An NAD<sup>+</sup>-dependent glutamate dehydrogenase cloned from the ruminal ciliate protozoan,<i>Entodinium caudatum</i>

Newbold, C. J.; McEwan, Neil R.; Calza, R. E.; Chareyron, Emilie N.; Duval, StÃ©phane M.; Eschenlauer, Sylvain C.P.; McIntosh, Freda M.; Nelson, Nancy L.; Travis, Anthony J.; Wallace, R. J.

doi:10.1016/j.femsle.2005.04.034

Cited by 18 publications

(23 citation statements)

References 33 publications

(43 reference statements)

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“…Thus, while much progress has been made in describing the role of protozoa in the rumen (Williams and Coleman, 1992), it has been difficult to establish conclusively that activity is due to protozoa as opposed to associated bacteria. Techniques to clone and express ciliate genes in phages have allowed genes from a range of rumen protozoa to be characterized (McEwan et al, 1999;Newbold et al, 2005;Belzecki et al, 2007). As a result, a wide range of fibrolytic enzymes have been identified suggesting a highly evolved fibrolytic capacity in the rumen ciliates (Devillard et al, 1999 and2003;Takenaka et al, 2004;Wereszka et al, 2004;Bera-Maillet et al, 2005).…”

Section: Protozoamentioning

confidence: 99%

Review: Ruminal microbiome and microbial metabolome: effects of diet and ruminant host

Newbold

Ramos-Morales

2020

Animal

128

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The rumen contains a great diversity of prokaryotic and eukaryotic microorganisms that allow the ruminant to utilize ligno-cellulose material and to convert non-protein nitrogen into microbial protein to obtain energy and amino acids. However, rumen fermentation also has potential deleterious consequences associated with the emissions of greenhouse gases, excessive nitrogen excreted in manure and may also adversely influence the nutritional value of ruminant products. While several strategies for optimizing the energy and nitrogen use by ruminants have been suggested, a better understanding of the key microorganisms involved and their activities is essential to manipulate rumen processes successfully. Diet is the most obvious factor influencing the rumen microbiome and fermentation. Among dietary interventions, the ban of antimicrobial growth promoters in animal production systems has led to an increasing interest in the use of plant extracts to manipulate the rumen. Plant extracts (e.g. saponins, polyphenol compounds, essential oils) have shown potential to decrease methane emissions and improve the efficiency of nitrogen utilization; however, there are limitations such as inconsistency, transient and adverse effects for their use as feed additives for ruminants. It has been proved that the host animal may also influence the rumen microbial population both as a heritable trait and through the effect of early-life nutrition on microbial population structure and function in adult ruminants. Recent developments have allowed phylogenetic information to be upscaled to metabolic information; however, research effort on cultivation of microorganisms for an in-depth study and characterization is needed. The introduction and integration of metagenomic, transcriptomic, proteomic and metabolomic techniques is offering the greatest potential of reaching a truly systems-level understanding of the rumen; studies have been focused on the prokaryotic population and a broader approach needs to be considered.

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Section: Protozoamentioning

confidence: 99%

Review: Ruminal microbiome and microbial metabolome: effects of diet and ruminant host

Newbold

Ramos-Morales

2020

Animal

128

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“…These results were attributed to decreased competitiveness by AA-using bacteria compared with protozoa, which can satisfy AA requirements by consuming bacteria (Dennis et al, 1983;Dehority, 2003). However, a low-affinity glutamate dehydrogenase was more recently cloned from Entodinium caudatum (Newbold et al, 2005), so direct effects of urea combined with M cannot be ruled out. Epidinium and members of the family Diplodiniinae are important degraders of hemicellulose (Béra-Maillet et al, 2005), so perhaps the greater proportion of hemicellulose in corn silage NDF than in alfalfa NDF promoted growth of these protozoa.…”

Section: Protozoal Countsmentioning

confidence: 99%

Interaction of molasses and monensin in alfalfa hay- or corn silage-based diets on rumen fermentation, total tract digestibility, and milk production by Holstein cows

Oelker

Reveneau

Firkins

2009

Journal of Dairy Science

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Sugar supplementation can stimulate rumen microbial growth and possibly fiber digestibility; however, excess ruminal carbohydrate availability relative to rumen-degradable protein (RDP) can promote energy spilling by microbes, decrease rumen pH, or depress fiber digestibility. Both RDP supply and rumen pH might be altered by forage source and monensin. Therefore, the objective of this study was to evaluate interactions of a sugar source (molasses) with monensin and 2 forage sources on rumen fermentation, total tract digestibility, and production and fatty acid composition of milk. Seven ruminally cannulated lactating Holstein cows were used in a 5 x 7 incomplete Latin square design with five 28-d periods. Four corn silage diets consisted of 1) control (C), 2) 2.6% molasses (M), 3) 2.6% molasses plus 0.45% urea (MU), or 4) 2.6% molasses plus 0.45% urea plus monensin sodium (Rumensin, at the intermediate dosage from the label, 16 g/909 kg of dry matter; MUR). Three chopped alfalfa hay diets consisted of 1) control (C), 2) 2.6% molasses (M), or 3) 2.6% molasses plus Rumensin (MR). Urea was added to corn silage diets to provide RDP comparable to alfalfa hay diets with no urea. Corn silage C and M diets were balanced to have 16.2% crude protein; and the remaining diets, 17.2% crude protein. Dry matter intake was not affected by treatment, but there was a trend for lower milk production in alfalfa hay diets compared with corn silage diets. Despite increased total volatile fatty acid and acetate concentrations in the rumen, total tract organic matter digestibility was lower for alfalfa hay-fed cows. Rumensin did not affect volatile fatty acid concentrations but decreased milk fat from 3.22 to 2.72% in corn silage diets but less in alfalfa hay diets. Medium-chain milk fatty acids (% of total fat) were lower for alfalfa hay compared with corn silage diets, and short-chain milk fatty acids tended to decrease when Rumensin was added. In whole rumen contents, concentrations of trans-10, cis-12 C(18:2) were increased when cows were fed corn silage diets. Rumensin had no effect on conjugated linoleic acid isomers in either milk or rumen contents but tended to increase the concentration of trans-10 C(18:1) in rumen samples. Molasses with urea increased ruminal NH(3)-N and milk urea N when cows were fed corn silage diets (6.8 vs. 11.3 and 7.6 vs. 12.0 mg/dL for M vs. MU, respectively). Based on ruminal fermentation characteristics and fatty acid isomers in milk, molasses did not appear to promote ruminal acidosis or milk fat depression. However, combinations of Rumensin with corn silage-based diets already containing molasses and with a relatively high nonfiber carbohydrate:forage neutral detergent fiber ratio influenced biohydrogenation characteristics that are indicators of increased risk for milk fat depression.

