Conservation of freshwater biodiversity in key areas of the Colombian Amazon

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Physiological response to acute endotoxemia in swine: effect of genotype on energy metabolites and leptin

Certain high lean gain swine genotypes have greater sensitivity to pathogen and nonpathogen stressors evident by reduced productivity and increased mortality during disease stress or in suboptimal production environments. Saline (control) and an immunologic challenge (LPS; 25 microg lipopolysaccharide/kg BW) were administered to three genetic populations (each pig used as its own control): high lean (H), moderate lean terminal cross (MT), and moderate lean maternal cross (MM). LPS induced anorexia, and significantly increased body temperature and circulating TNF-alpha, cortisol, and NEFA in all genotypes (P < 0.0004). LPS reduced circulating glucose, insulin, and IGF-1 in all genotypes (P < 0.05). The LPS-induced hypoglycemia was significantly greater in MM versus MT and H pigs (P < 0.03). The hypoinsulinemia was significantly greater in MM versus H pigs (P < 0.02). MM pigs recovered from hypoinsulinemia slower than MT pigs (P < 0.03). Control insulin was higher in H versus MT pigs (P < 0.08), but relative to basal, the insulin response to LPS was similar. Plasma haptoglobin response to LPS was lower for MM versus MT and H pigs (P < 0.02), and tended to be lower in MT versus H pigs (P < 0.09). LPS treatment caused similar decreases in plasma IGF-1 concentrations among genotypes. Ten hours after LPS treatment, leptin mRNA abundance in adipose tissue was significantly reduced (relative to control) in MM and H pigs (P < 0.02) but not in MT pigs (P > 0.05). Physiological differences in leptin, a potent regulator of food intake and energy metabolism, may be important factors in the genetic variation in sensitivity to environmental stress.     

A metabarcoding tool to detect predation of the honeybee Apis mellifera and other wild insects by the invasive Vespa velutina

The invasive Vespa velutina has been widely referred as an effective predator of honeybees. Despite the potential risk to pollination services provision and honey production, there is no accurate quantification and assessment of its real consequences for honeybees. To date, the identification of the honeybee and other insects in the diet of V. velutina has been investigated by direct observation of adult foraging or examination of food pellets. To overcome these limitations, in this study we used a DNA metabarcoding approach to evaluate the usefulness of different types of sample (jaws and stomachs collected from workers and larval faecal pellets taken from the hornet comb) to investigate the predation of V. velutina upon honeybees, and potentially on other insects. Honeybee DNA was identified in all types of samples, but larval faecal pellets retrieved the higher number of reads of honeybee DNA and the largest diversity at all taxonomic levels. Over all samples we could identify 4 orders, 9 families, 6 genera and 1 species of prey. We estimate that collecting 6 workers is sufficient to identify honeybee predation by a colony using worker’s jaws. Stomachs were the least useful sample type to detect honeybee DNA. The presence of honeybee DNA in all analysed colonies irrespective of collection site, and the variety of insect orders detected in the diet support current concerns over the acknowledged negative impact of V. velutina on managed honeybees and its potential threat to pollination services provision.