The impact of rumen-protected amino acids on the expression of key- genes involved in the innate immunity of dairy sheep

Rumen protected amino acids inclusion in ewes’ diets has been proposed to enhance their innate immunity. The objective of this work was to determine the impact of dietary supplementation with rumen-protected methionine or lysine, as well as with a combination of these amino acids in two different ratios, on the expression of selected key-genes (NLRs, MyD88, TRIF, MAPK-1, IRF-3, JunD, TRAF-3, IRF-5, IL-1α, IL-10, IKK-α, STAT-3 and HO-1). Thus, sixty Chios dairy ewes (Ovis aries) were assigned to one of the following five dietary treatments (12 animals/ treatment): A: basal diet consist of concentrates, wheat straw and alfalfa hay (control group); B: basal diet +6.0 g/head rumen-protected methionine; C: basal diet + 5.0 g/head rumen-protected lysine; D: basal diet +6.0 g/head rumen-protected methionine + 5.0 g/head rumen-protected lysine and E: basal diet +12.0 g/head rumen-protected methionine + 5.0 g/head rumen-protected lysine. The results revealed a significant downregulation of relative transcript level of the IL-1α gene in the neutrophils of C and in monocytes of D ewes compared with the control. Significantly lower mRNA transcript accumulation was also observed for the MyD88 gene in the neutrophils of ewes fed with lysine only (C). The mRNA relative expression levels of JunD gene were highly induced in the monocytes, while those of IL-10 and HO-1 genes were declined in the neutrophils of ewes fed with the C and D diets compared with the control. Lower transcript levels of STAT-3 gene were observed in the neutrophils of ewes fed with either C or with E diets in comparison with the control. In conclusion, our results suggest that the dietary supplementation of ewes with rumen-protected amino acids, down regulate the expression of some genes involved in the pro-inflammatory signalling.

Production responses to rumen-protected choline and methionine supplemented during the periparturient period differ for primi- and multiparous cows

The objective of this experiment was to examine production performance responses to feeding rumen-protected choline (RPC) or methionine (RPM), or both, during the periparturient period. Fifty-four Holstein cows (25 primiparous, 29 multiparous) were used in a randomized block design experiment with a 2 × 2 factorial treatment structure. Cows were blocked by expected calving date and parity and assigned to 1 of 4 treatments: CON (no RPC or RPM); RPC (13.0 g/d of choline ion); RPM (9 g/d of dl-methionine prepartum; 13.5 g/d of dl-methionine postpartum); or RPC + RPM. Treatments were applied once daily as a top-dress from 3 wk before through 5 wk after calving. Dry matter intake and milk production were recorded daily, and milk samples were obtained once weekly. Data were analyzed for primi- and multiparous cows separately, using a repeated-measures mixed model that included random effects of cow and block and fixed effects of RPC, RPM, week, and their interactions; week served as the repeated effect. Initial BW and previous lactation milk yield were included as covariates in the statistical model for multiparous cows. Feeding RPC without RPM increased milk yield for multiparous cows by 8.7 kg/d, but this increase was not observed when RPC was fed with RPM. In multiparous cows, feeding RPM increased milk fat concentration and tended to increase milk fat yield. Because of this, RPM increased fat-corrected milk (FCM) by 2.8 kg/d at wk 2 postpartum, and this increase was sustained through wk 5 postpartum. In contrast, RPM did not affect overall milk fat yield and concentration for primiparous cows. Feeding RPC increased milk yield for primiparous cows by 3.5 kg/d irrespective of RPM inclusion, which is contrary to observations in multiparous cows, where RPC increased milk yield only in the absence of RPM. These results indicate that responses to RPC during the periparturient period may be dependent upon supply of methionine. Our observations also demonstrate that primi- and multiparous cows respond differently to RPC and RPM supplemented individually or simultaneously during the periparturient period. This variation in response could have been mediated by putative differences in choline and methionine requirements of primiparous versus multiparous cows, or by differences in the levels of milk production between the 2 groups (36 vs. 25 kg of FCM/d). However, cows in this study did not experience severe negative energy balance (mean nadirs of -6.6 and -5.0 Mcal/d for multiparous and primiparous cows, respectively), which likely affected their responses to RPC and RPM.

Symposium review: One-carbon metabolism and methyl donor nutrition in the dairy cow

The present review focuses on methyl donor metabolism and nutrition in the periparturient and lactating dairy cow. Methyl donors are involved in one-carbon metabolism, which includes the folate and Met cycles. These cycles work in unison to support lipid, nucleotide, and protein synthesis, as well as methylation reactions and the maintenance of redox status. A key feature of one-carbon metabolism is the multi-step conversion of tetrahydrofolate to 5-methyltetrahyrofolate. Homocysteine and 5-methyltetrahyrofolate are utilized by vitamin B₁₂-dependent Met synthase to couple the folate and Met cycles and generate Met. Methionine may also be remethylated from choline-derived betaine under the action of betaine hydroxymethyltransferase. Regardless, Met is converted within the Met cycle to S-adenosylmethionine, which is universally utilized in methyl-group transfer reactions including the synthesis of phosphatidylcholine. Homocysteine may also enter the transsulfuration pathway to generate glutathione or taurine for scavenging of reactive oxygen metabolites. In the transition cow, a high demand exists for compounds with a labile methyl group. Limited methyl group supply may contribute to inadequate hepatic phosphatidylcholine synthesis and hepatic triglyceride export, systemic oxidative stress, and compromised milk production. To minimize the perils associated with methyl donor deficiency, the peripartum cow relies on de novo methylneogenesis from tetrahydrofolate. In addition, dietary supplementation of rumen-protected folic acid, vitamin B₁₂, Met, choline, and betaine are potential nutritional approaches to target one-carbon pools and improve methyl donor balance in transition cows. Such strategies have merit considering research demonstrating their ability to improve milk production efficiency, milk protein synthesis, hepatic health, and immune response. This review aims to summarize the current understanding of folic acid, vitamin B₁₂, Met, choline, and betaine utilization in the dairy cow. Methyl donor co-supplementation, fatty acid feeding strategies that may optimize methyl donor supplementation efficacy, and potential epigenetic mechanisms are also considered.

Effects of a novel heat-treated protein and carbohydrate supplement on feed consumption, milk production, and cheese yield in early-lactation dairy cows

Protein is an expensive component of the dairy cow diet, and overfeeding protein can have adverse economic and environmental impacts. Our objective was to maintain milk production and components while decreasing dietary crude protein (CP) through use of a heat-treated, rumen-resistant sugar amino acid complex (SAAC) as the Schiff base, as an addition to low-protein diets. Dietary treatments included a negative control [NC, 146 g of CP/kg of dry matter (DM)], a positive control (PC, 163 g of CP/kg of DM), and the NC supplemented with SAAC in lieu of some barley grain (SAAD, 151 g of CP/kg of DM). Diets were fed to 30 multiparous Holstein-Friesian dairy cows for the first 50 d postpartum. Dry matter intake (DMI) was determined daily. Milk yield and content of fat, protein, lactose, and casein were recorded weekly from wk 2 to 7 of lactation. The fixed effects of treatment, week, treatment × week, month of calving, and BCS at calving, and a random effect of cow, were analyzed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC). The SAAD treatment had greater energy-corrected milk yield than did NC. The PC treatment had greater DMI than did NC, and SAAD tended to have greater DMI than did NC. We found significant treatment effects for fat percentage and yield. The NC and SAAD treatments had higher fat percentages than did PC, and SAAD had a higher fat yield than did the NC and PC treatments. Treatment effects were found for casein yield and percentage. We discovered a treatment effect for protein percentage and yield. The PC treatment had higher protein percentage than did NC and SAAD. The PC treatment had a higher protein yield than did NC, and analysis revealed no difference in protein yield between PC and SAAD. The SAAD treatment had higher total milk solids than did the NC treatment. Lactose yield tended to be higher in PC than in NC, and no differences were found between PC and NC and SAAD treatments. The PC treatment had a higher casein percentage than did NC and SAAD; however, the SAAD and PC treatments had higher casein yields than did NC. The PC treatment had a higher casein:fat ratio than did the NC and SAAD treatments. The NC and SAAD treatments had higher Cheddar cheese yields than did PC. We found no treatment × week interactions for any parameter. Supplementing low-protein dairy cow diets with a heat-treated, rumen-resistant SAAC caused beneficial effects by improving milk components and increasing cheese yield to levels similar to those found when feeding expensive and environmentally damaging high-protein diets.

Effects of rumen-protected methionine on lactation performance and physiological variables during a heat stress challenge in lactating Holstein cows

Milk yield, content, and composition are altered by heat stress. Thirty-two multiparous, lactating Holstein cows [balanced by days in milk (mean ± standard deviation; 184 ± 59); body surface area (5.84 ± 0.34 m²)] were randomly assigned to 1 of 2 dietary treatments [total mixed ration with rumen-protected Met (RPM; Smartamine M; Adisseo Inc., Antony, France; 1.05 g of RPM/kg of dry matter intake) or total mixed ration without RPM (CON)], and within each dietary treatment group cows were randomly assigned to 1 of 2 environmental treatment groups in a split-plot crossover design. The study was divided into 2 periods with 2 phases per period. In phase 1 (9 d), all cows were in thermoneutral conditions and fed ad libitum. In phase 2 (9 d), group 1 (n = 16) was exposed to a heat stress challenge (HSC) using electric heat blankets. Group 2 (n = 16) remained in thermoneutral conditions but was pair-fed (PFTN) to HSC counterparts. After a 21-d washout period, the study was repeated (period 2) and the environmental treatments were inverted relative to treatments from phase 2 of period 1, whereas dietary treatments (RPM or CON) remained the same for each cow. Cows were milked 3× per day and samples were taken on d 1, 5, and 9 of each phase. Vaginal temperature was measured every 10 min, rectal temperature and skin temperature were measured 3× per day, and respiration rate and heart rate were recorded once per day. Cow activity was measured using an accelerometer. Paired difference values were calculated for each cow for each period based on the difference between phase 1 baseline means and phase 2 values for each variable. Cows in HSC had a greater increase in vaginal temperature and respiration rate (+0.2°C and +13.7 breaths/min, respectively) compared with cows in PFTN (0.0°C and -1.6 breaths/min, respectively). Cows in PFTN had a greater decrease in dry matter intake and milk yield (-3.9 and -2.6 kg/d, respectively) compared with cows in HSC (-3.2 and -0.9 kg/d, respectively). Cows in CON had a greater decrease in milk protein concentration for PFTN (-0.10 percentage units) and HSC (-0.06 percentage units) compared with cows in RPM for PFTN (0.00 percentage units) and HSC (-0.02 percentage units). Cows in CON for HSC had greater decrease in milk fat concentration compared with cows in RPM for HSC (-0.10 and +0.12 percentage units, respectively). In conclusion, HSC altered physiological and production parameters of cows. Additionally, RPM helped maintain milk protein and fat concentration during HSC, whereas dry matter intake, milk yield, and feed efficiencies were not affected by RPM.

