circATAD2 mitigates CD8+ T cells antitumor immune surveillance in breast cancer via IGF2BP3/m6A/PD-L1 manner.

Immune surveillance and chemotherapy sensitivity play critical functions in the tumorigenesis of breast cancer (BC). Emerging findings have indicated that circular RNA (circRNA) and N6-methyladenosine (m6A) both participate in the BC tumorigenesis. Here, present study aimed to investigate the roles of m6A-modified circATAD2 on BC and explore better understanding for BC precision therapeutic. Results reported that m6A-modifid circRNA (m6A-circRNA) microarray revealed the m6A-circRNA landscape in BC. M6A-modifid circATAD2 upregulated in BC samples and was closely correlated to poor prognosis. Functionally, circATAD2 promoted the immune evasion of BC cells and reduced the CD8+ T cells' killing effect. Mechanistically, MeRIP-seq unveiled the m6A modification in the 3'-UTR of PD-L1 mRNA, which was bound by circATAD2 and recognized by m6A reader IGF2BP3 to enhance PD-L1 mRNA stability and expression. In summary, these findings revealed the circATAD2/m6A/IGF2BP3/PD-L1 axis in BC immune surveillance, suggesting the potential that circATAD2 as a potential target for PD-L1-mediated BC.

Effects of nanoselenium supplementation on lactation performance, nutrient digestion and mammary gland development in dairy cows.

The objective of this experiment was to evaluate the influence of nanoselenium (NANO-Se) addition on milk production, milk fatty acid synthesis, the development and metabolism regulation of mammary gland in dairy cows. Forty-eight Holstein dairy cows averaging 720 ± 16.8 kg of body weight, 66.9 ± 3.84 d in milk (dry matter intake [DIM]) and 35.2 ± 1.66 kg/d of milk production were divided into four treatments blocked by DIM and milk yields. Treatments were control group, low-Se (LSe), medium-Se (MSe) and high-Se (HSe) with 0, 0.1, 0.2 and 0.3 mg Se, respectively, from NANO-Se per kg dietary dry matter (DM). Production of energy- and fat-corrected milk (FCM) and milk fat quadratically increased (p < 0.05), while milk lactose yields linearly increased (p < 0.05) with increasing NANO-Se addition. The proportion of saturated fatty acids (SFAs) linearly decreased (p < 0.05), while proportions of monounsaturated fatty acids (MUFAs) linearly increased and polyunsaturated fatty acids (PUFAs) quadratically increased. The digestibility of dietary DM, organic matter (OM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) quadratically increased (p < 0.05). Ruminal pH quadratically decreased (p < 0.01), while total VFA linearly increased (p < 0.05) with increasing NANO-Se addition. The acetic to propionic ratio decreased (p < 0.05) linearly due to the unaltered acetic molar percentage and a quadratical increase in propionic molar percentage. The activity of CMCase, xylanase, cellobiase and pectinase increased linearly (p < 0.05) following NANO-Se addition. The activity of α-amylase increased linearly (p < 0.01) with an increase in NANO-Se dosage. Blood glucose, total protein, estradiol, prolactin, IGF-1 and Se linearly increased (p < 0.05), while urea nitrogen concentration quadratically decreased (p = 0.04). Moreover, the addition of Se at 0.3 mg/kg from NANO-Se promoted (p < 0.05) mRNA and protein expression of PPARγ, SREBP1, ACACA, FASN, SCD, CCNA2, CCND1, PCNA, Bcl-2 and the ratios of p-ACACA/ACACA and BCL2/BAX4, but decreased (p < 0.05) mRNA and protein expressions of Bax, Caspase-3 and Caspase-9. The results suggest that milk production and milk fat synthesis increased by NANO-Se addition by stimulating rumen fermentation, nutrients digestion, gene and protein expressions concerned with milk fat synthesis and mammary gland development.

Stabilizing Zn Metal Anode Through Regulation of Zn Ion Transfer and Interfacial Behavior with a Fast Ion Conductor Protective Layer.

