Combined Metabolomics and Biochemical Analyses of Serum and Milk Revealed Parity-Related Metabolic Differences in Sanhe Dairy Cattle.

The production performance of dairy cattle is closely related to their metabolic state. This study aims to provide a comprehensive understanding of the production performance and metabolic features of Sanhe dairy cattle across different parities, with a specific focus on evaluating variations in milk traits and metabolites in both milk and serum. Sanhe dairy cattle from parities 1 to 4 (S1, n = 10; S2, n = 9; S3, n = 10; and S4, n = 10) at mid-lactation were maintained under the same feeding and management conditions. The milk traits, hydrolyzed milk amino acid levels, serum biochemical parameters, and serum free amino acid levels of the Sanhe dairy cattle were determined. Multiparous Sanhe dairy cattle (S2, S3, and S4) had a greater milk protein content, lower milk lactose content, and lower solids-not-fat content than primiparous Sanhe dairy cattle (S1). Moreover, S1 had a higher ratio of essential to total amino acids (EAAs/TAAs) in both the serum and milk. The serum biochemical results showed the lower glucose and total protein levels in S1 cattle were associated with milk quality. Furthermore, ultra-high-resolution high-performance liquid chromatography with tandem MS analysis (UPLC-MS/MS) identified 86 and 105 differential metabolites in the serum and milk, respectively, and these were mainly involved in amino acid, carbohydrate, and lipid metabolism. S1 and S2/S3/S4 had significantly different metabolic patterns in the serum and milk, and more vitamin B-related metabolites were significantly higher identified in S1 than in multiparous cattle. Among 36 shared differential metabolites in the serum and milk, 10 and 7 metabolites were significantly and strongly correlated with differential physiological indices, respectively. The differential metabolites identified were enriched in key metabolic pathways, illustrating the metabolic characteristics of the serum and milk from Sanhe dairy cattle of different parities. L-phenylalanine, dehydroepiandrosterone, and linoleic acid in the milk and N-acetylornithine in the serum could be used as potential marker metabolites to distinguish between Sanhe dairy cattle with parities of 1-4. In addition, a metabolic map of the serum and milk from the three aspects of carbohydrates, amino acids, and lipids was created for the further analysis and exploration of their relationships. These results reveal significant variations in milk traits and metabolites across different parities of Sanhe dairy cattle, highlighting the influence of parity on the metabolic profiles and production performance. Tailored nutritional strategies based on parity-specific metabolic profiles are recommended to optimize milk production and quality in Sanhe cattle.

Hesperidin ameliorates H2O2-induced bovine mammary epithelial cell oxidative stress via the Nrf2 signaling pathway.

BACKGROUND: Hesperidin is a citrus flavonoid with anti-inflammatory and antioxidant potential. However, its protective effects on bovine mammary epithelial cells (bMECs) exposed to oxidative stress have not been elucidated. RESULTS: In this study, we investigated the effects of hesperidin on H2O2-induced oxidative stress in bMECs and the underlying molecular mechanism. We found that hesperidin attenuated H2O2-induced cell damage by reducing reactive oxygen species (ROS) and malondialdehyde (MDA) levels, increasing catalase (CAT) activity, and improving cell proliferation and mitochondrial membrane potential. Moreover, hesperidin activated the Keap1/Nrf2/ARE signaling pathway by inducing the nuclear translocation of Nrf2 and the expression of its downstream genes NQO1 and HO-1, which are antioxidant enzymes involved in ROS scavenging and cellular redox balance. The protective effects of hesperidin were blocked by the Nrf2 inhibitor ML385, indicating that they were Nrf2 dependent. CONCLUSIONS: Our results suggest that hesperidin could protect bMECs from oxidative stress injury by activating the Nrf2 signaling pathway, suggesting that hesperidin as a natural antioxidant has positive potential as a feed additive or plant drug to promote the health benefits of bovine mammary.

Metabolic Changes in Serum and Milk of Holstein Cows in Their First to Fourth Parity Revealed by Biochemical Analysis and Untargeted Metabolomics.

