A Polyherbal Mixture with Nutraceutical Properties for Ruminants: A Meta-Analysis and Review of BioCholine Powder

BioCholine Powder is a polyherbal feed additive composed of Achyrantes aspera, Trachyspermum ammi, Azadirachta indica, and Citrullus colocynthis. The objective of this study was to analyze published results that support the hypothesis that the polyherbal product BioCholine Powder has rumen bypass choline metabolites through a meta-analysis and effect size analysis (ES). Using Scopus, Web of Science, ScienceDirect, PubMed, and university dissertation databases, a systematic search was conducted for experiments published in scientific documents that evaluated the effects of BioCholine supplementation on the variables of interest. The analyzed data were extracted from twenty-one publications (fifteen scientific articles, three abstracts, and three graduate dissertations available in institutional libraries). The studies included lamb growing-finishing, lactating ewes and goats, calves, and dairy cows. The effects of BioCholine were analyzed using random effects statistical models to compare the weighted mean difference (WMD) between BioCholine-supplemented ruminants and controls (no BioCholine). Heterogeneity was explored, and three subgroup analyses were performed for doses [(4 (or 5 g/d), 8 (10 g/d)], supplementation in gestating and lactating ewes (pre- and postpartum supplementation), and blood metabolites by species and physiological state (lactating goats, calves, lambs, ewes). Supplementation with BioCholine in sheep increased the average daily lamb gain (p < 0.05), final body weight (p < 0.01), and daily milk yield (p < 0.05) without effects on intake or feed conversion. Milk yield was improved in small ruminants with BioCholine prepartum supplementation (p < 0.10). BioCholine supplementation decreased blood urea (p < 0.01) and increased levels of the liver enzymes alanine transaminase (ALT; p < 0.10) and albumin (p < 0.001). BioCholine doses over 8 g/d increased blood glucose, albumin (p < 0.10), cholesterol, total protein, and globulin (p < 0.05). The ES values of BioCholine in retained energy over the control in growing lambs were +7.15% NEm (p < 0.10) and +9.25% NEg (p < 0.10). In conclusion, adding BioCholine Powder to domestic ruminants' diets improves productive performance, blood metabolite indicators of protein metabolism, and liver health, showing its nutraceutical properties where phosphatidylcholine prevails as an alternative that can meet the choline requirements in ruminants.

A novel splice variant of goat CPT1a gene and their diverse mRNA expression profiles

The Alternative splicing (AS) of Carnitine palmitoyltransferase 1a (CPT1a) and their expression profiles had never been illuminated in goats until now. Herein, a novel splice transcript in the CPT1a gene that is predicted to result in the skipping of exons 6-19 (CPT1a-sv1) has been isolated in addition to the full-length transcript in goats. The result of RT-PCR showed that CPT1a-sv1 is 606 bp in length and consists of 6 exons. A novel exon 6 was consisted of partial exon 5 and partial exon 19, compared to that in CPT1a. RT-qPCR analysis showed that the expression patterns of CPT1a and CPT1a-sv1 are spatially different. In both kid and adult goats, the CPT1a transcript is strongly expressed in the liver, spleen, lung, kidney, and brain tissues. However, CPT1a-sv1 has a strong tissue-specific expression pattern, with moderate RNA levels in the liver and brain of kids, while highly expressed in the liver and minimally expressed in the brain of adults. We observed two transcripts to be involved in brain development. These findings improve our understanding of the function of the CPT1a gene in goats and provide information on the molecular mechanism of AS events.

Dietary supplementation of sodium butyrate enhances lactation performance by promoting nutrient digestion and mammary gland development in dairy cows

This experiment was to evaluate the influence of sodium butyrate (SB) addition on milk production, ruminal fermentation, nutrient digestion, and the development and metabolism regulation of the mammary gland in dairy cows. Forty Holstein dairy cows averaging 710 ± 18.5 kg body weight, 72.8 ± 3.66 d in milk (DIM), and 41.4 ± 1.42 kg/d milk production were divided into four treatments blocked by DIM and milk production. Treatments were control group, low SB, medium SB, and high SB with 0, 100, 200 and 300 g/d of SB addition per cow, respectively. The study lasted for 105 d. Production of milk, milk protein and lactose quadratically increased (P < 0.05), while fat-corrected milk, energy-corrected milk and milk fat yields linearly increased (P < 0.05) with increasing SB addition. The digestibility of dietary dry matter, organic matter, and crude protein linearly increased (P < 0.05), whereas the digestibility of ether extract, neutral detergent fibre, and acid detergent fibre quadratically increased (P < 0.05). Ruminal pH quadratically decreased (P = 0.04), while total volatile fatty acids (VFA) quadratically increased (P = 0.03) with increasing SB addition. The acetic acid to propionic acid ratio increased (P = 0.03) linearly due to the unaltered acetic acid molar percentage and a linear decrease in propionic acid molar percentage. Ruminal enzymatic activity of carboxymethyl-cellulase and α-amylase, populations of total bacteria, total anaerobic fungi, total protozoa, Ruminococcus albus, R. flavefaciens, Butyrivibrio fibrisolvens, Fibrobacter succinogenes, and Ruminobacter amylophilus linearly increased (P < 0.05). Blood glucose, urea nitrogen, and non-esterified fatty acids linearly decreased (P < 0.05), while total protein concentration linearly increased (P = 0.04). Moreover, the addition of SB at 200 g/d promoted (P < 0.05) mRNA and protein expression of PPARγ, SREBF1, ACACA, FASN, SCD, CCNA2, CCND1, PCNA, Bcl-2, GPR41, and the ratios of p-Akt/Akt and p-mTOR/mTOR, but decreased (P < 0.05) mRNA and protein expressions of Bax, caspase-3, and caspase-9. The results suggest that milk production and milk fat synthesis increased with SB addition by stimulating rumen fermentation, nutrient digestion, gene and protein expressions concerned with milk fat synthesis and mammary gland development.

Effects of Essential Oil and/or Encapsulated Butyrate on Fecal Microflora in Neonatal Holstein Calves

This study was conducted to investigate the effects of feeding oregano essential oil, butyrate, and its mixture on the intestinal microbial diversity of calves. A completely randomized experimental design was used. Sixty-four healthy neonatal Holstein female calves with birth weight ≥ 35 kg were randomly divided into one control and three treatments (16 calves per group). The control group was fed normally, and the treatment group was fed oregano essential oil, butyrate, and their mixture, respectively. The experiment lasted for 70 days, and the lactation period lasted for 56 days. On days 55 and 70, rectal fecal samples from five calves were collected from each group for 16S rRNA amplification and sequencing. The results showed as follows: (1) the three treatments had no significant effects on the intestinal microbial community diversity, community uniformity, and community pedigree diversity of calves (p > 0.05). (2) At the phylum level, Firmicutes, Bacteroidota, Spriochatetota, Actinobacteriota, Firmicutes, and Bacteroidota gates of the main bacteria were detected in feces. (3) At the genus level, the top ten species with relative abundance detected are: norank_ F_Muribaaculaceae, Ruminococcus, unclassified_ F_ Lachnospiraceae, UCG-005, Prevotelaceae_NK3B31_Group, Prevotella, Bacteroides, Rikenellaceae_RC9_Gut_Group, and Faecalibacterium, Alloprevotella. (4) LEfSe analysis results show that the species with significant differences in the control group were f__Lachnospiraceae, o__Lachnospirales, o__Coriobacteriales, and c__Coriobacteriia, g__Megasphaera; in the essential oil group were g__Lachnospiraceae_AC2044_group, o__Izemoplasmatales, g__norank_f__norank_o__Izemoplasmatales, and f__norank_o__Izemoplasmatales; in the sodium butyrate group were g__Lachnospiraceae_NK4A136_group, and g__Sharpea, g__Fournierella; in the mixed group were g__Flavonifractor, and g__UBA1819. (5) The functional prediction analysis of calf gut microbes, found on the KEGG pathway2, shows that essential oil significantly improved membrane transport, Sodium butyrate inhibits lipid metabolism and improves the body's resistance to disease. (p < 0.05). (6) The effects of each treatment on the intestinal microbial structure of calves did not last for 14 days after the treatment was stopped. In conclusion, the addition of oregano essential oil, butyrate, and its mixtures to milk fed to calves can modulate the microbial structure, and it is recommended that oregano essential oil and butyrate be used separately, as a mixture of the two can increase the rate of diarrhea in calves.

3D sheep rumen epithelial structures driven from single cells in vitro

Ruminants play a vital economic role as livestock, providing high-quality protein for humans. At present, 3D-cultured ruminant abomasum and intestinal organoids have been successfully established to study host and pathogen interaction. The rumen is a unique digestive organ of ruminants that occupies 70% of the volume of the digestive tract and its microbiota can decompose lignocellulose to support animal growth. Here we report a method for culturing rumen epithelial organoids. We found that single rumen epithelial cells form self-organized 3D structures representative of typical stratified squamous epithelium, which is similar to rumen epithelium. EGF, Noggin, Wnt3a, IGF-1, and FGF-10 significantly enhanced the seeding efficiency of organoids. Moreover, the inclusion of CHIR-99021, A83-01, SB202190, and Y-27632 is crucial for organoid formation and maintenance. Importantly, we demonstrate that rumen epithelial cells retain their ability to form organoids after passage, cryopreservation, and resuscitation. The rumen epithelial organoids express rumen cell type-specific genes, uptake fatty acids, and generate 2D cultures. In summary, our data demonstrate that it is feasible to establish organoids from single rumen epithelial cells, which is a novel in vitro system that may reduce the use of experimental animals.

