Portal Recovery of Intraruminally Infused Short-chain Fatty Acids in Sheep

Kristensen, Niels Bastian; Danfær, A.; Tetens, Vilhelm; Agergaard, N.

doi:10.1080/09064709609410921

Cited by 52 publications

(80 citation statements)

References 18 publications

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“…The rumen production rates of the individual VFA calculated from the propionate and butyrate with the NTM were comparable within the same intake level. This suggested similar fractional absorption rates between the different VFA and was in agreement with other results (Kristensen et al 1996;Nozière et al 2000). In addition, Dijkstra et al (1993) observed equal rumen disappearance rates for acetate, propionate and butyrate at rumen pH in the region of 7, close to those (6 : 5) measured in our study.…”

Section: Intake Levelsupporting

confidence: 93%

Comparison of non-tracer and tracer methods for determination of volatile fatty acid production rate in the rumen of sheep fed on two levels of intake

Martin

Kristensen²,

Huhtanen³

2001

Br J Nutr

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The aim of the present work was to estimate volatile fatty acid (VFA) production rate in the rumen of sheep fed two levels of intake using both a tracer (TM; by isotope dilution) and a nontracer method (NTM; by supplementary infusion) in steady-state conditions. Six wethers received a diet containing 700 g lucerne hay and 300 g ground maize/kg in eight equal meals at 3 h intervals per d. The diet (9 : 8 MJ metabolizable energy (ME)/kg DM) was offered at 90 % ad libitum consumption (high intake, HI) or 45 % ad libitum consumption (low intake, LI) in a 2 Â 2 crossover design. Each sheep received five intrarumen VFA solutions infused continuously for 24 h at rates of 250 ml and 165 ml/h for the HI and LI respectively. The first infusion, considered as a control treatment (Con), consisted of a solution of [1-13 C]propionate (7 mmol/d). The four other solutions were isoenergetic (1 : 9 MJ ME/kg DM intake) mixtures of unlabelled propionate (C 3 ) and butyrate (C 4 ) at different levels: 0 : 90 mol C 4 /kg DM intake; 0 : 60 mol C 4 1 0 : 45 mol C 3 /kg DM intake; 0 : 30 mol C 4 1 0 : 90 mol C 3 /kg DM intake; 1 : 35 mol C 3 /kg DM intake. The VFA infusions did not affect rumen fermentation of the basal diet (pH, osmotic pressure, protozoa numbers), and comparable DM digestibility of the diet among the different treatments was observed. Both estimation methods demonstrated a similar increase (1 : 7-fold) in the rumen VFA production rate of sheep fed at intakes varying between 0 : 9 to 1 : 7 times maintenance. Irrespective of the intake level, the rumen production rate of individual VFA was on average 1 : 5-fold higher when estimated by the TM compared with the NTM. Rumen VFA production rates estimated by the NTM and TM represented 80 % and 120 % ME intake respectively. The difference between NTM and TM estimates seems likely to be caused mainly by overestimation of the VFA production rates by the TM. Rumen: Volatile fatty acids: Production rate: Intake levelVolatile fatty acids (VFA) are the main energy source for ruminants, contributing 50-80 % of the total energy supply (Thomas & Clapperton, 1972;Sutton, 1985). The major part (75 %) of the rumen VFA disappears across the reticulorumen wall with a variable absorption rate, especially when concentrate diets are fed. This means that the rumen VFA concentration is not directly proportional to their production rate (Esdale et al. 1968;Sharp et al. 1982). Assessment of the quantitative contribution of VFA to ruminant nutrition requires measurements of the VFA production rate in the rumen. In general, two groups of techniques are employed for in vivo determination of rumen VFA production rates: tracer methods (TM) and non-tracer methods (NTM). TM usually use an isotope-dilution technique of a solution of VFA labelled with radioactive isotopes ( 14 C, 3 H) and continuously infused into the rumen at a constant rate (Leng & Leonard, 1965;Leng & Brett, 1966;Bruce et al. 1987). The radioactivity of these compounds has been considered to be a major disadvantage of in vivo experime...

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Section: Intake Levelsupporting

confidence: 93%

Comparison of non-tracer and tracer methods for determination of volatile fatty acid production rate in the rumen of sheep fed on two levels of intake

Martin

Kristensen²,

Huhtanen³

2001

Br J Nutr

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“…The failure to account for possible metabolites of propionate and butyrate, however, is of minor importance quantitatively when compared with acetate, which is the major contributor to the energy loss associated with SCFA absorption. The comprehensive data on acetate metabolism reported by Kristensen et al (1996) were entirely consistent with literature values for the portal recovery of acetate (see Seal & Reynolds, 1993). All of the available data indicate that the measured portal recovery of acetate is, at most, 70 %.…”

Section: Utilization Of Short-chain Fatty Acids By the Portal-drainedsupporting

confidence: 81%

Perspectives on ruminant nutrition and metabolism. II. Metabolism in ruminant tissues

Annison

Bryden

1999

Nutr. Res. Rev.

