor 6 decreased significantly in the HCT treatment (P < 0.05). Compared with the HC treatment, the HCT diet significantly increased the protein expression of ZO-1, occludin, claudin-1, NQO1, HO-1, SOD2, serine/threonine kinase, p-Akt, Nrf2, and p-Nrf2; conversely, the expression of NFκB-related proteins p65 and pp65 was significantly decreased (P < 0.05). In addition, thiamine relieved the damage on the ruminal epithelium caused by the HC diet. The results show that dietary thiamine supplementation improves the rumen epithelial barrier function by regulating Nrf2-NFκB signaling pathways during high-concentrate-diet feeding.

Sodium Butyrate More Effectively Mitigates the Negative Effects of High-Concentrate Diet in Dairy Cows than Sodium β-Hydroxybutyrate via Reducing Free Bacterial Cell Wall Components in Rumen Fluid and Plasma

The present study was aimed at investigating the effects of sodium butyrate and sodium β-hydroxybutyrate on lactation and health of dairy cows fed a high-concentrate (HC) diet. Eighty mid-lactation dairy cows with an average milk yield of 33.75 ± 5.22 kg/d were randomly allocated to four groups (n = 20 per group) and were fed either a low-concentrate (LC) diet, a HC diet, the HC diet with 1% sodium butyrate (HCSB), or the HC diet with 1% sodium β-hydroxybutyrate (HCHB). The feeding trial lasted for 7 weeks, with a 2-week adaptation period and a 5-week measurement period, and the trial started from 96 ± 13 d in milk. Sodium butyrate supplementation delayed the decline in milk production and improved milk synthesis efficiency and milk fat content. Additionally, it decreased the proinflammatory cytokines and acute phase proteins (APPs) in plasma, the leucocytes in blood, the somatic cell count (SCC) in milk, and the gene expression of pattern recognition receptors (PRRs) and proinflammatory cytokines in the mammary gland, due to decreasing the contents of bacterial cell wall components (lipopolysaccharide, LPS; peptidoglycan, PGN; and lipoteichoic acid, LTA) in the rumen and plasma, compared with the HC diet. Sodium β-hydroxybutyrate supplementation also improved milk yield, milk synthesis efficiency and milk fat content and partially reduced the adverse effects caused by the HC diet, but it had no effect on decreasing bacterial cell wall components in the rumen and plasma, compared with the HC diet. Collectively, both sodium butyrate and sodium β-hydroxybutyrate mitigated the negative effects of HC diet on lactation and health of dairy cows, with sodium butyrate being more effective than sodium β-hydroxybutyrate.

Sodium butyrate attenuated iE-DAP induced inflammatory response in the mammary glands of dairy goats fed high-concentrate diet

BACKGROUND

Long-term high-concentrate (HC) diet feeding increased bacterial endotoxins, which translocated into the mammary glands of dairy goats and induced inflammatory response. γ-d-Glutamyl-meso-diaminopimelic acid (iE-DAP), bacterial peptidoglycan component, triggered inflammatory response through activating nucleotide oligomerization domain protein 1 (NOD1) signaling pathway. While dietary supplemented with sodium butyrate (SB) relieved inflammatory response and improved animal health and production. To investigate the effects and the mechanisms of action of SB on the inflammatory response in the mammary glands of dairy goats fed HC diet, 12 Saanen dairy goats were randomly assigned into HC group and SB regulated (BHC) group.

RESULTS

The results showed that SB supplementation attenuated ruminal pH decrease caused by HC diet in dairy goats resulting in a decrease of proinflammatory cytokines and iE-DAP plasma concentration and the mRNA expression of NOD1 and other inflammation-related genes. The protein levels of NOD1, NF-κB p65 and NF-κB pp65 were decreased by the SB supplementation. The expression of histone deacetylase 3 (HDAC3) was also inhibited by the SB supplementation. Meanwhile, the chromatin compaction ratios and DNA methylation levels of NOD1 and receptor-interacting protein 2 (RIP2) of BHC group were upregulated.

