Effect of protein supplementation on ruminal parameters and microbial community fingerprint of Nellore steers fed tropical forages

In tropical regions, protein supplementation is a common practice in dairy and beef farming. However, the effect of highly degradable protein in ruminal fermentation and microbial community composition has not yet been investigated in a systematic manner. In this work, we aimed to investigate the impact of casein supplementation on volatile fatty acids (VFA) production, specific activity of deamination (SAD), ammonia concentration and bacterial and archaeal community composition. The experimental design was a 4×4 Latin square balanced for residual effects, with four animals (average initial weight of 280±10 kg) and four experimental periods, each with duration of 29 days. The diet comprised Tifton 85 (Cynodon sp.) hay with an average CP content of 9.8%, on a dry matter basis. Animals received basal forage (control) or infusions of pure casein (230 g) administered direct into the rumen, abomasum or divided (50 : 50 ratio) in the rumen/abomasum. There was no differences (P>0.05) in ruminal pH and microbial protein concentration between supplemented v. non-supplemented animals. However, in steers receiving ruminal infusion of casein the SAD and ruminal ammonia concentration increased 33% and 76%, respectively, compared with the control. The total concentration of VFA increased (P<0.05) in steers receiving rumen infusion of casein. SAD and the microbial protein concentration did not vary significantly among treatments during the feeding cycle, but mean SAD values were greater in steers supplemented in the rumen and rumen/abomasum. Ruminal ammonia concentration was positively correlated with SAD in animals receiving ruminal infusion of casein. Polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE) analysis revealed low similarity between treatments, animals and time of sample collection. Richness analysis and determination of the Shannon–Wiener index indicated no differences (P>0.05) in species richness and diversity of γ-proteobacteria, firmicutes and archaea between non-supplemented Nellore steers and steers receiving casein supplementation in the rumen. However, species richness and the Shannon–Wiener index were lower (P<0.05) for the phylum bacteroidetes in steers supplemented with casein in the rumen compared with non-supplemented animals. Venn diagrams indicated that the number of unique bands varied considerably among individual animals and was usually higher in number for non-supplemented steers compared with supplemented animals. These results add new knowledge about the effects of ruminal and postruminal protein supplementation on metabolic activities of rumen microbes and the composition of bacterial and archaeal communities in the rumen of steers.     

Effect of the supplementation of a high-concentrate diet with sunflower and fish oils on ruminal fermentation in sheep

This study was conducted to test the hypothesis that the supplementation of a high-concentrate diet with lipids, reportedly a good strategy for improving the nutritional value of ruminant-derived products, may not necessarily be associated with detrimental effects on ruminal fermentation in sheep. Four ruminally cannulated adult ewes were fed a high-concentrate diet, with no oil (Control diet), for a 14-day adaptation period. Afterwards, they were fed the same basal diet but supplemented with sunflower oil [20 g/kg fresh matter (FM)] and fish oil (10 g/kg FM) (SOFO diet) for a further 11 days, to investigate the impact of the addition of oils on the ruminal fermentation of the diet. On days 0 (Control), 3 and 10 of the experimental period rumen fluid was sampled at 0, 1.5, 3, 6 and 9 h after the morning feeding, for analysis of pH, and ammonia, lactate and total volatile fatty acid (VFA) concentrations. Alfalfa hay was incubated in situ, using the nylon bag technique, for 12 and 24 h to examine the effect of oil supplementation on ruminal disappearance of dry matter (DM), crude protein (CP) and neutral-detergent fibre (NDF). On days 0 and 11, rumen fluid was collected just before the morning feeding and used to incubate alfalfa hay and the Control and SOFO diets by means of the in vitro gas production technique. The mean concentrations of acetate (87.8 mmol/L vs. 73.7 mmol/L) and butyrate (21.2 mmol/L vs. 17.7 mmol/L) were reduced by oil supplementation (P < 0.05) and the total VFA showed a tendency (P = 0.098) to be lower with the SOFO diet (139.0 mmol/L vs. 122.1 mmol/L). However, none of the other in vivo ruminal fermentation parameters were affected by the treatment (P > 0.10). The oil supplementation affected neither in situ rumen disappearance of DM, CP and NDF of alfalfa hay, nor rates of gas production (P > 0.10). On the other hand, a little, but significant reduction in cumulative gas production was observed when the experimental diets were incubated with rumen fluid derived from animals fed the oil-rich diet (P < 0.05).Overall, the results suggest that the supplementation of high-concentrate diets with sunflower oil (20 g/kg FM) plus fish oil (10 g/kg FM) had little effect on ruminal fermentation and therefore its use to improve the nutritional value of ruminant-derived products cannot be precluded.     

