Effect of administration of bifidobacteria and lactic acid bacteria to newborn calves and piglets

An in-depth investigation of the microbiota and its virulence factors associated with severe udder cleft dermatitis lesions

Udder cleft dermatitis (UCD) is a skin condition affecting the anterior parts of the udder in dairy cattle. In the present study, we aimed to shed light on the microbiota in severe UCD lesions versus healthy udder skin by putting forward a taxonomic and functional profile based on a virulence factor analysis. Through shotgun metagenomic sequencing, we found a high proportion of bacteria in addition to a low abundance of archaea. A distinct clustering of healthy udder skin versus UCD lesion samples was shown by applying principal component analysis and (sparse) partial least squares analysis on the metagenomic data. Proteobacteria, Bacillota, and Actinomycetota were among the most abundant phyla in healthy udder skin samples. In UCD samples, Bacteroidota was the most abundant phylum. At genus level, Bifidobacterium spp. had the highest relative abundance in healthy skin samples, whereas Porphyromonas spp. and Corynebacterium spp. had the highest relative abundance in UCD samples. In the differential abundance analysis, Porphyromonas spp. and Bacteroides spp. were significantly differentially abundant in UCD samples, whereas Bifidobacterium spp., Staphylococcus sp. AntiMn-1, and Staphylococcus equorum were more commonly found in healthy samples. Moreover, the abundance of several treponeme phylotypes was significantly higher in lesion samples. The streptococcal cysteine protease speB was among the most abundant virulence factors present in severe UCD lesions, while a plethora of virulence factors such as the antitoxin relB were downregulated, possibly contributing to creating the ideal wound climate for the dysbiotic community. Network analysis showed healthy lesion samples had a large network ofpositive, correlations between the abundances of beneficial species such as Aerococcus urinaeequi and Bifidobacterium angulatum, indicating that the healthy skin microbiome forms an active protective bacterial network, which is disrupted in case of UCD. In UCD samples, a smaller microbial network mainly consisting of positive correlations between the abundances of Bacteroides fragilis and anaerobic Bacteroidota was exposed. Moreover, a high correlation between the taxonomic data and virulence factors was revealed, concurrently with 2 separate networks of microbes and virulence factors. One network, matching with the taxonomic findings in the healthy udder skin samples, showcased a community of harmless or beneficial bacteria, such as Bifidobacterium spp. and Butyrivibrio proteoclasticus, associated with hcnB, hcnC, relB, glyoxalase, and cupin 2. The other network, corresponding to UCD samples, consisted of pathogenic or facultative pathogenic and mainly anaerobic bacteria such as Treponema spp., Mycoplasmopsis spp., and bovine gammaherpesvirus 4, that correlated with virulence factors SpvB, fhaB, and haemagglutination activity domain-associated factor. Our results point toward a dysbiotic community with a notable decrease in diversity and evenness, with a loss of normal skin inhabitants and innocuous or useful species making way for predominantly anaerobic, facultative pathogens. The shift in the abundance of virulence factors such as fhaB and SpvB could play a role in the manifestation of a local micro-environment favorable to the microbiome associated with udder skin lesions. Lastly, the presence of specific networks between microbial species, and between microbes and virulence factors was shown.

Health-associated changes of the fecal microbiota in dairy heifer calves during the pre-weaning period

Introduction

Neonatal calf diarrhea is a multifactorial condition that occurs in early life when calves are particularly susceptible to enteric infection and dysbiosis of the gut microbiome. Good calf health is dependent on successful passive transfer of immunity from the dam through colostrum. There are limited studies on the developing gut microbiota from birth to weaning in calves.

Methodology

Therefore, the objective of this study was to examine the effect of immune status and diarrheal incidence on the development of the fecal microbiota in Jersey (n = 22) and Holstein (n = 29) heifer calves throughout the pre-weaning period. Calves were hand-fed a colostrum volume equivalent to 8.5% of their birthweight, from either the calf's dam (n = 28) or re-heated mixed colostrum (≤2 cows, ≤1d; n = 23) within 2 h of birth. All calves were clinically assessed using a modified Wisconsin-Madison calf health scoring system and rectal temperature at day (d) 0, d7, d21, or disease manifestation (DM) and weaning (d83). Weights were recorded at d0, d21, and d83. Calf blood samples were collected at d7 for the determination of calf serum IgG (sIgG). Fecal samples were obtained at d7, d21/DM [mean d22 (SE 0.70)], and at weaning for 16S rRNA amplicon sequencing of the fecal microbiota. Data were processed in R using DADA2; taxonomy was assigned using the SILVA database and further analyzed using Phyloseq and MaAsLin 2.

Results and discussion

Significant amplicon sequence variants (ASVs) and calf performance data underwent a Spearman rank-order correlation test. There was no effect (p > 0.05) of colostrum source or calf breed on serum total protein. An effect of calf breed (p < 0.05) was observed on sIgG concentrations such that Holstein calves had 6.49 (SE 2.99) mg/ml higher sIgG than Jersey calves. Colostrum source and calf breed had no effect (p > 0.05) on health status or the alpha diversity of the fecal microbiota. There was a relationship between health status and time interaction (p < 0.001), whereby alpha diversity increased with time; however, diarrheic calves had reduced microbial diversity at DM. No difference (p > 0.05) in beta diversity of the microbiota was detected at d7 or d83. At the genus level, 33 ASVs were associated (adj.p < 0.05) with health status over the pre-weaning period.

The Effects of Microbial Additive Supplementation on Growth Performance, Blood Metabolites, Fecal Microflora, and Carcass Characteristics of Growing-Finishing Pigs

This study aimed to assess the effects of microbial additives that produce antimicrobial and digestive enzymes on the growth performance, blood metabolites, fecal microflora, and carcass characteristics of growing-finishing pigs. A total of 180 growing-finishing pigs (Landrace × Yorkshire × Duroc; mixed sex; 14 weeks of age; 58.0 ± 1.00 kg) were then assigned to one of three groups with three repetitions (20 pigs) per treatment for 60 days of adaptation and 7 days of collection. Dietary treatments included 0, 0.5, and 1.0% microbial additives in the basal diet. For growth performance, no significant differences in the initial and final weights were observed among the dietary microbial additive treatments, except for the average daily feed intake, average daily gain, and feed efficiency. In terms of blood metabolites and fecal microflora, immunoglobulin G (IgG), blood urea nitrogen, blood glucose, and fecal lactic acid bacteria count increased linearly, and fecal E. coli counts decreased linearly with increasing levels of microbial additives but not growth hormones and Salmonella. Carcass quality grade was improved by the microbial additive. In addition, carcass characteristics were not influenced by dietary microbial additives. In conclusion, dietary supplementation with 1.0% microbial additive improved average daily gain, feed efficiency, IgG content, and fecal microflora in growing-finishing pigs.

A Comprehensive Review of Bovine Colostrum Components and Selected Aspects Regarding Their Impact on Neonatal Calf Physiology

Colostrum contains macro- and micronutrients necessary to meet the nutritional and energy requirements of the neonatal calf, bioactive components that intervene in several physiological aspects, and cells and microorganisms that modulate the calf's immune system and gut microbiome. Colostrum is sometimes mistaken as transition milk, which, although more nutritive than whole milk, has a distinct biochemical composition. Furthermore, most research about colostrum quality and colostrum management focuses on the transfer of maternal IgG to the newborn calf. The remaining components of colostrum and transition milk have not received the same attention, despite their importance to the newborn animal. In this narrative review, a large body of literature on the components of bovine colostrum was reviewed. The variability of these components was summarized, emphasizing specific components that warrant deeper exploration. In addition, the effects of each component present in colostrum and transition milk on several key physiological aspects of the newborn calf are discussed.

Effect of feeding dairy calves with milk fermented with selected probiotic strains on occurrence of diarrhoea, carriage of pathogenic and zoonotic microorganisms and growth performance

Calf-diarrhoea is a major health problem in dairy calves and a primary reason for use of antimicrobials. We aimed to investigate the effect of feeding milk fermented with a combination of four probiotic bacterial strains to young-calves on; occurrence of diarrhoea and associated-pathogens (bacteria, virus and parasites), shedding of Salmonella Dublin and Campylobacter, occurrence of virulence genes linked to Clostridium perfringens, Enterotoxigenic Escherichia coli and shiga-toxin producing E. coli (STEC), as well as growth performance. For this, 143 new-born calves from three Danish dairy-farms were allocated into Treatment- (fed the fermented milk for the first 8-weeks-of-life) and Control-groups (fed regular farm-milk). Diarrhoea was observed in 18.6 % (Farm 1), 22.4 % (Farm 2) and 15.7 % (Farm 3) of the total registrations mainly within the first 3-weeks-of-life. C. perfringens was the most frequently detected pathogen. The treatment did not affect the occurrence of virulence genes linked to STEC and C. perfringens and, overall, their detection levels were very low/undetected. The statistical model applied found no significant effect of the treatment on prevalence of early-diarrhoea (≤ 3 weeks), late-diarrhoea (>3 weeks), occurrence of C. perfringens and Cryptosporidium parvum or levels of Campylobacter spp. Limited detection of the other pathogens and associated virulence-genes under study, did not allow for assessment of the impact of the treatment on their occurrence. Notably, the feeding-approach showed a significant detrimental effect on daily-weight-gain. The inefficacy of the treatment may be associated with the complexity of influencing factors under field conditions including management practices.