Aqueous Zn-ion batteries (AZIBs) attract intensive attention owing to their environmental friendliness, cost-effectiveness, innate safety, and high specific capacity. However, the practical applications of AZIBs are hindered by several adverse phenomena, including corrosion, Zn dendrites, and hydrogen evolution. Herein, a Zn anode decorated with a 3D porous-structured Na3 V2 (PO4)3 (NVP@Zn) is obtained, where the NVP reconstruct the electrolyte/anode interface. The resulting NVP@Zn anode can provide a large quantity of fast and stable channels, facilitating enhanced Zn ion deposition kinetics and regulating the Zn ions transport process through the ion confinement effect. The NASICON-type NVP protective layer promote the desolvation process due to its nanopore structure, thus effectively avoiding side reactions. Theoretical calculations indicate that the NVP@Zn electrode has a higher Zn ion binding energy and a higher migration barrier, which demonstrates that NVP protective layer can enhance Zn ion deposition kinetics and prevent the unfettered 2D diffusion of Zn ions. Therefore, the results show that NVP@Zn/MnO2 full cell can maintain a high specific discharge capacity of 168 mAh g-1 and a high-capacity retention rate of 74.6% after cycling. The extraordinary results obtained with this strategy have confirmed the promising applications of NVP in high-performance AZIBs.

Effects of folic acid and riboflavin on growth performance, nutrient digestion and rumen fermentation in Angus bulls.

This study examined the influences of coated folic acid (CFA) and coated riboflavin (CRF) on bull performance, nutrients digestion and ruminal fermentation. Forty-eight Angus bulls based on a randomised block and 2 × 2 factorial design were assigned to four treatments. The CFA of 0 or 6 mg of folic acid/kg DM was supplemented in diets with CRF 0 or 60 mg riboflavin (RF)/kg DM. Supplementation of CRF in diets with CFA had greater increase in daily weight gain and feed efficiency than in diets without CFA. Supplementation with CFA or CRF enhanced digestibility of DM, organic matter, crude protein, neutral-detergent fibre and non-fibre carbohydrate. Ruminal pH and ammonia N content decreased and total volatile fatty acids concentration and acetate to propionate ratio elevated for CFA or CRF addition. Supplement of CFA or CRF increased the activities of fibrolytic enzymes and the numbers of total bacteria, protozoa, fungi, dominant fibrolytic bacteria and Prevotella ruminicola. The activities of α-amylase, protease and pectinase and the numbers of Butyrivibrio fibrisolvens and Ruminobacter amylophilus were increased by CFA but were unaffected by CRF. Blood concentration of folate elevated and homocysteine decreased for CFA addition. The CRF supplementation elevated blood concentrations of folate and RF. These findings suggested that CFA or CRF inclusion had facilitating effects on performance and ruminal fermentation, and combined addition of CFA and CRF had greater increase in performance than CFA or CRF addition alone in bulls.

Effects of dietary folic acid supplementation on lactation performance and mammary epithelial cell development of dairy cows and its regulatory mechanism.

The experiment investigated the impacts of FA on the proliferation of bovine mammary gland epithelial cells (BMECs) and to investigate the underlying mechanisms. Supplementation of 10 µM FA elevated the mRNA expression of proliferating cell nuclear antigen (PCNA), cyclin A2 and cyclin D1, and protein expression of PCNA and Cyclin A1. The mRNA and protein expression of B-cell lymphoma-2 (BCL2) and the BCL2 to BCL2 associated X 4 (BAX4) ratio elevated, while that of BAX, Caspase-3 and Caspase-9 reduced by FA. Both Akt and mTOR signaling pathways were activated by FA. Moreover, the stimulation of BMECs proliferation, the alteration of proliferative genes and protein expression, the change of apoptotic genes and protein expression, and the activation of mTOR signaling pathway caused by FA were obstructed by Akt inhibitor. Suppression of mTOR with Rapamycin reversed the FA-modulated promotion of BMECs proliferation and change of proliferous genes and protein expression, with no impact on mRNA or proteins expression related to apoptosis and FA-activated Akt signaling pathway. Supplementation of rumen-protected FA in cow diets evaluated milk yields and serum insulin-like growth factor-1 and estradiol levels. The results implied that the proliferation of BMECs was stimulated by FA through the Akt-mTOR signaling pathway.

Effects of guanidinoacetic acid supplementation on lactation performance, nutrient digestion and rumen fermentation in Holstein dairy cows.