Effects of species-diverse high-alpine forage on in vitro ruminal fermentation when used as donor cow's feed or directly incubated

Alpine forages are assumed to have specific effects on ruminal digestion when fed to cattle. These effects were investigated in an experiment from two perspectives, either by using such forages as a substrate for incubation or as feed for a rumen fluid donor cow. In total, six 24-h in vitro batch culture runs were performed. Rumen fluid was collected from a non-lactating donor cow after having grazed pastures at ∼2000 m above sea level for 2, 6 and 10 weeks. These ‘alpine runs’ were compared with three lowland samplings from before and 2 and 6 weeks after the alpine grazing where a silage–concentrate mix was fed. In each run, nine replicates of four forages each were incubated. These forages differed in type and origin (alpine hay, lowland ryegrass hay, grass–maize silage mix, pure hemicellulose) as well as in the content of nutrients. Concentrations of phenolic compounds in the incubated forages were (g/kg dry matter (DM)): 20 (tannin proportion: 0.47), 8 (0.27), 15 (0.52) and 0 (0), respectively. Crude protein was highest in the silage mix and lowest with hemicellulose, whereas the opposite was the case for fiber. The total phenol contents (g/kg DM) for the high altitude and the lowland diet of the donor cow were 27 (tannins: 0.50 of phenols) and 12 (0.27), respectively. Independent of the origin of the rumen fluid, the incubation with alpine hay decreased (P < 0.05) bacterial counts, fermentation gas amount, volatile fatty acid (VFA) production as well as ammonia and methane concentrations in fermentation gas (the latter two being not lower when compared with hemicellulose). Alpine grazing of the cow in turn increased (P < 0.001) bacterial counts and, to a lesser extent, acetate proportion compared with lowland feeding. Further, alpine grazing decreased protozoal count (P < 0.05) and VFA production (P < 0.001) to a small extent, whereas methane remained widely unchanged. There were interactions (P < 0.05) between forage type incubated and feeding period of the donor cow in protozoal counts, acetate:propionate ratio, fermentation gas production and its content of methane, in vitro organic matter digestibility and metabolizable energy. Although increased phenolic compounds were the most consistent common property of the applied alpine forages, a clear attribution to certain effects was not possible in this study. As a further result, adaptation (long-term for donor cow, short term for 24 h incubations) appears to influence the expression of alpine forage effects in ruminal fermentation.     

Impact of subacute ruminal acidosis on the diversity of liquid and solid-associated bacteria in the rumen of goats

This study was aimed to investigate the impact of subacute ruminal acidosis (SARA) on the diversity of liquid (LAB) and solid-associated bacteria (SAB) following high-grain feeding. Six ruminally cannulated goats were divided into two groups: one group was fed a hay diet (COD), and the other group was fed a high grain diet (SAID). Rumen liquids and rumen solids were sampled after 2 weeks adaption. SARA was diagnosed with a pH below 5.8 for 8 h. SAID decreased ruminal pH (P < 0.001) and increased the acetate (P = 0.017), propionate (P = 0.001), butyrate (P < 0.001) and total volatile fatty acid (P < 0.001) concentration in rumen compared with the COD. Denaturing gradient gel electrophoresis fingerprints analysis revealed a clear separation between both the diet and the fraction of rumen digesta in bacterial communities. Pyrosequencing analysis showed that the proportion of phylum Bacteroidetes in the SAID-LAB and SAID-SAB communities was less than in the COD group, whereas the SAID group had a greater percentage of Firmicutes in both the LAB and SAB libraries. UniFrac analyses and a Venn diagram revealed a large difference between the two diets in the diversity of rumen bacterial communities. Overall, our findings revealed that SARA feeding did alter the community structure of rumen liquids and rumen solids. Thus, manipulation of dietary factors, such as ratio of forage to concentrate may have the potential to alter the microbial composition of rumen liquid and rumen solid.     

Effect of a controlled-release urea supplement on rumen fermentation in sheep fed a diet of sugar cane tops (Saccharum officinarum), corn stubble (Zea mays) and King grass (Pennisetum purpureum)

Four cannulated sheep were used to study ruminal fermentation of a diet consisting of 60% sugar cane tops (Saccharum officinarum), 30% corn stubble (Zea mays), 10% King grass (Pennisetum purpureum) and 0% (control), 10, 20 or 30% controlled-release urea supplement (CRUS) (diets 1, 2, 3 and 4, respectively). Average ruminal pH did not differ among diets (P>0.05), but during the first 6 h of sampling tended to be higher for CRUS diets. Ammonia concentrations were higher (P<0.01) in all treatments over controls, indicating microbial protein generation. Acetic acid production (mM/1) decreased (P<0.05), propionic acid increased (P<0.05), while butyric acid production did not differ among CRUS diets and controls (P>0.05). Total amounts of ruminal VFA were lowest (P<0.01) in controls, while CRUS diets produced more of these energy sources. Supplementation of the high fiber diets with 10, 20 or 30% CRUS increasingly improved rumen fermentation, ammonia supply and VFA production. The results show that low quality forages (up to 70% DMI) can be used efficiently by sheep when conditions for ruminal microorganism are improved with a controlled-release urea supplement.     

