Effect of the rumen ciliates Entodinium caudatum, Epidinium ecaudatum and Eudiplodinium maggii, and combinations thereof, on ruminal fermentation and total tract digestion in sheep

The quantitative importance of individual ciliate species and their interaction in the rumen is still unclear. The present study was performed to test whether there are species differences in the influence on ruminal fermentation in vivo and if combinations of ciliates act additive in that respect. Six adult wethers fed a hay-concentrate diet were defaunated, then refaunated either with Entodinium caudatum (EC), Epidinium ecaudatum (EE) or Eudiplodinium maggii (EM) alone, then progressively with all possible species combinations. Feed, faeces, urine, ruminal fluid and gas were sampled for eight days always after at least 21 days of adaptation. With a linear mixed model, accounting for the 2 x 2 x 2 full factorial study design, mean marginal effect sizes, i.e., the magnitude of change in variables as caused by the presence of each ciliate species or of combinations of them, were estimated. The apparent digestibility of organic matter and neutral detergent fibre remained unaffected. The apparent N digestibility increased by 0.054 with EM (0.716 with defaunation). Ruminal ammonia increased by 1.6, 4.0 and 8.7 mmol/l in the presence of EM, EC and EE, respectively, compared to defaunation (6.9 mmol/l). In the EM + EE combination, ruminal ammonia was lower than would have been expected from an additive effect. With EE, total short-chain fatty acids increased by 23 mmol/l (100 mmol/l with defaunation), but not when EE was combined with EM. The acetate-to-propionate ratio decreased by 0.73 units in the presence of EE (4.0 with defaunation), but only when EE was the sole ciliate species in the rumen. In the presence of any ciliate species, the 16S rDNA copies of total Bacteria and major fibrolytic species decreased to 0.52- and 0.22-fold values, respectively of that found without protozoa. Total Archaea were unaffected; however, Methanobacteriales copies increased 1.44-fold with EC. The CH4-to-CO2 ratio of ruminal gas decreased by 0.036 with EM and 0.051 with EE (0.454 with defaunation). In conclusion, individual ciliates affected ruminal fermentation differently and, when different species were combined, sometimes in a non-additive manner. From the ciliates investigated, EE affected ruminal fermentation most and might play a dominant role in mixed ciliate populations.     

Suitability of different media for in vitro cultivation of the ruminal protozoa species Entodinium caudatum, Eudiplodinium maggii, and Epidinium ecaudatum

Three protozoal cultivation media were tested to determine the medium which best facilitated growth and viability of key B-type ciliates isolated from the sheep rumen. Entodinium caudatum and Eudiplodinium maggii were grown anaerobically in 50-ml flasks for 32 days in Caudatum-type (C), Kisidayova (K) or Dehority (M) medium. On day 32, in media K and M, E. caudatum cell counts were high with 5.6 × 10³ and 7.8 × 10³ mL⁻¹, respectively, and the proportion of dead cells was low with 0.6 and 1.4%, respectively. E. maggii concentrations when grown in medium M and C were 2.7 × 10³ and 2.4 × 10³ mL⁻¹, respectively, with 3.9 and 14.1% dead cells. Medium M, which favoured growth of both protozoa species, was tested again and Epidinium ecaudatum was included. Protozoa were grown for a 4-month period and samples were taken in the last two months on days 1, 7, 35 and 57. Average cell concentrations were 10.0, 0.8 and 0.5 × 10³ mL⁻¹ for E. caudatum, E. maggii, and E. ecaudatum, respectively. In conclusion, medium M would appear to be the best choice for cultivating these three species in one medium.     

The ability of rumen ciliates, Eudiplodinium maggii, Diploplastron affine, and Entodinium caudatum, to use the murein saccharides

Murein polysaccharides may contribute to a considerable part of the dry matter of bacterial cells. Their utilization by protozoa inhabiting the rumen is, however, poorly recognized. The objective of this study was to examine the ability of three species of ciliates, i.e., Eudiplodinium maggii, Diploplastron affine, and Entodinium caudatum of digest, and ferment these saccharides. The cultivation experiments showed that the enrichment of growth medium with bacterial cell wall β-glycans increased the ciliate number (p?<?0.05). A statistically significant increase (p?<?0.01) was followed by a continuous decrease (p?<?0.01) in the percentage of individuals containing β-glycans particles after 4- and 24-h incubation of ciliates with this substrate, respectively. The enzymatic experiments confirmed the ability of the examined protozoa to digest murein. E. caudatum exhibited the highest activity (8.2 unit (U)/mg protein per min), and E. maggii, the lowest (3.0 U/mg protein per min). The production rates of volatile fatty acids by starved and fed ciliate species were 0.7 and 1.6 (E. caudatum)?pmol/ciliate cell per h, 30.5 and 42.5 (E. maggii)?pmol/ciliate cell per h, and 8.3 and 19.2 (D. affine)?pmol/ciliate cell per h (p?<?0.05).     

Effect of different levels of concentrate on ruminal microorganisms and rumen fermentation in Nellore steers

The aim of this study was to investigate the effect of different dietary levels of concentrate on feed intake, digestibility, ruminal fermentation and microbial population in steers. Eight Nellore steers fitted with ruminal cannulas were used in a double 4 × 4 Latin square design experiment. The dietary treatments consist of four different proportions of concentrate to roughage: 30:70, 40:60, 60:40 and 80:20% in the dry matter, resulting in Diets 30, 40, 60 and 80, respectively. The roughage was corn silage, and the concentrate was composed of corn, soybean meal and urea. Apparent digestibility of organic matter and crude protein showed a linear association with concentrate proportion (p = 0.01), but the increased concentrate levels did not affect the digestibility of fibre. The lowest ruminal pH-values were observed in animals fed with Diet 80, remaining below pH 6.0 from 6 h after feeding, while in the other diets, the ruminal pH was below 6.0 not before 12 h after feeding. After feeding Diet 80, the ammonia concentration in the rumen was significantly the highest. Higher dietary concentrate levels resulted in a linear increase of propionic acid concentrations, a linear reduction of the ratio acetic acid to propionic acid (p < 0.01) and a linear increased synthesis of microbial nitrogen (p < 0.001). The predicted production of methane was lower in diets with greater amounts of concentrate (p = 0.032). The population of methanogens, R. flavefaciens and R. albus decreased with higher concentrate levels, while the population of S. ruminantium increased (p < 0.05). The results indicate that greater amounts of concentrate do not decrease ruminal pH-values as much as expected and inhibit some cellulolytic bacteria without impairing the dry matter intake and fibre digestibility in Nellore steers.     

Effect of pH on viability of Entodinium caudatum, Entodinium exiguum, Epidinium caudatum, and Ophryoscolex purkynjei in vitro

Cultures of Entodinium caudatum, Entodinium exiguum, Epidinium caudatum, and Ophryoscolex purkynjei were grown and transferred in poorly buffered media prepared using different concentrations of sodium bicarbonate and a nitrogen gas phase. By transferring every 12 or 24 h, culture pH was gradually decreased until the protozoa disappeared. The cultures were transferred by placing half of the culture into an equal volume of fresh medium, resulting in pH fluctuations similar to those in the rumen, resulting from fermentation, eating, and saliva production. All four species appeared to maintain their concentrations around pH 5.8, but numbers decreased as pH values fell below 5.6. The four species were similar in that they all survived above pH 5.3. These results differ from previous reports in which Entodinium species appeared to be more tolerant to low pH than all other species of rumen ciliates. No adaptation to low pH was observed in Epidinium caudatum cultures after recovery from pH 5.4 medium containing only one or two viable cells.     

The effect of rumen ciliates on chitinolytic activity,chitin content and the number of fungal zoospores in the rumen fluid of sheep