BACKGROUND: Considering the high energy demand of lactation and the potential of guanidinoacetic acid (GAA) addition on the increase in creatine supply for cows, the present study investigated the effects of 0, 0.3, 0.6 and 0.9 g kg-1 dry matter (DM) of GAA supplementation on lactation performance, nutrient digestion and ruminal fermentation in dairy cows. The study used 40 mid-lactation multiparous Holstein cows and the study duration was 100 days. RESULTS: DM intake was not affected, but milk and milk component yields and feed efficiency increased linearly with increasing GAA addition. The total-tract digestibility of DM, organic matter, neutral detergent fibre, acid detergent fibre and non-fibre carbohydrates increased linearly and that of crude protein increased quadratically with increasing GAA addition. When the addition level of GAA increased, ruminal pH, molar percentages of butyrate, isobutyrate and isovalerate and the acetate-to-propionate ratio decreased linearly, and the total volatile fatty acids concentration and propionate molar percentage also increased linearly, whereas the acetate molar percentage and ammonia-N concentration were unaltered. The activities of fibrolytic enzymes, α-amylase and protease increased linearly. The populations of total bacteria, fungi, Ruminococcus albus, Fibrobacter succinogenes, Ruminococcus flavefaciens, Ruminobacter amylophilus and Prevotella ruminicola increased linearly, whereas protozoa and methanogens decreased linearly with increasing GAA addition. As for the blood metabolites, concentrations of glucose, urea nitrogen and methionine were unchanged, total protein, albumin, creatine and homocysteine increased linearly, and folate decreased linearly with increasing GAA supply. CONCLUSION: The results of the present study indicate that supplementation of GAA improved milk performance and rumen fermentation in lactating dairy cows. © 2022 Society of Chemical Industry.

Effects of folic acid and cobalt sulphate supplementation on growth performance, nutrient digestion, rumen fermentation and blood metabolites in Holstein calves.

To investigate the influences of cobalt (Co) and folic acid (FA) on growth performance and rumen fermentation, Holstein male calves (n 40) were randomly assigned to four groups according to their body weights. Cobalt sulphate at 0 or 0·11 mg Co/kg DM and FA at 0 or 7·2 mg/kg DM were used in a 2 × 2 factorial design. Average daily gain was elevated with FA or Co supplementation, but the elevation was greater for supplementing Co in diets without FA than with FA. Supplementing FA or Co increased DM intake and total-tract nutrient digestibility. Rumen pH was unaltered with FA but reduced with Co supplementation. Concentration of rumen total volatile fatty acids was elevated with FA or Co inclusion. Acetate percentage and acetate to propionate ratio were elevated with FA inclusion. Supplementing Co decreased acetate percentage and increased propionate percentage. Activities of xylanase and α-amylase and populations of total bacteria, fungi, protozoa, Ruminococcus albus, Fibrobacter succinogenes and Prevotella ruminicola increased with FA or Co inclusion. Activities of carboxymethyl-cellulase and pectinase increased with FA inclusion and population of methanogens decreased with Co addition. Blood folates increased and homocysteine decreased with FA inclusion. Blood glucose and vitamin B12 increased with Co addition. The data suggested that supplementing 0·11 mg Co/kg DM in diets containing 0·09 mg Co/kg DM increased growth performance and nutrient digestibility but had no improvement on the effects of FA addition in calves.

Evaluation of gallnut tannin and Lactobacillus plantarum as natural modifiers for alfalfa silage: Ensiling characteristics, in vitro ruminal methane production, fermentation profile and microbiota.

AIMS: The potential of gallnut tannin (GT) and Lactobacillus plantarum (LP) on fermentation characteristics, in vitro ruminal methane (CH4 ) production and microbiota of alfalfa silage was investigated. METHODS AND RESULTS: Alfalfa was ensiled with GT (20 and 50 g kg-1 dry matter [DM]) and LP (3 × 108  CFU per gram fresh matter) alone or in combination for 60 days. The GT and LP alone or in combination decreased DM losses, pH and non-protein nitrogen contents of alfalfa silage. All additive treatments decreased ruminal CH4 production, and increased propionic acid molar proportions and Fibrobacter succinogenes numbers. The LP treatment increased nutrient degradation, cellobiase, pectinase and protease activities, and Prevotella ruminicola abundance, whereas high-dose GT treatment inhibited these variables. Importantly, LP together with GT alleviated the adverse effects of high-dose GT supply alone by enhancing pectinase and protease activities as well as Rumincoccus flavefaciens and P. ruminicola growth. CONCLUSIONS: Combination of GT and LP can be used as an efficient additive to improve silage quality and utilization by ruminants. SIGNIFICANCE AND IMPACT OF THE STUDY: Using GT-LP combination has practical implications, particularly concerning effects of tannins on ruminal CH4 mitigation, which may alleviate inhibitory effects of tannins on feed digestion through modulating ruminal microbiota.

