The addition of curcumin to the diet of post-weaning dairy calves: effects on ruminal fermentation, immunological, and oxidative responses

Incorporating Curcumin into animal diets holds significant promise for enhancing both animal health and productivity, with demonstrated positive impacts on antioxidant activity, anti-microbial responses. Therefore, this study aimed to determine whether adding Curcumin to the diet of dairy calves would influence ruminal fermentation, hematologic, immunological, oxidative, and metabolism variables. Fourteen Jersey calves were divided into a control group (GCON) and a treatment group (GTRA). The animals in the GTRA received a diet containing 65.1 mg/kg of dry matter (DM) Curcumin (74% purity) for an experimental period of 90 days. Blood samples were collected on days 0, 15, 45, and 90. Serum levels of total protein and globulins were higher in the GTRA group (P < 0.05) than the GCON group. In the GTRA group, there was a reduction in pro-inflammatory cytokines (IL-1ß and IL-6) (P < 0.05) and an increase in IL-10 (which acts on anti-inflammatory responses) (P < 0.05) when compared to the GCON. There was a significantly higher (P < 0.05) concentration of immunoglobulin A (IgA) in the serum of the GTRA than the GCON. A Treatment × Day interaction was observed for haptoglobin levels, which were higher on day 90 in animals that consumed Curcumin than the GCON (P < 0.05). The catalase and superoxide dismutase activities were significantly higher (P < 0.05) in GTRA, reducing lipid peroxidation when compared to the GCONT. Hematologic variables did not differ significantly between groups. Among the metabolic variables, only urea was higher in the GTRA group when compared to the GCON. Body weight and feed efficiency did not differ between groups (meaning the percentage of apparent digestibility of dry matter, crude protein, and acid detergent fiber (ADF) and neutral detergent fiber (NDF). There was a tendency (P = 0.09) for treatment effect and a treatment x day interaction (P = 0.05) for levels of short-chain fatty acids in rumen fluid, being lower in animals that consumed curcumin. There was a treatment vs. day interaction (P < 0.05) for the concentration of acetate in the rumen fluid (i.e., on day 45, had a reduction in acetate; on day 90, values were higher in the GTRA group when compared to the GCON). We conclude that there was no evidence in the results from this preliminary trial that Curcumin in the diet of dairy calves interfered with feed digestibility. Curcumin may have potential antioxidant, anti-inflammatory, and immune effects that may be desirable for the production system of dairy calves.

In vitro evaluation of Lactiplantibacillus plantarum HOKKAIDO strain, effective lactic acid bacteria for calf diarrhea

Calf diarrhea adversely affects growth and sometimes results in mortality, leading to severe economic losses to the cattle industry. Antibiotics are useful in the treatment against bacterial diarrhea, but not against viral, protozoan, and antibiotic-resistant bacterial diarrhea. Therefore, there are growing requirements for a novel control method for calf diarrhea. Probiotics have been considered promising candidates for preventive and supportive therapy for calf diarrhea for many years. A recent study has revealed that Lactiplantibacillus plantarum HOKKAIDO strain (Lp-HKD) reduces intestinal pathology and the severity of diarrhea in bovine rotavirus (BRV)-infected calves. Lp-HKD is known to enhance the function of human immune cells and expected to be used as probiotics for humans. Therefore, it is hypothesized that Lp-HKD modulates antiviral immune response in cattle and provide the clinical benefits in BRV-infected calves. However, the detailed mechanism of Lp-HKD-induced immunomodulation remains unknown. Thus, this study aimed to elucidate the immunomodulatory and antiviral effects of Lp-HKD in cattle. Cultivation assay of bovine peripheral blood mononuclear cells (PBMCs) showed that live and heat-killed Lp-HKD stimulates the production of interleukin-1β (IL-1β), IL-6, IL-10, and interferon-γ (IFN-γ) from PBMCs. Stimulation by heat-killed Lp-HKD yielded stronger cytokine production than stimulation by the live Lp-HKD. Additionally, CD14⁺ monocytes were identified as major producers of IL-1β, IL-6, and IL-10 under Lp-HKD stimulation; however, IFN-γ was mainly produced from immune cells other than CD14⁺ monocytes. Depletion of CD14⁺ monocytes from the PBMCs cultivation strongly decreased cytokine production induced by heat-killed Lp-HKD. The inhibition of toll-like receptor (TLR) 2/4 signaling decreased IL-1β and IL-6 production induced by live Lp-HKD and IL-1β, IL-6, and IFN-γ production induced by heat-killed Lp-HKD. Furthermore, live or heat-killed Lp-HKD also activated T cells and their production of IFN-γ and tumor necrosis factor-α. Then, culture supernatants of bovine PBMCs treated with heat-killed Lp-HKD demonstrated antiviral effects against BRV in vitro. In conclusion, this study demonstrated that Lp-HKD activates the functions of bovine immune cells via TLR2/4 signaling and exerts an antiviral effect against BRV through the induction of antiviral cytokines. Lp-HKD could be useful for the prevention and treatment of calf diarrhea through its immune activating effect.