Supply of methionine and arginine alters phosphorylation of mechanistic target of rapamycin (mTOR), circadian clock proteins, and α-s1-casein abundance in bovine mammary epithelial cells

Methionine (Met) and arginine (Arg) regulate casein protein abundance through alterations in activity of the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway.

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.

Meta-analysis of the effects of supplemental rumen-protected choline during the transition period on performance and health of parous dairy cows

The objectives were to use meta-analytic methods to determine the effects of amount of supplemental choline ion as rumen-protected choline (RPC) starting prepartum on production and health of dairy cows. The literature was systematically reviewed and 21 experiments, with up to 66 treatment means and 1,313 prepartum parous cows, were included. All experiments had a treatment with no supplemental choline (0 g/d; n = 30 treatment means), and the amount of choline ion supplemented to treated cows ranged from 5.6 to 25.2 g/d (n = 36 treatment means). Duration of pre- and postpartum feeding of RPC averaged (±standard deviation) 22.0 ± 6.0 and 57.5 ± 42.2 d, respectively. Data collected included the ingredient composition and chemical analyses of pre- and postpartum diets, amount of choline ion supplemented, number of cows per treatment, frequency of health events, and the least squares means and respective standard error of the means for production responses, liver composition, and blood parameters. The concentrations of net energy for lactation and metabolizable amino acids and protein (MP) in pre- and postpartum diets were predicted for each treatment mean using National Research Council (2001). Mixed model meta-analysis was conducted including the random effect of experiment and weighting by the inverse of the standard error of the means squared. Increasing supplementation of choline ion during transition linearly increased pre- (β = 0.0184 ± 0.00425) and postpartum dry matter intake (β = 0.0378 ± 0.00974), and yields of milk (β = 0.436 ± 0.112), energy-corrected milk (ECM; β = 0.422 ± 0.0992), fat (β = 0.00555 ± 0.000793), and protein (β = 0.0138 ± 0.00378). Nevertheless, an interaction between choline and postpartum metabolizable methionine as a percent of MP (METMPPo) was observed for yields of milk, ECM, and protein because as METMPPo increased, the positive response to choline on yields of milk, ECM, and protein decreased. Supplementing choline during transition tended to reduce the risks of retained placenta and mastitis, but it had no effect on metritis, milk fever, displaced abomasum and ketosis, or the concentration of triacylglycerol in the hepatic tissue postpartum. The median amount of choline ion supplemented was 12.9 g/d and responses in postpartum dry matter intake and yields of milk, ECM, fat, and protein to that amount of supplementation were 0.5, 1.6, 1.7, 0.07, and 0.05 kg/d, respectively. No interactions were observed between supplemental choline and prepartum dietary net energy for lactation or metabolizable methionine as a percent of MP. Collectively, feeding RPC during the transition period improves performance in parous cows. Increases in yields of milk and milk components were observed in spite of pre- and postpartum diets, although the increments in milk, ECM, and protein yields with supplementing choline decreased as the concentration of methionine in postpartum diets increased. The optimum dose of choline ion was not detected, but likely it is more than the 12.9 g/d fed in most experiments evaluated in the current meta-analysis. Finally, the meta-analysis identified lack of sufficient data to understand the role of supplemental choline in nulliparous cows.

Hepatic Cystathionine β-Synthase Activity Is Increased by Greater Postruminal Supply of Met during the Periparturient Period in Dairy Cows

BACKGROUND

Postruminal supply of Met during the periparturient period enhances production efficiency (feed conversion to milk) in dairy cows partly through alleviation of oxidant and inflammatory status. Whether alterations in hepatic 1-carbon metabolism (major contributor of antioxidants) and/or energy metabolism contribute to these beneficial effects is unknown.

OBJECTIVES

To investigate alterations in hepatic 1-carbon and energy metabolism and associations with plasma amino acids (AAs) and production efficiency in response to enhanced postruminal supply of Met.

METHODS

Holstein cows (n = 30 per group) were fed during the last 28 d of pregnancy a control diet (CON) or the control plus ethylcellulose rumen-protected Met (MET; 0.9 g/kg of dry matter intake). Plasma (n = 15 per group) and liver tissue (n = 10 per group) were collected throughout the periparturient period to evaluate AA profiles, activity of the tricarboxylic acid cycle, and 1-carbon metabolism via mRNA abundance, enzyme activity, and targeted metabolomics.

RESULTS

Cows in the MET group had greater overall (27%, P = 0.027) plasma Met concentrations, but had similar total plasma AA concentrations. Although mRNA abundance of 1-carbon metabolism enzymes did not differ, hepatic activity of cystathionine β-synthase (CBS) (51.2 compared with 44.4 mmol/h/mg protein; P = 0.032) and concentration (19%, P = 0.048) of the cellular antioxidant glutathione were greater overall in the MET group. mRNA abundance of aconitase 2 and fumarate hydratase was greater overall (P = 0.049), and phosphoenolpyruvate carboxykinase 1 tended (P = 0.093) to be greater overall in cows fed MET. There was a tendency (P ≤ 0.093) for greater overall hepatic concentrations of malic acid, α-ketoglutaric acid, and isocitric acid in cows fed MET.

CONCLUSIONS

Greater activity of CBS in response to enhanced postruminal supply of Met likely contributes to alleviating oxidant status by increasing concentrations of glutathione. Hence, transsulfuration plays an important role in the observed improvements in production efficiency of dairy cows during the periparturient period.

Seryl-tRNA synthetase is involved in methionine stimulation of β-casein synthesis in bovine mammary epithelial cells

Despite the well-characterised mechanisms of amino acids (AA) regulation of milk protein synthesis in mammary glands (MG), the underlying specific AA regulatory machinery in bovine MG remains further elucidated. As methionine (Met) is one of the most important essential and limiting AA for dairy cows, it is crucial to expand how Met exerts its regulatory effects on dairy milk protein synthesis. Our previous work detected the potential regulatory role of seryl-tRNA synthetase (SARS) in essential AA (EAA)-stimulated bovine casein synthesis. Here, we investigated whether and how SARS participates in Met stimulation of casein production in bovine mammary epithelial cells (BMEC). With or without RNA interference against SARS, BMEC were treated with the medium in the absence (containing all other EAA and devoid of Met alone)/presence (containing 0·6 mm of Met in the medium devoid of Met alone) of Met. The protein abundance of β-casein and members of the mammalian target of rapamycin (mTOR) and general control nonderepressible 2 (GCN2) pathways was determined by immunoblot assay after 6 h treatment, the cell viability and cell cycle progression were determined by cell counting and propidium iodide-staining assay after 24 h treatment, and protein turnover was determined by l-[ring-3H5]phenylalanine isotope tracing assay after 48 h treatment. In the absence of Met, there was a general reduction in cell viability, total protein synthesis and β-casein production; in contrast, total protein degradation was enhanced. SARS knockdown strengthened these changes. Finally, SARS may work to promote Met-stimulated β-casein synthesis via affecting mTOR and GCN2 routes in BMEC.

Effects of supplementing rumen-protected lysine and methionine during prepartum and postpartum periods on performance of dairy cows

An experiment was conducted to examine effects of prepartum, postpartum, or continuous prepartum and postpartum supply of rumen-protected lysine (RPLys) and rumen-protected methionine (RPMet) on performance and blood metabolites of transition cows. The experiment consisted of a prepartum (3 wk), postpartum (3 wk), and carryover (10 wk) period. Eighty-eight prepartum cows (36 primiparous and 52 multiparous cows) were blocked by parity and expected calving date and assigned to 1 of 4 treatments arranged factorially. Treatments were a prepartum diet (12% crude protein on a dry matter basis) without (Pre-) or with supplemental RPLys (10 g of digestible Lys/cow per day) and RPMet (4 g of digestible Met/cow per day; Pre+) followed by postpartum diets (16% crude protein on a dry matter basis) without (Post-) or with supplemental RPLys (26 g of digestible Lys/cow per day) and RPMet (11 g of digestible Met/cow per day; Post+). Prepartum, only 2 treatments were applied, but postpartum cows received treatments of Pre-Post-, Pre-Post+, Pre+Post-, or Pre+Post+. During the prepartum period, treatment did not affect dry matter intake and body weight. During the postpartum period, milk protein content was greater (3.23 vs. 3.11%) for Post+ compared with Post- independent of prepartum treatment. However, dry matter intake, body weight, milk yield, and yields of milk components were not affected by Post+ versus Post-. No effects of prepartum treatment or interactions between pre- and postpartum treatments were observed on postpartum performance of cows. No effects of pre- and postpartum supplementation of RPLys and RPMet on performance during the carryover period were found except prepartum supplementation of RPLys and RPMet decreased somatic cell count (4.60 vs. 4.83; log₁₀ transformed) compared with Pre- in the postpartum period and this effect continued during the carryover period [i.e., 4.42 and 4.55 (log₁₀ transformed) for Pre+ and Pre-, respectively]. Prepartum supplementation of RPLys and RPMet increased or tended to increase plasma concentration of Lys, Met, and branched-chain AA compared with Pre- in prepartum cows. Cows on Post+ tended to have greater plasma Lys concentration compared with Post-, but plasma Met concentration was not affected. Health events of postpartum cows were not affected by treatments. In conclusion, we did not observe positive effects of supplementing with RPLys and RPMet on performance of prepartum and postpartum cows. However, prepartum supply of RPLys and RPMet may have potential to improve udder health and immune status of fresh cows.

