Antibiosis of maize inbred lines to the carmine spider mite, tetranychus cinnabarinus

The antibiosis of tenZea mays L. inbred lines to the carmine spider mite,Tetranychus cinnabarinus (Boisduval) (Acari: Tetranychidae), was evaluated. Two maize inbred lines previously reported as resistant to this spider mite and a susceptible inbred line were compared with B96 (formerly called 41:2504B), reported as being resistant to the two-spotted spider mite T. urticae and to the European corn borer (Ostrinia nubilalis Hübner). Other lines were derived from B96. All lines originated in the U.S.A. and were tested in Israel at two different growth stages. Four days after inoculation of detached leaf squares with adult mites, significant differences in susceptibility were observed among lines. At the 3-leaf stage lines B68, B96, B79, A619, B65, B49 and B64 reduced the average mite daily fecundity by 43%, 64%, 66%, 67%, 77%, 81% and 87%, respectively, as compared with the most susceptible line, B52. At the flowering stage, the average reduction in mite daily fecundity was much lower: inbred lines B64, A619 and B96 reduced the average mite daily fecundity by 48%, 51% and 86%, respectively, whereas the seven other genotypes had an intermediate or a susceptible reaction to the carmine spider mite, with A661 being the most susceptible. Our results show that B96 could be used as a source of resistance in developing improved resistance of inbred lines of maize to carmine spider mites.     

Effects of deoxynivalenol exposure time and contamination levels on rainbow trout

The trend toward using plant‐based ingredients in aquafeeds is set to intensify; however, mycotoxin contamination might be a challenge. Two diets, with deoxynivalenol (DON) levels of 1,166 μg/kg (1.1 DON) and 2,745 μg/kg (2.7 DON), were prepared for short‐term DON exposure (50 days). A third diet with a low DON level of 367 μg/kg (0.3 DON) was prepared for long‐term DON exposure (168 days). Ingestion of DON by trout during both short‐term/high‐dosage exposure (50 days; 1,166 μg/kg and 2,700 μg/kg DON) and long‐term/low‐dosage exposure (168 days; 367 μg/kg DON) impacted growth performance and, to a lesser extent, liver enzyme parameters (2.7 DON). Histopathology showed mild to moderate changes in the liver but not in the other sampled tissues (intestine and kidney). Despite these effects, short‐term exposure of rainbow trout to high doses of DON did not result in increased susceptibility to Yersinia ruckeri. In both the short‐ and long‐term studies, the effects of DON showed a high interindividual variability. The present study confirms that subclinical levels of mycotoxins affect rainbow trout. The effects of such low mycotoxin levels could be masked by other production challenges while still negatively affecting productivity.     

Photochemical Formation of Hydroxyl Radicals in Red Soil-Polluted Seawater on the North of Okinawa Island, Japan

Land development has caused runoff of red soil into the ocean on the north side of Okinawa Island, Japan. In an attempt to clarify the impacts of this “red soil pollution” on the oxidizing power of seawater, we studied the formation of hydroxyl radical (?OH), the most potent oxidant in the environment, in red soil-polluted waters using a 313-nm monochromatic light. ?OH was photochemically formed in the red soil-polluted water samples, and the formation rates of ?OH decreased as salinity increased, i.e., as red soil-polluted river water gets mixed with seawater. The photo-formation rates of ?OH showed good correlations with dissolved Fe concentrations (R ²?=?0.96) and [NO₂ ^?]?+?[NO₃ ^?] concentrations (R ²?=?0.87), while a negative and weak correlation was found with dissolved organic carbon concentrations (R?=??0.78). Theoretical calculation showed that direct photolysis of NO₃ ^?, Fe(OH)²⁺, and hydrogen peroxide all together accounted for less than 10% of the observed ?OH formation in the red soil-polluted waters. Comparison between filtered and unfiltered samples showed that red soil particles were not the main sources of ?OH, and the photolysis of NO₂ ^? could account for at most 78% of the observed ?OH formation rates. We found that the Fenton’s reaction (a reaction between Fe(II) and H₂O₂) could possibly account for the observed formation of ?OH in the red soil-polluted waters.     

