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. 2018 Jun 23;96(9):3955–3966. doi: 10.1093/jas/sky255

Effect of a hydrolyzed mannan- and glucan-rich yeast fraction on performance and health status of newly received feedlot cattle1

Josey R Pukrop 1, Kristen M Brennan 2, Bethany J Funnell 3, Jon P Schoonmaker 1,✉
PMCID: PMC6127785  PMID: 29939269

Abstract

A 2-part experiment was conducted to determine the effects of a blend of specialized mannan- and glucan-rich fractions of yeast (Select-TC, Alltech Inc.) on the health status and performance of steers during the first 2 mo of the feedlot period. Eighty crossbred steers were acquired from commercial sale barns in Mississippi and Georgia and transported to Purdue University. All animals were fed a corn silage-based receiving diet and were checked and treated daily for respiratory disease as needed following established treatment protocols. In Exp. 1, 64 steers (246.5 ± 4.7 kg initial weight) were blocked by BW and randomly allocated to 2 treatments to determine the impact of supplementation of a hydrolyzed mannan- and glucan-rich yeast fraction for 56 d on BW, ADG, daily DMI, and G:F: hydrolyzed yeast fed at 13 g (as-fed)/steer daily (TC) or nonsupplemented control (CON). Steers in Exp. 1 were housed in bedded pens with 2 animals per pen [n = 16 pens (32 steers)/treatment]. In Exp. 2, 16 steers (247.1 ± 5.4 kg initial BW) were similarly allotted to 2 treatments (CON and TC), individually penned, and subjected to a lipopolysaccharide (LPS) endotoxin challenge on day 62 or 63 after the start of the study to determine the animal’s response to an inflammatory agent. Serum samples and rectal temperatures were taken every half an hour from −2 to 8 h relative to LPS injection from steers in Exp. 2. Data were analyzed as a complete randomized block design using the MIXED procedure of SAS. Morbidity for both experiments did not differ (P ≥ 0.16). Weight, ADG, DMI, and G:F did not differ among treatments (P ≥ 0.32) in Exp. 1. After the LPS infusion in Exp. 2, rectal temperatures (P = 0.03) and serum NEFA concentration (P = 0.04) were decreased in TC compared with CON steers. Concentrations of blood urea nitrogen (P = 0.31), glucose (P = 0.70), insulin (P = 0.57), and cortisol (P = 0.77) did not differ by treatment after LPS administration. Serum IL-6 concentrations were decreased (P < 0.0001), and interferon-γ concentrations tended to be greater (P = 0.07) in TC compared with CON steers after LPS infusion. Serum cytokine and metabolite results indicate that Select-TC improved health and metabolic status of LPS-challenged cattle, but this did not result in quantifiable improvements in performance in the conditions observed in this study.

Keywords: feedlot, health, inflammatory response, lipopolysaccharide, receiving period, yeast cell wall

INTRODUCTION

The time period associated with a calf entering the feedlot is considered one of the most stressful events in the beef cattle lifecycle (Duff and Galyean, 2007). During this time, a calf is commingled, subjected to a new host of pathogens, transported, and introduced to a new diet and environment, and potentially weaned, dehorned, castrated, and vaccinated. These stressors contribute to decreased gastrointestinal tract (GIT) barrier function, which results in an increased susceptibility to pathogens (Zhang et al., 2013). Therefore, the major goal of the receiving period is to get calves to eat a maximum amount of feed, thus providing nutrients to fight disease and to overcome immune challenges from stress.

Yeast cell walls (YCW) are often fed to cattle as a prebiotic during periods of stress to improve health and performance. Mannan and glucan are complex polysaccharides that are derived from YCW that can bind toxins as well as block colonization of pathogens in the digestive tract (Spring et al., 2015). These YCW polysaccharides can also interact directly with immune cells to improve gastrointestinal health (Broadway et al., 2015). Esterified glucomannan from the YCW has been shown to bind aflatoxin in dairy cows (Diaz et al., 2004), thereby reducing toxic effects. Removing pathogens and toxins allows the remaining bacterial population to flourish and helps the GIT to be more efficient at nutrient digestion and absorption, allowing a greater amount of nutrients to be available for utilization by the animal (Spring et al., 2015). In general, YCW are thought to have greater efficacy than live yeast due to the concentration of cellular components (Burdick Sanchez et al., 2014).

Previous reports have demonstrated that cattle receiving YCW have improved intake and have the potential to better respond to illness when challenged with a bacterial endotoxin (Burdick Sanchez et al., 2013, 2014; Finck et al., 2014). Keyser et al. (2007) observed a decrease in morbidity rate, a decrease in recovery time from bovine respiratory disease infection, and a decrease in the negative effects of antibiotic treatment on feed intake in heifers fed Saccharomyces cerevisiae boulardii. Our hypothesis was that supplementing a proprietary blend of specialized mannan- and glucan-rich fractions of yeast (Select-TC, Alltech Inc., Nicholasville, KY) will improve health, DMI, and daily gain of receiving cattle and will decrease inflammation during a bacterial endotoxin challenge. The objectives of this study were to examine the effect of supplementing a hydrolyzed mannan- and glucan-rich yeast fraction during the first 56 d in the feedlot on morbidity and performance of receiving cattle and to determine their immune response during a bacterial endotoxin challenge after 63 d of supplementation.

MATERIALS AND METHODS

This study was performed at the Purdue University Animal Sciences Research and Education Center (ASREC) in West Lafayette, IN. All procedures involving animal care and management were approved by the Purdue University Animal Care and Use Committee and were in accordance with the Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching (FASS, 2010).

Animals and Diets

Two experiments were conducted concurrently to determine the effect of a hydrolyzed mannan- and glucan-rich yeast fraction on performance (Exp. 1) and response to an immune challenge (Exp. 2). Steers in Exp. 1 were fed treatment diets for 56 d, and steers in Exp. 2 were fed treatment diets for 63 d. Eighty mixed breed steers (246.7 ± 4.9 kg initial BW) were sourced from commercial sale barns in Georgia and Mississippi and transported approximately 1,125 km to the Animal Science Research and Education Center (ASREC) Beef Unit at Purdue University. Due to the nature of the marketing channels and transportation, cattle were considered high stress. Within 24 h of arriving at ASREC (day 0), steers were weighed, ear tagged, vaccinated with a clostridial bacterin toxoid (Vision 7 with SPUR, Merck Animal Health, Whitehouse Station, NJ) and a modified live respiratory disease vaccine (INFORCE 3, Zoetis Animal Health, Florham Park, NJ), given an injectable mineral (Multimin 90, Multimin USA, Fort Collins, CO), and received an anthelmintic (Valbazen, Zoetis Animal Health, Kalamazoo, MI) and a permethrin pour-on (Ultra Boss, Intervet/Merck Animal Health, Summit, NJ). Steers were weighed on days 0 and 1, blocked by BW, and allotted to the 2 experiments and then to the same 2 treatments within each experiment. Scales (Tru-Test XR3000; Tru-Test Inc., Mineral Wells, TX) weighed to the nearest 0.9 kg (<453.6 kg) or 2.3 kg (>453.6 kg) and were checked for accuracy at each weigh date. Steers were placed in an open-sided barn in straw-bedded pens (2.4 × 9.1 m) over a concrete floor.