Supply of Methionine During Late-Pregnancy Alters Fecal Microbiota and Metabolome in Neonatal Dairy Calves Without Changes in Daily Feed Intake

To our knowledge, most studies demonstrating the role of manipulating maternal nutrition on hindgut (i.e., large intestine) microbiota in the offspring have been performed in non-ruminants. Whether this phenomenon exists in cattle is largely unknown. Therefore, the objectives of the current study were to evaluate the impact of maternal post-ruminal supply of methionine during late-pregnancy in dairy cows on fecal microbiota and metabolome in neonatal calves, and their association with body development and growth performance during the preweaning period. To achieve this, heifer calves, i.e., neonatal female offspring, born to Holstein cows receiving either a control (CON) diet (n = 13) or CON plus rumen-protected methionine (MET; Evonik Nutrition & Care GmbH) during the last 28 days of pregnancy were used. Fecal samples from heifers were collected from birth until 6 weeks of age, i.e., the preweaning period. Fecal microbiota was analyzed with QIIME 2 whereas fecal metabolites were measured using an untargeted LC-MS approach. At birth, MET heifers had greater (P ≤ 0.05) BW, HH, and WH. During the preweaning period, no differences between groups were detected for starter intake (P = 0.77). However, MET heifers maintained greater (P ≤ 0.05) BW, HH and tended (P = 0.06) to have greater WH and average daily gain (ADG) (P = 0.10). Fecal microbiota and metabolome profiles through 42 days of age in MET heifers indicated greater capacity for hindgut production of endogenous antibiotics and enhanced hindgut functionality and health. Enhancing maternal post-ruminal supply of methionine during late-gestation in dairy cows has a positive effect on hindgut functionality and health in their offspring through alterations in the fecal microbiota and metabolome without affecting feed intake. Those alterations could limit pathogen colonization of the hindgut while providing essential nutrients to the neonate. Together, such responses contribute to the ability of young calves to achieve better rates of nutrient utilization for growth.

Invited review: Management strategies capable of improving the reproductive performance of heat-stressed dairy cattle

Impaired fertility during periods of heat stress is the culmination of numerous physiological responses to heat stress, ranging from reduced estrus expression and altered follicular function to early embryonic death. Furthermore, heat-stressed dairy cattle exhibit a unique metabolic status that likely contributes to the observed reduction in fertility. An understanding of this unique physiological response can be used as a basis for improving cow management strategies, thereby reducing the negative effects of heat stress on reproduction. Potential opportunities for improving the management of dairy cattle during heat stress vary greatly and include feed additives, targeted cooling, genetic selection, embryo transfer and, potentially, crossbreeding. Previous studies indicate that dietary interventions such as melatonin and chromium supplementation could alleviate some of the detrimental effects of heat stress on fertility, and that factors involved in the methionine cycle would likely do the same. These supplements, particularly chromium, may improve reproductive performance during heat stress by alleviating insulin-mediated damage to the follicle and its enclosed cumulus-oocyte complex. Beyond feed additives, some of the simplest, yet most effective strategies involve altering the timing of feeding and cooling to take advantage of comparatively low nighttime temperatures. Likewise, expansion of cooling systems to include breeding-age heifers and dry cows has significant benefits for dams and their offspring. More complicated but promising strategies involve the calculation of breeding values for thermotolerance, the identification of genomic markers for heat tolerance, and the development of bedding-based conductive cooling systems. Unfortunately, no single approach can completely rescue the fertility of lactating dairy cows during heat stress. That said, region-appropriate combinations of strategies can improve reproductive measures to reasonable levels.

Hepatic 1-carbon metabolism enzyme activity, intermediate metabolites, and growth in neonatal Holstein dairy calves are altered by maternal supply of methionine during late pregnancy

Maternal supply of methyl donors such as methionine (Met) during late pregnancy can affect offspring growth and development. The objective was to investigate the effect of postruminal Met supply during late pregnancy on 1-carbon, Met cycle, and transsulfuration pathways in the calf liver. During the last 28 d of pregnancy, cows were individually fed a control diet or the control diet plus rumen-protected dl-Met (MET; 0.09% dry matter intake). Liver samples obtained from calves (n = 14/group) at 4, 14, 28, and 50 d of age were used for metabolomics, real-time PCR, and enzyme activity analyses. Genes associated with 1-carbon metabolism, DNA methylation, and the cytidine 5'-diphosphocholine-choline pathway were analyzed via real-time PCR. Activity of betaine homocysteine methyltransferase, cystathionine β-synthase, and 5-methyltetrahydrofolate homocysteine methyltransferase (MTR) was analyzed using ¹⁴C isotopes. Data were analyzed using a mixed model that included the fixed effects of maternal treatment, day, and their interaction, and the random effect was calf within maternal diet. Calves born to dams offered MET tended to have greater birth body weight and had overall greater body weight during the first 9 wk of life. However, no differences were detected for daily feed intake and average daily gain between groups. Concentrations of betaine and choline, reflecting Met cycle activity, at d 14 through 28 were greater in MET calves. Transsulfuration pathway intermediates also were altered in MET calves, with concentrations of cysteine sulfinic acid and hypotaurine (d 4 and 14) and taurine being greater (d 4, 14, 28, and 50). Despite the lack of differences in daily feed intake, the greater concentrations of the tricarboxylic acid cycle intermediates fumarate and glutamate along with NAD/NADH in MET calves indicated enhanced rates of energy metabolism. Although activity of betaine homocysteine methyltransferase was greater in MET calves at d 14, cystathionine β-synthase was lower and increased at d 14 and 28, where it was greater compared with the control diet. Activity of MTR was lower at d 4 and 50 in MET calves. Among gene targets measured, MET calves had greater overall expression of MTR, phosphatidylethanolamine N-methyltransferase, and choline kinase α and β. An interaction of maternal diet by time was detected for mRNA abundance of DNA methyltransferase 3α (involved in de novo methylation) due to greater values at d 4 and 14 in MET calves. Overall, the data indicate that enhanced postruminal supply of Met to cows during late pregnancy may program hepatic metabolism of the calf in the context of maintaining Met homeostasis, phosphatidylcholine and taurine synthesis, DNA methylation, and energy metabolism. These alterations potentially result in better efficiency of nutrient use, hence conferring the calf a physiologic advantage during a period of rapid growth and development. The precise biologic mechanisms remain to be established.

Beneficial effects of rumen-protected methionine on nitrogen-use efficiency, histological parameters, productivity and reproductive performance of ruminants

Providing essential amounts of balanced nutrients is one of the most vital aspects of livestock production. Among nutrients, protein has an essential role in many physiological functions of animals. Amino acids in needs for both high and medium yielding ruminant animals are not fully covered by microbial degraded feed sources in the rumen of animals, and they must be met by protecting the proteins from being broken down in the rumen; hence, the dietary supplementation of rumen-protected proteins (RPP), including mainly rumen-protected methionine (RPM), became imperative. Many researchers are interested in studying the role of (RPM) in ruminant animals concerning its effect on milk yield, growth performance, digestibility, dry matter intake and nitrogen utilization efficiency. Unfortunately, results obtained from several investigations regarding RPM indicated great fluctuation between its useful and useless effects in ruminant nutrition particularly during early and late lactation period; therefore, this review article may be helpful for ruminant farm owners when they decide to supplement RPM in animal's diet. Conclusively, supplementation of RPM often has a balanced positive influence, without any reported negative impact on milk yield, growth performance and blood parameters especially in early lactating ruminant animals and when used with the low crude protein diet.

Short communication: Supply of methionine during late pregnancy enhances whole-blood innate immune response of Holstein calves partly through changes in mRNA abundance in polymorphonuclear leukocytes

The supply of methionine (Met) in late pregnancy can alter mRNA abundance of genes associated with metabolism and immune response in liver and polymorphonuclear leukocytes (PMN) of the neonatal calf. Whether prenatal supply of Met elicits postnatal effects on systemic inflammation and innate immune response of the calf is not well known. We investigated whether enhancing the maternal supply of Met via feeding ethyl-cellulose rumen-protected Met (RPM) was associated with differences in calf innate immune response mRNA abundance in PMN and systemic indicators of inflammation during the first 50 d of life. Calves (n = 14 per maternal diet) born to cows fed RPM at 0.09% of diet dry matter per day (MET) for the last 28 ± 2 d before calving or fed a control diet with no added Met (CON) were used. Blood for biomarker analysis and isolation of PMN for innate immune function assays and mRNA abundance was harvested at birth (before colostrum feeding) and at 7, 21 and 50 d of age. Whole blood was challenged with enteropathogenic bacteria (Escherichia coli 0118:H8) and phagocytosis and oxidative burst of neutrophils and monocytes were quantified via flow cytometry. Although concentration of haptoglobin and activity of myeloperoxidase among calves from both maternal groups increased markedly between 0 and 7 d of age followed by a decrease to baseline at d 21 the responses were lower in MET compared with CON calves. Nitric oxide concentration decreased markedly between 0 and 7 d regardless of maternal group but MET calves tended to have lower overall concentrations during the study. In vitro phagocytosis in stimulated neutrophils increased markedly over time in both CON and MET calves but responses were overall greater in MET calves. Oxidative burst in both neutrophils and monocytes increased over time regardless of maternal treatment. The mRNA abundance of lactate dehydrogenase (LDHA) signal transducer and activator of transcription 3 (STAT3) and S100 calcium binding protein A8 (S100A8) in PMN was overall greater in MET calves. Overall data suggest that increasing the maternal supply of Met during late pregnancy could affect the neonatal calf inflammatory status and innate immune response. Although changes in mRNA abundance could play a role in coordinating the immune response the exact mechanisms merit further study.

A Meta-Analysis on the Impact of the Supplementation of Rumen-Protected Choline on the Metabolic Health and Performance of Dairy Cattle

Simple Summary

During the first weeks of lactation, dairy cows typically experience negative energy balance, leading to the mobilization of energy reserves. This predisposes early lactating cows towards metabolic diseases, such as fatty liver syndrome and ketosis. The supplementation of rumen-protected choline (RPC) is a strategy to restrict negative effects associated with negative energy balance in early lactating cows, but reported effects are inconsistent. This meta-analysis revealed that the supplementation of RPC positively affected dry matter intake, but this effect was associated with increased milk yield, thus without improving energy balance and metabolic profile of the cows.

