ABSTRACT
Mycoplasma synoviae (MS) obtained from broiler chickens condemned for airsacculitis was used to determine the influence of air temperature and relative humidity on the severity of airsacculitis produced experimentally. Infectious bronchitis virus was administered to 3-week-old broilers 5 days before aerosol exposure to MS broth cultures, producing extensive airsacculitis within 21-day study periods. High (31-32 C), medium (19-24 C), and low (7-10 C) air temperatures were studied in conjection with high (75-90%), medium (38-56%), and low (23-26%) relative humidities. Airsacculitis was most extensive (45%) at low temperatures regradless of high or medium humidity. The incidence of airsacculitis was greater (39%) at low humidity than at high humidity (17%) when air temperatures were medium. At high temperature, the trend was toward more airsacculitis (12%) at high humidity than (5%) at low humidity. However, the effect of cold air temperature was more dominant than the effect of relative humidity.
Subject(s)
Air Sacs , Coronaviridae Infections/veterinary , Humidity , Mycoplasma Infections/veterinary , Poultry Diseases/etiology , Temperature , Aerosols , Air/analysis , Ammonia/analysis , Animals , Bronchitis/veterinary , Coronaviridae Infections/complications , Coronaviridae Infections/etiology , Female , Infectious bronchitis virus , Injections , Male , Mycoplasma Infections/complications , Mycoplasma Infections/etiology , TracheaABSTRACT
White rock chicks were fed a commercial crumbles ration with approximately 1.0 p.p.m. of the active ingreient of technical grade dieldrin added to it. The treated feed was replaced by uncontaminated feed at various times from two to eight weeks of age. Equations were computed to describe the accumulation and depletion of the insecticide in visceral adipose tissue. Accumulations in females were described by polynomial equations with significant quadratic coefficients which indicated that the rate of accumulation leveled off between six and eight weeks. Accumulation rates in males were essentially linear through ten weeks. After removal of dieldrin from the feed, insecticide depletion from fat could be described in both sexes by equations for power curves. Replacement of contaminated feed with uncontaminated feed by two or three weeks of age resulted in concentrations at control or background levels by eight weeks of age. Replacement of contaminated feed with non-contaminated feed at ages later than three weeks did not bring concentrations below those acceptable as non-hazardous for human consumption.
