Review: Exogenous butyrate: implications for the functional development of ruminal epithelium and calf performance

Postnatal Growth and Development of the Rumen: Integrating Physiological and Molecular Insights

The rumen plays an essential role in the physiology and production of agriculturally important ruminants such as cattle. Functions of the rumen include fermentation, absorption, metabolism, and protection. Cattle are, however, not born with a functional rumen, and the rumen undergoes considerable changes in size, histology, physiology, and transcriptome from birth to adulthood. In this review, we discuss these changes in detail, the factors that affect these changes, and the potential molecular and cellular mechanisms that mediate these changes. The introduction of solid feed to the rumen is essential for rumen growth and functional development in post-weaning calves. Increasing evidence suggests that solid feed stimulates rumen growth and functional development through butyric acid and other volatile fatty acids (VFAs) produced by microbial fermentation of feed in the rumen and that VFAs stimulate rumen growth and functional development through hormones such as insulin and insulin-like growth factor I (IGF-I) or through direct actions on energy production, chromatin modification, and gene expression. Given the role of the rumen in ruminant physiology and performance, it is important to further study the cellular, molecular, genomic, and epigenomic mechanisms that control rumen growth and development in postnatal ruminants. A better understanding of these mechanisms could lead to the development of novel strategies to enhance the growth and development of the rumen and thereby the productivity and health of cattle and other agriculturally important ruminants.

Exploring the Role of G Protein Expression in Sodium Butyrate-Enhanced Pancreas Development of Dairy Calves: A Proteomic Perspective

The present study evaluated the effects of sodium butyrate (SB) supplementation on exocrine and endocrine pancreatic development in dairy calves. Fourteen male Holstein calves were alimented with either milk or milk supplemented with SB for 70 days. Pancreases were collected for analysis including staining, immunofluorescence, electron microscopy, qRT-PCR, Western blotting, and proteomics. Results indicated increased development in the SB group with increases in organ size, protein levels, and cell growth. There were also exocrine enhancements manifested as higher enzyme activities and gene expressions along with larger zymogen granules. Endocrine benefits included elevated gene expression, more insulin secretion, and larger islets, indicating a rise in β-cell proliferation. Proteomics and pathway analyses pinpointed the G protein subunit alpha-15 as a pivotal factor in pancreatic and insulin secretion pathways. Overall, SB supplementation enhances pancreatic development by promoting its exocrine and endocrine functions through G protein regulation in dairy calves.

Butyric acid and prospects for creation of new medicines based on its derivatives: a literature review

The widespread use of antimicrobials causes antibiotic resistance in bacteria. The use of butyric acid and its derivatives is an alternative tactic. This review summarizes the literature on the role of butyric acid in the body and provides further prospects for the clinical use of its derivatives and delivery methods to the animal body. Thus far, there is evidence confirming the vital role of butyric acid in the body and the effectiveness of its derivatives when used as animal medicines and growth stimulants. Butyric acid salts stimulate immunomodulatory activity by reducing microbial colonization of the intestine and suppressing inflammation. Extraintestinal effects occur against the background of hemoglobinopathy, hypercholesterolemia, insulin resistance, and cerebral ischemia. Butyric acid derivatives inhibit histone deacetylase. Aberrant histone deacetylase activity is associated with the development of certain types of cancer in humans. Feed additives containing butyric acid salts or tributyrin are used widely in animal husbandry. They improve the functional status of the intestine and accelerate animal growth and development. On the other hand, high concentrations of butyric acid stimulate the apoptosis of epithelial cells and disrupt the intestinal barrier function. This review highlights the biological activity and the mechanism of action of butyric acid, its salts, and esters, revealing their role in the treatment of various animal and human diseases. This paper also discussed the possibility of using butyric acid and its derivatives as surface modifiers of enterosorbents to obtain new drugs with bifunctional action.

Campos M. Effects of Supplementing Milk Replacer with Sodium Butyrate on Dairy Calves

