Effects of slaframine on ruminant digestive function: ruminal motility in sheep and cattle

Effect of purified slaframine (SF; 1-acetoxy-6-aminooctahydroindolizine), a parasympathomimetic secretagogue isolated from Rhizoctonia leguminicola, on ruminal motility was investigated in cattle and sheep. In trial 1, four ruminal cannulated wethers, fed a pelleted concentrate and hay diet, were injected intramuscularly with 0, 12, 24 and 48 micrograms SF/kg body weight (BW) in a 4 X 4 Latin-square design. Ruminal motility was recorded 1 h before and 1 to 2 h and 3 to 4 h after SF administration by measuring pressure changes exerted upon a fluid-filled, open-tipped catheter inserted into the dorsal sac of the rumen. The frequencies of both primary and secondary ruminal contractions were decreased as much as 20 to 78% with SF (P less than .05) depending upon the dosage level and time after administration. In trial 2, three ruminal-cannulated steers fed a concentrated diet were injected intramuscularly with 0, 12 and 24 micrograms SF/kg BW in a 3 X 3 Latin-square design. A water-filled balloon inserted into the cranial sac of the rumen was used to measure ruminal pressure changes 1 h before and 1 to 2 h, 3 to 4 h and 7 to 8 after SE administration. Frequency of primary and secondary ruminal contractions decreased with SF as much as 27 to 64% depending on the dosage level and time after administration. The frequency of secondary contractions increased 28% (P less than .05) as compared with control during the 7 to 8 h after administration.(ABSTRACT TRUNCATED AT 250 WORDS)