The performance of dairy cows is closely tied to the metabolic state, and this performance varies depending on the number of times the cows have given birth. However, there is still a lack of research on the relationship between the metabolic state of Holstein cows and the performance of lactation across multiple parities. In this study, biochemical analyses and metabolomics studies were performed on the serum and milk from Holstein cows of parities 1-4 (H1, N = 10; H2, N = 7; H3, N = 9; H4, N = 9) in mid-lactation (DIM of 141 ± 4 days) to investigate the link between performance and metabolic changes. The results of the milk quality analysis showed that the lactose levels were highest in H1 (p = 0.036). The total protein content in the serum increased with increasing parity (p = 0.013). Additionally, the lipase activity was found to be lowest in H1 (p = 0.022). There was no difference in the composition of the hydrolyzed amino acids in the milk among H1 to H4. However, the free amino acids histidine and glutamate in the serum were lowest in H1 and highest in H3 (p < 0.001), while glycine was higher in H4 (p = 0.031). The metabolomics analysis revealed that 53 and 118 differential metabolites were identified in the milk and serum, respectively. The differential metabolites in the cows' milk were classified into seven categories based on KEGG. Most of the differential metabolites in the cows' milk were found to be more abundant in H1, and these metabolites were enriched in two impact pathways. The differential metabolites in the serum could be classified into nine categories and enriched in six metabolic pathways. A total of six shared metabolites were identified in the serum and milk, among which cholesterol and citric acid were closely related to amino acid metabolism in the serum. These findings indicate a significant influence of blood metabolites on the energy and amino acid metabolism during the milk production process in the Holstein cows across 1-4 lactations, and that an in-depth understanding of the metabolic changes that occur in Holstein cows during different lactations is essential for precision farming, and that it is worthwhile to further investigate these key metabolites that have an impact through controlled experiments.

Distinct microbial hydrogen and reductant disposal pathways explain interbreed variations in ruminant methane yield.

Ruminants are essential for global food security, but these are major sources of the greenhouse gas methane. Methane yield is controlled by the cycling of molecular hydrogen (H2), which is produced during carbohydrate fermentation and is consumed by methanogenic, acetogenic, and respiratory microorganisms. However, we lack a holistic understanding of the mediators and pathways of H2 metabolism and how this varies between ruminants with different methane-emitting phenotypes. Here, we used metagenomic, metatranscriptomic, metabolomics, and biochemical approaches to compare H2 cycling and reductant disposal pathways between low-methane-emitting Holstein and high-methane-emitting Jersey dairy cattle. The Holstein rumen microbiota had a greater capacity for reductant disposal via electron transfer for amino acid synthesis and propionate production, catalyzed by enzymes such as glutamate synthase and lactate dehydrogenase, and expressed uptake [NiFe]-hydrogenases to use H2 to support sulfate and nitrate respiration, leading to enhanced coupling of H2 cycling with less expelled methane. The Jersey rumen microbiome had a greater proportion of reductant disposal via H2 production catalyzed by fermentative hydrogenases encoded by Clostridia, with H2 mainly taken up through methanogenesis via methanogenic [NiFe]-hydrogenases and acetogenesis via [FeFe]-hydrogenases, resulting in enhanced methane and acetate production. Such enhancement of electron incorporation for metabolite synthesis with reduced methanogenesis was further supported by two in vitro measurements of microbiome activities, metabolites, and public global microbiome data of low- and high-methane-emitting beef cattle and sheep. Overall, this study highlights the importance of promoting alternative H2 consumption and reductant disposal pathways for synthesizing host-beneficial metabolites and reducing methane production in ruminants.

Ecological niches and assembly dynamics of diverse microbial consortia in the gastrointestine of goat kids.

Goats are globally invaluable ruminants that balance food security and environmental impacts, and their commensal microbiome residing in the gastrointestinal tract (GIT) is associated with animal health and productivity. However, the reference genomes and functional repertoires of GIT microbes in goat kids have not been fully elucidated. Herein, we performed a comprehensive landscape survey of the GIT microbiome of goat kids using metagenomic sequencing and binning, spanning a dense sampling regime covering three gastrointestinal compartments spatially and five developmental ages temporally. We recovered 1002 high-quality metagenome-assembled genomes (termed the goat kid GIT microbial catalog [GKGMC]), 618 of which were novel. They encode more than 2.3 million nonredundant proteins, and represent a variety of carbohydrate-degrading enzymes and metabolic gene clusters. The GKGMC-enriched microbial taxa, particularly Sodaliphilus, expanded the microbial tree of life in goat kids. Using this GKGMC, we first deciphered the prevalence of fiber-degrading bacteria for carbohydrate decomposition in the rumen and colon, while the ileal microbiota specialized in the uptake and conversion of simple sugars. Moreover, GIT microorganisms were rapidly assembled after birth, and their carbohydrate metabolic adaptation occurred in three phases of progression. Finally, phytobiotics modified the metabolic cascades of the ileal microbiome, underpinned by the enrichment of Sharpea azabuensis and Olsenella spp. implicated in lactate formation and utilization. This GKGMC reference provides novel insights into the early-life microbial developmental dynamics in distinct compartments, and offers expanded resources for GIT microbiota-related research in goat kids.

Prospects and Challenges of Bacteriophage Substitution for Antibiotics in Livestock and Poultry Production.