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The discovery of the dominance of short-chain fatty acids as energy sources in the 1940s and 1950s, as discussed in part I of this review (Annison & Bryden, 1998) led to uncertainties concerning the interrelationships of glucose and acetate in ruminant metabolism. These were resolved in the following decade largely by use of 14 C-labelled substrates. Although only small amounts of glucose are absorbed in most dietary situations, glucose availability to ruminant tissues as measured by isotope dilution was shown to be substantial, indicating that gluconeogenesis is a major metabolic activity in both fed and fasted states. Studies with 14 C-labelled glucose and acetate revealed that in contrast to non-ruminants, acetate and not glucose is the major precursor of long-chain fatty acids in ruminant tissues. Interest in the measurement of energy metabolism in livestock grew rapidly from the 1950s. Most laboratories adopted indirect calorimetry and precise measurements of the energy expenditure of ruminants contributed to the development of new feeding systems. More recently, alternative approaches to the measurement of energy expenditure have included the use of NMR spectroscopy, isotope dilution and the application of the Fick principle to measure O 2 consumption in the whole animal and in de®ned tissues. The re®nement of the classical arterio-venous difference procedure in the study of mammary gland metabolism in the 1960s, particularly when combined with isotope dilution, encouraged the use of these methods to generate quantitative data on the metabolism of a range of de®ned tissues. The recent introduction of new methods for the continuous monitoring of both blood¯ow and blood O 2 content has greatly increased the precision and scope of arterio-venous difference measurements. The impact of data produced by these and other quantitative procedures on current knowledge of the metabolism of glucose, short-chain fatty acids and lipids, and on N metabolism, is outlined. The role of the portal-drained viscera and liver in N metabolism is discussed in relation to data obtained by the use of multi-catheterized animals. Protein turnover, and the impact of stress (physical, social and disease related) on protein metabolism have been reviewed. The growth of knowledge of mammary gland metabolism and milk synthesis since the ®rst quantitative studies in the 1960s has been charted. Recent ®ndings on the regulation of amino acid uptake and utilization by the mammary gland, and on the control of milk secretion, are of particular interest and importance.

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“…A 40 ml homogenized sample was centrifuged, and the pH was measured in the supernatant before stabilizing with 5% meta-phosphoric acid. Concentrations of acetic acid, propionic acid and butyric acid were analyzed by gas chromatography as described by Kristensen et al (1996). Content of ammonia was determined using a Cobas Mira auto-analyzer (Triolab A/S, Broendby, Denmark) and a kit based on glutamate dehydrogenase (AM 1015; Randox Laboratories Ltd, Crumlin, UK).…”

Section: Methodsmentioning

confidence: 99%

Evaluation of physical structure value in spring-harvested grass/clover silage and hay fed to heifers

Schulze

Nørgaard

Byskov

et al. 2015

Animal

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The physical structure value of conserved grass/clover forages of spring harvest was evaluated by assessing effects of harvest time, conservation method, iNDF/NDF ratio and NDF intake (NDFI) per kg BW on chewing activity and fecal particle size in dairy heifers. A mixed sward consisting of ryegrass (Lolium perenne), red clover (Trifolium pratense) and white clover (Trifolium repens) was harvested in 2009 on May 9 (early) and 25 (late), and both cuts were conserved as silage and hay. The early silage, early hay, late silage and late hay contained dry matter (DM) of 454, 842, 250 and 828 g/kg, and NDF of 315, 436, 414 and 503 g/kg DM, respectively. Forages were fed as sole feed to four Jersey heifers of 435 ± 30 kg BW in a 4 × 4 Latin square experiment. Feeding level was 90% of individual ad libitum intake, divided equally across two daily meals offered at 0800 and 1530 h. Chewing activity was estimated from recorded jaw movements (JM) oscillations continuously logged for 96 h and summarized per 24 h as mean effective rumination time and eating time. Eating behavior was further observed during four 20-min test meals. Weight proportion of large feces particles (>1.0 mm) and geometric mean fecal particle size (GPS) were calculated. Potentially indigestible NDF (iNDF) was estimated by incubation for 288 h in situ. The daily DM intake (DMI) decreased with progressing maturity at harvest ( P < 0.001) while daily NDFI was unaffected by harvest time ( P > 0.05). Earlier harvest led to less rumination per kg NDFI ( P < 0.01), similar eating time per kg NDFI ( P > 0.05) and similar proportion of large particles ( P > 0.01) compared with later harvest. Rumination time per kg NDFI decreased with higher NDFI per kg BW ( P < 0.001) and with lower iNDF/NDF ratio ( P < 0.01). Content and potential digestibility of NDF was greater in hay than in silage from the same harvest probably due to field loss and therefore confounded effects of conservation method. This study of high digestibility grass/clover silage and hay showed that NDF content and NDFI per kg BW affect fecal particle size and rumination time per kg NDF, and suggests implementation of NDFI per kg BW in systems evaluating physical structure in diets.

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Portal Recovery of Intraruminally Infused Short-chain Fatty Acids in Sheep

Cited by 52 publications

References 18 publications

Comparison of non-tracer and tracer methods for determination of volatile fatty acid production rate in the rumen of sheep fed on two levels of intake

Comparison of non-tracer and tracer methods for determination of volatile fatty acid production rate in the rumen of sheep fed on two levels of intake

Perspectives on ruminant nutrition and metabolism. II. Metabolism in ruminant tissues

Evaluation of physical structure value in spring-harvested grass/clover silage and hay fed to heifers

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