Hybridization promotes growth performance by altering rumen microbiota and metabolites in sheep.

Hybridization can substantially improve growth performance. This study used metagenomics and metabolome sequencing to examine whether the rumen microbiota and its metabolites contributed to this phenomenon. We selected 48 approximately 3 month-old male ♂Hu × â™€Hu (HH, n = 16), ♂Poll Dorset × â™€Hu (DH, n = 16), and ♂Southdown × â™€Hu (SH, n = 16) lambs having similar body weight. The sheep were fed individually under the same nutritional and management conditions for 95 days. After completion of the trial, seven sheep close to the average weight per group were slaughtered to collect rumen tissue and content samples to measure rumen epithelial parameters, fermentation patterns, microbiota, and metabolite profiles. The final body weight (FBW), average daily gain (ADG), and dry matter intake (DMI) values in the DH and SH groups were significantly higher and the feed-to-gain ratio (F/G) significantly lower than the value in the HH group; additionally, the papilla height in the DH group was higher than that in the HH group. Acetate, propionate, and total volatile fatty acid (VFA) concentrations in the DH group were higher than those in the HH group, whereas NH3-N concentration decreased in the DH and SH groups. Metagenomic analysis revealed that several Prevotella and Fibrobacter species were significantly more abundant in the DH group, contributing to an increased ability to degrade dietary cellulose and enrich their functions in enzymes involved in carbohydrate breakdown. Bacteroidaceae bacterium was higher in the SH group, indicating a greater ability to digest dietary fiber. Metabolomic analysis revealed that the concentrations of rumen metabolites (mainly lysophosphatidylethanolamines [LPEs]) were higher in the DH group, and microbiome-related metabolite analysis indicated that Treponema bryantii and Fibrobacter succinogenes were positively correlated with the LPEs. Moreover, we found methionine sulfoxide and N-methyl-4-aminobutyric acid were characteristic metabolites in the DH and SH groups, respectively, and are related to oxidative stress, indicating that the environmental adaptability of crossbred sheep needs to be further improved. These findings substantially deepen the general understanding of how hybridization promotes growth performance from the perspective of rumen microbiota, this is vital for the cultivation of new species and the formulation of precision nutrition strategies for sheep.

Allostasis as a consequence of high heat load in grain-fed feedlot cattle.

Heat wave intensity, frequency, and duration are increasing in many regions of the world, including locations where highly productive livestock are raised. There are animal health and welfare, as well as economic impacts from these events. In this study, the physiological responses of grain-fed steers during a high heat load challenge through to recovery in climate-controlled rooms (CCR) were intensively evaluated. Two cohorts of 12 Black Angus steers (BW, 615.4 ±â€…40.1 kg) sequentially underwent a simulated heatwave event that consisted of 3 phases in the CCR: PreChallenge (5 d duration and temperature humidity index (THI) range of 65 to 71), Challenge (7-d duration and THI 66 to 95 with diurnal cycling), and Recovery (5 d duration and THI 65 to 70). The Challenge period was modeled on a severe heat wave, characterized by 3 very hot days. Individual rumen temperature (RumT, °C) was collected every 10 min, and respiration rate (RR, breaths per minute), panting score (PS), and water usage (L·steer-1·day-1) were obtained at multiple time points daily, by trained observers. Individual animal daily DMI was also determined. Morning (0700 hours) rectal temperature (RecT, °C) was measured on days 3, 5, 7 to 13, 15, and 17. Not unexpectedly, RumT, RecT, RR, and PS rose during Challenge and fell rapidly as conditions eased. Conversely, DMI was reduced during Challenge. During the transition between PreChallenge and Challenge, there were abrupt increases in RumT, and RR. It was also very apparent that during Recovery the steers did not return to the baseline PreChallenge state. Compared to PreChallenge, Recovery was characterized by persistent lowered daily mean RumT (P = 0.0010), RecT (P = 0.0922), RR (P = 0.0257), PS (P ≤ 0.0001), and DMI (P ≤ 0.0001). These results provide evidence that these steers have undergone an allostatic response in response to high heat load, and the new adjusted physiological state post-heat event may not be transient.

Effects of Chitosan-Based Additive on Rumen Fermentation and Microbial Community, Nutrients Digestibility and Lactation Performance in Goats.