Mammary gland, kidney and rumen urea and uric acid transporters of dairy cows differing in milk urea concentration

The milk urea concentration (MUC) serves as indicator of urinary nitrogen emissions, but at comparable crude protein (CP) intake, cows with high (HMU) and low (LMU) MUC excrete equal urea amounts. We hypothesized that urea and uric acid transporters and sizes of the kidney, mammary gland, and rumen account for these phenotypes. Eighteen HMU and 18 LMU Holstein dairy cows fed a low (LP) and normal (NP) CP diet were studied. Milk, plasma and urinary urea concentrations were greater with NP feeding, while plasma and urinary urea concentrations were comparable between phenotypes. Milk and plasma uric acid concentrations were higher with LP feeding but not affected by phenotype. The milk-urine uric acid ratio was greater in HMU cows. The mRNA expressions of the ruminal urea transporter SLC14A1 and AQP10, the mammary gland and rumen AQP3, and the mammary gland uric acid transporter ABCG2 were not affected by group or diet. Renal AQP10, but not AQP3, AQP7, and SLC14A2 expressions, and the kidney weights were lower in HMU cows. These data indicate that renal size and AQP10 limit the urea transfer from blood to urine, and that MUC determines if uric acid is more released with milk or urine.

Feet and legs malformation in Nellore cattle: genetic analysis and prioritization of GWAS results

Beef cattle affected by feet and legs malformations (FLM) cannot perform their productive and reproductive functions satisfactorily, resulting in significant economic losses. Accelerated weight gain in young animals due to increased fat deposition can lead to ligaments, tendon and joint strain and promote gene expression patterns that lead to changes in the normal architecture of the feet and legs. The possible correlated response in the FLM due to yearling weight (YW) selection suggest that this second trait could be used as an indirect selection criterion. Therefore, FLM breeding values and the genetic correlation between FLM and yearling weight (YW) were estimated for 295,031 Nellore animals by fitting a linear-threshold model in a Bayesian approach. A genome-wide association study was performed to identify genomic windows and positional candidate genes associated with FLM. The effects of single nucleotide polymorphisms (SNPs) on FLM phenotypes (affected or unaffected) were estimated using the weighted single-step genomic BLUP method, based on genotypes of 12,537 animals for 461,057 SNPs. Twelve non-overlapping windows of 20 adjacent SNPs explaining more than 1% of the additive genetic variance were selected for candidate gene annotation. Functional and gene prioritization analysis of candidate genes identified six genes (ATG7, EXT1, ITGA1, PPARD, SCUBE3, and SHOX) that may play a role in FLM expression due to their known role in skeletal muscle development, aberrant bone growth, lipid metabolism, intramuscular fat deposition and skeletogenesis. Identifying genes linked to foot and leg malformations enables selective breeding for healthier herds by reducing the occurrence of these conditions. Genetic markers can be used to develop tests that identify carriers of these mutations, assisting breeders in making informed breeding decisions to minimize the incidence of malformations in future generations, resulting in greater productivity and animal welfare.

Effects of excessive urea on rumen morphology and microbiota in Jianzhou Da'er goat (Capra hircus)

Urea is frequently used as a protein supplement in ruminant diets, but if used improperly, it can easily result in urea poisoning. The purpose of this study was to explore the effects of excessive urea feeding on rumen pathology and microbial diversity of the Jianzhou Da'er goat (Capra hircus). In this study, 9 male Jianzhou Da'er goats with an average weight of 22.9 kg were randomly divided into the control group (0% urea), 5% urea group and 10% urea group (dry matter basis, 3 goats per group). Morphological differences of rumen tissues were analyzed by Hematoxylin-Eosin staining and Prussian blue staining, and rumen microorganisms differences were analyzed by 16S rDNA sequencing on the Illumina Novaseq platform. Histopathological analysis showed that the length of rumen papilla in the 5% urea and 10% urea groups were shortened compared to the control group, and the thickness of the stratum corneum and muscular layer were significantly thinned (P < 0.05). 16S rRNA sequencing analysis indicated that microbial richness and diversity were significantly lower in goats fed on 5% urea or 10% urea, the abundance of Prevotella ruminicola was significantly decreased (P < 0.05), and the abundance of Ruminobacter amylophilus was significantly increased (P < 0.05), as compared with the control group. This study indicated that feeding 5% and 10% urea could damage rumen tissue morphology. Feeding 10% urea significantly reduced rumen microbial diversity and the abundance of Prevotella ruminicola, but increased the abundance of Ruminobacter amylophilus.

Prepartum maternal supplementation of Capsicum oleoresin improves colostrum quality and buffalo calves' performance

The present study aims to evaluate the effects of prepartum maternal supplementation of Capsicum oleoresin (CAP) on colostrum quality and growth performance in newborn buffalo calves. Twelve multiparous buffaloes were randomly assigned to two groups starting from 4 weeks prepartum: the control group with a basal diet (CON) and the treatment group with a basal diet supplemented with 20 mg CAP/kg dry matter (CAP20). After birth, all calves were weighed and received colostrum from their respective dam directly within 2 h. After that, calves received pasteurized milk and starter feed till 56 days of age. The results showed that CAP increased lactose (P < 0.05) in colostrum, and it tended to increase monounsaturated fatty acids; however, it decreased colostrum urea nitrogen (P < 0.10). CAP did not affect colostrum yield and immunoglobulin G and M concentrations. The weekly starter intake was not affected by maternal CAP supplementation during the first 6 weeks of life. There was an increasing tendency in weekly starter intake from weeks 7 and 8 (P < 0.10) in CAP20 compared with CON. At 7 days of age, calves in CAP20 had higher immunoglobulin G (P < 0.05) and a decreased tendency in calves' serum glucose compared with CON. Additionally, maternal CAP supplementation increased calves' serum β-hydroxybutyric acid (P < 0.05) and tended to increase total protein (P < 0.10), while decreased non-esterified fatty acids (P < 0.05) at 56 days of age. Calves in CAP20 had higher final withers height, final heart girth, average withers height, and average heart girth than the CON (P < 0.05). These results suggest that maternal CAP supplementation could improve colostrum quality and positively affect the performance of buffalo calves.

Tributyrin administration improves intestinal development and health in pre-weaned dairy calves fed milk replacer

Butyrate and its derivatives possess various nutritional and biological benefits for mammals, whereas its effects on dairy calves have not been well characterized. This study evaluated the effects of tributyrin administration on blood immune, intestinal immune and barrier functions, and microbial composition of pre-weaned dairy calves. Twenty newborn Holstein bull calves were randomly assigned into a control group (no tributyrin supplementation, CON; n = 10) or a treatment group (supplemented with tributyrin at 2 g/L of milk, TRB; n = 10). The results showed that diarrhea frequency was decreased significantly by tributyrin administration from d 29 to 56 (P < 0.001) and the whole period (P = 0.003, d 1 to 56) though no significant effects were observed on growth performance. For blood metabolites, tributyrin administration significantly reduced the concentration of interleukin-1β (IL-1β) on d 28 (P = 0.001) and tended to reduce the concentration of serum amyloid A on d 56 (P = 0.079), whereas serum oxidative status parameters were not affected. For intestinal development, tributyrin administration increased the villus height (P < 0.001) and the ratio of villus height to crypt depth (P = 0.046) in the jejunum, and the villus height in the ileum (P = 0.074). Furthermore, toll-like receptor 2 (TRL2, P = 0.045) and IL-1β (P = 0.088) gene expressions were downregulated, while claudin-4 (P = 0.022) gene expression was upregulated in the jejunum following tributyrin administration. In the ileum, claudin-4 (P = 0.029) and G-protein coupled receptor 41 (P = 0.019) gene expressions were upregulated in the TRB group compared to CON. No significantly higher abundances of microbiota were found in the jejunum or ileum of calves in the CON group. In the TRB group, supplementing tributyrin significantly increased the abundance of short-chain fatty acid (SCFA)-producing bacteria, including Ruminococcaceae, Lachnospiraceae, Prevotella and Rikenellaceae (LDA >3.5, P < 0.05), which was negatively associated with inflammatory gene expression (TLR2 and IL-1β) but positively associated with intestinal barrier genes (claudin-4) and morphological parameters (P < 0.05). In conclusion, supplementing tributyrin in milk replacer could improve intestinal development and health of pre-weaned dairy calves by stimulating SCFA-producing bacteria colonization, enhancing intestinal barrier functions and suppressing inflammatory responses.

Early feeding strategies in lambs affect rumen development and growth performance, with advantages persisting for two weeks after the transition to fattening diets

This study aimed to explore the effects of early feeding strategies on the growth and rumen development of lambs from pre-weaning to the transition to fattening diets. Ninety-six newborn, male lambs with similar body weights were randomly assigned to three treatments: fed starter at 42 days old + weaned at 56 days old (Ctrl, n = 36), fed starter at 7 days old + weaned at 56 days old (ES, n = 36), and fed starter at 7 days old + weaned at 28 days old (ES + EW, n = 24). The fattening diets of all lambs were gradually replaced from 60 to 70 days of age. Six randomly selected lambs from each treatment were slaughtered at 14, 28, 42, 56, 70, and 84 days of age. The results showed that the richness and diversity of rumen microbiota of lambs in the Ctrl group were distinct from those of lambs in the other groups at 42 days of age. Moreover, transcriptome analysis revealed 407, 219, and 1,211 unique differentially expressed genes (DEGs) in the rumen tissue of ES vs. Ctrl, ES vs. ES + EW, and ES + EW vs. Ctrl groups, respectively, at 42 days of age. Different early feeding strategies resulted in differences in ruminal anatomy, morphology, and fermentation in lambs from 42 to 84 days of age (P < 0.05). Lambs in the ES + EW group had a higher average starter diet intake than those in the other groups (P < 0.05) from 28 to 56 days of age, which affected their growth performance. After 42 days of age, the body and carcass weights of lambs in the ES and ES + EW groups were higher than those in the Ctrl group (P < 0.05). These findings demonstrate that feeding lambs with a starter diet at 7 days of age and weaning them at 28 days of age can promote rumen development and improve growth performance, and this advantage persists for up to 2 weeks after transition to the fattening diet.

