Effects of protozoa on bacterial nitrogen recycling in the rumen

K M Koenig, C J Newbold, F M McIntosh, L M Rode

Research output: Contribution to journalArticle

81 Citations (Scopus)

Abstract

The effects of protozoa on ruminal NH3-N kinetics and bacterial N recycling were measured in five sheep (57.6+/-7.1 kg BW, x +/- SD) with ruminal and duodenal cannulas in naturally faunated, defaunated, and refaunated periods. The sheep were fed a diet of 239 g of alfalfa haylage and 814 g of barley concentrate per day (DM basis) divided into 12 equal portions and allocated at 2-h intervals. A pulse dose of 300 mg of 15N as [15N]NH4Cl was administered into the rumen (on d 1 and 15) and 300 mg of 15N as [15N]urea was administered intravenously to the blood (d 8). Enrichment of 15N was measured in ruminal NH3-N, bacterial N, and plasma urea N over a period of 35 h. Total collection of urine was made for 5 d and analyzed for purine derivatives to calculate the flow of microbial N. Ruminal parameters and nutrient digestibilities were also measured. Sheep were defaunated using a rumen washing procedure 50 d prior to measurements in the defaunated period. Sheep were refaunated with ruminal contents from a faunated sheep receiving the same diet. Measurements began 26 d following refaunation, at which time protozoal numbers had returned to those in the originally faunated sheep. Data reported in parentheses are for faunated, defaunated, and refaunated sheep, respectively. Total culturable and cellulolytic bacterial numbers were unaffected by defaunation, but there was an increase in flow of microbial N from the rumen (10.8, 17.3, and 11.1 g N/d; P < .05) in the defaunated period. Flux, irreversible loss, and intraruminal recycling of NH3-N and recycling of NH3-N from plasma urea N were not affected by defaunation. Defaunation had no effect on reducing the absolute amount (13.8, 10.0, and 11.3 g N/d; P > .20) of bacterial N recycling and the percentage of N flux through the bacterial N pool. Total-tract digestion was reduced in defaunated compared with faunated sheep by 8, 17, 15, and 32% for OM, N, NDF, and ADF, respectively. In conclusion, defaunation improved ruminal N metabolism through the enhancement of bacterial protein synthesis, and improvement in the flow of microbial protein to the host animal.

Original languageEnglish
Pages (from-to)2431-45
Number of pages15
JournalJournal of Animal Science
Volume78
Issue number9
Publication statusPrint publication - Sep 2000
Externally publishedYes

Fingerprint

Rumen
recycling
Protozoa
rumen
Sheep
Nitrogen
sheep
nitrogen
Urea
urea
Diet
haylage
Urine Specimen Collection
bacterial proteins
Bacterial Proteins
Medicago sativa
microbial proteins
Hordeum
purines
cannulas

Keywords

  • Animals
  • Bacteria/metabolism
  • Digestion
  • Duodenum/metabolism
  • Eukaryota/metabolism
  • Models, Biological
  • Nitrogen/metabolism
  • Rumen/metabolism
  • Sheep/metabolism

Cite this

Koenig, K. M., Newbold, C. J., McIntosh, F. M., & Rode, L. M. (2000). Effects of protozoa on bacterial nitrogen recycling in the rumen. Journal of Animal Science, 78(9), 2431-45.
Koenig, K M ; Newbold, C J ; McIntosh, F M ; Rode, L M. / Effects of protozoa on bacterial nitrogen recycling in the rumen. In: Journal of Animal Science. 2000 ; Vol. 78, No. 9. pp. 2431-45.
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Koenig, KM, Newbold, CJ, McIntosh, FM & Rode, LM 2000, 'Effects of protozoa on bacterial nitrogen recycling in the rumen', Journal of Animal Science, vol. 78, no. 9, pp. 2431-45.

Effects of protozoa on bacterial nitrogen recycling in the rumen. / Koenig, K M; Newbold, C J; McIntosh, F M; Rode, L M.