High-grain diet feeding altered the composition and functions of the rumen bacterial community and caused the damage to the laminar tissues of goats

In the current intensive production system, ruminants are often fed high-grain (HG) diets. However, this feeding pattern often causes rumen metabolic disorders and may further trigger laminitis, the exact mechanism is not clear. This study investigated the effect of HG diet feeding on fermentative and microbial changes in the rumen and on the expression of pro-inflammatory cytokines and matrix metalloproteinases (MMPs) in the lamellar tissue. In all, 12 male goats were fed a hay diet (0% grain; n=6) or an HG diet (56.5% grain; n=6). On day 50 of treatment, samples of blood, rumen content, and lamellar tissue of hooves of goats were collected. The data showed that compared with the hay group, HG-fed goats had lower (P<0.05) rumen pH but higher (P<0.05) total volatile fatty acids and lactate in the rumen and higher (P<0.05) lipopolysaccharide (LPS) levels in the rumen and blood. HG diet feeding altered the composition of rumen bacterial community, and correspondingly, the results suggested that their functions in the HG group were also altered. HG diet feeding increased (P<0.05) the expression of interleukin-1β, interleukin-6, tumour necrosis factor-α and MMP-2 mRNA in the lamellar tissues compared with the hay group. Correlation analysis indicated that the expression of pro-inflammatory cytokines were positively correlated with MMP-2 expression in lamellar tissues. Overall, these results revealed that HG feeding altered the patterns of rumen fermentation and the composition and functions of rumen bacterial community, and lead to higher levels of LPS in the peripheral blood, and further activated the inflammatory response in lamellar tissues, which may progress to the level of laminar damage.     

Rubber seed oil and flaxseed oil supplementation alter digestion,ruminal fermentation and rumen fatty acid profile of dairy cows

Rubber seed oil (RO) that is rich in polyunsaturated fatty acids (FA) can improve milk production and milk FA profiles of dairy cows; however, the responses of digestion and ruminal fermentation to RO supplementation in vivo are still unknown. This experiment was conducted to investigate the effect of RO and flaxseed oil (FO) supplementation on nutrients digestibility, rumen fermentation parameters and rumen FA profile of dairy cows. Forty-eight mid-lactation Holstein dairy cows were randomly assigned to one of four treatments for 8 weeks, including basal diet (CON) or the basal dietary supplemented with 4% RO, 4% FO or 2% RO plus 2% FO on a DM basis. Compared with CON, dietary oil supplementation improved the total tract apparent digestibility of DM, neutral detergent fibre and ether extracts ( P < 0.05). Oil treatment groups had no effects on ruminal digesta pH value, ammonia N and microbial crude protein ( P > 0.05), whereas oil groups significantly changed the volatile fatty acid (VFA) profile by increasing the proportion of propionate whilst decreasing total VFA concentration, the proportion of acetate and the ratio of acetate to propionate ( P < 0.05). However, there were no differences in VFA proportions between the three oil groups (P > 0.05). In addition, dietary oil supplementation increased the total unsaturated FA proportion in the rumen by enhancing the proportion of trans-11 C18:1 vaccenic acid (VA), cis-9, trans-11 conjugated linoleic acid (CLA) and α-linolenic acid (ALA) ( P < 0.05). These results indicate that dietary supplementation with RO and FO could improve nutrients digestibility, ruminal fermentation and ruminal FA profile by enhancing the VA, cis-9, trans-11 CLA and ALA composition of lactating dairy cows. These findings provide a theoretical basis for the application of RO in livestock production.     

Associations of rumen parameters with feed efficiency and sampling routine in beef cattle

Characterizing ruminal parameters in the context of sampling routine and feed efficiency is fundamental to understand the efficiency of feed utilization in the bovine. Therefore, we evaluated microbial and volatile fatty acid (VFA) profiles, rumen papillae epithelial and stratum corneum thickness and rumen pH (RpH) and temperature (RT) in feedlot cattle. In all, 48 cattle (32 steers plus 16 bulls), fed a high moisture corn and haylage-based ration, underwent a productive performance test to determine residual feed intake (RFI) using feed intake, growth, BW and composition traits. Rumen fluid was collected, then RpH and RT logger were inserted 5.5±1 days before slaughter. At slaughter, the logger was recovered and rumen fluid and rumen tissue were sampled. The relative daily time spent in specific RpH and RT ranges were determined. Polynomial regression analysis was used to characterize RpH and RT circadian patterns. Animals were divided into efficient and inefficient groups based on RFI to compare productive performance and ruminal parameters. Efficient animals consumed 1.8 kg/day less dry matter than inefficient cattle (P⩽0.05) while achieving the same productive performance (P⩾0.10). Ruminal bacteria population was higher (P⩽0.05) (7.6×10¹¹ v. 4.3×10¹¹ copy number of 16S rRNA gene/ml rumen fluid) and methanogen population was lower (P⩽0.05) (2.3×10⁹ v. 4.9×10⁹ copy number of 16S rRNA gene/ml rumen fluid) in efficient compared with inefficient cattle at slaughter with no differences (P⩾0.10) between samples collected on-farm. No differences (P⩾0.10) in rumen fluid VFA were also observed between feed efficiency groups either on-farm or at slaughter. However, increased (P⩽0.05) acetate, and decreased (P⩽0.05) propionate, butyrate, valerate and caproate concentrations were observed at slaughter compared with on-farm. Efficient had increased (P⩽0.05) rumen epithelium thickness (136 v. 126 µm) compared with inefficient cattle. Efficient animals also spent 318% and 93.2% more time (P⩽0.05) in acidotic (4.14% v. 1.30%) (pH⩽5.6) and optimal (5.6<pH<6.0) (8.53% v. 4.42%) RpH range compared with inefficient cattle. The circadian patterns revealed lower (P⩽0.05) RpH and no differences (P⩾0.10) in RT pre-, during, and post-prandial periods in efficient compared with inefficient cattle. In essence, superior feed efficiency in cattle seems linked to rumen features consistent with improved efficiency of feed utilization. Microbial abundance, rumen epithelial histomorphology, and RpH, may serve as indicators for feed efficiency in cattle. The divergences of assessments made on-farm and at slaughter should be considered in the development of proxies for feed efficiency.     