Alterations in Skeletal Muscle mRNA Abundance in Response to Ethyl-Cellulose Rumen-Protected Methionine during the Periparturient Period in Dairy Cows

This study aimed to evaluate the effect of feeding ethyl cellulose rumen-protected methionine (RPM) on skeletal muscle mRNA abundance during the periparturient period. Sixty multiparous Holstein cows were used in a block design and assigned to either a control or RPM diet. The RPM was supplied from −28 to 60 days in milk (DIM) at a rate of 0.09% (prepartum) or 0.10% (postpartum) of dry matter (DM), ensuring a Lys:Met in the metabolizable protein of ~2.8:1. Muscle biopsies were collected at −21, 1, and 21 DIM. Thirty-five target genes associated with nutrient metabolism and biochemical pathways were measured via RT-qPCR. The mRNA abundance of genes associated with amino acid (AA) transport (SLC7A8, SLC43A2), carnitine transport (SLC22A5), insulin signaling (IRS1), and antioxidant response (NFE2L2) had diet × time effect (p < 0.05) due to greater abundance in RPM versus CON cows, especially at 1 and 21 DIM. Members of the AA transport (SLC7A8, SLC25A29, SCL38A9), fatty acid β-oxidation (ACADVL), vitamin transport (SLC5A6, SLC19A2), mTOR pathway (AKT1 and mTOR), antioxidant response (KEAP1, CUL3), CDP-Choline pathway and arginine metabolism had overall greater abundance (p < 0.05) in RPM versus CON cows. Overall, data indicate that RPM can alter nutrient metabolism in the skeletal muscle around parturition partly through alterations in mRNA abundance.

Nutritional Modulation, Gut, and Omics Crosstalk in Ruminants

Simple Summary

Over the last decade, animal nutrition science has been significantly developed, supported by the great advancements in molecular technologies. For scientists, the present "feedomics and nutrigenomics" era continues to evolve and shape how research is designed, performed, and understood. The new omics interpretations have established a new point of view for the nutrition–gene interaction, integrating more comprehensive findings from animal physiology, molecular genetics, and biochemistry. In the ruminant model, this modern approach addresses rumen microbes as a critical intermediate that can deepen the studies of diet–gut interaction with host genomics. The present review discusses nutrigenomics’ and feedomics’ potential contribution to diminishing the knowledge gap about the DNA cellular activities of different nutrients. It also presents how nutritional management can influence the epigenetic pathway, considering the production type, life stage, and species for more sustainable ruminant nutrition strategies.

Abstract

Ruminant nutrition has significantly revolutionized a new and prodigious molecular approach in livestock sciences over the last decade. Wide-spectrum advances in DNA and RNA technologies and analysis have produced a wealth of data that have shifted the research threshold scheme to a more affluent level. Recently, the published literature has pointed out the nutrient roles in different cellular genomic alterations among different ruminant species, besides the interactions with other factors, such as age, type, and breed. Additionally, it has addressed rumen microbes within the gut health and productivity context, which has made interpreting homogenous evidence more complicated. As a more systematic approach, nutrigenomics can identify how genomics interacts with nutrition and other variables linked to animal performance. Such findings should contribute to crystallizing powerful interpretations correlating feeding management with ruminant production and health through genomics. This review will present a road-mapping discussion of promising trends in ruminant nutrigenomics as a reference for phenotype expression through multi-level omics changes.

Transcriptome Analysis of Bovine Rumen Tissue in Three Developmental Stages

Rumen development is a crucial physiological challenge for ruminants. However, the molecular mechanism regulating rumen development has not been clearly elucidated. In this study, we investigated genes involved in rumen development in 13 rumen tissues from three developmental stages (birth, youth, and adult) using RNA sequencing. We identified that 6,048 genes were differentially expressed among three developmental stages. Using weighted correlation network analysis, we found that 12 modules were significantly associated with developmental stages. Functional annotation and protein–protein interaction (PPI) network analysis revealed that CCNB1, CCNB2, IGF1, IGF2, HMGCL, BDH1, ACAT1, HMGCS2, and CREBBP involved in rumen development. Integrated transcriptome with GWAS information of carcass weight (CW), stomach weight (SW), marbling score (MS), backfat thickness (BFT), ribeye area (REA), and lean meat weight (LMW), we found that upregulated DEGs (fold change 0∼1) in birth–youth comparison were significantly enriched with GWAS signals of MS, downregulated DEGs (fold change >3) were significantly enriched with GWAS signals of SW, and fold change 0∼1 up/downregulated DEGs in birth–adult comparison were significantly enriched with GWAS signals of CW, LMW, REA, and BFT. Furthermore, we found that GWAS signals for CW, LMW, and REA were enriched in turquoise module, and GWAS signals for CW was enriched in lightgreen module. Our study provides novel insights into the molecular mechanism underlying rumen development in cattle and highlights an integrative analysis for illustrating the genetic architecture of beef complex traits.

Proteomic identification of ruminal epithelial protein expression profiles in response to starter feed supplementation in pre-weaned lambs

The present study aimed to comparatively characterize the ruminal epithelial protein expression profiles in lambs fed ewe milk or milk plus starter diet using proteome analysis. Twenty new-born lambs were randomly divided into a group receiving ewe milk (M, n = 10) and a group receiving milk plus starter diet (M + S, n = 10). From 10 d old, M group lambs remained with the ewe and suckled ewe milk without receiving the starter diet. The lambs in the M + S group were separated from the ewe and received starter feed. All lambs were slaughtered at 56 d old. Eight rumen epithelia samples (4 per group) were collected to characterize their protein expression profiles using proteomic technology. Proteome analysis showed that 31 upregulated proteins and 40 downregulated proteins were identified in the rumen epithelium of lambs in response to starter diet supplementation. The results showed that starter feeding regulates a variety of biological processes in the epithelium, especially blood vessel development and extracellular matrix protein expression. Meanwhile, the expression of proteins associated with synthesis and degradation of ketone bodies, butanoate metabolism, and citrate cycle signaling transduction pathway were upregulated in the group with starter diet supplementation, including 3-hydroxy-3-methylglutaryl coenzyme A synthase (HMGCS2, fold change [FC] = 1.93), 3-hydroxybutyrate dehydrogenase 1 (BDH1, FC = 1.91), and isocitrate dehydrogenase 1 (IDH1, FC = 8.12). The metabolic processes associated with ammonia detoxification and antioxidant stress were also affected by starter diet supplementation, with proteins, microsomal glutathione S-transferase 3 (MGST3, FC = 2.37) and IDH1, linked to the biosynthesis of glutamate and glutathione metabolism pathway being upregulated in the group with starter diet supplementation. In addition, starter feeding decreased the expression of Ras-related protein rap-1A (RAP1A, FC = 0.48) enriched in Rap1 signaling pathway, Ras signaling pathway, cyclic adenosine monophosphate (cAMP) signaling pathway, and mitogen-activated protein kinase (MAPK) signaling pathway. In summary, starter feed supplementation changed the expression of proteins related to energy production, ammonia detoxification, antioxidant stress, and signaling pathways related to proliferation and apoptosis, which facilitates the rumen epithelia development in lambs. The results provide new insights into the molecular adaptation of rumen epithelia in response to starter diet supplementation at the protein level in lambs.

Tributyrin supplementation in pasteurized waste milk: Effects on growth performance, health, and blood parameters of dairy calves

This study evaluated the effects of incremental tributyrin supplementation in pasteurized waste milk on growth performance, health, and blood metabolism of dairy calves before and after weaning. Forty-eight newborn female Holstein dairy calves (39.6 ± 2.75 kg; mean ± standard deviation) were blocked by age and randomly assigned to 3 treatments: pasteurized waste milk (1) without supplementation, (2) with 1 g/L of tributyrin products (unprotected solid powder; containing 35% tributyrin), or (3) with 2 g/L of tributyrin products. The calves were weaned on d 56 and were raised until d 77. Data were analyzed for the preweaning, postweaning, and overall periods. The results showed that starter intake and hay intake were not different among treatments in any period of the trial, but the crude protein intake tended to increase linearly with tributyrin supplementation during the overall period. Although tributyrin supplementation had no effects on body weight during preweaning and overall periods, body weight increased linearly with tributyrin supplementation postweaning. The average daily gain tended to increase linearly during postweaning and overall periods. No effects were observed on feed efficiency in any period. A positive linear relationship between body length and tributyrin supplementation was observed during the postweaning period, but no differences were found for the other body structural measurements in any period. The results of diarrhea showed that tributyrin concentration had a negative linear relationship with diarrhea frequency during preweaning and overall periods. The rectal temperature did not differ among treatments in any period, but a treatment × week effect for rectal body temperature was observed. For blood metabolism, tributyrin supplementation had no effects on insulin, growth hormone, total protein, albumin, or globulin. No differences were found in serum amyloid A concentration in any of the periods, yet haptoglobin concentration decreased linearly with increasing tributyrin concentration during postweaning and overall periods. Endothelin concentration showed a tendency to decrease linearly during preweaning and postweaning periods and decreased linearly with tributyrin supplementation during the overall period. An increasing tributyrin concentration was associated with a negative linear relationship with IL-1β concentration during the preweaning period, and no differences were found in the other periods. The concentration of IL-6 and tumor necrosis factor α were not different among treatments in any of the periods. These data suggest that increasing the concentration of tributyrin in pasteurized waste milk could increase growth performance and health of dairy calves, and incremental tributyrin supplementation could linearly reduce haptoglobin, endothelin, and IL-1β concentrations, indicating a positive effect of tributyrin on alleviating oxidative stress and inflammatory status of dairy calves. Calves fed pasteurized waste milk supplemented with tributyrin products (containing 35% tributyrin) at 2 g/L compared with 1 g/L of milk had more improved growth and health.

Transcriptional Reprogramming in Rumen Epithelium during the Developmental Transition of Pre-Ruminant to the Ruminant in Cattle

Simple Summary

The rumen is the critical organ mediating nutrient uptake and use in cattle. Health development is essential to ensure animal feed efficiency. In this report, we present an analysis of gene expression dynamic in rumen epithelium during the transition from pre-ruminant to ruminant in cattle fed with hay or concentrated diets at weaning. The global shifts in gene expression and correlated transcription factors activities indicate transcriptional reprogramming during weaning. Transcriptional reprogramming in rumen epithelial tissue reflects critical nutrient-gene interactions occurring during the developmental progression. The results unveiled that nutrient-gene interactions compel transcriptional reprogramming. Our findings also suggest that this transcriptional reprogramming is the molecular basis of the transitional development of pre-ruminant to the ruminant in cattle.