The objective of this study was to investigate the effect of selected protozoa on the degradation and concentration of chitin and the numbers of fungal zoospores in the rumen fluid of sheep. Three adult ewes were fed a hay-concentrate diet, defaunated, then monofaunated with Entodinium caudatum or Diploplastron affine alone and refaunated with natural rumen fauna. The average density of the protozoa population varied from 6.1 · 10⁴ (D. affine) to 42.2 · 10⁴ cells/ml rumen fluid (natural rumen fauna). The inoculation of protozoa in the rumen of defaunated sheep increased the total activity of chitinolytic enzymes from 2.9 to 3.6 μmol N-acetylglucosamine/g dry matter (DM) of rumen fluid per min, the chitin concentration from 6.3 to 7.2 mg/g DM of rumen fluid and the number of fungal zoospores from 8.1 to 10.9 · 10⁵ cells/ml rumen fluid. All examined indices showed diurnal variations. Ciliate population density was highest immediately prior to feeding and lowest at 4 h thereafter. The opposite effects were observed for the numbers of fungal zoospores, the chitin concentration and chitinolytic activity. Furthermore, it was found that chitin from zoospores may account for up to 95% of total microbial chitin in the rumen fluid of sheep. In summary, the examined ciliate species showed the ability of chitin degradation as well as a positive influence on the development of the ruminal fungal population.     

Effects of dietary crude protein and tannic acid on rumen fermentation,rumen microbiota and nutrient digestion in beef cattle

The objectives of the trial were to study the effects of dietary crude protein (CP) and tannic acid (TA) on rumen fermentation, microbiota and nutrient digestion in beef cattle. Eight growing beef cattle (live weight 350 ± 25 kg) were allocated in a 2 × 2 crossover design using two levels of dietary CP [111 g/kg dry matter (DM) and 136 g/kg DM] and two levels of TA (0 and 16.9 g/kg DM) as experimental treatments. Each experimental period lasted 19 d, consisting of 14-d adaptation and 5-d sampling. The impacts of dietary CP and TA on ruminal microbiota were analysed using high-throughput sequencing of 16S rRNA gene. Results indicated that no interactions between dietary CP and TA were found on rumen fermentation and nutrient digestibility. Increasing dietary CP level from 111 to 136 g/kg DM increased the ruminal concentrations of ammonia nitrogen (NH₃-N) (p < 0.01) and improved the CP digestibility (p < 0.001). Adding TA at 16.9 g/kg DM inhibited rumen fermentation and decreased the digestibility of dietary CP (p < 0.001), DM (p < 0.05) and organic matter (p < 0.01). Increasing the dietary CP level or adding TA did not affect the relative abundances of the major bacteria Firmicutes and Proteobacteria at the phylum level and Prevotella_1 and Christensenellaceae_R-7_group at the genus level, even though adding TA increased the Shannon index of the ruminal bacterial community. TA was partly hydrolysed to pyrogallol, gallic acid and resorcinol in rumen fluid and the inhibitory effects of TA on rumen fermentation and nutrient digestibility could have been resulted from the TA metabolites including pyrogallol, gallic acid and resorcinol as well as the protein-binding effect.     

Xylanases and carboxymethylcellulases of the rumen protozoa Polyplastron multivesiculatum, Eudiplodinium maggii and Entodinium sp

Endoglucanase and xylanase activities of three rumen protozoa, Polyplastron multivesiculatum, Eudiplodinium maggii, and Entodinium sp. were compared qualitatively by zymograms and quantitatively by measuring specific activities against different polysaccharides. A set of carboxymethylcellulases and xylanases was produced by the large ciliates whereas no band of activity was observed for Entodinium sp. in zymograms. Specific activity of endoglucanases from P. multivesiculatum (1.3 micromol mg prot(-1) min(-1)) was twice that of E. maggii, whereas xylanase specific activity (4.5 micromol mg prot(-1) min(-1)) was only half. Very weak activities were observed for Entodinium sp. A new xylanase gene, xyn11D, from P. multivesiculatum was reported and its gene product compared to 33 other family 11 xylanases. Phylogenetic analysis showed that xylanase sequences from rumen protozoa are closely related to those of bacteria.     