Diarrhea and respiratory diseases pose significant challenges in the rearing of pre-weaned calves, motivating the investigation of tools to improve gastrointestinal tract development, health, and overall performance in young calves. Consequently, the primary objective of this study was to assess the effectiveness of an additive incorporated into milk replacer to promote the development and health of the animals. Forty-six dairy calves were randomly assigned into two treatments: control (CON, n = 23; with 15 females and 8 males), and sodium butyrate (SB, n = 23; with 15 females and 8 males). The calves in the SB treatment group were supplemented with 4 g/d of unprotected sodium butyrate (Adimix, Adisseo, China), added to the milk replacer from 4 to 60 days of age. Water and starter were fed ad libitum. The study evaluated several parameters, including feed intake, nutrient digestibility, ruminal pH, ammonia and volatile fatty acids, blood metabolites (glucose, insulin-like growth factor type 1, urea, β-hydroxybutyrate), hemogram, health scores, performance, and feed efficiency. Bull calves were euthanized at 60 days of age for organ comparison, while heifer calves were assessed for carryover effects up to 90 days of age. Data were analyzed independently using linear mixed models using the nlme package in R, and the Artools package for non-parametric categorical outcomes. Although the feed intake and performance variables exhibited differences within weeks, no divergence was observed between treatment groups. Notably, a positive treatment-by-week interaction was identified for starter feed intake (p = 0.02) and total dry matter intake (p = 0.04) during pre-weaning for CON animals. Ruminal parameters, blood metabolites, and hemogram values such as glucose, urea, insulin-like growth factor type 1, mean corpuscular value, lymphocytes, and neutrophils displayed differences within weeks during the pre-weaning stage, but similar results within groups. No differences between supplemented and non-supplemented calves were found across nutrient digestibility, organ development, and histology. Regarding health scores, differences were noted within weeks for fecal and respiratory scores during the pre-weaning stage, and only the respiratory score during the post-weaning stage. Consequently, butyrate supplementation did not elicit improvements or negative effects in the body development or health status of dairy calves.

Benefits of tributyrin on growth performance, gastrointestinal tract development, ruminal bacteria and volatile fatty acid formation of weaned Small-Tailed Han lambs

This study aimed to determine the effects of tributyrin on growth performance, gastrointestinal tract development, ruminal bacteria and volatile fatty acid (VFA) formation. Thirty healthy weaned Small-Tailed Han female lambs at 3 months old with BW 27.5 ± 4.1 kg (mean ± SD) were randomly assigned to five groups of six lambs each, and each group received tributyrin at 0, 0.5, 1.0, 2.0 and 4.0 g/kg in feed. Weights were measured before the start and end of the study. After 15 d adaptation, DMI, feed, faeces and urine were recorded every week. Lambs were sacrificed at d 75. Compared to lambs fed no tributyrin, lambs fed 4.0 g/kg tributyrin had higher average daily BW gain (P = 0.04) and DMI (P < 0.01). Tributyrin reduced nitrogen (P < 0.01), Ca (P < 0.01) and P (P < 0.01) losses derived from faeces and urine. The mostly important, tributyrin increased dorsal sac thickness (P < 0.01), papillae length (P = 0.04) and width (P < 0.01), ventral sac papillae length (P < 0.01) and width (P < 0.01), caudodorsal blind sac thickness (P = 0.02), papillae length (P < 0.01) and width (P < 0.01). Furthermore, tributyrin increased thicknesses of both the duodenum (P < 0.01) and ileum (P = 0.01), and villus heights of the duodenum (P = 0.01), ileum (P < 0.01), jejunum (P < 0.01) and caecum (P = 0.02), but tributyrin decreased duodenal (P < 0.01) and caecal crypt depths (P < 0.01). Tributyrin reduced rumen pH (P < 0.01) while promoting total VFA concentration (P < 0.01). Tributyrin improved the structure of rumen bacteria by enhancing Clostridium (P = 0.04), Butyrivibrio (P < 0.01), Streptococcus (P = 0.04), Prevotella (P = 0.04), Ruminobacter (P = 0.02) and Fibrobacter (P = 0.03). In conclusion, tributyrin could stimulate gastrointestinal tract development by enhancing colonization of rumen VFA-producing bacteria, and dietary supplementation of tributyrin at 4.0 g/kg of DM was recommended for the weaned lambs.

Sodium butyrate promotes gastrointestinal development of preweaning bull calves via inhibiting inflammation, balancing nutrient metabolism, and optimizing microbial community functions

Butyrate promotes the growth and gastrointestinal development of calves. But, the mechanisms behind its effects on signaling pathways of the gastrointestinal tract and rumen microbiome is unclear. This study aimed to reveal transcriptomic pathways of gastrointestinal epithelium and microbial community in response to butyrate supplementation in calves fed a high fiber starter. Fourteen Holstein bull calves (39.9 ± 3.7 kg, 14 d of age) were assigned to 2 groups (sodium butyrate group, SB; control group, Ctrl). The SB group received 0.5% SB supplementation. At d 51, the calves were slaughtered to obtain samples for analysis of the transcriptome of the rumen and jejunum epithelium as well as ruminal microbial metagenome. Sodium butyrate supplementation resulted in a higher performance in average daily gain and development of jejunum and rumen papillae. In both the rumen and jejunum epithelium, SB down-regulated pathways related to inflammation including NF-κB (PPKCB, CXCL8, CXCL12), interleukin-17 (IL17A, IL17B, MMP9), and chemokine (CXCL12, CCL4, CCL8) and up-regulated immune pathways including the intestinal immune network for immunoglobulin A (IgA) production (CD28). Meanwhile, in the jejunum epithelium, SB regulated pathways related to nutritional metabolism including nitrogen metabolism (CA1, CA2, CA3), synthesis and degradation of ketone bodies (HMGCS2, BDH1, LOC100295719), fat digestion and absorption (PLA2G2F, APOA1, APOA4), and the PPAR signaling pathway (FABP4, FABP6, CYP4A11). The metagenome showed that SB greatly increased the relative abundance of Bacillus subtilis and Eubacterium limosum, activated ruminal microbial carbohydrate metabolism pathways and increased the abundance of carbohydrate hydrolysis enzymes. In conclusion, butyrate exhibited promoting effects on growth and gastrointestinal development by inhibiting inflammation, enhancing immunity and energy harvesting, and activating microbial carbohydrate metabolism. These findings provide new insights into the potential mechanisms behind the beneficial effects of butyrate in calf nutrition.