Performance of Holstein calves receiving equal solids per day from high-solids milk and milk replacer blend once or twice daily combined with dry versus wet fine-particle starter diet

This study examined the effects of frequency of feeding high-solids milk and milk replacer (MMR) blend combined with dry matter (DM) content of starter feed on the performance of dairy calves. Forty-eight Holstein calves (40.2 ± 3.33 kg of body weight) were randomly assigned to 1 of 4 treatments in a completely randomized design. Based on a combination of 2 MMR feeding frequencies (once versus twice daily) and 2 starter DM levels (91.1 and 50% DM), 4 treatments were designed as (1) once daily + dry starter feed (OD), (2) once daily + wet starter feed (OW), (3) twice daily + dry starter feed (TD), and (4) twice daily + wet starter feed (TW). The amount of milk replacer powder added to whole milk was adjusted at each feeding frequency to ensure that calves received similar solids from the MMR blend via the twice-daily (total solids = 18.6%) or once-daily (total solids = 31.0%) programs. Starter intake in the preweaning period did not differ between treatments (average 0.39 kg of DM/d), but the postweaning starter intake was greater in calves fed the wet starter (OW and TW) than in those fed the dry starter (OD and TD). Calves receiving the high-solids MMR blend twice versus once daily grew faster before weaning, which was reflected by a greater weaning weight in the TD and TW groups (88.9 kg) than in the OD and OW groups (83.2 kg). The daily growth rate after weaning did not differ between treatments and averaged 1.15 kg/d. Gain-to-feed ratio during the preweaning period was greater in calves from TD and TW (mean 0.67) than in calves from the OD or OW groups (mean 0.58). Postweaning gain-to-feed ratio was not different among treatments and averaged 0.38. Days to first diarrhea and duration of diarrhea (4.66 ± 0.38), as well as days that animals were treated with antibiotics, remained unaffected with treatments. Although preweaning body weight gain was lower with once-daily milk feeding, calves were twice as heavy at weaning as at birth in both milk feeding programs regardless of starter moisture content, which may qualify the once-daily milk feeding program as a cost-effective management strategy in commercial calf-rearing operations. Feeding solutions with a high solids content (above 15%) may be associated with an increased risk of abomasal bloat and should be used with caution.

Biological Functions of Exopolysaccharides from Lactic Acid Bacteria and Their Potential Benefits for Humans and Farmed Animals

Lactic acid bacteria (LAB) synthesize exopolysaccharides (EPS), which are structurally diverse biopolymers with a broad range of technological properties and bioactivities. There is scientific evidence that these polymers have health-promoting properties. Most commercialized probiotic microorganisms for consumption by humans and farmed animals are LAB and some of them are EPS-producers indicating that some of their beneficial properties could be due to these polymers. Probiotic LAB are currently used to improve human health and for the prevention and treatment of specific pathologic conditions. They are also used in food-producing animal husbandry, mainly due to their abilities to promote growth and inhibit pathogens via different mechanisms, among which the production of EPS could be involved. Thus, the aim of this review is to discuss the current knowledge of the characteristics, usage and biological role of EPS from LAB, as well as their postbiotic action in humans and animals, and to predict the future contribution that they could have on the diet of food animals to improve productivity, animal health status and impact on public health.

