Efficiency Of Microbial Production Research Articles

Effects of Different Essential Oil Blends and Fumaric Acid on In Vitro Fermentation, Greenhouse Gases, Nutrient Degradability, and Total and Molar Proportions of Volatile Fatty Acid Production in a Total Mixed Ration for Dairy Cattle

The present study evaluated the inclusion of fumaric acid and essential oil blends (EOBs) containing anise, cedarwood, clove, cumin, eucalyptus, garlic, ginger, lavender, lemongrass, nutmeg, oregano, and peppermint at different proportions on in vitro dry matter (DM) disappearance (DMD), fiber fraction disappearance, the efficiency of microbial production, and the total volatile fatty acids (VFAs). Ten treatments without (control treatment) or with different EOB/fumaric combinations were used in the study with eight replicates. The EOB inclusion level was 200 μL/g of feed (total mixed ration, (TMR)) while fumaric acid was administered at 3% of the TMR (DM basis). The highest DMD, in vitro true degradable DM, partitioning factor (PF24), and in vitro apparent degradable DM were recorded for the fumaric only treatment and the control. Neutral detergent fiber disappearance was reduced with the inclusion of EOB/fumaric combinations. The production of microbial mass and undegraded DM were higher (p < 0.001) for all EOBs and EOB and fumaric treatments. The inclusion of EOB and fumaric combinations reduced (p < 0.001) the total gas production, methane, and ammonia, with a higher PF24 value noted for EOB3 treatment. The inclusion of individual EOB1 containing garlic, lemongrass, cumin, lavender, and nutmeg in a ratio of 4:2:2:1:1 or combined with fumaric acid yielded the highest propionate concentration across all treatments. We concluded that EOBs decreased methane production and nutrient degradability with better results with the individual EOB1 or EOB1/fumaric combination, which showed a potential enhancement in energy production.

Effects of Essential Oil Blends on In Vitro Apparent and Truly Degradable Dry Matter, Efficiency of Microbial Production, Total Short-Chain Fatty Acids and Greenhouse Gas Emissions of Two Dairy Cow Diets.

Simple SummaryLivestock accounts for an estimated 80% of total agricultural greenhouse gas emissions, making abatement of greenhouse gas emissions from livestock a high-priority challenge facing animal nutritionists. Mitigating greenhouse gases in ruminants without reducing animal production is desirable both as a strategy to reduce global greenhouse gas emissions and as a way of improving dietary feed efficiency. The inclusion of feed additives in the diets of ruminants can reduce energy losses as methane, which typically reduces animal performance and contributes to greenhouse gas emissions. The present study evaluated the abatement potential of nine essential oil blends to mitigate greenhouse gas emissions. The inclusion of the blends resulted in a reduction in greenhouse gas emissions and in vitro apparent dry matter digestibility with higher values noted for the control treatment. A similar trend was noted for in vitro truly dry matter digestibility with higher values noted in the control treatment. The efficiency of microbial production was greater for the blends. The inclusion of the blends affected the total and molar proportion of volatile fatty acid concentrations. Overall, inclusion of the blends modified the rumen function resulting in improved efficiency of microbial production.The current study evaluated nine essential oil blends (EOBs) for their effects on ruminal in vitro dry matter digestibility (IVDMD), efficiency of microbial production, total short-chain fatty acid concentration (SCFA), total gas, and greenhouse gas (GHG) emissions using two dietary substrates (high forage and high concentrate). The study was arranged as a 2 × 2 × 9 + 1 factorial design to evaluate the effects of the nine EOBs on the two dietary substrates at two time points (6 and 24 h). The inclusion levels of the EOBs were 0 µL (control) and 100 µL with three laboratory replicates. Substrate × EOBs × time interactions were not significant (p > 0.05) for total gas and greenhouse gas emissions. The inclusion of EOBs in the diets resulted in a reduction (p < 0.001) in GHG emissions, except for EOB1 and EOB8 in the high concentrate diet at 6 h and for EOB8 in the high forage diet at 24 h of incubation. Diet type had no effect on apparent IVDMD (IVADMD) whereas the inclusion of EOBs reduced (p < 0.05) IVADMD with higher values noted for the control treatment. The efficiency of microbial production was greater (p < 0.001) for EOB treatments except for EOB1 inclusion in the high forage diet. The inclusion of EOBs affected (p < 0.001) the total and molar proportion of volatile fatty acid concentrations. Overall, the inclusion of the EOBs modified the rumen function resulting in improved efficiency of microbial production. Both the apparent and truly degraded DM was reduced in the EOB treatments. The inclusion of EOBs also resulted in reduced GHG emissions in both diets, except for EOB8 in the high forage diet which was slightly higher than the control treatment.