Comparison of the effect of Saccharomyces cerevisiae-Megasphaera elsdenii and buffer on growth performance, digestibility, ruminal histomorphometry, and carcass characteristics of fattening lambs in high concentrate diet

This study aimed to investigate the effect of rumen pH-adjusting additives in the high-concentrated diet on functional traits, nutrient digestion, some meat parameters, and histomorphometry, and rumen histopathology. Twenty-four Arabia male lambs with 3 to 4 months old and initial body weight of 23.9 ± 3.15 kg were used in a completely randomized design with three treatments and eight replicates. The study was 77 days, including 14 days of the adaptation period and 63 days of the record taking and sampling period. The experimental treatments consisted of a control diet, control diet + sodium bicarbonate buffer, control diet + Megasphaera elsdenii, and Saccharomyces cerevisiae (bacterial-yeast). Rumen fluid was taken by stomach tube at 3 h after morning feeding to measure pH. The lambs were weighed every 3 weeks during the period, and the body weight changes, average daily gain, and total weight gain were measured, and the feed conversion ratio was calculated. At the end of the experiment, the lambs were slaughtered, and the longissimus dorsi muscle was prepared to determine the meat parameters. For histological studies, the abdominal rumen sac was sampled. There were no differences among treatments in dry matter intake (DMI), daily weight gain (ADG), and feed conversion ratio (P > 0.05). Propionate concentration was higher in the bacteria-yeast treatment than other treatments (P < 0.05). Protein digestibility was higher in control and bacteria-yeast treatments than buffer treatment (P < 0.05). The percentage of meat protein, carcass weight, and dressing percentage in bacterial-yeast treatment was higher than other treatments (P < 0.05). Rumen wall thickness in the buffer and bacterial-yeast receiving treatments was greater than the control treatment and was significant in the buffer treatment compared to the control treatment (P < 0.05). The thickness of rumen epithelial tissue in the buffer and bacterial-yeast recipient treatments was less than the control treatment (P < 0.05). Rumen papillae thickness was higher in the control treatment than other treatments (P < 0.05). Hydropic degeneration and parakeratosis were less in pH-regulating treatments than in control. The results showed that the use of Megasphaera elsdenii could be an effective way to modulate the ruminal fermentation conditions of lambs fed with high concentrate diets. In addition, to increaseing dressing percentage and meat protein, it can also reduce tissue damage and improve ruminal tissue structure.

Rumen Biogeographical Regions and Microbiome Variation

The rumen is a complex organ that is critical for its host to convert low-quality feedstuffs into energy. The conversion of lignocellulosic biomass to volatile fatty acids and other end products is primarily driven by the rumen microbiome and its interaction with the host. Importantly, the rumen is demarcated into five distinct rumen sacs as a result of anatomical structure, resulting in variable physiology among the sacs. However, rumen nutritional and microbiome studies have historically focused on the bulk content or fluids sampled from single regions within the rumen. Examining the rumen microbiome from only one or two biogeographical regions is likely not sufficient to provide a comprehensive analysis of the rumen microbiome and its fermentative capacity. Rumen biogeography, digesta fraction, and microbial rumen–tissue association all impact the diversity and function of the entirety of the rumen microbiome. Therefore, this review discusses the importance of the rumen biographical regions and their contribution to microbiome variation.

Gastrointestinal structure and function of preweaning dairy calves fed a whole milk powder or a milk replacer high in fat

