Effects of mannan-oligosaccharide and Bacillus subtilis supplementation to preweaning Holstein dairy heifers on body weight gain, diarrhea, and shedding of fecal pathogens

Effects of Bacillus subtilis on Growth Performance, Metabolic Profile, and Health Status in Dairy Calves

This study focused on assessing whether the inclusion of probiotics (B. subtilis) as feed additives during the preweaning stage can enhance the body weight and metabolic condition of neonatal calves. A total of 50 Holstein calves, all born on the same farm, were randomly divided into two homogeneous treatment groups after birth. The calves in the control group (CG) were fed a milk replacer (n = 25) (13 females and 12 males) and those in the B. subtilis-supplement-treated group (TG), (n = 25) (13 females and 12 males) were fed a milk replacer with 7.5 mL/calf/day of B. subtilis probiotic (complied with the manufacturer's guidelines). The probiotic was administered 24 h post-birth, signifying the start of the experimental period. It took one month to collect the animals. Body weight was measured at birth for all animals. A local veterinarian, working on the farm, conducted daily health checks of the calves, recording health parameters and any antibiotic treatments. Blood samples were collected from each calf at birth and 30, 60, and 90 days by puncturing the jugular vein using 10 mL evacuated serum tubes before morning feeding. Significant differences in body weight were observed between the CG and the TG at 30, 60, and 90 days of age. At 30 days, the TG had a 4.11% higher average body weight than the CG (54.38 kg vs. 52.71 kg). At 60 days, the TG's average weight was 3.75% higher (79.21 kg vs. 76.34 kg), and at 90 days, the TG had a 2.91% higher average weight (112.87 kg vs. 109.67 kg). At 30 days of age, the TG showed significantly lower AST activity, with a 41.12% decrease compared to the CG (51.02 IU/L vs. 72.00 IU/L). Conversely, GGT activity was significantly higher in the TG by 64.68% (40.64 IU/L vs. 14.35 IU/L). Phosphorus concentration at 30 days was also significantly higher in the TG by 9.36% (3.27 mmol/L vs. 2.99 mmol/L). Additionally, the TG had a significantly lower total protein concentration, with a 21.63% decrease at 30 days (46.32 g/L vs. 56.34 g/L) and a 20.28% decrease at 60 days (48.32 g/L vs. 58.12 g/L) compared to the CG. These findings indicate that dairy calves given conventional milk replacer along with a daily dose of 7.5 mL of B. subtilis probiotic experienced enhanced growth performance and a more favourable metabolic profile during the first 90 days of their lives.

Effects of supplementing direct-fed microbials on health and growth of preweaning Gyr × Holstein dairy calves

This study aimed to evaluate the effects of direct-fed microbials (DFM) on health and growth responses of preweaning Bos indicus × Bos taurus (Gyr × Holstein) crossbred calves. Ninety newborn heifer calves (initial BW of 35 ± 4.0 kg) were used. At birth, calves were ranked by initial BW and parity of the dam and assigned to: (1) whole milk without DFM supplementation (CON; n = 30), (2) whole milk with the addition of 1.0 g/calf per day of a Bacillus-based DFM (BAC; n = 30), or (3) whole milk with the addition of 1.0 g/calf per day of BAC and 1.2 g/calf per day of Enterococcus faecium 669 (MIX; n = 30). Milk was fed individually during the study (77 d), and the BAC and MIX treatments were offered daily throughout the 77-d preweaning period. All calves were offered a starter supplement and corn silage starting on d 1 and 60 of age, respectively. Milk and starter supplement intake were evaluated daily, and BW was recorded on d 0 and at weaning (d 77). Diarrhea and pneumonia were assessed daily, and fecal samples were collected on d 0, 7, 14, 21, and at weaning (d 77) for assessment of the presence of bacterial and protozoal pathogens via qPCR. All data were analyzed using SAS (v. 9.4) with calf as the experimental unit and using single-df orthogonal contrasts (BAC + MIX vs. CON; BAC vs. MIX). Daily feeding of DFM, regardless of type, improved weaning BW. Odds ratio for occurrence of pneumonia was lower for DFM-supplemented calves, but its occurrence did not differ between BAC and MIX calves. No Salmonella spp. or Escherichia coli F41 were detected in any of the calves. The proportion of calves positive for E. coli F17 was greater for DFM calves on d 7 (92% and 96% vs. 81% for BAC, MIX, and CON, respectively), on d 21 (13% and 26% vs. 7% for BAC, MIX, and CON, respectively), and at weaning (48% and 35% vs. 22% for BAC, MIX, and CON, respectively). For Clostridium difficile, more DFM calves were positive on d 7 (65% and 30% vs. 35% for BAC, MIX, and CON, respectively) and 14 (20% and 28% vs. 7% for BAC, MIX, and CON, respectively), but proportion of positive calves was also greater for BAC versus MIX on d 7. More CON calves were positive for Clostridium perfringens on d 14 (14% vs. 3% and 8% for CON, BAC, and MIX, respectively) compared with DFM-fed calves. Incidence of calves positive for C. perfringens was greater in BAC than MIX on d 7 (50% vs. 18%), and greater for MIX than BAC at weaning (9% vs. 0%). For protozoa occurrence, a lower proportion of DFM calves were positive for Cryptosporidium spp. on d 7 (58% and 48% vs. 76% for BAC, MIX, and CON, respectively), but opposite results were observed on d 21 for Cryptosporidium spp. (3% and 11% vs. 0% for BAC, MIX, and CON, respectively) and Eimeria spp. on d 14 (7% and 8% vs. 0% for BAC, MIX, and CON, respectively) and 21 (50% and 59% vs. 38% for BAC, MIX, and CON, respectively). In summary, DFM feeding alleviated the occurrence of pneumonia and improved growth rates, while also modulating the prevalence of bacteria and protozoa in preweaning Gyr × Holstein calves.