Saccharomyces cerevisiae boulardii accelerates intestinal microbiota maturation and is correlated with increased secretory IgA production in neonatal dairy calves

Neonatal calves have a limited capacity to initiate immune responses due to a relatively immature adaptive immune system, which renders them susceptible to many on-farm diseases. At birth, the mucosal surfaces of the intestine are rapidly colonized by microbes in a process that promotes mucosal immunity and primes the development of the adaptive immune system. In a companion study, our group demonstrated that supplementation of a live yeast probiotic, Saccharomyces cerevisiae boulardii (SCB) CNCM I-1079, to calves from birth to 1 week of age stimulates secretory IgA (sIgA) production in the intestine. The objective of the study was to evaluate how SCB supplementation impacts the intestinal microbiota of one-week-old male calves, and how changes in the bacterial community in the intestine relate to the increase in secretory IgA. A total of 20 calves were randomly allocated to one of two treatments at birth: Control (CON, n = 10) fed at 5 g/d of carrier with no live yeast; and SCB (n = 10) fed at 5 g of live SCB per day (10 × 109 CFU/d). Our study revealed that supplementing calves with SCB from birth to 1 week of age had its most marked effects in the ileum, increasing species richness and phylogenetic diversity in addition to expediting the transition to a more interconnected bacterial community. Furthermore, LEfSe analysis revealed that there were several differentially abundant taxa between treatments and that SCB increased the relative abundance the family Eubacteriaceae, Corynebacteriaceae, Eggerthellaceae, Bacillaceae, and Ruminococcaceae. Furthermore, network analysis suggests that SCB promoted a more stable bacterial community and appears to reduce colonization with Shigella. Lastly, we observed that the probiotic-driven increase in microbial diversity was highly correlated with the enhanced secretory IgA capacity of the ileum, suggesting that the calf's gut mucosal immune system relies on the development of a stable and highly diverse microbial community to provide the necessary cues to train and promote its proper function. In summary, this data shows that supplementation of SCB promoted establishment of a diverse and interconnected microbiota, prevented colonization of Escherichia Shigella and indicates a possible role in stimulating humoral mucosal immunity.

Comparison of the Effects of Feeding Compound Probiotics and Antibiotics on Growth Performance, Gut Microbiota, and Small Intestine Morphology in Yellow-Feather Broilers

This study was devoted to the comparison of the probiotic effect of compound probiotics to antibiotics as a feed additive for chicken. Two hundred and seventy newly hatched yellow-feather broilers were randomly divided into three groups: the control group (Con), probiotics (Pb), and antibiotics group (Ab). The Pb group received compound probiotics (Bifidobacterium, Lactobacillus acidophilus, Streptococcus faecalis, and yeast) via drinking water for 24 days. The Ab group received antibiotics (zinc bacitracin and colistin sulfate) in their diet for 24 days. All broilers were slaughtered on day 42. Compared with the Con group, the body weight was significantly increased on days 13, 28, and 42 in the Pb group (p < 0.05), and markedly increased on day 28 in the Ab group (p < 0.05). Compared with the Ab group, the body weight of the broilers in the Pb group increased significantly on day 13 (p < 0.05). Compared to the Con and Pb groups, the antibiotics treatment reduced the feed intake (p < 0.05), but there was no significant difference in the feed conversion ratio between the Ab and Pb groups (p > 0.05). The feed conversion ratio of the broilers treated with antibiotics or probiotics significantly decreased compared to the Con group (p < 0.05). The depth of duodenum, jejunum, and ileum crypts in the Pb group decreased significantly compared to the Con and Ab group (p < 0.05). The ratio of the villi length to crypt depth of duodenum, jejunum, and ileum epithelium was significantly increased in the Pb group compared to the Con group (p < 0.05). The genera Bacteroides and Barnesiella were the most significantly enriched bacteria in the Ab and Pb groups, respectively (p < 0.05). The expression of the genes related to antibiotic resistance was significantly decreased in the Pb group compared to the Ab group (p < 0.05). Although both compound probiotics and antibiotics can improve growth performance, antibiotics increased the abundance of harmful bacteria and drug-resistant genes, while probiotics increased Barnesiella abundance, which is related to a decrease in the drug-resistant gene expression. Moreover, the probiotics treatment improved small intestinal morphology and fecal emissions, while antibiotics have no significant effect on these indicators, indicating a bright future for probiotics as an alternative to feed antibiotics in the yellow-feather broiler industry.

Specific pathway abundances in the neonatal calf faecal microbiome are associated with susceptibility to Cryptosporidium parvum infection: a metagenomic analysis

BACKGROUND

Cryptosporidium parvum is the main cause of calf scour worldwide. With limited therapeutic options and research compared to other Apicomplexa, it is important to understand the parasites' biology and interactions with the host and microbiome in order to develop novel strategies against this infection. The age-dependent nature of symptomatic cryptosporidiosis suggests a link to the undeveloped immune response, the immature intestinal epithelium, and its associated microbiota. This led us to hypothesise that specific features of the early life microbiome could predict calf susceptibility to C. parvum infection.

RESULTS

In this study, a single faecal swab sample was collected from each calf within the first week of life in a cohort of 346 animals. All 346 calves were subsequently monitored for clinical signs of cryptosporidiosis, and calves that developed diarrhoea were tested for Rotavirus, Coronavirus, E. coli F5 (K99) and C. parvum by lateral flow test (LFT). A retrospective case-control approach was taken whereby a subset of healthy calves (Control group; n = 33) and calves that went on to develop clinical signs of infectious diarrhoea and test positive for C. parvum infection via LFT (Cryptosporidium-positive group; n = 32) were selected from this cohort, five of which were excluded due to low DNA quality. A metagenomic analysis was conducted on the faecal microbiomes of the control group (n = 30) and the Cryptosporidium-positive group (n = 30) prior to infection, to determine features predictive of cryptosporidiosis. Taxonomic analysis showed no significant differences in alpha diversity, beta diversity, and taxa relative abundance between controls and Cryptosporidium-positive groups. Analysis of functional potential showed pathways related to isoprenoid precursor, haem and purine biosynthesis were significantly higher in abundance in calves that later tested positive for C. parvum (q ≤ 0.25). These pathways are either absent or streamlined in the C. parvum parasites. Though the de novo production of isoprenoid precursors, haem and purines are absent, C. parvum has been shown to encode enzymes that catalyse the downstream reactions of these pathway metabolites, indicating that C. parvum may scavenge those products from an external source.

CONCLUSIONS

The host has previously been put forward as the source of essential metabolites, but our study suggests that C. parvum may also be able to harness specific metabolic pathways of the microbiota in order to survive and replicate. This finding is important as components of these microbial pathways could be exploited as potential therapeutic targets for the prevention or mitigation of cryptosporidiosis in bovine neonates.

The Probiotic Bacillus subtilis MB40 Improves Immunity in a Porcine Model of Listeriosis

Probiotics for humans and direct-fed microbials for livestock are increasingly popular dietary ingredients for supporting immunity. The aim of this study was to determine the effects of dietary supplementation of Bacillus subtilis MB40 (MB40) on immunity in piglets challenged with the foodborne pathogen Listeria monocytogenes (LM). Three-week-old piglets (n = 32) were randomly assigned to four groups: (1) basal diet, (2) basal diet with LM challenge, (3) MB40-supplemented diet, and (4) MB40-supplemented diet with LM challenge. Experimental diets were provided throughout a 14-day (d) period. On d8, piglets in groups 2 and 4 were intraperitoneally inoculated with LM at 108 CFU/mL per piglet. Blood samples were collected at d1, d8, and d15 for biochemical and immune response profiling. Animals were euthanized and necropsied at d15 for liver and spleen bacterial counts and intestinal morphological analysis. At d15, LM challenge was associated with increased spleen weight (p = 0.017), greater circulating populations of neutrophils (p = 0.001) and monocytes (p = 0.008), and reduced ileal villus height to crypt depth ratio (p = 0.009), compared to non-challenged controls. MB40 supplementation reduced LM bacterial counts in the liver and spleen by 67% (p < 0.001) and 49% (p < 0.001), respectively, following the LM challenge, compared to the basal diet. MB40 supplementation was also associated with decreased circulating concentrations of monocytes (p = 0.007). Altogether, these data suggest that MB40 supplementation is a safe and well-tolerated approach to enhance immunity during systemic Listeria infection.

Whole-body microbiota of newborn calves and their response to prenatal vitamin and mineral supplementation

Early life microbial colonization and factors affecting colonization patterns are gaining interest due to recent developments suggesting that early life microbiome may play a role in Developmental Origins of Health and Disease. In cattle, limited information exists on the early microbial colonization of anatomical sites involved in bovine health beyond the gastrointestinal tract. Here, we investigated 1) the initial microbial colonization of seven different anatomical locations in newborn calves and 2) whether these early life microbial communities and 3) serum cytokine profiles are influenced by prenatal vitamin and mineral (VTM) supplementation. Samples were collected from the hoof, liver, lung, nasal cavity, eye, rumen (tissue and fluid), and vagina of beef calves that were born from dams that either received or did not receive VTM supplementation throughout gestation (n = 7/group). Calves were separated from dams immediately after birth and fed commercial colostrum and milk replacer until euthanasia at 30 h post-initial colostrum feeding. The microbiota of all samples was assessed using 16S rRNA gene sequencing and qPCR. Calf serum was subjected to multiplex quantification of 15 bovine cytokines and chemokines. Our results indicated that the hoof, eye, liver, lung, nasal cavity, and vagina of newborn calves were colonized by site-specific microbiota, whose community structure differed from the ruminal-associated communities (0.64 ≥ R² ≥ 0.12, p ≤ 0.003). The ruminal fluid microbial community was the only one that differed by treatment (p < 0.01). However, differences (p < 0.05) by treatment were detected in microbial richness (vagina); diversity (ruminal tissue, fluid, and eye); composition at the phylum and genus level (ruminal tissue, fluid, and vagina); and in total bacterial abundance (eye and vagina). From serum cytokines evaluated, concentration of chemokine IP-10 was greater (p = 0.02) in VTM calves compared to control calves. Overall, our results suggest that upon birth, the whole-body of newborn calves are colonized by relatively rich, diverse, and site-specific bacterial communities. Noticeable differences were observed in ruminal, vaginal, and ocular microbiota of newborn calves in response to prenatal VTM supplementation. These findings can derive future hypotheses regarding the initial microbial colonization of different body sites, and on maternal micronutrient consumption as a factor that may influence early life microbial colonization.