The overuse and misuse of antibiotics in the livestock and poultry industry has led to the development of multi-drug resistance in animal pathogens, and antibiotic resistance genes (ARGs) in bacteria transfer from animals to humans through the consumption of animal products, posing a serious threat to human health. Therefore, the use of antibiotics in livestock production has been strictly controlled. As a result, bacteriophages have attracted increasing research interest as antibiotic alternatives, since they are natural invaders of bacteria. Numerous studies have shown that dietary bacteriophage supplementation could regulate intestinal microbial composition, enhance mucosal immunity and the physical barrier function of the intestinal tract, and play an important role in maintaining intestinal microecological stability and normal body development of animals. The effect of bacteriophages used in animals is influenced by factors such as species, dose, and duration. However, as a category of mobile genetic elements, the high frequency of gene exchange of bacteriophages also poses risks of transmitting ARGs among bacteria. Hence, we summarized the mechanism and efficacy of bacteriophage therapy, and highlighted the feasibility and challenges of bacteriophage utilization in farm animal production, aiming to provide a reference for the safe and effective application of bacteriophages as an antibiotic alternative in livestock and poultry.

Novel techniques for the mass production of nutritionally improved, fungus-treated lignocellulosic biomass for ruminant nutrition.

BACKGROUND: Laboratory-scale experiments have shown that treatment with selective lignin-degrading white-rot fungi improves the nutritional value and ruminal degradability of lignocellulosic biomass (LCB). However, the lack of effective field-applicable pasteurization methods has long been recognized as a major obstacle for scaling up the technique for fungal treatment of large quantities of LCB for animal feeding. In this study, wheat straw (an LCB substrate) was subjected to four field-applicable pasteurization methods - hot-water, formaldehyde fumigation, steam, and hydrated lime - and cultured with Pleurotus ostreatus grain spawn for 10, 20, and 30 days under solid-state fermentation. Samples of untreated, pasteurized but non-inoculated and fungus-treated straws were analyzed for chemical composition, aflatoxin B1 (AFB1 ), and in vitro dry matter digestibility (IVDMD), in vitro total gas (IVGP), methane (CH4 ), and volatile fatty acid (VFA) production. RESULTS: During the 30-day fungal treatment, steam and lime pasteurized straws had the greatest loss of lignin, resulting in marked improvements in crude protein (CP), IVDMD, IVGP, and total VFAs. Irrespective of the pasteurization method, the increase in IVDMD during fungal treatment was linearly (R2 = 0.77-0.92) related to lignin-loss in the substrate during fungal treatment. The CH4 production of the fungus-treated straw was not affected by the pasteurization methods. Aflatoxin B1 was within the safe level (<5 µg kg-1 ) in all pasteurized, fungus treated straws. CONCLUSION: Steam and lime were promising field-applicable pasteurization techniques to produce nutritionally improved fungus-treated wheat straw to feed ruminants. Lime pasteurization was more economical and did not require expensive energy inputs. © 2023 Society of Chemical Industry.

Mixed ensiling plus nitrate destroy fiber structure of rape straw, increase degradation, and reduce methanogenesis through in vitro ruminal fermentation.

BACKGROUND: Better utilization of rape straw can provide alternative strategies for sustainable ruminant and food production. The research reported here investigated changes in the carbohydrate composition of rape straw as a result of mixed ensiling with whole-crop corn or inoculated with nitrate, and the consequent effects on ruminal fermentation through in vitro batch culture. The three treatments included: rape straw and corn silage (RSTC), and ensiling treatment of rape straw with whole-crop corn (RSIC) or with calcium nitrate inoculation (RSICN). RESULTS: Ensiling treatment of rape straw and whole-crop corn or plus nitrate enriched lactic acid bacteria and lactate. The treatments broke the fiber surface connections of rape straw, leading to higher neutral detergent soluble (NDS) content and lower fiber content. Ensiling treatments led to greater (P < 0.05) dry matter degradation (DMD), molar proportions of propionate and butyrate, relative abundance of the phylum Bacteroidetes and genus Prevotella, and lower (P < 0.05) methane production in terms of g kg-1 DMD, molar proportions of acetate, and lower acetate to propionate ratio than the RSTC treatment. The RSICN treatment led to the lowest (P < 0.05) hydrogen concentration and methane production among the three treatments. CONCLUSION: Ensiling treatments of rape straw and whole-crop corn destroy the micro-structure of rape straw, promote substrate degradation by enriching the phylum Bacteroidetes and the genus Prevotella, and decrease methane production by favoring propionate and butyrate production. Nitrate inoculation in the ensiling treatment of rape straw and whole-crop corn further decreases methane production without influencing substrate degradation by providing an additional hydrogen sink. © 2023 Society of Chemical Industry.