Effects of a multistrain Bacillus-based direct-fed microbial on gastrointestinal permeability and biomarkers of inflammation during and following feed restriction in mid-lactation Holstein cows

Objectives were to evaluate the effects of a multistrain Bacillus-based (Bacillus subtilis and Bacillus pumilus blend) direct-fed microbial (DFM) on production, metabolism, inflammation biomarkers and gastrointestinal tract (GIT) permeability during and following feed restriction (FR) in mid-lactation Holstein cows. Multiparous cows (n = 36; 138 ± 53 DIM) were randomly assigned to 1 of 3 dietary treatments: (1) control (CON; 7.5 g/d rice hulls; n = 12), (2) DFM10 (10 g/d Bacillus DFM, 4.9 × 109 cfu/d; n = 12) or 3) DFM15 (15 g/d Bacillus DFM, 7.4 × 109 cfu/d; n = 12). Before study initiation, cows were fed their respective treatments for 32 d. Cows continued to receive treatments during the trial, which consisted of 3 experimental periods (P): P1 (5 d) served as baseline for P2 (5 d), during which all cows were restricted to 40% of P1 DMI, and P3 (5 d), a "recovery" where cows were fed ad libitum. On d 4 of P1 and on d 2 and 5 of P2, GIT permeability was evaluated in vivo using the oral paracellular marker Cr-EDTA. As anticipated, FR decreased milk production, insulin, glucagon, and BUN but increased nonesterified fatty acids. During recovery, DMI rapidly increased on d 1 then subsequently decreased (4.9 kg) on d 2 before returning to baseline, whereas milk yield slowly increased but remained decreased (13%) relative to P1. The DFM10 cows had increased DMI and milk yield relative to DFM15 during P3 (10%). Overall, milk lactose content was increased in DFM cows relative to CON (0.10 percentage units), and DFM10 cows tended to have increased lactose yield relative to CON and DFM15 during P3 (8% and 10%, respectively). No overall treatment differences were observed for other milk composition variables. Circulating glucose was quadratically increased in DFM10 cows compared with CON and DFM15 during FR and recovery. Plasma Cr area under the curve was increased in all cows on d 2 (9%) and 5 (6%) relative to P1. Circulating LPS binding protein (LBP), serum amyloid A (SAA), and haptoglobin (Hp) increased in all cows during P2 compared with baseline (31%, 100%, and 9.0-fold, respectively). Circulating Hp concentrations continued to increase during P3 (274%). Overall, circulating LBP and Hp tended to be increased in DFM15 cows relative to DFM10 (29% and 81%, respectively), but no treatment differences were observed for SAA. Following feed reintroduction during P3, fecal pH initially decreased (0.62 units), but returned to baseline levels whereas fecal starch markedly increased (2.5-fold) and remained increased (82%). Absolute quantities of a fecal Butyryl-CoA CoA transferase (but) gene associated with butyrate synthesis, collected by fecal swab were increased in DFM10 cows compared with CON and DFM15 cows. In summary, FR increased GIT permeability, caused inflammation, and decreased production. Feeding DFM10 increased some key production and metabolism variables and upregulated a molecular biomarker of microbial hindgut butyrate synthesis, while DFM15 appeared to augment immune activation.