Modulating gastrointestinal microbiota to alleviate diarrhea in calves

The calf stage is a critical period for the development of heifers. Newborn calves have low gastrointestinal barrier function and immunity before weaning, making them highly susceptible to infection by various intestinal pathogens. Diarrhea in calves poses a significant threat to the health of young ruminants and may cause serious economic losses to livestock farms. Antibiotics are commonly used to treat diarrhea and promote calf growth, leading to bacterial resistance and increasing antibiotic residues in meat. Therefore, finding new technologies to improve the diarrhea of newborn calves is a challenge for livestock production and public health. The operation of the gut microbiota in the early stages after birth is crucial for optimizing immune function and body growth. Microbiota colonization of newborn animals is crucial for healthy development. Early intervention of the calf gastrointestinal microbiota, such as oral probiotics, fecal microbiota transplantation and rumen microbiota transplantation can effectively relieve calf diarrhea. This review focuses on the role and mechanisms of oral probiotics such as Lactobacillus, Bifidobacterium and Faecalibacterium in relieving calf diarrhea. The aim is to develop appropriate antibiotic alternatives to improve calf health in a sustainable and responsible manner, while addressing public health issues related to the use of antibiotics in livestock.

Colonization and development of the gut microbiome in calves

Colonization and development of the gut microbiome are crucial for the growth and health of calves. In this review, we summarized the colonization, beneficial nutrition, immune function of gut microbiota, function of the gut barrier, and the evolution of core microbiota in the gut of calves of different ages. Homeostasis of gut microbiome is beneficial for nutritional and immune system development of calves. Disruption of the gut microbiome leads to digestive diseases in calves, such as diarrhea and intestinal inflammation. Microbiota already exists in the gut of calf fetuses, and the colonization of microbiota continues to change dynamically under the influence of various factors, which include probiotics, diet, age, and genotype. Colonization depends on the interaction between the gut microbiota and the immune system of calves. The abundance and diversity of these commensal microbiota stabilize and play a critical role in the health of calves.

Comparative analysis of macroalgae supplementation on the rumen microbial community: Asparagopsis taxiformis inhibits major ruminal methanogenic, fibrolytic, and volatile fatty acid-producing microbes in vitro

Seaweeds have received a great deal of attention recently for their potential as methane-suppressing feed additives in ruminants. To date, Asparagopsis taxiformis has proven a potent enteric methane inhibitor, but it is a priority to identify local seaweed varieties that hold similar properties. It is essential that any methane inhibitor does not compromise the function of the rumen microbiome. In this study, we conducted an in vitro experiment using the RUSITEC system to evaluate the impact of three red seaweeds, A. taxiformis, Palmaria mollis, and Mazzaella japonica, on rumen prokaryotic communities. 16S rRNA sequencing showed that A. taxiformis had a profound effect on the microbiome, particularly on methanogens. Weighted Unifrac distances showed significant separation of A. taxiformis samples from the control and other seaweeds (p &lt; 0.05). Neither P. mollis nor M. japonica had a substantial effect on the microbiome (p &gt; 0.05). A. taxiformis reduced the abundance of all major archaeal species (p &lt; 0.05), leading to an almost total disappearance of the methanogens. Prominent fiber-degrading and volatile fatty acid (VFA)-producing bacteria including Fibrobacter and Ruminococcus were also inhibited by A. taxiformis (p &lt; 0.05), as were other genera involved in propionate production. The relative abundance of several other bacteria including Prevotella, Bifidobacterium, Succinivibrio, Ruminobacter, and unclassified Lachnospiraceae were increased by A. taxiformis suggesting that the rumen microbiome adapted to an initial perturbation. Our study provides baseline knowledge of microbial dynamics in response to seaweed feeding over an extended period and suggests that feeding A. taxiformis to cattle to reduce methane may directly, or indirectly, inhibit important fiber-degrading and VFA-producing bacteria.

Gut microbiota variation between climatic zones and due to migration strategy in passerine birds

Introduction

Decreasing biotic diversity with increasing latitude is an almost universal macroecological pattern documented for a broad range of taxa, however, there have been few studies focused on changes in gut microbiota (GM) across climatic zones.

Methods

Using 16S rRNA amplicon profiling, we analyzed GM variation between temperate (Czechia) and tropical (Cameroon) populations of 99 passerine bird species and assessed GM similarity of temperate species migrating to tropical regions with that of residents/short-distance migrants and tropical residents. Our study also considered the possible influence of diet on GM.

Results

We observed no consistent GM diversity differences between tropical and temperate species. In the tropics, GM composition varied substantially between dry and rainy seasons and only a few taxa exhibited consistent differential abundance between tropical and temperate zones, irrespective of migration behavior and seasonal GM changes. During the breeding season, trans-Saharan migrant GM diverged little from species not overwintering in the tropics and did not show higher similarity to tropical passerines than temperate residents/short-distance migrants. Interestingly, GM of two temperate-breeding trans-Saharan migrants sampled in the tropical zone matched that of tropical residents and converged with other temperate species during the breeding season. Diet had a slight effect on GM composition of tropical species, but no effect on GM of temperate hosts.

Discussion

Consequently, our results demonstrate extensive passerine GM plasticity, the dominant role of environmental factors in its composition and limited effect of diet.

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.

Probiotics media: significance, challenges, and future perspective - a mini review

The health benefits associated with probiotics have increased their application in pharmaceutical formulations and functional food development. High production of probiotic biomass requires a cost-effective production method and nutrient media optimization. The biomass production of probiotics can be enhanced by optimizing growth parameters such as substrate, pH, incubation time, etc. For economical industrial production of probiotic biomass, it is required to design a new medium with low cost. Wastes from the food industries are promising components for the development of the low-cost medium. Industrial wastes such as cheese whey and corn steep liquor are excellent examples of reliable sources of nitrogen for the biomass production of probiotic bacteria. The increased yield of biomass reduced the cost of production. This review focuses on the importance of probiotic media for biomass production and its challenges.

Graphical Abstract

Fecal microbiota dynamics and its relationship to diarrhea and health in dairy calves

BACKGROUND

Diarrhea is a major cause of morbidity and mortality in young calves, resulting in considerable economic loss for dairy farms. To determine if some gut microbes might have resistance to dysbiotic process with calf diarrhea by dictating the microbial co-occurrence patterns from birth to post-weaning, we examined the dynamic development of the gut microbiota and diarrhea status using two animal trials, with the first trial having 14 Holstein dairy calves whose fecal samples were collected 18 times over 78 d from birth to 15 d post-weaning and the second trial having 43 Holstein dairy calves whose fecal samples were collected daily from 8 to 18 days of age corresponding to the first diarrhea peak of trial 1.

RESULTS

Metataxonomic analysis of the fecal microbiota showed that the development of gut microbiota had three age periods with birth and weaning as the separatrices. Two diarrhea peaks were observed during the transition of the three age periods. Fusobacteriaceae was identified as a diarrhea-associated taxon both in the early stage and during weaning, and Clostridium_sensu_stricto_1 was another increased genus among diarrheic calves in the early stage. In the neonatal calves, Prevotella_2 (ASV4 and ASV26), Prevotella_9 (ASV43), and Alloprevotella (ASV14) were negatively associated with Clostridium_sensu_stricto_1 (ASV48), the keystone taxa of the diarrhea-phase module. During weaning, unclassified Muribaculaceae (ASV28 and ASV44), UBA1819 (ASV151), Barnesiella (ASV497), and Ruminococcaceae_UCG-005 (ASV254) were identified being associated with non-diarrheic status, and they aggregated in the non-diarrhea module of co-occurrence patterns wherein unclassified Muribaculaceae (ASV28) and Barnesiella (ASV497) had a direct negative relationship with the members of the diarrhea module.

CONCLUSIONS

Taken together, our results suggest that the dynamic successions of calf gut microbiota and the interactions among some bacteria could influence calf diarrhea, and some species of Prevotella might be the core microbiota in both neonatal and weaning calves, while species of Muribaculaceae might be the core microbiota in weaning calves for preventing calf diarrhea. Some ASVs affiliated with Prevotella_2 (ASV4 and ASV26), Prevotella_9 (ASV43), Alloprevotella (AVS14), unclassified Muribaculaceae (ASV28 and ASV44), UBA1819 (ASV151), Ruminococcaceae_UCG-005 (ASV254), and Barnesiella (ASV497) might be proper probiotics for preventing calf diarrhea whereas Clostridium_sensu_stricto_1 (ASV48) might be the biomarker for diarrhea risk in specific commercial farms.