Seroepidemiological study of Rift Valley fever (RVF) in animals in Saudi Arabia

Serological prevalence of IgG antibodies against Rift Valley fever (RVFV) virus was investigated in 22 major localities in five different regions of Saudi Arabia where vaccination against RVF virus (RVFV) is not practiced. The study excludes the southwestern region where a major outbreak of RVF occurred in 2000 and where annual vaccination of ruminants is practiced. Sheep and goat IgG-sandwich ELISA were used to test serum samples from sheep and goats, and bovine IgG-sandwich ELISA was used to test cattle sera. A nonspecies-specific, nonantibody isotype-specific ELISA was used to test camel sera. A total of 3,480 sheep, goats, cattle and camels with no previous history of vaccination against RVFV were randomly tested. All tested animals were negative for IgG class antibodies against the virus except four out of 1,508 sheep and three out of 913 goats, which tested positive. All animals were clinically normal and no evidence was found of virus activity in the studied areas. It is, therefore, most likely that those rare positive cases, which constituted 0.002% of the total animals tested, were either false positives or vaccinates smuggled from the outbreak zone. The need for regular monitoring of animals both within the outbreak zone of 2000 and other parts of the kingdom is strongly emphasized.     

Prophylactic and Therapeutic Effects of Oleuropein on Reperfusion-Induced Arrhythmia in Anesthetized Rat

Background:

This study was conducted to reveal that whether i.v. injection of oleuropein, the most potent polyphenolic antioxidant in olive leaf, has any effect on the magnitude of reperfusion arrhythmia in anesthetized rats or not.

Methods:

Eighty male Wistar rats were divided into 8 groups of 10 each: groups 1 and 5 were assigned as the prophylactic and treatment control groups, groups 2 and 6 as the prophylactic and treatment groups with lidocaine (10 mg/kg), groups 3 and 4 as the prophylactic groups with 10 and 50 mg/kg oleuropein (i.v.), and groups 7 and 8 as the treatment groups with 10 and 50 mg/kg oleuropein (i.v.), respectively. Reperfusion injury was induced by 5-min regional ischemia and 15-min reperfusion of left anterior descending coronary artery. Heart rate, blood pressure, and electrocardiogram were monitored throughout the procedure.

Results:

blood pressure was significantly decreased by infusion of 50 mg/kg oleuropein in groups 4 and 8, but unlike the lidocaine as a standard anti-arrhythmic drug in groups 2 and 5 had not significant effect on heart rate. The onset of arrhythmia in groups received oleuropein (groups 3, 4, 7, and 8) was significantly delayed. The mortality rate due to irreversible ventricular fibrillation was also significantly reduced in groups 3, 4, 7, and 8. The effect of lidocaine in groups 2 and 5 was more potent than that in oleuropein group.

Conclusion:

These findings indicate that i.v. injection of oleuropein possibly through its antioxidant activity reduces the magnitude of reperfusion-induced arrhythmia.Key Words: Oleuropein, Arrhythmia, Reperfusion, Rats     

Evaluation of lung pathology in Dirofilaria immitis-experimentally infected dogs treated with doxycycline or a combination of doxycycline and ivermectin before administration of melarsomine dihydrochloride

Adulticide therapy in heartworm (Dirofilaria immitis)-infected dogs can lead to thromboembolism, which can seriously compromise post-treatment health status. Lung pathology following adulticide therapy was evaluated in three groups of experimentally infected dogs. Group 1 was treated with doxycycline at 20 mg/kg per os once daily for 30 days post infection followed by an intramuscular injection of melarsomine dihydrochloride (2.5 mg/kg) at Week 12, followed 1 month later by two injections 24 h apart. Group 2 was treated as described for Group 1, with the addition of ivermectin at 6 mcg/kg given monthly per os for 24 weeks post-infection. Group 3 received melarsomine alone, as described above. All dogs were necropsied at Week 24 and lung pathology was evaluated. Lesion criteria included perivascular inflammation and endothelial proliferation. Lesions were scored by two independent pathologists who were blinded as to treatment. Results indicate that doxycycline treatment alone or combined with ivermectin had lower lesion scores than lungs from dogs who had received melarsomine alone. Dogs that received the combined doxycycline/ivermectin protocol and treated with adulticide showed less severe arterial lesions and the virtual absence of thrombi.     

Low concentrations of BAP and high rate of subcultures improve the establishment and multiplication of somatic embryos in date palm suspension cultures by limiting oxidative browning associated with high levels of total phenols and peroxidase activities