Supplementing a Bacillus-based direct-fed microbial improves feed efficiency in lactating dairy cows

This experiment was conducted to evaluate the effects of feeding a Bacillus-based direct-fed microbial (DFM) on performance and nutrient digestibility of lactating dairy cows. Seventy-six lactating (42 ± 6 days in milk [DIM]) Holstein-Friesian primiparous and multiparous cows were enrolled to a 16-wk experiment. Cows were blocked by lactation number and DIM and within blocks, assigned to 1 of the 2 treatments: 1) basal partial-mixed ration (PMR) without DFM addition (n = 38; CON) or 2) basal PMR with the addition of 3 g/head/d of a DFM containing B. licheniformis 809 and B. subtilis 810 (n = 38; BOVACILLUS, Chr. Hansen A/S, Hørsholm, Denmark; DFM). The DFM was mixed in a protein-based pellet, whereas the CON group was fed the same pellet without DFM (0.6 kg/cow/d). The PMR contained (dry matter [DM] basis) 50% of forage and 48% of a concentrate feed based on corn meal, soybean meal, wheat meal, wheat middlings, and a mineral-vitamin premix, with the remaining part of the diet being represented by the pellet used as a carrier for the treatments (CON and DFM). Dry matter intake (DMI), milk yield, and production efficiency were recorded daily, whereas milk protein and fat concentrations were recorded using electronic milk meters. An additional milk sample was collected every second week of the study for milk composition. On week 15 of the study, fecal samples were collected from each cow for apparent nutrient digestibility calculation. All data were analyzed using the MIXED procedure of SAS (version 9.4; SAS Inst. Inc., Cary, NC). No treatment effects were observed on cow final body weight, daily DMI, milk yield, energy-corrected milk (ECM), ECM efficiency, milk composition (yield or content), and somatic cell count (SCC) (P ≥ 0.12). However, cows fed DFM had a greater feed and N efficiency (P ≤ 0.03) compared to cows fed CON. Moreover, DM digestibility tended to be greater for DFM-fed cows when compared to CON (P = 0.10), whereas no further nutrient digestibility differences were observed (P ≥ 0.24). In summary, supplementing a DFM containing Bacillus licheniformis and B. subtilis benefited feed efficiency of lactating dairy cows fed a PMR, while also tending to improve the digestibility of DM.

Effects of Bacillus subtilis on in vitro ruminal fermentation and methane production

The objective of this study was to evaluate the effect of a proprietary strain of a Bacillus subtilis on in vitro ruminal fermentation and methane production in batch culture serum bottles. One hundred forty-nine batch culture bottles were used in a complete randomized block design. The arrangement of treatments was a 3 × 3 × 4 factorial to evaluate the effects of inoculum, time, diet, and their respective interactions. There were three experimental runs total, where the run was used as block. Inoculum treatments were 1.85 mg/mL of microcrystalline cellulose (CON); 10 billion B. subtilis plus microcrystalline cellulose (A1); and 60 billion B. subtilis plus microcrystalline cellulose (A2). Diet treatments were 0.50 g of early lactation diet (E, 30% starch), mid-lactation diet (M, 25% starch), or dry cow diet (D, 18% starch). The combination resulted in total of nine treatments. Each treatment had five replicates, two of which were used to determine nutrient degradability at 24 and 48 h after inoculation, and three were used to determine pH, ammonia nitrogen (NH3-N), volatile fatty acids, lactate, total gas, and methane production at 3, 6, 24, and 48 h after inoculation. Fixed effects of inoculum, diet, and their interaction were tested using the GLIMMIX procedure of SAS. Significance was declared at P ≤ 0.05. We observed that, compared to control, the supplementation of B. subtilis, decreased the production of acetate and propionate, while increasing the production of butyrate, iso-butyrate, valerate, iso-valerate, and caproate within each respective diet. Additionally, the total methane production exhibited mixed responses depending on the diet type. Overall, the inclusion of B. subtilis under in vitro conditions shows the potential to reduce ruminal methane production when supplemented with a mid-lactation diet, constituting a possible methane mitigation additive for dairy cattle diets.

Impact of synbiotics on growth performance and gut health in Murrah buffalo calves