Effects of an artificial hay aroma and compound feed formulation on feed intake pattern,rumen function and milk production in lactating dairy cows

The Kempen system is a dairy feeding system in which diet is provided in the form of a compound feed (CF) and hay offered ad libitum. Ad libitum access to CF and hay allows cows in this system to achieve a high DM intake (DMI). Out of physiological concerns, the voluntary hay intake could be increased and the consumption pattern of CF could be manipulated to maintain proper rumen functioning and health. This study investigated the effects of an artificial hay aroma and CF formulation on feed intake pattern, rumen function and milk production in mid- to late-lactating dairy cows. Twenty Holstein–Friesian cows were assigned to four treatments in a 4 × 4 Latin square design. Diet consisted of CF and grass hay (GH), fed separately, and both offered ad libitum, although CF supply was restricted in maximum meal size and speed of supply by an electronic system. Treatments were the combination of two CF formulations – high in starch (CHS) and fibre (CHF); and two GH – untreated (UGH) and the same hay treated with an artificial aroma (TGH). Meal criteria were determined using three-population Gaussian–Gaussian–Weibull density functions. No GH × CF interaction effects on feed intake pattern characteristics were found. Total DMI and CF intake, but not GH intake, were greater (P < 0.01) in TGH treatment, and feed intake was not affected by type of CF. Total visits to feeders per day, visits to the GH feeder, visits to the CF feeder and CF eating time (all P < 0.01) were significantly greater in cows fed with TGH. Meal frequency, meal size and meal duration were unaffected by treatments. Cows fed CHF had a greater milk fat (P = 0.02), milk urea content (P < 0.01) and a greater milk fat yield (P < 0.01). Cows fed TGH had a greater milk lactose content and lactose yield (P < 0.05), and milk urea content (P < 0.01). Cows fed TGH had smaller molar proportions of acetic acid and greater molar proportions of propionic acid compared with UGH. In conclusion, treatment of GH with an artificial aroma increased CF intake and total DMI, but did not affect hay intake. Additionally, GH treatment increased the frequency of visits to both feeders, and affected rumen volatile fatty acid profile. Type of CF did not affect meal patterns, ruminal pH, nor fermentation profiles.     

Effects of monensin on volatile fatty acid metabolism in periparturient dairy cows using compartmental analysis

Eight multiparous periparturient Holstein cows fitted with ruminal cannulas were used in a split plot design to evaluate effects of monensin on ruminal volatile fatty acid (VFA) metabolism. Diets were supplemented with 300 mg/day of monensin, or no monensin, both prepartum and postpartum. Isotopic tracers, Na-1-¹³C-acetate (Ac), Na-1-¹³C-propionate (Pr), or Na-1-¹³C-butyrate (Bu) were used as markers to describe VFA kinetics in the rumen. The Windows version of SAAM software (WinSAAM) was used to develop a steady state VFA model. A 9-compartment model was adequate to comprehensively describe ruminal VFA metabolism. The main VFA compartments consisted of Ac, Pr and Bu. The model estimated lower Bu and Ac interconversions with monensin, postpartum (Bu to Ac; 0.14 versus 0.12; P=0.04, and Ac to Bu; 0.32 versus 0.25; P=0.11) compared to when measured prepartum. Results demonstrate that dilution studies employing stable isotopes of VFA can be used to provide information on VFA metabolism of the periparturient dairy cow. A time frame of 320 min of labeled VFA infusion employing a single injection allows accurate quantification of VFA metabolism in the rumen. Compartmental kinetic analysis of major VFA in the rumen indicate that monensin reduced about 0.125 the portion of the Ac that contributes to Bu by reducing movements of Bu originated carbons to the Ac pool. Monensin may affect certain biochemical pathways of interconversion of Bu and Ac in the rumen. Propionate kinetic data suggests that Pr behaves as a single pool in the rumen. Monensin did not affect Pr production in the rumen suggesting that monensin improves the metabolic status of the transition cow in a way other than increasing Pr production in the rumen.     

