effect of peroral and intracaecal 3-methylindole administration on the quantitative absorption to the portal vein in growing intact male pigs

• Published in: Canadian journal of animal science Vol. 78; no. 1; pp. 69 - 79
• Main Authors: Laue, A, Hansen-Moller, J, Agergaard, N
• Format: Journal Article
• Language: English
• Published: 1998
• Subjects: blood chemistry; blood flow; boar taint; body weight; cecum; digestive system; dosage; duration; feces; feces composition; intestinal absorption; portal vein; quantitative analysis; skatole; swine
• ISSN: 0008-3984; 1918-1825
• DOI: 10.4141/A96-107

This study intends to extend knowledge on the fate of intestinal 3-methylindole (3MI) in vivo as the substance is a key causative agent in the expression of boar taint in pig carcasses. Eleven multi-catheterized and caecum-fistulated intact male pigs were used to examine the effects of peroral and intracaecal challenges of 1, 5 and 10 mg 3-methylindole per kilogram body weight (BW) on the quantitative net absorption from specific sites of the alimentary canal (AC), measured as 3MI portal net appearance (PNA). Faeces were collected once a day while portal, hepatic and jugular vein as well as arterial blood were collected during the experiments lasting 300 min. Portal blood flow was recorded by ultrasonic blood flow probes. The BW of the pigs averaged 73 to 89 kg at the beginning and end of the experiments. All pigs on the untreated control treatment absorbed 3MI from the AC. Faecal 3MI concentrations did not differ between control and 3MI-treated pigs. On the other hand, an evident difference was observed in the PNA between the controls with an average of 11.2 mg 3MI (300 min)-1 and 3MI-treated animals varying from 23.9 to 308 mg 3MI (300 min)-1. After application of 3MI, the net absorption from the AC to the portal blood plasma increased up to 147 times. Depending on the site of administration and the dosage application, plasma peak values of 3MI occurred within the first 30 min after the challenge. Within the doses of 1 to 10 mg 3MI (kg BW)-1, no absorption plateau was to be reached. The observed rapid absorption of 3MI leads to the assumption that the mechanism is mainly by passive diffusion. Intravenous 3MI injections indicated diffusion from the blood circulation to the intestinal lumen. The site of administering exogenous 3MI was of less importance for the PNA than the dosage applied. This implies that the permeability for 3MI along the AC is identical, no matter where it is introduced. Results indicate a proportional relation between the 3MI dosage administered and the PNA. Finally, it was observed that a) pigs with high (pre-experimental) initial PNAs subsequently also absorbed more 3MI after challenges of additional 3MI, expressed as PNAs; and b) pigs with increasing BW exhibited higher PNAs, indicating a rise of 3MI absorption with advancing age.