Synbiotics have been used as biotherapeutic supplements for prevention of new-born calf gastrointestinal disorders. Present study was conducted to evaluate the impact of fructo-oligosaccharide, mannan-oligosaccharide and inulin along with Lactobacillus plantarum CRD-7 and Lactobacillus acidophilus NCDC15 on the nutrient digestibility, growth performance and faecal microbial population of pre-ruminant buffalo calves. Twenty-four Murrah calves (5 days old) were randomly assigned to four groups of six calves in each using randomized block design. Calves in Group I (control) received only a basic diet of milk, calf starter and berseem with no additives. Calves in Group II (SYN1) were fed 6 g fructo-oligosaccharide (FOS) + Lactobacillus plantarum CRD-7 (100 ml). Calves in Group III (SYN2) were fed 9 g inulin + L. plantarum CRD-7 (50 ml), while calves in Group IV (SYN3) received 4 g MOS + L. acidophilus NCDC15 (200 ml) as fermented milk having 108 CFU/ml/calf/day in addition to the basal diet. The results revealed that digestibility of dry matter, crude protein, ether extract and average daily gain were all higher (P < 0.05) in SYN1 as compared to control group. The antioxidant enzyme activity, humoral and cell mediated immunity performed well in SYN1, SYN2 and SYN3 as compared to control. Diarrhoea and faecal scouring were lower (P < 0.05) in all supplemented groups than control. Faecal Lactobacilli and Bifidobacterium counts were also higher in SYN1 group followed by SYN2 and SYN3. Faecal ammonia, lactate, pH, and volatile fatty acids level were increased in SYN1 supplemented groups. The synbiotic combination of 6 g FOS + L. plantarum CRD-7 had better response on digestibility, average daily gain, antioxidant enzymes, immune response, faecal microbiota and metabolites and also reduce the faecal score and diarrhoea incidence. Therefore, supplementation of 6 g FOS + L. plantarum CRD-7 can be advised for general use in order to promote long-term animal production.

Effects of supplementing a direct-fed microbial containing Enterococcus faecium 669 on performance, health, and metabolic responses of preweaning Holstein dairy calves

This study aimed to evaluate the effects of Enterococcus faecium 669 supplementation on performance, health, parasitological, microbiological, and hematological responses of preweaning dairy calves. Forty-two newborn Holstein female calves (initial body weight [BW] 44 ± 4.5 kg) were used in the present study. At birth, calves were ranked by initial BW and assigned to 1 of 2 treatment groups: (1) whole milk (CON; n = 21) and (2) whole milk with the addition of direct-fed microbial Ent. faecium 669 (DFM; n = 21). During the entire experimental period (63 d), DFM was daily-fed at a rate of 2.5 × 109 cfu/head. All calves were offered a mixture of a starter feed and wheat straw for ad libitum consumption. Supplement intake was evaluated daily, whereas calves were weighed on a weekly basis from d 0 to weaning (d 63). Diarrhea was assessed once a day, and fecal and blood samples were collected for microbiological, parasitological, and hematological responses. All data were analyzed with SAS using calf as the experimental unit. A treatment × week interaction was observed for BW, as DFM-supplemented calves were heavier than CON cohorts on d 56 (+ 4.7 kg) and at weaning on d 63 (+ 4.8 kg). A similar interaction was observed for average daily gain (ADG) and dry matter intake (DMI), with greater ADG for DFM-supplemented calves from d 35 to 42, greater ADG and DMI from d 49 to 56, and greater DMI from d 56 to weaning. Moreover, diarrhea occurrence tended to be lower, whereas rectal temperature was 0.2°C lower for DFM-supplemented calves. Treatment × day interactions were observed for the occurrence and counts of Eimeria spp., as DFM-supplemented calves tended to have a reduced number of positive observations on d 42 of the study versus CON, and a significant reduction in positive animals from d 21 to 42 was observed in the DFM group but not in CON calves. For Cryptosporidium spp., no treatment effects were observed on overall occurrence (%), but DFM-supplemented calves had a greater count of oocyst per gram versus CON. No treatment × day interaction or main treatment effects were observed for any of the blood variables analyzed herein, exception being monocytes concentration. In summary, preweaning Ent. faecium 669 supplementation improved performance, diarrhea occurrence, and reduced the number of calves positively-detected for Eimeria spp.

The Effect of Probiotics in a Milk Replacer on Leukocyte Differential Counts, Phenotype, and Function in Neonatal Dairy Calves

Probiotics have been investigated for many health benefits; however, few studies have been performed to determine the effects of oral probiotics on peripheral blood and respiratory immune cells in cattle. Our objectives were to determine changes in health and growth status, differential blood cell counts and function, and blood and lung cell function using flow cytometry and PCR in dairy calves fed a milk replacer with (PRO, N = 10) or without (CON, N = 10) the addition of probiotics to the milk replacer and dry rations from birth to weaning. Performance and clinical scores were not different between the treatment groups. Treatment-by-day interactions for peripheral blood leukocyte populations differed in cell number and percentages. A greater percentage of leukocytes expressed the cell surface markers CD3, CD4, CD8, CD11b, and CD205 on d 21 in CON animals. Lung lavages were performed on five animals from each treatment group on d 52. There were no differences between treatment groups for the expression of cytokines and Toll-Like Receptors as measured using Polymerase Chain Reaction, possibly due to the small sample size. Oral probiotics appear to affect peripheral blood immune cells and function. Their effect on overall calf health remains to be determined.