Nutritional characterization of Mucuna pruiriens: 2. In vitro ruminal fluid fermentability of Mucuna pruriens,Mucunal-dopa and soybean meal incubated with or without l-dopa

Three in vitro experiments were conducted to determine the rumen fermentability of Mucuna (M) pruriens (24 g 3,4-dihydroxy-l-phenylalanine (l-dopa)/kg dry matter (DM) and soybean meal treated with (SBD) or without (SB) 138 g l-dopa/kg DM). Additional objectives were to determine if l-dopa inhibits rumen fermentation, and if ruminal microbes can adapt to l-dopa or M. In Experiment 1, ground (1 mm) substrates were incubated in triplicate at 38 °C in 9 ml nutrient media and 1 ml rumen fluid in a series of six, 48 h, consecutive batch cultures. The first culture was inoculated with rumen fluid from two donor cows. Subsequent cultures were inoculated with fluid (1 ml) from the previous culture. The DM digestibility (DMD, 616 g/kg vs. 540 g/kg; P<0.01) and gas production (51.7 ml/g vs. 44.2 ml/g DM; P<0.05) were higher from fermentation of M versus SB but similar for SB and SBD (540 g/kg vs. 554 g/kg and 44.2 ml/g DM vs. 43.5 ml/g DM, respectively). The slopes of the relationships between DMD (g/kg) or gas production (ml/g DM) and fermentation period were not reduced by fermenting M (−0.014 DMD slope; 2.28 gas production slope) or SBD (−0.014 DMD slope; 0.459 gas production slope), instead of SB (−0.002 DMD slope; 1.039 gas production slope), indicating microbial adaptation to M and SBD. Total volatile fatty acid concentration (VFA; 53.7, 54.9 and 54.9 mmol/l) and molar proportions of VFA were similar among substrates. Gas production kinetics of M versus SB (Experiment 2), and SB versus SBD (Experiment 3) were also measured after substrates were incubated in triplicate in buffered rumen fluid for 24 h using a non-linear exponential model to fit the data. Residual l-dopa was measured after separate fermentation of substrates in triplicate for 0, 4, 8, 16 and 24 h. Fermentation of M versus SB produced more (P<0.05) gas (250 ml/g vs. 100 ml/g DM) and total VFA (203 mmol/l vs. 180 mmol/l) and a lower (P<0.05) acetate:propionate ratio (1.35 vs. 1.87; P<0.05). Adding l-dopa to SB increased (P<0.01) gas production (92 ml/g DM vs. 200 ml/g DM), and total VFA concentration (132 mmol/l vs. 188 mmol/l), but reduced (P<0.05) gas production rate (0.08 ml/h vs. 0.05 ml/h). The concentration of l-dopa in fermented M and SBD decreased by 53 and 47%, respectively during fermentation. In conclusion, M was more fermented than SB and degradation of l-dopa during ruminal fermentation and microbial adaptation to l-dopa were confirmed. Adding l-dopa to SB did not impair ruminal fermentation.     

Effect of High-Dose Nano-selenium and Selenium–Yeast on Feed Digestibility, Rumen Fermentation, and Purine Derivatives in Sheep

The aim of this study was to evaluate the effect of nano-selenium (NS) and yeast?Cselenium (YS) supplementation on feed digestibility, rumen fermentation, and urinary purine derivatives in sheep. Six male ruminally cannulated sheep, average 43.32?±?4.8?kg of BW, were used in a replicated 3?×?3 Latin square experiment. The treatments were control (without NS and YS), NS with 4?g nano-Se (provide 4?mg Se), and YS with 4?g Se-yeast (provide 4?mg Se) per kilogram of diet dry matter (DM), respectively. Experimental periods were 25?days with 15?days of adaptation and 10?days of sampling. Ruminal pH, ammonia N concentration, molar proportion of propionate, and ratio of acetate to propionate were decreased (P?<?0.01), and total ruminal VFA concentration was increased with NS and YS supplementation (P?<?0.01). In situ ruminal neutral detergent fiber (aNDF) degradation of Leymus chinensis (P?<?0.01) and crude protein (CP) of soybean meal (P?<?0.01) were significantly improved by Se supplementation. Digestibilities of DM, organic matter, crude protein, ether extract, aNDF, and ADF in the total tract and urinary excretion of purine derivatives were also affected by feeding Se supplementation diets (P?<?0.01). Ruminal fermentation was improved by feeding NS, and feed conversion efficiency was also increased compared with YS (P?<?0.01). We concluded that nano-Se can be used as a preferentially available selenium source in ruminant nutrition.     

