Butyrate Permeation across the Isolated Ovine Reticulum Epithelium

We hypothesized that, due to the high pH of this compartment, the reticulum epithelium displays particular features in the transport of short-chain fatty acids (SCFA). Ovine reticulum epithelium was incubated in Ussing chambers using a bicarbonate-free buffer solution containing butyrate (20 mmol L−1). p-hydroxymercuribenzoic acid (pHMB), 5-(N-Ethyl-N-isopropyl)amiloride (EIPA), or ouabain were added to the buffer solution as inhibitors of monocarboxylate transporters, sodium-proton-exchangers, or the Na+/K+-ATPase, respectively. The short-circuit current (Isc) and transepithelial conductance (Gt) were monitored continuously while the flux rates of 14C-labelled butyrate were measured in the mucosal-to-serosal (Jmsbut) or serosal-to-mucosal direction (Jsmbut). Under control conditions, the mean values of Isc and Gt amounted to 2.54 ± 0.46 µEq cm−2 h−1 and 6.02 ± 3.3 mS cm−2, respectively. Jmsbut was 2.1 ± 1.01 µmol cm−2 h−1 on average and about twice as high as Jsmbut. Incubation with ouabain reduced Jmsbut, while Jsmbut was not affected. The serosal addition of EIPA did not affect Jmsbut but reduced Jsmbut by about 10%. The addition of pHMB to the mucosal or serosal solution reduced Jmsbut but had no effect on Jsmbut. Mucosally applied pHMB provoked a transient increase in the Isc. The serosal pHMB sharply reduced Isc. Our results demonstrate that butyrate can be effectively transported across the reticulum epithelium. The mechanisms involved in this absorption differ from those known from the rumen epithelium

Butyrate Protects Porcine Colon Epithelium from Hypoxia-Induced Damage on a Functional Level

The large intestinal epithelium is confronted with the necessity to adapt quickly to varying levels of oxygenation. In contrast to other tissues, it meets this requirement successfully and remains unharmed during (limited) hypoxic periods. The large intestine is also the site of bacterial fermentation producing short-chain fatty acids (SCFA). Amongst these SCFA, butyrate has been reported to ameliorate many pathological conditions. Thus, we hypothesized that butyrate protects the colonocytes from hypoxic damage. We used isolated porcine colon epithelium mounted in Ussing chambers, incubated it with or without butyrate and simulated hypoxia by changing the gassing regime to test this hypothesis. We found an increase in transepithelial conductance and a decrease in short-circuit current across the epithelia when simulating hypoxia for more than 30 min. Incubation with 50 mM butyrate significantly ameliorated these changes to the epithelial integrity. In order to characterize the protective mechanism, we compared the effects of butyrate to those of iso-butyrate and propionate. These two SCFAs exerted similar effects to butyrate. Therefore, we propose that the protective effect of butyrate on colon epithelium under hypoxia is not (only) based on its nutritive function, but rather on the intracellular signaling effects of SCFA

Tagungsband: Tiermedizinische Fachangestellte

Das Berufsbild „Tiermedizinische Fachangestellte“ beinhaltet neben Assistenz und fachgerechter Patientenversorgung auch und gerade die Kommunikation mit Patientenbesitzern sowie die Dokumentation der Versorgung. Dementsprechend breit ist auch das Angebot der Vortragsinhalte des Schwerpunktes „Tiermedizinische Fachangestellte“ beim 9. Leipziger Tierärztekongress. Der vorliegende Band fasst diese Inhalte kurz und ansprechend zusammen. Erstmalig erfolgt die Veröffentlichung in diesem Jahr ausschließlich in elektronischer Form. Dies schont nicht nur die Umwelt sondern bietet auch die Möglichkeit, den Band jederzeit griffbereit zu haben

Intravenous infusions of glucose stimulate key lipogenic enzymes in adipose tissue of dairy cows in a dose-dependent manner

The present study was investigated whether increasing amounts of glucose supply have a stimulatory effect on the mRNA abundance and activity of key lipogenic enzymes in adipose tissue of midlactation dairy cows. Twelve Holstein-Friesian dairy cows in midlactation were cannulated in the jugular vein and infused with either a 40% glucose solution (n=6) or saline (n=6). For glucose infusion cows, the infusion dose increased by 1.25%/d relative to the initial net energy for lactation (NEL) requirement until a maximum dose equating to a surplus of 30% NEL was reached on d 24. This maximum dose was maintained until d 28 and stopped thereafter (between d 29-32). Cows in the saline infusion group received an equivalent volume of 0.9% saline solution. Samples of subcutaneous adipose tissue were taken on d 0, 8, 16, 24, and 32 when surplus glucose reached 0, 10, 20, and 30% of the NEL requirement, respectively. The mRNA abundance of fatty acid synthase, cytoplasmic acetyl- coenzyme A synthetase, cytoplasmic glycerol 3-phosphate dehydrogenase-1, and glucose 6-phosphate dehydrogenase showed linear treatment × dose interactions with increasing mRNA abundance with increasing glucose dose. The increased mRNA abundance was paralleled by a linear treatment × dose interaction for fatty acid synthase and acetyl-coenzyme A synthetase enzymatic activities. The mRNA abundance of ATP-citrate lyase showed a tendency for linear treatment × dose interaction with increasing mRNA abundance with increasing glucose dose. The mRNA abundance of all tested enzymes, as well as the activities of fatty acid synthase and acetyl-coenzyme A synthetase, correlated with plasma glucose and serum insulin levels. In a multiple regression model, the predictive value of insulin was dominant over that of glucose. In conclusion, gradual increases in glucose supply upregulate key lipogenic enzymes in adipose tissue of midlactating dairy cows with linear dose dependency. Insulin appears to be critically involved in this regulation. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved