Serological survey of Toxoplasma gondii, Dirofilaria immitis, Feline Immunodeficiency Virus (FIV) and Feline Leukemia Virus (FeLV) infections in pet cats in Bangkok and vicinities, Thailand

The seroprevalence of Toxoplasma gondii, Dirofilaria immitis (heartworm), feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) infections was examined using serum or plasma samples from 746 pet cats collected between May and July 2009 from clinics and hospitals located in and around Bangkok, Thailand. The samples were tested for heartworm, FIV, and FeLV using a commercial ELISA. Of the 746 samples, 4.6% (34/746) were positive for heartworm antigen, 24.5% (183/746) had circulating FeLV antigen, and 20.1% (150/746) had antibodies against FIV. In addition, the first 348 submitted samples were tested for T. gondii antibodies using a modified agglutination test (MAT, cut off 1:25); 10.1% (35/348) were seropositive. Of the 348 cats sampled for all four pathogens, 11, 10, and 1 were positive for T. gondii antibodies and FIV antibodies, FeLV antigen, or D. immitis antigen, respectively. Of the 35 T. gondii-seropositive cats, 42.9% (15/35) were co-infected with at least one of the other three pathogens. The presence of antibodies to FIV was significantly associated with both age and gender, while FeLV antigen presence was only associated with age. In the case of FIV, males were twice as likely to be infected as females, and cats over 10 years of age were 13.5 times more likely to be infected than cats less than 1 year of age. FeLV antigen was more common in younger cats, with cats over 10 years of age being 10 times less likely to be FeLV positive than cats under 1 year of age. This is the first survey for these four pathogens affecting feline health in Thailand.     

Effect of Water Flow Rate and Stocking Density on Nursing Hatchery-Reared Juvenile Oysters,Crassostrea belcheri in a Semi-Closed Recirculation System

Juveniles of hatchery-reared oysters (Crassostrea belcheri) were grown in a semi-closed recirculation system at water flow rates of 0.5, 1, 2, and 4 l min^?1. Growth rate increased with increasing water flow rate (P < 0.05) over four weeks. No significant differences in survival were found among water flow rates (P > 0.05). Four stocking density treatments were compared: 4, 8, 12, and 16 juveniles cm^?2. Stocking density affected the growth of animals, with higher growth rates obtained at the lower densities. Optimum stocking density based on growth rate was obtained for oysters at 12 juveniles cm^?2. Survival of oysters declined with increasing density (P < 0.05) over four weeks. Among the treatments tested, a water flow rate of 4 l min^?1 and stocking density of 12 juveniles cm^?2 are suitable for nursing hatchery-reared juvenile oysters (C. belcheri) in a semi-closed recirculation system.     

Evaluation of flocculated concentrates from intensive shrimp pond water as a substitute for microalgal concentrates in the nursery culture of juvenile oyster (<Emphasis Type="Italic">Crassostrea belcheri</Emphasis>)

Intensive shrimp pond water typically contains high densities of microalgae and may have a great potential as a substitute for microalgae in the nursery culture of juvenile oysters as this stage needs large amount of microalgae. Two experiments with different phytoplankton composition in flocculated concentrates from shrimp pond water were investigated to compare the effect on preservation and use of flocculated concentrates from intensive shrimp pond as a partial substitute for microalgae concentrates for the nursery culture of juvenile oysters (Crassostrea belcheri) was evaluated. The results show that total crude protein content in flocculated concentrates mostly contain unidentified nanocyanobacteria preserved in refrigerator at 4 °C gradually decreased from the first week in experiment 1, while a slight decrease in crude protein content appeared after the third week in flocculated concentrates dominated by the Bacillariophyceae and unidentified nanocyanobacteria groups in experiment 2. The pheophytin a:chlorophyll a ratio suddenly increased during the third week of storage and most of the fatty acid composition was absent after four weeks of storage in both experiments. Substituting 75 % of microalgal concentrates in feed with flocculated concentrates from shrimp pond water showed no significant differences in growth performance in experiment 1, but higher growth performance in experiment 2 in comparison with control treatment (100 % microalgal concentrates). Our findings indicate that a partial substitution of flocculated concentrates of up to 75 % from shrimp pond water for microalgal concentrates would lead to better growth in juvenile oysters.