Effects of Yucca schidigera Based Feed Additive on In Vitro Dry Matter Digestibility, Efficiency of Microbial Production, and Greenhouse Gas Emissions of Four Dairy Diets

The present study evaluated the effects of a feed additive (synthesized from Yucca schidigera) on some fermentation variables. In the first of two experiments, seven concentrations of the feed additive were evaluated using the in vitro batch culture technique to determine the optimum dose to use in the second experiment. The substrates used were a total mixed ration (TMR) and alfalfa hay. The levels of inclusion were 0 (control), 0.5, 1, 2, 4, 6, and 8 g/head/d. After this initial evaluation, 2 g/head/d was selected for the second experiment. For the second study, four dietary substrates (two corn silages and two TMR; collected from different dairy farms in the Piedmont, North Carolina, area) were used. Incubation times were 3, 6, and 24 h and treatments were 0 (control) and 2 g/head/d of the feed additive. Inclusion of the feed additive did not affect (p &gt; 0.05) in vitro dry matter disappearance. Additionally, the feed additive had no effect (p &gt; 0.05) on short-chain fatty acid concentrations, microbial mass, and efficiency of microbial production. Methane production was reduced by 22.7% with feed additive inclusion. Similarly, lower (p = 0.013; 18%) carbon dioxide concentration was observed in the feed additive treatment. Ammonia and hydrogen sulfite concentrations were similar (p &gt; 0.05) for both treatments. Inclusion of the feed additive at 2 g/head/d decreased methane and carbon dioxide concentrations in most of the diets. The energy saved by reducing the amount of methane produced was not partitioned into valuable products such as short-chain fatty acids and microbial mass.

The use of live yeast to increase intake and performance of cattle receiving low-quality tropical forages

The objective was to evaluate the effects of a specific strain of live yeast (LY) on growth performance, fermentation parameters, feed efficiency, and bacterial communities in the rumen of growing cattle fed low-quality hay. In experiment (exp.) 1, 12 Droughtmaster bull calves (270 ± 7.6 kg initial body weight [BW]) were blocked by BW into two groups, allocated individually in pens, and fed ad libitum Rhodes grass hay (8.4% of crude protein [CP]) and 300 g/bull of supplement (52% CP) without (Control) or with LY (8 × 109 colony-forming unit [CFU]/d Saccharomyces cerevisiae CNCM I-1077; Lallemand Inc., Montreal, Canada) for 28 d, followed by 7 d in metabolism crates. Blood and rumen fluid were collected before feeding and 4 h after feeding. In exp. 2, for assessment of growth performance, 48 Charbray steers (329 ± 20.2 kg initial BW) were separated into two blocks by initial BW and randomly allocated into 12 pens. The steers were fed Rhodes grass hay (7.3% CP) and 220 g/steer of supplement (60% CP) without or with LY (8 × 109 CFU/d) for 42 d, after a 2-wk adaptation period. In exp. 1, fiber digestibility was calculated from total fecal collection, and, in exp 2, indigestible neutral detergent fiber (NDF) was used as a marker. Inclusion of LY increased (P = 0.03) NDF intake by 8.3% in exp. 1, without affecting total tract digestibility. No changes were observed in microbial yield or in the efficiency of microbial production. There was a Treatment × Time interaction (P < 0.01) for the molar proportion of short-chain fatty acids, with LY increasing propionate before feeding. Inclusion of LY decreased rumen ammonia 4 h after feeding (P = 0.03). The addition of LY reduced rumen bacterial diversity and the intraday variation in bacterial populations. Relative populations of Firmicutes and Verrucomicrobia varied over time (P < 0.05) only within the Control group. At the genus level, the relative abundance of an unclassified bacterial genus within the order Clostridiales, a group of cellulolytic bacteria, was reduced from 0 to 4 h after feeding in the Control group (P = 0.02) but not in the LY group (P = 1.00). During exp. 2, LY tended to increase average daily gain (ADG) (P = 0.08) and feed efficiency (P = 0.10), with no effect on NDF intake or digestibility. In conclusion, S. cerevisiae CNCM I-1077 reduced the intraday variation of rumen bacteria and increased the amount of NDF digested per day. These observations could be associated with the tendency of increased ADG and feed efficiency in growing cattle fed a low-quality forage.

