Biological characterization of African swine fever virus genotype II strains from north-eastern Estonia in European wild boar.

Due to its impact on animal health and pig industry, African swine fever (ASF) is regarded as one of the most important viral diseases of pigs. Following the ongoing epidemic in the Transcaucasian countries and the Russian Federation, African swine fever virus was introduced into the Estonian wild boar population in 2014. Epidemiological investigations suggested two different introductions into the southern and the north-eastern part of Estonia. Interestingly, outbreak characteristics varied considerably between the affected regions. While high mortality and mainly virus-positive animals were observed in the southern region, mortality was low in the north-eastern area. In the latter, clinically healthy, antibody-positive animals were found in the hunting bag and detection of virus was rare. Two hypotheses could explain the different behaviour in the north-east: (i) the frequency of antibody detections combined with the low mortality is the tail of an older, so far undetected epidemic wave coming from the east, or (ii) the virus in this region is attenuated and leads to a less severe clinical outcome. To explore the possibility of virus attenuation, a re-isolated ASFV strain from the north-eastern Ida-Viru region was biologically characterized in European wild boar. Oronasal inoculation led to an acute and severe disease course in all animals with typical pathomorphological lesions. However, one animal recovered completely and was subsequently commingled with three sentinels of the same age class to assess disease transmission. By the end of the trial at 96 days post-initial inoculation, all animals were completely healthy and neither virus nor viral genomes were detected in the sentinels or the survivor. The survivor, however, showed high antibody levels. In conclusion, the ASFV strain from north-eastern Estonia was still highly virulent but nevertheless, one animal recovered completely. Under the experimental conditions, no transmission occurred from the survivor to susceptible sentinel pigs.

Gas chromatographic analysis of coyote and magpie tissues for residues of compound 1080 (sodium fluoroacetate).

Tissues of coyotes and magpies administered known dosages of 1080 were analyzed for residues by an analytical method specifying gas chromatography and electron capture detection. The repeatability of the method was determined for the replicate analyses of coyote muscle tissue samples aged under different storage conditions. The average coefficient of variation (CV) was 6% for quadruplicate determinations of 1080 in fresh tissues, 12-14% for samples stored at - 10 degrees C for 30-60 days, and 24% for samples aged for 7 days at ambient temperatures. The larger CV value obtained for stored samples is attributed more to greater sample variability than to less precision of the analytical method. Residues of 1080 appear to be relatively stable in tissues; there was essentially no change in the concentration of 1080 in samples stored up to 28 days at ambient temperature. Residue levels in the muscle, heart, kidney, and intestine were comparable, slightly lower in the liver, and much higher in the stomach. The concentration of 1080 in the muscle tissue was related to the administered dosages. Correlation analyses of dosages and residue levels in coyote muscle tissue showed a correlation coefficient of 0.99 for 1080 administered by gavage, and 0.88 for 1080 administered by bait. A correlation coefficient of 0.99 was observed between dosages and mean residues in the breast muscle tissues of magpies. The average CV value was 3.5% for duplicate analyses of 1 g samples of magpie tissues.

Comparative digestibility of acid detergent fiber by laboratory albino and wild Polynesian rats.

The effects of adding 5%, 10%, and 15% acid detergent fiber to a nonfibrous basal diet were examined in a comparative feeding study with Polynesian rats (Rattus exulans) and laboratory rats. Digestibility coefficients for dry matter, crude protein, and gross energy declined significantly in both species as fiber content increased, but averaged significantly lower in the Polynesian than in the laboratory rat. Fiber digestibility was not significantly affected by fiber level but was by species, with the Polynesian rat having the higher digestibility coefficients.

Cholesterol metabolism in the chicken.

Four hundred and eighty, sexed (White Leghorn) chicks were divided so that each sex was fed one of eight rations to determine the effect of sex, dietary cholesterol, and stearic, oleic, and/or linoleic acid on cholesterol deposition in blood, liver and aortic tissues. After 5 months on the dietary regimen, 3 cockerels from each of the rations were orally administered 100 mC. sodium-1-C14-acetate and 200 mC. cholesterol-1,2-H3 to determine whether body tissues contained cholesterol from endogenous or exogenous origin. After 5 months on the experimental rations it was observed that male birds had higher free cholesterol levels than did females. The addition of cholesterol (2%) and fatty acids (6%) to ration increased free cholesterol levels in liver and aorta. Cholesterol stored in livers and aortas occurs principally as free cholesterol while blood cholesterol was in esterified form. Cholesterol levels in both liver and aorta are primarily of endogenous origin.