Effect of increasing ruminal butyrate on portal and hepatic nutrient flux in steers

Abstract

Six Holstein steers (mean +/- SE BW = 344 +/- 10 kg) fitted with hepatic, portal, and mesenteric vein and mesenteric artery catheters and a ruminal cannula were used in a 6 x 6 Latin square design to evaluate the effects of increasing ruminal butyrate on net portal-drained visceral and hepatic nutrient flux. Steers were fed a 40% brome hay, 60% concentrate diet in 12 portions daily at 1.25 x NEm. Water (control) or butyrate at 50, 100, 150, 200, or 250 mmol/h was supplied continuously via the ruminal cannula. Simultaneous arterial, portal, and hepatic blood samples were taken at hourly intervals from 15 to 20 h of ruminal infusion. Portal and hepatic blood flow was determined by continuous infusion of P-aminohippurate, and net nutrient flux was calculated as the difference between venous and arterial concentrations times blood flow. Ruminal and arterial concentrations and total splanchnic flux of butyrate increased (P less than .01) with increased butyrate infusion. Arterial concentrations of acetate (P less than .10), alpha-amino-N (P less than .05), and glucose (P less than .01) decreased with increased butyrate, whereas arterial beta-hydroxybutyrate (P less than .01) and acetoacetate (P less than .05) increased. Increased butyrate produced an increased portal-drained visceral flux of acetoacetate and an increased net hepatic flux of beta-hydroxybutyrate. Urea N and glucose net portal and hepatic fluxes were not affected by ruminal butyrate. Alpha-amino-N uptake by the liver decreased with increased butyrate (P less than .10). Simple linear regression (r2 = .985) indicated that 25.8% of ruminally infused butyrate appeared in portal blood as butyrate. Only 14% could be accounted for as net portal-drained visceral flux of acetoacetate plus beta-hydroxybutyrate.

Physiology, regulation and multifunctional activity of the gut wall: a rationale for multicompartmental modelling

“…An example is the explanation of the stimulatory effect of propionate and glucose supply on the conversion of butyrate to b-OHbutyrate by rumen epithelia in vitro (Rémond et al 1995;Baldwin & Jesse, 1996), which seems in line with in vivo observations on the effect of propionate and glucose on net portal fluxes (Gross et al 1990b;Krehbiel et al 1992;Seal & Parker, 1994). Principles required for representation of these processes include:…”

“…Studies in which VFA supply was varied by intraruminal infusions demonstrated that a considerable fraction of this supply is not retrieved as a net portal flux of VFA. Infused acetate in dry cows (Huntington et al 1983), propionate in steers (Seal & Parker, 1994) and butyrate in steers (Krehbiel et al 1992) was recovered as a net portal flux for 69, 78 and 40 % (in the latter case 26 % as butyrate and 14 % as b-OH-butyrate). These observations on VFA utilisation by the PDV deviate from the general estimates of 70, 50 and 10 % for acetate, propionate and butyrate as presented in reviews (Bergman, 1990;Bugaut, 1987).…”

“…Predominantly glutamine, glutamate and aspartate are utilised by enterocytes (Britton & Krehbiel, 1993). Other in vivo observations indicate the effects of nutritional factors on AA utilisation by tissues of the stomachs (diet specificity; Reynolds & Huntington, 1988a) and by the PDV (effects of VFA; Krehbiel et al 1992;Nozière et al 2000;Gross et al 1990a). In an overview of several in vivo trials, Huntington (1990) suggested that less than 50 % of AA absorbed is utilised by the PDV in lactating cows, about 50 to 60 % in heifers, and 60 to 75 % in steers.…”

“…The total net appearance of VFA units (acetate þ propionate þ 2 £ butyrate þ 2 £ b-OH-butyrate) was slightly lower on the concentrate diet despite its higher digestibility, indicating a higher rate of VFA utilisation by the stomach tissues. Similarly, Krehbiel et al (1992) established a 28 % lower net portal appearance of AA with intraruminal infusions of butyrate. Finally, Nozière et al (2000) observed a strong proliferative action of intraruminal infusion of butyrate in underfed ewes with much lower (negative) rates of net portal appearance of EAA compared with infusions of mainly acetate and propionate.…”

Quantitative aspects of blood and amino acid flows in cattle

“…Blood flow through the splanchnic tissues Observations were taken from 28 publications concerning growing steers, heifers or cows to build a file of 120 observations (Baird et al, 1975;Casse et al, 1994;Early et al, 1987;Eisemann and Huntington, 1994;Eisemann and Nienaber, 1990;Gross et al, 1988;Guerino et al, 1991;Hammond et al, 1987;Harmon et al, 1988Harmon et al, , 1993Huntington, 1982Huntington, , 1984Huntington, , 1987Huntington and Prior, 1983;Huntington et al, 1983Huntington et al, , 1990Krehbiel et al, 1992;Kreikemeier et al, 1991;Lomax and Baird, 1983;McGuire et al, 1989;Prior ual (1986). Interestingly, these flows could also be fitted with S-shaped curves (Moore, 1985 (Sauvant, 1994), the level of energy intake which increased hepatic and portal blood flows.…”