Recently, the potential of using chitosan (CHI) as a feed additive to enhance ruminal fermentation and improve animal performance has gained increasing attention in ruminant nutrition. This study was undertaken to investigate the effect of dietary supplementation with increasing doses of CHI on rumen fermentation attributes and microbial composition, digestibility and milk performance in Dhofari goats. Twenty-four lactating goats (27 ± 1.8 kg of initial live body weight) were fed a control diet comprising of Rhodes grass hay plus a concentrate feed mixture. Goats were assigned to one of three experimental treatments (n = 8 per treatment) as: (1) control diet with no supplement (CTRL), (2) control diet with 0.300 g/day CHI (CHI0.3) and (3) control diet supplemented with 0.600 g/day CHI (CHI0.6) for a 45-day experimental period. Dietary supplementation with increasing doses of CHI decreased (p < 0.05) linearly ruminal pH (p = 0.023), total short chain fatty acids concentrations (p = 0.011), acetate (p = 0.013) and butyrate (p = 0.042) proportions, acetate to propionate ratio (p < 0.001), estimated methane (CH4) production (p < 0.001), ammonia nitrogen concentrations (p = 0.003) and protozoa abundance (p = 0.003). However, the ruminal propionate proportion augmented (p = 0.002) linearly with increasing doses of CHI in the diet. Increasing doses of CHI linearly increased the abundance of the ruminal propionate-producing bacteria, while diminished acetate and CH4-producing bacteria (p < 0.05). Serum total protein (p = 0.037) and glucose (p = 0.042) levels linearly increased as CHI doses increased in the diet. However, serum UREA levels decreased linearly (p = 0.002) by 21% with increasing CHI amounts in the diet. The digestibility of organic matter, crude protein and neutral detergent fibre increased linearly with the increasing CHI doses (p < 0.05). Neither linear nor quadratic responses (p > 0.05) were observed in daily milk yield and feed efficiency by supplementing the diet with CHI. In conclusion, supplementing the diet with CHI at a dose of 0.600 g/day as a feed additive for dairy goats reduced estimated CH4 generation and improved fibre and protein digestion, with no influence on feed intake, milk yield or composition.

Effects of yeast cultures on meat quality, flavor composition and rumen microbiota in lambs.

Since the banning of antibiotics, the use of feed additives to improve meat quality to satisfy people's pursuit of high quality has become a research hotspot. Yeast culture (YC) is rich in proteins, mannan oligosaccharides, peptides, and yeast cell metabolites, etc., and its use as a feed additive has a positive impact on improving meat quality. So the study aimed to provide a theoretical basis for YC improving mutton flavor and quality by detecting and analyzing the effects of YC on muscle physicochemical properties, amino acids, fatty acids, flavor composition, expression of related genes, and rumen microbiota of lambs. A total of 20 crossbred F1 weaned lambs (Australian white sheep♂ × Hu sheep♀; average 23.38 ± 1.17 kg) were randomly assigned to 2 groups, the control group (CON) and the 1.0% YC supplemented group (YC) (n = 10), and were reared in separate pens. The experiment had a pre-feeding period of 10 d and a treatment period of 60 d. After the experiment, 6 lambs in each group were randomly selected for slaughtering. The results showed that dietary YC supplementation increased rumen total VFA and acetate concentrations (p < 0.05), and muscle carcass fat (GR), a∗ value, intramuscular fat (IMF), lysine (Lys), arginine (Arg), nonessential amino acid (NEAA), oleic acid (C18:1n9c), and eicosanoic acid (C20:1) contents were significantly increased (p < 0.05), while cooking loss and γ-linolenic acid (C18: 3n6) were decreased (p < 0.05). Furthermore, we found that dietary YC improved the types of flavor compounds, and the key flavor substances such as hexanal, nonanal, styrene, benzaldehyde, p-xylene, and 1-octen-3-ol contents were changed (p < 0.05). Additionally, the expression of fat metabolism related genes PPARγ, FASN, and FABP4 were increased. Adding 1% YC to lamb diets increased profits by 47.70 CNY per sheep after 60 d of fattening. All of which indicated that YC could improve meat quality, especially flavor, which may be related to the regulation of the relative abundance of rumen microorganisms Bacteroidota, Prevotella_7, Succiniclasticum and Lachnospiraceae_NK3A20_group.

Prepartum supplementation of dairy cows with inorganic selenium, organic selenium or rumen-protected choline does not affect carotenoid composition or colour characteristics of bovine colostrum or transition milk.