Comparison of the microbial communities of alpacas and sheep fed diets with three different ratios of corn stalk to concentrate.

The objective of this study was to investigate the characteristics of ruminal microbial communities of alpacas (Lama pacos) and sheep (Ovis aries) fed three diets with varying ratios of roughage (corn stalk) to concentrate, 3:7 (LS), 5:5 (MS) and 7:3 (HS). Six alpacas (one-year-old and weighing 29.5 ± 7.1 kg) and six sheep (one-year-old and weighing 27.9 ± 2.7 kg) were used in this study, in a replicated 3 × 3 Latin square experiment. Total protozoa concentration was determined under the microscope; total fungi and methanogens were assessed using quantitative polymerase chain reaction and expressed as a percentage of total bacterial 16S rRNA gene copies; bacterial communities were investigated by targeted 16S rRNA gene (V3-V4 region) sequencing. The percentage of fungi was significantly higher in alpacas than in sheep under the LS diet, while the concentration of protozoa was significantly lower in alpacas under HS, MS and LS diets. The alpha diversity including Shannon, Chao l and ACE indices of bacterial communities was higher in alpacas than in sheep, under the LS diet. A total of 299 genera belonging to 22 phyla were observed in the forestomach of alpaca and sheep, with Bacteroidetes and Firmicutes dominating both animal species. Phyla Armatimonadetes and Fusobacteria, as well as 64 genera, were detected only in alpacas, whereas phyla Acidobacteria and Nitrospira, as well as 44 genera, were found only in sheep. The abundance of cellulolytic bacteria, including Butyrivibrio and Pseudobutyrivibrio, was higher in alpacas than in sheep under all three diets. These differences in the forestomach microbial communities partly explained why alpacas displayed a higher poor-quality roughage digestibility, and a lower methane production. Results also revealed that the adverse effects of high-concentrate diets (70%) were lesser in alpacas than in sheep.

Effects of branched-chain volatile fatty acids and fibrolytic enzyme on rumen development in pre- and post-weaned Holstein dairy calves.

The study evaluated the effects of branched-chain volatile fatty acids (BCVFA) and fibrolytic enzyme (FE) on rumen development in calves. Forty Holstein male calves at the same ages (15 ± 2.5 days of age) and weights (45 ± 3.3 kg of body weight [BW]) were assigned randomly to four groups with a 2 × 2 factorial arrangement of treatments. Supplemental BCVFA (0 g/d or 18 g/d) and FE (0 g/d or 1.83 g/d) were fed to calves. Data were analyzed as a 2 × 2 factorial arrangement random design by the mixed procedure of SAS. The BCVFA × FE interaction was observed for ruminal propionate, blood growth hormone (GH) and insulin-like growth factor-1 (IGF-1), and GH receptor (GHR) and IGF-1 receptor (IGF-1R) expression in the rumen mucosa. Dry matter intake was higher for BCVFA addition. The higher average daily gain and ruminal volatile fatty acids were observed for BCVFA or FE addition. Stomach weight and the length and width of rumen papillae were higher for BCVFA addition. The higher expression of GHR, IGF-1R and 3-hydroxy-3-methylglutaryl-CoA synthase 1 in rumen mucosa, and blood GH and IGF-1 were observed with BCVFA or FE addition. Blood ß-hydroxybutyrate and acetoacetate were higher for BCVFA addition. The results indicated that rumen development was promoted by BCVFA, but was not affected with FE addition in calves.

Effects of soybean oil and dietary copper levels on nutrient digestion, ruminal fermentation, enzyme activity, microflora and microbial protein synthesis in dairy bulls.