Abstract

After parturition, cows undergo negative energy balance leading to fat mobilization, predisposing them to fatty liver syndrome and ketosis with major consequences for health and reproduction. Supplementation of rumen-protected choline (RPC) has attracted major research efforts during the last decade, assuming that choline improves liver function by increasing very low-density lipoprotein exportation from the liver, thereby improving metabolic profiles, milk production, and reproduction. However, the effects of RPC on production, health, and reproduction have been inconsistent. Therefore, the aim of this meta-analysis was to evaluate the effects of RPC supplementation, starting from d 20 (± 12.2) ante partum to d 53 (± 31.0) postpartum, on feed intake, milk production performance and metabolic profiles of dairy cows early postpartum. Data analyses from 27 published studies showed an increase in postpartal dry matter intake (from on average 19.1 to 19.9 kg/d; p < 0.01) and milk yield (from on average 31.8 to 32.9 kg/d; p = 0.03) in cows receiving RPC. Milk fat yield and milk protein yield were also increased (p ≤ 0.05), without changing milk protein and fat contents. However, no interactive effects between cow’s milk yield level and RPC-supplementation as well as no dose-dependent effects of RPC supplementation were observed. Supplementing the diet with RPC showed no effects on blood metabolites (non-esterified fatty acids, beta-hydroxybutyrate, glucose, and cholesterol), independent of the milk yield level of the cows. An effect on liver triacylglycerol contents, incidence of ketosis, and mastitis could not be confirmed across all studies included in this meta-analysis. Also, the positive effects of RPC supplementation on reproductive performance were not consistent findings. In conclusion, supplementing RPC in lactating dairy cows showed positive effects on dry matter intake which likely caused the improved milk yield. However, RPC supplementation did not improve the metabolic health status of the cows. As several factors might be related to the responses to RPC, further research is needed to explore the precise mechanisms of RPC action in lactating cows, especially with regards to feed intake improvement and its related metabolic health-promoting potential in early lactating dairy cows.

Supplementing rumen-protected methionine to lactating multiparous dairy cows did not improve reproductive performance

There is evidence that supplementing methionine has positive effects on uterine environment, oocyte quality and embryo development in cattle. Thus, the objective of this study was to evaluate reproductive traits of cows supplemented with rumen‐protected methionine (RPM) during early to mid‐lactation in comparison with an untreated control group (CON). An additional focus was on the effect of puerperal diseases on reproductive performance parameters in RPM‐supplemented group MET and in CON. A total of 1,709 multiparous Holstein‐Friesian cows were enrolled in this field trial conducted on a commercial dairy farm in Slovakia. Cows were allocated at approximately 12 days post‐partum (dpp) to either CON or MET, the latter supplemented with 25.0 g–27.2 g RPM per cow per day incorporated into the total mixed ration (TMR) until leaving the study pen at approximately 140 dpp. The amount of RPM was calculated based on individual feed ingredients analysis and adjusted during the study period when TMR changed. Cows were monitored during the post‐partum period by vaginal examination (day 5 pp), measuring of beta‐hydroxybutyrate in blood (3, 5, and 8 dpp) and by vaginal examination, uterine cytology and measuring of back fat thickness by ultrasound (all at 31 ± 3 dpp).

Compared with CON, cows supplemented with RPM did not show better reproduction performance parameters (first service submission rate, days to first service, conception risk, days open 140). Results from binary logistic regression model for the risk of conception showed that metritis had a significant effect, but the supplementation of methionine had not. Results of Cox regression analysis for the odds of conception within 140 dpp revealed only metritis and clinical endometritis as significant factors. In conclusion, supplementation of RPM had no beneficial effect on reproductive performance in this study farm compared with an untreated control group.

In vitro methionine supplementation during lipopolysaccharide stimulation modulates immunometabolic gene network expression in isolated polymorphonuclear cells from lactating Holstein cows

Methionine (Met) is one of the 2 most limiting amino acids for milk production in dairy cow diets. The accepted "ideal" ratio of lysine (Lys) to Met (L:M) when formulating diets is 3:1. However, blood from cows fed corn silage-based diets without supplemental rumen-protected Met averages approximately 3.6:1 L:M. Recent in vivo research on cattle immunonutrition has revealed that the immune system could benefit from greater Met supply. To study more closely the effects of different L:M ratios, blood polymorphonuclear cells (PMN) were isolated from 5 Holstein cows in mid-lactation (238 ± 20 d postpartum, 33.8 ± 3.8 kg of milk/d; mean ± SD). The PMN were incubated at 3 different levels of L:M (3.6:1, 2.9:1, or 2.4:1) and stimulated with lipopolysaccharide (LPS) at either 0 or 50 μg/mL for 2 h at 37°C. Target genes were associated with cytokines, pathogen recognition, nuclear receptors, killing mechanisms, and Met and glutathione metabolism. Data were subjected to ANOVA using PROC MIXED in SAS, with L:M, LPS, and their interaction as fixed effects. Stimulation with LPS upregulated genes related to cytokines (IL1B, TNF, IL10 and IL6) and nuclear receptors, including nuclear factor kappa B (NFKB1) and glucocorticoid receptor (NR3C1), and downregulated the mRNA abundance of chemokine receptor 1 (CXCR1), lysozyme (LYZ) and glutathione reductase (GSR). A linear decrease was observed in the mRNA abundance of TNF when L:M was decreased. A similar response was observed for interleukin-1 receptor-associated kinase 1 (IRAK1) and NFKB1 abundance in cells stimulated with LPS (linear effect). A linear increase of LYZ mRNA expression as L:M decreased was detected in unstimulated cells. Furthermore, a decrease in L:M led to a linear decrease of superoxide dismutase 1 (SOD1) mRNA abundance in cells challenged with LPS. Overall, LPS challenge triggered the activation of isolated PMN from mid-lactation cows. However, data suggest the use of a shorter incubation time to capture the peak response and not the resolution of the inflammatory response as in the present study. Our results indicate a possible involvement of Met in modulating PMN inflammatory and oxidative stress status and in helping the resolution of inflammation after initial stimulation.

Hepatic betaine-homocysteine methyltransferase and methionine synthase activity and intermediates of the methionine cycle are altered by choline supply during negative energy balance in Holstein cows

Although choline requirements are unknown, enhanced postruminal supply may decrease liver triacylglycerol (TAG) storage and increase flux through the methionine cycle, helping cows during a negative energy balance (NEB). The objective was to investigate effects of postruminal choline supply during NEB on hepatic activity of betaine-homocysteine methyltransferase (BHMT), methionine synthase (MTR), methionine adenosyltransferase, transcription of enzymes, and metabolite concentrations in the methionine cycle. Ten primiparous rumen-cannulated Holstein cows (158 ± 24 d postpartum) were used in a replicated 5 × 5 Latin square design with 4-d treatment periods and 10 d of recovery (14 d/period). Treatments were unrestricted intake with abomasal infusion of water (A0), restricted intake (R; 60% of net energy for lactation requirements to induce NEB) with abomasal infusion of water (R0) or R plus abomasal infusion of 6.25, 12.5, or 25 g/d of choline ion. Liver tissue was collected on d 5 after the infusions ended, blood on d 1 to 5, and milk on d 1 to 4. Statistical contrasts were A0 versus R0 (CONT1) and tests of linear (L), quadratic (Q), and cubic (C) effects of choline dose. Plasma choline increased with R (CONT1) and choline (L). Although R decreased milk yield (CONT1), choline increased milk yield and liver phosphatidylcholine (PC), but decreased TAG (L). No differences were observed in plasma PC or very-low-density lipoprotein concentrations with R or choline. Activity and mRNA abundance of BHMT were greater with R (CONT1) and increased with choline (L). Although activity of MTR was lower with R (CONT1), it tended to increase with choline (L). No effect of R was detected for activity of methionine adenosyltransferase, but it changed cubically across dose of choline. Those responses were associated with linear increases in the concentrations of liver tissue (+13%) and plasma methionine concentrations. The mRNA abundance of CPT1A, SLC22A5, APOA5, and APOB, genes associated with fatty acid oxidation and lipoprotein metabolism, was upregulated by choline (Q). Overall, enhanced supply of choline during NEB increases hepatic activity of BHMT and MTR to regenerate methionine and PC, partly to help clear TAG. The relevance of these effects during the periparturient period merits further research.

Glucose metabolism is differentially altered by choline and methionine in bovine neonatal hepatocytes

Choline and methionine serve essential roles in the liver that may interact with glucose metabolism. Our objectives were to quantify glucose export, cellular glycogen, and expression of genes controlling oxidation and gluconeogenesis in primary bovine neonatal hepatocytes exposed to increasing concentrations of choline chloride (CC) and D,L-methionine (DLM) with or without fatty acids (FA). Primary hepatocytes isolated from 3 Holstein calves were maintained as monolayer cultures for 24 h before treatment with CC (61, 128, 2028, 4528 μmol/L) and DLM (16, 30, 100, 300 μmol/L) with or without a 1 mmol/L FA cocktail in a factorial design. After 24 h, media was harvested to quantify glucose, β-hydroxybutyrate (BHB), and cells harvested to quantify glycogen, DNA, and gene expression. No interactions between CC and DLM were detected. The potential two-way interaction between CC or DLM and FA was partitioned into three contrasts when P ≤ 0.20: linear without FA, linear with FA, difference of slope. Fatty acids did not affect glucose or cellular glycogen but increased pyruvate carboxylase (PC), cytosolic and mitochondrial phosphoenolpyruvate carboxykinase (PEPCKc, PEPCKm), and glucose-6-phosphatase (G6PC) expression. Increasing CC decreased glucose but increased cellular glycogen. Expression of PC and PEPCKc was increased by CC during FA treatment. Increasing DLM did not affect metabolites or PC expression, although PEPCKc was marginally decreased. Methionine did not affect G6PC, while CC had a marginal quadratic effect on G6PC. Oxidative and gluconeogenic enzymes appear to respond to FA in primary bovine neonatal hepatocytes. Increased PC and PEPCKc by CC during FA treatment suggest increased gluconeogenic capacity. Changes in G6PC may have shifted glucose-6-phosphate towards cellular glycogen; however, subsequent examination of G6PC protein is needed. Unaltered PC and marginally decreased PEPCKc suggest increased oxidative capacity with DLM, although BHB export was unaltered. The differential regulation supports unique effects of CC and DLM within bovine hepatocytes.