Effects of Saccharomyces cerevisiae live cells and culture on growth and productive performance in lactating Nili-Ravi buffaloes

An experimental work was conducted to evaluate the effects of Saccharomyces cerevisiae live cells and its culture on dry matter intake (DMI), milk yield, milk composition, body condition score, selected blood metabolites, feed conversion efficiency (FCE), nutrient digestibility, body weight gain, and economics of milk production in lactating multiparous Nili-Ravi buffaloes. In total, 20 buffaloes of age 5 years ± 6 months and weighing 550 ± 20 kg were selected and assigned to four dietary treatments (n=5 buffalo/treatment) under completely randomized design. The dietary treatments include treatment 1 (T1) control, treatment 2 (T2) 5g/head live yeast, treatment 3 (T3) 5g/head yeast culture, and treatment 4 (T4) 10 g/head yeast culture per day for 60 days excluding 14 days as an adjustment period. The results indicated that T4 showed significant (p<0.05) improvement in DMI, milk yield and components, blood glucose level, digestibility of nutrients, and body weight gain while significant decrease in blood urea nitrogen as compared to other treatment groups. Body condition score was not affected among treatments. In conclusion, yeast culture supplementation significantly improved (p <0.05) milk yield, milk composition, DMI, body weight gain, blood glucose level, and digestibility while significantly decreased blood urea level as compare to control. Economic return was also improved. BCS was not improved. Comparatively, yeast culture showed significant improvement in growth and productive performance as compare to live yeast. Meanwhile, 10-g yeast culture showed better results as compare to 5-g yeast culture.

Stability of Bacillus and Enterococcus faecium 669 Probiotic Strains When Added to Different Feed Matrices Used in Dairy Production

Few data are available evaluating the stability of direct-fed microbials (DFM) following their inclusion in different feed matrices. Therefore, six Exp. evaluated the recovery of bacilli spores (BOVACILLUS^TM; Exp. 1 to 3) and an Enterococcus faecium DFM (LACTIFERM^®; Exp. 4 to 6) when included in different feed preparations. The Bacillus-based DFM was included into pelleted feed prepared in different temperatures (75 to 95 °C), whereas both DFM were assessed in premix and milk replacer preparations. Bacillus spores and E. faecium recovery was evaluated through standard methodologies and data were reported as log10 colony forming units/gram of feed. The recovery of Bacillus spores was within the expected range and was not impacted by the temperature of pellet preparation (Exp. 1). Bacilli recovery was also stable up to 12 months in the premix and was not impacted by the temperature of milk replacer preparation. Regarding the Exp. with E. faecium (Exp. 4 to 6), its recoveries in the mineral premix and milk powder did not differ from T0 and were not impacted by the conditions of milk replacer preparation. These data are novel and demonstrate the stability of a Bacillus-based and an E. faecium-based DFM when included in different feed matrices often used in dairy production.

Effect of synbiotics on growth performance, gut health, and immunity status in pre-ruminant buffalo calves

Synbiotics are employed as feed additives in animal production as an alternate to antibiotics for sustaining the gut microbiota and providing protection against infections. Dairy calves require a healthy diet and management to ensure a better future for the herd of dairy animals. Therefore, the present study was carried out to investigate the effect of synbiotics formulation on growth performance, nutrient digestibility, fecal bacterial count, metabolites, immunoglobulins, blood parameters, antioxidant enzymes and immune response of pre-ruminant Murrah buffalo calves. Twenty-four apparently healthy calves (5 days old) were allotted into four groups of six calves each. Group I (control) calves were fed a basal diet of milk, calf starter and berseem with no supplements. Group II (SYN1) calves were fed with 3 g fructooligosaccharide (FOS) + Lactobacillus plantarum CRD-7 (150 ml). Group III (SYN2) calves were fed with 6 g FOS + L. plantarum CRD-7 (100 ml), whereas calves in group IV (SYN3) received 9 g FOS + L. plantarum CRD-7 (50 ml). The results showed that SYN2 had the highest (P < 0.05) crude protein digestibility and average daily gain compared to the control. Fecal counts of Lactobacilli and Bifidobacterium were also increased (P < 0.05) in supplemented groups as compared to control. Fecal ammonia, diarrhea incidence and fecal scores were reduced in treated groups while lactate, volatile fatty acids and antioxidant enzymes were improved compared to the control. Synbiotic supplementation also improved both cell-mediated and humoral immune responses in buffalo calves. These findings indicated that synbiotics formulation of 6 g FOS + L. plantarum CRD-7 in dairy calves improved digestibility, antioxidant enzymes, and immune status, as well as modulated the fecal microbiota and decreased diarrhea incidence. Therefore, synbiotics formulation can be recommended for commercial use in order to achieve sustainable animal production.

