Site fidelity of spawning sockeye salmon (Oncorhynchus nerka W.) in the presence and absence of olfactory cues

Abstract –  We examined the site fidelity of spawning adult sockeye salmon ( Oncorhynchus nerka ) by tagging and releasing fish in the same stream reach (controls) and displacing them among different but nearby sites ( c . 50 m away). Three sites – two above a stream junction ('upper' reach and 'pond') and one below ('lower' reach) – allowed us to compare the behavior of salmon in the presence and absence of olfactory cues and habitat similarity. Most controls of both sexes (90%) remained in the immediate vicinity of the tagging and release site. When displaced downstream, where the odors of both the upper reach and the pond were detectable, most salmon returned to their former site (65%). Displaced sockeye were more likely to return to the pond from the lower reach than from the upper one ( P  = 0.05), consistent with olfactory orientation and the hypothesis that salmon prefer certain habitats. Salmon displaced from the upper to the lower reach were much more likely to return than those displaced to the pond ( P  < 0.01), consistent with the role of odors in orientation and inconsistent with the habitat choice hypothesis.     

Experimental lead toxicosis in swine

Thirty pigs, weighing 17 to 24 kg, were exposed to lead or sodium acetate orally or intraperitoneally (IP) 6 days each week for 13 weeks. These pigs were extremely tolerant of lead. Only mild clinical signs of lead toxicosis were observed in orally lead-exposed pigs despite blood lead concentrations of up to 290 micrograms/dl. Four IP lead-exposed pigs died, but eight other IP lead-exposed pigs survived the exposure period despite blood lead concentrations up to 14,300 micrograms/dl. Lead exposure caused marked decreases in blood delta-aminolevulinic acid dehydratase activities of all pigs and moderate decreases of blood hemoglobin concentrations, hematocrit percentages, mean corpuscular volumes, mean corpuscular hemoglobin concentrations, and mean corpuscular hemoglobins in IP lead-exposed, but not in orally lead-exposed pigs. Basophilic stippling was observed in erythrocytes of lead-exposed pigs, but not in those of control pigs.     

Die einwirkungen von Fra?giften in subletaler Dosierung auf Spinnerraupen

Ohne Zusammenfassung     

Mechanism of rhythmic synchronous flashing of fireflies. Fireflies of Southeast Asia may use anticipatory time-measuring in synchronizing their flashing

In Thailand, male Pteroptyx malaccae fireflies, congregated in trees, flash in rhythmic synchrony with a period of about 560 +/- 6 msec (at 28 degrees C). Photometric and cinematographic records indicate that the range of flash coincidence is of the order of +/- 20 msec. This interval is considerably shorter than the minimum eye-lantern response latency and suggests that the Pteroptyx synchrony is regulated by central nervous feedback from preceding activity cycles, as in the human "sense of rhythm," rather than by direct contemporaneous response to the flashes of other individuals. Observations on the development of synchrony among Thai fireflies indoors, the results of experiments on phase-shifting in the American Photinus pyralis and comparisons with synchronization between crickets and between human beings are compatible with the suggestion.     

Effects of porcine reproductive and respiratory syndrome vaccination in breeding-age animals

Little is known about the safety and efficacy of extra-label use of the modified live porcine reproductive-and-respiratory syndrome (PRRS) virus vaccine in gestating sows. Our purpose was to determine the impact of vaccination on reproductive performance in 54 herds in Ontario, Manitoba (Canada) and the mid-western United States that were PRRS-positive, PRRS-negative, or concurrently affected by an outbreak of PRRS when initially vaccinated. Majority-vaccinated herds vaccinated ≥50% but <100% of sows at one time, and limit-vaccinated herds vaccinated <50% of sows at one time. Most majority-vaccinated herds did not vaccinate sows in late gestation, and none vaccinated during the initial PRRS outbreak. Numbers of pigs born alive and weaned decreased when pregnant sows were vaccinated. The effect of vaccination on productivity in the gestation following vaccination depended on the vaccination protocol.     

Occurrence of Mycobacterium avium subspecies paratuberculosis and Neospora caninum in Alberta cow-calf operations

Mycobacterium avium subsp. paratuberculosis (MAP) and Neospora caninum (NC) are two pathogens causing important production limiting diseases in the cattle industry. Significant impacts of MAP and NC have been reported on dairy cattle herds, but little is known about the importance, risk factors and transmission patterns in western Canadian cow-calf herds. In this cross-sectional study, the prevalence of MAP and NC infection in southwest Alberta cow-calf herds was estimated, risk factors for NC were identified, and the reproductive impacts of the two pathogens were assessed.     

Gene-expression profiling of calves 6 and 9?months after inoculation with Mycobacterium avium subspecies paratuberculosis

Early detection of Johne’s disease (JD) caused by Mycobacterium avium subspecies paratuberculosis (MAP) is essential to reduce transmission; consequently, new diagnostic techniques and approaches to detect MAP or markers of early MAP infection are being explored. The objective was to identify biomarkers associated with MAP infection at 6 and 9 months after oral inoculation. Therefore, gene expression analysis was done using whole blood cells obtained from MAP-infected calves. All MAP-inoculated calves had a cell-mediated immune response (IFN-γ) to Johnin PPD specific antigens, and 60% had an antibody response to MAP antigens. Gene expression analysis at 6 months after inoculation revealed downregulation of chemoattractants, namely neutrophil beta-defensin-9 like peptide (BNBD9-Like), S100 calcium binding protein A9 (s100A9) and G protein coupled receptor 77 (GPR77) or C5a anaphylatoxin chemotactic receptor (C5a2). Furthermore, BOLA/MHC-1 intracellular antigen presentation gene was downregulated 9 months after inoculation. In parallel, qPCR experiments to evaluate the robustness of some differentially expressed genes revealed consistent downregulation of BOLA/MHC-I, BNBD9-Like and upregulation of CD46 at 3, 6, 9, 12, and 15 months after inoculation. In conclusion, measuring the expression of these genes has potential for implementation in a diagnostic tool for the early detection of MAP infection.

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-014-0096-5) contains supplementary material, which is available to authorized users.