Treatments consisted of 1) control (CON; no additive) and 2) a hydrolyzed mannan- and glucan-rich yeast fraction (Select-TC, Alltech) fed at 13 g (as-fed)/steer daily (TC). Treatments were mixed in a ground corn-based top-dress and were delivered to bunks at a rate of 454 g/steer immediately after delivery of the basal ration beginning on day 1 of the study. The basal rations were formulated to meet or exceed NASEM (2016) requirements for protein, vitamins, and minerals. Diet I was fed from day 0 to 13 and consisted (DM basis) of 48.5% corn silage, 30% DDGS, 15% corn stover, 6% mineral, and 0.5% urea. Due to palatability issues, the corn stover in diet I was replaced with corn silage in diet II. Diet II was fed from day 14 to 56 (Exp. 1) or day 63 (Exp. 2) and contained (DM basis) 62.5% corn silage, 30% DDGS, 6% mineral, and 0.5% urea. Diet composition is presented in Table 1. The diet was fed once daily at 0900 h, and steers were allowed ad libitum access to feed and water. Daily feed deliveries were adjusted using a 4-point bunk scoring system (Pritchard, 1993) to allow for ad libitum feed intake with little or no accumulation of unconsumed feed. Feed delivery was recorded daily for each pen. Feed samples were collected every 2 wk for DM analysis (AOAC, 1990), composited equally by weight, and a subsample was analyzed by wet chemistry for CP, NDF, Ca, and P (Cumberland Valley Analytical Services, Waynesboro, PA).

Table 1.

Diet composition offered to steers during feedlot receiving (day 1 to 56 in Exp. 1; day 1 to 63 in Exp. 2)

Ingredients, % DM basis Diet I1 Diet II2
Corn silage, % 48.5 63.5
DDGS, % 30.0 30.0
Corn stover, % 15.0 0.0
Mineral premix, %3 6.0 6.0
Urea, % 0.5 0.5
Nutrient composition, DM basis
 DM, % 84.2 71.8
 CP, % 14.9 15.2
 NDF, % 44.2 38.9
 NEm, Mcal/kg 1.60 1.69
 NEg, Mcal/kg 1.02 1.10
 Ca, % 1.22 1.20
 P, % 0.47 0.48
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1Diet I was fed from day 1 to 13.

2Diet II was fed from day 14 to 56 (Exp.1) or day 63 (Exp. 2).

3Vitamin/mineral premix contained (DM basis): 18.25% Ca, 0.44% Mg, 1.32% K, 0.18% S, 3.43 ppm Co, 183.33 ppm Cu, 9.66 ppm I, 522.90 ppm Fe, 440.41 ppm Mn, 4.48 ppm Se, 563.91 ppm Zn, 42.19 IU/g vitamin A, 4.98 IU/g vitamin D, 0.155 IU/g vitamin E, 413.6 ppm Rumensin (176.4 g/kg; Elanco Animal Health, Indianapolis, IN).

In Exp. 1, 64 steers (246.5 ± 4.7 kg initial BW) were used to evaluate performance over a 56-d period (day 0 to 56). Pens (2.4 × 9.1 m) contained 2 steers each. Pens were randomly allotted to treatment with BW allocated evenly between treatments. Individual BW was collected biweekly. In Exp. 2, 16 steers (247.1 ± 5.4 kg initial BW) were randomly allotted to individual pens (2.4 × 9.1 m) to evaluate their response to a lipopolysaccharide (LPS) challenge after receiving experimental diets for 62 or 63 d; steers continued to receive their respective treatment through the conclusion of the LPS challenge. Steers in Exp. 2 were halter broken starting in week 3 and were periodically handled prior to the LPS challenge. Steers in both experiments were observed by Purdue University staff daily at feed delivery and subsequently evaluated by Purdue University veterinarians daily for signs of respiratory disease, including nasal or ocular discharge, lethargy, labored breathing, coughing, or dehydration to determine whether cattle should be pulled for potential treatment. Cattle that exhibited abnormal lung sounds or rectal temperature >39.7 °C were treated with an antimicrobial according to label instructions. Cattle were first treated with tilmicosin (Micotil, Elanco Animal Health, Greenfield, IN). Sensitivity testing using broth dilution and evaluation of minimum inhibitory concentration of antimicrobials was performed on tracheal samples that were collected via trans-tracheal washing the first day of treatment to determine whether antibiotic therapy was appropriate. Any cattle treated for a second time were treated with tulathromycin (Draxxin, Zoetis Animal Health, Parsippany-Troy Hills, NJ). Banamine (Merck Animal Health, Kenilworth, NJ) was administered in conjunction with the treatment when rectal temperature was ≥40 °C to decrease inflammation and body temperature. Each time a steer was treated for sickness, it was recorded as one treatment.

Lipopolysaccharide Challenge

On day 62 to 63, 8 steers/d were subjected to an LPS challenge, as described by Burdick et al. (2012) with modifications. Four CON and 4 TC steers were subjected to the LPS challenge each day. The challenge was chosen to be at the conclusion of the trial when cattle were not exhibiting clinical signs of disease to reduce potential confounding factors. Cattle were restrained in a working chute, and approximately 50 cm of sterile polyethylene tubing (Becton Dickinson and Co., Sparks, MD; 1.19 mm I.D., 1.70 mm O.D.) was inserted into the jugular vein using a 13 gauge by 8.9-cm stainless steel biomedical needle. A saline solution containing 2 USP/mL of heparin was injected into the catheter line to prevent blood clotting. The catheter line was fixed to the animal using surgical tape and super glue and secured with Vetrap (3M, St. Paul, MN). Steers were immediately moved to individual stalls (1.1 × 2.1 m), the Vetrap was removed, and the catheter line was attached to the stall using string. After catheterization, steers were allowed to rest in the stalls for at least 1 h prior to the first sample collection. Feed and water were offered ad libitum throughout the challenge period. Lipopolysaccharide (0.5 µg/kg of BW LPS; Escherichia coli O111:B4; Sigma–Aldrich, St. Louis, MO) was administered at hour 0, and blood samples and rectal temperatures were taken every 0.5 h from −2 to 8 h relative to LPS administration. Rectal temperature was recorded with a hand thermometer (8-s reading time; ReliOn, Bentonville, AR) immediately following blood collection at each sampling point. Prior to each blood sample, 12 mL of fluid was removed from the catheter line and discarded. Three aliquots (10 mL each) of blood were collected into serum tubes (BD Vacutainer; Becton Dickinson, Franklin Lakes, NJ) and allowed to clot for 30 to 45 min at room temperature. Following each sample, 5 mL of saline and 5 mL of heparinized saline were inserted into the catheter line to replace fluid volume and prevent clotting in the catheter line. Blood collection tubes were centrifuged at 1,250 × g for 20 min at 4 °C. Serum was recovered, transferred to 5-mL polystyrene tubes, and frozen at −20 °C until analysis. One steer from the CON treatment was removed at hour 1.5 due to catheter line failure.