Nondigestible Functional Oligosaccharides: Enzymatic Production and Food Applications for Intestinal Health

Nondigestible functional oligosaccharides are of particular interest in recent years because of their unique prebiotic activities, technological characteristics, and physiological effects. Among different types of strategies for the production of nondigestible functional oligosaccharides, enzymatic methods are preferred owing to the predictability and controllability of the structure and composition of the reaction products. Nondigestible functional oligosaccharides have been proved to show excellent prebiotic effects as well as other benefits to intestinal health. They have exhibited great application potential as functional food ingredients for various food products with improved quality and physicochemical characteristics. This article reviews the research progress on the enzymatic production of several typical nondigestible functional oligosaccharides in the food industry, including galacto-oligosaccharides, xylo-oligosaccharides, manno-oligosaccharides, chito-oligosaccharides, and human milk oligosaccharides. Moreover, their physicochemical properties and prebiotic activities are discussed as well as their contributions to intestinal health and applications in foods.

Bacterial composition of a competitive exclusion product and its correlation with product efficacy at reducing Salmonella in poultry

The mature intestinal microbiome is a formidable barrier to pathogen colonization. Day-old chicks seeded with cecal contents of adult hens are resistant to colonization with Salmonella, the basis of competitive exclusion. Competitive exclusion products can include individual microbes but are commonly undefined intestinal communities taken from adult animals and in commercial production is amplified in fermentator and sold commercially in freeze dried lots. While superior to single and multiple species probiotics, reducing Salmonella colonization by multiple logs, undefined products have limited acceptance because of their uncharacterized status. In this study, the bacterial composition of the master stock, preproduction seed stocks and commercial lots of a poultry competitive exclusion product, was defined by 16S rRNA sequence analysis, targeting the 16S rRNA variable region (V1-V3). The samples contained a diversity of genera (22-52 distinct genera) however, the commercial lots displayed less diversity compared to the seeds and the master stock. Community composition varied between seeds and the master stock and was not a good predictor of potency, in terms of log₁₀ reduction in Salmonella abundance. While there was significant correlation in composition between seeds and their commercial lots, this too was a not a good predictor of potency. There was linear correlation between unclassified Actinobacteria, Peptococcus, and unclassified Erysipelotrichaceae, and Salmonella abundance (r ² > .75) for commercial seeds. However, upon review of the literature, these three genera were not consistently observed across studies or between trials that examined the correlation between intestinal community composition and Salmonella prevalence or abundance.

Host innate immune responses and microbiome profile of neonatal calves challenged with Cryptosporidium parvum and the effect of bovine colostrum supplementation

Introduction

Calves are highly susceptible to gastrointestinal infection with Cryptosporidium parvum (C. parvum), which can result in watery diarrhea and eventually death or impaired development. With little to no effective therapeutics, understanding the host's microbiota and pathogen interaction at the mucosal immune system has been critical to identify and test novel control strategies.

Methods

Herein, we used an experimental model of C. parvum challenge in neonatal calves to describe the clinical signs and histological and proteomic profiling of the mucosal innate immunity and microbiota shifts by metagenomics in the ileum and colon during cryptosporidiosis. Also, we investigated the impact of supplemental colostrum feeding on C. parvum infection.

Results

We showed that C. parvum challenged calves experienced clinical signs including pyrexia and diarrhea 5 days post challenge. These calves showed ulcerative neutrophil ileitis with a proteomic signature driven by inflammatory effectors, including reactive oxygen species and myeloperoxidases. Colitis was also noticed with an aggravated mucin barrier depletion and incompletely filled goblet cells. The C. parvum challenged calves also displayed a pronounced dysbiosis with a high prevalence of Clostridium species (spp.) and number of exotoxins, adherence factors, and secretion systems related to Clostridium spp. and other enteropathogens, including Campylobacter spp., Escherichia sp., Shigella spp., and Listeria spp. Daily supplementation with a high-quality bovine colostrum product mitigated some of the clinical signs and modulated the gut immune response and concomitant microbiota to a pattern more similar to that of healthy unchallenged calves.

Discussion

C. parvum infection in neonatal calves provoked severe diarrheic neutrophilic enterocolitis, perhaps augmented due to the lack of fully developed innate gut defenses. Colostrum supplementation showed limited effect mitigating diarrhea but demonstrated some clinical alleviation and specific modulatory influence on host gut immune responses and concomitant microbiota.