Optimizing corn silage quality during hot summer conditions of the tropics: investigating the effect of additives on in-silo fermentation characteristics, nutrient profiles, digestibility and post-ensiling stability.

Corn crop grown and ensiled at high temperature have lower water soluble carbohydrates (WSC), epiphytic lactic acid bacteria (LAB) population, lactic acid concentration, fermentation quality and aerobic stability. This study systematically investigated the effects of heterofermentative LAB (hetLAB), homofermentative LAB (homLAB), molasses and their mixture (MIX) on in-silo fermentation characteristics, chemical profiles, Cornell Net Carbohydrate and Protein System (CNCPS) carbohydrate subfractions, in vitro digestibility (DMD), microbial count, and post-ensiling aerobic stability of whole crop corn silage during hot summer (30 to 45°C) condition. Corn hybrids (P30K08 and DK6789) were ensiled at targeted dry matter (DM) of 330 g/kg for 0, 3, 7, 21, and 150 days in 3 L silos, without additive (CCS) or treated with hetLAB (4×106 cfu/g Lactobacillus buchneri), homLAB (1×106 cfu/g of L. plantarum), molasses (3% of fresh forage) or MIX (half of individual doses of homLAB, hetLAB and molasses) additives. The CCS, homLAB, hetLAB, molasses, or MIX treated chopped material of each hybrid were ensiled in 16 replicate silos at a density of 260 kg of DM/m3. Compared to CCS, the additives significantly improved silage nutritional and fermentation quality, DM digestibility (in vitro), count of LAB, DM recovery and aerobic stability, and decreased counts of yeast and mold. Among the inoculants, the homLAB and MIX inoculated silages had greatest improvement in fermentation quality and nutritional value. The homLAB produced corn silage with the highest (P < 0.05) content of lactic acid, and soluble carbohydrates, and lowest contents of acetic acid, NH3-N and pH, demonstrating desirable and restricted in silo fermentation. On the other hand, the hetLAB inoculated silages had the greatest (P < 0.05) value of acetic acids, highlighting greater aerobic stability. Interestingly, the MIX silages followed the hetLAB in acetic acid value and homLAB in lactic acid value. Notably, without additive stable pH was not achieved during 21 days, with application of molasses, hetLAB and the MIX inoculants stable pH was achieved during 7 days, and with homLAB stable pH was achieved during the first 3 days of ensiling. The greatest numbers of viable LAB were recorded in homLAB (8.13 log cfu/g) and MIX (7.89 log cfu/g) inoculated silages, while the lowest for CCS (6.29 log cfu/g). The lowest yeast (1.48 log cfu/g) and mold (0.22 log cfu/g) were recorded for hetLAB inoculated silage. The greatest (P < 0.05) DM recovery was recorded for hetLAB (97.3%) and MIX (96.9%), and the lowest for the control silage (92.9%). All additives significantly improved the aerobic stability of corn silage, and the greatest value of >72 h was recorded for hetLAB and MIX inoculats, and the lowest for CSC (25 h). In conclusion, additives application can improve fermentation quality, nutritional value, DM recovery and aerobic stability of whole crop corn silage under hot summer conditions of the tropics. The MIX inoculant showed potential to improve in-silo fermentation, and aerobic stability at the same time, however, further investigation are required, particularly with respect of dose rate.

Blood Metabolites and Faecal Microbial Communities in Nonpregnant and Early Gestation Ewes in Highly Cold Areas.

Ewes undergo complex metabolic changes during pregnancy. Understanding the specific process of these changes is a necessary prerequisite in ewes for regulating and intervening in order to maintain pregnancies. However, there have been relatively few studies on the specific changes that occur in nutritional metabolism in pregnant ewes during early gestation, especially for some landrace ewes in highly cold areas. Therefore, this study aimed to (1) elucidate the changes in metabolites and microbial communities in pregnant ewes during early gestation using metabolomics and 16S ribosomal RNA gene (rDNA) amplicon sequencing approaches, and to (2) discover novel early pregnancy-induced biomarkers in the blood and faeces. Rams were placed together with ewes on D0 and removed on D45. During early gestation, blood and faecal samples were collected from ewes in a highly cold area for analysing the metabolites and microbial communities; these were retrospectively classified as the early gestation pregnant (EP) ewe group or the nonpregnant (NP) ewe group based on the lambing status recorded during the expected delivery period. The differences in the plasma biochemical parameters, plasma metabolites, and faecal microbial communities of pregnant and nonpregnant ewes were characterised. The GC, IL-6, O-acetyl-l-serine, L-glutamine, and 6-acetamido-2-oxohexanoic acid were screened out as potential biomarkers for evaluating the occurrence of early pregnancy. These novel early pregnancy-induced metabolites discovered in ewes might allow for the development of technologies to detect early pregnancies in sheep in highly cold areas.