Serum Analyses

All assays were performed in duplicate using serum, with a maximum intra-assay CV of 10%, and were performed according to the manufacturer’s instructions. Nonesterified fatty acid concentration was determined using an acyl-CoA synthetase/acyl-CoA oxidase enzyme kit (NEFA C Kit, Wako Diagnostics Inc., Richmond, VA), and absorbance was read at a wavelength of 550 nm with a Tecan Spark 10M multimode microplate reader (Tecan Trading AG, Mannedorf, Switzerland). Blood urea nitrogen (BUN) was determined using a diacetylmonoxime kit (Procedure 0580, Stanbio Laboratory, Boerne, TX), and absorbance was read at 530 nm using the previously described plate reader. Glucose concentrations were determined using a biochemistry analyzer (YSI 2900, Yellow Springs, OH). Insulin (EMD Millipore, Billerica, MA) and cortisol (ImmuChem Coated Tube, MP Biomedicals, LLC, Solon, OH) were analyzed using Iodine125 radioimmunoassay kits and a gamma counter (Cobra II Auto-Gamma; Packard Instrument Co., Downers Grove, IL). Concentrations of IL-6 and interferon-γ (IFN-γ) were determined using bovine specific ELISA reagent kits ESS0029 and ESS0026B, respectively (Thermo Scientific, Rockford, IL), and absorbance was read at a wavelength of 450 nm using the previously described plate reader.

Statistical Analysis

Data were analyzed using the MIXED procedure of SAS 9.4 (SAS Institute Inc., Cary, NC) with pen was the experimental unit in Exp. 1 and individual as the experimental unit in Exp. 2. Data in Exp. 1 were analyzed as a completely randomized design, and data in Exp. 2 were analyzed as a complete randomized block design with day of LPS challenge as a blocking factor. The Shapiro–Wilk test was performed to test for normality. Performance and LPS temperature and serum data were analyzed using repeated measures with treatment, time, and treatment × time interactions included in the model as fixed effects and autoregressive order one used as the covariance structure. Pen was included as a random variable for performance and morbidity data, whereas animal, technician, and day of LPS challenge were included as random variables for temperature and serum analyses. Pre-LPS data were used as a covariate for post-LPS analyses. Treatment comparisons were made using Fisher’s protected least significant difference, and the least square means statement was used to calculate adjusted means. The SLICE function of SAS was used to determine simple effects within time. Morbidity was analyzed as binary data using the GLIMMIX procedures of SAS. Differences were considered significant when P ≤ 0.05, and 0.05 < P ≤ 0.10 was considered a tendency.

RESULTS AND DISCUSSION

Performance

Performance results are presented in Table 2. Weight increased from day 0 to 56, ADG and DMI increased from period 1 to 2, and G:F decreased from period 1 to 2 (time effect; P < 0.0001). There were no differences in BW, ADG, DMI, or G:F (P ≥ 0.32) between treatments throughout the duration of the study. Supplementation of yeast and YCW has had variable impacts in previous reports. Finck et al. (2014) observed that supplementing receiving steers with a live yeast, YCW or a combination of live yeast and YCW did not affect BW, ADG, or G:F for the duration of a 56-d study, but all yeast supplemented groups had greater DMI compared with control steers. Burdick Sanchez et al. (2014) supplemented receiving heifers with one of 2 types of YCW and observed no differences in BW or ADG among treatments for the 52-d study. Source of YCW, as well as the condition of calves when they received YCW, seems to have an influence on the effectiveness of the YCW. It has been reported that beneficial effects of yeast supplementation are more pronounced under stressed vs. normal conditions (Cole et al., 1992). Young et al. (2017) tested 3 different YCW derived from S. cerevisiae in feedlot heifers sourced from 2 sale barns in Texas and observed that heifers from just one of the sale barns responded only to one of the strains of YCW. In this case, heifers appeared to be in poorer condition on arrival, and ADG, BW, and DMI were increased for the first 42 d, final BW at 56 d was improved, and ADG, DMI, and G:F after an LPS challenge were improved (Young et al., 2017). Martin et al. (2010) reported that DMI in veal calves increased when YCW was included in a diet that was contaminated with mycotoxins, but DMI was decreased when YCW was introduced into a diet with no mycotoxin contamination (Martin et al., 2010). Sánchez-Mendoza et al. (2015) observed that a chromium-enriched YCW increased ADG and tended to increase DMI during the first 112 d of a trial, but not the last 100 d or overall compared with no YCW. Holstein steers supplemented with 0, 195, 390, or 585 mg/kg diet DM of enzymatically hydrolyzed YCW + yeast culture for 336 d had increased overall DMI, ADG, and final carcass weight, with maximal effects observed at 195 mg/kg YCW (Salinas-Chavira et al., 2017). The inclusion of YCW for the final 55 d in steers fed zilpaterol hydrochloride resulted in increased carcass adjusted final BW, ADG, and G:F from day 21 to 55, but there were no other differences in performance or carcass characteristics (Aragon et al., 2016). Performance of steers supplemented with 0, 1, 2, or 3 g/d of an enzymatically hydrolyzed YCW for 229 d did not differ over the first 139 d of the trial, but inclusion of YCW linearly increased DMI and ADG when the 24-h temperature humidity index averaged 80 from d 139 to harvest (Salinas-Chavira et al., 2015), suggesting that YCW may be of greater benefit in cases of high heat. It may be possible in the present study that cattle were not stressed enough to exhibit a performance response to supplemental hydrolyzed mannan- and glucan-rich yeast fraction.

Table 2.