CONCLUSION

Collectively, the SB supplementation mitigated the inflammatory response in the mammary glands of dairy goats during HC-induced subacute ruminal acidosis (SARA) by inhibiting the activation of the NOD1/NF-κB signaling pathway through the decrease of the iE-DAP concentration in the rumen fluid and plasma and HDAC3 expression. DNA methylation and chromatin remodeling also contributed to the anti-inflammatory effect of SB. © 2020 Society of Chemical Industry.

Determination of γ-D-glutamyl-meso-diaminopimelic acid in rumen fluid of dairy cows by pre-column chiral derivatization-HPLC

High concentrate (HC) diet feeding leads to the lysis of rumen microbes and the release of hazardous metabolites, which can trigger inflammatory responses, thereby impairing dairy cow health and production. γ-D-glutamyl-meso-diaminopimelic acid (iE-DAP), which constitutes the peptidoglycan (PGN) layer of bacteria, is the minimum PGN structure capable of activating inflammatory signaling pathways. This research paper aimed to determine the iE-DAP concentration and investigate the effects of an HC diet on the concentration of iE-DAP in the rumen fluid of dairy cows. However, there are limited studies on the determination of iE-DAP concentration. Hence, we established a high-performance liquid chromatography (HPLC) method combined with pre-column chiral derivatization to detect the concentration of iE-DAP in rumen fluid. Moreover, we conducted an animal experiment that included 12 lactating Holstein cows, which were randomly divided into a low-concentrate (LC) group and an HC group. The results showed that the linear range of iE-DAP was 5-500 µg/mL and that the intra- and inter-day RSDs were lower than 7%. Meanwhile, this method was successfully applied to the analysis of iE-DAP in rumen fluid, and the results revealed that long-term feeding with an HC diet elevated the concentration of iE-DAP in rumen fluid of dairy cows.

Sodium butyrate reduces bovine mammary epithelial cell inflammatory responses induced by exogenous lipopolysaccharide, by inactivating NF-κB signaling

Exogenous molecules derived from catabolic states (e.g., fatty acids, β-hydroxybutyrate) during periods of stress such as the periparturient period or pathogen challenges [e.g., lipopolysaccharide (LPS)] can trigger an inflammatory response in tissues such as the liver and the mammary gland. Butyrate is one of the major short-chain fatty acids produced in the rumen, and work with non-ruminants has demonstrated that it can alter inflammatory processes. The primary objective of this study was to explore the preventive effect of sodium butyrate (SB) on LPS-induced inflammation in bovine mammary epithelial cells along with underlying molecular mechanisms. Immortalized bovine mammary epithelial cells (MAC-T) were treated with SB (0.1, 0.25, 0.5, 1, 2, or 5 mM) or with the histone deacetylase inhibitor trichostatin A (TSA; 6.25, 12.5, 25, or 50 nM) for 18 h, followed by a challenge with 1 µg/mL LPS for an additional 6 h. Pretreatment with SB prevented increase in apoptosis of LPS-challenged MAC-T cells in a dose-dependent manner. The LPS treatment upregulated mRNA abundance of tumor necrosis factor α (TNFA), interleukin-6 (IL6), and interleukin-1B (IL1B), whereas inhibition of histone deacetylase with TSA dampened this effect. More importantly, SB had clear dose-dependent effects on the inflammatory response by preventing upregulation of TNFA, IL6, and IL1B. Furthermore, pretreatment with TSA or SB attenuated the downregulation of histone H3 acetylation protein abundance induced by LPS. The greater ratio of p-IκB α/IκB α and p-p65/p65 protein abundance and the increase in nuclear localization of NF-κB p65 protein in response to LPS were attenuated by pretreatment with SB. Overall, the data indicated that exogenous SB alleviates mammary cell pro-inflammatory responses partly through post-translational mechanisms that diminish NF-κB signaling. Thus, the cytoprotective effect of SB against an inflammatory challenge might represent a preventive tool to help the mammary gland against pathogens such as those causing mastitis.

