Influence of an experimental infection of Strongyloides ransomi on performance of pigs.

Sixty-four pigs (average 21.8 kg live weight) were divided into 16 comparable groups of four, each based on sex and body weight, to study the effects of a single infection of Strongyloides ransomi (either 0, 5,000, 10,000 or 20,000 S. ransomi larvae/kg body weight) on performance during a 91-d trial. Final weight, weight gain and average daily gain of pigs not infected were greater (P less than .01) than those of pigs given either 5,000 or 10,000 S. ransomi larvae/kg body weight, which in turn were greater (P less than .01) than those of pigs given 20,000 S. ransomi larvae/kg body weight. Average daily gain for pigs not infected was 40% greater (P less than .01) than that of pigs given 20,000 S. ransomi larvae/kg body weight. Feed required per unit of weight gain was 44% greater for pigs given 20,000 S. ransomi larvae/kg body weight than for pigs not infected, but this difference was not significantly greater due to extreme variation within the group of infected pigs. In each of two trials, eight crossbred barrows (average 20.0 kg in trial 1 and 22.7 kg body weight in trial 2) were examined for the effects of two levels of S. ransomi infections (0 and 10,000 larvae/kg body weight) on digestion and absorption of nutrients and on N balance. Digestion coefficients for dry matter, crude protein and gross energy for pigs not infected were greater (P less than .05) than for those experimentally infected.(ABSTRACT TRUNCATED AT 250 WORDS)