Effects of Bacillus subtilis PB6 supplementation on production, metabolism, inflammatory biomarkers, and gastrointestinal tract permeability in transition dairy cows.

Objectives were to evaluate the effects of Bacillus subtilis PB6 (BSP) on gastrointestinal tract permeability, metabolism, inflammation, and production parameters in periparturient Holstein cows. Multiparous cows (n = 48) were stratified by previous 305-d mature equivalent milk yield and parity and assigned to 1 of 2 top-dressed dietary treatments 21 d before expected calving through 63 DIM: (1) control (CON; 13 g/d calcium carbonate; n = 24) or (2) BSP (13 g/d BSP; CLOSTAT, Kemin Industries, Des Moines, IA; n = 24). Gastrointestinal tract permeability was evaluated in vivo using the oral paracellular marker chromium (Cr)-EDTA. Effects of treatment, time, and treatment × time were assessed using PROC MIXED of SAS version 9.4 (SAS Institute Inc.). Prepartum dry matter intake (DMI) was unaffected by treatment; however, BSP supplementation decreased postpartum DMI relative to CON (0.7 kg). Milk yield, energy-corrected milk (ECM), fat-corrected milk (FCM), and solids-corrected milk (SCM) increased in BSP cows compared with CON (1.6, 1.8, 1.6, and 1.5 kg, respectively). Decreased DMI and increased production collectively improved feed efficiency of milk yield, ECM, FCM, and SCM for BSP cows (6, 5, 5, and 5%, respectively). No treatment differences were observed for concentrations of milk fat, protein, total solids, somatic cell count, somatic cell score, body weight, or body condition score. Milk urea nitrogen concentrations decreased (5%), whereas milk protein and lactose yield increased (5 and 2%, respectively) with BSP supplementation. Prepartum fecal pH did not differ among treatments; conversely, postpartum fecal pH was increased with BSP supplementation (0.09 pH units). Prepartum fecal dry matter percentage, starch, acetic acid, propionic acid, butyric acid, and ethanol did not differ among treatments. Postpartum concentrations of the aforementioned fecal parameters were also unaffected by treatment, but fecal propionic acid concentration was decreased (24%) in BSP cows relative to CON. Circulating glucose, nonesterified fatty acids, l-lactate, and insulin were similar between treatments both pre- and postpartum. Prepartum ß-hydroxybutyrate (BHB) did not differ between treatments, but postpartum BSP supplementation decreased (21%) circulating BHB relative to CON. Regardless of treatment, inflammatory markers (serum amyloid A and haptoglobin) peaked immediately following parturition and progressively decreased with time, but this pattern was not influenced by treatment. Postpartum lipopolysaccharide binding protein tended to be decreased on d 3 in BSP relative to CON cows (19%). Neither treatment nor time affected Cr-EDTA area under the curve. In summary, supplementing BSP had no detectable effects prepartum, but increased key postpartum production parameters. Bacillus subtilis PB6 consistently increased postpartum fecal pH and decreased fecal propionate concentrations but did not appear to have an effect on gastrointestinal tract permeability.

Effects of cashew nut shell extract supplementation on production, rumen fermentation, metabolism, and inflammatory biomarkers in transition dairy cows.

Cashew nut shell extract (CNSE) is a byproduct of the cashew nut industry, containing bioactive compounds that alter rumen fermentation patterns. Therefore, study objectives were to evaluate the effects of CNSE (59% anacardic acid and 18% cardol) on production, rumen fermentation variables, metabolism, and inflammation in transition dairy cows. A total of 51 multiparous Holstein cows were used in a randomized design and assigned to treatment based on their previous 305-d mature equivalent milk and parity. Cows were assigned to 1 of 2 treatments 21 d before expected calving: (1) CON (control diet; n = 17) or (2) CNSE-5.0 (control diet and 5.0 g/d CNSE granule [containing 50% CNSE]; n = 34). Following parturition, 17 cows (preselected at initial treatment assignment) from the CNSE-5.0 treatment were reallocated into a third treatment group: CNSE-2.5 (control diet and 2.5 g/d CNSE granule; n = 17), resulting in 3 total treatments postpartum: (1) CON, (2) CNSE-2.5, and (3) CNSE-5.0. Prepartum rumen pH was unaltered by treatment; however, postpartum rumen pH was increased (0.31 units) in CNSE cows relative to CON. Prepartum rumen ammonia N concentration tended to be decreased (34%) in CNSE-5.0 cows compared with CON, and there tended to be a quadratic effect on postpartum ammonia N, as it was decreased in CNSE-2.5 compared with CON and CNSE-5.0. Prepartum dry matter intake (DMI) was unaffected by treatment; however, postpartum DMI was increased (8%) in CNSE cows relative to CON. No treatment differences were observed in pre- or postpartum digestibility measurements. Milk and protein yields from cows fed CNSE tended to be increased (6% and 7%, respectively) relative to CON. No treatment differences were detected for energy-corrected milk, feed efficiency, body weight, body condition score, energy balance, milk composition, milk urea nitrogen, or somatic cell count. Prepartum fecal pH decreased (0.12 units) in CNSE-5.0 cows relative to CON cows but was similar between treatments postpartum. Supplementing CNSE did not affect prepartum glucose, nonesterified fatty acids (NEFA), ß-hydroxybutyrate (BHB), or insulin. However, prepartum circulating blood urea nitrogen tended to be decreased and glucagon was decreased in CNSE-5.0 cows compared with CON (9 and 20%, respectively). Additionally, CNSE supplementation decreased glucose and insulin concentrations postpartum relative to CON cows (6% and 20%, respectively). Quadratic effects were detected for postpartum circulating NEFA and BHB such that their levels were increased in CNSE-2.5 cows relative to CON and CNSE-5.0. Pre- and postpartum circulating serum amyloid A, lipopolysaccharide-binding protein, and haptoglobin were unaffected by treatment. Overall, CNSE influenced some key rumen fermentation variables, altered postabsorptive metabolism, and increased production parameters in transition dairy cows.