Effect of complete feed blocks or grazing and supplementation of lambs on performance, nutrient utilisation, rumen fermentation and rumen microbial enzymes

A study to compare two feeding systems, stall feeding (SF) and grazing plus supplementation (GR) was carried out, based on intake, performance and rumen fermentation characteristics of lambs. While SF animals received ad libitum complete feed blocks (CFB), GR animals were allowed grazing for 8 h on a pasture and supplemented with concentrate mixture at 250 g per head per day. Intake in grazing animals was determined using chromium III oxide as internal marker. Intake of dry matter (DM), crude protein (CP) and organic matter (OM) were higher ( P < 0.01) in SF than in GR animals. Similarly, digestibility of OM, CP and energy were higher ( P < 0.01) in SF animals. Average daily gain in SF animals (101 g) was significantly ( P < 0.01) higher than in GR animals (78 g) but total wool yield was similar for the two groups (856 g, SF; 782 g, GR). The pH of the rumen content, concentration of total volatile fatty acids and total activities of carboxymethyl cellulase, xylanase and esterase in the rumen liquor were similar. The concentrations (mg/dl) of total nitrogen (125, SF; 63, GR) and NH₃-nitrogen (42, SF; 31, GR) were higher in SF animals than that of GR animals. A significantly higher activity ( P < 0.05) of microcrystalline cellulase (24.5 v. 7.7 units) and lower activity ( P < 0.05) of protease (309 v. 525 units), was observed in the rumen of SF animals than in GR animals. SF animals could therefore harness more energy through degradation of plant cell walls thus reducing breakdown of plant proteins as gluconeogenic source. The SF system of feeding where CFB was offered to sheep appeared superior to GR in terms of intake, nutrient utilisation and animal performance. Therefore the SF feeding system where CFB are offered to animals can be advocated as an alternative to grazing and supplementation feeding strategy for sheep production, especially where the pastures are highly eroded and need resting for regeneration or curing. The CFB feeding can also be adopted under adverse conditions like drought and famine, a common phenomenon in arid and semiarid conditions.     

Effects of dietary cellulase and xylanase addition on digestion,rumen fermentation and methane emission in growing goats

The objective of this study was to evaluate the effectiveness of supplementation of cellulase and xylanase to diets of growing goats to improve nutrient digestibility, utilisation of energy and mitigation of enteric methane emissions. The experiment was conducted in a 5 × 5 Latin square design using five goats with permanent rumen fistulae and five treatments consisted of two levels of cellulase crossed over with two levels of xylanase plus unsupplemented Control. The cellulase (243 U/g) derived from Neocallimastix patriciarum was added at 0.8 and 1.6 g/kg dry matter intake (DMI) and the xylanase (31,457 U/ml) derived from Aspergillus oryzae was fed at 1.4 and 2.2 ml/kg DMI. There were no differences in apparent digestibility of organic matter, neutral detergent fibre, acid detergent fibre and rumen fermentation parameters (i.e. ammonia-nitrogen [N], volatile fatty acids) among all treatments. Dietary cellulase and xylanase addition did not influence energy and N utilisation. But compared to xylanase addition at the higher dose, at the low xylanase dose the retained N, the availability of retained N and digested N were increased (p < 0.01). Moreover, enzyme addition did not affect the enteric methane emission and community diversity of ruminal methanogens. The present results indicated that previous in vitro findings were not confirmed in ruminant trials.     

Parameters of fermentation and rumen microbiota of Nellore steers fed with different proportions of concentrate in fresh sugarcane containing diets

The objective of this study was to evaluate the effect of a fresh sugarcane-based diet and different roughage-to-concentrate ratios (70:30, 60:40, 40:60 and 20:80) on the rumen microbiota associated with rumen fermentation parameters and the intake and apparent digestibility of nutrients in Nellore steers. Eight rumen-cannulated Nellore steers (331 ± 8 kg BW) were distributed in a double 4 × 4 Latin square design balanced for the control of the residual effect. The ruminal pH decreased (p < 0.01) and the concentrations of N–NH₃, isovaleric and valeric acids increased linearly (p < 0.05) with an increase dietary concentrate level. Furthermore, an increased concentrate proportion reduced the population of Fibrobacter succinogenes and Ruminococus flavefaciens (p < 0.01) and increased the population of Selenomonas ruminantium and Megasphaera elsdenii (p < 0.01). The protozoa count revealed a predominance of the genus Entodinium. The synthesis of microbial N [g/d] and the efficiency of microbial synthesis [g of microbial N/kg of organic matter apparently digested in the rumen] increased as the proportion of concentrate was increased (p < 0.05). Therefore, it can be concluded that an increasing proportion of concentrate in sugarcane-containing diets enhances the synthesis of microbial protein and does not alter the fibre digestibility, although the population of fibre fermenting bacteria was reduced.     