Diet starch concentration and starch fermentability affect markers of inflammatory response and oxidant status in dairy cows during the early postpartum period

Our objective was to evaluate the effects of diet starch concentration and starch fermentability on inflammatory response markers and oxidant status during the early postpartum (PP) period and its carryover effects. Fifty-two multiparous Holstein cows were used in a completely randomized block design experiment with a 2 × 2 factorial arrangement of treatments. Treatments were starch concentration and starch fermentability of diets; diets were formulated to 22% (low starch, LS) or 28% (high starch, HS) starch with dry-ground corn (DGC) or high-moisture corn (HMC) as the primary starch source. Treatments were fed from 1 to 23 d PP and then switched to a common diet until 72 d PP to measure carryover (CO) effects. Treatment period (TP) diets were formulated to 22% forage neutral detergent fiber and 17% crude protein. The diet for the CO period was formulated to 20% forage neutral detergent fiber, 17% crude protein, and 29% starch. Coccygeal blood was collected once a week during the TP and every second week during the CO period. Liver and adipose tissue biopsies were performed within 2 d PP and at 20 ± 3 d PP. Blood plasma was analyzed for concentrations of albumin, haptoglobin, reactive oxygen and nitrogen species (RONS), and antioxidant potential (AOP), with lipopolysaccharide-binding protein (LBP) and TNFα evaluated during the TP only. Oxidative stress index (OSi) was calculated as RONS/AOP. Abundance of mRNA from genes involved in inflammation and glucose metabolism in liver and genes involved in lipogenesis in adipose tissue were determined. Data were analyzed separately for the TP and CO periods. During the TP, treatments interacted to affect concentrations of TNFα, haptoglobin, and LBP, with HMC increasing their concentrations for HS (9.38 vs. 7.45 pg/mL, 0.45 vs. 0.37 mg/mL, and 5.94 vs. 4.48 μg/mL, respectively) and decreasing their concentrations for LS (4.76 vs. 12.9 pg/mL, 0.27 vs. 0.41 mg/mL, and 4.30 vs. 5.87 μg/mL, respectively) compared with DGC. Effects of treatments diminished over time for LBP and haptoglobin with no differences by the end of the TP and no main CO effects of treatment for haptoglobin. The opposite treatment interaction was observed for albumin, with HMC tending to decrease its concentration for HS (3.24 vs. 3.34 g/dL) and increase its concentration for LS (3.35 vs. 3.29 g/dL) compared with DGC, with no carryover effect. Feeding DGC increased the OSi during the first week of the TP compared with HMC, with this effect diminishing over time; during the CO period HMC increased OSi for HS and decreased it for LS compared with DGC, with this effect diminishing toward the end of CO. Feeding HMC increased the abundance of genes associated with inflammation and gluconeogenesis in liver for HS and decreased it for LS compared with DGC. Feeding HS increased the mRNA abundance of genes associated with adipose tissue lipogenesis compared with LS. Results during the TP suggest that feeding LS-DGC and HS-HMC elicited a more pronounced inflammatory response and induced an upregulation of genes associated with inflammation and gluconeogenesis in liver, without effects on OSi, but effects on plasma markers of inflammation diminished during the CO period.

Energy conservation involving 2 respiratory circuits

Chemiosmosis and substrate-level phosphorylation are the 2 mechanisms employed to form the biological energy currency adenosine triphosphate (ATP). During chemiosmosis, a transmembrane electrochemical ion gradient is harnessed by a rotary ATP synthase to phosphorylate adenosine diphosphate to ATP. In microorganisms, this ion gradient is usually composed of [Formula: see text], but it can also be composed of Na⁺ Here, we show that the strictly anaerobic rumen bacterium Pseudobutyrivibrio ruminis possesses 2 ATP synthases and 2 distinct respiratory enzymes, the ferredoxin:[Formula: see text] oxidoreductase (Rnf complex) and the energy-converting hydrogenase (Ech complex). In silico analyses revealed that 1 ATP synthase is [Formula: see text]-dependent and the other Na⁺-dependent, which was validated by biochemical analyses. Rnf and Ech activity was also biochemically identified and investigated in membranes of P. ruminis Furthermore, the physiology of the rumen bacterium and the role of the energy-conserving systems was investigated in dependence of 2 different catabolic pathways (the Embden-Meyerhof-Parnas or the pentose-phosphate pathway) and in dependence of Na⁺ availability. Growth of P. ruminis was greatly stimulated by Na⁺, and a combination of physiological, biochemical, and transcriptional analyses revealed the role of the energy conserving systems in P. ruminis under different metabolic scenarios. These data demonstrate the use of a 2-component ion circuit for [Formula: see text] bioenergetics and a 2nd 2-component ion circuit for Na⁺ bioenergetics in a strictly anaerobic rumen bacterium. In silico analyses infer that these 2 circuits are prevalent in a number of other strictly anaerobic microorganisms.