Abstract

We present an analysis of transcriptomic dynamics in rumen epithelium of 18 Holstein calves during the transition from pre-rumination to rumination in cattle-fed hay or concentrated diets at weaning. Three calves each were euthanized at 14 and 42 d of age to exemplify preweaning, and six calves each were provided diets of either milk replacer and grass hay or calf starter to introduce weaning. The two distinct phases of rumen development and function in cattle are tightly regulated by a series of signaling events and clusters of effectors on critical pathways. The dietary shift from liquid to solid feeds prompted the shifting of gene activity. The number of differentially expressed genes increased significantly after weaning. Bioinformatic analysis revealed gene activity shifts underline the functional transitions in the ruminal epithelium and signify the transcriptomic reprogramming. Gene ontogeny (GO) term enrichment shows extensively activated biological functions of differentially expressed genes in the ruminal epithelium after weaning were predominant metabolic functions. The transcriptomic reprogramming signifies a correlation between gene activity and changes in metabolism and energy production in the rumen epithelium, which occur at weaning when transitioning from glucose use to VFA use by epithelium during the weaning.

Effects of delaying increase in milk allowance and type of gradual weaning program on performance and health of calves fed lower levels of milk

The objective of this study was to investigate the effects of delayed increase in milk allowance and type of gradual weaning program on the feed intake, health, and growth of male Holstein calves. Using a 2 × 2 factorial design, each male Holstein calf was randomly assigned to 1 of 2 milk level treatments and 1 of 2 weaning treatments upon arrival to a rearing facility. Calves were either assigned to a moderate (MM) or lower (LM) milk level treatment. All calves received the same milk program from arrival until d 12, increasing from 4 to 5 L/d (115 to 125 g/L) over the 12 d. On d 13, MM calves began receiving additional milk compared with LM calves until they were weaned, with MM offered milk increasing to a peak of 9 L/d (140 g/L). Calves on the MM treatment received a total of 35 kg of milk replacer over 45 d, compared with LM calves, who received a total of 25 kg of milk replacer over 45 d. Calves were also assigned to be weaned by either a 2-step gradual program or a 4-step gradual program. Calves assigned to the 2-step program had their milk reduced in 2 steps from d 30 to 45, and 4-step calves had their milk reduced in 4 steps from d 30 to 45. After d 46, calves received no milk but continued to be monitored until d 59. Calves had ad libitum access to water from arrival, and solid feed was offered from d 5 onward. No interactions of effects of milk level and weaning treatment were detected. By design, calves on the MM treatment consumed greater amounts of milk than LM calves in the preweaning phase from d 13 to 29 (6.1 vs. 4.8 L/d) and weaning phases from d 30 to 45 (4.7 vs. 3.2 L/d). The LM calves consumed greater amounts of solid feed than MM calves from d 22 to 29 of the preweaning phase, and from d 30 to 40 and d 43 to 45 of the weaning phase, whereas postweaning feed consumption was similar for both milk treatments. Calves in both milk treatments had similar blood β-hydroxybutyrate levels, indicating similar rumen development. Body weight and size measurements were similar between milk treatments across the study, although LM calves had a greater average daily gain than MM calves between d 38 and 46 (0.96 vs. 0.71 kg/d). Both gradual weaning treatments resulted in similar feed consumption, growth, and health parameters. Overall, the results indicate that delaying a moderate increase in milk until 12 d after arrival at a rearing facility provided no overall beneficial effect on growth or rumen development.

Effects of 2 liquid feeding rates over the first 3 months of life on whole-body energy metabolism and energy use efficiency of dairy calves up to 5 months

Intensified milk replacer (MR) feeding in calves has nutritional long-term effects and is suggested to increase milk production later in life. However, the underlying mechanisms are not completely understood. The aim of our study was to investigate whether MR feeding intensity has long-term effects on energy metabolism and energy use efficiency of dairy calves. Newborn female Holstein calves (n = 28) were randomly assigned to 2 liquid feeding groups offered daily either 10% of body weight (BW) colostrum followed by 10% of BW MR (10%-MR) or 12% of BW colostrum followed by 20% of BW MR (20%-MR). Calves were housed individually. Weaning was completed by the end of wk 12. Hay and calf starter were fed from d 1 until the end of wk 14 and 16, respectively. A total mixed ration was fed from wk 11 onward, and the metabolizable energy intake (MEI) was determined daily. Energy metabolism of calves was measured in respiratory chambers before weaning in wk 6 and 9, and after weaning in wk 14 and 22. The MEI/BW^0.75 was higher before weaning but lower during and shortly after weaning in 20%-MR calves. During the preweaning period, the 20%-MR animals had higher average daily gain, BW, back fat thickness and muscle diameter, but lower plasma β-hydroxybutyrate concentrations. The group difference in average daily gain ceased in wk 9, differences in back fat thickness and muscle diameter ceased after weaning, whereas difference in BW^0.75 persisted until wk 23. The energy conversion ratio (BW gain/MEI) was not different before weaning, but was lower during and after weaning in 20%-MR calves. The higher MEI and BW^0.75 in 20%-MR calves resulted in higher heat production (HP), as well as in higher carbohydrate oxidation (COX) and fat oxidation during the preweaning period. Gas exchange variables normalized to BW^0.75 or MEI differed between groups only during preweaning. The energy balance was lower in 10%-MR calves in wk 6 and 9. The HP/BW^0.75 and COX/BW^0.75 were higher, whereas HP/MEI was lower in 20%-MR calves in wk 6. When normalized to BW^0.75 and MEI, HP in wk 6 and 9, and COX in wk 9 was lower in 20%-MR calves. In conclusion, 20%-MR calves showed greater efficiency estimates preweaning, but this effect did not occur after weaning, suggesting that energy use efficiency does not persist until later stages in life.

Sodium Butyrate More Effectively Mitigates the Negative Effects of High-Concentrate Diet in Dairy Cows than Sodium β-Hydroxybutyrate via Reducing Free Bacterial Cell Wall Components in Rumen Fluid and Plasma

The present study was aimed at investigating the effects of sodium butyrate and sodium β-hydroxybutyrate on lactation and health of dairy cows fed a high-concentrate (HC) diet. Eighty mid-lactation dairy cows with an average milk yield of 33.75 ± 5.22 kg/d were randomly allocated to four groups (n = 20 per group) and were fed either a low-concentrate (LC) diet, a HC diet, the HC diet with 1% sodium butyrate (HCSB), or the HC diet with 1% sodium β-hydroxybutyrate (HCHB). The feeding trial lasted for 7 weeks, with a 2-week adaptation period and a 5-week measurement period, and the trial started from 96 ± 13 d in milk. Sodium butyrate supplementation delayed the decline in milk production and improved milk synthesis efficiency and milk fat content. Additionally, it decreased the proinflammatory cytokines and acute phase proteins (APPs) in plasma, the leucocytes in blood, the somatic cell count (SCC) in milk, and the gene expression of pattern recognition receptors (PRRs) and proinflammatory cytokines in the mammary gland, due to decreasing the contents of bacterial cell wall components (lipopolysaccharide, LPS; peptidoglycan, PGN; and lipoteichoic acid, LTA) in the rumen and plasma, compared with the HC diet. Sodium β-hydroxybutyrate supplementation also improved milk yield, milk synthesis efficiency and milk fat content and partially reduced the adverse effects caused by the HC diet, but it had no effect on decreasing bacterial cell wall components in the rumen and plasma, compared with the HC diet. Collectively, both sodium butyrate and sodium β-hydroxybutyrate mitigated the negative effects of HC diet on lactation and health of dairy cows, with sodium butyrate being more effective than sodium β-hydroxybutyrate.

Transcriptomic analysis reveals the molecular mechanisms of rumen wall morphological and functional development induced by different solid diet introduction in a lamb model

Background

This study aimed to elucidate the molecular mechanisms of solid diet introduction initiating the cellular growth and maturation of rumen tissues and characterize the shared and unique biological processes upon different solid diet regimes.

Methods

Twenty-four Hu lambs were randomly allocated to three groups fed following diets: goat milk powder only (M, n = 8), goat milk powder + alfalfa hay (MH, n = 8), and goat milk powder + concentrate starter (MC, n = 8). At 42 days of age, the lambs were slaughtered. Ruminal fluid sample was collected for analysis of concentration of volatile fatty acid (VFA) and microbial crude protein (MCP). The sample of the rumen wall from the ventral sac was collected for analysis of rumen papilla morphology and transcriptomics.

Results

Compared with the M group, MH and MC group had a higher concentration of VFA, MCP, rumen weight, and rumen papilla area. The transcriptomic results of rumen wall showed that there were 312 shared differentially expressed genes (DEGs) between in “MH vs. M” and “MC vs. M”, and 232 or 796 unique DEGs observed in “MH vs. M” or “MC vs. M”, respectively. The shared DEGs were most enriched in VFA absorption and metabolism, such as peroxisome proliferator-activated receptor (PPAR) signaling pathway, butanoate metabolism, and synthesis and degradation of ketone bodies. Additionally, a weighted gene co-expression network analysis identified M16 (2,052 genes) and M18 (579 genes) modules were positively correlated with VFA and rumen wall morphology. The M16 module was mainly related to metabolism pathway, while the M18 module was mainly associated with signaling transport. Moreover, hay specifically depressed expression of genes involved in cytokine production, immune response, and immunocyte activation, and concentrate starter mainly altered nutrient transport and metabolism, especially ion transport, amino acid, and fatty acid metabolism.

Conclusions

The energy production during VFA metabolism may drive the rumen wall development directly. The hay introduction facilitated establishment of immune function, while the concentrate starter enhanced nutrient transport and metabolism, which are important biological processes required for rumen development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-021-00556-4.