A rapid shift to high-grain diet results in dynamic changes in rumen epimural microbiome in sheep

The rapid shift to high-grain (HG) diets in ruminants can affect the function of the rumen epithelium, but the dynamic changes in the composition of the epithelium-associated (epimural) bacterial community in sheep still needs further investigation. Twenty male lambs were randomly allocated to four groups (n = 5). Animals of the first group received hay diet and represented a control group (CON). Simultaneously, animals in the other three groups (HG groups) were rapidly shifted to an HG diet (60% concentrate)which continued for 7 (HG7), 14 (HG14) and 28 (HG28) days, correspondingly. Results showed that ruminal pH dramatically decreased due to the rapid shift to the HG diet (P <0.001), while, the concentrations of butyrate (P <0.001), lactate (P = 0.001), valerate (P = 0.008) and total volatile fatty acids (P = 0.001) increased. Diversity estimators showed a dramatic decrease after the shift without recovering as the HG feeding continued. The principal coordinates analysis showed that CON group clustered separately from all HG groups with the presence of significant difference only between HG7 and HG28 (P = 0.034). The non-parametric multivariate analysis (npmv R-package) deduced that the primary significant differences in phyla and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt)-predicted Kyoto Encyclopedia of Genes and Genomes (KEGGs) was attributed mainly to the diet composition (P <0.001, P = 0.001) compared to its application period (P = 0.140, 0.545) which showed a significant effect only on the genus (P = 0.001) and the operational taxonomic units (OTUs) level (P = 0.011). The Kruskal–Wallis test deduced that six phyla showed a significant effect due to the shift in diet composition. At the genus level, HG feeding altered the abundance of 12 taxa, four of which showed a significant variation due to the duration of the HG diet application. Similarly, we found that 21 OTUs showed significant variations due to the duration of the HG diet application. Furthermore, the genes abundance predicted by PICRUSt revealed that the HG feeding significantly affected seven metabolic pathways identified in the KEGG. Particularly, the abundance of gene families associated with carbohydrates metabolism were significantly higher in HG feeding groups (P = 0.027). Collectively, these results revealed that the rapid transition to an HG diet causes dramatic alterations in ruminal fermentation and the composition and function of ruminal epithelium-associated microbiome in sheep, while, the duration of the HG diet application causes drastic alterations to the abundance of some species.     

Digesta characteristics of dorsal,middle and ventral rumen of cows fed with different hay qualities and concentrate levels

The influence of fibre content of hay (H) and concentrate level (C) on local differences in the composition of ruminal digesta (ratio of solid to fluid digesta, DM, NDF, ADF and ADL content), particle size (MPL), specific gravity (SG) and fermentation (pH and concentrations of SCFA and bicarbonate) have been tested on two ruminally cannulated Friesian cows (520?kg BW) which were fed restricted, using individual cows as experimental units. Digesta samples were collected via cannula from three rumen layers: 5 to 10?cm (top) and 25?–?35?cm beneath the top of the particle mat (middle) and 5?–?10?cm above the rumen floor (bottom). For a main plot treatment (H·C), repeated samples were collected at four time intervals (1?h before and 2, 5 and 10?h after morning feeding) on each of two days. From top to bottom rumen the share of solid digesta mass (SM), DM and NDF contents of squeezed digesta fluid (SRF) and concentration of SCFA decreased (P?P?相似文献   

Intake and digestion by lambs of dwarf elephant grass (Pennisetum purpureum Schum. cv. Mott) hay or hay supplemented with urea and different levels of cracked corn grain

This study was carried out to evaluate intake, digestibility, ruminal fermentation, nitrogen (N) retention and ruminal microbial protein synthesis in lambs fed dwarf elephant grass (Pennisetum purpureum Schum. cv. Mott) hay or hay supplemented with urea and 0, 5, 10 or 15 g/kg of live weight (LW) of cracked corn grain. Ten lambs (mean LW of 28 ± 0.9 kg), housed in metabolic cages, were used in a double 5 × 5 Latin Square experiment. Except fibre intake and digestibility, which was higher, the intake and digestibility of the others feed components, as well as ruminal microbial protein synthesis and N retention were lower in non-supplemented lambs. Corn supplementation increased total dry matter (DM) (P<0.05), organic matter (OM), non-structural carbohydrate (NSC) and energy intake (P<0.01) but decreased total neutral detergent fibre (aNDFom) (P<0.01) intake, as well as OM and aNDFom intake from the hay (P<0.01). Apparent DM, OM and energy digestibility, as well as OM true digestibility (OMTD) increased (P<0.01), and aNDFom digestibility decreased linearly (P<0.01) as corn supplementation increased. Total N intake was not influenced but, apparent and true N digestibility, as well as urinary N excretion decreased (P<0.01), and ruminal microbial N entering the small intestine increased linearly (P<0.01) as corn supplementation increased. However, the efficiency of ruminal microbial protein synthesis was similar for all treatments. Mean ruminal pH values and ammonia N concentrations decreased linearly (P<0.01) with level of corn supplementation. Ammonia N and amino acid, as well as peptide concentrations in ruminal fluid were quadratically related (P<0.01) with the time after feeding. Corn supplementation had a linear additive effect on total dry matter and digestible energy intake, as well as on N retention, but a linear negative effect on hay intake and on fibre digestibility. However, decreased forage digestibility by animals was probably neither related to lower ruminal pH, which values were always higher than 7.0, nor related to ruminal sugar concentrations, which were similar for all treatments.     