Effects of a farm-specific fecal microbial transplant (FMT) product on clinical outcomes and fecal microbiome composition in preweaned dairy calves

Gastrointestinal disease (GI) is the most common illness in pre-weaned dairy calves. Therefore, effective strategies to manipulate the microbiome of dairy calves under commercial dairy operations are of great importance to improve animal health and reduce antimicrobial usage. The objective of this study was to develop a farm-specific FMT product and to investigate its effects on clinical outcomes and fecal microbial composition of dairy calves. The FMT product was derived from feces from healthy donors (5–24 days of age) raised in the same calf ranch facility as the FMT recipients. Healthy and diarrheic calves were randomly enrolled to a control (n = 115) or FMT (n = 112) treatment group (~36 g of processed fecal matter once daily for 3 days). Fecal samples were collected at enrollment and again 9 days later after the first FMT dose. Although the FMT product was rich in organisms typically known for their beneficial probiotic properties, the FMT therapy did not prevent or ameliorate GI disease in dairy calves. In fact, calves that received FMT were less likely to recover from GI disease, and more likely to die due to GI disease complications. Fecal microbial community analysis revealed an increase in the alpha-diversity in FMT calves; however, no major differences across treatment groups were observed in the beta-diversity analysis. Calves that received FMT had higher relative abundance of an uncultured organism of the genus Lactobacillus and Lactobacillus reuteri on day 10. Moreover, FMT calves had lower relative abundance of Clostridium nexile and Bacteroides vulgatus on day 10. Our results indicate the need to have an established protocol when developing FMT products, based on rigorous inclusion and exclusion criteria for the selection of FMT donors free of potential pathogens, no history of disease or antibiotic treatment.

Effects of Milk Replacer-Based Lactobacillus on Growth and Gut Development of Yaks' Calves: a Gut Microbiome and Metabolic Study

The gut microbiota and its metabolic activities are crucial for maintaining host homoeostasis and health, of which the role of probiotics has indeed been emphasized. The current study delves into the performance of probiotics as a beneficial managemental strategy, which further highlights their impact on growth performance, serologic investigation, gut microbiota, and metabolic profiling in yaks' calves. A field experiment was employed consisting of 2 by 3 factorial controls, including two development stages, namely, 21 and 42 days (about one and a half month), with three different feeding treatments. Results showed a positive impact of probiotic supplements on growth performance by approximately 3.16 kg (P < 0.01) compared with the blank control. Moreover, they had the potential to improve serum antioxidants and biochemical properties. We found that microorganisms that threaten health were enriched in the gut of the blank control with the depletion of beneficial bacteria, although all yaks were healthy. Additionally, the gut was colonized by a microbial succession that assembled into a more mature microbiome, driven by the probiotics strategy. The gut metabolic profiling was also changed significantly after the probiotic strategy, i.e., the concentrations of metabolites and the metabolic pattern, including enrichments in protein digestion and absorption, vitamin digestion and absorption, and biosynthesis of secondary metabolites. In summary, probiotics promoted gut microbiota/metabolites, developing precise interventions and achieving physiological benefits based on intestinal microecology. Hence, it is important to understand probiotic dietary changes to the gut microbiome, metabolome, and the host phenotype. IMPORTANCE The host microbiome is a composite of the trillion microorganisms colonizing host bodies. It can be impacted by various factors, including diet, environmental conditions, and physical activities. The yaks' calves have a pre-existing imbalance in the intestinal microbiota with an inadequate feeding strategy, resulting in poor growth performance, diarrhea, and other intestinal diseases. Hence, targeting gut microbiota might provide a new effective feeding strategy for enhancing performance and maintaining a healthy intestinal environment. Based on the current findings, milk replacer-based Lactobacillus feeding may improve growth performance and health in yaks' calves.

Comparative study of different liquid diets for dairy calves and the impact on performance and the bacterial community during diarrhea

The liquid diet composition can affect dairy calves' performance and diarrhea incidence. The effect of three liquid diets on performance, incidence of diarrhea, and microbial community during diarrhea occurrence in dairy calves were evaluated. At birth, 35 dairy calves (20 male and 15 female) were randomly assigned to one of three treatments-refrigerated whole milk (WM), acidified whole milk (AWM), and milk replacer (MR). Intake, fecal score, and rectal temperature were evaluated daily, and performance and blood parameters were evaluated weekly during the preweaning period. Fecal samples from diarrheic calves were collected, and one initial and one final sample for each episode were selected. The bacterial community was assessed by sequencing the V3-V4 region of the 16S rRNA gene on the Illumina MiSeq platform and analyzed using the DADA2 pipeline. Calves fed WM had higher body weight at weaning, average daily gain, body measurements, and concentration of blood metabolites. The AWM-fed calves had a lower rectal temperature and fever days. Moreover, the MR-fed calves had lower beta-hydroxybutyrate concentration and a higher incidence of diarrhea. The fecal bacterial community of diarrheic calves showed dissimilarity among the AWM and the other treatments. At the compositional level, we observed a higher abundance of Fusobacterium and Ruminococcus genera (AWM), Prevotella (WM), and Lactobacillus (MR). In the AWM and MR diarrheic calves' feces, we also observed some beneficial bacterial genera. The performance and incidence of diarrhea of dairy calves were influenced by the liquid diet consumed and the bacterial composition of diarrhea.

Effect of a 2-step probiotic program on digestive health and performance of Holstein heifer calves

Managing the composition of the bacterial communities in the digestive tract with the use of probiotics that enhance protective microflora could result in positive effects on health and performance of calves. The objective of this study was to evaluate a 2-step probiotic program (added to colostrum and milk) on the digestive health and growth of preweaning Holstein heifers. A randomized clinical trial was conducted from July to October 2020 in a calf rearing facility in Colorado. Calves were housed in pairs sharing the same treatment in 2 polyethylene hutches within a common area of 4.50 m². A total of 232 calves were enrolled at birth and randomly allocated into 2 treatment groups [control (CTR) = 116; treatment (PB) = 116] and followed until weaning (64 ± 3 d). Treatment consisted of 2 formulations of a multistrain bacterial-based probiotic added in colostrum (PBF1) and milk (PBF2). Treatment calves received 2 g of PBF1 added to each colostrum feeding, and 1 g of PBF2 added to the milk at the morning feeding 3 times per week up to weaning. Calf weight was collected at birth, at 30 d of age, and at weaning. Serum total protein was determined at age 3 ± 1 d and a health assessment was completed 3 times per week. Statistical analyses were performed using SAS, with calf considered the experimental unit clustered by housing pair. Cox proportional hazard analysis and time to event analysis were used to compare time to the first diarrhea event and time to recovery between treatment groups. The total number of diarrhea events and culling were assessed by Poisson regression and logistic regression analysis, respectively. Linear regression was performed to evaluate differences in average daily gain by treatment group. Overall, the mean (± standard error) temperature humidity index (THI) was 75 (± 0.44) units during the study period, which resulted in continuous exposure to heat stress in the day hours. No difference between treatment groups was observed in serum total protein. The overall incidence of diarrhea was 96.6% (CTR = 99%, PB = 95%); no differences were determined in the hazard of a first diarrhea episode or in the median time to the first diarrhea event (11 d in both groups). Similarly, no differences were found in the likelihood of recovery or in the median time to recovery from diarrhea (7 d in both groups). Likewise, treatment group was not associated with the number of diarrhea events, mean (± standard error, g/d) average daily gain from birth to weaning [CTR = 562.5 (13.9); PB = 570.8 (13.5)], or with the odds of culling. The most prevalent pathogen isolated from feces was Clostridium, which tended to be more frequent in CTR calves than PB calves. In conclusion, the probiotic program did not affect the incidence of enteric disease or the growth of preweaning heifer calves.

Phylogenetic diversity analysis of shotgun metagenomic reads describes gut microbiome development and treatment effects in the post-weaned pig

Intensive farming practices can increase exposure of animals to infectious agents against which antibiotics are used. Orally administered antibiotics are well known to cause dysbiosis. To counteract dysbiotic effects, numerous studies in the past two decades sought to understand whether probiotics are a valid tool to help re-establish a healthy gut microbial community after antibiotic treatment. Although dysbiotic effects of antibiotics are well investigated, little is known about the effects of intramuscular antibiotic treatment on the gut microbiome and a few studies attempted to study treatment effects using phylogenetic diversity analysis techniques. In this study we sought to determine the effects of two probiotic- and one intramuscularly administered antibiotic treatment on the developing gut microbiome of post-weaning piglets between their 3^rd and 9^th week of life. Shotgun metagenomic sequences from over 800 faecal time-series samples derived from 126 post-weaning piglets and 42 sows were analysed in a phylogenetic framework. Differences between individual hosts such as breed, litter, and age, were found to be important contributors to variation in the community composition. Host age was the dominant factor in shaping the gut microbiota of piglets after weaning. The post-weaning pig gut microbiome appeared to follow a highly structured developmental program with characteristic post-weaning changes that can distinguish hosts that were born as little as two days apart in the second month of life. Treatment effects of the antibiotic and probiotic treatments were found but were subtle and included a higher representation of Mollicutes associated with intramuscular antibiotic treatment, and an increase of Lactobacillus associated with probiotic treatment. The discovery of correlations between experimental factors and microbial community composition is more commonly addressed with OTU-based methods and rarely analysed via phylogenetic diversity measures. The latter method, although less intuitive than the former, suffers less from library size normalization biases, and it proved to be instrumental in this study for the discovery of correlations between microbiome composition and host-, and treatment factors.