Effects of dietary antioxidant supplementation on metabolism and inflammatory biomarkers in heat-stressed dairy cows.

Heat-stress-induced inflammation may be ameliorated by antioxidant supplementation due to the purported effects of increased production of reactive oxygen species or oxidative stress on the gastrointestinal tract barrier. Thus, study objectives were to evaluate whether antioxidant supplementation [AGRADO Plus 2.0 (AP); EW Nutrition] affects metabolism and inflammatory biomarkers in heat-stressed lactating dairy cows. Thirty-two mid-lactation multiparous Holstein cows were assigned to 1 of 4 dietary-environmental treatments: (1) thermoneutral (TN) conditions and fed a control diet (TN-CON; n = 8), (2) TN and fed a diet with AP (10 g antioxidant; n = 8), (3) heat stress (HS) and fed a control diet (HS-CON; n = 8), or (4) HS and fed a diet with AP (HS-AP; n = 8). The trial consisted of a 23-d prefeeding phase and 2 experimental periods (P). Respective dietary treatments were top-dressed starting on d 1 of the prefeeding period and continued daily throughout the duration of the experiment. During P1 (4 d), baseline data were collected. During P2 (7 d), HS was artificially induced using an electric heat blanket (Thermotex Therapy Systems Ltd.). During P2, the effects of treatment, day, and treatment-by-day interaction were assessed using PROC MIXED of SAS (SAS Institute Inc.). Heat stress (treatments 3 and 4) increased rectal, vaginal, and skin temperatures (1.2°C, 1.1°C, and 2.0°C, respectively) and respiration rate (33 breaths per minute) relative to TN cows. As expected, HS decreased dry matter intake, milk yield, and energy-corrected milk yield (32%, 28%, and 28% from d 4 to 7, respectively) relative to TN. There were no effects of AP on body temperature indices or production. Milk fat, protein, and lactose concentrations remained unaltered by HS or AP; however, milk urea nitrogen was increased during HS regardless of AP supplementation (26% relative to TN). Circulating glucose remained unchanged by HS, AP, or time. Additionally, HS decreased circulating glucagon (29% from d 3 to 7 relative to TN), but there was no additional effect of AP. There was a tendency for nonesterified fatty acid concentrations to be increased in HS-AP cows throughout P2 (60% relative to TN-CON), whereas it remained similar in all other treatments. Blood urea nitrogen increased for both HS treatments from d 1 to 3 before steadily decreasing from d 5 to 7, with the overall increase being most pronounced in HS-CON cows (27% relative to TN-CON). Further, supplementing AP decreased blood urea nitrogen in HS-AP on d 3 relative to HS-CON (15%). Circulating serum amyloid A tended to be and lipopolysaccharide binding protein was increased by HS, but neither acute-phase protein was affected by AP. Overall, AP supplementation appeared to marginally alter metabolism but did not meaningfully alter inflammation during HS.

Evaluating effects of zinc hydroxychloride on biomarkers of inflammation and intestinal integrity during feed restriction.