Pre-weaning Ruminal Administration of Differentially-Enriched, Rumen-Derived Inocula Shaped Rumen Bacterial Communities and Co-occurrence Networks of Post-weaned Dairy Calves

Adult rumen fluid inoculations have been considered to facilitate the establishment of rumen microbiota of pre-weaned dairy calves. However, the sustained effects of the inoculations remain to be explored. In our previous study, 20 pre-weaned dairy calves had been dosed with four types of adult rumen inoculums [autoclaved rumen fluid, bacterial-enriched rumen fluid (BE), protozoal-enriched (PE), and BE + PE] weekly at 3 to 6 weeks of age. To verify the sustained effect of adult rumen inoculation, the rumen bacterial communities, fermentation characteristics, and animal performance measurements were measured after sacrifice from 20 post-weaned dairy bull calves (9 weeks of age). Ruminal pH tended to be lower in BE treated calves (n = 10). All PE treated calves had rumen ciliates (>104 cells per ml of rumen fluid). PE treated calves had greater VFA concentrations (P = 0.052), lower molar proportions of isobutyrate (P = 0.073), and butyrate (P = 0.019) compared to those of control calves. No treatment differences were found in all animal performance measurements. Both PE and BE inocula increased bacterial species richness, Faith's phylogenetic diversity, and Shannon's index in rumen liquid fractions. However, the relative proportion of those bacterial taxa possibly transferred from the donor's rumen was minor. Microbial network analysis showed different co-occurrence and mutually exclusive interactions between treatments of microbial inoculations. Collectively, adult rumen inoculations in pre-weaned dairy calves slightly altered the rumen bacteriome of post-weaned calves without changing fermentation and animal performance.

Direct evidence of the preventive effect of milk replacer-based probiotic feeding in calves against severe diarrhea

Diarrhea is a major cause of death in calves and this is linked directly to economic loss in the cattle industry. Fermented milk replacer (FMR) has been used widely in clinical settings for calf feeding to improve its health and growth. However, the protective efficacy of FMR on calf diarrhea remains unclear. In this study, we verified the preventive effects of FMR feeding on calf diarrhea using an experimental infection model of bovine rotavirus (BRV) in newborn calves and a field study in dairy farms with calf diarrhea. In addition, we evaluated the protective efficacy of lactic acid bacteria-supplemented milk replacer (LAB-MR) in an experimental infection model. In the experimental infection, calves fed FMR or high-concentrated LAB-MR had diarrhea, but the water content of feces was lower and more stable than that of calves fed normal milk replacer. The amount of milk intake also decreased temporarily, but recovered immediately in the FMR- and LAB-MR-fed calves. As compared with the control calves, FMR- or LAB-MR-fed calves showed less severe or reduced histopathological lesions of enteritis in the intestinal mucosa. In a field study using dairy calves, FMR feeding significantly reduced the incidence of enteritis, mortality from enteritis, duration of a series of treatment for enteritis, number of consultations, and cost of medical care for the disease. These results suggest that feeding milk replacer-based probiotics to calves reduces the severity of diarrhea and tissue damage to the intestinal tract caused by BRV infection and provides significant clinical benefits to the prevention and treatment of calf diarrhea.

Short communication: Performance of Holstein calves fed high-solid milk with or without nucleotide

Our initial hypothesis was that the exogenous supply of nucleotides to neonatal calves would improve the development and functionality of gastrointestinal tissue, thereby enhancing their capacity to efficiently digest and utilize the nutrients in high-solids milk. Twenty 3-d-old male Holstein calves (37.9 ± 2.24 kg of body weight) were distributed randomly to 1 of 2 treatments (1 calf per pen; 10 pens per treatment) without or with added nucleotides to their daily milk. Dry milk powder was added to pasteurized milk and offered as 4 L/d from d 3 to 15, 6 L/d from d 16 to 49 (at 0900 and 1600 h), and 2 L/d in morning feeding from d 50 to 55. High-solids milk (fat = 4.47%, protein = 4.64%, lactose = 8.13%, and total solids = 17.7%) was made through the addition of milk powder into whole milk and supplemented without or with 2 g/d of a commercially available nucleotide product, and then fed until weaning. Nucleotide supplementation had no effect on preweaning growth rate, but tended to increase postweaning daily weight gain (d 56-75). Unexpectedly, nucleotide supplementation tended to increase fecal score within the 10 d of calf life; thereafter (until weaning), no difference was detected in fecal consistency. Nucleotide supplementation tended to increase and increased pre- and postweaning dry matter intake, respectively. Efficiency of feed utilization (kilogram of weight gain per kilogram of dry matter intake) was not influenced with treatment. The net gain (d 1-70) of withers height and hip height tended to be greater in nucleotide-fed calves. Overall, addition of nucleotides to the high-solids milk had marginal effects on preweaning performance and tended to increase fecal scores (looser feces) in the initial phase of life; however, it increased starter feed intake and growth rate after weaning. A longer-feeding experiment is recommended to elucidate the potential effects of nucleotide supplementation in high-solids milk on calf performance.