Effect of a hydrolyzed mannan- and glucan-rich yeast fraction on growth performance in a 56-d receiving period in feedlot steers in Exp. 1

Treatment1 P-value
Item CON TC SE
BW, kg
 Day 0 246.2 246.8 4.74 0.93
 Day 28 268.5 271.4 4.74 0.67
 Day 56 301.7 301.7 4.74 0.99
ADG, kg/d
 Day 0 to 28 0.79 0.88 0.073 0.43
 Day 29 to 56 1.19 1.08 0.073 0.32
 Day 0 to 56 0.99 0.98 0.073 0.91
DMI, kg
 Day 0 to 28 3.4 3.5 0.21 0.70
 Day 29 to 56 5.9 5.9 0.21 0.93
 Day 0 to 56 4.6 4.6 0.21 0.86
G:F
 Day 0 to 28 0.227 0.246 0.0175 0.45
 Day 29 to 56 0.199 0.184 0.0112 0.35
 Day 0 to 56 0.216 0.209 0.0063 0.49
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1CON = control (no feed additives); TC = 13 g/steer daily of a hydrolyzed mannan- and glucan-rich yeast fraction (Select-TC, Alltech Inc., Nicholasville, KY).

The mechanism for enhanced performance to YCW supplementation still has not been fully elucidated (Finck et al., 2014; Broadway et al., 2015). Calves have natural resistance to infectious diseases, but require a sufficient nutritional supply to maintain health. It is possible that YCW influences appetite by decreasing GIT inflammation caused by LPS endotoxins of gram-negative bacteria naturally present in an acidic ruminal environment after transition to concentrate rich diets (Plaizier et al., 2012). Lei et al. (2013) demonstrated that feeding 2 g/kg of YCW decreased the LPS concentration in blood, ileum, cecum, colon, and fecal samples and elicited a smaller acute-phase response in receiving steers. In addition, apparent digestibility of ADF and total phosphorus were increased, and ADG and G:F were improved (Lei et al., 2013). The stress of transportation and a new environment during the transition to the feedlot often cause depressed intake, decreasing the supply of nutrients to the body at a time when the calf has high nutrient demands. This depressed intake magnifies any negative effects of the receiving period on performance and immune function (Bernhard et al., 2012). Therefore, animals that consume more feed should be capable of supplying additional energy to immune defenses and remain healthier.

Morbidity

Yeast and YCW may improve DMI in cattle as a result of improved health. The mannan and β-glucan components in YCW act as immunomodulators that can modify biological responses, helping to alleviate the negative effects of pathogenesis and morbidity (Broadway et al., 2015). Morbidity results for the present study are presented in Table 3. The total morbidity rate was low in the current study (21.4%). Although total morbidity was 14.9% in TC steers vs. 27.8% in CON steers, there was no difference in morbidity between treatments (P = 0.19). Of the steers treated, 5.0% of CON steers required more than one treatment, and no TC steers required multiple treatments (P = 0.97). The incidences of morbidity requiring treatment for both CON and TC occurred between day 5 and day 21 of the study. Buntyn et al. (2016b) similarly observed low morbidity rates, and although there was a trend for steers fed 30% dry-rolled corn diets supplemented with an active dried yeast for either 28 d or the entire feeding period to have a decreased morbidity rate, it did not differ from control animals. Finck et al. (2014) observed a total morbidity rate of 42.6% and observed no effect among highly stressed cattle fed an 88% concentrate diet supplemented with no yeast, a live yeast, YCW, or a combination of live yeast and YCW. Keyser et al. (2007) observed that live yeast did not affect morbidity in newly received beef heifers fed 65% concentrate diets, with morbidity rates of 33.1% and 40.2% for yeast and no yeast treatments, respectively. In contrast, newly received steers supplemented with 0.5, 1.0, 3.0, or 5.0 g/d of an active dry yeast for 32 d had a linear increase in morbidity rates compared with steers not receiving yeast (Buntyn et al., 2016a). Diets containing increased proportions of concentrate seem to lead to a greater incidence and severity of respiratory disease (Galyean et al., 1999). It may be possible that the low morbidity rates seen in the present study were the result of the moderate concentrate amount or were a result of low commingling stress.

Table 3.

Effect of a hydrolyzed mannan- and glucan-rich yeast fraction on respiratory treatment rates in feedlot steers fed a receiving diet for 56 d (Exp. 1) or 63 d (Exp. 2)

Item Treatment1 SE P-value
CON TC
Treated once, % 23 15 6.4 0.40
Treated twice, % 5 0 2.5 0.97
Total morbidity events, % 28 15 6.9 0.19
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1CON = control (no feed additives); TC = 13 g/steer daily of a hydrolyzed mannan- and glucan-rich yeast fraction (Select-TC, Alltech Inc., Nicholasville, KY).

Rectal Temperature during LPS Challenge

Fever occurs as an element of the acute-phase response to infection and has been associated with shortened disease duration (Hasday et al., 2000). In cattle, prolonged, low-dose LPS administration results in an overall increase in rectal temperature (Steiger et al., 1999). Increases in rectal temperature serve as an immediate indicator of potential disease or illness (Duff and Galyean, 2007). In the present study, there was a 0.7 to 1.2 °C increase in rectal temperature (Fig. 1) after the LPS was administered as the body recognized and reacted to an endotoxin. Rectal temperature did not differ between treatments prior to LPS administration (P = 0.28); however, after LPS administration, rectal temperature for TC steers did not increase as much as control steers and was lesser throughout the LPS challenge (treatment effect, P = 0.03). The lessened temperature response for TC steers is similar to other studies in which cattle were supplemented with YCW (Burdick Sanchez et al., 2013; Finck et al., 2014). The muted increase in rectal temperature in TC compared with CON steers signifies a decrease in inflammation and heat production in response to a pathogen, suggesting that steers supplemented with YCW were immunologically more competent to handle a disease challenge.

Figure 1.

Figure 1.

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Rectal temperature in response to a lipopolysaccharide challenge (LPS; 0.5 µg/kg BW) at time 0 h in receiving steers fed diets for 63 d. CON = control, no yeast cell wall feed additive (n = 8). TC = a hydrolyzed mannan- and glucan-rich yeast fraction (Select-TC, Alltech Inc., Nicholasville, KY) fed at 13 g/steer daily (n = 8). Data are presented as least square means ± SEM. Pre-LPS treatment P = 0.28; pre-LPS treatment × time P = 0.57; post-LPS treatment P = 0.03; post-LPS treatment × time P = 0.82.

