The electrophysiological response of fish to hypoxia

Electrophysiological signals, associated with the respiration activity, were recorded from tilapia hybrid (Oreochromis auratus × Oreochromis niloticus) held individually in electrode chambers. The signals were monitored and processed in real time to yield a set of indices characterizing the energy and frequency of the signal. The fish were exposed to hypoxia and responded by increasing energy parameters, while variations in frequency parameters did not show a clear trend. It seems that tilapia compensates the shortage in oxygen by increasing the tidal volume without varying the ventilation frequency. The technique developed has potential for use as a sensitive monitoring tool for various stressors, which could assist fish farming management.     

Efficacy of a new slow-release volatile system against <Emphasis Type="Italic">Aphis gossypii</Emphasis> Glover (Hemiptera: Aphididae) on cucumber, <Emphasis Type="Italic">Cucumis sativus</Emphasis> L.

Many arthropod agricultural pests have become resistant to pesticides through inappropriate usage. A consequence of this resistance is often cross-resistance with other pesticides with similar or related modes of actions. As a result of increasing pesticide resistance, a movement to alternative, ‘green’ botanical pesticides has been growing. A new formulation of volatile oils, extracted from a variety of plants allows for slow-release and longer duration in the field. In this publication we present results of the efficacy of one of these products against the cotton aphid Aphis gossypii on cucumber plants in replicated choice tests. The slow release Ap2, a Bio-Pel product from Newseal Mineral and Coatings Ltd. (hereafter Newseal), significantly reduced the population of aphids on test plants and prevented their movement upwards on the plant. Additionally, four Newseal products caused no mortality to the aphid parasitoid Aphidius colemani or to the generalist predator, Orius laevigatus.     

Seroprevalence of Neospora spp. among asymptomatic horses, aborted mares and horses demonstrating neurological signs in Israel

Sera from 800 asymptomatic horses were examined for the presence of antibodies to Neospora caninum by immunofluorescence antibody test (IFAT). The presence of antibodies to N. caninum was also tested in sera from 52 mares that had aborted and 40 horses exhibiting neurological signs. A total of 95 (11.9%) of the 800 sera had antibodies for Neospora. Significantly higher seropositivity was obtained from horses that had neurological signs (21.2%) and from aborted mares (37.5%). There was significant linear-by-linear association between age and seropositivity. This is the first serologic survey for Neospora spp. antibodies performed on horses from the Middle East and the first to report significant difference in seropositivity between asymptomatic horses and horses exhibiting neurological signs.