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“…In the calculation, we assumed that 90% of the enriched 15 N in the protozoa is of bacterial origin, recognizing the capability of protozoa for de novo synthesis of AA from ammonia (Williams and Harfoot, 1976;Williams and Coleman, 1997;Newbold et al, 2005). The calculation also assumes that 50% of the engulfed N is Figure 1.…”

Section: Calculationsmentioning

confidence: 99%

Rumen digestion kinetics, microbial yield, and omasal flows of nonmicrobial, bacterial, and protozoal amino acids in lactating dairy cattle fed fermentation by-products or urea as a soluble nitrogen source

Fessenden

Hackmann

Ross

et al. 2019

Journal of Dairy Science

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The objective of this study was to evaluate the effect of a fermentation by-product on rumen function, microbial yield, and composition and flows of nutrients from the rumen in high-producing lactating dairy cattle. Eight ruminally cannulated multiparous Holstein cows averaging (mean ± standard deviation) 60 ± 10 d in milk and 637 ± 38 kg of body weight were randomly assigned to 1 of 2 treatment sequences in a switchback design. Treatment diets contained (dry matter basis) 44% corn silage, 13% alfalfa silage, 12% ground corn, and 31% protein premix, containing either a control mix of urea and wheat middlings (CON) or a commercial fermentation by-product meal (Fermenten, Arm and Hammer Animal Nutrition, Princeton, NJ) at 3% diet inclusion rate (EXP). The trial consisted of three 28-d experimental periods, where each period consisted of 21 d of diet adaptation and 7 d of data and sample collection. A triple-marker technique and double-labeled 15 N 15 N-urea were used to were used to measure protozoal, bacterial, and nonmicrobial omasal flow of AA. Rumen pool sizes and omasal flows were used to determine digestion parameters, including fractional rates of carbohydrate digestion, microbial growth, and yield of microbial biomass per gram of degraded substrate. Fermentation by-product inclusion in EXP diets increased microbial N and amino acid N content in microbes relative to microbes from CON cows fed the urea control. Microbial AA profile did not differ between diets. Daily omasal flows of AA were increased in EXP cows as a result of decreased degradation of feed protein. The inclusion of the fermentation by-product increased nonmicrobial AA flow in cows fed EXP versus CON. Average protozoal contribution to microbial N flow was 16.8%, yet protozoa accounted for 21% of the microbial AA flow, with a range of 8 to 46% for individual AA. Cows in this study maintained an average rumen pool size of 320 g of microbial N, and bacterial and protozoal pools were estimated at 4 different theoretical levels of selective protozoa retention. Fractional growth rate of all microbes was estimated to be 0.069 h −1 , with a yield of 0.44 g of microbial biomass per gram of carbohydrate degraded. Results indicated that fermentation by-product can increase omasal flow of AA while maintaining adequate rumen N available for microbial growth and protein synthesis. Simulations from a developmental version of the Cornell Net Carbohydrate and Protein System indicated strong agreement between predicted and observed values, with some areas key for improvement in AA flow and bacterial versus protozoal N partitioning.

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An NAD⁺-dependent glutamate dehydrogenase cloned from the ruminal ciliate protozoan,Entodinium caudatum

Cited by 18 publications

References 33 publications

Review: Ruminal microbiome and microbial metabolome: effects of diet and ruminant host

Review: Ruminal microbiome and microbial metabolome: effects of diet and ruminant host

Interaction of molasses and monensin in alfalfa hay- or corn silage-based diets on rumen fermentation, total tract digestibility, and milk production by Holstein cows

Rumen digestion kinetics, microbial yield, and omasal flows of nonmicrobial, bacterial, and protozoal amino acids in lactating dairy cattle fed fermentation by-products or urea as a soluble nitrogen source

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An NAD+-dependent glutamate dehydrogenase cloned from the ruminal ciliate protozoan,Entodinium caudatum

Cited by 18 publications

References 33 publications

Review: Ruminal microbiome and microbial metabolome: effects of diet and ruminant host

Review: Ruminal microbiome and microbial metabolome: effects of diet and ruminant host

Interaction of molasses and monensin in alfalfa hay- or corn silage-based diets on rumen fermentation, total tract digestibility, and milk production by Holstein cows

Rumen digestion kinetics, microbial yield, and omasal flows of nonmicrobial, bacterial, and protozoal amino acids in lactating dairy cattle fed fermentation by-products or urea as a soluble nitrogen source

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An NAD⁺-dependent glutamate dehydrogenase cloned from the ruminal ciliate protozoan,Entodinium caudatum