Effects of isobutyrate on rumen fermentation,urinary excretion of purine derivatives and digestibility in steers

The objective of this study was to evaluate the effects of isobutyrate supplementations on rumen fermentation, urinary excretion of purine derivatives and feed digestibility in steers. Eight ruminally cannulated Simmental steers were used in a replicated 4 × 4 Latin square experiment. On DM basis, diet consisted of 60% corn stover and 40% concentrate. Dry matter intake (averaged 9 kg/d) was restricted to 90% of ad libitum intake. The four treatment groups received a daily dose of 0 (control), 8.4, 16.8 or 25.2 g isobutyrate per steer. With increasing isobutyrate supplementation total VFA concentration (range 64.2–74.0 mM) was significantly enhanced. The ratio of acetate to propionate (range 2.72–4.25) was also significantly increased due to the increase in actate production and decrease in propionate production. With increasing isobutyrate supplementation the ruminal degradation of NDF from corn stover was improved but the CP degradability of soybean meal was decreased. Furthermore, the isobutyrate supplementation caused a significantly increased urinary excretion of purine derivatives. Similarly, digestibilities of OM, NDF and CP in the total tract were significantly increased. The present results indicate that dietary supplementation with isobutyrate improved rumen fermentation and feed digestion in beef cattle in a dose-dependent manner. According to the conditions of this experiment, the optimum daily dose of isobutyrate was about 16.8 g/animal.     

Effects of Bacillus subtilis natto on milk production,rumen fermentation and ruminal microbiome of dairy cows

Two experiments were conducted to evaluate the effects of Bacillus subtilis natto, which was initially isolated from fermented soybeans on milk production, rumen fermentation and ruminal microbiome in dairy cows. In Experiment 1, 36 early lactation Chinese Holstein dairy cows (56 ± 23 days in milk) were randomly assigned to three groups: Control, cows were fed total mixed ration (TMR); BSNLOW, TMR plus 0.5 × 10¹¹ colony-forming units (cfu) of B. subtilis natto/cow per day; and BSNHIGH, TMR plus 1.0 × 10¹¹ cfu of B. subtilis natto/cow per day. During the 70-day treatment period, daily milk production and daily milk composition were determined in individual cows. The results showed that supplementing dairy cows with 0.5 × 10¹¹ and 1.0 × 10¹¹ cfu of B. subtilis natto linearly increased (P < 0.01) milk production (25.2 and 26.4 kg/day v. 23.0 kg/day), 4% fat-corrected milk (27.3 and 28.1 kg/day v. 24.2 kg/day), energy-corrected milk (27.3 and 28.2 kg/day v. 24.2 kg/day), as well as milk fat (1.01 and 1.03 kg/day v. 0.88 kg/day), protein (0.77 and 0.82 kg/day v. 0.69 kg/day) and lactose yield (1.16 and 1.22 kg/day v. 1.06 kg/day) but decreased milk somatic cell counts (SCC) by 3.4% to 5.5% (P < 0.01) in BSNLOW and BSNHIGH treatments compared with Control. In Experiment 2, four rumen-cannulated dairy cows were fed the basal diet from 1 to 7 days (pre-trial period) and rumen samples were collected on days 6 and 7; the same cows then were fed 1.0 × 10¹¹ cfu/day B. subtilis natto from days 8 to 21 (trial period) and rumen samples were collected on days 20 and 21. B. subtilis natto was discontinued from days 22 to 28 (post-trial period) and rumen samples were collected on days 27 and 28. Compared with the pre- and post-periods, ruminal pH decreased by 2.7% to 3.0% during the trial period (P < 0.01), whereas ammonia nitrogen (NH₃-N), total volatile fatty acids and molar proportion of propionate (P < 0.01) and valerate (P < 0.05) increased. Molar proportion of acetate decreased and the acetate to propionate ratio was lower (P < 0.01) during the trial period. However, no differences for 24-h in sacco dry matter digestibility were detected among different periods (treatments) though NDF digestibility was reduced in the trial and post-trial periods (P < 0.01). Compared with pre-trial period, total ruminal bacteria, proteolytic and amylolytic bacteria in rumen enumerated by culture methods increased by 15.0%, 16.2% and 11.7%, respectively (P < 0.01) but protozoa decreased to 5.35 log₁₀ cfu/ml (P < 0.01) during the trial period. These results demonstrate that B. subtilis natto improves milk production and milk components yield, decreases SCC and promotes the growth of total ruminal bacteria, proteolytic and amylolytic bacteria, which indicate that B. subtilis natto has potential to be applied as a probiotic for dairy cows.     