Thiamine ameliorates inflammation of the ruminal epithelium of Saanen goats suffering from subacute ruminal acidosis

This study aimed to examine the role of thiamine in the local inflammation of ruminal epithelium caused by high-concentrate diets. Eighteen mid-lactating (148 ± 3 d in milk; milk yield = 0.71 ± 0.0300 kg/d) Saanen goats (body weight = 36.5 ± 1.99 kg; body condition score = 2.73 ± 0.16, where 0 = emaciated and 5 = obese) in parity 1 or 2 were selected. The goats were randomly divided into 3 groups (n = 6/group): (1) control diet (concentrate:forage 30:70), (2) high-concentrate diet (HC; concentrate:forage 70:30), and (3) high-concentrate diet with 200 mg of thiamine/kg of dry matter intake (THC; concentrate:forage 70:30). Goats remained on experimental diets for 8 wk. On the last day of 8 wk, ruminal and blood samples were collected to determine ruminal parameters, endotoxin lipopolysaccharide, and blood inflammatory cytokines. Goats were slaughtered to collect ruminal tissue to determine gene and protein expression of toll-like receptor 4 (TLR4) signaling pathways. Thiamine supplementation increased ruminal pH (6.03 vs. 5.42) compared with the HC group. Propionate (21.08 vs. 31.61 mM), butyrate (12.08 vs. 19.39 mM), lactate (0.52 vs. 0.71 mM), and free lipopolysaccharide (42.16 vs. 55.87 × 10³ endotoxin units/mL) concentrations in ruminal fluid were lower in THC goats compared with HC goats. Similar to plasma interleukin 1β (IL-1β) concentration (209.31 vs. 257.23 pg/mL), blood CD8⁺ percentage (27.57 vs. 34.07%) also decreased in response to thiamine. Compared with HC goats, THC goats had lower ruminal epithelium activity of the enzymes myeloperoxidase and matrix metalloproteinase (MMP) 2 and 9. In contrast to HC, THC had downregulated mRNA expression of nuclear factor-κB (NFKB), TLR4, IL1B, MMP2, and MMP9 in ruminal epithelium. Thiamine supplementation led to lower relative protein expression of IL-1β, NF-κB unit p65, and phosphorylated NF-κB unit p65 in ruminal epithelium. Taken together, these results suggest that thiamine supplementation mitigates HC-induced local inflammation and ruminal epithelial disruption.

Sodium Butyrate Modulates Mucosal Inflammation Injury Mediated by GPR41/43 in the Cecum of Goats Fed a High Concentration Diet

Emerging data indicate that excessive short chain fatty acids can mediate the downstream mitogen-activated protein kinase pathways by activating G-protein coupled receptor 41/43 (GPR41/43) to initiate the inflammatory response. The current study was conducted to investigate if a high concentrate (HC) supplemented with sodium butyrate can alleviate the inflammation and if an epigenetic mechanism is involved in regulating the expression of the key GPR41/43 genes in the cecum. Twelve lactating goats were randomly divided into two groups: the control group fed the HC diet and the treatment group fed the HC diet supplemented with sodium butyrate (HCB). Our results suggested that the supplementation of sodium butyrate significantly increased the pH value in the rumen and cecum, downregulated the expression of GPR41/43 and related inflammatory cytokines, upregulated the expression of tight junction proteins, and reduced the protein expression levels of GPR 41/43, ERK1/2, and p38. Moreover, the ratios of DNA methylation and chromatin compaction in the promoter region of the GPR41/43 genes were altered due to the addition of sodium butyrate. In brief, dietary addition of sodium butyrate can reduce the inflammatory injury to the cecal mucosa in lactating goats and can affect the expression of GPR41/43 via epigenetic modification.

