The pathogenic potential of five strains of serotype 2 infectious bursal disease virus (IBDV) for specific-pathogen-free chickens was examined. There were no gross or microscopic lesions in the inoculated chickens. Bursa-to-body-weight ratios of IBDV-infected chickens were not significantly different from those of uninfected controls. Virus-neutralizing antibodies to IBDV of serotype 2, but not serotype 1, were detected in infected chickens. This study indicated that the serotype 2 viruses examined were infectious but not pathogenic in chickens.

Day-old poults from hens depleted of Se were fed low-Se basal diets (containing corn, soybean meal, and torula yeast but no added vitamin E) with graded levels of Se supplied by Na2SeO3 or seleno-DL-methionine for 28 and 35 days in Experiments 1 and 2, respectively. Adding .04 ppm Se to the basal diet significantly increased body weight and reduced both the incidence of gizzard myopathy and plasma glutamic-oxaloacetic transaminase (PGOT) activity. Further plasma Se and Se-dependent glutathione peroxidase (SeGSHpx) were elevated by increasing levels of dietary Se. There were no differences in these parameters due to the Se compound fed. Plasma SeGSHpx was significantly correlated with both dietary and plasma Se levels. Poults fed selenomethionine had significantly higher concentrations of Se in the gizzard, breast muscle, and pancreas, but not in the liver and heart, compared to poults fed Na2SeO3. These studies indicate that the utilization of Se in both Na2SeO3 and selenomethionine is approximately equal in young turkey poults.

A rotavirus-like virus (RVLV) was isolated from a diarrheic pig from an Ohio swine herd. This virus infected villous enterocytes throughout the small intestine of gnotobiotic pigs and induced an acute, transitory diarrhea. Complete virions were rarely observed in the intestinal contents of infected animals; the predominant particle detected by immune electron microscopy was a corelike particle 52 nm in diameter. The genome of the porcine RVLV was composed of Il discrete segments of double-stranded RNA that produced an electropherotype distinct from the genome electropherotypes of reovirus, rotavirus, and porcine pararotavirus. Porcine RVLV was antigenically unrelated to rotavirus, porcine pararotavirus, or reovirus but was antigenically related to a bovine RVLV. Rotaviral infections are an important cause of diarrhea in young animals and children (7). Early serological studies indicated that rotaviruses recovered from different species shared a common group antigen (19, 22). However, we recently isolated a virus from a diarrheic pig that was morphologically indistinguishable from rotaviruses but lacked the common group antigen (14) and proposed that this virus tentatively be referred to as porcine pararotavirus (2).

A procedure for extracting rotaviral double-stranded ribonucleic acid (RNA) directly from fecal and intestinal specimens collected from calves and pigs is described. This procedure provides a rapid, simple, reproducible method of obtaining rotaviral double-stranded RNA preparations suitable for electrophoretic analysis in polyacrylamide-agarose composite gels. The rotaviral genome electrophoretic migration pattern produced by double-stranded RNA extracted directly from a specimen by this procedure was qualitatively identical to the electrophoretic migration pattern obtained with double-stranded RNA extracted from purified rotavirus derived from the same specimen. Direct extraction of specimens containing porcine rotavirus-like virus by this procedure gave preparations that had electrophoretic migration patterns similar, but not identical, to the characteristic electrophoretic migration pattern of the rotaviral genome. Sufficient rotaviral double-stranded RNA could be extracted from 6 ml of fecal or intestinal specimen by this procedure to permit 15 or more electrophoretic assays.

A subline (FL) of a long-term growth-selected line (F) of turkeys was established by mass selecting solely for increased shank width at the narrowest point (dew claw). A comparison was made of bone and muscle growth in Line FL (fourth generation of selection), Line F (17th generation of selection), and a randombred control (RBC2, the base population of F) at 8, 16, and 20 wk of age. Also, a sample of the tibiotarsal and femur bones was studied histologically for evidence of pathological conditions. No significant pathological changes were observed in bones from turkeys of the different lines at the ages examined. Samples for histological study were taken at Day 1, 27, 56, 84, 112, and 140 posthatching. Genetic increases in body weight (F and FL lines) resulted in a significant decline in the relative amount of leg muscles from 16 to 20 wk of age while in Line RBC2 the relative amount of leg muscles increased slightly from 16 to 20 wk of age. This resulted in a significant line x age interaction. No significant differences in the amount of leg muscles were detected between turkeys of Lines F and FL. Amount of breast muscles increased consistently with age in all lines. Amount of breast muscles (absolute and as a percentage of body weight) was larger in Line F than in the FL and RBC2 lines. The actual weight of the breast muscles was larger in Line FL than in the RBC2 line but as a percentage of body weight there was no significant difference.(ABSTRACT TRUNCATED AT 250 WORDS)