Metabolites and Hormones during LPS Challenge

During an immunologic stress, energy is shifted to a catabolic state where lipids and proteins are broken down to provide energy for defenses, with adipose tissue generally serving as the primary source for energy (Elsasser et al., 2008). There is evidence in swine suggesting that skeletal muscle protein degradation occurs as either a direct or indirect result of cytokine synthesis during a LPS challenge (Johnson, 1997). Adipose tissue catabolism can be estimated by analyzing serum for NEFA concentration, whereas amino acid catabolism can be estimated by analyzing serum for BUN concentrations (Ellenberger et al., 1989). An increase in either NEFA or BUN concentrations is unfavorable, as it represents an increase in lipid or protein breakdown. Administration of a hydrolyzed mannan- and glucan-rich yeast fraction in the current study did not affect NEFA concentrations (Fig. 2) prior to the LPS challenge (P = 0.42), but the increase in serum NEFA after LPS administration was diminished in cattle fed TC compared with CON (P = 0.04). Serum BUN concentrations (Fig. 3) did not differ prior to (P = 0.32) or after LPS infusion (P = 0.31). Burdick Sanchez et al. (2014) observed that one YCW product did not affect serum NEFA but increased serum BUN concentrations, whereas a second YCW product decreased serum NEFA and had no effect on serum BUN concentrations relative to steers not fed YCW. Buntyn et al. (2016b) observed that supplementation of an active dried yeast decreased both serum NEFA and BUN concentrations in steers during an LPS challenge compared with CON steers, suggesting that supplemented steers required less energy to mount an immune response.

Figure 2.

Figure 2.

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Serum concentrations of nonesterified fatty acids in response to a lipopolysaccharide challenge (LPS; 0.5 µg/kg BW) at time 0 h in receiving steers fed diets for 63 d. CON = control, no yeast cell wall feed additive (n = 8). TC = a hydrolyzed mannan- and glucan-rich yeast fraction (Select-TC, Alltech Inc., Nicholasville, KY) fed at 13 g/steer daily (n = 8). Data are presented as least square means ± SEM. Pre-LPS treatment P = 0.42; pre-LPS treatment × time P = 0.57; post-LPS treatment P = 0.04; post-LPS treatment × time P = 0.26.

Figure 3.

Figure 3.

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Serum concentrations of blood urea nitrogen in response to a lipopolysaccharide challenge (LPS; 0.5 µg/kg BW) at time 0 h in receiving steers fed diets for 63 d. CON = control, no yeast cell wall feed additive (n = 8). TC = a hydrolyzed mannan- and glucan-rich yeast fraction (Select-TC, Alltech Inc., Nicholasville, KY) fed at 13 g/steer daily (n = 8). Data are presented as least square means ± SEM. Pre-LPS treatment P = 0.32; pre-LPS treatment × time P = 0.29; post-LPS treatment P = 0.31; post-LPS treatment × time P = 0.51.

Glucose is an important energy source for the body during the immune response and has been cited as the most important fuel for lymphocytes (Calder et al., 2007). Through glucose metabolism, substantial quantities of NADPH can be generated for immune cell function (Calder et al., 2007). When subjected to an endotoxin challenge, the animal often enters a hyperglycemic state in which more glucose is produced than utilized (Lang et al., 1985; Steiger et al., 1999). A state of hyperglycemia may have proinflammatory effects, and insulin may have anti-inflammatory and immune promoting effects (Calder et al., 2007). In addition, insulin has been reported to modulate the immune response both directly and indirectly through signal transduction and proliferative responses on immune cells (Helderman, 1981). As the immune response progresses and more glucose is utilized for immune cell function than what is available, the animal will switch to a hypoglycemic state. The amount of time it takes for the animal to become hypoglycemic is dependent on hepatic glycogen stores (Lang et al., 1985). During this hypoglycemic state, lipolysis is enhanced (Steiger et al., 1999). Serum glucose concentrations in the present study followed this hyperglycemic and hypoglycemic state (Fig. 4), but did not differ between treatment either before (P = 0.33) or after (P = 0.70) the LPS infusion. There tended to be a treatment × time interaction for glucose prior to the LPS infusion (P = 0.07), where TC steers had numerically greater serum glucose between −2 and −1.5 h but numerically less serum glucose compared with CON steers between −1 and 0 h. There was no treatment × time interaction for serum glucose after the LPS infusion (P = 0.16). The glucose results are consistent with the insulin results (Fig. 5). Concentrations of serum insulin did not differ by treatment either before (P = 0.61) or after (P = 0.57) the LPS infusion. Insulin concentration peaked at 2.5 h and returned to baseline concentrations by 5-h post-LPS. In contrast to the present study, Burdick Sanchez et al. (2014) reported that 2 different YCW products increased serum insulin concentrations and one of them decreased serum glucose concentrations after an LPS infusion. Buntyn et al. (2016b) reported increased concentrations of glucose both before and after an LPS infusion in steers supplemented with an active dried yeast compared with steers not supplemented with yeast. Our results suggest that a hydrolyzed mannan- and glucan-rich yeast fraction did not impact how glucose was utilized during an immune challenge despite changes in NEFA concentrations.

Figure 4.

Figure 4.

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Serum concentrations of glucose in response to a lipopolysaccharide challenge (LPS; 0.5 µg/kg BW) at time 0 h in receiving steers fed diets for 63 d. CON = control, no yeast cell wall feed additive (n = 8). TC = a hydrolyzed mannan- and glucan-rich yeast fraction (Select-TC, Alltech Inc., Nicholasville, KY) fed at 13 g/steer daily (n = 8). Data are presented as least square means ± SEM. Pre-LPS treatment P = 0.33; pre-LPS treatment × time P = 0.07; post-LPS treatment P = 0.70; post-LPS treatment × time P = 0.16.

Figure 5.

Figure 5.

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Serum concentrations of insulin in response to a lipopolysaccharide challenge (LPS; 0.5 µg/kg BW) at time 0 h in receiving steers fed diets for 63 d. CON = control, no yeast cell wall feed additive (n = 8). TC = a hydrolyzed mannan- and glucan-rich yeast fraction (Select-TC, Alltech Inc., Nicholasville, KY) fed at 13 g/steer daily (n = 8). Data are presented as least square means ± SEM. Pre-LPS treatment P = 0.61; pre-LPS treatment × time P = 0.67; post-LPS treatment P = 0.57; post-LPS treatment × time P = 0.99.

Cortisol prevents hyperinflammation caused by overproduction of proinflammatory cytokines (Roth and Kaeberle, 1982) and is partially responsible for alterations in the metabolism of carbohydrates, protein, and lipids in mammals (Renaville et al., 2002). In the current study, serum cortisol concentrations began increasing immediately following LPS administration at 0 h and did not return to baseline concentrations until 8-h post-LPS administration (Fig. 6). There were no differences in serum cortisol concentrations prior to (P = 0.79) or after the LPS infusion (P = 0.77) due to treatment. This is in contrast with other studies where yeast and/or YCW was observed to decrease serum cortisol concentrations after an LPS infusion (Burdick Sanchez et al., 2013; Buntyn et al., 2016a,b). Differences in cortisol response to LPS infusion among individuals may be due to differences in sex, breed, or existing immune status or stressors prior pathogen exposure (Arthington et al., 2003; Burdick Sanchez et al., 2013).