Microbial community shifts elicit inflammation in the caecal mucosa via the GPR41/43 signalling pathway during subacute ruminal acidosis

Background

Dietary structure in ruminants is closely connected with the composition of gastrointestinal microbiota. Merging study has shown that dietary induced SARA causes the alteration of microbial community in the cecum leading to the local inflammation. However, the mechanisms of cecum inflammation elicited by the shift of microbial flora in ruminants are largely unknown, and whether the development of this inflammation is modified by epigenetic modifications.

Results

Ten multiparous lactating goats were randomly seperated into two groups and received either a low concentrate diet (LC, 40% concentrate, n = 5) or a high concentrate diet (HC, 60% concentrate) to induce subacute ruminal acidosis (SARA). Compared with LC, HC-induced SARA altered the predominant phyla and genera, thereby increasing the concentration of lipopolysaccharide (LPS) and short chain fatty acids (SCFAs). Meanwhile, HC-induced SARA enhanced the mRNA expression of cytokines and chemokines and the expression of mRNA and protein of GPR41, GPR43, p38 and ERK1/2, while HC-induced SARA had no effect on TLR4 and p65. Furthermore, HC-induced SARA decreased the percentage of chromatin compaction and DNA methylation at the area of the promoters of GPR41 and GPR43.

Conclusion

This study indicated that HC diet induced SARA resulted in the alteration in the composition of cecal microbiota. This alteration increased the concentration of LPS, but failing to activate TLR4 signaling pathway due to the tolerance effect of intestinal epithelial cell to certain level of LPS, as well as elevated the concentration of SCFAs, thereby activating GPR41 and GPR43 signaling pathway to produce cytokines and chemokins and cause the cecal inflammation. And epigenetic mechanisms contributed to the development of this inflammation in the lactating goats suffering from SARA.

Electronic supplementary material

The online version of this article (10.1186/s12917-019-2031-5) contains supplementary material, which is available to authorized users.

Effects of High-Grain Diet With Buffering Agent on the Hepatic Metabolism in Lactating Goats

To gain insight on the effects of a high-grain diet with buffering agent on liver metabolism and the changes of plasma biochemical parameters and amino acids in hepatic vein and portal vein, commercial kit and high performance liquid chromatography (HPLC) were applied to determine the concentration of amino acids of hepatic vein and portal vein blood samples, quantitative real-time PCR and comparative proteomic approach was employed to investigate proteins differentially expressed in liver in lactating dairy goats feeding high-grain diet with buffering agent or only high-grain diet. Results showed that feeding high-grain diet with buffering agent to lactating dairy goats could outstanding increase amino acid content of Gln (p < 0.01), and the amino acid contents of Arg and Tyr in BG were significantly higher (p < 0.05) than that in HG. After adding the buffering agent, the metabolism of amino acids in the liver were changed and most of the amino acids were increasingly synthesized and decreasingly consumed in the liver. In addition, 46 differentially expressed protein spots (≥1.5-fold changed) were detected in buffering group vs. control group using 2-DE technique and MALDI-TOF/TOF proteomics analyzer. Of these, 24 proteins showed increased expression and 22 proteins showed decreased expression in the buffer group vs. control group. Data on Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis reveals that the high-grain diet with buffering agent alter the expression of proteins related to amino acids metabolism and glycometabolism. In addition, the results conclude that feeding high-grain diet with buffering agent can strengthen anti-oxidant capacity, stress ability, slow down urea metabolism, and alter amino acid metabolism as well as glycometabolism in the liver through different detection methods including proteomic analysis, real-time PCR analysis and biochemical analysis.

