Influence of Dust on <i>Mycoplasma gallisepticum</i> Contact Infection and Body Weight Gain in Chicks, additionally Oil Spray Effect on Dust Control

Abstract

Seventy-two one-week-old crossbred male chicks were divided into three groups (group D: the litter used was saw dust added by sterilized broiler house dust, C: saw dust only, O: oil-sprayed saw dust; litters were renewed weekly), each of which was composed of two sub-groups, and were killed for examinations at 5-weeks-old. Each sub-group included two chicks inoculated intraairsacularally with M. gallisepticum (MG).The following results were obtained.1. A tendency of D>C>O was observed in the number of recipient chicks which showed lesions at infraorbital sinus, trachea or air sacs and from which MG were isolated, and also a significant linear regression of the number of chicks positive to the whole blood agglutination plate test to dust concentration order was.2. According to analyses of variance of results on lesions at air sacs, isolation of MG and the plate test, there were very significant differences among three groups. It was considered, therefore, that MG contact infection might be enhanced by the existence of dust in the atmosphere.3. The influence of contact infection enhanced by dust on body weight gain was not cleared up, but dust itself was not considered to influence chick performances.4. The oil application reduced the amount of dust, but its effect on dust control decreased with length of time after its spray over litter.