Performance, digestibility, nitrogen balance and ingestive behaviour of goat kids fed diets supplemented with condensed tannins from

Context Tannins are phenolic compounds derived from secondary plant metabolism that at moderate levels can limit the excessive degradation of the protein in the rumen and provide greater amino acids availability in the small intestine. Aims Two experiments were performed to determine the best level of inclusion of condensed tannins (CT) from Acacia mearnsii extract in the diet of goat kids. An experiment was performed with 32 castrated crossbreed Boer goat kids, with a mean age of 4 months and mean bodyweight (BW) of 19.7 ± 2.05 kg, to measure nutrient intake and performance, and another experiment was developed with 20 Boer goat kids, at 5 months of age and 29.0 ± 2.45 kg BW, in which the digestibility, nitrogen (N) balance, microbial protein synthesis, ingestive behaviour and blood urea N were determined. In both experiments, a completely randomised design was used, including CT levels at 0, 16, 32 and 48 g/kg DM. Results DM; crude protein; ether extract; neutral detergent fibre (NDF); non-fibrous carbohydrates and total digestible nutrients intakes, ether extract digestibility; time spent on ruminating, idling or chewing; number of chews per bolus; eating and ruminating rate of DM and NDF; N intake and retained, blood urea N and loin eye area were not affected (P &gt; 0.05) by the addition of CT from A. mearnsii extract in the goat kid diets. However, the NDF g/kg BW and BW0.75 intakes and N faecal excretion showed a linear increase (P &lt; 0.05). There was a linear increase trend (P &lt; 0.1) in time spent eating, and a linear decrease on N urinary excretion by CT from A. mearnsii extract inclusion. The digestibility of DM, crude protein, NDF, non-fibrous carbohydrates and total digestible nutrients exhibited a linear decrease (P &lt; 0.05) by CT from A. mearnsii extract inclusion. There was a quadratic increase (P &lt; 0.05) in synthesis and microbial efficiency, final BW, average daily gain, total gain, gain:feed ratio, and hot and cold carcass weights and yields. Conclusion The inclusion of CT from A. mearnsii extract up to 17.7 g/kg DM is recommended, as it improves the synthesis and efficiency of microbial production, increasing the gain:feed ratio and performance of goat kids. Implications The use of condensed tannins from A. mearnsii does not affect the nutrient intakes on goat kids’ diet and also improves performance and carcass trait of these animals.

Can microbes compete with cows for sustainable protein production - A feasibility study on high quality protein.