Administration of Streptococcus bovis isolated from sheep rumen digesta on rumen function and physiology as evaluated in a rumen simulation technique system

BACKGROUND AND AIM

Little information about the stability and changes of sheep ruminal microbiota due to pathogen intervention in the rumen simulation technique (RUSITEC) is available. This study aimed to investigate the effect of administration of a novel isolated Streptococcus bovis strain on rumen microbiology and physiology. In addition, the isolation of pigment-producing Streptococcus lutetiensis is described.

MATERIALS AND METHODS

Microbial strains were isolated from sheep rumen digesta. An isolated strain of S. bovis was evaluated in the RUSITEC system fed with mixed cattle feed and compared with an in-house developed probiotic formulation (PF), PF 1, containing Bacillus amyloliquifaciens, Bacillus subtilis, and Propionibacterium freudenreichii. The parameters of volatile fatty acid, lactic acid, pH profiling, and the coliform anti-pathogenicity were evaluated to determine the effect of S. bovis on rumen function and physiology.

RESULTS

Administration of S. bovis reduced the coliform count by 31.20% from 7.2×1010 colony-forming units (CFU)/mLto 1.7×106 CFU/mL. Agar diffusion assays revealed the extracellular antimicrobial activity of S. bovis against coliforms; Escherichia coli and Salmonella enterica with 12 and 14 mm zones of inhibition, respectively. Simultaneously, an increase of 61.62% in the rumen yeast count was noted. The physiological changes resulted in a 5% reduction in acetic acid concentration from 431 to 405 mg/L.

CONCLUSION

The present research indicates that S. bovis is highly capable of altering rumen physiology and function on colonization and is a key transition microbe to be studied during rumen intervention studies. A decrease in the coliform count could be attributed to extracellular production of a bacteriocin-like substance, as illustrated through agar diffusion assays.

Microbial Inoculum Composition and Pre-weaned Dairy Calf Age Alter the Developing Rumen Microbial Environment

The objective of this experiment was to determine if dosing pre-weaned calves with enriched ruminal microbiota alters the rumen microbial environment and growth performance. Twenty Holstein bull calves were removed from their dam at birth, fed 3.8 L colostrum within 4 h after birth, and housed individually. Calves were fed pasteurized milk 3×/d from 0 to 7 weeks of age and offered a texturized calf starter ad libitum at 6 days of age. A randomized complete block design with repeated measures and a 2 × 2 factorial arrangement of treatments was used to evaluate responses. Treatments were administered by stomach intubation once per week from 3 to 6 weeks of age and included: 50 mL autoclaved rumen fluid (RF), 50 mL bacterial-enriched RF (BE), 50 mL protozoal-enriched RF (PE); or 50 mL of each BE and PE inoculum. A rumen content composite was collected from 4 rumen fistulated, lactating cows and used to create the inocula. BE inocula were microscopically confirmed to be free of ciliate protozoa before inoculation, while PE contained 2.9 ± 2.2 × 10⁵ protozoa/mL. RF was collected from the calves once per week before 50 mL of the inoculum was administered. Animal performance (e.g., weight gain and dry matter intake) was not altered by inocula type. All calves were microscopically free of rumen ciliates before inoculum administration and calves that did not receive PE remained ciliate-free. Ciliate protozoa were observed in RF from 6, 8, and 6 PE treated calves (n = 10) at weeks 4, 5, and 6, respectively. Ruminal NH₃ was lower in PE treated calves (3.3 vs. 6.8 ± 1.0 mM), while ruminal butyrate molar percent was greater in BE treated calves (10.8 vs. 8.3 ± 0.8). Rumen bacterial diversity measures did not differ by treatment at 3-6 weeks. Individual calf bacterial communities from treated calves became temporarily similar to the inocula at 4 weeks of age, but these communities diverged from the inocula at 5 weeks. This study provides new information about two types of rumen-derived inocula and insight into the challenges of directing the rumen microbial environment in the pre-weaned calf.