In: Journal of Animal Science, Vol. 78, No. 9, 09.2000, p. 2431-45.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effects of protozoa on bacterial nitrogen recycling in the rumen

AU - Koenig, K M

AU - Newbold, C J

AU - McIntosh, F M

AU - Rode, L M

PY - 2000/9

Y1 - 2000/9

N2 - The effects of protozoa on ruminal NH3-N kinetics and bacterial N recycling were measured in five sheep (57.6+/-7.1 kg BW, x +/- SD) with ruminal and duodenal cannulas in naturally faunated, defaunated, and refaunated periods. The sheep were fed a diet of 239 g of alfalfa haylage and 814 g of barley concentrate per day (DM basis) divided into 12 equal portions and allocated at 2-h intervals. A pulse dose of 300 mg of 15N as [15N]NH4Cl was administered into the rumen (on d 1 and 15) and 300 mg of 15N as [15N]urea was administered intravenously to the blood (d 8). Enrichment of 15N was measured in ruminal NH3-N, bacterial N, and plasma urea N over a period of 35 h. Total collection of urine was made for 5 d and analyzed for purine derivatives to calculate the flow of microbial N. Ruminal parameters and nutrient digestibilities were also measured. Sheep were defaunated using a rumen washing procedure 50 d prior to measurements in the defaunated period. Sheep were refaunated with ruminal contents from a faunated sheep receiving the same diet. Measurements began 26 d following refaunation, at which time protozoal numbers had returned to those in the originally faunated sheep. Data reported in parentheses are for faunated, defaunated, and refaunated sheep, respectively. Total culturable and cellulolytic bacterial numbers were unaffected by defaunation, but there was an increase in flow of microbial N from the rumen (10.8, 17.3, and 11.1 g N/d; P < .05) in the defaunated period. Flux, irreversible loss, and intraruminal recycling of NH3-N and recycling of NH3-N from plasma urea N were not affected by defaunation. Defaunation had no effect on reducing the absolute amount (13.8, 10.0, and 11.3 g N/d; P > .20) of bacterial N recycling and the percentage of N flux through the bacterial N pool. Total-tract digestion was reduced in defaunated compared with faunated sheep by 8, 17, 15, and 32% for OM, N, NDF, and ADF, respectively. In conclusion, defaunation improved ruminal N metabolism through the enhancement of bacterial protein synthesis, and improvement in the flow of microbial protein to the host animal.

AB - The effects of protozoa on ruminal NH3-N kinetics and bacterial N recycling were measured in five sheep (57.6+/-7.1 kg BW, x +/- SD) with ruminal and duodenal cannulas in naturally faunated, defaunated, and refaunated periods. The sheep were fed a diet of 239 g of alfalfa haylage and 814 g of barley concentrate per day (DM basis) divided into 12 equal portions and allocated at 2-h intervals. A pulse dose of 300 mg of 15N as [15N]NH4Cl was administered into the rumen (on d 1 and 15) and 300 mg of 15N as [15N]urea was administered intravenously to the blood (d 8). Enrichment of 15N was measured in ruminal NH3-N, bacterial N, and plasma urea N over a period of 35 h. Total collection of urine was made for 5 d and analyzed for purine derivatives to calculate the flow of microbial N. Ruminal parameters and nutrient digestibilities were also measured. Sheep were defaunated using a rumen washing procedure 50 d prior to measurements in the defaunated period. Sheep were refaunated with ruminal contents from a faunated sheep receiving the same diet. Measurements began 26 d following refaunation, at which time protozoal numbers had returned to those in the originally faunated sheep. Data reported in parentheses are for faunated, defaunated, and refaunated sheep, respectively. Total culturable and cellulolytic bacterial numbers were unaffected by defaunation, but there was an increase in flow of microbial N from the rumen (10.8, 17.3, and 11.1 g N/d; P < .05) in the defaunated period. Flux, irreversible loss, and intraruminal recycling of NH3-N and recycling of NH3-N from plasma urea N were not affected by defaunation. Defaunation had no effect on reducing the absolute amount (13.8, 10.0, and 11.3 g N/d; P > .20) of bacterial N recycling and the percentage of N flux through the bacterial N pool. Total-tract digestion was reduced in defaunated compared with faunated sheep by 8, 17, 15, and 32% for OM, N, NDF, and ADF, respectively. In conclusion, defaunation improved ruminal N metabolism through the enhancement of bacterial protein synthesis, and improvement in the flow of microbial protein to the host animal.

KW - Animals

KW - Bacteria/metabolism

KW - Digestion

KW - Duodenum/metabolism

KW - Eukaryota/metabolism

KW - Models, Biological

KW - Nitrogen/metabolism

KW - Rumen/metabolism

KW - Sheep/metabolism

M3 - Article

C2 - 10985419

VL - 78

SP - 2431

EP - 2445

JO - Journal of Animal Science

JF - Journal of Animal Science

SN - 0021-8812

IS - 9

ER -