Minerals are supplemented routinely to dairy cows during the dry period to prevent metabolic issues postpartum. However, limited information exists on the impacts of mineral supplementation on colostrum carotenoids. This study aimed to determine the effects of prepartum supplementation with three micro-nutrients; inorganic selenium (INORG), organic selenium (ORG) or rumen-protected choline (RPC) on the carotenoid content of bovine colostrum and transition milk (TM) from pasture-based dairy cows. A total of 57 (12 primiparous and 45 multiparous) Holstein-Friesian (HF) and HF × Jersey (JEX) cows were supplemented daily for 49 ± 12.9 d before calving. Colostrum samples were collected from all cows immediately postpartum and TM one to five (TM1-TM5) were collected from a sub-set of 15 cows (five per treatment group) at each consecutive milking postpartum. Carotenoid concentration was determined using ultra-high performance liquid chromatography - diode array detection (UHPLC-DAD). With the use of transmittance, the colour index and colour parameters a*, b* and L* were used to determine colour variations over this period. Prepartum supplementation did not have a significant effect on colostrum ß-carotene concentration or colour. Positive correlations between ß-carotene and colour parameter b* (R2 = 0.671; P < 0.001) and ß-carotene and colour index (R2 = 0.560; P < 0.001) were observed. Concentrations of ß-carotene were highest in colostrum (1.34 µg/g) and decreased significantly with each milking postpartum (TM5 0.31 µg/g). Breed had a significant effect on colostrum colour with JEX animals producing a greater b* colostrum than HF animals (P = 0.030). Primiparous animals produced colostrum with the weakest colour compared to second or ≥third parity animals (P = 0.042). Despite statistical increases in the b* parameter in colostrum from JEX cows and multiparous cows, ß-carotene concentrations did not significantly increase suggesting that other factors may influence colostrum colour. The b* parameter may be used as an indicator for estimating carotenoid concentrations in colostrum and TM, particularly when assessed via transmittance spectroscopy.

Relationship between rumen microbiota and pregnancy toxemia in ewes.

Introduction: Pregnancy toxemia (PT) is a nutritional metabolic disease of ewes in late pregnancy. This study aimed to reveal the relationship between rumen microbiota and PT. Methods: We selected 10 healthy ewes (CON) and 10 pregnancy toxemia ewes (PT) at 135 days of gestation according to the blood ß-hydroxybutyrate (BHBA), glucose (Glu) concentrations and clinical symptoms. Blood and rumen fluid were collected before morning feeding to determine serum biochemical indices and rumen fermentation parameters. Total DNA of rumen fluid was extracted and the V3-V4 regions of 16S rRNA were amplified by PCR for high-throughput sequencing. Results: The results showed that the serum concentrations of Glu, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), uric acid (UA), creatinine (Cr), acetate, propionate, butyrate, and microbial crude protein (MCP) were decreased (p < 0.05) and the concentrations of BHBA, aspartate aminotransferase (AST), acetate to propionate ratio (A/P), and ammonia nitrogen (NH3-N)were higher (p < 0.05) in PT ewes than those in CON ewes. 16S rRNA analysis showed the differences of ß-diversity were observed in rumen microbiota between CON and PT ewes. At the phylum level, the relative abundance of Bacteroidota and Proteobacteria were higher (p < 0.01), while Firmicutes was lower (p < 0.01) in PT ewes. At the genus level, the relative Prevotella, Butyrivibrio, Ruminococcus, Lachnospiraceae_AC2044_group, Lachnospiraceae_XPB1014_group, Lachnospiraceae_ND3007_group, and Oribacterium were lower (p < 0.01) in PT ewes. Meanwhile, the relative abundance of Oribacterium, Butyrivibrio, Ruminococcus, and Lachnospiraceae_AC2044_group were positively correlated (p < 0.01) with Glu, INS, acetate, propionate, and butyrate, and negatively correlated (p < 0.01) with BHBA, P, GC, AST, and A/P. Discussion: In conclusion, the decrease of Oribacterium, Butyrivibrio, Ruminococcus, and Lachnospiraceae_AC2044_group in the rumen of PT ewes reduced the concentrations of volatile fatty acids (acetate, propionate, and butyrate) and serum Glu, and increased BHBA concentration, indicating that the differences in rumen bacteria genera were related to pregnancy toxemia of ewes.

Game changer for anaerobic fermentation of paper mulberry: Sucrose-loaded biochar enhancing microbial communities and lactic acid fermentation.

This study investigated biochar effects, either alone or combined with sucrose, on fermentation quality, microbial communities, and in vitro rumen digestion of anaerobic fermented paper mulberry. The biochar alkaline functional groups bind to lactic acid, reducing acid inhibition and promoting Lactiplantibacillus proliferation. Owing to the low sugar content of paper mulberry, lactic acid bacteria in the biochar group primarily underwent heterofermentation, resulting in the lowest lactic and highest acetic acid contents. Treated with sucrose-loaded biochar, the increased substrate supported homofermentation, leading to the highest lactic and lowest acetic acid contents, with a 15.0 % increase in lactic acid and a 22.2 % decrease in ammoniacal nitrogen compared with the control after 75 days. In vitro rumen tests showed that the biochar-sucrose group had the highest dry matter degradation rate (45.9 %) and a 24.2 % reduction in methane emissions. Concludingly, sucrose-loaded biochar is recommended as effective for lactic acid production under anaerobic conditions.