Host-specific probiotics feeding influence growth, gut microbiota, and fecal biomarkers in buffalo calves

The current study is aimed to evaluate the effect of host-specific probiotics on the gut microbiome, performance, and select fecal biomarkers of gut health in preruminant buffalo calves. Eight Murrah buffalo calves (3–5 days old; 32.52 ± 0.43 kg average body weight (BW)) were randomly allocated into two groups as follows; 1) Group I (n = 4) fed basal diet alone (CON); 2) Group II (n = 4) supplemented with a lyophilized probiotic formulation at a dose rate of 1 g/day/head (1 × 10⁹ CFU/g) having Limosilactobacillus reuteri BF-E7 and Ligilactobacillus salivarius BF-17 along with basal diet (PF) for 30 days. Results revealed that final BW (kg), average daily gain (g/day), average dry matter intake (g/day), and structural growth measurements were significantly (P < 0.05) increased in the probiotics supplemented group (PF) compared to the control (CON). Fecal pH, fecal moisture, and fecal score were reduced (P < 0.05) in PF than in CON. Moreover, levels of fecal propionate, lactate, and ammonia altered positively in PF compared with CON. The relative abundance of Firmicutes tended to be higher (P = 0.10) in the probiotics fed group than CON. However, the relative abundance of Proteobacteria was significantly lower (P = 0.03) for calves fed probiotics on day 15. A trend was observed in Bacteroides (P = 0.07) and Lactobacillus (P = 0.08) abundances in the feces of the PF than in CON. Overall, it can be concluded that the administration of probiotic formulations significantly improved the performance and gut health of buffalo calves via modulating the gut microbiota composition.

Impact of Probiotics on Dairy Production Efficiency

There has been growing interest on probiotics to enhance weight gain and disease resistance in young calves and to improve the milk yield in lactating animals by reducing the negative energy balance during the peak lactation period. While it has been well established that probiotics modulate the microbial community composition in the gastrointestinal tract, and a probiotic-mediated homeostasis in the rumen could improve feed conversation competence, volatile fatty acid production and nitrogen flow that enhances the milk composition as well as milk production, detailed changes on the molecular and metabolic level prompted by probiotic feed additives are still not understood. Moreover, as living biotherapeutic agents, probiotics have the potential to directly change the gene expression profile of animals by activating the signalling cascade in the host cells. Various direct and indirect components of probiotic approaches to improve the productivity of dairy animals are discussed in this review.

Effects of a Bacillus-based direct-fed microbial on in vitro nutrient digestibility of forage and high-starch concentrate substrates

Two experiments evaluated the effects of a Bacillus-based direct-fed microbial (DFM) on in vitro dry matter (DM) and neutral detergent fiber (NDF; experiment 1) and starch (experiment 2) digestibility of a variety of ruminant feedstuffs. In experiment 1, 10 forage sources were evaluated: ryegrass, alfalfa hay, leucaena, corn silage, spinifex, buffel grass, flinders grass, Mitchell grass, Rhodes grass hay, and Queensland bluegrass. Experimental treatments were control (forages with no probiotic inoculation; CON) and forage sources inoculated with a mixture containing Bacillus licheniformis and Bacillus subtilis (3.2 × 10⁹ CFU per g; DFM). In vitro DM and NDF digestibility were evaluated at 24- and 48-h post-treatment inoculation. Treatment × hour interactions were noted for IVDMD (in vitro dry matter digestibility) and IVNDFD (in vitro neutral detergent fibre digestibility) (P ≤ 0.05). More specifically, DFM inoculation increased (P ≤ 0.03) IVDMD at 24 h in four forages and increased 48-h IVDMD (P ≤ 0.02) in alfalfa hay, ryegrass, leucaena, and Mitchell grass hay, but opposite results were observed for Queensland bluegrass (P < 0.01). A 24- and 48-h IVNDFD increased following DFM inoculation (P ≤ 0.02) in five forage sources, but reduced for Queensland bluegrass (P < 0.01). When the forages were classified according to their quality, main treatment effects were detected for IVDMD (P ≤ 0.02) and IVNDFD (P < 0.01). In experiment 2, five common cereal grains were evaluated—high-density barley (82 g/100 mL), low-density barley (69 g/100 mL), corn, sorghum, and wheat—under the same treatments as in experiment 1. In vitro starch digestibility (IVSD) was evaluated at 6- and 12-h following treatment inoculation. Treatment × hour interactions were observed for starch digestibility in three out of five concentrate sources (P ≤ 0.001). Inoculation of DFM yielded greater 24-h starch digestibility for high-, low-density barley, and wheat (P ≤ 0.02), but also greater at 48 h in wheat (P < 0.0001). Moreover, mean starch digestibility improved for corn and sorghum inoculated with DFM (P < 0.01). Using a Bacillus-based DFM (B. licheniformis and B. subtilis) improved the mean in vitro DM and NDF digestibility of different forage sources of varying qualities (based on crude protein content). Similarly, IVSD was also greater following DFM inoculation, highlighting the potential of this probiotic to improve nutrient digestibility and utilization in the beef and dairy cattle herd.