Objectives were to evaluate effects of supplemental zinc hydroxychloride (HYD; Micronutrients, Indianapolis, IN) on gut permeability, metabolism, and inflammation during feed restriction (FR). Holstein cows (n = 24; 159 ± 8 d in milk; parity 3 ± 0.2) were enrolled in a 2 × 2 factorial design and randomly assigned to 1 of 4 treatments: (1) ad libitum fed (AL) and control diet (ALCON; 75 mg/kg Zn from zinc sulfate; n = 6); (2) ad libitum fed and HYD diet (ALHYD; 75 mg/kg Zn from HYD; n = 6); (3) 40% of ad libitum feed intake and control diet (FRCON; n = 6); or (4) 40% of ad libitum feed intake and HYD diet (FRHYD; n = 6). Prior to study initiation, cows were fed their respective diets for 21 d. The trial consisted of 2 experimental periods (P) during which cows continued to receive their respective dietary treatments. Period 1 (5 d) served as the baseline for P2 (5 d), during which cows were fed ad libitum or restricted to 40% of P1 feed intake. In vivo total-tract permeability was evaluated on d 4 of P1 and on d 2 and 5 of P2, using the paracellular permeability marker chromium (Cr)-EDTA. All cows were euthanized at the end of P2 to assess intestinal architecture. As anticipated, FR cows lost body weight (∼46 kg), entered into calculated negative energy balance (-13.86 Mcal/d), and had decreased milk yield. Circulating glucose, insulin, and glucagon decreased, and nonesterified fatty acids and ß-hydroxybutyrate increased in FR relative to AL cows. Relative to AL cows, FR increased lipopolysaccharide-binding protein, serum amyloid A (SAA), and haptoglobin (Hp) concentrations (2-, 4-, and 17-fold, respectively); and peak SAA and Hp concentrations were observed on d 5. Circulating SAA and Hp from FRHYD tended to be decreased (47 and 61%, respectively) on d 5 relative to FRCON. Plasma Cr area under the curve increased (32%) in FR treatments on d 2 and tended to be increased (17%) on d 5 of P2 relative to AL treatments. No effects of diet were observed on Cr appearance. Relative to AL cows, FR increased jejunum villus width and decreased jejunum crypt depth and ileum villus height and crypt depth. Relative to FRCON, ileum villus height tended to increase in FRHYD cows. Feed restriction tended to decrease jejunum and ileum mucosal surface area, but the decrease in the ileum was ameliorated by dietary HYD. In summary, FR induced gut hyperpermeability to Cr-EDTA, and feeding HYD appeared to benefit some key metrics of barrier integrity.

Effects of a Saccharomyces cerevisiae fermentation product on heat-stressed dairy cows.

The objective of this study was to evaluate the effects of supplementing a Saccharomyces cerevisiae fermentation product (SCFP) on body temperature indices, metabolism, acute phase protein response, and production variables during heat stress (HS). Twenty multiparous lactating Holstein cows (body weight = 675 ± 12 kg; days in milk = 144 ± 5; and parity = 2.3 ± 0.1) were used in an experiment conducted in 2 replicates (10 cows/replicate). Cows were randomly assigned to 1 of 2 dietary treatments: control diet (CON; n = 10) or the CON diet supplemented with 19 g/d of SCFP (n = 10; NutriTek, Diamond V, Cedar Rapids, IA). Cows were fed their respective diets for 21 d before initiation of the study. The experiment consisted of 2 periods: thermoneutral (period 1; P1) and heat stress (period 2; P2). During P1 (4 d), cows were fed ad libitum and housed in thermoneutral conditions for collecting baseline data. During P2 (7 d), HS was artificially induced using an electric heat blanket (EHB; Thermotex Therapy Systems Ltd., Calgary, AB, Canada). Cows were fitted with the EHB for the entirety of P2. Rectal temperature, respiration rate, and skin temperature were obtained twice daily (0600 and 1800 h) during both periods. Overall, HS increased rectal temperature, skin temperature, and respiration rate (1.4°C, 4.8°C, and 54 breaths/min, respectively) relative to P1, but no dietary treatment differences were detected. Compared with P1, HS decreased dry matter intake and milk yield (36 and 26%, respectively), and the reductions were similar between dietary treatments. Relative to P1, HS increased milk fat content and milk urea nitrogen (17 and 30%, respectively) and decreased milk protein and lactose contents (7 and 1.4%, respectively). Overall, HS increased (52%) plasma cortisol concentrations of CON, but circulating cortisol did not change in SCFP-fed cows. Heat stress increased circulating lipopolysaccharide binding protein and serum amyloid A (SAA; 2- and 4-fold, respectively), and SCFP supplementation tended to decrease peak SAA (∼33%) relative to CON cows. Overall, although HS did not influence circulating white blood cells and neutrophils, SCFP increased circulating white blood cells and neutrophils by 9 and 26%, respectively, over CON in P2. In conclusion, HS initiated an acute phase protein response and feeding SCFP blunted the cortisol and SAA concentrations and altered some key leukocyte dynamics during HS.

Energetic metabolism, milk production, and inflammatory response of transition dairy cows fed rumen-protected glucose.