Maternal Fecal Microbes Contribute to Shaping the Early Life Assembly of the Intestinal Microbiota of Co-inhabiting Yak and Cattle Calves

The Qinghai-Tibetan Plateau offers one of the most extreme environments for yaks (Bos grunniens). Although the genetic adaptability of yak and rumen metagenomes is increasingly understood, the relative contribution of host genetics and maternal symbiotic microbes throughout early intestinal microbial successions in yaks remains elusive. In this study, we assessed the intestinal microbiota succession of co-inhabiting yak and cattle (Bos taurus) calves at different weeks after birth as well as the modes of transmission of maternal symbiotic microbes (i.e., rumen fluid, feces, oral cavity, and breast skin) to their calves’ intestinal microbiota colonization. We found that the fecal microbiota of yak and cattle calves after birth was dominated by members of the families Ruminococcaceae, Bacteroidaceae, and Lachnospiraceae. The Source Tracker model revealed that maternal fecal microbes played an important role (the average contribution was about 80%) in the intestinal microbial colonization of yak and cattle calves at different weeks after birth. Unlike cattle calves, there was no significant difference in the fecal microbiota composition of yak calves between 5 and 9 weeks after birth (Wilcoxon test, P &gt; 0.05), indicating that yak may adapt to its natural extreme environment to stabilize its intestinal microbiota composition. Additionally, our results also find that the intestinal microbial composition of yak and cattle calves, with age, gradually tend to become similar, and the differences between species gradually decrease. The findings of this study are vital for developing strategies to manipulate the intestinal microbiota in grazing yaks and cattle for better growth and performance on the Qinghai-Tibetan Plateau.

Protective Effect of Bifidobacterium lactis JYBR-190 on Intestinal Mucosal Damage in Chicks Infected With Salmonella pullorum

Pullorum is one of the most serious diseases that endanger the chicken industry. With the advent of the era of anti-antibiotics in feed, the replacement of antibiotics by probiotics has become the focus and hotspot of related research. In this study, hematoxylin-eosin (H&E) staining, immunohistochemistry (IHC) and enzyme-linked immunosorbent assay (ELISA) were used to observe the structural changes of intestinal mucosa in chicks infected with Salmonella pullorum, and to analyze TNF-α, IL-10, IFN-γ, proliferating cell nuclear antigen (PCNA), and secreted immunoglobulin A (sIgA) levels. The results showed that the intestinal villus height, villus height to crypt depth ratio (V/C), and muscle layer thickness of duodenum, jejunum and cecum in the JYBR-190 group were significantly higher than those of the infection group and antibiotic group. Furthermore, the levels of PCNA, sIgA and IL-10 in JYBR-190 group were significantly increased, whereas the expression of TNF-α and IFN-γ was significantly decreased. Taken together, Bifidobacterium lactis JYBR-190 has a protective effect on intestinal mucosal damage in chicks infected with Salmonella pullorum.

Influence of microbial probiotics on ruminant health and nutrition: sources, mode of action and implications

Globally, ruminant production contributes immensely to the supply of the highest quality and quantity of proteins for human consumption, sustenance of livelihoods, and attainment of food security. Nevertheless, the phasing out of antibiotics in animal production has posed a myriad of challenges, including poor growth, performance and nutrient utilization, pathogen colonization, dysbiosis, and food safety issues in ruminants. Probiotics (direct-fed microbials), comprising live microbial strains that confer health and nutritional benefits to the host when administered in appropriate quantities, are emerging as a viable, safe, natural and sustainable alternative to antibiotics. Although the mechanisms of action exerted by probiotics on ruminants are not well elucidated, dietary probiotic dosage to ruminants enhances development and maturation, growth and performance, milk production and composition, nutrient digestibility, feed efficiency, pathogen reduction, and mitigation of gastrointestinal diseases. However, the beneficial response to probiotic supplementation in ruminants is not consistent, being dependent on the microbial strain selected, combination of strains, dose, time and frequency of supplementation, diet, animal breed, physiological stage, husbandry practice, and farm management. Nonetheless, several studies have recently reported beneficial effects of probiotics on ruminant performance, health and production. This review conclusively re-iterates the need for probiotics inclusion for the sustainability of ruminant production. Considering the role that ruminants play in food production and employment, global acceptance of sustainable ruminant production through supplementation with probiotics will undoubtedly ensure food security and food safety for the world. © 2021 Society of Chemical Industry.

Black soldier fly as feed ingredient for ruminants

This paper is a review of some experiments using black soldier fly (BSF) and its by-product to explore their nutritional value, production potential in Indonesia and its application in the ration of ruminants. Evaluation on the effect of milk replacer, creep feed containing BSF, BSF frass and the possibility to use lactic acid bacteria from BSF as probiotics are presented. Utilization of BSF larvae in milk replacer as skim and cream milk substitute showed that there were similarity on physiological, hematological status and performance of goat kids compared to those offered goat milk or commercial milk replacer. In addition, BSF larvae can be used to substitute soybean meal in the creep feed for post weaning goat kids without any differences in weight gain and blood profiles. However, utilization of BSF frass in the fattening goat ration resulted lower digestibility of dry matter and organic matter due to the chitin content in the frass. Black soldier fly larvae grown on chicken manure harbour lactic acid bacteria (LAB) which have potential as probiotics for ruminants. In general, BSF larvae has potential as ingredient for milk replacer, creep feed, fattening ration, and source of LAB for probiotics.

Fecal microbiome profiles of neonatal dairy calves with varying severities of gastrointestinal disease

Gastrointestinal disease (GI) is the most common illness in pre-weaned dairy calves. Studies have associated the fecal microbiome composition with health status, but it remains unclear how the microbiome changes across different levels of GI disease and breeds. Our objective was to associate the clinical symptoms of GI disease with the fecal microbiome. Fecal samples were collected from calves (n = 167) of different breeds (Holstein, Jersey, Jersey-cross and beef-cross) from 4-21 d of age. Daily clinical evaluations assessed health status. Calves with loose or watery feces were diagnosed with diarrhea and classified as bright-sick (BS) or depressed-sick (DS) according to behavior. Calves with normal or semiformed feces and no clinical illness were classified as healthy (H). One hundred and three fecal samples were obtained from consistently healthy calves and 64 samples were from calves with diarrhea (n = 39 BS; n = 25 DS). The V3-V4 region of 16S rRNA gene was sequenced and analyzed. Differences were identified by a linear-mixed effects model with a negative binomial error. DS and Jersey calves had a higher relative abundance of Streptococcus gallolyticus relative to H Holstein calves. In addition, DS calves had a lower relative abundance of Bifidobacterium longum and an enrichment of Escherichia coli. Species of the genus Lactobacillus, such as an unclassified Lactobacillus, Lactobacillus reuteri, and Lactobacillus salivarius were enriched in calves with GI disease. Moreover, we created a model to predict GI disease based on the fecal microbiome composition. The presence of Eggerthella lenta, Bifidobacterium longum, and Collinsella aerofaciens were associated with a healthy clinical outcome. Although lactobacilli are often associated with beneficial probiotic properties, the presence of E. coli and Lactobacillus species had the highest coefficients positively associated with GI disease prediction. Our results indicate that there are differences in the fecal microbiome of calves associated with GI disease severity and breed specificities.

Carryover effect of direct-fed microbial supplementation and early weaning on the growth performance and carcass characteristics of growing Najdi lambs

Growing Najdi lambs were randomly selected from lambs weaned at 30, 45, and 60 days old which were treated with 3 doses of direct-fed microbial (DFM) at 5, 10, and 15 days old to investigate the carryover effect of early weaning and DFM supplementation on their growth performance and carcass characteristics. Ten lambs from each group were transferred to individual pens for a feeding trial using the total mixed ration (Wafi). Lambs treated with DFM and weaned at 60 days old showed numerically higher body weight and average daily gains compared to other groups. Concerning the carcass and meat quality, there were significant differences between all groups in all carcass and tissue measurements, except for the back-fat and body wall thickness. In conclusion, treatment did not have any significant negative effect on body weight, feed intake, and conversion ratio compared with the control, but positively affected Zn and Cu absorption. DFM also played an important role in fat metabolism, which affects fat deposits in carcasses. The most important finding was that early weaning can be performed using DFM supplementation without any negative effect on the lambs’ performance during growth.

Dietary Probiotic Pediococcus acidilactici MA18/5M Improves the Growth, Feed Performance and Antioxidant Status of Penaeid Shrimp Litopenaeus stylirostris: A Growth-Ration-Size Approach

Simple Summary

Probiotics are increasingly documented to confer health and performance benefits across farmed animals. The study assessed the effect of dietary supplementation with the single-strain probiotic Pedicococcus acidilactici MA18/5M on the growth, nutritional indices, and metabolic status of the adult western blue shrimp, Litopenaeus stylirostris. The aim was to estimate its potential at optimizing the performance of the penaeid feed and shrimp farming industry. Supplementation with P. acidilactici MA18/5M improved the feed conversion efficiency and daily growth rate across fixed ration sizes; and decreased both the maintenance and optimal ration size for growth. This appeared linked to a better use of dietary carbohydrates as shown by a higher α-amylase activity, free-glucose and glycogen concentration in the digestive gland. Interestingly, P. acidilactici intake was also associated with a higher antioxidant status which may be linked to enhanced carbohydrates utilization. Using a fixed ration size approach under controlled laboratory conditions, the study documented a clear potential for P. acidilactici MA18/5M to enhance the growth, feed efficiency and metabolic health of adult penaeid shrimp during on-growing. These findings raise interesting prospects to optimize penaeid feed formulation and the performance of the shrimp-farming industry.