Influence of a Polyherbal Mixture in Dairy Calves: Growth Performance and Gene Expression

A polyherbal feed mixture containing (Achyrantes aspera, Trachyspermum ammi, Citrullus colocynthis, Andrographis paniculata, and Azadirachta indica) was evaluated in growing calves through blood chemistry, blood biometry, and gene expression during the pre-ruminant to weaning period. Forty Holstein calves (initial BW 45.6 ± 3.2 kg; 22.8 ± 0.9 days post birth) from a dairy farm were randomly assigned to the following treatments: 0, 3, 4, and 5 g/d of a polyherbal mixture, dosed in colloid gels with gelatin. Calves were housed in individual outdoor boxes with ad libitum access to a 21.5% CP calf starter and water and fed individually with a mixture of milk and a non-medicated milk replacer (22% CP). Blood samples were collected on day 59 for blood chemistry, blood biometry, and gene expression analysis in leukocyte through microarray assays. Immunoglobulins were quantified by enzyme-linked immunosorbent assay. The animals treated with the polyherbal mixture showed a quadratic effect on final body weight, daily weight gain, final hip height, and final thoracic girth. The best performance results were obtained with a treatment dose of 4 g/d. The serum IgG increased linearly with the treatment doses. Gene set enrichment analysis of upregulated genes revealed that the three biological processes with higher fold change were tight junction, mucin type O-Glycan biosynthesis, and intestinal immune network for IgA production. Also, these upregulated genes influenced arachidonic acid metabolism, and pantothenate and CoA biosynthesis. Gene ontology enrichment analysis indicated that the pathways enriched were PELP1 estrogen receptor interacting protein pathways, nuclear receptors in lipid metabolism and toxicity, tight junction, ECM-receptor interaction, thyroid hormone signaling pathways, vascular smooth muscle contraction, ribosome function, glutamatergic synapse pathway, focal adhesion, Hippo, calcium, and MAPK signaling pathways.

Influence of starter crude protein content on growth and body composition of dairy calves in an enhanced early nutrition program

Our objectives were to determine the effect of starter crude protein (CP) content on body composition of male Holstein calves from birth to 10 wk of age in an enhanced early nutrition program, and to compare the enhanced program to a conventional milk replacer program. Calves (n = 45) were purchased on the day of birth and assigned to a randomized block design. Eight calves were harvested at baseline and remaining calves were divided among the following 3 dietary treatments: (1) low rate of milk replacer [LMR; 20.6% CP, 21.7% fat; 1.25% of body weight (BW) as dry matter (DM)] plus conventional starter (CCS; 21.5% CP, DM basis); n = 11 calves; (2) high rate of milk replacer (HMR; 29.1% CP, 17.3% fat; 1.5% of BW as DM for wk 1, 2% of BW as DM wk 2-5, 1% of BW as DM wk 6) plus conventional starter; n = 12 calves; and (3) enhanced milk replacer (HMR) plus high-CP starter (HCS; 26% CP, DM basis); n = 14 calves. A subset of calves (n = 8) was harvested on d 2 to provide baseline data. Calves began treatments on d 2 or 3 of age. Calves were weaned at d 42. Starter was available ad libitum. Calves from each treatment were harvested at 5 (n = 18) and 10 (n = 19) wk of age and divided into 4 fractions: carcass; viscera; blood; and head, hide, feet, and tail. Fractions were analyzed for energy, CP, lipid, and ash. Average weekly starter intake did not differ between enhanced treatments. Gain of BW was greater for calves fed HMR than for LMR, but was unaffected by starter CP. Carcass weights at 5 wk were greater for HMR but did not differ between starter CP content. At 10 wk, carcass weights were heavier for HMR and had a greater percentage of empty BW for HMR + CCS than for HMR + HCS. At 10 wk, the weights of reticulorumen and liver were greater for calves fed HMR + HCS than for those fed HMR + CCS. At 5 wk, empty BW gain for HMR contained more water and less fat and ash than in calves fed LMR. At 10 wk, empty BW gain for calves fed HMR + HCS contained a greater percentage of water and less fat than for calves fed HMR + CCS. Plasma β-hydroxybutyrate was greater after weaning for calves fed HMR + HCS than for those fed HMR + CCS. After weaning, calves fed HMR had greater plasma total protein concentration than those fed LMR, and total protein was greater for calves fed HMR + HCS than those fed HMR + CCS. Plasma urea N was greater for calves fed HMR treatments, and postweaning was greater for calves fed HMR + HCS. A high-CP starter had minimal effect on empty BW gain before weaning, but after weaning it tended to increase mass of reticulorumen and liver.

Altitude influences microbial diversity and herbage fermentation in the rumen of yaks

BACKGROUND

Rumen microbiota in ruminants are vital for sustaining good rumen ecology, health, and productivity. Currently, limited information is available regarding the response of yaks (Bos grunniens) to fluctuating environments, especially the rumen microbiome. To address this, we investigated the diet, rumen bacterial community, and volatile fatty acids (VFA) of rumen fluid of yaks raised in the great Qinghai-Tibet plateau (QTP) at 2800 (low altitude, L), 3700 (middle altitude, M), and 4700 m (high altitude, H) above sea level.

RESULTS

The results showed that despite a partial diet overlap, H yaks harbored higher fibrous fractious contents than the M and L grazing yaks. Bacteria including Christensenellaceae_R-7_group, Ruminococcus_1, Romboutsia, Alloprevotella, Eubacterium coprostanoligenes, Clostridium, Streptococcus, and Treponema were found to be enriched in the rumen of yaks grazing at H. They also showed higher rumen microbial diversity and total VFA concentrations than those shown by yaks at M and L. Principal coordinates analysis (PCoA) on weighted UniFrac distances revealed that the bacterial community structure of rumen differed between the three altitudes. Moreover, Tax4fun metagenome estimation revealed that microbial genes associated with energy requirement and carbohydrate metabolic fate were overexpressed in the rumen microbiota of H yaks.

CONCLUSIONS

Collectively, our results revealed that H yaks had a stronger herbage fermenting ability via rumen microbial fermentation. Their enhanced ability of utilizing herbage may be partly owing to a microbiota adaptation for more energy requirements in the harsh H environment, such as lower temperature and the risk of hypoxia.

Effect of pelleted vs. ground starter with or without hay on preweaned dairy calves

The objective of this study was to evaluate the effect of the physical form of starter and inclusion of hay in the diet of preweaning dairy calves on performance, digestibility, ruminal development, and mRNA expression of genes involved in ruminal metabolism. Holstein × Gyr crossbred male calves (n = 38 1day old) were assigned to 3 treatments for 9 weeks: Control (n = 13; pellet starter with 4 mm diameter and 18 mm length and 4% steam-flaked corn), Ground (n = 12; same starter of the control but ground pass through a 4.0 mm sieve), or Ground plus 5% chopped Tifton hay GH (n = 13). All calves were fed 4 L/d of whole milk up to 63 d of age and were abruptly weaned at 64 d of age. Water and diets were offered ad libitum. Samples of ruminal contents were obtained from all animals at 30, 45, and 60 d of age to evaluate pH, ammonia nitrogen, and volatile fatty acids (VFA). At 55 d of age, an apparent digestibility assay was performed using 18 animals (n = 6/ treatment). At 65 d of age, the 18 animals were euthanized to evaluate the development of the digestive tract. The physical form of starter and the dietary inclusion of hay did not influence starter intake (Control 326 g/d, Ground 314 g/d and GH 365 g/d), daily weight gain (Control 541g/d, Ground 531g/d and GH 606g/d), feed efficiency, apparent nutrient digestibility, energy partitioning, nitrogen balance, ruminal pH, ammonia nitrogen concentration, VFA, the development of the digestive tract and the mRNA expression of genes involved in AGV metabolism.

Review: Importance of colostrum supply and milk feeding intensity on gastrointestinal and systemic development in calves

Feeding management of the postnatal and preweaning calf has an important impact on calf growth and development during this critical period and affects the health and well-being of the calves. After birth, an immediate and sufficient colostrum supply is a prerequisite for successful calf rearing. Colostrum provides high amounts of nutrient as well as non-nutrient factors that promote the immune system and intestinal maturation of the calf. The maturation and function of the neonatal intestine enable the calf to digest and absorb the nutrients provided by colostrum and milk. Therefore, colostrum intake supports the start of anabolic processes in several tissues, stimulating postnatal body growth and organ development. After the colostrum feeding period, an intensive milk feeding protocol, that is, at least 20% of BW milk intake/day, is required to realise the calf potential for growth and organ development during the preweaning period. Insufficient milk intake delays postnatal growth and may have detrimental effects on organ development, for example, the intestine and the mammary gland. The somatotropic axis as the main postnatal endocrine regulatory system for body growth is stimulated by the intake of high amounts of colostrum and milk and indicates the promotion of anabolic metabolism in calves. The development of the forestomach is an important issue during the preweaning period in calves, and forestomach maturation is best achieved by solid feed intake. Unfortunately, intensive milk-feeding programmes compromise solid feed intake during the first weeks of life. In the more natural situation for beef calves, when milk and solid feed intake occurs at the same time, calves benefit from the high milk intake as evidenced by enhanced body growth and organ maturation without impaired forestomach development during weaning. To realise an intensive milk-feeding programme, it is recommended that the weaning process should not start too early and that solid feed intake should be at a high extent despite intensive milk feeding. A feeding concept based on intensive milk feeding prevents hunger and abnormal behaviour of the calves and fits the principles of animal welfare during preweaning calf rearing. Studies on milk performance in dairy cows indicate that feeding management during early calf rearing influences lifetime performance. Therefore, an intensive milk-feeding programme affects immediate as well as long-term performance, probably by programming metabolic pathways during the preweaning period.

Diversity and Composition of Rumen Bacteria, Fungi, and Protozoa in Goats and Sheep Living in the Same High-Altitude Pasture

Simple Summary

Tibetan goats and sheep graze together but have different growth performances, immune responses, and feeding preferences in the Tibetan pasture. Rumen microbiota composed of bacteria, fungi, and protozoa are necessary for a healthy ruminant. Therefore, in this study, we comprehensively describe composition and diversity of bacteria, fungi, and protozoa in the high- altitude rumen. Compared with sheep, the bacteria that degrade crude protein and produce volatile fatty acids (VFA) were increased in the rumen of goats (Saccharofermentans and Lachnospiraceae_XPB1014) (p < 0.05). In addition, when compared with goats, the fungi and protozoa that degrade fiber were increased in rumen of sheep (Neocallimastigaceae and Metadinium) (p < 0.05). Furthermore, VFA were significantly increased in the rumen of goats compared with sheep (p < 0.05). The VFA level was consistent with differences in the microbiota composition in the rumen between goats and sheep. Under mixed grazing conditions, goats tend to select a high-crude protein diet that is good for growth, whereas sheep tend to select a high-lignin diet that is difficult to digest. Therefore, the different microbiota in the rumen of goats and sheep may be explained by dietary preference.