An increasing population and their increased demand for high-protein diets will require dramatic changes in the food industry, as limited resources and environmental issues will make animal derived foods and proteins, gradually more unsustainable to produce. To explore alternatives to animal derived proteins, an economic model was built around the genome-scale metabolic network of E. coli to study the feasibility of recombinant protein production as a food source. Using a novel model, we predicted which microbial production strategies are optimal for economic return, by capturing the tradeoff between the market prices of substrates, product output and the efficiency of microbial production. A case study with the food protein, Bovine Alpha Lactalbumin was made to evaluate the upstream economic feasibilities. Simulations with different substrate profiles at maximum productivity were used to explore the feasibility of recombinant Bovine Alpha Lactalbumin production coupled with market prices of utilized materials. We found that recombinant protein production could be a feasible food source and an alternative to traditional sources.

Comparison of methane produced by straw fed sheep in open-circuit respiration with methane predicted by fermentation characteristics measured by an in vitro gas procedure

Reducing carbon conversion of ruminally degraded feed into methane increases feed efficiency and reduces emission of this potent greenhouse gas into the environment. Accurate, yet simple, predictions of methane production of ruminants on any feeding regime are important in the nutrition of ruminants, and in modeling methane produced by them. The current work investigated feed intake, digestibility and methane production by open-circuit respiration measurements in sheep fed 15 untreated, sodium hydroxide (NaOH) treated and anhydrous ammonia (NH 3) treated wheat, barley and oat straws. In vitro fermentation characteristics of straws were obtained from incubations using the Hohenheim gas production system that measured gas production, true substrate degradability, short-chain fatty acid production and efficiency of microbial production from the ratio of truly degraded substrate to gas volume. In the 15 straws, organic matter (OM) intake and in vivo OM digestibility ranged from 563 to 1201 g and from 0.464 to 0.643, respectively. Total daily methane production ranged from 13.0 to 34.4 l, whereas methane produced/kg OM matter apparently digested in vivo varied from 35.0 to 61.8 l. The OM intake was positively related to total methane production ( R 2 = 0.81, P<0.0001), and in vivo OM digestibility was also positively associated with methane production ( R 2 = 0.67, P<0.001), but negatively associated with methane production/kg digestible OM intake ( R 2 = 0.61, P<0.001). In the in vitro incubations of the 15 straws, the ratio of acetate to propionate ranged from 2.3 to 2.8 ( P<0.05) and efficiencies of microbial production ranged from 0.21 to 0.37 ( P<0.05) at half asymptotic gas production. Total daily methane production, calculated from in vitro fermentation characteristics (i.e., true degradability, SCFA ratio and efficiency of microbial production) and OM intake, compared well with methane measured in the open-circuit respiration chamber ( y = 2.5 + 0.86 x, R 2 = 0.89, P<0.0001, Sy. x = 2.3). Methane production from forage fed ruminants can be predicted accurately by simple in vitro incubations combining true substrate degradability and gas volume measurements, if feed intake is known.

Methodological considerations in using gas production techniques for estimating ruminal microbial efficiencies for silage-based diets

The relationship between in vivo and in vitro estimates of efficiency of microbial production (EMP) was tested using four silage-based diets. In vivo estimates were based on renal allantoin excretion in steers and in vitro estimates were based on a combination of gas volume and true substrate degradability (TSD OM) measures conducted at substrate-specific times. After an initial test to evaluate 96 h gas production profiles of diets incubated in both N-low and N-rich media, the time to half maximal gas production ( t 1/2) was calculated and a second incubation conducted in both media with fermentation stopped at t 1/2 for each substrate. True substrate degradability was measured from incubation residues and combined with gas volumes to estimate EMP. Additionally, microbial N (MN) production estimates were made using two equations from information on dietary N, N content of residues and NH 3–N content of media before and after incubation. In vitro estimates of EMP were related to in vivo EMP in both N-low ( R 2 = 0.94, P=0.03) and N-rich ( R 2 = 0.91, P=0.04) incubation media. No relationships occurred between in vitro efficiency of microbial N production and in vivo EMP when microbial N production was calculated from direct N determinations using N content of the apparently degraded residue after centrifugation and NDFN of the incubation residue. When in vitro microbial N production was estimated indirectly by accounting for dietary N, changes in NH 3–N concentrations in the incubation medium and NDFN in the incubation residue, efficiency of microbial N production relative to 100 mg TSD OM tended ( R 2 = 0.83, P=0.09) to be positively related to in vivo EMP. Silage fermentation acids appeared to interfere with relationships between gas production and in vitro substrate degradability measures because they were removed from the incubation residue without having contributed to fermentation. Therefore, silage acids should be accounted for when using combined in vitro gas production and true substrate degradability estimates to evaluate EMP of silage-based diets. N supplementation of incubation medium can influence substrate use for microbial growth, and attempts should be made to simulate in vivo N availability. It may be possible to rank silage-based diets for microbial efficiency using combined gas volume and true substrate degradability measures conducted at substrate-specific times ( t 1/2).