The composition of milk replacer (MR) for calves greatly differs from that of bovine whole milk, which may affect gastrointestinal development of young calves. In this light, the objective of the current study was to compare gastrointestinal tract structure and function in response to feeding liquid diets having a same macronutrient profile (e.g., fat, lactose, protein) in calves in the first month of life. Eighteen male Holstein calves (46.6 ± 5.12 kg; 1.4 ± 0.50 d of age at arrival; mean ± standard deviation) were housed individually. Upon arrival, calves were blocked based on age and arrival day, and, within a block, calves were randomly assigned to either a whole milk powder (WP; 26% fat, DM basis, n = 9) or a MR high in fat (25% fat, n = 9) fed 3.0 L 3 times daily (9 L total per day) at 135 g/L through teat buckets. On d 21, gut permeability was assessed with indigestible permeability markers [chromium (Cr)-EDTA, lactulose, and d-mannitol]. On d 32 after arrival, calves were slaughtered. The weight of the total forestomach without contents was greater in WP-fed calves. Furthermore, duodenum and ileum weights were similar between treatment groups, but jejunum and total small intestine weights were greater in WP-fed calves. The surface area of the duodenum and ileum did not differ between treatment groups, but the surface area of the proximal jejunum was greater in calves fed WP. Urinary lactulose and Cr-EDTA recoveries were greater in calves fed WP in the first 6 h post marker administration. Tight junction protein gene expression in the proximal jejunum or ileum did not differ between treatments. The free fatty acid and phospholipid fatty acid profiles in the proximal jejunum and ileum differed between treatments and generally reflected the fatty acid profile of each liquid diet. Feeding WP or MR altered gut permeability and fatty acid composition of the gastrointestinal tract and further investigation are needed to understand the biological relevance of the observed differences.

Clearance of Biodegradable Polymer and Polyethylene Films from the Rumens of Holstein Bull Calves

Due to the occurrence of plastic impaction in ruminants and its deleterious effects on health and production, it is necessary to determine the suitability of biodegradable polymers to replace polyethylene-based agricultural plastics, such as hay netting. The objectives of this study were to evaluate the clearance of a polyhydroxyalkanoate (PHA) and poly(butylene succinate-co-adipate) (PBSA) melt-blend polymer from the rumen when fed to cattle and subsequent animal health. Twelve Holstein bull calves were dosed with an encapsulated 13.6 g of PBSA:PHA (Blend), 13.6 g of low-density polyethylene (LDPE), or four empty gelatin capsules (Control) for 30 d. The feed intake, body weight, and body temperature were evaluated, and hemograms were run on d 0 and d 30. On d 31, calves were euthanized to evaluate gross rumen measurements and pathology, papillae length, and polymer residues in rumen contents. No calves presented any signs related to plastic impaction. The feed intake; body weight; rectal temperature; hematological parameters; gross rumen measurements and pathology; and rumen pH and temperature were not affected by treatments. Calves dosed with LDPE had 27 g of undegraded polymer retained in the rumen while Blend calves had only 2 g of fragmented polymers that were 10% of their original size. Agricultural plastics developed from PBSA:PHA may be a suitable alternative to LDPE-based products in the case of animal ingestion and may reduce the incidence of plastic impaction.

Protective Roles of Sodium Butyrate in Lipopolysaccharide-Induced Bovine Ruminal Epithelial Cells by Activating G Protein-Coupled Receptors 41

This study aimed to evaluate whether sodium butyrate (SB) attenuates the ruminal response to LPS-stimulated inflammation by activating GPR41 in bovine rumen epithelial cells (BRECs). We examined the SB regulation of GPR41 and its impact on LPS-induced inflammation using GPR41 knockdown BRECs. The LPS-induced BRECs showed increases in the expression of genes related to pro-inflammation and decreases in the expression of genes related to tight junction proteins; these were attenuated by pretreatment with SB. Compared with that in LPS-stimulated BRECs, the ratio of phosphorylated NF-κB (p65 subunit) to NF-κB (p65 subunit) and the ratio of phosphorylated IκBα to IκBα were suppressed with SB pretreatment. The LSB group abated LPS-induced apoptosis and decreased the expression of Bax, Caspase 3, and Caspase 9 mRNA relative to the LPS group. In addition, the LSB group had a lower proportion of cells in the G0–G1 phase and a higher proportion of cells in the S phase than the LPS group. The mRNA expression of ACAT1 and BDH1 genes related to volatile fatty acid (VFA) metabolism were upregulated in the LSB group compared to those in LPS-induced BRECs. In addition, pretreatment with SB promoted the gene expression of GPR41 in the LPS-induced BRECs. Interestingly, SB pretreatment protected BRECs but not GPR41KD BRECs. Our results suggest that SB pretreatment protects against the changes in BRECs LPS-induced inflammatory response by activating GPR41.

Integration of Long Non-Coding RNA and mRNA Profiling Reveals the Mechanisms of Different Dietary NFC/NDF Ratios Induced Rumen Development in Calves