Oral swabs as a proxy for direct ruminal microbiome sampling in Holstein dairy cows is correlated with sample color.

Using oral swabs to collect the remnants of stomach content regurgitation during rumination in dairy cows can replicate up to 70% of the ruminal bacterial community, offering potential for broad-scale population-based studies on the rumen microbiome. The swabs collected from dairy cows often vary widely with respect to sample quality, likely due to several factors such as time of sample collection and cow rumination behavior, which may limit the ability of a given swab to accurately represent the ruminal microbiome. One such factor is the color of the swab, which can vary significantly across different cows. Here, we hypothesize that darker-colored swabs contain more rumen contents, thereby better representing the ruminal bacterial community than lighter-colored swabs. To address this, we collected oral swabs from 402 dairy cows and rumen samples from 13 cannulated cows on a research farm in Wisconsin, United States and subjected them to 16S rRNA sequencing. In addition, given that little is known about the ability of oral swabs to recapitulate the ruminal fungal community, we also conducted ITS sequencing of these samples. To correlate swab color to the microbiota we developed and utilized a novel imaging approach to colorimetrically quantify each swab from a range of light to dark. We found that swabs with increasing darkness scores were significantly associated with increased bacterial alpha diversity (p < 0.05). Lighter swabs exhibited greater variation in their community structure, with many identified amplicon sequence variants (ASVs) categorized as belonging to known bovine oral and environmental taxa. Our analysis of the fungal microbiome found that swabs with increasing darkness scores were associated with decreased alpha diversity (p < 0.05) and were also significantly associated with the ruminal solids fungal community, but not with the ruminal liquid community. Our study refines the utility of oral swabs as a useful proxy for capturing the ruminal microbiome and demonstrates that swab color is an important factor to consider when using this approach for documenting both the bacterial and fungal communities.

Performance, ruminal and fecal microbiome of lambs fed diets supplemented with probiotics.

The present study aimed to investigate the impact of adding two doses of a commercial probiotic on productive performance, ruminal and fecal microbiome in growing lambs. Forty-two Texel or Ile de France crossbred lambs aged 86.9 ± 8.0 days (body weight: 27.4 ± 3.7 kg) were distributed into three groups: basal diet without probiotic supplementation (CG); basal diet + 1 g/animal/day of probiotic (GP1) and basal diet + 5 g/animal/day of probiotic (GP5). The experimental period was 84 days. The weight was evaluated weekly and dry matter intake (DMI) and leftovers were measured daily. At the end of the experiment, lambs were slaughtered. Feces and rumen fluid were collected for microbiome analysis and rumen fragments for histological evaluation. The use of probiotics did not affect weight gain, but GP1 showed a higher silage and DMI intake than CG (p < 0.001). The CG had a greater thickness of keratinized epithelium and stratum corneum (< 0.001) than GP1 and GP5, and greater total papilla width (p = 0.039) than GP1. There was no difference in the general abundance in the rumen and fecal microbiomes. GP5 had a higher proportion of Azoarcus and Dialister taxa in the rumen fluid (p = 0.012 and p = 0.017, respectively) and higher proportion of Treponema and Fibrobacter taxa in the fecal microbiome (p = 0.015 and p = 0.026, respectively), whereas CG had a higher proportion of Anaeroplasma than the other groups (p = 0.032). These results demonstrated the benefits of probiotics for ruminal epithelium protection and microbial diversity. However, there was no effect on performance parameters.

Effects of supplementing rumen-protected arginine on performance of transition cows.

