Protein recycling in growing rabbits

contribution of microbial lysine to amino acid metabolism

Alvaro Belenguer, J Balcells, J A Guada, M Decoux, Eric Milne

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

To study the absorption of microbial lysine in growing rabbits, a labelled diet (supplemented with (NH4Cl)-N-15) was administered to six animals (group ISOT); a control group (CTRL, four rabbits) received a similar, but unlabelled, diet. Diets were administered for 30 d. An additional group of six animals were fed the unlabelled diet for 20 d and then the labelled diet for 10 d while wearing a neck collar to avoid caecotrophy (group COLL), in order to discriminate it from direct intestinal absorption. At day 30 animals were slaughtered and caecal bacteria and liver samples taken. The N-15 enrichment in amino acids of caecal bacteria and liver were determined by GC-combustion/isotope ratio MS. Lysine showed a higher enrichment in caecal microflora (0.925 atom% excess, APE) than liver (0.215 APE) in group ISOT animals, confirming the double origin of body lysine: microbial and dietary. The COLL group showed a much lower enrichment in tissue lysine (0.007 (se 0.0029) APE for liver). Any enrichment in the latter animals was due to direct absorption of microbial lysine along the digestive tract, since recycling of microbial protein (caecotrophy) was avoided. In such conditions liver enrichment was low, indicating a small direct intestinal absorption. From the ratio of [N-15]lysine enrichment between liver and bacteria the contribution of microbes to body lysine was estimated at 23%, with 97% of this arising through caecotrophy. Absorption of microbial lysine through caecotrophy was 119 (se 4.0) mg/d, compared with 406 (se 1.8) mg/d available from the diet. This study confirms the importance of caecotrophy in rabbit nutrition (15% of total protein intake).

Original languageEnglish
Pages (from-to)763-770
Number of pages8
JournalBritish Journal of Nutrition
Volume94
Issue number5
DOIs
Publication statusPublished - Nov 2005

Keywords

  • rabbit
  • caecotrophy
  • microbial lysine
  • N-15 kinetics
  • nonstarch polysaccharides
  • whole-body
  • availability
  • pigs
  • digestibility
  • homeostasis
  • excretion
  • bacteria
  • nitrogen
  • animals

Cite this

Protein recycling in growing rabbits : contribution of microbial lysine to amino acid metabolism. / Belenguer, Alvaro; Balcells, J ; Guada, J A ; Decoux, M ; Milne, Eric.

In: British Journal of Nutrition, Vol. 94, No. 5, 11.2005, p. 763-770.

Research output: Contribution to journalArticle

Belenguer, Alvaro ; Balcells, J ; Guada, J A ; Decoux, M ; Milne, Eric. / Protein recycling in growing rabbits : contribution of microbial lysine to amino acid metabolism. In: British Journal of Nutrition. 2005 ; Vol. 94, No. 5. pp. 763-770.
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abstract = "To study the absorption of microbial lysine in growing rabbits, a labelled diet (supplemented with (NH4Cl)-N-15) was administered to six animals (group ISOT); a control group (CTRL, four rabbits) received a similar, but unlabelled, diet. Diets were administered for 30 d. An additional group of six animals were fed the unlabelled diet for 20 d and then the labelled diet for 10 d while wearing a neck collar to avoid caecotrophy (group COLL), in order to discriminate it from direct intestinal absorption. At day 30 animals were slaughtered and caecal bacteria and liver samples taken. The N-15 enrichment in amino acids of caecal bacteria and liver were determined by GC-combustion/isotope ratio MS. Lysine showed a higher enrichment in caecal microflora (0.925 atom{\%} excess, APE) than liver (0.215 APE) in group ISOT animals, confirming the double origin of body lysine: microbial and dietary. The COLL group showed a much lower enrichment in tissue lysine (0.007 (se 0.0029) APE for liver). Any enrichment in the latter animals was due to direct absorption of microbial lysine along the digestive tract, since recycling of microbial protein (caecotrophy) was avoided. In such conditions liver enrichment was low, indicating a small direct intestinal absorption. From the ratio of [N-15]lysine enrichment between liver and bacteria the contribution of microbes to body lysine was estimated at 23{\%}, with 97{\%} of this arising through caecotrophy. Absorption of microbial lysine through caecotrophy was 119 (se 4.0) mg/d, compared with 406 (se 1.8) mg/d available from the diet. This study confirms the importance of caecotrophy in rabbit nutrition (15{\%} of total protein intake).",
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T1 - Protein recycling in growing rabbits