Effects of malic acid on rumen fermentation, urinary excretion of purine derivatives and feed digestibility in steers

The objective of this study was to evaluate the effects of malic acid (MA) supplementation on rumen fermentation, urinary excretion of purine derivatives (PDs) and whole gastro-intestinal tract feed digestibility in steers. Eight ruminally cannulated Simmental steers (465 ± 13 kg) were used in a replicated 4 × 4 Latin square design. The treatments were: control (without MA), LMA (MA-low), MMA (MA-medium) and HMA (MA-high) with 0.0, 7.8, 15.6 and 23.4 g MA per kg dry matter (DM), respectively. Diets consisted of corn stover and concentrate (60/40, DM basis). DM intake was approximately 9 kg per day, which was 90% of ad libitum intake including 5.4 kg corn stover and 3.6 kg concentrate. Ruminal pH (range of 6.91 to 6.56), ratio of acetate to propionate (range of 3.88 to 3.25), ammonia N (range of 9.03 to 6.42 mg/100 ml) and lactate (range of 91.25 to 76.31 mg/100 ml) decreased linearly as MA supplementation increased, whereas total volatile fatty acid (VFA) concentration (range of 55.68 to 61.49 mM) linearly (P < 0.05) increased with increase in MA supplementation. In situ ruminal neutral detergent fiber (aNDF) degradation of corn stover was improved but the crude protein (CP) degradability of concentrate mix was decreased with increasing the dose of MA. Urinary excretion of PDs was quadratically (P < 0.01) changed with altering MA supplementation (67.88, 72.74, 75.81 and 73.78 mmol/day for control, LMA, MMA and HMA, respectively). Similarly, digestibilities of DM, organic matter (OM), NDF and acid detergent fiber (ADF) in the total tract were also quadratically increased with increasing MA, and no differences in terms of CP and ether extract digestibility were observed. The results indicate that MA supplementation has the potential to improve rumen fermentation and feed digestion in beef cattle. The MA stimulates the digestive microorganisms or enzymes in a quadratic response. In the experimental conditions of this trial, the optimum MA dose was 15.6 g MA per kg DM.     

Effects of guanidinoacetic acid supplementation on growth performance,nutrient digestion,rumen fermentation and blood metabolites in Angus bulls

Guanidinoacetic acid (GAA) can improve the growth performance of bulls. This study investigated the influences of GAA addition on growth, nutrient digestion, ruminal fermentation and serum metabolites in bulls. Forty-eight Angus bulls were randomly allocated to experimental treatments, that is, control, low-GAA (LGAA), medium-GAA (MGAA) and high-GAA (HGAA), with GAA supplementation at 0, 0.3, 0.6 and 0.9 g/kg DM, respectively. Bulls were fed a basal diet containing 500 g/kg DM concentrate and 500 g/kg DM roughage. The experimental period was 104 days, with 14 days for adaptation and 90 days for data collection. Bulls in the MGAA and HGAA groups had higher DM intake and average daily gain than bulls in the LGAA and control groups. The feed conversion ratio was lowest in MGAA and highest in the control. Bulls receiving 0.9 g/kg DM GAA addition had higher digestibility of DM, organic matter, NDF and ADF than bulls in other groups. The digestibility of CP was higher for HGAA than for LGAA and control. The ruminal pH was lower for MGAA, and the total volatile fatty acid concentration was greater for MGAA and HGAA than for the control. The acetate proportion and acetate-to-propionate ratio were lower for MGAA than for LGAA and control. The propionate proportion was higher for MGAA than for control. Bulls receiving GAA addition showed decreased ruminal ammonia N. Bulls in MGAA and HGAA had higher cellobiase, pectinase and protease activities and Butyrivibrio fibrisolvens, Prevotella ruminicola and Ruminobacter amylophilus populations than bulls in LGAA and control. However, the total protozoan population was lower for MGAA and HGAA than for LGAA and control. The total bacterial and Ruminococcus flavefaciens populations increased with GAA addition. The blood level of creatine was higher for HGAA, and the activity of l-arginine glycine amidine transferase was lower for MGAA and HGAA, than for control. The blood activity of guanidine acetate N-methyltransferase and the level of folate decreased in the GAA addition groups. The results indicated that dietary addition of 0.6 or 0.9 g/kg DM GAA improved growth performance, nutrient digestion and ruminal fermentation in bulls.     