An experiment was conducted to determine the effects of supplementing rumen-protected arginine (RPA) on productive performance in dairy cows. One-hundred and 2 cows were blocked by parity and then by energy-corrected milk (ECM) yield. Within block, cows were randomly assigned to control (CON) that received 200 g/d of a mixture of hydrogenated soybean oil and heat-treated soybean meal to supply 30 g of metabolizable protein (MP), or 200 g/d of a product containing 30 g of metabolizable arginine (RPA), which increased the dietary arginine from 5.7 to 7.5% of the MP from 250 d of gestation to 21 d postpartum. After 21 d postpartum, cows were fed the same diet and data were collected until 84 d postpartum. Cows fed RPA produced an additional 2.5 kg of colostrum (5.3 vs. 7.8 ± 1.0 kg) and 220 g more immunoglobulin G (526 vs. 746 ± 93 g) than CON cows. Supplementing RPA increased the yields of milk (32.8 vs. 34.9 ± 1.0 kg/d), ECM (37.8 vs. 40.9 ± 1.2 kg/d), and milk total solids (4.48 vs. 4.86 ± 0.14 kg/d) in the first 21 DIM. The benefits of RPA extended beyond the period of supplementation, with a 6.4% increase in yield of ECM per kg of dry matter consumed in all cows (1.88 vs. 2.00 ± 0.05 kg/kg) and an increase in ECM yield, but only in parous cows (44.2 vs. 48.5 ± 1.5 kg/d). Feeding RPA increased the concentrations of urea N in plasma pre- (12.5 vs. 13.9 ± 0.4 mg/dL) and postpartum (11.6 vs. 13.2 ± 0.4 mg/dL), and in milk during the first 21 d postpartum (11.0 vs. 12.0 ± 0.3 mg/dL). Treatment did not affect the concentrations of AA in plasma prepartum, but feeding RPA tended to increase citrulline (72.5 vs. 77.5 ± 2.7 µM), whereas RPA either tended to decrease isoleucine (129.5 vs. 120.9 ± 5.7 µM) or decreased the concentrations of leucine (181.3 vs. 170.2 ± 6.4 µM) and valine (293.2 vs. 276.7 ± 10.4 µM) postpartum. Feeding RPA increased the relative expression of transcripts involved in AA transport (SLC38A4), urea cycle (ARG1), and gluconeogenesis (PC, PEPCK, and G6PC) in hepatic tissue. Feeding diets to supply additional arginine as RPA during the transition period benefited productive performance in dairy cows that extended beyond the period of supplementation despite minor changes in plasma AA concentrations.

Rosa roxburghii tratt residue: A novel feed resource for cattle indicated by the non-deleterious performance and blood metabolites.

Rosa roxburghii tratt residue (RRTR) is a regional and uncommon byproduct in Guizhou. Little information is available on whether RRTR can be used as feed for ruminants. In this study, the feasibility of using RRTR as a new feed resource for cattle was investigated by chemical composition analysis, in vitro gas production (Trial 1) and animal feeding experiments (Trial 2). In trial 1, compared to the commonly used fruit residues, RRTR had a proximate nutrient level; the in vitro gas production curve and dynamics fell within the normal range. In trial 2, 16 cattle were allocated to the control and treatment groups, with 8 replicates of 1 cattle each. Cattle in the control group were fed a basal diet without RRTR, while those in the treatment group were fed a diet containing 30% RRTR to replace 30% whole corn silage in basal diet. Feeding RRTR had little effect on the growth performance of the control and treatment cattle (P > 0.05). The feed-to-gain ratio was greater in the treatment group than in the control group throughout the trial period (P < 0.05). The plasma urea levels in the treatment group were lower (P < 0.05) than that in control group, and the levels of other plasma biochemical metabolites were not different between the two groups of cattle (P > 0.05). The in vivo rumen fermentation parameters did not differ between the control and treatment groups (P > 0.05). Our findings indicate that RRTR has a nutritional profile (crude protein, neutral detergent fiber, acid detergent fiber, and crude fiber) similar to that of commonly used fruit residues (such as apple, pineapple, and citrus residue et al.); improves plasma protein utilization efficiency; and has no negative impact on growth performance, albeit with limited effects on feed conversion; blood metabolites, and rumen fermentation parameters in cattle. Accordingly, we conclude, based on the above-mentioned result, that RRTR can serve as a novel feed alternative resource when considering the affordability and as a practical choice for low-cost diets for cattle.

Improved and easy method for long-term in vitro culture of rumen ciliates Dasytricha ruminantium.

The rumen ciliates are a diverse group of protozoa residing in the rumen of ruminant animals. They are primarily found in the orders Entodiniomorphida and Vestibuliferida, playing crucial roles in the digestion and breakdown of feed within the host's rumen, closely intertwined with the host's nutrient absorption. In vitro monocultures of representatives of rumen ciliates are important to better study them. So far, Entodinium caudatum and Epidinium caudatum, representatives of the order Entodiniomorphida, have been successfully cultivated as a monoculture in vitro. However, for the order Vestibuliferida, no representative species has been established a stable monoculture in vitro up to date, which hampers to study their physiology and metabolism. Therefore, we have developed a simple method for the in vitro cultivation of Dasytricha ruminantium, a representative rumen ciliate in the order Vestibuliferida. Utilizing an optimized culture medium with easily obtainable components, and the cultivation process is simple. This will facilitate further research in metabolism and other studies requiring large pure live materials.1.Filtration and separation for enriching D. ruminantium.2.A culture medium (DRM) suitable for the growth of D. ruminantium, with easily obtainable components.3.Simple cultivation process, facilitating the obtainment of a large number of monocultured D. ruminantium.