Targeting gut microbiota as a possible therapy for mastitis

Mastitis, a disease that affects both dairy herds and humans, is recognized as the most common source of losses in the dairy industry. Antibiotics have been used for years as the primary treatment for mastitis. However, abuse of antibiotics has led to the emergence of resistant strains and the presence of drug residues and has increased the difficulty of curing this disease. In addition, antibiotics kill most of the microbes that are present in the digestive tract, leading to imbalances in the gut microbiome and destruction of the ecosystem that is normally present in the gut. Gut microbiota play an important role in the host's health and could be considered the "second brain" of the body. In recent years, the gut microbiota and their metabolites, including lipopolysaccharide (LPS) and short-chain fatty acids (SCFAs), have been shown to participate in the development of mastitis. LPS is the main component of the cell walls of gram-negative bacteria. Overproduction of rumen-derived LPS injures the rumen epithelium, resulting in the entry of LPS into the blood and damaged liver function; once in the blood, it circulates into the mammary gland, increasing blood-barrier permeability and leading to mammary gland inflammation. SCFAs, which are produced by gut microbiota as fermentation products, have a protective effect on mammary gland inflammatory responses and help maintain the function of the blood-milk barrier. Recently, increasing attention has been focused on the use of probiotics as a promising alternative for the treatment of mastitis. This review summarizes the effects of the gut microbiome and its metabolites on mastitis as well as the current of probiotics in mastitis. This work may provide a valuable theoretical foundation for the development of fresh ideas for the prevention and treatment of mastitis.

Resveratrol modulates the gut microbiota to prevent murine colitis development through induction of Tregs and suppression of Th17 cells

Inflammatory diseases of the gastrointestinal tract are often associated with microbial dysbiosis. Thus, dietary interactions with intestinal microbiota, to maintain homeostasis, play a crucial role in regulation of clinical disorders such as colitis. In the current study, we investigated if resveratrol, a polyphenol found in a variety of foods and beverages, would reverse microbial dysbiosis induced during colitis. Administration of resveratrol attenuated colonic inflammation and clinical symptoms in the murine model of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis. Resveratrol treatment in mice with colitis led to an increase in CD4⁺ FOXP3⁺ and CD4⁺ IL-10⁺ T cells, and a decrease in CD4⁺ IFN-γ⁺ and CD4⁺ IL-17⁺ T cells. 16S rRNA gene sequencing to investigate alterations in the gut microbiota revealed that TNBS caused significant dysbiosis, which was reversed following resveratrol treatment. Analysis of cecal flush revealed that TNBS administration led to an increase in species such as Bacteroides acidifaciens, but decrease in species such as Ruminococcus gnavus and Akkermansia mucinphilia, as well as a decrease in SCFA i-butyric acid. However, resveratrol treatment restored the gut bacteria back to homeostatic levels, and increased production of i-butyric acid. Fecal transfer experiments confirmed the protective role of resveratrol-induced microbiota against colitis inasmuch as such recipient mice were more resistant to TNBS-colitis and exhibited polarization toward CD4⁺ FOXP3⁺ T cells and decreases in CD4⁺ IFN-γ⁺ and CD4⁺ IL-17⁺ T cells. Collectively, these data demonstrate that resveratrol-mediated attenuation of colitis results from reversal of microbial dysbiosis induced during colitis and such microbiota protect the host from colonic inflammation by inducing Tregs while suppressing inflammatory Th1/Th17 cells.

Sodium Butyrate Inhibits the Inflammation of Lipopolysaccharide-Induced Acute Lung Injury in Mice by Regulating the Toll-Like Receptor 4/Nuclear Factor κB Signaling Pathway