The study evaluated the effects of soybean oil (SO) and dietary copper levels on nutrient digestion, ruminal fermentation, enzyme activity, microflora and microbial protein synthesis in dairy bulls. Eight Holstein rumen-cannulated bulls (14 ± 0.2 months of age and 326 ± 8.9 kg of body weight) were allocated into a replicated 4 × 4 Latin square design in a 2 × 2 factorial arrangement with factors being 0 or 40 g/kg dietary dry matter (DM) of SO and 0 or 7.68 mg/kg DM of Cu from copper sulphate (CS). The basal diet contained per kg DM 500 g of corn silage, 500 g of concentrate, 28 g of ether extract (EE) and 7.5 mg of Cu. The SO × CS interaction was significant (p < 0.05) for ruminal propionate proportion and acetate to propionate ratio. Dietary SO addition increased (p < 0.05) intake and total tract digestibility of EE but did not affect average daily gain (ADG) of bulls. Dietary CS addition did not affect nutrient intake but increased (p < 0.05) ADG and total tract digestibility of DM, organic matter, crude protein and neutral detergent fibre. Ruminal pH was not affected by treatments. Dietary SO addition did not affect ruminal total volatile fatty acids (VFA) concentration, decreased (p < 0.05) acetate proportion and ammonia N and increased (p < 0.05) propionate proportion. Dietary CS addition did not affect ammonia N, increased (p < 0.05) total VFA concentration and acetate proportion and decreased (p < 0.05) propionate proportion. Acetate to propionate ratio decreased (p < 0.05) with SO addition and increased (p < 0.05) with CS addition. Dietary SO addition decreased (p < 0.05) activity of carboxymethyl cellulase, cellobiase and xylanase as well as population of fungi, protozoa, methanogens, Ruminococcus albus and R. flavefaciens but increased (p < 0.05) α-amylase activity and population of Prevotella ruminicola and Ruminobacter amylophilus. Dietary CS addition increased (p < 0.05) activity of cellulolytic enzyme and protease as well as population of total bacteria, fungi, protozoa, methanogens, primary cellulolytic and proteolytic bacteria. Microbial protein synthesis was unchanged with SO addition but increased (p < 0.05) with CS addition. The results indicated that the addition of CS promoted nutrient digestion and ruminal fermentation by stimulating microbial growth and enzyme activity but did not relieve the negative effects of SO addition on ruminal fermentation in dairy bulls.

Effects of folic acid on growth performance, ruminal fermentation, nutrient digestibility and urinary excretion of purine derivatives in post-weaned dairy calves.

This study evaluated the effects of folic acid (FA) supplementation on growth performance, ruminal fermentation, nutrient digestibility and urinary purine derivatives (PD) excretion in dairy calves. Forty-eight Chinese Holstein male dairy calves at 60 ± 3.2 d of age and 89 ± 5.9 kg body weight (mean ± standard error) were assigned to one of four groups in a randomised block design. Calves in control group were fed basal diet, calves in low FA, medium FA and high FA groups with 3.6, 7.2 and 10.8 mg FA per kg basal diet, respectively. The dietary corn silage to concentrate ratio was 50:50 (dry matter [DM] basis). DM intake and average daily gain (ADG) quadratically increased, and feed conversion ratio quadratically decreased with increasing FA supplementation. Ruminal pH linearly decreased, whereas total volatile fatty acids quadratically increased. The unchanged acetate-to-propionate ratio was due to the similar change in acetate and propionate concentration. Ammonia N content quadratically decreased. Digestibility of DM, organic matter, crude protein, ether extract, neutral detergent fibre and acid detergent fibre linearly increased. Activities of carboxymethyl cellulase, cellobiase, xylanase and pectinase linearly increased, but α-amylase and protease quadratically increased. Abundance of Ruminococcus albus, Ruminococcus flavefaciens and Fibrobacter succinogenes linearly increased, but Butyrivibrio fibrisolvens and Prevotella ruminicola quadratically increased. Urinary total PD excretion quadratically increased. The results indicated that FA supplementation increased ADG, ruminal fermentation and nutrient digestibility with promoted ruminal microbial growth and enzyme activity, and the optimum dose was 7.2 mg FA per kg basal diet for calves.

Effects of rumen-protected folic acid and dietary protein level on growth performance, ruminal fermentation, nutrient digestibility and hepatic gene expression of dairy calves.