Microbiome-transcriptome analysis reveals that dietary supplementation with macleaya cordata extract alters multiple immune pathways with minimal impact on microbial structure.

Background: As a potential antibiotic alternative, macleaya cordata extract (MCE) has anti-inflammatory, antioxidant, and antimicrobial properties. This study was conducted to assess the impact of MCE supplementation on the gut microbiota and its interplay with the host in young goats. Thirty female black goats with similar body weight (5.63 ± 0.30 kg) were selected and randomly allotted into one of three diets: a control diet (Control), a control diet with antibiotics (Antibiotics, 21 mg/kg/day vancomycin and 42 mg/kg/day neomycin), and a control diet with MCE (MCE, 3.75% w/w premix). Results: Principal coordinate analysis of the microbial community showed that samples of Antibiotic clustered separately from both Control and MCE (p < 0.001). The random forest analysis revealed that, in comparison to the Control group, the impact of Antibiotics on the microbiota structure was more pronounced than that of MCE (number of featured microbiota, 13 in Antibiotics and >6 in MCE). In addition, the pathways of significant enrichment either from DEGs between Antibiotics and Control or from DEGs between MCE and Control were almost identical, including Th17 cell differentiation, butanoate metabolism, T-cell receptor signaling pathway, intestinal immune network for IgA production, antigen processing and presentation, and ABC transporters. Furthermore, an integrative analysis indicated that significant positive correlations (p < 0.05) were observed between HEPHL1 and the featured biomarkers Atopostipes, Syntrophococcus, Romboutsia, and Acinetobacter in the MCE group. Conversely, several significant negative correlations (p < 0.05) were identified between HEPHL1 and the featured biomarkers Clostridium_XlVa, Phascolarctobacterium, Desulfovibrio, Cloacibacillus, Barnesiella, Succinatimonas, Alistipes, Oscillibacter, Ruminococcus2, and Megasphaera in the Antibiotics group. Conclusion: Collectively, the analysis of microbiome-transcriptome data revealed that dietary supplementation with MCE produced significant alterations in multiple immune pathways, while having minimal impact on the microbial structure.

The epithelial transcriptome and mucosal microbiota are altered for goats fed with a low-protein diet.

Introduction: Feeding low protein (LP) diet to animals impose severe challenge to animals' immune homeostasis. However, limited knowledge about the underlying adaption mechanism of host and ruminal microbiota responding to LP diet were well understood. Herein, this study was performed to examine the changes in relative abundance of ruminal microbiota and host ruminal mucosal transcriptome profiles in response to a LP diet. Methods: A total of twenty-four female Xiangdong balck goats with similar weight (20.64 ± 2.40 kg) and age (8 ± 0.3 months) were randomly assigned into two groups, LP (5.52% crude protein containing diet) and CON (10.77% crude protein containing diet) groups. Upon completion of the trial, all goats were slaughtered after a 16-hour fasting period in LiuYang city (N 28°15', E 113°63') in China. HE staining, free amino acids measurement, transcriptome analysis and microbiome analysis were applied to detect the morphology alterations, free amino acids profile alterations and the shift in host ruminal mucosal transcriptome and ruminal microbiota communities. Results: Firstly, the results showed that feeding LP diet to goats decreased the rumen papilla width (P = 0.043), surface area (P = 0.013) and total ruminal free amino acids concentration (P = 0.016). Secondly, microbiome analysis indicated that 9 microbial genera, including Eubacterium and Prevotella, were enriched in LP group while 11 microbial genera, including Butyrivibrio and Ruminococcus, were enriched in CON group. Finally, in terms of immune-related genes, the expression levels of genes involved in tight junction categories (e.g., MYH11, PPP2R2C, and MYL9) and acquired immunity (e.g., PCP4 and CXCL13) were observed to be upregulated in the LP group when compared to the CON group. Conclusion: Under the LP diet, the rumen exhibited increased relative abundance of pathogenic microbiota and VFA-degrading microbiota, leading to disruptions in immune homeostasis within the host's ruminal mucosa. These findings indicate that the ruminal microbiota interacts with host results in the disruption in animals' immune homeostasis under LP diet challenge.

Application of different proportions of sweet sorghum silage as a substitute for corn silage in dairy cows.