Effects of isobutyrate supplementation in pre- and post-weaned dairy calves diet on growth performance,rumen development,blood metabolites and hormone secretion

Isobutyrate supplements could improve rumen development by increasing ruminal fermentation products, especially butyrate, and then promote the growth performance of calves. The objective of this study was to evaluate the effects of isobutyrate supplementation on growth performance, rumen development, blood metabolites and hormone secretion in pre- and post-weaned dairy calves. In total, 56 Chinese Holstein male calves with 30 days of age and 72.9±1.43 kg of BW, blocked by days of age and BW, were assigned to four groups in a randomized block design. The treatments were as follows: control, low-isobutyrate, moderate-isobutyrate and high-isobutyrate with 0, 0.03, 0.06 and 0.09 g isobutyrate/kg BW per calf per day, respectively. Supplemental isobutyrate was hand-mixed into milk of pre-weaned calves and the concentrate portion of post-weaned calves. The study consisted of 10 days of an adaptation period and a 50-day sampling period. Calves were weaned at 60 days of age. Seven calves were chosen from each treatment at random and slaughtered at 45 and 90 days of age. BW, dry matter (DM) intake and stomach weight were measured, samples of ruminal tissues and blood were determined. For pre- and post-weaned calves, DM intake and average daily gain increased linearly (P<0.05), but feed conversion ratio decreased linearly (P<0.05) with increasing isobutyrate supplementation. Total stomach weight and the ratio of rumen weight to total stomach weight tended to increase (P=0.073) for pre-weaned calves and increased linearly (P=0.021) for post-weaned calves, whereas the ratio of abomasum weight to total stomach weight was not affected for pre-weaned calves and decreased linearly (P<0.05) for post-weaned calves with increasing isobutyrate supplementation. Both length and width of rumen papillae tended to increase linearly for pre-weaned calves, but increased linearly (P<0.05) for post-weaned calves with increasing isobutyrate supplementation. The relative expression of messenger RNA for growth hormone (GH) receptor and 3-hydroxy-3-methylglutaryl-CoA synthase 1 in rumen mucosa increased linearly (P<0.05) for pre- and post-weaned calves with increasing isobutyrate supplementation. Blood concentrations of glucose, acetoacetate, β-hydroxybutyrate, GH and IGF-1 increased linearly (P<0.05) for pre- and post-weaned calves, whereas blood concentration of insulin decreased linearly with increasing isobutyrate supplementation. The present results indicated that isobutyrate promoted growth of calves by improving rumen development and its ketogenesis in a dose-dependent manner.     

Effect of oat hay provision method on growth performance,rumen fermentation and blood metabolites of dairy calves during preweaning and postweaning periods

The comparison of the effects of all forage offering methods would be particularly useful information in modeling growth performance and rumen fermentation of dairy calves. Therefore, this study attempted to evaluate the effects of methods of oat hay provision on growth performance, rumen fermentation and biochemical blood indices of dairy calves during preweaning and postweaning periods. At birth, 40 female Polish Holstein-Friesian calves (3 days of age; 39.6 ± 0.39 kg BW) were randomly assigned to four treatment groups differing in the access to chopped oat hay: CON (control, starter without oat hay), OH (starter feed containing 10% DM basis oat hay), OH-FC (starter feed containing 10% DM basis oat hay and oat hay fed as free-choice provision in different buckets) and FC (starter feed and oat hay fed as free-choice provision in different buckets). The calves were weaned on day 56, and then the study continued until day 84. Intakes of starter feed and oat hay were recorded daily, whereas BW and hip height (HH) on day 3 and then every 14 days. Samples of blood were collected on the initiation of experiment and then every 14 days, and rumen contents on day 28, 56 and 84. No treatment effects were found for starter, starch, CP, total DM intake, average daily gain, feeding efficiency, change in HH, ruminal fluid pH, concentrations of ruminal propionate and NH₃-N, concentrations of urea nitrogen and non-esterified fatty acids in the blood. There were differences between treatments in terms of ruminal total volatile fatty acids and molar concentrations of acetate, butyrate and acetate to propionate ratio; highest in OH and OH-FC groups, especially during the postweaning period. On the other hand, lower concentrations of iso-valerate were found in OH and OH-FC groups on day 56 and 84. The concentrations of IGF-I throughout the experiment and β-hydroxybutyrate during the postweaning period in the blood were influenced by treatment, with the greatest values observed in OH and OH-FC calves. Results of this study indicate that starter feed containing chopped oat hay improves rumen fermentation parameters, which might allow successful transition from preruminant to mature ruminant state. Also, providing chopped oat hay with pelleted starter feed seems to be a better method than free-choice supplementation.     