The aim of the present study was to explore the effects of dietary non-fibrous carbohydrate to neutral detergent fiber (NFC/NDF) ratios on rumen development of calves, and to investigate the mechanisms by integrating of lncRNA and mRNA profiling. Forty-five weaned Charolais hybrid calves [body weight = 94.38 ± 2.50 kg; age = 70 ± 2.69 d] were randomly assigned to 1 of 3 treatment groups with different dietary NFC/NDF ratios: 1.10 (H group), 0.94 (M group) and 0.60 (L group), respectively. The ventral sac of the rumen was sampled for morphological observation and transcriptional sequencing. The average daily gain of calves in the high NFC/NDF ratio group was significantly higher than that in other groups (p < 0.05). Papillae width was largest in high NFC/NDF ratio group calves (p < 0.05). Identified differentially expressed genes that were significantly enriched in pathways closely related to rumen epithelial development included focal adhesion, Wingless-int signaling pathway, thyroid hormone signaling pathway, regulation of actin cytoskeleton and cGMP-PKG signaling pathway. The lncRNA-mRNA network included XLOC_068691 and MOAB, XLOC_023657 and DKK2, XLOC_064331 and PPP1R12A which we interpret to mean they have important regulatory roles in calve rumen development. These findings will serve as a theoretical basis for further analysis of the molecular genetic mechanism of dietary factors affecting rumen development in calves.

Overview of common practices in calf raising facilities

In this literature review, we overview some of the common management practices associated with calf rearing in specialized operations of the United States. Given the growing importance of dairy-beef calves entering the beef production of the United States, we overview aspects related to housing, nutrition, and health events during the pre- and post-weaning period. Based on data on dairy animals, we hypothesize how early life experiences could impact the feedlot performances of dairy-beef animals. Most of the large calf raising operations, where the majority of dairy-beef animals are raised, are located in the Central Great Plains and West regions of the United States. Approximately 80% of calves are individually housed, but the type of housing (e.g., outside hutch, inside a barn) varies based on location of calf-raising facilities. Milk-replacer is fed in more than 80% of operations, while milk (saleable or nonsaleable) is fed in approximately 30% of calf raising facilities (some operations fed more than one type of liquid diet). In addition to liquid feed, water and calf starter are offered ad libitum to calves. Adequate starter intake at weaning is crucial for feed transition from pre- to post-weaning period, which occurs at approximately 2 months of age. Then, calves are mainly housed in group pens and transition from calf-starter to total mixed ration (TMR). Health challenges such as scours and bovine respiratory disease (BRD) can hinder the performance of calves and are major causes of morbidity and mortality in calf ranches. Transportation at a very young age and comingling with animals from other dairies can increase the risk of diseases. Current research efforts are focusing on determining individual factors such as body weight (BW) at arrival or biomarkers of inflammation and stress that can be predictive of disease morbidity, mortality, and performance of calves. Future research should focus on how to utilize this information to optimize management and to develop targeted preventative strategies to reduce incidence of diseases and mortality and improve performance during the pre-weaned period. Also, more research is needed to understand how colostrum management, housing, and nutrition can impact the adult performance of dairy-beef animals.

Effect of the Length of Oat Hay on Growth Performance, Health Status, Behavior Parameters and Rumen Fermentation of Holstein Female Calves

The aim of this study was to evaluate the effect of the length of oat hay on the performance, health, behavior, and rumen fermentation of dairy calves. For this purpose, two hundred and ten healthy two-day-old Holstein dairy calves were randomly allocated into three groups: basic diet (calf starter) without hay (CON), or a basic diet with oat hay at either long (OL: 10-12 cm) or short (OS: 3-5 cm) length cut. The basic diet was fed from day 4, while the hay was offered from day 14. All calves were weaned at day 56 and remained in their individual hutches till the end of the trial (day 70). Calf starter intake and fecal scores were recorded daily. Bodyweight, body size, and rumen fluid samples were collected biweekly before weaning and weekly after weaning. Overall, providing oat hay (OS and OL) in the diet increased the body weight, starter intake, and average daily gain compared to the CON group. Similarly, feeding oat hay improved rumen fermentation. More specifically, hay enhanced the rumen pH and changed the rumen fermentation type. Hay fed calves spent more time on rumination but less time performing abnormal behaviors compared to control. As it can be concluded, feeding oat hay to calves enhances the growth performance, rumen fermentation, and normal calf behaviors, implying improved animal welfare irrespective of the hay length.

Longitudinal assessment revealed the shifts in rumen and colon mucosal-attached microbiota of dairy calves during weaning transition