This experiment explored the effects of different proportions of sweet sorghum silage as a substitute for corn silage on dry matter intake (DMI), milk yield, milk quality, apparent digestibility, rumen fermentation parameters, serum amino acid profile, and rumen microbial composition of dairy cows. A total of 32 mid-lactation Holstein dairy cows with similar body weights and parities were randomly divided into four treatments: 100% corn silage +0% sorghum silage (CON), 75% corn silage +25% sorghum silage (CS1), 50% corn silage +50% sorghum silage (CS2), and 25% corn silage +75% sorghum silage (CS3). The milk yield was increased (linear, p = .048) as the proportion of sweet sorghum increased. Linear (p = .003) and quadratic (p = .046) increased effects were observed in milk fat as corn silage was replaced with sorghum silage. Compared with the CON diet group, the CS2 and CS3 diet groups had lower dry matter (DM) (linear, p < .001), ether extract (EE) (linear, p < .001), and gross energy (GE) (linear, p = .001) digestibility of the dairy cows. The ruminal fluid aspartate (Asp) level decreased (linear, p = .003) as the proportion of sweet sorghum increased. Linear (p < .05) and quadratic (p < .05) increased effects were observed for the contents of threonine (Thr), glycine (Gly), valine (Val), leucine (Leu), tyrosine (Tyr), and histidine (His) in rumen fluid with the replacement of corn silage with sorghum silage. Cows fed the CS3 diet had greater Faecalibacterium, Bacteroides, and Prevotella ruminicola content/copy number than those fed the CON diet (p < .05). In conclusion, feeding sorghum silage as a replacement for corn silage could increase the milk yield and fat, promote the growth of rumen microbes, and provide more rumen fluid amino acids for the body and microbial utilization. We believe that sorghum silage is feasible for dairy cows, and it is reasonable to replace corn silage with 75% sorghum silage.

Genome wide transcriptome analysis provides bases on hepatic lipid metabolism disorder affected by increased dietary grain ratio in fattening lambs.

BACKGROUND: The liver is a principal metabolic organ and has a major role in regulating lipid metabolism. With the development of rapidly fattening livestock in the modern breeding industry, the incidence of hepatic steatosis and accumulation in animals was significantly increased. However, the molecular mechanisms responsible for hepatic lipid metabolic disturbances in a high concentrate diet remain unclear. The objective of this study was to evaluate the effects of increasing concentrate level in a fattening lamb diet on biochemical indices, hepatic triglycerides (TG) concentration, and hepatic transcriptomic profiles. In the present study, 42 weaned lambs (about 3 ± 0.3 months old) were randomly assigned to the GN60 group (60% concentrate of dry matter, GN60, n = 21) or GN70 group (70% concentrate of dry matter, n = 21) for a 3-months feeding trial. RESULTS: No difference was observed in the growth performance or plasma biochemical parameters between the GN60 group and the GN70 group. The hepatic TG concentration was higher in the GN70 group than GN60 group (P < 0.05). Hepatic transcriptomic analysis showed that there were 290 differentially expressed genes identified between GN60 and GN70 groups, with 125 genes up-regulated and 165 genes down-regulated in the GN70 group. The enriched Gene Ontology (GO) items and KEGG pathways and protein-protein interaction (PPI) network of differentially expressed genes (DEGs) revealed that the majority of enriched pathways were related to lipid metabolism. Further analysis revealed that the fatty acid synthesis was up-regulated, while fatty acid transport, oxidation, and TG degradation were down-regulated in the GN70 group when compared with the GN60 group. CONCLUSIONS: These results indicated that GN70 induced excess lipid deposition in the liver of lambs during the fattening period, with high synthesis rates and low degradation rates of TG. The identified mechanisms may help understand hepatic metabolism in lambs with a high concentrate diet and provide insight into decreasing the risk of liver metabolism disorder in animals.

Effects of organic and inorganic selenium on selenium bioavailability, growth performance, antioxidant status and meat quality of a local beef cattle in China.

Selenium (Se) is an essential nutrient with multiple health benefits to humans and animals. Cattle generally require dietary Se supplementation to meet their daily requirements. The two main forms of dietary Se in cattle are organic Se and inorganic Se. Data comparing the health and productivity effects of organic Se and inorganic Se on cattle are still insufficient, and it is necessary to conduct more research to evaluate the bioavailability, nutritional value, deposition, and body functions of Se sources in different breeds and physiological stages of cattle raised in areas with different Se levels. The objectives of this study were to determine the effects of organic and inorganic sources of Se on plasma biochemical indices, Se bioavailability, deposition in body tissues and organs, growth performance, antioxidant capacity and meat quality of beef cattle raised in Se-deficient areas. Fifteen Chinese Xiangzhong Black beef cattle with an average weight of 254.5 ± 8.85 kg were assigned to three dietary groups. The three groups were fed the same basal ration and supplemented with either an inorganic [sodium selenite (SS)] or organic [selenomethionine (SM) or Se-enriched yeast (SY)] source of Se (0.1 mg/kg dry matter) for 60 days. At the end of the experiment, three cattle from each group were randomly selected and slaughtered, and samples were collected from tissues and organs for analysis. The results revealed that growth performance, slaughter performance, Se content of tissues and organs, meat quality characteristics including chemical composition, pH45min, pH24h, drip loss, and cooking losses did not differ (p > 0.05) due to supplementation of the different organic and inorganic sources of Se. SM and SY were more effective in increasing (p < 0.05) immunoglobulin M (IgM) concentrations in the blood and reducing (p < 0.05) malondialdehyde (MDA) content in the longissimus dorsi than SS. In conclusion, organic Se is more effective than inorganic Se in improving the immune and antioxidant capacity of Chinese Xiangzhong Black beef cattle.