Abstract

Environmental adaptation of ruminants was highly related to microbiota in the rumen. To investigate the diversity and composition of bacteria, fungi, and protozoa in the rumen of high-altitude animals, amplicon gene sequencing was performed using rumen fluid samples derived from both Tibetan goats and sheep at the same pasture in a highland (altitude > 4800 m). Between these two species, the ruminal bacteria and fungi were significantly different at multiple taxonomic levels. The alpha diversity of bacteria was significantly high in goats (p < 0.05). One hundred and sixty-four and 29 Operational Taxonomy Units (OTUs) with significant differences were detected in bacteria and fungi, respectively. The abundance of bacteria, fungi, and protozoa in the rumen was characterized at multiple taxonomic levels, and we determined that Firmicutes, Bacteroidetes, Neocallimastigomycota, and Ciliophora were the most abundant bacteria, fungi, and protozoa. The family Neocallimastigaceae and the genus Metadinium had cellulose degradation capacity in the rumen with high abundance, thereby, suggesting that fungi and protozoa played an essential role in rumen fermentation. In addition, by comparing microbiota in the rumen of goats and sheep it was found, that the fiber-degrading fungi genus (Cyllamyces) was increased in the rumen of sheep (p < 0.05) whereas VFA-producing bacteria (Saccharofermentans and Lachnospiraceae_XPB1014) were increased in the rumen of goats (p < 0.05). Interestingly, in the rumen, no differences in protozoa were observed between goats and sheep (p > 0.05). Furthermore, when compared to sheep, level of acetic acid, propionic acid, and total volatile fatty acid (TVFA) were significantly increased in the rumen of goats (p < 0.05). Taken together, these results suggested microbiota in the rumen drive goats to better adapt to high-altitude grazing conditions.

A novel duplicated insertion/deletion (InDel) of the CPT1a gene and its effects on growth traits in goat

Carnitine palmitoyltransferase 1a (CPT1a) is a rate-limited enzyme in the mitochondrial fatty acid β-oxidation pathway. It acts as a bridge between PPARα and the fatty acid oxidation pathways and is closely related to ruminant growth and development. In this study, one 12 bp InDel polymorphism of the CPT1a gene was identified in 700 goats, and we designated these three genotypes II, ID, and DD. Association analysis showed that the InDel polymorphism was closely associated with trunk index (p = 0.008) and body length index (p = 0.034) in Hainan black goats, and body length (p = 0.010), chest circumference (p = 0.004), chest depth (p = 0.029), and huckle bone width (p = 0.002) in Nubian goats, as well as the chest circumference (p = 0.016) in the Fuqing goat breed. In both kids and adult goats, qRT-PCR results showed that the CPT1a gene was expressed in all tissues, showing the highest mRNA levels in the liver, lung, spleen, and kidney, followed by the adipose tissue and brain. This indicates an association between the InDel of the CPT1a gene and growth traits in selected goat breeds, which may facilitate marker-assisted selection in goat genetics and breeding.

Impact of weaning age on rumen development in artificially reared lambs1

This study examined the impact of weaning age (4 vs. 6 wk) on rumen morphological and metabolic development in artificially reared lambs. Thirty-two mixed-sex lambs (2 to 5 d old) were randomly allocated to 1 of 2 weaning groups: early weaning (EW; 4 wk) and control (Ctrl; 6 wk). Lambs were individually penned and fed milk replacer (MR; 24% CP and 25% fat, DM basis) at 20% of their corresponding initial BW. Weaning was achieved by gradual reduction of MR allowance over a period of 3 wk using a step-down procedure. Concentrate and meadow hay were offered ad libitum from 1 d of the study until 6 wk, when lambs were transferred to a mixed sward pasture. At week 4, individual DMI were recorded and blood samples collected to measure β-hydroxybutyrate (BHBA) and NEFA. Eight animals per group were euthanized at week 4 and 16 to evaluate short chain fatty acids (SCFA) and histomorphometry of the rumen walls: dorsal (DS), ventral (VS), dorsal blind (DBS), and ventral blind (VBS) sacs. Linear mixed models were used to analyze the effect of weaning treatments at week 4 and 16, and to compare between timepoints and between rumen sites. Dry matter intake and rumen SCFA profiles were similar between groups (P > 0.10) at week 4 and 16. Plasma concentrations of BHBA were greater (P = 0.03) in EW than in Ctrl lambs, while NEFA did not differ (P > 0.10) between groups at week 4. No effect of weaning age on rumen empty weight, and papillae density, length, width, surface area ratio, and muscle layer thickness at any of the 4 rumen sites was found (P > 0.10) at either week 4 or week 16, except for greater (P = 0.02) papillae epithelium thickness in the DBS at week 4 in EW than Ctrl lambs. Papillae morphology and muscular thickness differed across rumen sites at week 4 and week 16 (P < 0.05), except for papillae density and surface area ratio at 4 week (P > 0.10). Rumen papillae length, width, and muscle layer thickness increased while papillae density and surface area ratio decreased (P < 0.05) between 4 and 16 wk. The results of this study indicate that morphological and physiological development of the rumen can be accelerated to support weaning of artificially reared lambs at 4 wk, using a step-down weaning system. Morphological differences between rumen sacs denote that future studies in lambs evaluating the impact of different diets should involve representative sampling across the rumen rather than a single site to more accurately study rumen development and ontogenic changes.

Jersey steer ruminal papillae histology and nutrigenomics with diet changes

The transition from a high forage to a high concentrate diet is an important milestone for beef cattle moving from a stocker system to the feedlot. However, little is known about how this transition affects the rumen epithelial gene expression. This study assessed the effects of the transition from a high forage to a high concentrate diet as well as the transition from a high concentrate to a high forage diet on a variety of genes as well as ruminal papillae morphology in rumen fistulated Jersey steers. Jersey steers (n = 5) were fed either a high forage diet (80% forage and 20% grain) and transitioned to a high concentrate diet (20% forage and 80% grain) or a high concentrate diet (40% forage and 60% grain) and transitioned to a high forage diet (100% forage). Papillae from the rumen were collected for histology and RT‐qPCR analysis. Body weight had a tendency for significant difference (p = .08). Histological analysis did not show changes in papillae length or width in steers transitioning from a high forage to a high concentrate diet or vice versa (p > .05). Genes related to cell membrane structure (CLDN1, CLDN4, DSG1), fatty acid metabolism (CPT1A, ACADSB), glycolysis (PFKL), ketogenesis (HMGCL, HMGCS2, ACAT1), lactate/pyruvate (LDHA), oxidative stress (NQO1), tissue growth (AKT3, EGFR, EREG, IGFBP5, IRS1) and the urea cycle (SLC14A1) were considered in this study. Overall, genes related to fatty acid metabolism (ACADSB) and growth and development (AKT3 and IGFBP5) had a tendency for a treatment × day on trial interaction effect. These profiles may be indicators of rumen epithelial adaptations in response to changes in diet. In conclusion, these results indicate that changes in the composition of the diet can alter the expression of genes with specific functions in rumen epithelial metabolism.

Review of Strategies to Promote Rumen Development in Calves

Simple Summary

The rumen is an important digestive organ that plays a key role in the growth, production performance and health of ruminants. Promoting rumen development has always been a key target of calf nutrition. Current research reveals that an early feeding regime and nutrition have effects on rumen development and the establishment of rumen microbiota. The effects may persist for a long time, and consequently, impact the lifetime productive performance and health of adult ruminants. The most sensitive window for rumen manipulation may exist in the postnatal and weaning period. Thus, the early feeding regime and nutrition of calves deserve further research. The establishment of the rumen bacterial community is a mysterious and complex process. The development of microbial 16S rDNA gene sequencing and metagenome analysis enables us to learn more about the establishment of rumen microbes and their interactions in host gastrointestinal (GI) tract development.

Abstract

Digestive tract development in calves presents a uniquely organized system. Specifically, as the rumen develops and becomes colonized by microorganisms, a calf physiologically transitions from a pseudo-monogastric animal to a functioning ruminant. Importantly, the development of rumen in calves can directly affect the intake of feed, nutrient digestibility and overall growth. Even minor changes in the early feeding regime and nutrition can drastically influence rumen development, resulting in long-term effects on growth, health, and milk yields in adult cattle. Rumen development in newborn calves is one of the most important and interesting areas of calf nutrition. This paper presents a comprehensive review of recent studies of the gastrointestinal (GI) tract development in calves. Moreover, we also describe the effect of the environment in shaping the GI tract, including diet, feed additives and feeding management, as well as discuss the strategies to promote the physiological and microbiological development of rumen.

Genome-wide association analysis for β-hydroxybutyrate concentration in Milk in Holstein dairy cattle

BACKGROUND

Ketosis in dairy cattle has been shown to cause a high morbidity in the farm and substantial financial losses to dairy farmers. Ketosis symptoms, however, are difficult to identify, therefore, the amount of ketone bodies (mainly β-hydroxybutyric acid, BHB) is used as an indicator of subclinical ketosis in cows. It has also been shown that milk BHB concentrations have a strong correlation with ketosis in dairy cattle. Mid-infrared spectroscopy (MIR) has recently became a fast, cheap and high-throughput method for analyzing milk components. The aim of this study was to perform a genome-wide association study (GWAS) on the MIR-predicted milk BHB to identify genomic regions, genes and pathways potentially affecting subclinical ketosis in North American Holstein dairy cattle.