The objectives of this study were to investigate the shifts in rumen and colon mucosa-associated microbiota in dairy calves fed a high milk replacer feeding rate before and after weaning and to determine whether such shifts are associated with tissue physiological measures. Longitudinal biopsy was performed to collect rumen and colon mucosal tissues of 4 ruminally cannulated Holstein dairy bull calves (weaned at 6 wk of age) at the end of wk 5 (before weaning), 7 (weaning adaptation) and 12 (after weaning), and were used to assess mucosa-associated microbiota and their changes using amplicon sequencing. Both rumen and colon mucosa-associated bacterial communities shifted during the weaning process, as evidenced by their clear separation among 3 different weaning periods and increased α diversity (Shannon and Chao1 indices) during weaning transition. Among the 3 dominant bacterial phyla identified (relative abundance >1.0%), the relative abundance of Proteobacteria and Bacteroidetes decreased in the rumen mucosa, whereas the relative abundance of Firmicutes increased in both rumen and colon mucosa during weaning transition. In the rumen mucosa, Campylobacter (0.6-22.1%) gradually became prevalent during weaning transition, whereas Succinivibrio (6.2-10.3%) and Prevotella 1 (4.7-10.5%) were dominant regardless of weaning transition. In the colon mucosa, Bacteroides (12.8-25.4%) was dominant during weaning transition, although its relative abundance decreased after weaning. In the meantime, relative abundance of uncultured Lachnospiraceae increased from 2.2% to 25.7% during this period. In addition, genera Pyramidobacter (in the rumen mucosa) and Lachnoclostridium (in the colon mucosa) were positively correlated with rumen papilla surface area and colon mucosal thickness, respectively. Moreover, genera Ruminococcaceae UCG-005 and Sharpea in the rumen mucosa were positively correlated with the molar proportion of propionate and butyrate, respectively. Overall, our findings revealed that rumen and colon mucosa-associated bacterial communities altered in response to the weaning transition, and some bacterial taxa in these communities may have positive effects on rumen and colon mucosa development during this period.

Establishment and transcriptomic analyses of a cattle rumen epithelial primary cells (REPC) culture by bulk and single-cell RNA sequencing to elucidate interactions of butyrate and rumen development

As a critical and high-value tool to study the development of rumen, we established a stable rumen epithelial primary cell (REPC) culture from a two-week-old Holstein bull calf rumen epithelial tissue. The transcriptomic profiling of the REPC and the direct effects of butyrate on gene expression were assessed. Correlated gene networks elucidated the putative roles and mechanisms of butyrate action in rumen epithelial development. The top networks perturbed by butyrate were associated with epithelial tissue development. Additionally, two critical upstream regulators, E2F1 and TGFB1, were identified to play critical roles in the differentiation, development, and growth of epithelial cells. Significant expression changes of upstream regulators and transcription factors provided further evidence in support that butyrate plays a specific and central role in regulating genomic and epigenomic activities influencing rumen development. This work is the essential component to obtain a complete global landscape of regulatory elements in cattle and to explore the dynamics of chromatin states in rumen epithelial cells induced by butyrate at early developmental stages.

Changes in the Solid-, Liquid-, and Epithelium-Associated Bacterial Communities in the Rumen of Hu Lambs in Response to Dietary Urea Supplementation

The rumen bacteria in the solid, liquid, and epithelial fractions are distinct and play important roles in the degradation of urea nitrogen. However, the effects of urea on rumen bacteria from the three fractions remain unclear. In this study, 42 Hu lambs were fed a total mixed ration based on concentrate and roughage (55:45, dry matter basis) and randomly assigned to one of three experimental diets: a basal diet with no urea (UC, 0 g/kg), a basal diet supplemented with low urea levels (LU, 10 g/kg DM), and a basal diet supplemented with high urea levels (HU, 30 g/kg DM). After an 11-week feeding trial, six animals from each treatment were harvested. Rumen metabolites levels were measured, and bacteria of the rumen solid, liquid, and epithelial fractions were examined based on 16S rRNA gene sequencing. Under urea supplementation, the concentrations of ammonia and butyrate in the rumen increased, whereas the concentration of propionate decreased. The population of total protozoa was the highest in the LU treatment. Prevotella 1 was the most abundant genus in all samples. The unclassified Muribaculaceae, bacteria within the families Lachnospiraceae and Ruminococcaceae, and Christensenellaceae R7 were abundant in the solid and liquid fractions. Butyrivibrio 2 and Treponema 2 were the abundant bacteria in the epithelial fraction. Principal coordinate analysis showed separation of the solid, liquid and epithelial bacteria regardless of diet, suggesting that rumen fraction had stronger influences on the bacterial community than did urea supplementation. However, the influences on the bacterial community differed among the three fractions. In the solid and liquid fractions, Succinivibrionaceae UCG 001 and Prevotella 1 showed decreased abundance with dietary urea supplementation, whereas the abundance of Oscillospira spp. was increased. Howardella spp. and Desulfobulbus spp. were higher in the epithelial fraction of the UC and LU treatments relative to HU treatment. Comparisons of predictive function in the rumen solid, liquid, and epithelial fractions among the three treatments also revealed differences. Collectively, these results reveal the change of the rumen bacterial community to dietary urea supplementation.