Choline supply during negative nutrient balance alters hepatic cystathionine β-synthase, intermediates of the methionine cycle and transsulfuration pathway, and liver function in Holstein cows

Although choline requirements for cows are unknown, enhanced postruminal supply may decrease liver triacylglycerol and increase flux through the Met cycle to improve immunometabolic status during a negative nutrient balance (NNB). Our objectives were to investigate the effects of postruminal choline supply during a feed restriction-induced NNB on (1) hepatic activity cystathionine β-synthase and transcription of enzymes in the transsulfuration pathway and Met cycle; (2) hepatic metabolites in the Met cycle and the transsulfuration pathway, bile acids, and energy metabolism; and 3) plasma biomarkers of liver function, inflammation, and oxidative stress. Ten primiparous rumen-cannulated Holstein cows (158 ± 24 d postpartum) were used in a replicated 5 × 5 Latin square design with 4-d treatment periods and 10 d of recovery (14 d/period). Treatments were unrestricted intake with abomasal infusion of water, restricted intake (R; 60% of net energy for lactation requirements) with abomasal infusion of water, or R plus abomasal infusion of 6.25, 12.5, or 25 g/d choline ion. Liver tissue was collected on d 5 after infusions ended, and blood was collected on d 1, 3, and 5. Statistical contrasts were A0 versus R0 (CONT1), R versus the average of choline doses (CONT2), and tests of linear and quadratic effects of choline dose. Activity of cystathionine β-synthase was lower with R (CONT1) and decreased linearly with choline. Hepatic glutathione was not different with R or choline, but taurine tended to be greater with choline (CONT2). Betaine and carnitine were greater with R (CONT1) and further increased with choline (CONT2). Concentrations of NAD⁺ were greater with choline (CONT2). Cholic and glycol-chenodeoxycholic acids were decreased by R and choline, while taurocholic and tauro-chenodeoxycholic acids were not altered. Plasma aspartate aminotransferase and bilirubin were greater with R (CONT1) but decreased with choline (CONT2). Paraoxonase was lower with R and increased with choline (CONT2). Data suggest that enhanced supply of choline during NNB decreases entry of homocysteine to the transsulfuration pathway, potentially favoring remethylation to Met by acquiring a methyl group from betaine. As such, Met may provide methyl groups for synthesis of carnitine. Along with production data indicating that 12.5 g/d choline ion improved milk yield and liver fatty acid metabolism during NNB, the changes in blood biomarkers also suggest a beneficial effect of choline supply on liver function and oxidative stress.

Effects of Dietary Rumen-Protected Betaine Supplementation on Performance of Postpartum Dairy Cows and Immunity of Newborn Calves

Simple Summary

Betaine plays an important role in growth, lactation, protein synthesis, and fat metabolism in animals, but there are few studies on transition dairy cows and newborn calves. The aim of the current study was to evaluate the effects of rumen-protected betaine supplementation from four weeks before expected calving to six weeks postpartum regarding the lactation performance and blood metabolites of dairy cows and immunity of newborn calves. The results suggested that betaine supplementation tended to increase fat mobilization of postpartum dairy cows. Furthermore, compared to the control calves, the betaine calves had greater plasma total protein and globulin concentrations, which indicates that the immunity of the betaine calves might have improved.

Abstract

The objective of this study was to evaluate the effects of rumen-protected betaine supplementation on performance of postpartum dairy cows and immunity of newborn calves. Twenty-four multiparous Holstein dairy cows were randomly divided into the control (CON, n = 12) and rumen-protected betaine (BET, n = 12) groups after blocking by parity and milk yield during the previous lactation cycle. The cows were fed a basal total mixed ration diet without BET (CON) or with BET at 20 g/d per cow (BET) from four weeks before expected calving to six weeks postpartum. The results showed that betaine supplementation had no effect on dry matter intake and milk yield of the cows. The BET cows tended to increase feed efficiency (energy-corrected milk/dry matter intake) and body weight loss postpartum compared to the CON cows. The plasma β-hydroxybutyrate concentrations of the BET cows were greater at d seven after calving than those of the CON cows. Moreover, compared to the CON calves, the BET calves had greater plasma total protein and globulin concentrations. The plasma glucose concentrations of the BET calves tended to decrease relative to CON cows. In conclusion, rumen-protected betaine supplementation from four weeks before expected calving tended to increase fat mobilization of postpartum dairy cows, and might improve the immunity of newborn calves.

Glutathione metabolism and nuclear factor erythroid 2-like 2 (NFE2L2)-related proteins in adipose tissue are altered by supply of ethyl-cellulose rumen-protected methionine in peripartal Holstein cows

Enhancing the supply of rumen-protected Met (RPM) during the peripartum period alleviates inflammation and oxidative stress status in dairy cows. We tested the hypothesis that RPM could increase abundance of genes and proteins related to glutathione (GSH) metabolism and the antioxidant transcription factor nuclear factor erythroid 2-like 2 (NFE2L2) in subcutaneous adipose tissue. Multiparous Holstein cows were fed a basal diet [control prepartum diet = 1.47 Mcal/kg of dry matter (DM) and 15.3% crude protein; control postpartum diet = 1.67 Mcal/kg of DM and 17.7% crude protein] or the control plus ethyl-cellulose RPM at a rate of 0.09 and 0.10% of DM intake before expected calving and after calving, respectively. Sixty cows were assigned to treatments based on parity, previous 305-d milk yield, and body condition score at 28 d from parturition. Diets were fed from -28 to 30 d. Biopsies of subcutaneous adipose tissue collected on d -10, 10, and 30 relative to parturition from 7 cows in each group were used for measuring concentrations of GSH, reactive oxygen species, superoxide dismutase, malondialdehyde, and mRNA and protein abundance (Western blotting). A repeated-measures ANOVA was used for statistics. The statistical model included the random effect of block and fixed effects of treatment, time, and its interaction. There was a diet × time effect for reactive oxygen species due to lower concentrations in Met versus control cows specifically at d -10. Cows fed Met also had lower concentrations of malondialdehyde in subcutaneous adipose tissue. Compared with controls, overall mRNA abundance of the GSH metabolism-related genes cystathionine-β-synthase (CBS), glutamate-cysteine ligase modifier subunit (GCLM), glutathione reductase (GSR), and glutathione peroxidase 1 (GPX1) was greater in cows fed Met. Furthermore, supply of Met resulted in an overall upregulation of protein abundance of glutathione peroxidase (GPX) 1, GPX3, glutathione S-transferase mu 1 (GSTM1), and glutathione S-transferase α 4 (GSTA4), all related to GSH metabolism. There was a diet × time effect for protein abundance of NFE2L2 and its repressor Kelch-like ECH associated protein 1 (KEAP1) due to lower values at 30 d in cows fed Met versus controls. The abundance of phosphorylated NFE2L2 was lower at 30 d in response to Met. Overall, the data suggest that exogenous Met may play a role in activating GSH metabolism and the antioxidant NFE2L2 pathways in subcutaneous adipose tissue.

Phosphorylation of AKT serine/threonine kinase and abundance of milk protein synthesis gene networks in mammary tissue in response to supply of methionine in periparturient Holstein cows

The main objective was to evaluate the effect of increasing the supply of Met around parturition on abundance and phosphorylation of insulin- and mechanistic target of rapamycin complex 1 (mTORC1)-related signaling proteins along with mRNA abundance of milk protein and fat synthesis-related genes in postpartal mammary tissue. A basal control diet (control) or the basal diet plus ethyl-cellulose rumen-protected Met (0.9 g/kg of dry matter intake; Mepron, Evonik Nutrition & Care GmbH, Hanau-Wolfgang, Germany) were fed (n = 30 cows/diet) from d -28 to 60 relative to parturition. Mammary tissue and blood plasma were harvested from the same cows (n = 5/diet) in the control and Met groups at d 21 postpartum for mRNA, protein, and AA analysis. Increasing the supply of Met led to greater milk protein percentage and milk yield along with greater ratio of phosphorylated (p-)AKT to total AKT. The ratio of p-mTORC1 to total mTORC1 did not differ, but ratio of p-RPS6 to total ribosomal protein S6 (RPS6) was lower in response to Met supply. These responses were associated with greater mRNA abundance of the signaling proteins Janus kinase 2 (JAK2) and insulin receptor substrate 1 (IRS1). Greater Met supply also upregulated mRNA abundance of high-affinity cationic (SLC7A1) and sodium-coupled AA transporters (SLC38A1, SLC38A2); leucyl-tRNA (LARS), valyl-tRNA (VARS), and isoleucyl-tRNA synthetases (IARS); glucose transport solute carrier family 2 member 3 (SLC2A1); glucose transport solute carrier family 2 member 3 (SLC2A3); and casein α-s1 (CSN1S1). The mRNA abundance of components of the unfolded protein response, such as x-box binding protein 1 (XBP1) and activating transcription factor 6 (ATF6), were upregulated, and protein phosphatase 1, regulatory subunit 15A (PPP1R15A) was downregulated in response to greater Met supply. Overall, the data suggest that increased dry matter intake, greater phosphorylation status of AKT, upregulation of glucose and AA transporters, and transcripts of tRNases in response to enhanced Met supply might have compensated for a reduction in ribosome biogenesis due to a lower ratio of p-RPS6 to total RPS6. Together, these cellular responses constitute a mechanism whereby Met supply can regulate milk protein synthesis in early lactation.

Amino Acid Metabolism in Dairy Cows and their Regulation in Milk Synthesis

Background:

Reducing dietary Crude Protein (CP) and supplementing with certain Amino Acids (AAs) has been known as a potential solution to improve Nitrogen (N) efficiency in dairy production. Thus understanding how AAs are utilized in various sites along the gut is critical.

Objective:

AA flow from the intestine to Portal-drained Viscera (PDV) and liver then to the mammary gland was elaborated in this article. Recoveries in individual AA in PDV and liver seem to share similar AA pattern with input: output ratio in mammary gland, which subdivides essential AA (EAA) into two groups, Lysine (Lys) and Branchedchain AA (BCAA) in group 1, input: output ratio > 1; Methionine (Met), Histidine (His), Phenylalanine (Phe) etc. in group 2, input: output ratio close to 1. AAs in the mammary gland are either utilized for milk protein synthesis or retained as body tissue, or catabolized. The fractional removal of AAs and the number and activity of AA transporters together contribute to the ability of AAs going through mammary cells. Mammalian Target of Rapamycin (mTOR) pathway is closely related to milk protein synthesis and provides alternatives for AA regulation of milk protein synthesis, which connects AA with lactose synthesis via α-lactalbumin (gene: LALBA) and links with milk fat synthesis via Sterol Regulatory Element-binding Transcription Protein 1 (SREBP1) and Peroxisome Proliferatoractivated Receptor (PPAR).