Bacterial pneumonia is a common disease in dairy herds worldwide, which brings great economic losses to farmers. Sodium butyrate (SB), an inhibitor of histone deacetylase, plays an important role in limiting inflammation. The purpose of this study was to investigate the protective effects of SB on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice and explore the potential mechanism of SB protection. A total of 30 ICR mice were randomly divided into three groups ( n = 10): a phosphate-buffered saline (PBS) intratracheal instillation group, a LPS intratracheal instillation group, and a SB gavage group (SB was given 1 h before the LPS stimulation). After 12 h, samples of the blood and lung tissue were collected from the mice for experimental analysis. The results showed that the concentration of inflammatory cytokines [interleukin 1β (IL1β) and tumor necrosis factor α (TNF-α)], myeloperoxidase (MPO) activity in the lung tissue and blood, protein abundance of toll-like receptor 4 (TLR4), nuclear factor κB (NF-κB, p65), phosphorylated p65 (p-p65), inhibitor κBα (IκBα), and phosphorylated IκBα (p-IκBα), and relative mRNA expression of genes associated with inflammation, such as TLR4, NF-κB, IL1β, interleukin 6 (IL6), and TNF-α, were significantly upregulated in the LPS group compared to the PBS group. However, the SB addition markedly downregulated the levels of these parameters in the LSB group compared to those in the LPS group. Furthermore, the structure of the lung tissue from the LPS group was severely disrupted in comparison to that of the PBS group. However, with SB administration, the severe structural disruption was relieved. In addition, an immunohistochemical analysis showed that positive immunoreactions to TLR4, p65, and TNF-α were significant in the LPS group; however, SB addition markedly attenuated this phenomenon. In conclusion, the ALI mouse model was successfully established with an intratracheal instillation of LPS. Furthermore, gavage with SB inhibited inflammation in LPS-induced ALI.

Dietary Addition of Sodium Butyrate Contributes to Attenuated Feeding-Induced Hepatocyte Apoptosis in Dairy Goats

The present study aims to reveal the mechanisms of hepatocyte apoptosis induced by dietary feeding. Eighteen midlactating goats were randomly divided into three groups: the low concentrate group (LC), the high concentrate group (HC), and the sodium butyrate (SB)-supplemented group (SHC). After 10 weeks, the HC diet successfully induced subacute ruminal acidosis (SARA), which increased the lipopolysaccharide (LPS) and cytokine concentrations and the expression of genes and proteins related to inflammation and apoptosis. The addition of SB to the HC diet notably decreased the levels of those parameters. Additionally, Bcl2 mRNA and protein expression was lower in the HC group than those in the LC and SHC groups. Furthermore, the HC diet reduced the percentages of caspase 3 and 8 promoter methylation compared to those of goats fed the LC diet, whereas the SHC diet partially recovered the methylation ratio to reduce caspase 3 and 8 expression. Collectively, HC diet-induced SARA caused hepatocyte apoptosis via activating the extrinsic apoptosis pathway, whereas dietary addition of SB depressed the inflammatory response and attenuated hepatocyte apoptosis. DNA methylation contributed to regulation of the expression of key apoptotic genes in the livers of lactating goats.

Buffering agent via insulin-mediated activation of PI3K/AKT signaling pathway to regulate lipid metabolism in lactating goats

Ruminants are often fed a high-concentrate (HC) diet to meet lactating demands, yet long-term concentrate feeding induces subacute ruminal acidosis (SARA) and leads to a decrease in milk fat. Buffering agent could enhance the acid base buffer capacity and has been used to prevent ruminant rumen SARA and improve the content of milk fat. Therefore, we tested whether a buffering agent increases lipid anabolism in the livers of goats and influences of milk fat synthesis. Twelve Saanen-lactating goats were randomly assigned to two groups: one group received a HC diet (Concentrate: Forage=60:40, Control) and the other group received the same diet with a buffering agent added (10 g sodium butyrate, C(4)H(7)NaO(2); 10 g sodium bicarbonate, NaHCO(3); BG) over a 20-week experimental period. Overall, milk fat increase (4.25+/-0.08 vs. 3.24+/-0.10; P<0.05), and lipopolysaccharide levels in the jugular (1.82+/-0.14 vs. 3.76+/-0.33) and rumen fluid (23,340+/-134 vs. 42,550+/-136) decreased in the buffering agent group (P<0.05). Liver consumption and release of nonesterified fatty acid (NEFA) into the bloodstream increased (P<0.05). Phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT) and ribosomal protein S6 kinase (p70S6K) up-regulated significantly in the livers of the buffering agent group (P<0.05). It also up-regulated expression of the transcription factor sterol regulatory element binding protein-1c (SREBP-1c) and its downstream targets involved in fatty acid synthetic, including fatty acid synthetase (FAS), stearoyl-CoA desaturase (SCD-1) and acetyl-CoA carboxylase 1 (ACC1) (P<0.05). The BG diet increased insulin levels in blood (19.43+/-0.18 vs. 13.81+/-0.10, P<0.05), and insulin receptor was likewise elevated in the liver (P<0.05). Cumulatively, the BG diet increased plasma concentrations of NEFA by INS-PI3K/AKTSREBP-1c signaling pathway promoting their synthesis in the liver. The increased NEFA concentration in the blood during BG feeding may explain the up-regulated in the milk fat of lactating goats.