Abstract

Probiotics are increasingly documented to confer health and performance benefits across farmed animals. The aim of this study was to assess the effect of a constant daily intake of the single-strain probiotic Pedicococcus acidilactici MA18/5M (4 × 10⁸ CFU.day⁻¹.kg⁻¹ shrimp) fed over fixed, restricted ration sizes (1% to 6% biomass.day⁻¹) on the nutritional performance and metabolism of adult penaeid shrimp Litopenaeus stylirostris (initial body-weight, BWi = 10.9 ± 1.8 g). The probiotic significantly increased the relative daily growth rate (RGR) across all ration size s tested (Mean-RGR of 0.45 ± 0.08 and 0.61 ± 0.07% BWi.day⁻¹ for the control and probiotic groups, respectively) and decreased the maintenance ration (Rm) and the optimal ration (Ropt) by 18.6% and 11.3%, respectively. Accordingly, the probiotic group exhibited a significantly higher gross (K1) and net (K2) feed conversion efficiency with average improvement of 35% and 30%, respectively. Enhanced nutritional performances in shrimps that were fed the probiotic P. acidilactici was associated with, in particular, significantly higher α-amylase specific activity (+24.8 ± 5.5% across ration sizes) and a concentration of free-glucose and glycogen in the digestive gland at fixed ration sizes of 3% and below. This suggests that the probiotic effect might reside in a better use of dietary carbohydrates. Interestingly, P. acidilactici intake was also associated with a statistically enhanced total antioxidant status of the digestive gland and haemolymph (+24.4 ± 7.8% and +21.9 ± 8.5%, respectively; p < 0.05). As supported by knowledge in other species, enhanced carbohydrate utilization as a result of P. acidilactici intake may fuel the pentose-phosphate pathway, generating NADPH or directly enhancing OH-radicals scavenging by free glucose, in turn resulting in a decreased level of cellular oxidative stress. In conclusion, the growth-ration method documented a clear contribution of P. acidilactici MA18/5M on growth and feed efficiency of on-growing L. stylirostris that were fed fixed restricted rations under ideal laboratory conditions. The effect of the probiotic on α-amylase activity and carbohydrate metabolism and its link to the shrimp’s antioxidant status raises interesting prospects to optimize dietary formulations and helping to sustain the biological and economic efficiency of the penaeid shrimp-farming industry.

The Nasopharyngeal, Ruminal, and Vaginal Microbiota and the Core Taxa Shared across These Microbiomes in Virgin Yearling Heifers Exposed to Divergent In Utero Nutrition during Their First Trimester of Gestation and in Pregnant Beef Heifers in Response to Mineral Supplementation

In the present study, we evaluated whether the nasopharyngeal, ruminal, and vaginal microbiota would diverge (1) in virgin yearling beef heifers (9 months old) due to the maternal restricted gain during the first trimester of gestation; and (2) in pregnant beef heifers in response to the vitamin and mineral (VTM) supplementation during the first 6 months of pregnancy. As a secondary objective, using the microbiota data obtained from these two cohorts of beef heifers managed at the same location and sampled at the same time, we performed a holistic assessment of the microbial ecology residing within the respiratory, gastrointestinal, and reproductive tract of cattle. Our 16S rRNA gene sequencing results revealed that both α and β-diversity of the nasopharyngeal, ruminal and vaginal microbiota did not differ between virgin heifers raised from dams exposed to either a low gain (targeted average daily gain of 0.28 kg/d, n = 22) or a moderate gain treatment (0.79 kg/d, n = 23) during the first 84 days of gestation. Only in the vaginal microbiota were there relatively abundant genera that were affected by maternal rate of gain during early gestation. Whilst there was no significant difference in community structure and diversity in any of the three microbiota between pregnant heifers received no VTM (n = 15) and VTM supplemented (n = 17) diets, the VTM supplementation resulted in subtle compositional alterations in the nasopharyngeal and ruminal microbiota. Although the nasopharyngeal, ruminal, and vaginal microbiota were clearly distinct, a total of 41 OTUs, including methanogenic archaea, were identified as core taxa shared across the respiratory, gastrointestinal, and reproductive tracts of both virgin and pregnant heifers.

Gut microbiome colonization and development in neonatal ruminants: Strategies, prospects, and opportunities

Colonization and development of the gut microbiome is a crucial consideration for optimizing the health and performance of livestock animals. This is mainly attributed to the fact that dietary and management practices greatly influence the gut microbiota, subsequently leading to changes in nutrient utilization and immune response. A favorable microbiome can be implanted through dietary or management interventions of livestock animals, especially during early life. In this review, we explore all the possible factors (for example gestation, colostrum, and milk feeding, drinking water, starter feed, inoculation from healthy animals, prebiotics/probiotics, weaning time, essential oil and transgenesis), which can influence rumen microbiome colonization and development. We discuss the advantages and disadvantages of potential strategies used to manipulate gut development and microbial colonization to improve the production and health of newborn calves at an early age when they are most susceptible to enteric disease. Moreover, we provide insights into possible interventions and their potential effects on rumen development and microbiota establishment. Prospects of latest techniques like transgenesis and host genetics have also been discussed regarding their potential role in modulation of rumen microbiome and subsequent effects on gut development and performance in neonatal ruminants.

Local intestinal microbiota response and systemic effects of feeding black soldier fly larvae to replace soybean meal in growing pigs

Black soldier fly (Hermetia illucens; BSF) larvae as dietary protein source have the ability to deliver nutrients and could possess functional properties that positively support animal productivity and health. More knowledge, however, is needed to assess the impact of feeding a BSF based diet on gut and animal health. Sixteen post-weaned male pigs were randomly assigned to two groups and fed for three weeks with iso-caloric and iso-proteinaceous experimental diets prepared with either soybean meal (SBM) as reference protein source or with BSF as single source of dietary protein. At the end of the trial, the pigs were sacrificed to collect relevant digesta, gut tissue and blood samples to study changes induced by the dietary treatments using ~ omics based analyses. Inclusion of BSF in the diet supports the development of the intestinal microbiome that could positively influence intestinal health. By amine metabolite analysis, we identified two metabolites i.e. sarcosine and methionine sulfoxide, in plasma that serve as markers for the ingestion of insect based ingredients. BSF seems to possess functional properties indicated by the appearance of alpha-aminobutyric acid and taurine in blood plasma of pigs that are known to induce health beneficial effects.

Effect of in Ovo Inoculation of Bifidobacterium spp. on Growth Performance, Thyroid Activity, Ileum Histomorphometry, and Microbial Enumeration of Broilers

Early colonization by beneficial bacteria stimulates the function and development of the digestive tract, on which the performance and vitality of broilers rely. This experiment evaluated the effects of in ovo injection of bifidobacteria on the performance, thyroid activity, bacterial enumeration, and ileal histomorphometry of broiler chickens. A total of 360 fertile eggs were inoculated into the yolk sac, on day 17 of embryogenesis, and allocated to six experimental groups: negative control (not injected, G1), positive control (injected with sterilized distilled water, G2), and groups inoculated with 2 × 10⁸ CFU of Bifidobacterium bifidum, G3; B. animalis, G4; B. longum, G5; or B. infantis, G6. The results revealed an increase (P < 0.01) in body weight and weight gain in all treated groups increases of at least 5.38 and 8.27%, respectively, compared with the control. Feed consumption was not affected during all experimental periods, while the feed conversion ratio (FCR) was enhanced (P < 0.01) only for the overall experimental period (1-28 days of age). The G3 birds recorded the lowest FCR (1.38), while the highest was observed in G1 birds (1.57). Serum concentrations of thyroxin and triiodothyronine were elevated (P < 0.05) with probiotic inoculation. The antioxidant status and immune response of bifidobacteria injected birds were improved; the serum contents of superoxide dismutase and immunoglobulins Y, M, and A were increased (P < 0.05 and P < 0.01), while the malondialdehyde content was decreased (P < 0.01). Ileal architecture was improved in the bifidobacteria treated groups; the highest values of villus height and the villus height/crypt depth ratio were recorded in G3 (936.6 and 11.80) compared with those of G1 (537.1 and 6.93). Moreover, ileal lactic acid bacteria and Bifidobacterium spp. counts increased by at least 10.64 and 51.75%, while total coliform and bacterial counts reduced by at least 15.46 and 15.18%, respectively, compared with those of the control. In conclusion, all tested strains of bifidobacteria enhanced broiler growth performance, ileal function, and thyroid hormone metabolism without obvious differences among them.

Assessment of In Ovo Administration of Bifidobacterium bifidum and Bifidobacterium longum on Performance, Ileal Histomorphometry, Blood Hematological, and Biochemical Parameters of Broilers

Bifidobacterium is one of the most promising probiotics which was recently used as an alternative growth promoter in poultry. This trial was considered to evaluate the potential effects of in ovo administration of Bifidobacterium bifidum and Bifidobacterium longum on growth performance and biochemical parameters of broilers. Three hundred broiler breeder eggs were incubated and candled individually at day 17 of embryogenesis; then, eggs that had live embryos were randomly divided into six groups. The first and second groups were of intact (without injection) and vehicle-injected (sterile distilled water) control groups, respectively. Other groups were in ovo injected with 1 × 10⁹ and 1 × 10⁷ CFU B. bifidum, and 1 × 10⁹ and 1 × 10⁷ CFU B. longum, respectively. Hatchability was significantly (P < 0.001) affected by in ovo inoculation of bifidobacteria strains. Body weight gain and feed conversion ratio were significantly improved (P = 0.014 and 0.019, respectively) in all treatment groups. Protein fractions, aspartate aminotransferase, and alanine aminotransferase activities were not significantly altered by bifidobacteria strains in ovo injection. Regarding ileal histomorphometry parameters, a significant elevation in villus height and villus height/crypt depth ratio values were recorded while crypt depth was insignificantly affected by in ovo treatments. It could be concluded that the tested manual method of in-yolk sac injection at day 17 of incubation is more favorable in easier delivering of bifidobacteria strains which improve broiler growth performance and ileal development without any undesirable effects on blood indices and liver and renal functions.