This study evaluated the effects of rumen-protected folic acid (RPFA) supplementation and dietary protein level on growth performance, ruminal fermentation, nutrient digestibility and hepatic gene expression in calves. Forty Holstein male calves (161 ± 5.7 days of age and 192 ± 5.4 kg of body weight) were assigned to one of four groups in a randomized experimental design with a 2 × 2 factorial arrangement. Moderate crude protein (130.1 g CP/kg [MCP] or high crude protein (150.2 g CP/kg [HCP]) diets were fed without (RPFA-) or with 3.6 mg FA (RPFA+) as RPFA per kg dietary dry matter (DM). Calves were fed a total mixed ration with a corn silage to concentrate ratio of 50:50 on a DM basis. The CP×RPFA interaction was not significant for any of the studied variables. The unchanged DM intake, higher average daily gain and lower feed conversion ratio were observed for HCP or RPFA+. Ruminal pH was lower, and total volatile fatty acids (VFA) concentration was higher for HCP or RPFA+. Acetate proportion was higher, and propionate proportion was lower for HCP or RPFA+. As a result, the higher acetate to propionate ratio was observed. Ruminal ammonia N was higher for HCP, but was lower with RPFA supplementation. The higher digestibility of DM, OM, CP and NDF was observed. Blood glucose and insulin were unchanged, but albumin, total protein, GH and IGF-1 were higher. Similarly, the higher hepatic expression of GH, IGF-1, GHR, IGF-1R, PI3K, mTOR and P70S6K was observed for HCP or RPFA+. The results indicated that increasing dietary CP content or supplementation with RPFA promoted growth performance of calves by improving nutrient utilization and up-regulating hepatic expression of gene related to protein synthesis.

Effects of sodium selenite addition on ruminal fermentation, microflora and urinary excretion of purine derivatives in Holstein dairy bulls.

Researches on sodium selenite (SS) mainly focus on production performance and rumen fermentation in ruminants, and the influence of dietary Se addition on ruminal microbial population and enzyme activity in dairy bulls is scarce. This study mainly evaluated the effects of SS on ruminal fermentation, microflora and urinary excretion of purine derivatives (PD) in dairy bulls. Eight ruminally cannulated dairy bulls were used in a replicated 4 × 4 Latin square design. Treatments were control, low SS (LSS), medium SS (MSS) and high SS (HSS) with 0, 0.1, 0.3 and 0.5 mg/kg of selenium (Se) from SS in dietary dry matter (DM), respectively. The supplement of SS (1.0 g/kg of Se) was mixed into the first third of the daily ration. Bulls were fed a total mixed ration with corn silage to concentrate ratio of 50:50 on a DM basis. Dry matter intake was not affected, average daily gain linearly increased, while feed conversion ratio quadratically decreased with increasing Se addition. The linearly increased digestibility of DM, organic matter, crude protein, ether extract, neutral detergent fibre and acid detergent fibre was observed. Both ruminal pH and ammonia-N concentration linearly decreased, whereas total volatile fatty acid concentration linearly increased. A lower acetate to propionate ratio was observed due to the unchanged acetate proportion and increased propionate proportion. Activity of cellobiase, xylanase, pectinase, α-amylase and protease, populations of total bacteria, fungi, protozoa, Ruminococcus (R.) albus, R. flavefaciens, Fibrobacter succinogenes, Butyrivibrio fibrisolvens and Ruminobacter amylophilus as well as urinary total PD excretion linearly increased, whereas populations of total methanogens and Prevotella ruminicola linearly decreased. The data indicated that dietary Se addition stimulated ruminal microbial growth and enzyme activity, and resulting in the increased nutrient digestion and growth performance, and the optimum supplementary dose of Se was 0.3 mg/kg dietary DM from SS in dairy bulls.

In vitro effects of sodium bicarbonate buffer on rumen fermentation, levels of lipopolysaccharide and biogenic amine, and composition of rumen microbiota.

BACKGROUND: Diets containing high levels of carbohydrates provoke a rapid decrease of rumen pH and high levels of biogenic amines and lipopolysaccharides (LPS), which severely impair the health and performance of ruminants. The goal of this study was to evaluate the effects of sodium bicarbonate (BC) buffer on rumen fermentation, levels of LPS and biogenic amine, and composition of rumen microbiota using in vitro rumen cultures. RESULTS: Sodium bicarbonate supplementation increased (P < 0.05) the final pH levels and concentrations of total volatile fatty acids and LPS, as well as the proportions of acetate, propionate, isobutyrate, isovalerate and valerate, and it decreased (P < 0.05) the proportion of butyrate and the levels of lactic acid, methylamine, tryptamine, tyramine, histamine and putrescine compared with the control. Pyrosequencing of the 16S rRNA gene showed that BC inclusion increased (P < 0.05) the bacterial diversity index compared with the control. Adding BC also decreased (P < 0.05) the relative abundance of Streptococcus and Butyrivibrio and increased (P < 0.05) the proportions of Ruminococcus, Succinivibrio and Prevotella. CONCLUSION: Sodium bicarbonate supplementation has beneficial effects in the reduction of bioamine levels and the increase in ruminal pH, and in modifying the microbial ecology of the rumen; however, it results in an accumulation of LPS under high-grain diet conditions. © 2016 Society of Chemical Industry.