Peanut skin in diet alters average daily gain, ruminal and blood metabolites, and carcass traits associated with Haemonchus contortus infection in meat goats

The aim of this study was to determine the effects of tannin-rich peanut skin (PS) supplementation on growth performance, ruminal and blood metabolites, and carcass traits associated with internal parasite infection in meat goats under confined conditions. Twenty-one Kiko crossbred male goats were blocked by body weight (BW) and randomly assigned to one of 3 treatment groups. Experimental diets contained different levels of peanut (Arachis hypogaea) skin replacing alfalfa (Medicago sativa) pellets (ALP) in a control diet. Experimental treatments included: 30% ALP (control), 15% PS and 15% ALP, and 30% PS. Peanut skin was incorporated in the grain mix portion of the diets. Animals were fed once daily, and the intake was adjusted every 3 to 4 d. Each animal was each artificially infected with 5,000 larvae of the 3rd stage of barber's pole worm (Haemonchus contortus). Body weights, dry matter intake (DMI), and fecal samples for fecal egg counts (FEC) were taken at d 0, 12, 23, and 41. Rumen fluid and blood samples were collected at d 45. The performance period lasted 45 d and at the completion of the study, goats were harvested, and carcass characteristics, abomasal worm counts were measured. The results showed that DMI, BW, carcass traits, and meat color were not affected by PS supplementation, whereas average daily gain (ADG, P < 0.01), blood glucose (P < 0.001), phosphorus (P < 0.05), and cholesterol levels (P < 0.001) significantly increased with increasing levels of PS supplementation. There was a linear (P < 0.01) reduction in rumen acetate to propionate ratio, ammonia-nitrogen, FEC, and H. contortus worm counts, with increasing levels of PS supplementation. This study shows that PS supplementation up to 30% of the diet can improve ADG and rumen fermentation while reducing gastrointestinal parasite infection in meat goats.

Infusion of sodium butyrate promotes rumen papillae growth and enhances expression of genes related to rumen epithelial VFA uptake and metabolism in neonatal twin lambs

The objective of this study was to evaluate the effect of sodium butyrate (SB) infusion on rumen papillae growth and volatile fatty acid (VFA) uptake and metabolism in neonatal lambs. Seven pairs of newborn twin lambs were used. Within each pair, lambs were assigned to receive an oral infusion of SB at 0.36 g/kg body weight (BW) (SB, n = 7) or the same volume of saline (Con, n = 7). Treatments were administered from 10 to 49 d of age, when all lambs were slaughtered. Results showed that the average daily feed intake (ADFI) of starter, average daily gain (ADG), BW of lambs at ages of 5 and 6 wk in SB group were greater (P < 0.05) than those in Con group. Infusion of SB increased (P < 0.05) the concentrations of acetate, butyrate, and total VFA in the rumen fluid and elevated (P < 0.05) the levels of β-hydroxybutyrate acid (BHBA), insulin-like growth factor-1 (IGF-1), and insulin in plasma. Infusion of SB promoted rumen papillae growth, depicted by higher emptied rumen weight, larger rumen papillae length, width, and surface area, and greater thickness of stratum corneum and total epithelium. Sodium butyrate infusion upregulated (P < 0.05) mRNA expression of cyclin A2, cyclin D1, and cyclin-dependent kinases 6 (CDK6), and downregulated (P < 0.05) mRNA expression of caspase-3 and Bcl-2-associated X protein (Bax) in the rumen epithelia. Moreover, SB infusion also upregulated (P < 0.05) mRNA expression of insulin-like growth factor-1 receptor (IGF-1R), and insulin-like growth factor-binding protein 5 (IGFBP-5), and downregulated (P < 0.05) mRNA expression of insulin-like growth factor-binding protein 3 (IGFBP-3) in the rumen epithelia. Sodium butyrate infusion also enhanced (P < 0.05) gene expressions of monocarboxylate transporter isoform 1 (MCT1), downregulated in adenoma (DRA), 3-hydroxy-3-methylglutaryl-CoA synthase isoform 2 (HMGCS2), and 3-hydroxy-3-methylglutaryl-CoA lyase (HMGCL), while depressed (P < 0.05) mRNA expression of sodium/proton exchanger isoform 2 (NHE2) in the rumen epithelia. Our results suggest that the SB infusion can improve animal performance, promote the ruminal papillae growth, and enhance expression of genes related to ruminal epithelial VFA uptake and metabolism in preweaning twin lambs. These findings provide a better understanding of the molecular mechanism of SB promoting rumen epithelial development and function in preweaning lambs.

Dietary supplementation with glucogenic precusors and fatty acids improves performance and health of periparturient dairy cows