RESULTS

Several significant regions were identified associated with MIR-predicted milk BHB concentrations (indicator of subclinical ketosis) in the first lactation (SCK1) and second and later lactations (SCK2) in Holstein dairy cows. The strongest association was located on BTA6 for SCK1 and BTA14 on SCK2. Several SNPs on BTA6 were identified in regions and variants reported previously to be associated with susceptibility to ketosis and clinical mastitis in Jersey and Holstein dairy cattle, respectively. One highly significant SNP on BTA14 was found within the DGAT1 gene with known functions on fat metabolism and inflammatory response in dairy cattle. A region on BTA6 and three SNPs on BTA20 were found to overlap between SCK1 and SCK2. However, a novel region on BTA20 (55-63 Mb) for SCK2 was also identified, which was not reported in previous association studies. Enrichment analysis of the list of candidate genes within the identified regions for MIR-predicted milk BHB concentrations yielded molecular functions and biological processes that may be involved in the inflammatory response and lipid metabolism in dairy cattle.

CONCLUSIONS

The results of this study confirmed several SNPs and genes identified in previous studies as associated with ketosis susceptibility and immune response, and also found a novel region that can be used for further analysis to identify causal variations and key regulatory genes that affect clinical/ subclinical ketosis.

Comparative transcriptome analysis of rumen papillae in suckling and weaned Japanese Black calves using RNA sequencing

The length and density of rumen papillae starts to increase during weaning and growth of ruminants. This significant development increases the intraruminal surface area and the efficiency of VFA (acetate, propionate, butyrate, etc.) uptake. Thus, it is important to investigate the factors controlling the growth and development of rumen papillae during weaning. This study aimed to compare the transcriptomes of rumen papillae in suckling and weaned calves. Total RNA was extracted from the rumen papillae of 10 male Japanese Black calves (5 suckling calves, 5 wk old; 5 weaned calves, 15 wk old) and used in RNA-sequencing. Transcript abundance was estimated and differentially expressed genes were identified and these data were then used in Ingenuity Pathway Analysis (IPA) to predict the major canonical pathways and upstream regulators. Among the 871 differentially expressed genes screened by IPA, 466 genes were upregulated and 405 were downregulated in the weaned group. Canonical pathway analysis showed that "atherosclerosis" was the most significant pathway, and "tretinoin," a derivative of vitamin A, was predicted as the most active upstream regulator during weaning. Analyses also predicted IgG, lipopolysaccharides, and tumor-necrosis factor-α as regulators of the microbe-epithelium interaction that activates rumen-related immune responses. The functional category and the up-regulators found in this study provide a valuable resource for studying new candidate genes related to the proliferation and development of rumen papillae from suckling to weaning Japanese Black calves.

Residual feed intake in beef cattle and its association with carcass traits, ruminal solid-fraction bacteria, and epithelium gene expression

Background

Residual feed intake (RFI) describes an animal’s feed efficiency independent of growth performance. The objective of this study was to determine differences in growth performance, carcass traits, major bacteria attached to ruminal solids-fraction, and ruminal epithelium gene expression between the most-efficient and the least-efficient beef cattle. One-hundred and forty-nine Red Angus cattle were allocated to three contemporary groups according to sex and herd origin. Animals were fed a finishing diet in confinement for 70 d to determine the RFI category for each. Within each group, the two most-efficient (n = 6; RFI coefficient = − 2.69 ± 0.58 kg dry matter intake (DMI)/d) and the two least-efficient animals (n = 6; RFI coefficient = 3.08 ± 0.55 kg DMI/d) were selected. Immediately after slaughter, ruminal solids-fraction and ruminal epithelium were collected for bacteria relative abundance and epithelial gene expression analyses, respectively, using real-time PCR.

Results

The most-efficient animals consumed less feed (P = 0.01; 5.03 kg less DMI/d) compared with the least-efficient animals. No differences (P > 0.10) in initial body weight (BW), final BW, and average daily gain (ADG) were observed between the two RFI classes. There were no significant RFI × sex effects (P > 0.10) on growth performance. Compared with the least-efficient group, hot carcass weight (HCW), ribeye area (REA), and kidney, pelvic, and heart fat (KPH) were greater (P ≤ 0.05) in the most-efficient cattle. No RFI × sex effect (P > 0.10) for carcass traits was detected between RFI groups. Of the 10 bacterial species evaluated, the most-efficient compared with least efficient cattle had greater (P ≤ 0.05) relative abundance of Eubacterium ruminantium, Fibrobacter succinogenes, and Megasphaera elsdenii, and lower (P ≤ 0.05) Succinimonas amylolytica and total bacterial density. No RFI × sex effect on ruminal bacteria was detected between RFI groups. Of the 34 genes evaluated in ruminal epithelium, the most-efficient cattle had greater (P ≤ 0.05) abundance of genes involved in VFA absorption, metabolism, ketogenesis, and immune/inflammation-response. The RFI × sex interactions indicated that responses in gene expression between RFI groups were due to differences in sex. Steers in the most-efficient compared with least-efficient group had greater (P ≤ 0.05) expression of SLC9A1, HIF1A, and ACO2. The most-efficient compared with least-efficient heifers had greater (P ≤ 0.05) mRNA expression of BDH1 and lower expression (P ≤ 0.05) of SLC9A2 and PDHA1.

Conclusions

The present study revealed that greater feed efficiency in beef cattle is associated with differences in bacterial species and transcriptional adaptations in the ruminal epithelium that might enhance nutrient delivery and utilization by tissues. The lack of RFI × sex interaction for growth performance and carcass traits indicates that sex may not play a major role in improving these phenotypes in superior RFI beef cattle. However, it is important to note that this result should not be considered a solid biomarker of efficient beef cattle prior to further examination due to the limited number of heifers compared with steers used in the study.

Electronic supplementary material

The online version of this article (10.1186/s40104-018-0283-8) contains supplementary material, which is available to authorized users.

Effects of Intravenous Infusion With Sodium Butyrate on Colonic Microbiota, Intestinal Development- and Mucosal Immune-Related Gene Expression in Normal Growing Pigs

This study aimed to investigate effects of intravenous infusion with sodium butyrate (SB) on colonic microbiota, intestinal mucosal immune and intestinal development in normal growing pigs. Twelve crossbred barrows (Duroc × Landrace × Large White) fitted with a medical polyethylene cannula via internal jugular vein were daily infused with 10 ml SB (200 mmol/l) or the same volume of physiological saline for 7 days. Results showed that SB infusion had no effects on the short-chain fatty acids concentrations and the number of total bacteria, but significantly increased the microbial richness estimators (ACE and Chao1), and the abundance of genera related to Clostridiales order in the colonic digesta (P < 0.05). SB infusion significantly up-regulated the mRNA expression of monocarboxylate transporter 1 (MCT1) in the colon, while no change was found in the ileum. Only the relative mRNA of pro-inflammatory cytokine IL-6 gene was decreased significantly in the ileum by SB infusion. On the contrary, in the colon, SB infusion significantly decreased the gene expression of histone deacetylase 1 (HDAC1) and pro-inflammatory cytokines IL-6, IL-18, IL-12p40, and TNF-α (P < 0.05), but significantly increased the secretory immunoglobulin A (sIgA) concentration, the gene expression of anti-inflammatory cytokine IL-10, and the expression of intestinal development-related gene zonula occludens-1 (ZO-1), occludin, and epidermal growth factor (EGF) (P < 0.05). The results suggest that systemic SB can modify colonic microbial composition, regulate the inflammatory cytokine- and intestinal development-related gene expression in pigs under the normal physiological condition. This study may provide an alternative strategy for improving the intestinal health of normal piglets.

Methionine supply alters mammary gland antioxidant gene networks via phosphorylation of nuclear factor erythroid 2-like 2 (NFE2L2) protein in dairy cows during the periparturient period

The periparturient period is the most critical period during the lactation cycle of dairy cows and is characterized by increased oxidative stress status. The objective of this experiment was to evaluate the effect of supplementing rumen-protected methionine on nuclear factor erythroid 2-like 2 (NFE2L2, formerly NRF2) protein and target gene expression in the mammary gland during the early postpartal period. Multiparous Holstein cows were used in a block design experiment with 30 cows per treatment. Treatments consisting of a basal control diet (control) or the basal diet plus rumen-protected methionine (methionine) were fed from d -28 to 60 relative to parturition. Mammary tissue biopsies were harvested on d 21 postpartum from 5 cows per treatment. Compared with control, methionine increased dry matter intake, milk yield, and milk protein content. Among plasma parameters measured, methionine led to greater methionine and lower reactive oxygen metabolites. Compared with control, methionine supply resulted in greater mRNA abundance of the NFE2L2 target genes glutamate-cysteine ligase catalytic subunit (GCLC), glutamate-cysteine ligase modifier subunit (GCLM), glutathione reductase (GSR), glutathione peroxidase 1 (GPX1), malic enzyme 1 (ME1), ferrochelatase (FECH), ferritin heavy chain 1 (FTH1), and NAD(P) H quinone dehydrogenase 1 (NQO1) in the mammary tissue. In addition, methionine upregulated the mRNA abundance of NFE2L2, NFKB1, MAPK14 and downregulated KEAP1. The ratio of phosphorylated NFE2L2 to total NFE2L2 protein, and total heme oxygenase 1 (HMOX1) protein were markedly greater in response to methionine supply. In contrast, total protein abundance of Kelch-like ECH-associated protein 1 (KEAP1), which sequesters NFE2L2 in the cytosol and reduces its activity, was lower with methionine. Besides the consistent positive effect of methionine supply on systemic inflammation and oxidative stress status, the present data indicate a positive effect also on antioxidant mechanisms within the mammary gland, which are regulated, at least in part, via phosphorylation of NFE2L2 and its target genes. The exact mechanisms for these responses merit further study.