Microbiome-metabolome analysis reveals unhealthy alterations in the composition and metabolism of ruminal microbiota with increasing dietary grain in a goat model.

Currently, knowledge about the impact of high-grain (HG) feeding on rumen microbiota and metabolome is limited. In this study, a combination of the 454 pyrosequencing strategy and the mass spectrometry-based metabolomics technique was applied to investigate the effects of increased dietary grain (0%, 25% and 50% maize grain) on changes in whole ruminal microbiota and their metabolites using goat as a ruminant model. We observed a significant influence of HG feeding in shaping the ruminal bacterial community structure, diversity and composition, with an overall dominance of bacteria of the phylum Firmicutes along with a low abundance of Bacteriodetes in the HG group. High-grain feeding increased the number of ciliate and methanogens, and decreased the density of anaerobic fungi and the richness of the archaeal community. The metabolomics analysis revealed that HG feeding increased the levels of several toxic, inflammatory and unnatural compounds, including endotoxin, tryptamine, tyramine, histamine and phenylacetate. Correlation analysis on the combined datasets revealed some potential relationships between ruminal metabolites and certain microbial species. Information about these relationships may prove useful in either direct (therapeutic) or indirect (dietary) interventions for ruminal disorders due to microbial compositional shifts, such as ruminal acidosis.

Effects of dietary supplementation of rumen-protected folic acid on rumen fermentation, degradability and excretion of urinary purine derivatives in growing steers.

The present experiment was undertaken to determine the effects of dietary addition of rumen-protected folic acid (RPFA) on ruminal fermentation, nutrient degradability, enzyme activity and the relative quantity of ruminal cellulolytic bacteria in growing beef steers. Eight rumen-cannulated Jinnan beef steers averaging 2.5 years of age and 419 ± 1.9 kg body weight were used in a replicated 4 × 4 Latin square design. The four treatments comprised supplementation levels of 0 (Control), 70, 140 and 210 mg RPFA/kg dietary dry matter (DM). On DM basis, the ration consisted of 50% corn silage, 47% concentrate and 3% soybean oil. The DM intake (averaged 8.5 kg/d) was restricted to 95% of ad libitum intake. The intake of DM, crude protein (CP) and net energy for growth was not affected by treatments. In contrast, increasing RPFA supplementation increased average daily gain and the concentration of total volatile fatty acid and reduced ruminal pH linearly. Furthermore, increasing RPFA supplementation enhanced the acetate to propionate ratio and reduced the ruminal ammonia N content linearly. The ruminal effective degradability of neutral detergent fibre from corn silage and CP from concentrate improved linearly and was highest for the highest supplementation levels. The activities of cellobiase, xylanase, pectinase and α-amylase linearly increased, but carboxymethyl-cellulase and protease were not affected by the addition of RPFA. The relative quantities of Butyrivibrio fibrisolvens, Ruminococcus albus, Ruminococcus flavefaciens and Fibrobacter succinogenes increased linearly. With increasing RPFA supplementation levels, the excretion of urinary purine derivatives was also increased linearly. The present results indicated that the supplementation of RPFA improved ruminal fermentation, nutrient degradability, activities of microbial enzymes and the relative quantity of the ruminal cellulolytic bacteria in a dose-dependent manner. According to the conditions of this experiment, the optimum supplementation level of RPFA was 140 mg/kg DM.

Characterization of bacterial community of raw milk from dairy cows during subacute ruminal acidosis challenge by high-throughput sequencing.