Conclusion:

Overall, AA flow across various tissues reveals AA metabolism and utilization in dairy cows on one hand. While the function of AA in the biosynthesis of milk protein, fat and lactose at both transcriptional and posttranscriptional level from another angle provides the possibility for us to regulate them for higher efficiency.

Enhanced supply of methionine or arginine alters mechanistic target of rapamycin signaling proteins, messenger RNA, and microRNA abundance in heat-stressed bovine mammary epithelial cells in vitro

Heat stress (HS) causes reductions in milk production, but it is unclear whether this effect is due to reduced number or functional capacity (or both) of mammary cells. Methionine supplementation improves milk protein, whereas Arg is taken up in excess by mammary cells to produce energy and nonessential AA that can be incorporated into milk protein. To evaluate molecular mechanisms by which mammary functional capacity is affected by HS and Met or Arg, mammary alveolar (MAC-T) cells were incubated at thermal-neutral (37°C) or HS (42°C) temperatures. Treatments were optimal AA profiles (control; Lys:Met = 2.9:1.0; Lys:Arg = 2.1:1.0), control plus Met (Lys:Met = 2.5:1.0), or control plus Arg (Lys:Arg = 1.0:1.0). After incubation for 6 h, cells were harvested and RNA and protein were extracted for quantitative real-time PCR and Western blotting. Protein abundance of mechanistic target of rapamycin (MTOR), eukaryotic initiation factor 2a, serine-threonine protein kinase (AKT), 4E binding protein 1 (EIF4EBP1), and phosphorylated EIF4EBP1 was lower during HS. The lower phosphorylated EIF4EBP1 with HS would diminish translation initiation and reduce protein synthesis. Both Met and Arg had no effect on MTOR proteins, but the phosphorylated EIF4EBP1 decreased by AA, especially Arg. Additionally, Met but not Arg decreased the abundance of phosphorylated eukaryotic elongation factor 2, which could be positive for protein synthesis. Although HS upregulated the heat shock protein HSPA1A, the apoptotic gene BAX, and the translation inhibitor EIF4EBP1, the mRNA abundance of PPARG, FASN, ACACA (lipogenesis), and BCL2L1 (antiapoptotic) decreased. Greater supply of Met or Arg reversed most of the effects of HS occurring at the mRNA level and upregulated the abundance of HSPA1A. In addition, compared with the control, supply of Met or Arg upregulated genes related to transcription and translation (MAPK1, MTOR, SREBF1, RPS6KB1, JAK2), insulin signaling (AKT2, IRS1), AA transport (SLC1A5, SLC7A1), and cell proliferation (MKI67). Upregulation of microRNA related to cell growth arrest and apoptosis (miR-34a, miR-92a, miR-99, and miR-184) and oxidative stress (miR-141 and miR-200a) coupled with downregulation of fat synthesis-related microRNA (miR-27ab and miR-221) were detected with HS. Results suggest that HS has a direct negative effect on synthesis of protein and fat, mediated in part by coordinated changes in mRNA, microRNA, and protein abundance of key networks. The positive responses with Met and Arg raise the possibility that supplementation with these AA during HS might have a positive effect on mammary metabolism.

Methionine Supply During Late-Gestation Triggers Offspring Sex-Specific Divergent Changes in Metabolic and Epigenetic Signatures in Bovine Placenta

Background

Nonruminant male and female offspring respond differently to gestational nutrition, with placenta contributing to the underlying mechanisms. However, similar data are lacking in large ruminants.

Objectives

The aim of this study was to investigate the impact of methionine supply during late-gestation on metabolism and DNA methylation in placenta from cows carrying male or female calves.

Methods

During the last 28 d of pregnancy, cows were individually fed a control diet (CON) or the control diet plus rumen-protected d,l-methionine (MET; 0.9 g/kg dry matter intake). Placentomes collected at term were classified according to cow dietary treatment and offspring sex as follows: Male CON (n = 7), Male MET (n = 7), Female CON (n = 8), and Female MET (n = 8). Calf growth was measured until 9 wk of age. Targeted metabolomics, RT-PCR, global DNA methylation, and activity of selected enzymes in one-carbon metabolism and transsulfuration pathways were performed. Statistics were conducted via ANOVA using MIXED models.

Results

At birth, Male MET calves were heavier than Male CON calves (7.6%, P = 0.02), but body mass was similar at 9 wk of age. In contrast, compared with Female CON, Female MET calves had greater body mass at 9 wk of age (6.3%, P = 0.03). Compared with Male CON, placenta from Male MET calves had greater concentrations of tricarboxylic acid (TCA) cycle and transsulfuration intermediates (23-100%, P < 0.05), along with greater 5-methyltetrahydrofolatehomocysteine methyltransferase activity (67%, P = 0.03). Compared with Female CON, placenta from Female MET calves had greater concentrations of one-carbon metabolism intermediates (13-52%, P < 0.05). DNA methyltransferase 3A (DNMT3A) was upregulated (43%, P < 0.01) in placenta from Female MET compared with Female CON calves. Global DNA methylation was lower in placenta from Female MET compared with Female CON calves (45%, P = 0.06).

Conclusions

Methionine supply affects placental metabolism, DNA methylation, and body mass of the calf in a sex-specific manner, underscoring its importance as dietary methyl-donor for pregnant cows.

Rumen-protected methionine in cattle: influences on reproduction, immune response, and productive performance

ABSTRACT: Nowadays, information and knowledge generated about the main ingredients used in cattle diets have enabled greater assertiveness in their formulation. Among the ingredients, amino acids stand out as a promising tool, capable of reducing total crude protein (CP) levels and adjusting optimal metabolizable protein concentrations in diets. Nutritional programs allow diets due to amino acid requirements, providing the opportunity to increase the efficiency of the use of dietary nitrogen, increasing the scarce protein concentrates, maintaining or even boosting performance. This review aimed to present the influences of methionine, in its formulation protected from ruminal degradation, according to reproductive parameters, immune response, and productive performance in cattle. Reproduction-related benefits are linked to the early days of embryonic implantation in the uterine environment, which initially secretes through the histotroph produced by endometrial glands, the nutrients needed to develop the conceptus until implantation, and vascular communication with the mother. Given the immune response, the main results are related to the benefits of innate immunity, with marked increase in phagocytic capacity of neutrophils and monocytes, as well as an important antioxidant effect mediated by methionine products, such as glutathione. When evaluating the influences on productivity, the most evident correlation is the increase in protein in the milk of cows supplemented with methionine. Over the past decade, studies investigating the potential benefits of this strategic supplementation in beef cattle were intensified, expanding the opportunities for the development of new experimental projects.

Maternal supply of methionine during late-pregnancy enhances rate of Holstein calf development in utero and postnatal growth to a greater extent than colostrum source

Background

Pregnancy and early life are critical periods of plasticity during which the fetus and neonate may be influenced by environmental factors such as nutrition. Maternal methionine (Met) supply in non-ruminants during pregnancy can affect offspring development and growth. Thus, the objective of this study was to investigate if increasing Met supply during late-pregnancy affects developmental parameters of the calf at birth and if either maternal Met or colostrum from Met-fed cows alters calf growth. Calves born to Holstein cows individually-fed a basal control [CON; 1.47 Mcal/kg dry matter (DM) and 15.3% crude protein] diet with no added Met or CON plus ethylcellulose rumen-protected Met (MET; Mepron® at 0.09% of diet DM; Evonik Nutrition & Care GmbH, Germany) during the last 28 ± 2 d of pregnancy were used. A total of 39 calves were in CON (n = 22 bulls, 17 heifers) and 42 in MET (n = 20 bulls, 22 heifers). At birth, calves were randomly allocated considering dam treatment and colostrum as follows: 1) calves from CON cows and colostrum from CON cows (n = 21); 2) calves from CON cows and colostrum from MET cows (n = 18); 3) calves from MET cows and colostrum from MET cows (n = 22); and 4) calves from MET cows and colostrum from CON cows (n = 20). All calves were housed, managed, and fed individually during the first 9 wk of life.

Results

Despite greater daily DM intake pre-partum in cows fed MET (15.7 vs. 14.4 ± 0.12 kg/d, P < 0.05), colostrum quality and quantity were not affected by maternal diet. At birth, MET calves had greater (P ≤ 0.05) body weight (BW, 44.1 vs. 42.1 ± 0.70 kg), hip height (HH, 81.3 vs. 79.6 ± 0.53 cm) and wither height (WH, 77.8 vs. 75.9 ± 0.47 cm). In contrast, concentrations of His, Lys, and Asn in plasma were lower (P ≤ 0.05) in MET calves. Regardless of colostrum source, the greater BW, HH, and WH in MET calves at birth persisted through 9 wk of age resulting in average responses of + 3.1 kg BW, + 1.9 cm HH, and + 1.8 cm WH compared with CON. Average daily gain during the 9 wk was (P < 0.05) 0.72 ± 0.02 kg/d in MET compared with 0.67 ± 0.02 kg/d in CON calves. Respiratory scores were normal and did not differ (P > 0.05) due to maternal Met supply or colostrum source. However, fecal scores tended to be lower (P ≤ 0.10) in MET calves regardless of colostrum source.

Conclusions

Increasing the maternal supply of MET during late-pregnancy enhanced growth in utero as well as during the pre-weaning and early post-weaning periods. Although the ~ 1 kg/d greater DM intake during the last 2-3 wk prior to parturition could explain a portion of the 2 kg extra body mass of MET calves at birth, other mechanisms potentially encompassing nutrient assimilation efficiency likely played a role. Assessing the exact mechanisms sensitive to supply of Met or total amino acid supply during the latter stages of growth in utero merit further research.