Hepatic phosphorylation status of serine/threonine kinase 1, mammalian target of rapamycin signaling proteins, and growth rate in Holstein heifer calves in response to maternal supply of methionine

The study investigated whether methionine supply during late pregnancy is associated with liver mammalian target of rapamycin (MTOR) pathway phosphorylation, plasma biomarkers, and growth in heifer calves born to cows fed a control diet (CON) or the control diet plus ethylcellulose rumen-protected methionine (MET; 0.09% of dry matter intake) for the last 28 d prepartum. Calves were fed and managed similarly during the first 56 d of age. Plasma was harvested at birth and 2, 7, 21, 42, and 50 d of age and was used for biomarker profiling. Liver biopsies were harvested at 4, 14, 28, and 50 d of age and used for protein expression. Body weight, hip height, hip width, wither height, body length, rectal temperature, fecal score, and respiratory score were measured weekly. Starter intake was measured daily, and average daily gain was calculated during the first 8 wk of age. During the first 7 wk of age, compared with calves in the CON group, calves in the MET group had greater body weight, hip height, wither height, and average daily gain despite similar daily starter intake. Concentration of methionine in plasma was lower at birth but increased markedly at 2 and 7 d of age in MET calves. Plasma insulin, glucose, free fatty acids, and hydroxybutyrate did not differ. A greater ratio of phosphorylated α-serine/threonine kinase (AKT):total AKT protein expression was detected in MET calves, namely due to differences at 4 d of age. The phosphorylated MTOR:total MTOR ratio also was greater in MET calves due to differences at 28 and 50 d (8 d postweaning). The decrease in phosphorylated MTOR:total MTOR between 14 and 28 d in CON calves agreed with the increase in phosphorylated eukaryotic translation initiation factor 4E binding protein 1 (EIF4EBP1):total EIF4EBP1 ratio during the same time frame. The overall expression of phosphorylated ribosomal protein S6 kinase B1 (RPS6KB1):total RPS6KB1 and phosphorylated eukaryotic translation elongation factor 2 (EEF2):total EEF2 was lower in MET calves. Regardless of methionine supply prepartum, there was an 11-fold temporal decrease from 4 to 50 d in phosphorylated AKT:total AKT. Similarly, regardless of methionine supply, there were overall decreases in phosphorylation ratios of AKT, MTOR, RPS6KB1, and eukaryotic translation initiation factor 2A (EIF2A) over time. Data provide evidence of a positive effect of methionine supply during the last month of pregnancy on rates of growth during the first 7 wk of age. Phosphorylation status of some components of the MTOR pathway in neonatal calf liver also was associated with greater maternal supply of methionine. Thus, the data suggest that molecular mechanisms in the liver might be programmed by supply of methionine during late pregnancy. The exact mechanisms coordinating the observed responses remain to be determined.

Skeletal muscle and liver gene expression profiles in finishing steers supplemented with Amaize

Our main objective was to evaluate the effects of feeding α-amylase (Amaize, Alltech Inc., Nicholasville, KY, USA) for 140 days on skeletal muscle and liver gene transcription in beef steers. Steers fed Amaize had lower average daily gain (p = .03) and gain:feed ratio (p = .05). No differences (p > .10) in serum metabolites or carcass traits were detected between the two groups but Amaize steers tended (p < .15) to have increased 12th rib fat depth. Microarray analysis of skeletal muscle revealed 21 differentially expressed genes (DEG), where 14 were up-regulated and seven were down-regulated in Amaize-fed steers. The bioinformatics analysis indicated that metabolic pathways involved in fat formation and deposition, stress response, and muscle function were activated, while myogenesis was inhibited in Amaize-fed steers. The quantitative PCR results for liver revealed a decrease (p < .01) in expression of fatty acid binding protein 1 (FABP1) and 3-hydroxybutyrate dehydrogenase 1 (BDH1) with Amaize. Because these genes are key for intracellular fatty acid transport, oxidation and ketone body production, data suggest a reduction in hepatic lipid catabolism. Future work to investigate potential positive effects of Amaize on cellular stress response, muscle function, and liver function in beef cattle appears warranted.

Integration of miRNA weighted gene co-expression network and miRNA-mRNA co-expression analyses reveals potential regulatory functions of miRNAs in calf rumen development

This study aimed to explore the roles of microRNAs (miRNAs) in calf rumen development during early life. Rumen tissues were collected from 16 calves (8 at pre-weaning and 8 at post-weaning) for miRNA-sequencing, differential expression (DE), miRNA weighted gene co-expression network (WGCNA) and miRNA-mRNA co-expression analyses. 295 miRNAs were identified. Bta-miR-143, miR-26a, miR-145 and miR-27b were the most abundantly expressed. 122 miRNAs were significantly DE between the pre- and post-weaning periods and the most up- and down-regulated miRNAs were bta-miR-29b and bta-miR-493, respectively. Enrichment analyses of the target genes of DE miRNAs revealed important roles for miRNA in rumen developmental processes, immune system development, protein digestion and processes related to the extracellular matrix. WGCNA indicated that bta-miR-145 and bta-miR-199a-3p are important hub miRNAs in the regulation of these processes. Therefore, bta-miR-143, miR-29b, miR-145, miR-493, miR-26a and miR-199 family members might be key regulators of calf rumen development during early life.

Effects of different amylose to amylopectin ratios on rumen fermentation and development in fattening lambs

OBJECTIVE

The objective of this experiment was to examine the effects of different amylose/amylopectin ratios on rumen fermentation and development of fattening lambs.

METHODS

Forty-eight 7-day-old male Small-tailed Han sheep×Northeast fine wool sheep were randomly assigned to four treatments of dietary amylose/amylopectin ratios (0.12, 0.23, 0.24, and 0.48 in tapioca starch, corn starch, wheat starch and pea starch diets, respectively). Three lambs from each treatment were slaughtered at 21, 35, 56, and 77 days of age to determine the rumen fermentation and development.

RESULTS

Compared with tapioca starch diet, the pea starch diet significantly increased the concentration of ammonia nitrogen in the ruminal fluid of lambs but significantly decreased the bacterial protein content. At 56 and 77 d, the rumen propionate concentration tended to be greatest in the tapioca starch group than in other groups. The rumen butyrate concentration was the greatest in lambs fed on pea starch compared with those fed on other starch diets. Furthermore, the pea starch diet significantly stimulated rumen development by increasing the papillae height, width and surface area in the rumen ventral or dorsal locations in lambs. However, different amylose/amylopectin ratios diets did not significantly affect the feed intake, body weight, average daily gain, the relative weight and capacity of the rumen in lambs with increasing length of trial periods.

CONCLUSION

Lambs early supplemented with a high amylose/amylopectin ratio diet had favourable morphological development of rumen epithelium, which was not conducive to bacterial protein synthesis.

Integration of lncRNA and mRNA Transcriptome Analyses Reveals Genes and Pathways Potentially Involved in Calf Intestinal Growth and Development during the Early Weeks of Life

A better understanding of the factors that regulate growth and immune response of the gastrointestinal tract (GIT) of calves will promote informed management practices in calf rearing. This study aimed to explore genomics (messenger RNA (mRNA)) and epigenomics (long non-coding RNA (lncRNA)) mechanisms regulating the development of the rumen and ileum in calves. Thirty-two calves (≈5-days-old) were reared for 96 days following standard procedures. Sixteen calves were humanely euthanized on experiment day 33 (D33) (pre-weaning) and another 16 on D96 (post-weaning) for collection of ileum and rumen tissues. RNA from tissues was subjected to next generation sequencing and 3310 and 4217 mRNAs were differentially expressed (DE) between D33 and D96 in ileum and rumen tissues, respectively. Gene ontology and pathways enrichment of DE genes confirmed their roles in developmental processes, immunity and lipid metabolism. A total of 1568 (63 known and 1505 novel) and 4243 (88 known and 4155 novel) lncRNAs were detected in ileum and rumen tissues, respectively. Cis target gene analysis identified BMPR1A, an important gene for a GIT disease (juvenile polyposis syndrome) in humans, as a candidate cis target gene for lncRNAs in both tissues. LncRNA cis target gene enrichment suggested that lncRNAs might regulate growth and development in both tissues as well as posttranscriptional gene silencing by RNA or microRNA processing in rumen, or disease resistance mechanisms in ileum. This study provides a catalog of bovine lncRNAs and set a baseline for exploring their functions in calf GIT development.

Effect of butyrate infusion into the rumen on butyrate flow to the duodenum, selected gene expression in the duodenum epithelium, and nutrient digestion in sheep

The aim of the study was to determine the effect of butyrate infusion into the rumen on butyrate flow to the duodenum, expression of short-chain fatty acid (SCFA) transporters (monocarboxylate transporter-1, -2, and -4) and receptors (G protein coupled receptor-41 and -43) in the duodenal epithelium and nutrient digestion in sheep. Eight wethers (39.0 ± 3.00 kg; mean ± SD) with ruminal and T-shape duodenal cannulas were allocated to 4 × 4 replicated Latin square design with each experimental period lasting for 21 d (12 d of adaptation and 9 d for data and sample collection). Experimental treatments were: 1) distilled water infusion into the rumen (CONT); 2) 15 g/d of butyric acid infusion into the rumen (BUT15); 3) 30 g/d of butyric acid infusion into the rumen (BUT30); and 4) 45 g/d of butyric acid infusion into the rumen (BUT45). The daily dose of butyrate was infused into the rumen via the rumen cannula, with 200 mL of solution of butyric acid and distilled water, at a constant rate (0.1389 mL/min) throughout the day using a peristaltic pump. Correspondingly, 200 mL/d of distilled water was infused into the rumen of CONT. The wethers were fed daily 900 g of chopped meadow hay and 200 g of concentrate in two equal meals at 0600 and 1800 h. Butyrate infusion into the rumen did not affect total SCFA concentration in the rumen fluid ( > 0.11). Molar proportion of butyrate in total SCFA linearly increased, and molar proportion of acetate and isovalerate linearly decreased ( ≤ 0.02) with an increasing amount of butyrate infused into the rumen. The molar proportion of butyrate in total SCFA in the duodenal digesta linearly increased ( < 0.01), and butyrate flow to duodenum tended to linearly increase ( = 0.06) with an increasing dose of exogenous butyrate delivered to the rumen. Butyrate infusion into the rumen did not affect ( ≥ 0.14) the mRNA expression of monocarboxylate transporter-2 and -4 and G protein coupled receptor-43 in the duodenal epithelium. The G protein coupled receptor-41 and monocarboxylate transporter-1 mRNA expression in the duodenal epithelium was very low in many of the analyzed samples. Digestibility of organic matter, neutral detergent fiber, and acid detergent fiber in the stomach (forestomach and abomasum) decreased for BUT15 and BUT30 and then increased for BUT45 (quadratic, ≤ 0.04); however, neither digestibility in the intestine nor total tract digestibility differed between treatments ( ≥ 0.10).