Figure 6.

Figure 6.

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Serum concentrations of cortisol in response to a lipopolysaccharide challenge (LPS; 0.5 µg/kg BW) at time 0 h in receiving steers fed diets for 63 d. CON = control, no yeast cell wall feed additive (n = 8). TC = a hydrolyzed mannan- and glucan-rich yeast fraction (Select-TC, Alltech Inc., Nicholasville, KY) fed at 13 g/steer daily (n = 8). Data are presented as least square means ± SEM. Pre-LPS treatment P = 0.79; pre-LPS treatment × time P = 0.99; post-LPS treatment P = 0.77; post-LPS treatment × time P = 0.99.

Cytokine Response during LPS Challenge

The 3 primary proinflammatory cytokines (IL-6, IL-1, and tumor necrosis factor) are responsible for the initiation of the acute-phase response in the body following infection and cause the body to develop a fever and inflammation. The secretion of IL-6 is linked to increases in core body temperature (Cartmell et al., 2000). Supplementation of TC decreased (P < 0.0001) serum concentrations of IL-6 after an LPS infusion compared with CON steers (Fig. 7). Interferon-γ is a cytokine with immunostimulatory and immunomodulatory effects, leading to greater activity of natural killer cells and enhanced stimulation of macrophages (Schroder et al., 2004). Concentrations of serum IFN-γ in the present study tended to be greater (P = 0.07) in TC compared with CON steers (Fig. 8) after an LPS infusion. The decreased secretion of IL-6 in TC compared with CON steers is consistent with the temperature data, in which rectal temperature was lesser in TC compared with CON steers. The increase in serum IFN-γ in TC compared with CON steers is consistent with an increased ability to fight off infection. Burdick Sanchez et al. (2013) observed that supplementing with YCW decreased serum IL-6 concentrations, but had no effect on serum IFN-γ. Buntyn et al. (2016b) found no differences in serum IL-6, but an increase in serum IFN-γ in steers supplemented with an active dried yeast compared with nonsupplemented steers. Buntyn et al. (2016a) reported that serum concentrations of both IL-6 and IFN-γ were lesser in steers receiving 5.0 g/d of a live yeast compared with steers that were not fed yeast. There is evidence that an increase in serum cytokine concentrations is correlated with increased protein catabolism in swine, specifically, IL-6 is associated with increases in tissue degradation, energy mobilization, fever, and a decrease in voluntary feed intake (Johnson, 1997). It is possible that the decreased IL-6 concentrations seen in many studies in response to yeast and/or YCW supplementation are responsible for greater DMI. The decreased IL-6 concentrations in TC compared with CON steers in the current study indicate that TC steers may have been able to fight the same disease challenge with a smaller stress response. Interferon-γ is known for its ability to interfere with virus multiplication and has antimicrobial and antiviral activity (Shtrichman and Samuel, 2001). Humans unable to produce IFN-γ are more vulnerable to mycobacterial infections (Ottenhoff et al., 2000), and mice with a disrupted IFN-γ gene cannot control disease and are subject to tissue destruction (Flynn et al., 1993). Interferon-γ is an important mediator of macrophage activation and contributes to the resistance of intracellular pathogens (Flynn et al., 1993). The increase in serum IFN-γ concentrations in TC relative to CON steers in the present study suggests that TC supplemented steers may have had a greater ability to fight disease through identification and elimination of pathogens.

Figure 7.

Figure 7.

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Serum concentrations of interleukin-6 in response to a lipopolysaccharide challenge (LPS; 0.5 µg/kg BW) at time 0 h in receiving steers fed diets for 63 d. CON = control, no yeast cell wall feed additive (n = 8). TC = a hydrolyzed mannan- and glucan-rich yeast fraction (Select-TC, Alltech Inc., Nicholasville, KY) fed at 13 g/steer daily (n = 8). Data are presented as least square means ± SEM. Post-LPS treatment P ≤ 0.0001; post-LPS treatment × time P = 0.99.

Figure 8.

Figure 8.

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Serum concentrations of interferon-γ in response to a lipopolysaccharide challenge (LPS; 0.5 µg/kg BW) at time 0 h in receiving steers fed diets for 63 d. CON = control, no yeast cell wall feed additive (n = 8). TC = a hydrolyzed mannan- and glucan-rich yeast fraction (Select-TC, Alltech Inc., Nicholasville, KY) fed at 13 g/steer daily (n = 8). Data are presented as least square means ± SEM. Post-LPS treatment P = 0.07; post-LPS treatment × time P = 0.70.

Overall Conclusions

Supplementation of newly received feedlot steers with a hydrolyzed mannan- and glucan-rich yeast fraction decreased serum IL-6, rectal temperature, and indicators of fat catabolism and increased serum IFN-γ concentrations in steers after an LPS challenge; however, supplementation of a hydrolyzed mannan- and glucan-rich yeast fraction did not alter the performance of receiving feedlot steers. These results suggest that supplementation of a hydrolyzed mannan- and glucan-rich yeast fraction may enhance overall health and allow cattle to better respond to immunologic stress, but this may not translate into increased performance in the conditions observed in this study. Further research into the mechanisms whereby hydrolyzed mannan- and glucan-rich yeast fractions impact pathogens in the GIT in feedlot cattle may be warranted.

Footnotes

1

Appreciation is extended to employees of the Purdue Beef Research and Teaching Center for help in conduction this research.