Effects of dietary N-carbamylglutamate on rumen fermentation parameters, and bacterial community diversity of Holstein dairy cows in Tibet.

Introduction: The Tibetan Plateau is characterized by low temperature and hypoxia. N-carbamylglutamic acid (NCG) can increase blood oxygen saturation, and have the potential to be used to prevent the high-altitude hypoxia stress state of cows. However, its beneficial effect on the rumen microbiota of Holstein dairy cows remains unclear. Methods: Hence, the experiments 12 multiparous (parity ranged from 2 to 7) Holstein dairy cows (413.0 ± 42 kg) were randomly assigned to 2 treatments with 6 replicates in each treatment: basal diet (CON, control group) and basal diet plus 20 g/d/cow of NCG (NCG, experiment group), respectively. To study the effects of dietary NCG supplementation on rumen microbiota of Holstein dairy cows in Tibet. The experiment lasted for 45 days, with 15 days of pre-feeding and 30 days of formal trail period. Results: The results showed that ruminal NH3-N concentration in NCG group was lower (p < 0.05) than that in the CON group, while molar proportion of acetic acid and total volatile fatty acid (VFA) concentration were increased (p < 0.05) with the addition of NCG. Microbial diversity increased (p < 0.05) in NCG group, with Bacteroidetes, Firmicutes, and Patescibacteria as the most abundant phyla. The KEGG pathway analysis showed that the potential function of ruminal bacteria was mainly enriched in metabolism (carbohydrates, amino acids, lipids, energy, and nucleotides) and genetic information processing (replication, repair, and translation). Conclusion: In conclusion, NCG can improve rumen nitrogen utilization, total VFA and acetic acid production, and increase rumen microbial diversity, all of which could make the introduced Holstein dairy cows to better adapt to the harsh environment in Tibet and improve their production performance.

Fermentation of increasing ratios of grain starch and straw fiber: effects on hydrogen allocation and methanogenesis through in vitro ruminal batch culture.

Grain starch has a faster rate of rumen fermentation than straw fiber and causes a rapid increase in ruminal molecular hydrogen (H2) partial pressure, which may promote other H2 sinks to compete H2 away from methanogenesis. The study was designed to investigate the effects of increasing ratios of grain starch to straw fiber on hydrogen allocation and methanogenesis through in vitro ruminal batch incubation. Corn grain and corn straw were employed as starch and fiber source respectively. Seven treatments were the ratios of corn grain to corn straw (RGS) being 0:6, 1:5, 2:4, 3:3, 4:2, 5:1, and 6:0. Elevating RGS increased dry matter (DM) degradation and decreased methane (CH4) and hydrogen gas (gH2) production relative to DM degraded. Elevating RGS increased volatile fatty acid (VFA) concentration, propionate molar percentage and microbial protein (MCP) concentration, decreased acetate molar percentage, acetate to propionate ratio and estimated net metabolic hydrogen ([H]) production relative to DM degraded. Elevating RGS decreased the molar percentage of [H] utilized for CH4 and gH2 production. In summary, increasing ratios of grain starch to straw fiber altered rumen fermentation pathway from acetate to propionate production, reduced the efficiency of [H] production with the enhancement of MCP synthesis, and led to a reduction in the efficiency of CH4 and gH2 production.

Evaluation of stirring time through a rumen simulation technique: Influences on rumen fermentation and bacterial community.