Effect of harvesting period on the nutritive value of rice grass (Echinochloa sp.) hay given as sole diet to lambs

Data regarding the influence of maturity within the vegetative stage of tropical grasses on forage quality are limited and conflicting. The change in chemical composition of rice grass (Echinochloa sp.) hay harvested at 32, 46, 72 and 90 days of regrowth, and its effect on intake, digestibility, ruminal fermentation, rumen microbial protein synthesis (Experiment 1) and splanchnic oxygen uptake (Experiment 2) by lambs was evaluated. Except intake of indigestible neutral detergent fibre (NDF) which was similar for all treatments, intake of all hay components and the apparent digestibility of dry matter, organic matter (OM), NDF, N, as well as OM and N true digestibility, N retention and rumen microbial protein synthesis decreased linearly (P < 0.05) with increased regrowth age. Rumen fluid pH, ammonia N and peptide concentrations were similar for all treatments while sugars and amino acid concentrations decreased linearly with increased regrowth age of rice grass (P < 0.05). Passage rate of particles through reticulum-rumen (PRrr) was quadratically related (P < 0.05) to regrowth age. The highest PRrr and, consequently, the lowest retention time in the reticulum-rumen were obtained at 72 days of regrowth. There was a quadratic effect (P < 0.05) on net portal-drained viscera (PDV) flux of oxygen and heat production, while OM intake, portal blood flow and heat production as proportion of digestible energy (DE) intake were not affected by the increased regrowth age of rice grass. The highest means of oxygen uptake and heat production by PDV tissues were in 72 days treatment. In the whole splanchnic metabolism assay neither hay intake nor blood flow, oxygen uptake or heat production were affected by forage regrowth age. In conclusion, the nutritive value of rice grass hay decreased as regrowth age increased from 32 to 90 days due to decrease both OM intake and digestibility.     

Effects of protozoa on Methane production in rumen and hindgut of calves around time of weaning

Effects of the presence or absence of ciliate protozoa on methanogenesis in the rumen and hindgut were investigated in young calves during a 7-week period. Ten Holstein calves, aged 7 days, were divided in two groups (n = 5) and fed an increasing amount of a commercial milk replacer and small amounts of a calves starter. One group was inoculated with ciliate fauna on two occasions, week 5 and 6, while the second remained ciliate-free. The absence of protozoa in the rumen decreased rumen empty weight ( ? 23%, P < 0.01), and rumen pool size of N ( ? 36%, P < 0.01) and crude fat ( ? 37%, P < 0.05). Rumen bacteria of non-faunated calves contained a higher proportion of total amino acid-N per 16 g N ( + 3%, P < 0.01) and D-alanine-N per 16 g N ( + 13%, P < 0.05) compared to faunated calves. Further results contain a reference for a higher bacterial mass in the ciliate-free rumen with an increased number of bacteria adherent to rumen mucosa. The CH₄ production in the rumen increased exponentially with the increase in protozoa population size (R² = 0.68). In presence of 46 · 10⁴ protozoa per ml rumen fluid, the in vitro CH₄ production of rumen fluid per mol total VFA was about 34% higher in faunated than in non-faunated calves (P < 0.001). Hydrogen (2H) recovery of rumen fermentation was positively correlated (R² = 0.55) to the CH₄ production rate. Methanogens were attached on rumen mucosa. Methanogenesis, induced by rumen mucosa attached bacteria, was stimulated by ruminal protozoa. In the absence of protozoa in the rumen, the acetate - propionate ratio and butyrate proportion of VFA were reduced. In vivo in the absence of protozoa not only the whole animal CH₄ production ( ? 30%, P < 0.05) but also the digestibility of carbohydrates ( ? 4%, P < 0.05) was reduced. Thereby no difference was observed in the intake of ME per kg DM between the groups. In conclusion, the methanogenesis in the rumen, but not in hindgut, is associated with the development of the ruminal protozoa population. The level of methanogenesis (mol/mol VFA) in the hindgut amounts to 20% of the ruminal methanogenesis.     

Response of rumen microbiota,and metabolic profiles of rumen fluid,liver and serum of goats to high-grain diets

Feeding ruminants a high-grain (HG) diet is a widely used strategy to improve milk yield and cost efficiency. However, it may cause certain metabolic disorders. At present, information about the effects of HG diets on the systemic metabolic profile of goats and the correlation of such diets with rumen bacteria is limited. In the present study, goats were randomly divided into two groups: one was fed the hay diet (hay; n = 5), while the other was fed HG diets (HG; n = 5). On day 50, samples of rumen contents, peripheral blood serum and liver tissues were collected to determine the metabolic profiles in the rumen fluid, liver and serum and the microbial composition in rumen. The results revealed that HG diets reduced (P < 0.05) the community richness and diversity of rumen microbiota, with an increase in the Chao 1 and Shannon index and a decrease in the Simpson index. HG diets also altered the composition of rumen microbiota, with 30 genera affected (P < 0.05). Data on the metabolome showed that the metabolites in the rumen fluid, liver and serum were affected (variable importance projection > 1, P <0.05) by dietary treatment, with 47, 10 and 27 metabolites identified as differentially metabolites. Pathway analysis showed that the common metabolites in the shared key pathway (aminoacyl-transfer RNA biosynthesis) in the rumen fluid, liver and serum were glycine, lysine and valine. These findings suggested that HG diets changed the composition of the rumen microbiota and metabolites in the rumen fluid, liver and serum, mainly involved in amino acid metabolism. Our findings provide new insights into the understanding of diet-related systemic metabolism and the effects of HG diets on the overall health of goats.