Methyl donor supplementation suppresses the progression of liver lipid accumulation while modifying the plasma triacylglycerol lipidome in periparturient Holstein dairy cows

Co-supplementation of methyl donors may lower hepatic lipid content in transition cows. To define the ability of methyl donor supplementation (MDS) to reduce hepatic lipid content and modify the plasma lipidome, 30 multiparous Holstein cows (2.04 ± 0.69 lactations; 689 ± 58 kg of body weight; 3.48 ± 0.10 units of body condition score) were fed a ration with or without rumen-protected methyl donors (22 g/d of Met, 10 g/d of choline chloride, 3 g/d of betaine, 96 mg/d of riboflavin, and 1.4 mg/d of vitamin B₁₂) from d -28 before expected calving through d 14 postpartum. Cows were randomly enrolled based on predefined selection criteria (body condition score and parity). Base diets without MDS were formulated for gestation (15.4% crude protein with a predicted Lys-to-Met ratio of 3.25; 1.44 Mcal of net energy for lactation/kg of dry matter) and lactation (16.6% crude protein with a predicted Lys-to-Met ratio of 3.36; 1.64 Mcal of net energy for lactation/kg of dry matter). Blood sampling occurred from d -28 relative to expected calving through d 14 postpartum. Liver tissue was biopsied at d -28 relative to expected calving and on d 5 and 14 postpartum. In addition to routine analyses, serum AA concentrations on d 10 and 12 were quantified using mass spectrometry. Plasma triacylglycerol (TAG) and cholesteryl esters (CE) were qualitatively measured using time-of-flight mass spectrometry. Data were analyzed using a mixed model with repeated measures. Dry matter intake and milk yield were not modified by MDS. The transition from d -28 relative to expected parturition to d 14 postpartum was characterized by increased plasma fatty acid (0.15 to 0.71 mmol/L) and β-hydroxybutyrate (0.34 to 0.43 mmol/L) levels and liver lipid content (3.91 to 9.16%). Methyl donor supplementation increased the serum Met level by 26% and decreased the serum Lys-to-Met ratio by 21% on d 10 and 12, respectively. Moreover, the increase in hepatic lipid content from d 5 through 14 postpartum was suppressed with MDS relative to control (3.57 vs. -0.29%). Dietary MDS modified the TAG and CE lipidome. For example, MDS increased plasma TAG 46:3 (carbon number:double bond) by 116% relative to control cows on d 5 postpartum. Moreover, MDS tended to increase plasma CE 34:6. In contrast, MDS lowered plasma TAG 54:8 by 39% relative to control cows on d 5 postpartum. We concluded that in the absence of gains in dry matter intake and milk and milk protein yields, dietary MDS slows the progression of hepatic lipid accumulation and modifies the plasma TAG lipidome in transition cows.

Methionine and choline supply alter transmethylation, transsulfuration, and cytidine 5'-diphosphocholine pathways to different extents in isolated primary liver cells from dairy cows

Insufficient supply of Met and choline (Chol) around parturition could compromise hepatic metabolism and milk protein synthesis in dairy cows. Mechanistic responses associated with supply of Met or Chol in primary liver cells enriched with hepatocytes (PHEP) from cows have not been thoroughly ascertained. Objectives were to isolate and culture PHEP to examine abundance of genes and proteins related to transmethylation, transsulfuration, and cytidine 5'-diphosphocholine (CDP-choline) pathways in response to Met or Chol. The PHEP were isolated from liver biopsies of Holstein cows (160 d in lactation). More than 90% of isolated cells stained positively for the hepatocyte marker cytokeratin 18. Cytochrome P450 (CYP1A1) mRNA abundance was only detectable in the PHEP and liver tissue compared with mammary tissue. Furthermore, in response to exogenous Met (80 μM vs. control) PHEP secreted greater amounts of albumin and urea. Subsequently, PHEP were cultured with Met (40 μM) or Chol (80 mg/dL) for 24 h. Compared with control or Chol, mRNA and protein abundance of methionine adenosyltransferase 1A (MAT1A) and phosphatidylethanolamine methyltransferase (PEMT) were greater in PHEP treated with Met. The mRNA abundance of S-adenosylhomocysteine hydrolase (SAHH), betaine-homocysteine methyltransferase (BHMT), and sarcosine dehydrogenase (SARDH) was greater in Met-treated PHEP compared with control or Chol. Compared with control, greater expression of 5-methyltetrahydrofolate-homocysteine methyltransferase (MTR), betaine aldehyde dehydrogenase (BADH), and choline dehydrogenase (CHDH) was observed in cells supplemented with Met and Chol. However, Chol led to the greatest mRNA abundance of CHDH. Abundance of choline kinase α (CHKA), choline kinase β (CHKB), phosphate cytidylyltransferase 1 α (PCYT1A), and choline/ethanolamine phosphotransferase 1 (CEPT1) in the CDP-choline pathway was greater in PHEP treated with Chol compared with control or Met. In the transsulfuration pathway, mRNA and protein abundance of cystathionine β-synthase (CBS) was greater in PHEP treated with Met compared with control or Chol. Similarly, abundance of cysteine sulfinic acid decarboxylase (CSAD), glutamate-cysteine ligase, catalytic subunit (GCLC), and glutathione reductase (GSR) was greater in response to Met compared with control or Chol. Overall, these findings suggest that transmethylation and transsulfuration in dairy cow primary liver cells are more responsive to Met supply, whereas the CDP-choline pathway is more responsive to Chol supply. The relevance of these data in vivo merit further study.

A 100-Year Review: Metabolic modifiers in dairy cattle nutrition

The first issue of the Journal of Dairy Science in 1917 opened with the text of the speech by Raymond A. Pearson, president of the Iowa State College of Agriculture, at the dedication of the new dairy building at the University of Nebraska (J. Dairy Sci. 1:4-18, 1917). Fittingly, this was the birth of a new research facility and more importantly, the beginning of a new journal devoted to the sciences of milk production and manufacture of products from milk. Metabolic modifiers of dairy cow metabolism enhance, change, or interfere with normal metabolic processes in the ruminant digestive tract or alter postabsorption partitioning of nutrients among body tissues. Papers on metabolic modifiers became more frequent in the journal around 1950. Dairy farming changed radically between 1955 and 1965. Changes in housing and feeding moved more cows outside, and cows and heifers in all stages of lactation, including the dry period, were fed as a single group. Rations became wetter with the shift to corn silage as the major forage in many rations. Liberal grain feeding met the requirements of high-producing cows and increased production per cow but introduced new challenges; for example, managing and feeding cows as a group. These changes led to the introduction of new strategies that identified and expanded the use of metabolic modifiers. Research was directed at characterizing the new problems for the dairy cow created by group feeding. Metabolic modifiers went beyond feeding the cow and included environmental and housing factors and additives to reduce the incidence and severity of many new conditions and pathologies. New collaborations began among dairy cattle specialties that broadened our understanding of the workings of the cow. The Journal of Dairy Science then and now plays an enormously important role in dissemination of the findings of dairy scientists worldwide that address existing and new technologies.

A 100-Year Review: Protein and amino acid nutrition in dairy cows

Considerable progress has been made in understanding the protein and amino acid (AA) nutrition of dairy cows. The chemistry of feed crude protein (CP) appears to be well understood, as is the mechanism of ruminal protein degradation by rumen bacteria and protozoa. It has been shown that ammonia released from AA degradation in the rumen is used for bacterial protein formation and that urea can be a useful N supplement when lower protein diets are fed. It is now well documented that adequate rumen ammonia levels must be maintained for maximal synthesis of microbial protein and that a deficiency of rumen-degradable protein can decrease microbial protein synthesis, fiber digestibility, and feed intake. Rumen-synthesized microbial protein accounts for most of the CP flowing to the small intestine and is considered a high-quality protein for dairy cows because of apparent high digestibility and good AA composition. Much attention has been given to evaluating different methods to quantify ruminal protein degradation and escape and for measuring ruminal outflows of microbial protein and rumen-undegraded feed protein. The methods and accompanying results are used to determine the nutritional value of protein supplements and to develop nutritional models and evaluate their predictive ability. Lysine, methionine, and histidine have been identified most often as the most-limiting amino acids, with rumen-protected forms of lysine and methionine available for ration supplementation. Guidelines for protein feeding have evolved from simple feeding standards for dietary CP to more complex nutrition models that are designed to predict supplies and requirements for rumen ammonia and peptides and intestinally absorbable AA. The industry awaits more robust and mechanistic models for predicting supplies and requirements of rumen-available N and absorbed AA. Such models will be useful in allowing for feeding lower protein diets and increased efficiency of microbial protein synthesis.

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.

Methionine supply alters mammary gland antioxidant gene networks via phosphorylation of nuclear factor erythroid 2-like 2 (NFE2L2) protein in dairy cows during the periparturient period

The periparturient period is the most critical period during the lactation cycle of dairy cows and is characterized by increased oxidative stress status. The objective of this experiment was to evaluate the effect of supplementing rumen-protected methionine on nuclear factor erythroid 2-like 2 (NFE2L2, formerly NRF2) protein and target gene expression in the mammary gland during the early postpartal period. Multiparous Holstein cows were used in a block design experiment with 30 cows per treatment. Treatments consisting of a basal control diet (control) or the basal diet plus rumen-protected methionine (methionine) were fed from d -28 to 60 relative to parturition. Mammary tissue biopsies were harvested on d 21 postpartum from 5 cows per treatment. Compared with control, methionine increased dry matter intake, milk yield, and milk protein content. Among plasma parameters measured, methionine led to greater methionine and lower reactive oxygen metabolites. Compared with control, methionine supply resulted in greater mRNA abundance of the NFE2L2 target genes glutamate-cysteine ligase catalytic subunit (GCLC), glutamate-cysteine ligase modifier subunit (GCLM), glutathione reductase (GSR), glutathione peroxidase 1 (GPX1), malic enzyme 1 (ME1), ferrochelatase (FECH), ferritin heavy chain 1 (FTH1), and NAD(P) H quinone dehydrogenase 1 (NQO1) in the mammary tissue. In addition, methionine upregulated the mRNA abundance of NFE2L2, NFKB1, MAPK14 and downregulated KEAP1. The ratio of phosphorylated NFE2L2 to total NFE2L2 protein, and total heme oxygenase 1 (HMOX1) protein were markedly greater in response to methionine supply. In contrast, total protein abundance of Kelch-like ECH-associated protein 1 (KEAP1), which sequesters NFE2L2 in the cytosol and reduces its activity, was lower with methionine. Besides the consistent positive effect of methionine supply on systemic inflammation and oxidative stress status, the present data indicate a positive effect also on antioxidant mechanisms within the mammary gland, which are regulated, at least in part, via phosphorylation of NFE2L2 and its target genes. The exact mechanisms for these responses merit further study.