In vitro and ex vivo metabolism of chemically diverse fructans by bovine rumen Bifidobacterium and Lactobacillus species.

BACKGROUND: Inulin and inulin-derived fructooligosaccharides (FOS) are well-known prebiotics for use in companion animals and livestock. The mechanisms by which FOS contribute to health has not been fully established. Further, the fine chemistry of fructan structures from diverse sources, such as graminan-type fructans found in cereal crops, has not been fully elucidated. New methods to study fructan structure and microbial responses to these complex carbohydrates will be key for evaluating the prebiotic potency of cereal fructans found in cattle feeds. As the rumen microbiome composition is closely associated with their metabolic traits, such as feed utilization and waste production, prebiotics and probiotics represent promising additives to shift the microbial community toward a more productive state. RESULTS: Within this study, inulin, levan, and graminan-type fructans from winter wheat, spring wheat, and barley were used to assess the capacity of rumen-derived Bifidobacterium boum, Bifidobacterium merycicum, and Lactobacillus vitulinus to metabolize diverse fructans. Graminan-type fructans were purified and structurally characterized from the stems and kernels of each plant. All three bacterial species grew on FOS, inulin, and cereal crop fructans in pure cultures. L. vitulinus was the only species that could metabolize levan, albeit its growth was delayed. Fluorescently labelled polysaccharides (FLAPS) were used to demonstrate interactions with Gram-positive bacteria and confirm fructan metabolism at the single-cell level; these results were in agreement with the individual growth profiles of each species. The prebiotic potential of inulin was further investigated within naïve rumen microbial communities, where increased relative abundance of Bifidobacterium and Lactobacillus species occurred in a dose-dependent and temporal-related manner. This was supported by in situ analysis of rumen microbiota from cattle fed inulin. FLAPS probe derived from inulin and fluorescent in situ hybridization using taxon-specific probes confirmed that inulin interacts with Bifidobacteria and Lactobacilli at the single-cell level. CONCLUSION: This research revealed that rumen-derived Bifidobacteria and Lactobacilli vary in their metabolism of structurally diverse fructans, and that inulin has limited prebiotic potential in the rumen. This knowledge establishes new methods for evaluating the prebiotic potential of fructans from diverse plant sources as prebiotic candidates for use in ruminants and other animals.

Phenotypic traits related to methane emissions from Holstein dairy cows challenged by low or high forage proportion.

Limited literature is available identifying phenotypical traits related to enteric methane (CH4) production from dairy cows, despite its relevance in relation to breeding for animals with a low CH4 yield (g/kg DMI), and the derived consequences hereof. This study aimed to investigate the relationships between CH4 yield and different animal phenotypes when 16 2nd parity dairy cows, fitted with a ruminal cannula, were fed 2 diets differing in forage:concentrate ratio in a crossover design. The diets had either a low forage proportion (35% on DM basis, F35) or a high forage proportion (63% on DM basis, F63). Gas exchange was measured by means of indirect calorimetry. Spot samples of feces were collected, and indigestible NDF (INDF) was used as an internal marker to determine total-tract digestibility. In addition, ruminal evacuations, monitoring of chewing activity, determination of ruminal VFA concentration, analysis of relative abundance of methanogens, and measurement of liquid passage rate were performed. Statistical differences were analyzed by a linear mixed model with diet, days in milk, and period as fixed effects, and cow as random effect. The random cow estimates (RCE) were extracted from the model to get the Pearson correlations (r) between RCE of CH4 yield with RCE of all other variables measured, to identify possible phenotypes related to CH4 yield. Significant correlations were observed between RCE of CH4 yield and RCE of OM digestibility (r = 0.63) and ruminal concentration of valeric acid (r = -0.61), acetic acid (r = 0.54), ammonium (r = 0.55), and lactic acid (r = ‒0.53). Additionally, tendencies were observed for correlations between RCE of CH4 yield and RCE of H2 yield in g/kg DM (r = 0.47, P = 0.07), and ruminal isobutyric acid concentration (r = 0.43, P = 0.09). No correlations were observed between RCE of CH4 yield and RCE of ruminal pool sizes, milk data, urinary measurements, or chewing activity. Cows had a lower DMI and ECM, when they were fed F63 compared with F35. Cows fed F63 had higher NDF digestibility, CH4 emissions (g/d, g/kg of DMI, and g/kg of ECM), ruminal concentration of acetic acid, ruminal pH, degradation rate of digestible NDF (DNDF, %/h), and longer rumen retention time (h). Also, rumination and total chewing time (min/kg DMI) were higher for cows fed F63. The results in the present study emphasize the positive relation between cow's ability to digest OM and their CH4 emissions. The derived consequences of breeding for lower CH4 emission might be cows with lower ability to digest OM, but more studies are warranted for further documentation of this relationship.