BACKGROUND: Four cannulated primiparous Holstein dairy cows (84 ± 25 DIM) were used in a 2 × 2 crossover experimental design. The two diets contained 40% (low-concentrate diet, or control diet, LC) and 70% (high-concentrate diet, or SARA induction diet, HC) concentrate feeds respectively. Milk samples were collected on days 17, 18 and 19 of each experimental period. DNA was extracted from each milk sample, and pyrosequencing was applied to analyse the milk microbial community. RESULTS: Regardless of diet, the bacterial community of milk was dominated by Actinobacteria, Firmicutes, Proteobacteria and Bacteroidetes. HC feeding showed a higher proportion of some mastitis-causing pathogen bacteria, such as Stenotrophomonas maltophilia, Streptococcus parauberis and Brevundimonas diminuta, as well as of psychrotrophic bacteria, such as Pseudomonas, Brevundimonas, Sphingobacterium, Alcaligenes, Enterobacter and Lactobacillus. However, the diversity of the milk bacterial microbiota (ACE, Chao, and Shannon index) was not affected by HC feeding. CONCLUSION: To the best of our knowledge, this is the first report on the use of pyrosequencing for evaluating the impacts of nutrition on changes in the composition of milk microbiota. These findings indicate that HC feeding may increase the risk of dairy cows suffering from mastitis, decrease the organoleptic quality of raw milk and dairy products, and limit the shelf life of processed fluid milk.

Impact of subacute ruminal acidosis on the diversity of liquid and solid-associated bacteria in the rumen of goats.

This study was aimed to investigate the impact of subacute ruminal acidosis (SARA) on the diversity of liquid (LAB) and solid-associated bacteria (SAB) following high-grain feeding. Six ruminally cannulated goats were divided into two groups: one group was fed a hay diet (COD), and the other group was fed a high grain diet (SAID). Rumen liquids and rumen solids were sampled after 2 weeks adaption. SARA was diagnosed with a pH below 5.8 for 8 h. SAID decreased ruminal pH (P < 0.001) and increased the acetate (P = 0.017), propionate (P = 0.001), butyrate (P < 0.001) and total volatile fatty acid (P < 0.001) concentration in rumen compared with the COD. Denaturing gradient gel electrophoresis fingerprints analysis revealed a clear separation between both the diet and the fraction of rumen digesta in bacterial communities. Pyrosequencing analysis showed that the proportion of phylum Bacteroidetes in the SAID-LAB and SAID-SAB communities was less than in the COD group, whereas the SAID group had a greater percentage of Firmicutes in both the LAB and SAB libraries. UniFrac analyses and a Venn diagram revealed a large difference between the two diets in the diversity of rumen bacterial communities. Overall, our findings revealed that SARA feeding did alter the community structure of rumen liquids and rumen solids. Thus, manipulation of dietary factors, such as ratio of forage to concentrate may have the potential to alter the microbial composition of rumen liquid and rumen solid.

Influences of lauric acid addition on performance, nutrient digestibility and proteins related to mammary gland development in dairy cows.

Lauric acid (LA) has the possibility to improve milk production in dairy cows by improving mammary gland development, however, the mechanism by which it might regulate mammary gland development is unclear. The influence of LA on milk production, nutrient digestibility and the expression of proteins related to mammary gland development in dairy cows were evaluated. Forty primiparous Holstein dairy cows were divided into 4 groups in a randomized block design. Four treatments included the control (0 g/d LA per cow), low-LA (100 g/d LA per cow), medium-LA (200 g/d LA per cow), and high-LA (300 g/d LA per cow). Yields of milk, fat-corrected milk, and energy-corrected milk quadratically increased (P < 0.05), and yield and content of milk fat linearly increased (P < 0.05) with LA supplementation. Percentages of C12:0, C18:1 and C20:1 fatty acids in milk fat linearly increased (P < 0.05), but that of C16:0 fatty acid linearly decreased (P = 0.046). Supplementation of LA led to a linear and quadratical increase (P < 0.05) in digestibility of dry matter, organic matter, neutral detergent fibre and acid detergent fibre, and ruminal total volatile fatty acid concentration but a linear reduction (P = 0.018) in the ratio of acetate to propionate. The enzymatic activities of ruminal pectinase, xylanase, and α-amylase, and populations of total bacteria and anaerobic fungi increased linearly (P < 0.05), while populations of total protozoa and methanogens decreased linearly (P < 0.05) with increased LA addition. Following LA addition, blood glucose, triglyceride, estradiol, prolactin, and insulin-like growth factor 1 concentrations increased linearly (P < 0.05) and albumin and total protein concentrations increased quadratically (P < 0.05). Moreover, addition of 200 g/d LA promoted (P < 0.05) the expression of protein involved in mammary gland development and fatty acids synthesis. These results suggested that LA addition enhanced milk production and fatty acids synthesis by stimulating nutrient digestion, the expression of proteins associated with milk fat synthesis and mammary gland development.