T2 - contribution of microbial lysine to amino acid metabolism

AU - Belenguer, Alvaro

AU - Balcells, J

AU - Guada, J A

AU - Decoux, M

AU - Milne, Eric

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N2 - To study the absorption of microbial lysine in growing rabbits, a labelled diet (supplemented with (NH4Cl)-N-15) was administered to six animals (group ISOT); a control group (CTRL, four rabbits) received a similar, but unlabelled, diet. Diets were administered for 30 d. An additional group of six animals were fed the unlabelled diet for 20 d and then the labelled diet for 10 d while wearing a neck collar to avoid caecotrophy (group COLL), in order to discriminate it from direct intestinal absorption. At day 30 animals were slaughtered and caecal bacteria and liver samples taken. The N-15 enrichment in amino acids of caecal bacteria and liver were determined by GC-combustion/isotope ratio MS. Lysine showed a higher enrichment in caecal microflora (0.925 atom% excess, APE) than liver (0.215 APE) in group ISOT animals, confirming the double origin of body lysine: microbial and dietary. The COLL group showed a much lower enrichment in tissue lysine (0.007 (se 0.0029) APE for liver). Any enrichment in the latter animals was due to direct absorption of microbial lysine along the digestive tract, since recycling of microbial protein (caecotrophy) was avoided. In such conditions liver enrichment was low, indicating a small direct intestinal absorption. From the ratio of [N-15]lysine enrichment between liver and bacteria the contribution of microbes to body lysine was estimated at 23%, with 97% of this arising through caecotrophy. Absorption of microbial lysine through caecotrophy was 119 (se 4.0) mg/d, compared with 406 (se 1.8) mg/d available from the diet. This study confirms the importance of caecotrophy in rabbit nutrition (15% of total protein intake).

AB - To study the absorption of microbial lysine in growing rabbits, a labelled diet (supplemented with (NH4Cl)-N-15) was administered to six animals (group ISOT); a control group (CTRL, four rabbits) received a similar, but unlabelled, diet. Diets were administered for 30 d. An additional group of six animals were fed the unlabelled diet for 20 d and then the labelled diet for 10 d while wearing a neck collar to avoid caecotrophy (group COLL), in order to discriminate it from direct intestinal absorption. At day 30 animals were slaughtered and caecal bacteria and liver samples taken. The N-15 enrichment in amino acids of caecal bacteria and liver were determined by GC-combustion/isotope ratio MS. Lysine showed a higher enrichment in caecal microflora (0.925 atom% excess, APE) than liver (0.215 APE) in group ISOT animals, confirming the double origin of body lysine: microbial and dietary. The COLL group showed a much lower enrichment in tissue lysine (0.007 (se 0.0029) APE for liver). Any enrichment in the latter animals was due to direct absorption of microbial lysine along the digestive tract, since recycling of microbial protein (caecotrophy) was avoided. In such conditions liver enrichment was low, indicating a small direct intestinal absorption. From the ratio of [N-15]lysine enrichment between liver and bacteria the contribution of microbes to body lysine was estimated at 23%, with 97% of this arising through caecotrophy. Absorption of microbial lysine through caecotrophy was 119 (se 4.0) mg/d, compared with 406 (se 1.8) mg/d available from the diet. This study confirms the importance of caecotrophy in rabbit nutrition (15% of total protein intake).

KW - rabbit

KW - caecotrophy

KW - microbial lysine

KW - N-15 kinetics

KW - nonstarch polysaccharides

KW - whole-body

KW - availability

KW - pigs

KW - digestibility

KW - homeostasis

KW - excretion

KW - bacteria

KW - nitrogen

KW - animals

U2 - 10.1079/BJN20051508

DO - 10.1079/BJN20051508

M3 - Article

VL - 94

SP - 763

EP - 770

JO - British Journal of Nutrition

JF - British Journal of Nutrition

SN - 0007-1145

IS - 5

ER -