Insight into the differences in meat quality among three breeds of sheep on the Qinghai-Tibetan plateau from the perspective of metabolomics and rumen microbiota.

Mutton is one of the most popular meats among the general public due to its high nutritional value. This study evaluated the differences in meat quality among Chaka (CK), Black Tibetan (BT) and Oula (OL) sheep and investigated the metabolic mechanisms affecting meat quality using targeted and untargeted metabolomics and 16S rRNA. The results showed that the meat quality of CK sheep was superior to that of BT and OL sheep in terms of meat color, muscle fiber characteristics and nutritional quality. Pseudobutyrivibrio, Alloprevotella, Methanobrevibacter, unidentified_Christensenellaceae, and unidentified_Bacteroidales were key microbes involved in regulating meat color, muscle fiber characteristics, amino acid and fatty acid content. Protein digestion/absorption, pentose phosphate metabolism, carbon metabolism, and glyoxylate and dicarboxylate metabolism were important metabolic pathways involved in meat quality regulation. Our study is important for the development of sheep breeding strategy and sheep meat industry in Qinghai-Tibetan Plateau.

Dietary secoisolariciresinol diglucoside crude extract improves growth through modulating rumen bacterial community and epithelial development in lambs.

BACKGROUND: Flaxseed lignans, types of polyphenolic compounds, primarily consist of secoisolariciresinol diglucoside (SDG). Natural plant extracts are becoming increasingly important as feed for ruminant animals. An underutilized plant bioactive component, SDG shows promising benefits for young ruminant production. The objective of this study was to assess the impact of SDG on rumen fermentation using an in vitro rumen simulation technology. Additionally, we tested the effects of SDG (0.20 g kg-1 body weight) on rumen development and production performance of lambs in a production setting. RESULTS: The in vitro addition of 100 mg L-1 SDG demonstrated significant regulatory effects, with a notable decrease in the acetate/propionate ratio (P < 0.05). Feeding trials revealed that SDG significantly increased average daily feed intake and average daily weight gain (P < 0.05), and reduced the acetate/propionate ratio (P < 0.05). This led to a significant increase in the relative abundance of Eubacterium ruminantium (P = 0.038) and Butyrivibrio (P = 0.002). Furthermore, it promoted rumen development and upregulated the relative expression of mRNA of Cyclin E1 and CDK2 in rumen epithelial cells (P < 0.05). CONCLUSION: The SDG extract optimizes the composition of rumen microbiota and the development of rumen epithelial cells, promoting the growth of pre-weaning lambs. The SDG additive exhibits potential as a novel growth promoter for ruminant animals, offering a promising solution for sustainable livestock production. © 2024 Society of Chemical Industry.

Multi-omics analysis reveals the effects of host-rumen microbiota interactions on growth performance in a goat model.

The growth rate of young ruminants has been associated with production performance in later life, with recent studies highlighting the importance of rumen microbes in supporting the health and growth of ruminants. However, the specific role of rumen epithelium bacteria and microbiota-host interactions in influencing the early life growth rate of ruminants remains poorly understood. In this study, we investigated the rumen fermentation pattern, microbiota characteristics, and global gene expression profiles of the rumen epithelium in 6-month-old goats with varying growth rates. Our results showed that goats with high average daily gain (HADG) exhibited higher rumen propionate concentrations. Goats with low average daily gain (LADG) had the higher relative abundances of rumen epithelium bacteria genera U29-B03 and Quinella, while exhibiting a lower relative abundance of Lachnospiraceae UCG-009. In the rumen fluid, the relative abundances of bacteria genus Alloprevotella were lower and Desulfovibrio were higher in LADG goats compared to HADG goats. Additionally, the relative abundance of fungal genus Symmetrospora was lower in LADG goats compared to HADG goats. Transcriptome analysis showed that 415 genes were differentially expressed between LADG and HADG goats, which were enriched in functions related to cell junction and cell adhesion, etc. Correlation analysis revealed that rumen epithelium bacteria genera UCG-005 and Candidatus Saccharimonas were negatively associated, while Lachnospiraceae NK3A20 group and Oscillospiraceae NK4A214 group were positively associated with average daily gain (ADG) and genes related to barrier function. The rumen fluid bacteria genus Alloprevotella was positively correlated, while Desulfovibrio was negatively correlated with rumen propionate and ammoniacal nitrogen (NH3-N) concentrations, as well as genes related to barrier function and short chain fatty acids (SCFAs) transport. In summary, our study reveals that the higher ruminal fermentation efficiency, improved rumen epithelial barrier functions, and enhanced SCFAs transport in HADG goats could be attributed to the rumen microbiota, particularly the rumen epithelium bacteria, such as Lachnospiraceae and Oscillospiraceae NK4A214 group.