Taking into account the recalcitrance of date palm (Phoenix dactylifera L.) to tissue culture, establishment and proliferation of embryogenic suspension cultures in two date palm cultivars, namely Boufeggouss (BFG) and Bouskri (BSK) was implemented using liquid medium with different concentrations of the 6-benzylaminopurine (BAP) (0.3, 0.4, 0.5 mg/l) and various subculturing times (7 days, 15 days and 20 days). Total phenols and peroxidase activities have been determined and oxidative browning process checked in different cultures. The liquid medium with 0.3 mg/l BAP allowed cell suspension cultures to produce the greater globular embryos and the highest number of somatic embryos in comparison with the other treatment for BFG and BSK date palm cultivars. The low rate of culture transfers (every 15 or 20 days) tended to increase the phenolic contents and peroxidase activities in plant tissue leading to an enhancement of tissues/cells browning and then a decrease in the proliferation of embryogenic cells. The transfer of cultures on fresh medium every 7 days allowed a substantial reduction of tissue/cell oxidative browning, which is related to reduction of phenolic compounds and decrease in peroxidase activities with a resultant increase in the proliferation of embryogenic cells. This result suggests that oxidative browning is mainly peroxidase-based in date palm suspension cultures. Relationships between low concentrations of BAP as cytokinin, high growth of embryogenic cells, low contents of phenolics, decrease of peroxidase activities and oxidative browning process, are discussed, in order to optimize date palm multiplication through somatic embryogenesis and solve recalcitrance of many date palm cultivars to tissue culture.     

Growth, Survival and Feed Conversion Rates of Sea Bream (Sparus aurata) Cultured in Earthen Brackish Water Ponds Fed Different Feed Types

Sparus aurata were cultured during an 8-month period in brackish water (salinity about 25 ppt) in an extensive culture system comprising eight earthen ponds, each with a water surface of 2.1 ha. Initial mean wet weight of fish in all ponds varied from 13.6 ± 1.9 to 19.2 ± 2.6 g/fish. The eight ponds were randomly allocated one of four experimental treatments (two ponds/treatment). In the first treatment, ponds were fertilized monthly with 100 kg urea and 50 kg triple super phosphate. The other treatments (2–4) were fed a locally produced tilapia pellet feed containing 25% crude protein made using different processes. Fish in the second treatment were fed tilapia feed pelleted by compressing machine, whereas in treatments 3 and 4 the pellets were produced by extruder machine (Wenger). Pellets in treatment 3 were floating and in the fourth were semi-sinking. Fish were fed pellets twice daily at 6% of their biomass. The mean final body weight for each treatment respectively was 104.6, 118.9, 156.8 and 158 g. Specific growth rate (SGR) of 0.8, 0.79, 0.99 and 0.95%/day, were obtained in ponds using only inorganic fertilizer, compressed sinking pellets, extruded floating pellets and extruded semi-sinking pellets, respectively. Feed conversion ratios (FCR) for treatments with the extruded tilapia pellets were 2.2 and 2.6 g feed/g gain, which were significantly (P < 0.05) better than treatments with compressed pellets (3.2 g feed/g gain). Production/ha/year were 1389, 1358, 945 and 682 kg fish for the groups fed with extruded floating, extruded semi-sinking, compressed and natural food, respectively. Under the present experimental circumstances, Sparus aurata fed extruded floating tilapia pellets (25% crude protein and 2,600 kcal/g), showed the best productive performance.     

Effects of dietary protein level on spawning performance of Nile tilapia (Oreochromis niloticus) broodstock reared at different water salinities

Effects of dietary protein level and water salinity on spawning performance of Nile tilapia broodstock and growth of their larvae were studied. Four isocaloric (400 kcal/100 g) diets containing 25%, 30%, 35% and 40% crude protein were prepared. The diets were fed to broodfish (25.7 g) reared at three water salinities (0‰, 7‰ and 14‰) at a female/male ratio of 3:1, to satiation twice a day for 195 days. The size at first maturation increased with increasing dietary protein at all salinities. At 25% and 30% protein levels, broodstock reared at 0‰ reached their sexual maturity at bigger sizes than those reared at 7‰ and 14‰. At 0‰, spawning intervals were not significantly affected by dietary protein levels. At 7‰ and 14‰, spawning intervals significantly decreased with increasing dietary protein level. Spawning frequency and number of eggs per spawn were increased with increasing dietary protein level. The total number of spawnings per female and absolute fecundity were better in fish fed 40% protein in freshwater than at 7‰ and 14‰ salinity. The relationship of dietary protein and water salinity on egg size was significant, but showed irregular patterns. The chemical composition of broodstock muscles, eggs and fry were not significantly affected by dietary protein and water salinity, except for body water and crude protein of broodstock which were significantly affected; but showed irregular trends. At each water salinity, egg hatchability was linearly increased with increasing dietary protein level. Eggs produced from broodstock fed 25% protein at 7‰ and 14‰ needed more time for hatching and yolk-sac absorption and resulted in poorer larval weight than those reared in freshwater. Fry growth was improved with increasing protein level at all salinities. This result revealed that 40% dietary protein is required for optimum spawning performance of Nile tilapia reared at 0‰, 7‰ and 14‰ salinity. It also indicated that spawning performance and larval growth were better in freshwater than at 7‰ and 14‰.