Introduction: Rumen motility is a key element that influences ruminant nutrition, whereas little is known about the effects of rumen contraction duration on rumen fermentation and ruminal microbiome. We previously reported that proper rotation speed of a rumen simulation technique (RUSITEC) system enhanced rumen fermentation and microbial protein (MCP) production. In the present study, different contraction durations and intervals were simulated by setting different stirring times and intervals of the stirrers in a RUSITEC system. The objective of this trial was to evaluate the influences of stirring time on rumen fermentation characteristics, nutrient degradation, and ruminal bacterial microbiota in vitro. Methods: This experiment was performed in a 3 × 3 Latin square design, with each experimental period comprising 4 d for adjustment and 3 d for sample collection. Three stirring time treatments were set: the constant stir (CS), the intermittent stir 1 (each stir for 5 min with an interval of 2 min, IS1), and the intermittent stir 2 (each stir for 4 min with an interval of 3 min, IS2). Results: The total volatile fatty acid (TVFA) concentration, valerate molar proportion, ammonia nitrogen level, MCP density, protozoa count, disappearance rates of dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber, emissions of total gas and methane, and the richness index Chao 1 for the bacterial community were higher (p < 0.05) in the IS1 when compared to those in the CS. The greatest TVFA, MCP, protozoa count, nutrient disappearance rates, gas productions, and bacterial richness indices of Ace and Chao 1 amongst all treatments were observed in the IS2. The relative abundance of the genus Treponema was enriched (p < 0.05) in CS, while the enrichment (p < 0.05) of Agathobacter ruminis and another two less known bacterial genera were identified in IS2. Discussion: It could be concluded that the proper reduction in the stirring time might help to enhance the feed fermentation, MCP synthesis, gas production, and the relative abundances of specific bacterial taxa.

An integrated transcriptome and microbial community analysis reveals potential mechanisms for increased immune responses when replacing silybum marianum meal with soybean meal in growing lambs.

Silybum marianum meal is a by-product that remains silymarin complex and is perceived as a potential-protein source. The potential and its mechanism of silybum marianum meal as a protein supplement in ruminants were evaluated by testing the growth performance, biochemical parameters, cytokine levels, gut transcriptome and microbial community profiles. Forty-two male Hulunbeier growing lambs (aged about 3-month-old; averaged body weight of 21.55 kg) were randomly divided into the CON (with 10% soybean meal) and SIL groups (with 10% silybum marianum meal). There was no significant difference in growth performance, feed intakes, or serum biochemical parameters between CON and SIL. The serum levels of IL-1ß, TNF-α, TGF-ß, HGF, and VEGF were all increased (p < 0.05) in the SIL group as compared with the CON group. Transcriptome gene set enrichment analysis (GSEA) revealed that the core genes in the rumen from SIL group were enriched with fructose and mannose metabolism, while the core genes in the ileum were enriched for three biological process, including digestive tract development, positive regulation of MAPK cascade, and regulation of I-kappaB kinase/NF-kappaB signaling. The 16S rDNA results showed that the relative abundance of Bacteroidetes, Firmicutes, Synergistetes, and Verrucomicrobia in the rumen from SIL group was significantly higher than that in CON group (p < 0.05), whereas Proteobacteria was significantly lower than that in CON group (p < 0.05). The LEfSe analysis showed that the genera Pyramidobacter, Saccharofermentans, Anaerovibrio, Oscillibacter and Barnesiella were enriched in the rumen from SIL group, whereas Sharpea was enriched in the CON group (LDA > 2). In the ileum, there were no significant differences in the phylum-level classification of microbes observed. At the genus level, the relative abundances of Bifidobacterium and Ruminococcus in the ileum from SIL group were significantly higher than that in the CON group (p < 0.05), whereas the relative abundance of Clostridium_XI was lower (p < 0.05). Correlation analysis showed that Clostridium_XI was negatively correlated with VEGF, TGF-ß, TNF-α and HGF (p < 0.05). Core genes BMP4 and CD4 were negatively correlated with Clostridium_XI (p < 0.05). Our results indicated that supplementing silybum marianum meal as a replacement for soybean meal resulted in increased cytokines production without affecting growth performance in growing lambs, and the enrichment of immune-related genes and altered microbial community in the ileum were contributed to the increased immune responses.

Temporal changes in muscle characteristics during growth in the goat.

This study aimed to explore the temporal accumulative process of functional components and take insight into their dynamic regulatory metabolic pathways in the longissimus during growth in goats. Results showed that the intermuscular fat content, cross-sectional area and fast- to slow-switch fiber ratio of the longissimus were synchronously increased from d1 to d90. The dynamic profiles of functional components and transcriptomic pathways of the longissimus both exhibited two distinct phases during animal development. Expression of genes involved in de novo lipogenesis was increased from birth to weaning, leading to the accumulation of palmitic acid in the first phase. Accumulation of functional oleic acid, linoleic acid and linolenic acid in the second phase was dominatingly driven by enhancement in expression of genes related to fatty acid elongation and desaturation after weaning. A shift from serine to glycine production was observed after weaning, which was linked to the expression profile of genes involved in their interconversion. Our findings systematically reported the key window and pivotal targets of the functional components' accumulation process in the chevon.