Hepatic phosphorylation status of serine/threonine kinase 1, mammalian target of rapamycin signaling proteins, and growth rate in Holstein heifer calves in response to maternal supply of methionine

The study investigated whether methionine supply during late pregnancy is associated with liver mammalian target of rapamycin (MTOR) pathway phosphorylation, plasma biomarkers, and growth in heifer calves born to cows fed a control diet (CON) or the control diet plus ethylcellulose rumen-protected methionine (MET; 0.09% of dry matter intake) for the last 28 d prepartum. Calves were fed and managed similarly during the first 56 d of age. Plasma was harvested at birth and 2, 7, 21, 42, and 50 d of age and was used for biomarker profiling. Liver biopsies were harvested at 4, 14, 28, and 50 d of age and used for protein expression. Body weight, hip height, hip width, wither height, body length, rectal temperature, fecal score, and respiratory score were measured weekly. Starter intake was measured daily, and average daily gain was calculated during the first 8 wk of age. During the first 7 wk of age, compared with calves in the CON group, calves in the MET group had greater body weight, hip height, wither height, and average daily gain despite similar daily starter intake. Concentration of methionine in plasma was lower at birth but increased markedly at 2 and 7 d of age in MET calves. Plasma insulin, glucose, free fatty acids, and hydroxybutyrate did not differ. A greater ratio of phosphorylated α-serine/threonine kinase (AKT):total AKT protein expression was detected in MET calves, namely due to differences at 4 d of age. The phosphorylated MTOR:total MTOR ratio also was greater in MET calves due to differences at 28 and 50 d (8 d postweaning). The decrease in phosphorylated MTOR:total MTOR between 14 and 28 d in CON calves agreed with the increase in phosphorylated eukaryotic translation initiation factor 4E binding protein 1 (EIF4EBP1):total EIF4EBP1 ratio during the same time frame. The overall expression of phosphorylated ribosomal protein S6 kinase B1 (RPS6KB1):total RPS6KB1 and phosphorylated eukaryotic translation elongation factor 2 (EEF2):total EEF2 was lower in MET calves. Regardless of methionine supply prepartum, there was an 11-fold temporal decrease from 4 to 50 d in phosphorylated AKT:total AKT. Similarly, regardless of methionine supply, there were overall decreases in phosphorylation ratios of AKT, MTOR, RPS6KB1, and eukaryotic translation initiation factor 2A (EIF2A) over time. Data provide evidence of a positive effect of methionine supply during the last month of pregnancy on rates of growth during the first 7 wk of age. Phosphorylation status of some components of the MTOR pathway in neonatal calf liver also was associated with greater maternal supply of methionine. Thus, the data suggest that molecular mechanisms in the liver might be programmed by supply of methionine during late pregnancy. The exact mechanisms coordinating the observed responses remain to be determined.

Improved uterine immune mediators in Holstein cows supplemented with rumen-protected methionine and discovery of neutrophil extracellular traps (NET)

During the transition from prepartum to early lactation, dairy cows often experience negative energy balance (NEB) that may result in reproductive stress and decreased fertility. The objective of this study was to observe the effects of rumen-protected methionine (RPM) on plasma amino acid concentrations, uterine cytology, immunohistochemistry (IHC) of glutathione peroxidase 1 (GPX) and superoxide dismutase 1 (SOD), and to confirm neutrophil extracellular trap (NET) formation. Multiparous Holstein cows (n = 20) were randomly assigned to two treatments starting at 21 d before calving until 73 days in milk (DIM). Treatments were: CON (n = 9, no supplementation, TMR with a Lys:Met = 3.5:1) and MET (n = 11, TMR + Smartamine^® M with a Lys:Met = 2.8:1). Uterine endometrial biopsies, uterine cytology, and blood samples from the coccygeal artery or vein were collected at 15, 30, and 73 DIM. Blood plasma samples were analyzed for amino acids and metabolites. Uterine biopsies were analyzed for NET formation, neutrophil numbers, as well as GPX and SOD by IHC. Additionally, uterine cytology was analyzed for polymorphonuclear neutrophil (PMN) to epithelial cell percentage. Cows in CON had lower methionine plasma concentrations (18.05 ± 2.0 μM) than cows in MET (30.39 ± 1.6 μM). Cows in CON had greater cystine plasma concentrations (3.62 ± 0.3 μM) than cows in MET (2.8 ± 0.3 μM). No treatment differences were observed for SOD or GPX in the endometrium. Cows in CON tended to have a high score for positively immunolabeled GPX cells at 15 DIM than cows in MET. No treatment differences were observed for the percentage of PMN in uterine cytology, number of neutrophils, or extent of NET formation in the endometrium. A treatment by time interaction was observed for PMN percentage and the number of neutrophils: cows in MET tended to have greater PMN percentages than cows in CON at 15 DIM which decreased for subsequent days and cows in MET had greater neutrophil numbers in the endometrium at 30 DIM than cows in CON. In conclusion, dietary supplementation of RPM altered plasma amino acid concentrations and increased neutrophil infiltration in the postpartum period, suggesting improved uterine immunity.

Rumen-protected methionine during the peripartal period in dairy cows and its effects on abundance of major species of ruminal bacteria

Background

Extensive degradation of amino acids in the rumen via microbial deamination decreases the post-ruminal availability of dietary indispensable amino acids. Together with the normal decrease in voluntary dry matter intake (DMI) around parturition in dairy cows, microbial metabolism contributes to a markedly negative balance of indispensable amino acids, including methionine which may be the first-limiting for milk production. The main objective of the current study was to profile changes in major bacterial species with key functions in cellulose and hemicellulose digestion, xylan breakdown, proteolytic action, propionic acid production, lactate utilization and ruminal biohydrogenation in cows supplemented with rumen-protected Methionine (SM; Smartamine M, Adisseo NA, Alpharetta, GA, USA) from −23 through 30 d relative to parturition. Because ~90% of the methionine in SM bypasses the rumen, ~10% of the methionine is released into the rumen and can be utilized by microbes.

Results

As expected, there was an increase in overall DMI after parturition (Day, P < 0.05) during which cows consumed on average 19.6 kg/d versus 13.9 kg/d in the prepartum period. The postpartum diet contained greater concentrations of lipid and highly-fermentable carbohydrate from corn grain, which likely explains the increases in the relative abundance of Anaerovibrio lipolytica, Megasphaera elsdenii, Prevotella bryantii, Selenomonas ruminantium, Streptococcus bovis, and Succinimonas amylolytica. Despite similar DMI prepartum, cows fed SM had greater (Treatment × Day, P < 0.05) abundance prepartum of Fibrobacter succinogenes, Succinimonas amylolytica, and Succinivibrio dextrinosolvens. However, the greater DMI in cows fed SM after parturition (19.6 kg/d versus 13.9 kg/d) was associated with lower abundance of Fibrobacter succinogenes (2.13 × 10⁻³ versus 2.25 × 10⁻⁴) and Selenomonas ruminantium (2.98 × 10⁻¹ versus 4.10 × 10⁻¹). A lower abundance (Day, P < 0.05) was detected on d 20 compared with d −10 for Fibrobacter succinogenes and Succinivibrio dextrinosolvens. The relative abundance of Butyrivibrio proteoclasticus and Eubacterium ruminantium was stable across treatment and time.

Conclusions

In diets with proper balance of rumen-degradable protein and fermentable carbohydrate, the small fraction of Methionine released from the rumen-protected supplement did not seem to compromise growth of major bacterial species in the rumen. In fact, it had a positive effect on 3 major species prepartum when DMI was similar between groups. Because the actual requirements of Methionine (and Lysine, for example) by the cow during the transition period are unknown, it appears warranted to study the rumen microbiome as it relates to supply of rumen-protected amino acids.

Ethyl-cellulose rumen-protected methionine alleviates inflammation and oxidative stress and improves neutrophil function during the periparturient period and early lactation in Holstein dairy cows

The periparturient period is the most critical phase in the productive cycle of dairy cows and is characterized by impairment of the immune system. Our objective was to evaluate the effect of feeding ethyl-cellulose rumen-protected methionine (RPM) starting at d -28 from expected parturition through 60 d in milk on biomarkers of inflammation, oxidative stress, and liver function as well as leukocyte function. Sixty multiparous Holstein cows were used in a block design and assigned to either a control or the control plus ethyl-cellulose RPM (Mepron, Evonik Nutrition & Care GmbH). Mepron was supplied from -28 to 60 d in milk at a rate of 0.09% and 0.10% dry matter during the prepartum and postpartum period. That rate ensured that the ratio of Lys to Met in the metabolizable protein was close to 2.8:1. Blood samples from 15 clinically healthy cows per treatment were collected at d -30, -14, 1, 7, 21, 30, and 60 and analyzed for biomarkers of liver function, inflammation, and oxidative stress. Neutrophil and monocyte function in whole blood was measured in vitro at -14, 1, 7, 21, and 30 d in milk. The statistical model included the random effect of block and fixed effect of treatment, time, and its interaction. Compared with control, ethyl-cellulose RPM increased plasma cholesterol and paraoxonase after parturition. Among the inflammation biomarkers measured, ethyl-cellulose RPM led to greater albumin (negative acute-phase protein) and lower haptoglobin than control cows. Although concentration of IL-1β was not affected by treatments, greater IL-6 concentration was detected in response to ethyl-cellulose RPM. Cows supplemented with ethyl-cellulose RPM had greater plasma concentration of ferric-reducing antioxidant power, β-carotene, tocopherol, and total and reduced glutathione, whereas reactive oxygen metabolites were lower compared with control cows. Compared with control, ethyl-cellulose RPM enhanced neutrophil phagocytosis and oxidative burst. Overall, the results indicate that ethyl-cellulose RPM supply to obtain a Lys-to-Met ratio of 2.8:1 in the metabolizable protein during the periparturient period and early lactation is an effective approach to help mitigate oxidative stress and inflammation as well as enhance liver and neutrophil function in dairy cows.