Objectives were to evaluate the effects of rumen-protected glucose (RPG) supplementation on milk production, post-absorptive metabolism, and inflammatory biomarkers in transition dairy cows. Fifty-two multiparous cows were blocked by previous 305-d mature-equivalent milk (305ME) yield and randomly assigned to 1 of 2 iso-energetic and iso-nitrogenous treatments: (1) control diet (CON; n = 26) or (2) a diet containing RPG (pre-fresh 5.3% of dry matter and 6.0% of dry matter postpartum; n = 26). Cows received their respective dietary treatments from d -21 to 28 relative to calving, and dry matter intake was calculated daily during the same period. Weekly body weight, milk composition, and fecal pH were recorded until 28 d in milk (DIM), and milk yield was recorded through 105 DIM. Blood samples were collected on d -7, 3, 7, 14, and 28 relative to calving. Data were analyzed using repeated measures in the MIXED procedure (SAS Institute Inc., Cary, NC) with previous 305ME as a covariate. Fecal pH was similar between treatments and decreased (0.6 units) postpartum. Dry matter intake pre- and postpartum were unaffected by treatment, as was milk yield during the first 28 or 105 DIM. Milk fat, protein, and lactose concentration were similar for both treatments. Blood urea nitrogen and plasma glucose concentrations were unaffected by treatment; however, results showed increased concentration of circulating insulin (27%), lower nonesterified fatty acids (28%), and lower postpartum ß-hydroxybutyrate (24%) in RPG-fed cows. Overall, circulating lipopolysaccharide-binding protein and haptoglobin did not differ by treatment, but at 7 DIM, RPG-fed cows had decreased lipopolysaccharide-binding protein and haptoglobin concentrations (31 and 27%, respectively) compared with controls. Supplemental RPG improved some biomarkers of post-absorptive energetics and inflammation during the periparturient period, changes primarily characterized by increased insulin and decreased nonesterified fatty acids concentrations, with a concomitant reduction in acute phase proteins without changing milk production and composition.

Effects of dietary zinc source on the metabolic and immunological response to lipopolysaccharide in lactating Holstein dairy cows.

The objectives of this study were to evaluate the effects of replacing 40 mg/kg of Zn from Zn sulfate (control; CON) with Zn AA complex (AvZn) on metabolism and immunological responses following an intravenous lipopolysaccharide (LPS) challenge in lactating cows. Cows were randomly assigned to 1 of 4 treatments: (1) pair-fed (PF) control (PF-CON; 5 mL of saline; n = 5), (2) PF AvZn (PF-AvZn; 5 mL of saline; n = 5), (3) LPS euglycemic clamp control (LPS-CON; 0.375 µg of LPS/kg of BW; n = 5), and (4) LPS euglycemic clamp AvZn (LPS-AvZn; 0.375 µg of LPS/kg of BW; n = 5). Cows were enrolled in 3 experimental periods (P). During period 1 (3 d), cows received their respective dietary treatments and baseline data were obtained. During period 2 (P2; 2 d), a 12-h LPS euglycemic clamp was conducted or cows were PF to their respective dietary counterparts. During period 3 (P3; 3 d), cows received their dietary treatment and consumed feed ad libitum. Mild hyperthermia (1°C) was observed in LPS cows at 3 h postbolus. Throughout P2, the rectal temperature of LPS-AvZn cows was decreased (0.3°C) relative to LPS-CON cows. Administrating LPS decreased dry matter intake (47%) during P2, and by experimental design the pattern was similar in PF cohorts. During P3, dry matter intake from LPS cows remained decreased (15%) relative to PF cows. Milk yield from LPS cows decreased (54%) during P2 relative to PF cows, but it was similar during P3. During P2, somatic cell count increased 3-fold in LPS cows relative to PF controls. Dietary AvZn tended to decrease somatic cell count (70%) during P3 relative to LPS-CON cows. Insulin increased 7-fold in LPS cows at 12 h postbolus and remained increased (4-fold) for the duration of P2. Circulating glucagon from LPS cows increased (65%) during P2, and supplementing AvZn blunted the increase (30% relative to LPS-CON). During P2, circulating cortisol increased 7-fold post-LPS infusion relative to PF cows, and supplementing AvZn decreased cortisol (58%) from 6 to 48 h postbolus relative to LPS-CON cows. Administrating LPS increased circulating LPS-binding protein and serum amyloid A (3- and 9-fold, respectively) relative to PF cows. Compared with LPS-CON, LPS-AvZn cows had increased circulating serum amyloid A (38%) 24 h postbolus. The 12-h total glucose deficit was 36 and 1,606 g for the PF and LPS treatments, respectively, but was not influenced by Zn source. In summary, replacing a portion of the Zn sulfate with Zn AA complex appeared to reduce the inflammatory response but had no effect on the glucose deficit.