Probiotic Lactobacillus johnsonii BS15 Promotes Growth Performance, Intestinal Immunity, and Gut Microbiota in Piglets

Numerous studies have investigated the beneficial effects of Lactobacillus johnsonii strain BS15 on mice and broilers. This study aimed to understand the growth-promoting effects of BS15 on piglets. We determined the effects of L. johnsonii BS15 and a commercial probiotic strain, Bacillus subtilis JS01. Seventy-two suckling piglets (1 ± 2-day-old) were divided into three groups and fed with diets supplemented with 1 × 10⁶ colony-forming units (cfu) BS15 per gram of feed (BS15 group); 1 × 10⁶ cfu JS01 per gram of feed (JS01 group); or de Man, Rogosa, and Sharpe liquid medium (control group) 35 days. Compared with JS01, BS15 significantly improved the daily weight gain and diarrhea index of the piglets. The BS15 group had higher fecal sIgA levels, whereas the JS01 group had high fecal sIgA levels only after 35 days of treatment. Additionally, BS15 altered T cell subsets in peripheral blood by significantly increasing the CD3⁺CD4⁺ T cell percentage and CD3⁺CD4⁺/CD3⁺CD8⁺ ratio and decreasing the CD3⁺CD8⁺ T cell percentage. Moreover, BS15 exerted better beneficial effects on fecal microbiota than JS01. Specifically, the BS15 group had markedly increased Clostridium, Peptococcus, and Lactobacillus populations on days 7 and 21 of treatment and reduced Escherichia coli populations on day 35 of treatment. These findings indicated that BS15 can be applied as a probiotic that promotes growth performance and controls diarrhea in piglets.

The Liquid Diet Composition Affects the Fecal Bacterial Community in Pre-weaning Dairy Calves

Feeding a liquid diet to the newborn calf has considerable implications for developing the intestinal microbiota, as its composition can shift the population to a highly adapted microbiota. The present work evaluated 15 Holstein calves individually housed and fed one of the three liquid diets: I – whole milk (n = 5), II – milk replacer (22.9% CP; 16.2% fat; diluted to 14% solids; n = 5) and III – acidified whole milk to pH 4.5 with formic acid (n = 5). All animals received 6 L of liquid diet, divided into two meals, being weaned at week 8 of life. Calves also had free access to water and starter concentrate. After weaning, all calves were grouped on pasture, fed with starter concentrate, and hay ad libitum. The fecal samples were collected at birth (0) and at weeks 1, 2, 4, 8, and 10 of life. The bacterial community was assessed the through sequencing of the V3-V4 region of the 16S rRNA gene on the Illumina MiSeq platform and analyzed using the DADA2 pipeline. Diversity indices were not affected by the liquid diets, but by age (P &lt; 0.001) with weeks 1 and 2 presenting lower diversity, evenness, and richness values. The bacterial community structure was affected by diet, age, and the interaction of these factors (P &lt; 0.01). Twenty-eight bacterial phyla were identified in the fecal samples, and the most predominant phyla were Firmicutes (42.35%), Bacteroidota (39.37%), and Proteobacteria (9.36%). The most prevalent genera were Bacteroides (10.71%), Lactobacillus (8.11%), Alloprevotella (6.20%). Over the weeks, different genera were predominant, with some showing significant differences among treatments. The different liquid diets altered the fecal bacterial community during the pre-weaning period. However, differences in the initial colonization due to different liquid diets are alleviated after weaning, when animals share a common environment and solid diet composition.

Lactobacillus plantarum GB LP-1 as a direct-fed microbial for neonatal calves

Direct-fed microbial feed additives with potential to enhance growth performance, gut health, and immunity have gained considerable popularity in neonatal calf production. Lactobacillus plantarum GB LP-1 (LP) produced by a proprietary fermentation process could be a viable direct-fed microbial feed for neonatal calves. The hypothesis was that feeding LP may ease transitioning from milk replacer (MR) to calf starter (CS) by improving gut health and appetite, while minimizing health challenges from pathogens and stress to improve growth performance. The experimental objective was to evaluate LP in an MR feeding program at 3 inclusion rates. Fifty-one 2- to 5-d-old Holstein bull calves were randomly assigned to 1 of 3 treatments using a randomized complete block design. Treatments were (1) Control (LP0): LP fed at 0 g/d; (2) LP4: LP fed at 4 g/d; and (3) LP8: LP fed at 8 g/d. Calves were fed MR at 0.57 kg/d for 14 d via bucket, which was increased to 0.85 kg/d until 35 d, and were then fed once daily at 0.425 kg/d with weaning after d 42 of the 56-d experiment. Calves were fed at 0630 and 1800 h in equal allotments, with access at all times to free-choice water and a pelleted CS with 25.5% crude protein. Calves demonstrated a linear growth response to increasing LP inclusion rate: calves fed LP8 gained more body weight (33.0, 36.9, and 37.7 kg for LP0, LP4, and LP8, respectively) than calves fed LP0, with calves fed LP4 being intermediate and similar. The 0-to-42-d (MR feeding phase) average daily gain (ADG; 562.9, 595.9, and 655.7 g/d) and 0-to-56-d ADG (588.6, 658.4, and 673.0 g/d) demonstrated linear responses, with calves fed LP8 having greater ADG than calves fed LP0, and calves fed LP4 being intermediate and similar. Total CS intake was similar among calves fed all treatments (66.3, 69.0, and 72.5 kg/56 d), which resulted in a quadratic response in feed efficiency (0.50, 0.53, and 0.52 kg of gain/kg of dry matter) for calves fed LP4 compared with calves fed LP0, with calves fed LP8 being intermediate and similar. Fecal scores improved linearly with increasing LP inclusion rate. These data demonstrate that feeding Lactobacillus plantarum GB LP-1 to neonatal calves improves gut health to increase growth performance at 4 and 8 g/d, while feed efficiency was greatest at 4 g/d.

Functional amino acid supplementation, regardless of dietary protein content, improves growth performance and immune status of weaned pigs challenged with Salmonella Typhimurium

High dietary protein may increase susceptibility of weaned pigs to enteric pathogens. Dietary supplementation with functional amino acids (FAA) may improve growth performance of pigs during disease challenge. The objective of this study was to evaluate the interactive effects of dietary protein content and FAA supplementation above requirements for growth on performance and immune response of weaned pigs challenged with Salmonella. Sixty-four mixed-sex weanling pigs (13.9 ± 0.82 kg) were randomly assigned to dietary treatments in a 2 × 2 factorial arrangement with low (LP) or high protein (HP) content and basal (AA-) or FAA profile (AA+; Thr, Met, and Trp at 120% of requirements) as factors. After a 7-d adaptation period, pigs were inoculated with either a sterile saline solution (CT) or saline solution containing Salmonella Typhimurium (ST; 3.3 × 109 CFU/mL). Growth performance, body temperature, fecal score, acute-phase proteins, oxidant/antioxidant balance, ST shedding score in feces and intestinal colonization, fecal and digesta myeloperoxidase (MPO), and plasma urea nitrogen (PUN) were measured pre- and postinoculation. There were no dietary effects on any measures pre-inoculation or post-CT inoculation (P > 0.05). Inoculation with ST increased body temperature and fecal score (P < 0.05), serum haptoglobin, plasma superoxide dismutase (SOD), malondialdehyde (MDA), PUN, and fecal MPO, and decreased serum albumin and plasma reduced glutathione (GSH):oxidized glutathione (GSSG) compared with CT pigs (P < 0.05). ST-inoculation reduced average daily gain (ADG) and feed intake (ADFI) vs. CT pigs (P < 0.05) but was increased by AA+ vs. AA- in ST pigs (P < 0.05). Serum albumin and GSH:GSSG were increased while haptoglobin and SOD were decreased in ST-inoculated pigs fed AA+ vs. AA- (P < 0.05). PUN was higher in HP vs. LP-fed pigs postinoculation (P < 0.05). Fecal ST score was increased in ST-inoculated pigs on days 1 and 2 postinoculation and declined by day 6 (P < 0.05) in all pigs while the overall score was reduced in AA+ vs. AA- pigs (P < 0.05). Cecal digesta ST score was higher in HP vs. LP-fed pigs and were lower in AA+ compared with AA- fed pigs in the colon (P < 0.05). Fecal and digesta MPO were reduced in ST pigs fed AA+ vs. AA- (P < 0.05). These results demonstrate a positive effect of FAA supplementation, with minimal effects of dietary protein, on performance and immune status in weaned pigs challenged with Salmonella.

Dynamic progression of the calf's microbiome and its influence on host health

The first year of a calf's life is a critical phase as its digestive system and immunity are underdeveloped. A high level of stress caused by separation from mothers, transportation, antibiotic treatments, dietary shifts, and weaning can have long-lasting health effects, which can reduce future production parameters, such as milk yield and reproduction, or even increase the mortality of calves. The early succession of microbes throughout the gastrointestinal tract of neonatal calves follows a sequential pattern of colonisation and is greatly influenced by their physiological state, age, diet, and environmental factors; this leads to the establishment of region- and site-specific microbial communities. This review summarises the current information on the various potential factors that may affect the early life microbial colonisation pattern in the gastrointestinal tract of calves. The possible role of host-microbe interactions in the development and maturation of host gut, immune system, and health are described. Additionally, the possibility of improving the health of calves through gut microbiome modulation and using antimicrobial alternatives is discussed. Finally, the trends, challenges, and limitations of the current research are summarised and prospective directions for future studies are highlighted.

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.