Effects of forage feeding level on ruminal pH and metabolic adaptation of the rumen epithelium in pre-weaned Jersey calves.

The objective of this study was to determine the effect of limiting forage provision in pre-weaned calves on ruminal pH and short chain fatty acid (SCFA) transport capacity during the pre-weaning period. Twelve Jersey bull calves (age = 1.9 ± 0.8 d) were housed individually on sand. All calves were fed milk replacer at 1,200 g/d and texturized grain-based starter ad libitum from birth. Calves were randomly assigned one of two treatments: ad libitum forage (ALF) or limited forage provision, where forage was limited to 90 g/d as-fed (LFP). Individual feed intake was recorded daily, calf weights, and jugular blood samples were collected weekly. Once calves consumed 680 g/d of calf starter, ruminal pH was measured for seven days after which calves were humanely killed and rumen fluid sampled. During the pre-weaning period, starter intake, feed efficiency, plasma glucose and ß-hydroxybutyrate (BHB) concentration, SCFA concentration, average daily gain, and body weight were not different between treatments. Forage intake for ALF calves was greater than LFP beginning at wk 9 (255 ± 34 vs. 71 ± 40 g/d, respectively). Compared to ALF, LFP decreased mean ruminal pH (6.38 ± 0.16 vs. 5.98 ± 0.23) and duration of time where rumen pH was below 5.8 (796 ± 145 vs. 261 ± 133 min/d). Epithelial markers of SCFA transport and cell homeostasis (MCT1, NBC1, NHE3) were not affected by treatment. In conclusion, incidence of sub-acute ruminal acidosis in limited forage-fed calves did not have the same effects on intake and nutrient transporters seen in adult cows.

Multi-omics revealed the mechanism of feed efficiency in sheep by the combined action of the host and rumen microbiota.

This study was conducted to investigate potential regulatory mechanisms of feed efficiency (FE) in sheep by linking rumen microbiota with its host by the multi-omics analysis. One hundred and ninety-eight hybrid female sheep (initial body weight = 30.88 ± 4.57 kg; 4-month-old) were selected as candidate sheep. Each test sheep was fed in an individual pen for 60 days, and the residual feed intake (RFI) was calculated. The ten candidate sheep with the highest RFI were divided into the Low-FE group, and the ten with the lowest RFI were divided into the High-FE group, all selected for sample collection. The RFI, average daily gain and average daily feed intake were highly significantly different between the two experimental groups (P < 0.05). Compared with Low-FE group, the insulin-like growth factor-1 and very low-density lipoprotein in serum and the propionate in rumen significantly increased in High-FE group (P < 0.01), but the acetate:propionate ratio in rumen significantly decreased in High-FE group (P = 0.034). Metagenomics revealed Selenomonas ruminantium, Selenomonas sp. and Faecalibacterium prausnitzi i were key bacteria, and increased abundance of the genes encoding the enzymes for cellulose degradation and production of propionate in High-FE group. The results of proteomics and section showed the rumen papilla length (P < 0.001) and expression of carbonic anhydrase and Na+/K+-ATPase were significantly higher in High-FE group (P < 0.05). On the other hand, the acetyl-CoA content significantly increased in the liver of High-FE group (P = 0.002). The relative expression levels of insulin-like growth factor-1 and apolipoprotein A4 genes were significantly up-regulated in the liver of High-FE group (P < 0.01), but relative expression level of monoacylglycerol O-acyltransferase 3 gene was significantly down-regulated (P = 0.037). These findings provide the mechanism by which the collaborative interaction between rumen microbiota fermentation and host uptake and metabolism of fermentation products impacts feed efficiency traits in sheep.