Sodium Butyrate Supplementation Alleviates the Adaptive Response to Inflammation and Modulates Fatty Acid Metabolism in Lipopolysaccharide-Stimulated Bovine Hepatocytes

This study aimed to evaluate whether sodium butyrate (SB) attenuates the hepatic response to LPS-induced inflammation in bovine hepatocytes. Hepatocytes isolated from cows at ∼160 days in milk (DIM) were exposed to 0.5 mmol/L SB for 18 h as pretreatment. Cells pretreated with SB were used for the SB group, and those subjected to 4 μg/mL lipopolysaccharide (LPS) challenge for 6 h were used for the lipopolysaccharide pretreated with SB (LSB) group. The LPS-challenged hepatocytes showed increases in TNF-α and IL-6 production in culture medium (37 ± 11, P < 0.05); these increases were attenuated by pretreatment with SB in the LSB group (267 ± 4, P < 0.05). Compared to that in LPS-treated cells, the phospho-p65 and phospho-IκBα protein expression and nuclear translocation were suppressed when SB was added. Genes ( SREBP1c, SCD1, and DGAT1) and proteins (SREBP1c and SCD1) related to fatty acid metabolism were upregulated in LSB cells compared to those in LPS-treated cells ( P < 0.05). The ratios of phospho-AMPKα to AMPKα (0.32 ± 0.03 vs 0.70 ± 0.07) and phospho-ACCα to ACCα were decreased (0.81 ± 0.06 vs 2.06 ± 0.16) ( P < 0.05) in the LSB group. SB pretreatment reversed the histone H3 deacetylation that was increased by LPS stimulation in bovine hepatocytes (0.54 ± 0.02 vs 1.27 ± 0.11, P < 0.05). Our results suggest that SB pretreatment suppresses the hepatocyte changes that occur during the LPS-induced inflammatory response, which is accompanied by enhanced fatty acid synthesis, downregulated fatty acid oxidation, and histone H3 deacetylation, thus neutralizing the negative effects of infection.

Dietary Sodium Butyrate Supplementation Reduces High-Concentrate Diet Feeding-Induced Apoptosis in Mammary Cells in Dairy Goats

Eighteen lactating goats (38.86 ± 2.06 kg) were randomly allocated to three groups. One group was fed a low-concentrate (LC) diet (forage:concentrate = 6:4), while the other two groups were fed a high-concentrate (HC) diet (forage:concentrate = 4:6) or an HC diet supplemented with sodium butyrate (BHC) for 20 weeks. Samples of ruminal fluid, milk, hepatic blood plasma, and mammary gland tissue were prepared for the experimental analysis. The lipopolysaccharide (LPS) concentration, caspase-3 and -8 enzymatic activity, caspase-3 and -8 mRNA expression, and NF-κB (p65), phosphorylated-p65, bax, cytochrome c, and caspase-3 protein expression were higher in the HC group than those in the LC group; however, the levels of these parameters were lower in the BHC group than those in the HC group. Moreover, bcl-2 mRNA and protein expression was higher in the BHC group than that in the HC or LC groups, and no significant difference was observed between the HC and LC groups. Thus, feeding lactating goats an HC diet induces apoptosis in mammary cells, and supplementing the diet with sodium butyrate reduces the concentrations of LPS and proinflammatory cytokines, subsequently attenuating the activation of NF-κB and caspase-3 and eventually inhibiting apoptosis in mammary cells.