Rumen Microbiome Composition Is Altered in Sheep Divergent in Feed Efficiency

Rumen microbiome composition and functionality is linked to animal feed efficiency, particularly for bovine ruminants. To investigate this in sheep, we compared rumen bacterial and archaeal populations (and predicted metabolic processes) of sheep divergent for the feed efficiency trait feed conversion ratio (FCR). In our study 50 Texel cross Scottish Blackface (TXSB) ram lambs were selected from an original cohort of 200 lambs. From these, 26 were further selected for experimentation based on their extreme FCR (High Feed Efficiency, HFE = 13; Low Feed Efficiency, LFE = 13). Animals were fed a 95% concentrate diet ad libitum over 36 days. 16S rRNA amplicon sequencing was used to investigate the rumen bacterial and archaeal communities in the liquid and solid rumen fractions of sheep divergent for FCR. Weighted UniFrac distances separated HFE and LFE archaea communities from the liquid rumen fraction (Permanova, P < 0.05), with greater variation observed for the LFE cohort (Permdisp, P < 0.05). LFE animals exhibited greater Shannon and Simpson diversity indices, which was significant for the liquid rumen fraction (P < 0.05). Methanobrevibacter olleyae (in liquid and solid fractions) and Methanobrevibacter millerae (liquid fraction) were differentially abundant, and increased in the LFE cohort (P.adj < 0.05), while Methanobrevibacter wolinii (liquid fraction) was increased in the HFE cohort (P.adj < 0.05). This suggests that methanogenic archaea may be responsible for a potential loss of energy for the LFE cohort. Bacterial community composition (Permanova, P > 0.1) and diversity (P > 0.1) was not affected by the FCR phenotype. Only the genus Prevotella 1 was differentially abundant between HFE and LFE cohorts. Although no major compositional shifts of bacterial populations were identified amongst the feed efficient cohorts (FDR > 0.05), correlation analysis identified putative drivers of feed efficiency with Ruminococcaceae UCG-014 (liquid, rho = −0.53; solid, rho = −0.56) and Olsenella (solid, rho = −0.40) exhibiting significant negative association with FCR (P < 0.05). Bifidobacterium and Megasphaera showed significant positive correlations with ADG. Major cellulolytic bacteria Fibrobacter (liquid, rho = 0.43) and Ruminococcus 1 (liquid, rho = 0.41; solid, rho = 41) correlated positively with FCR (P < 0.05). Our study provides evidence that feed efficiency in sheep is likely influenced by compositional changes to the archaeal community, and abundance changes of specific bacteria, rather than major overall shifts within the rumen microbiome.

Effects of dietary feed supplementation of heat-treated Lactobacillus sakei HS-1 on the health status, blood parameters, and fecal microbes of Japanese Black calves

This study investigated the effect of heat-killed Lactobacillus sakei HS-1 (HK-LS HS-1) on the health and fecal bacteriological change of suckling Japanese Black calves as a supplement in milk replacers. Twelve calves were separated from dams to calf-hatch after calving for milk replacers feeding. They were randomly assigned to an HK-LS HS-1 supplement or a control without HK-LS HS-1 group in milk replacers. HK-LS HS-1 was administered from separation day to 3 weeks. Blood and fecal samples were examined. Two calves with a haptoglobin concentration of >500 µg/ml on day 0 were excluded from the experiment, and 10 calves were finally included. Glucose and vitamin A levels on day 7 were significantly higher (P<0.05) in the supplement group than in the control group. No significant differences were observed in haptoglobin or serum amyloid A between the groups. The number of Escherichia coli in feces was lower in the control group than in the supplement group on day 21 (P=0.06). No difference was observed in the number of bifidobacteria, but that of lactic acid bacteria was significantly higher (P<0.05) in the supplement group on day 21. The number of medications administered was significantly lower (P<0.05) in the supplement group (5.2 ± 3.9) than in the control group (10.6 ± 5.9) during the experimental period. The results indicated that HK-LS HS-1 is potentially beneficial for improving intestinal microbes and reducing the number of medical treatments.

Dietary Supplementation with Sugar Beet Fructooligosaccharides and Garlic Residues Promotes Growth of Beneficial Bacteria and Increases Weight Gain in Neonatal Lambs

The proper development of the early gastrointestinal tract (GIT) microbiota is critical for newborn ruminants. This microbiota is susceptible to modification by diverse external factors (such as diet) that can lead to long-lasting results when occurring in young ruminants. Dietary supplementation with prebiotics, ingredients nondigestible and nonabsorbable by the host that stimulate the growth of beneficial GIT bacteria, has been applied worldwide as a potential approach in order to improve ruminant health and production yields. However, how prebiotics affect the GIT microbiota during ruminants’ early life is still poorly understood. We investigated the effect of milk supplementation with a combination of two well-known prebiotics, fructooligosaccharides (FOS) from sugar beet and garlic residues (all together named as “additive”), exerted on preweaned lamb growth and the composition of their fecal microbiota, by using 16S rRNA gene amplicon high-throughput sequencing. The results showed a significant increase in the mean daily weight gain of lambs fed with the additive. Lamb fecal microbiota was also influenced by the additive intake, as additive-diet lambs showed lower bacterial diversity and were significantly more abundant in Bifidobacterium, Enterococcus, Lactobacillus and Veillonella. These bacteria have been previously reported to confer beneficial properties to the ruminant, including promotion of growth and health status, and our results showed that they were strongly linked to the additive intake and the increased weight gain of lambs. This study points out the combination of FOS from sugar beet and garlic residues as a potential prebiotic to be used in young ruminants’ nutrition in order to improve production yields.

The Composition and Function of Pigeon Milk Microbiota Transmitted From Parent Pigeons to Squabs

Mammalian neonates obtain antibodies, nutrients, and microbiota from breast milk that help them resist the complex growth environment. Similar to mammals' lactation behavior for their offspring, parent pigeons regurgitate pigeon milk (PM) from their crops to feed the squabs. Whether pigeon milk is as valuable as mammalian milk is not clear, especially in terms of microbiota. This study adopted 16S rRNA gene sequencing to investigate the microbial composition and function in pigeon milk. We found abundant microbiota in pigeon milk. The dominant genera in parent pigeons' milk were Lactobacillus, Enterococcus, Veillonella, and Bifidobacterium. An analysis of squab milk (SM) showed that Lactobacillus also accounted for a considerable proportion, followed by Bifidobacterium. Most of the squab milk microbial genera were also detected in parent pigeons. Microbial functional analysis showed that the squab milk microbes were more involved in the pathways of carbohydrate metabolism, amino acid metabolism, and energy metabolism. These findings indicated that microbiota play an important role in squabs and can be transmitted from parent pigeons to squabs by pigeon milk. The presence of plentiful probiotics in squabs also suggests that adding probiotics in artificial pigeon milk may promote the growth and development of squabs and improve the production performance of pigeons.

Relationship between the Quality of Colostrum and the Formation of Microflora in the Digestive Tract of Calves

Simple Summary

Colostrum is a source of antibodies and immunostimulatory components; however, it is also a factor that guarantees the rapid multiplication of microorganisms in the digestive system, which significantly affects the proper functioning of the calf’s body. The aim of the study was to determine the relationship between the quality of colostrum and the formation of intestinal bacterial microflora in calves from birth to day 7. The study showed a significant influence of colostrum quality class on the formation of the intestinal microbiome and the daily weight gains of calves. The quality of the colostrum influences the intestinal microbiome. The higher the concentration of bioactive components, the more probiotic bacterial strains can develop.

Abstract

The aim of the study was to determine the relationship between the quality of colostrum and the formation of intestinal bacterial microflora in calves from birth to day 7. Seventy-five multiparous Polish Holstein–Friesian cows were selected. Colostrum samples were collected individually up to two hours after calving. The analysis was carried out on 75 calves; which were divided into three groups based on the colostrum quality class of the first milking. Faecal samples were collected rectally from each calf on its seventh day of life. Calves were weighed twice; on days 0 and 7 of life. It has been shown that with a higher concentration of colostrum protein fraction, primarily immunoglobulins, the colonisation of anaerobic bacteria occurs faster. Colostrum with a density >1.070 g/cm³ promoted the significant development of Lactobacilli and Bifidobacterium spp. which at the same time contributed to the reduction of unfavourable microflora, such as Coliforms or Enterococci. Regardless of the initial body weight, daily weight gains were highest for calves fed with colostrum with a density >1.070 g/cm³. The study showed a significant influence of colostrum quality class on the formation of the intestinal microflora and the daily weight gains of calves.

Changes in the host transcriptome and microbial metatranscriptome of the ileum of dairy calves subjected to artificial dosing of exogenous rumen contents

Development of a properly functioning gastrointestinal tract (GIT) at an early age is critical for the wellbeing and lifetime productivity of dairy cattle. The role of early microbial colonization on GIT development in neonatal cattle and the associated molecular changes remain largely unknown, particularly for the small intestine. In this study, we performed artificial dosing of exogenous rumen fluid during the early life of the calf, starting at birth through the weaning transition at 8 wk. Six calves were included in this study. At 8 wk of age, tissue from the ileum was collected and subjected to host transcriptome and microbial metatranscriptome analysis using RNA sequencing. A total of 333 genes showed significant differential expression (DE) (fold-change ≥2; adjusted P < 0.1, mean read-count ≥10) between the treated and control calves. Gene ontology analysis indicated that these DE genes are predominantly associated with processes related to the host immune response (P < 0.0001). Association analysis between the host gene expression and the microbial genus abundance identified 57 genes as having significant correlation with the ileum microbial genera (P < 0.0001). Of these, three genes showed significant association with six microbial genera: lysozyme 2 (LYZ2), fatty acid binding protein 5 (FABP5), and fucosyltransferase (FUT1). Specifically, the profound increase in expression of LYZ2 in treated calves suggests the initiation of antibacterial activity and innate response from the host. Despite the limitation of a relatively small sample size, this study sheds light on the potential impact of early introduction of microbes on the small intestine of calves.