Serological response in broiler chicks to different commercial Newcastle disease and infectious bronchitis vaccines.

Broiler chicks were administered vaccines against Newcastle disease and infectious bronchitis (both Arkansas and Massachusetts strains) at 2 weeks of age as either primary or secondary vaccinations. The vaccine was administered as a spray at 2 weeks of age to chicks that had received Newcastle disease vaccine alone, bronchitis vaccine alone, both vaccines in combination, or no vaccine at day 1 in the hatchery. The Newcastle disease hemagglutination-inhibition response was significantly lower in chicks receiving Newcastle disease vaccine as a secondary vaccine at 2 weeks than in those receiving the vaccine as a primary vaccination at that age. In contrast, the bronchitis hemagglutination-inhibition response was significantly higher in chicks receiving bronchitis vaccine as a secondary vaccination at 2 weeks than in those receiving the vaccine as a primary vaccination at that age.     

Optics of arthropod compound eye

The extent to which light can escape from one ommatidium into its neighbors in the compound eye has been examined by recording from single receptors during stimulation of single facets. In the "apposition" eye of the drone honeybee and locust, optical interaction is extremely small. In the "superposition" eye of the crayfish, more than half the light captured by the average cell gets in through neighboring facets, even when screening pigments are in the fully lightadapted position.