Effect of insulin on in vitro fermentation activity of microrganism community of rumen ciliate Entodinium caudatum culture

The influence of insulin (17.4 nmol l-1) on total gas and methane production, the concentration of total and individual fatty acids and dry matter degradability was investigated in the rumen ciliate culture of Entodinium caudatum. The experimental groups consisted of control group (without insulin) and two groups with insulin application--single shot and long-term application (over 30 days). Fermentation activity of each experimental group was observed on two subgroups: whole protozoan culture (protozoa plus bacteria) and bacterial fraction (bacteria without protozoa). Long-term application of insulin significantly increased methane production and DM degradability in the whole protozoan culture. Total VFA concentration was significantly increased by long-term as well as single-dose application of insulin (by 255% and 158%, respectively). The growth of the protozoa was not influenced by insulin treatments. It can be concluded that the fermentation activity of the community of the rumen ciliate Entodinium caudatum culture was marked stimulated by application of insulin.     

Effects of sodium selenite and coated sodium selenite on lactation performance,total tract nutrient digestion and rumen fermentation in Holstein dairy cows

Se can enhance lactation performance by improving nutrient utilization and antioxidant status. However, sodium selenite (SS) can be reduced to non-absorbable elemental Se in the rumen, thereby reducing the intestinal availability of Se. The study investigated the impacts of SS and coated SS (CSS) supplementation on lactation performance, nutrient digestibility, ruminal fermentation and microbiota in dairy cows. Sixty multiparous Holstein dairy cows were blocked by parity, daily milk yield and days in milk and randomly assigned to five treatments: control, SS addition (0.3 mg Se/kg DM as SS addition) or CSS addition (0.1, 0.2 and 0.3 mg Se/kg DM as CSS addition for low CSS (LCSS), medium CSS (MCSS) and high CSS (HCSS), respectively). Experiment period was 110 days with 20 days of adaptation and 90 days of sample collection. Dry matter intake was higher for MCSS and HCSS compared with control. Yields of milk, milk fat and milk protein and feed efficiency were higher for MCSS and HCSS than for control, SS and LCSS. Digestibility of DM and organic matter was highest for CSS addition, followed by SS addition and then control. Digestibility of CP was higher for MCSS and HCSS than for control, SS and LCSS. Higher digestibility of ether extract, NDF and ADF was observed for SS or CSS addition. Ruminal pH decreased with dietary Se addition. Acetate to propionate ratio and ammonia N were lower, and total volatile fatty acids (VFAs) concentration was greater for SS, MCSS and HCSS than control. Ruminal H ion concentration was highest for MCSS and HCSS and lowest for control. Activities of cellobiase, carboxymethyl-cellulase, xylanase and protease and copies of total bacteria, fungi, Ruminococcus flavefaciens, Fibrobacter succinogenes and Ruminococcus amylophilus increased with SS or CSS addition. Activity of α-amylase, copies of protozoa, Ruminococcus albus and Butyrivibrio fibrisolvens and serum glucose, total protein, albumin and glutathione peroxidase were higher for SS, MCSS and HCSS than for control and LCSS. Dietary SS or CSS supplementation elevated blood Se concentration and total antioxidant capacity activity. The data implied that milk yield was elevated due to the increase in total tract nutrient digestibility, total VFA concentration and microorganism population with 0.2 or 0.3 mg Se/kg DM from CSS supplementation in dairy cows. Compared with SS, HCSS addition was more efficient in promoting lactation performance of dairy cows.