LITERATURE CITED

  1. AOAC 1990. Official methods of analysis. 15th ed. AOAC, Arlington, VA. [Google Scholar]
  2. Aragon S. N., Ribeiro F. R. B., Hosford A. D., Thompson A. J., Hergenreder J. E., Jennings M. A., Corley J. R., and Johnson B. J.. 2016. Influence of yeast cell wall supplementation during the finishing phase on feedlot steer performance, carcass characteristics and postmortem tenderness. Prof. Anim. Sci. 32:192–200. doi:10.15232/pas.2015-01417 [Google Scholar]
  3. Arthington J. D., Eichert S. D., Kunkle W. E., and Martin F. G.. 2003. Effect of transportation and commingling on the acute-phase protein response, growth, and feed intake of newly weaned beef calves. J. Anim. Sci. 81:1120–1125. doi:10.2527/2003.8151120x [DOI] [PubMed] [Google Scholar]
  4. Bernhard B. C., Burdick N. C., Rathmann R. J., Carroll J. A., Finck D. N., Jennings M. A., Young T. R., and Johnson B. J.. 2012. Chromium supplementation alters both glucose and lipid metabolism in feedlot cattle during the receiving period. J. Anim. Sci. 90:4857–4865. doi:10.2527/jas.2011-4982 [DOI] [PubMed] [Google Scholar]
  5. Broadway P. R., Carroll J. A., and Sanchez N. C.. 2015. Live yeast and yeast cell wall supplements enhance immune function and performance in food-producing livestock: A review†,‡. Microorganisms 3:417–427. doi:10.3390/microorganisms3030417 [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Buntyn J. O., Carroll J. A., Burdick Sanchez N. C., Sieren S. E., Bittner C. J., Burken D. B., Erickson G. E., Jones S. J., and Schmidt T. B.. 2016a. Yeast supplementation alters the immune response in feedlot steers. Nebr. Beef Cattle Rep. MP103:99–101. [Google Scholar]
  7. Buntyn J. O., Sieren S. E., Bittner C. J., Burken D. B., Erickson G. E., Burdick Sanchez N. C., Carroll J. A., Jones S. J., Schmidt T. B.,. et al. 2016b. Effects of feeding OmniGen-AF on immune function, performance, and carcass characteristics during the feeding period. Nebr. Beef Cattle Rep. MP103:96–98. [Google Scholar]
  8. Burdick N. C., Bernhard B. C., Carroll J. A., Rathmann R. J., and Johnson B. J.. 2012. Enhancement of the acute phase response to a lipopolysaccharide challenge in steers supplemented with chromium. Innate Immun. 18:592–601. doi:10.1177/1753425911428964 [DOI] [PubMed] [Google Scholar]
  9. Burdick Sanchez N. C., Young T. R., Carroll J. A., Corley J. R., Rathmann R. J., and Johnson B. J.. 2013. Yeast cell wall supplementation alters aspects of the physiological and acute phase responses of crossbred heifers to an endotoxin challenge. Innate Immun. 19:411–419. doi:10.1177/1753425912469673 [DOI] [PubMed] [Google Scholar]
  10. Burdick Sanchez N. C., Young T. R., Carroll J. A., Corley J. R., Rathmann R. J., and Johnson B. J.. 2014. Yeast cell wall supplementation alters the metabolic responses of crossbred heifers to an endotoxin challenge. Innate Immun. 20:104–112. doi:10.1177/1753425913482152 [DOI] [PubMed] [Google Scholar]
  11. Calder P. C., Dimitriadis G., and Newsholme P.. 2007. Glucose metabolism in lymphoid and inflammatory cells and tissues. Curr. Opin. Clin. Nutr. Metab. Care 10:531–540. doi:10.1097/MCO.0b013e3281e72ad4 [DOI] [PubMed] [Google Scholar]
  12. Cartmell T., Poole S., Turnbull A. V., Rothwell N. J., and Luheshi G. N.. 2000. Circulating interleukin-6 mediates the febrile response to localised inflammation in rats. J. Physiol. 526(Pt 3):653–661. doi:10.1111%2Fj.1469-7793.2000.00653.x [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Cole N. A., Purdy C. W., and Hutcheson D. P.. 1992. Influence of yeast culture on feeder calves and lambs. J. Anim. Sci. 70:1682–1690. doi:10.2527/1992.7061682x [DOI] [PubMed] [Google Scholar]
  14. Diaz D. E., Hagler W. M. Jr, Blackwelder J. T., Eve J. A., Hopkins B. A., Anderson K. L., Jones F. T., and Whitlow L. W.. 2004. Aflatoxin binders II: Reduction of aflatoxin M1 in milk by sequestering agents of cows consuming aflatoxin in feed. Mycopathologia 157:233–241. doi:10.1023/B:MYCO.0000020587.93872.59 [DOI] [PubMed] [Google Scholar]
  15. Duff G. C., and Galyean M. L.. 2007. Board-invited review: Recent advances in management of highly stressed, newly received feedlot cattle. J. Anim. Sci. 85:823–840. doi:10.2527/jas.2006-501 [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Ellenberger M. A., Johnson D. E., Carstens G. E., Hossner K. L., Holland M. D., Nett T. M., and Nockels C. F.. 1989. Endocrine and metabolic changes during altered growth rates in beef cattle. J. Anim. Sci. 67:1446–1454. doi:10.2527/jas1989.6761446x [DOI] [PubMed] [Google Scholar]
  17. Elsasser T. H., Caperna T. J., Li C. J., Kahl S., and Sartin J. L.. 2008. Critical control points in the impact of the proinflammatory immune response on growth and metabolism. J. Anim. Sci. 86(14 Suppl):E105–E125. doi:10.2527/jas.2007-0634 [DOI] [PubMed] [Google Scholar]
  18. FASS 2010. Guide for the care and use of agricultural animals in research and teaching. 3rd ed. Fed. Anim. Sci. Soc, Champaign, IL. [Google Scholar]
  19. Finck D. N., Ribeiro F. R. B., Burdick N. C., Parr S. L., Carroll J. A., Young T. R., Bernhard B. C., Corley J. R., Estefan A. G., Rathmann R. J.,. et al. 2014. Yeast supplementation alters the performance and health status of receiving cattle. Prof. Anim. Sci. 30:333–341. doi:10.15232/S1080-7446(15)30125-X [Google Scholar]
  20. Flynn J. L., Chan J., Triebold K. J., Dalton D. K., Stewart T. A., and Bloom B. R.. 1993. An essential role for interferon gamma in resistance to Mycobacterium tuberculosis infection. J. Exp. Med. 178:2249–2254. doi:10.1084/jem.178.6.2249 [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Galyean M. L., Perino L. J., and Duff G. C.. 1999. Interaction of cattle health/immunity and nutrition. J. Anim. Sci. 77:1120–1134. doi:10.2527/1999.7751120x [DOI] [PubMed] [Google Scholar]
  22. Hasday J. D., Fairchild K. D., and Shanholtz C.. 2000. The role of fever in the infected host. Microbes Infect. 2:1891–1904. doi:10.1016/S1286-4579(00)01337-X [DOI] [PubMed] [Google Scholar]