Rumen digesta kinetics in cold exposed prolific sheep: impact on protein evaluation

In vivo measurements of the changes over time in rumen degraded and undegraded protein fractions were used to study effects of midwinter shearing of prolific ewes on effective rumen degradability of dietary protein (EPD). Values were compared to EPD estimated with the standard method of in situ feed characteristics and an assumed rumen passage rate. The effect of the experimental treatments (unshorn and shorn) was investigated in ewes during three years ( n=11). Rumens of the sheep were emptied and sampled 1, 2, 4, 8 and 12 h after feeding to monitor rumen contents of dry matter (DM), crude protein-free organic matter (OM-CP) and nitrogen (N). The degraded and undegraded fractions of DM, OM-CP and N in rumen contents were measured by in situ rumen incubation of rumen content samples. Protein evaluation based on EPD estimated from changes in rumen digesta volume with time had more variation and 10% more digestible protein in the small intestine (DVE) than the commonly used EPD. Midwinter shearing of crossbred ewes increased the extent of degradation of DM and OM-CP in the rumen. The extent of degradation of protein tended to be higher in shorn ewes. These differences did not result in different DVE yields with an assumption of an unchanged efficiency of microbial protein growth during cold exposure. While the commonly used EPD is more suitable for routine techniques than EPD based on changes in rumen digesta volume over time, the commonly used EPD may result in an underestimation of the DVE value of feeds for prolific ewes. Protein evaluation should take account of differences in efficiency of microbial production between unshorn and shorn ewes to avoid underestimation of the DVE value of feeds.

Predicting ruminal microbial efficiencies of dairy rations by in vitro techniques

The efficiency of microbial production (EMP) of nine mixed diets consisting of approximately even parts of roughage and concentrates was investigated in vivo and in vitro. EMP in vivo was estimated based on ruminal 15N infusions of dairy cows and varied from 27.8 to 34.6 g of nitrogen (N) per kg truly fermented OM (mean=31.9 g). EMP in vitro was estimated by partitioning factor (PF ratio of mg of OM truly degraded to ml gas produced thereby), by two microbial N balances and by purine base (PB: adenine and guanine) analysis. Both microbial N balances were based on the determination of undegraded feed N by neutral detergent (ND) solution treatment and N analysis. Changes in the NH 4 concentrations in the incubation medium were taken into account in one of the microbial N balances. All in vitro incubations were conducted in N-low (−NH 4) and N-rich (+NH 4) medium. In vitro digestibility measurements were consistently higher ( P<0.0001) in N-rich medium but the effect of N-level on in vitro microbial efficiency varied in dependence of how microbial production was analyzed. Of the estimates of EMP in vitro only PF values were significantly related to EMP in vivo, the relationship being slightly closer for the −NH 4 ( r=0.77, P=0.016) than for the +NH 4 ( r=0.74, P=0.022) medium. PB per unit ATP (μmol/mmol) tended to be inversely related to EMP in vivo in both −NH 4 ( r=−0.52, P=0.148) and +NH 4 ( r=−0.32, P=0.403) medium. The amount of substrate truly degraded in vitro as determined by ND-solution treatment was in good agreement with the sum of the fermentation products recovered suggesting that this treatment can also be used for the estimation of in vitro true degradability of mixed diets.