Supplementing Mannan Oligosaccharide Reduces the Passive Transfer of Immunoglobulin G and Improves Antioxidative Capacity, Immunity, and Intestinal Microbiota in Neonatal Goats

Successful establishment of passive immunity (PIT) and regulation of intestinal microbiota are crucial for ruminants to maintain body health and reduce the risk of disease during the neonatal period. Thus, the objective of this study was to investigate the effects of mannan oligosaccharide (MOS) supplementation on passive transfer of immunoglobulin G (IgG), serum inflammatory cytokines and antioxidant levels as well as bacteria composition in the ileal digesta. A total of 14 healthy neonatal Ganxi black goats with similar birth weight (BW: 2.35 ± 0.55 kg) were selected and allocated into two groups, only fed colostrum and milk replacer (CON, n = 7) and supplemented MOS (0.06% of birth BW) in the colostrum and milk replacer (MOS, n = 7). The results indicated that MOS supplementation significantly reduced (p < 0.05) serum IgG level at 3 and 6 h after colostrum feeding. Serum GLP-1 level of goats in the MOS group was significantly lower (p = 0.001) than that in the CON group. Goats in the MOS group had higher serum CAT and lower MDA level than those in the CON group (p < 0.05). Serum anti-inflammatory cytokine level of interleukin 4 (IL-4) was increased (p < 0.05), while pro-inflammatory cytokine IL-6 level was reduced (p < 0.05) in the MOS group when compared with the CON group. In addition, MOS supplementation remarkably increased (p < 0.05) the level of secretory IgA (sIgA) in the ileal digesta. Principal coordinate analysis of 16S rRNA sequence based on Brinary jaccard, Bray curtis, and weighted UniFrac distance of ileal microbiota showed a distinct microbial differentiation between the CON and MOS groups (p < 0.05). The relative abundance of Firmicutes in the MOS group was higher than that in the CON group, while the abundance of Verrucomicrobia was lower in the MOS group than that in the CON group at the phylum level (p < 0.05). The relative abundance of Proteobacteria tended to decrease (p = 0.078) in the MOS group at the phylum level. The results of LEfSe analysis showed that MOS group was characterized by a higher relative abundance of Lactobacillus, while the CON group was represented by a higher relative abundance of Akkermansia and Ruminiclostridium_5. Our findings demonstrated that MOS supplementation during the neonatal period increases antioxidant capacity and reduces the inflammatory response, and promotes IgA secretion and Lactobacillus colonization in the ileum. Thus, MOS induced positive effects are more pronounced in neonatal goats that might be an effective approach to maintain intestinal health and improve the surviving rate of neonatal ruminants.

Establishment of a Newborn Lamb Gut-Loop Model to Evaluate New Methods of Enteric Disease Control and Reduce Experimental Animal Use

Enteric infectious diseases are not all well controlled, which leads to animal suffering and sometimes death in the most severe cases, in addition to economic losses for farmers. Typical symptoms of enteric infections include watery diarrhea, stomach cramps or pain, dehydration, nausea, vomiting, fever and weight loss. Evaluation of new control methods against enteric infections requires the use of many animals. We aimed to develop a new method for an initial in vivo screen of promising compounds against neonatal diseases such as cryptosporidiosis while limiting experimental animal use. We therefore adapted an in vivo method of multiple consecutive but independent intestinal loops to newborn lambs delivered by cesarean section, in which endotoxin responsiveness is retained. This new method allowed for the screening of natural yeast fractions for their ability to stimulate immune responses and to limit early Cryptosporidium parvum development. This model may also be used to investigate host–pathogen interactions and immune responses in a neonatal controlled environment.

Review: The development of the gastrointestinal tract microbiota and intervention in neonatal ruminants

The complex microbiome colonizing the gastrointestinal tract (GIT) of ruminants plays an important role in the development of the immune system, nutrient absorption and metabolism. Hence, understanding GIT microbiota colonization in neonatal ruminants has positive impacts on host health and productivity. Microbes rapidly colonize the GIT after birth and gradually develop into a complex microbial community, which allows the possibility of GIT microbiome manipulation to enhance newborn health and growth and perhaps induce lasting effects in adult ruminants. This paper reviews recent advances in understanding how host-microbiome interactions affect the GIT development and health of neonatal ruminants. Following initial GIT microbiome colonization, continuous exposure to host-specific microorganisms is necessary for GIT development and immune system maturation. Furthermore, the early GIT microbial community structure is significantly affected by early life events, such as maternal microbiota exposure, dietary changes, age and the addition of prebiotics, probiotics and synbiotics, supporting the idea of microbial programming in early life. However, the time window in which interventions can optimally improve production and reduce gastrointestinal disease as well as the role of key host-specific microbiota constituents and host immune regulation requires further study.