This experiment aimed to make a comparison between the effect of a mix of two energy preparations (a glucogenic preparation (G) and a free fatty acid preparation (F)), administered in the diet during the transition period over different periods of time (5 or 8 weeks), on the animal condition, feed intake, yield and composition of milk, and blood and urine parameters. The experimental additive was a mixture (1:1) of two energy preparations, namely, a loose mixture of propylene glycol and sodium propionate and a free fatty acid preparation in the form of rumen-undegradable pellets. The study included 50 Polish Black-and-White Holstein–Friesian dairy cows, allocated into five treatment groups, including one control (C) and four experimental ones (G1F1, G2F2, G2F1 and G1F2). The preparations were mixed at a 1:1 weight ratio (500 g per head, comprising 250G and 250F) and they were administered to all experimental groups of cows daily as a component of the experimental concentrate for 5 weeks (from the 2nd week before the expected calving and until the 3rd week of lactation). From the 4th until the 6th week of lactation, the supplementation in the experimental groups changed and animals received either no additive (G1F1), or were continuously supplemented with the G–F mix (G2F2), or received only G (G2F1) or only F (G1F2). The preparations used in the study had a long-term influence on the increase in the milk yield of cows, on the improvement of their health condition, and on the reduction of weight loss. The study results confirmed that prolongation of the supplementation until the 6th week of lactation may cause favourable changes in animal performance and milk quality. Due to different modes of action, the simultaneous supplementation of G and F reduced the negative energy balance in the cow and improved milk production and composition. The best results were obtained after administration of the mixture (1:1) of the G and F at the dose of 500 g/cow.day over the 8-week periparturient period.

Effect of a butyrate-fortified milk replacer on gastrointestinal microbiota and products of fermentation in artificially reared dairy calves at weaning

Enrichment of calf diets with exogenous butyrate has shown promise as a promotor of calf growth and intestinal development. However, the impact of dietary derived butyrate on the gut microbiota and their potential role, in turn, as mediators of its effect on calf growth and development is not known. Here, the effects of butyrate supplementation on rumen and hindgut microbiota and fermentation profiles were assessed in 16 Holstein-Friesian bull calves randomly assigned to one of two groups: Control (CON) fed conventional milk replacer or Sodium-Butyrate (SB – added to milk replacer) from days 7 to 56 of life. In the colon, total short chain fatty acid (SCFA), propionate and acetate concentrations were increased by SB (P < 0.05). 16S rRNA gene amplicon sequencing showed cecal abundance of butyrate producers Butyrivibrio and Shuttleworthia were decreased by SB (P < 0.05), while that of the propionate producer Phascolarctobacterium was higher (P < 0.05). Mogibacterium is associated with impaired gut health and was reduced in the cecum of SB calves (P < 0.05). These data show that the beneficial effects of SB on growth and performance occur in tandem with changes in the abundance of important SCFA producing and health-associated bacteria in the hindgut in milk-fed calves.

Effect of individual SCFA on the epithelial barrier of sheep rumen under physiological and acidotic luminal pH conditions

The objective of this study was to investigate whether individual short-chain fatty acids (SCFA) have a different potential to either regulate the formation of the ruminal epithelial barrier (REB) at physiological pH or to damage the REB at acidotic ruminal pH. Ruminal epithelia of sheep were incubated in Ussing chambers on their mucosal side in buffered solutions (pH 6.1 or 5.1) containing no SCFA (control), 30 mM of either acetate, propionate or butyrate, or 100 mM acetate. Epithelial conductance (Gt), short-circuit current (Isc), and fluorescein flux rates were measured over 7 h. Thereafter, mRNA and protein abundance, as well as localization of the tight junction proteins claudin (Cldn)-1, -4, -7, and occludin were analyzed. At pH 6.1, butyrate increased Gt and decreased Isc, with additional decreases in claudin-7 mRNA and protein abundance (each P < 0.05) and disappearance of Cldn-7 immunosignals from the stratum corneum. By contrast, the mRNA abundance of Cldn-1 and/or Cldn-4 were upregulated by 30 mM propionate, 30 mM butyrate, or 100 mM acetate (P < 0.05), however, without coordinated changes in protein abundance. At luminal pH 5.1, neither Gt, Isc, nor TJ protein abundance was altered in the absence of SCFA; only fluorescein flux rates were slightly increased (P < 0.05) and fluorescein signals were no longer restricted to the stratum corneum. The presence of acetate, propionate, or butyrate at pH 5.1 increased fluorescein flux rates and Gt, and decreased Isc (each P < 0.05). Protein abundance of Cldn-1 was decreased in all SCFA treatments but 30 mM butyrate; abundance of Cldn -4 and -7 was decreased in all SCFA treatments but 30 mM acetate; and abundance of occludin was decreased in all SCFA treatments but 30 mM propionate (each P < 0.05). Immunofluorescence staining of SCFA-treated tissues at pH 5.1 showed disappearance of Cldn-7, discontinuous pattern for Cldn-4 and blurring of occludin and Cldn-1 signals in tight junction complexes. The fluorescein dye appeared to freely diffuse into deeper cell layers. The strongest increase in Gt and consistent decreases in the abundance and immunosignals of tight junction proteins were observed with 100 mM acetate at pH 5.1. We conclude that SCFA may contribute differently to the REB formation at luminal pH 6.1 with possible detrimental effects of butyrate at 30 mM concentration. At luminal pH 5.1, all SCFA elicited REB damage with concentration appearing more critical than SCFA species.