The effect of different level of feed intake on therapeutical activity of pyrantel citrate against experimental Trichuris suis infection in pigs

The level of feeding is known to influence the flow rate of digesta through gastrointestinal tract, affecting the time during which orally administere d drug is present at absorptive sites of the intestine. Lower feed intake i n this study was expected to prolong the digesta transit time and allow gre ater quantitative absorption in the small intestine. This should result in lower efficacy against parasites in the large intestine as less drug is pro jected to the colon. Thirteen pigs experimentally infected with Trichuris s uis were divided into 3 groups and given normal (group 1 and 3) or 50 % (gr oup 2) amount of feed. Groups 1 and 2 were treated with pyrantel citrate (2 2 mg/kg). Although not statistically significant, the results of post morte m worm counts 8 days after treatment indicated that efficacy of the drug in group 2 fed a half diet was lower (22 %) compared with group 1 fed normal diet (39 %). Faecal egg counts showed similar reduction of efficacy in grou p 2 (32 % compared with 73 % in group 1).