Effects and immune responses of probiotic treatment in ruminants

Gut microbial colonization and establishment are vital to ruminant health and production. This review article focuses on current knowledge and methods used to understand and manipulate the gut microbial community in ruminant animals, with a special focus on probiotics treatment. This review highlights the most promising of studies in this area, including gut microbial colonization and establishment, effect of gastrointestinal tract microbial community on host mucosal innate immune function, impact of feeding strategies on gut microbial community, current probiotic treatments in ruminants, methods to manipulate the gut microbiota and associated antimicrobial compounds, and models and cell lines used in understanding the host immune response to probiotic treatments. As a lot of work in this area was done in humans and mice, this review article also includes up-to-date knowledge from relevant studies in human and mouse models. This review is a useful resource for scientists working in the areas of ruminant nutrition and health, and to researchers investigating the microbial ecology and its relation to animal health.

Immunobiotics for the Bovine Host: Their Interaction with Intestinal Epithelial Cells and Their Effect on Antiviral Immunity

The scientific community has reported several cases of microbes that exhibit elevated rates of antibiotic resistance in different regions of the planet. Due to this emergence of antimicrobial resistant microorganisms, the use of antibiotics as promoters of livestock animals' growth is being banned in most countries around the world. One of the challenges of agricultural immunology therefore is to find alternatives by modulating the immune system of animals in drug-independent safe food production systems. In this regard, in an effort to supplant antibiotics from bovine feeds, several alternatives were proposed including the use of immunomodulatory probiotics (immunobiotics). The purpose of this review is to provide an update of the status of the modulation of intestinal antiviral innate immunity of the bovine host by immunobiotics, and the beneficial impact of immunobiotics on viral infections, focused on intestinal epithelial cells (IECs). The results of our group, which demonstrate the capacity of immunobiotic strains to beneficially modulate Toll-like receptor 3-triggered immune responses in bovine IECs and improve the resistance to viral infections, are highlighted. This review provides comprehensive information on the innate immune response of bovine IECs against virus, which can be further investigated for the development of strategies aimed to improve defenses in the bovine host.

Functional Resilience and Response to a Dietary Additive (Kefir) in Models of Foregut and Hindgut Microbial Fermentation In Vitro

Stability in gut ecosystems is an important area of study that impacts on the use of additives and is related with several pathologies. Kefir is a fermented milk drink made with a consortium of yeast and bacteria as a fermentation starter, of which the use as additive in companion and livestock animals has increased in the last few years. To investigate the effect of kefir milk on foregut and hindgut digestive systems, an in vitro approach was followed. Either rumen fluid or horse fecal contents were used as a microbial inoculate and the inclusion of kefir (fresh, autoclaved, or pasteurized) was tested. Gas production over 72 h of incubation was recorded and pH, volatile fatty acids (VFAs), lactate and ammonia concentration as well as lactic acid (LAB) and acetic acid bacteria, and yeast total numbers were also measured. Both direct and indirect (by subtracting their respective blanks) effects were analyzed and a multivariate analysis was performed to compare foregut and hindgut fermentation models. Addition of kefir boosted the fermentation by increasing molar concentration of VFAs and ammonia and shifting the Acetate to Propionate ratio in both models but heat processing techniques like pasteurization or autoclaving influenced the way the kefir is fermented and reacts with the present microbiota. In terms of comparison between both models, the foregut model seems to be less affected by the inclusion of Kefir than the hindgut model. In terms of variability in the response, the hindgut model appeared to be more variable than the foregut model in the way that it reacted indirectly to the addition of different types of kefir.