  23. Helderman J. H. 1981. Role of insulin in the intermediary metabolism of the activated thymic-derived lymphocyte. J. Clin. Invest. 67:1636–1642. doi:10.1172/JCI110199 [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Johnson R. W. 1997. Inhibition of growth by pro-inflammatory cytokines: An integrated view. J. Anim. Sci. 75:1244–1255. doi:10.2527/1997.7551244x [DOI] [PubMed] [Google Scholar]
  25. Keyser S. A., McMeniman J. P., Smith D. R., MacDonald J. C., and Galyean M. L.. 2007. Effects of Saccharomyces cerevisiae subspecies boulardii CNCM I-1079 on feed intake by healthy beef cattle treated with florfenicol and on health and performance of newly received beef heifers. J. Anim. Sci. 85:1264–1273. doi:10.2527/jas.2006-751 [DOI] [PubMed] [Google Scholar]
  26. Lang C. H., Bagby G. J., and Spitzer J. J.. 1985. Glucose kinetics and body temperature after lethal and nonlethal doses of endotoxin. Am. J. Physiol. 248(4 Pt 2):R471–R478. doi:10.1152/ajpregu.1985.248.4.R471 [DOI] [PubMed] [Google Scholar]
  27. Lei C. L., Dong G. Z., Jin L., Zhang S., and Zhou J.. 2013. Effects of dietary supplementation of montmorillonite and yeast cell wall on lipopolysaccharide adsorption, nutrient digestibility and growth performance in beef cattle. Livest. Sci. 158:57–63. doi:10.1016/j.livsci.2013.08.019 [Google Scholar]
  28. Martin L. M., Wood K. M., McEwen P. L., Smith T. K., Mandell I. B., Yannikouris A., and Swanson K. C.. 2010. Effects of feeding corn naturally contaminated with Fusarium mycotoxins and/or a modified yeast cell wall extract on the performance, immunity and carcass characteristics of grain-fed veal calves. Anim. Feed Sci. Tech. 159:27–34. doi:10.1016/j.anifeedsci.2010.05.006 [Google Scholar]
  29. National Academies of Sciences, Engineering and Medicine (NASEM) 2016. Nutrient requirements of beef cattle. 8th rev. ed. The National Academies Press, Washington, DC: doi:10.17226/19014 [Google Scholar]
  30. Ottenhoff T. H., de Boer T., Verhagen C. E., Verreck F. A., and van Dissel J. T.. 2000. Human deficiencies in type 1 cytokine receptors reveal the essential role of type 1 cytokines in immunity to intracellular bacteria. Microbes Infect. 2:1559–1566. doi:10.1016/S1286-4579(00)01312-5 [DOI] [PubMed] [Google Scholar]
  31. Plaizier J. C., Khafipous E., Li S., Gozho G. N., and Krause D. O.. 2012. Subacute ruminal acidosis (SARA), endotoxins and health consequences. Anim. Feed Sci. Technol. 172:9–21. doi:10.1016/j.anifeedsci.2011.12.004 [Google Scholar]
  32. Pritchard R. H. 1993. Bunk management. In: Land O’Lakes Beef Seminar, Cedar Rapids, IA, Columbus, NE, and Storm Lake, IA Land O’Lakes Inc, St. Paul, MN: p. 4–15. [Google Scholar]
  33. Renaville R., Hammadi M., and Portetelle D.. 2002. Role of the somatotropic axis in the mammalian metabolism. Domest. Anim. Endocrinol. 23:351–360. doi:10.1016/S0739-7240(02)00170-4 [DOI] [PubMed] [Google Scholar]
  34. Roth J. A., and Kaeberle M. L.. 1982. Effect of glucocorticoids on the bovine immune system. J. Am. Vet. Med. Assoc. 180:894–901. [PubMed] [Google Scholar]
  35. Salinas-Chavira J., Arzola C., Gonzalex-Vizcarra V., Manríquez-Núñez O. M., Montaño-Gómez M. F., Navarrete-Reyes J. D., Raymundo C., and Zinn R. A.. 2015. Influence of feeding enzymatically hydrolyzed yeast cell wall on growth performance and digestive function of feedlot cattle during periods of elevated ambient temperature. Asian-Australas J. Anim. Sci. 28:1288–1295. doi:10.5713%2Fajas.15.0061 [DOI] [PMC free article] [PubMed] [Google Scholar]
  36. Salinas-Chavira J., Montano M. F., Torrentera N., and Zinn R. A.. 2017. Influence of feeding enzymatically hydrolysed yeast cell wall + yeast culture on growth performance of calf-fed Holstein steers. J. Appl. Anim. Res. doi:10.1080/09712119.2017.1299742 [Google Scholar]
  37. Sánchez-Mendoza B., Montelongo-Terriquez A., Plascencia A., Torrentera N., Ware R. A., and Zinn R. A.. 2015. Influence of feeding chromium-enriched enzymatically hydrolyzed yeast on growth performance, dietary energetics and carcass characteristics in feedlot cattle under conditions of high ambient temperature. J. Appl. Anim. Res. 43:390–395. doi:10.1080/09712119.2014.978781 [Google Scholar]
  38. Schroder K., Hertzog P. J., Ravasi T., and Hume D. A.. 2004. Interferon-gamma: An overview of signals, mechanisms and functions. J. Leukoc. Biol. 75:163–189. doi:10.1189/jlb.0603252 [DOI] [PubMed] [Google Scholar]
  39. Shtrichman R., and Samuel C. E.. 2001. The role of gamma interferon in antimicrobial immunity. Curr. Opin. Microbiol. 4:251–259. doi:10.1016/S1369-5274 (00)00199-5 [DOI] [PubMed] [Google Scholar]
  40. Spring P., Wenk C., Connolly A., and Kiers A.. 2015. A review of 733 published trials on Bio-Mos®, a mannan oligosaccharide, and Actigen®, a second generation mannose rich fraction, on farm and companion animals. J. Appl. Anim. Nutr. 3:1–11. doi:10.1017/jan.2015.6 [Google Scholar]
  41. Steiger M., Senn M., Altreuther G., Werling D., Sutter F., Kreuzer M., and Langhans W.. 1999. Effect of a prolonged low-dose lipopolysaccharide infusion on feed intake and metabolism in heifers. J. Anim. Sci. 77:2523–2532. doi:10.2527/1999.7792523x [DOI] [PubMed] [Google Scholar]
  42. Young T. R., Ribeiro F. R. B., Burdick Sanchez N. C., Carroll J. A., Jennings M. A., Cribbs J. T., Rathmann R. J., Corley J. R., and Johnson B. J.. 2017. Yeast cell wall supplementation alters the performance and health of beef heifers during the receiving period. Prof. Anim. Sci. 33:166–175. doi:10.15232/pas.2016-01511 [Google Scholar]
  43. Zhang S., Albornoz R. I., Aschenbach J. R., Barreda D. R., and Penner G. B.. 2013. Short-term feed restriction impairs the absorptive function of the reticulo-rumen and total tract barrier function in beef cattle. J. Anim. Sci. 91:1685–1695. doi:10.2527/jas.2012-5669 [DOI] [PubMed] [Google Scholar]

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