Occurrence of anti-<Emphasis Type="Italic">Toxoplasma gondii</Emphasis> antibodies in female cattle in south-west of Iran

Toxoplasmosis, caused by Toxoplasma gondii, is a significant disease in livestock and humans. In Iran, studies shows that T. gondii infection in humans is relatively high and prevalence is associated mainly with consumption of undercooked meat or meat products. We have examined 450 serum samples from female cattle distributed over all Ahvaz, the center of Khouzestan province, south-west of Iran. IgG antibodies to T. gondii were assayed by the modified agglutination test using whole tachyzoites of T. gondii, and found in 71 (15.77%) of 450 cattle with titers of 1:25 in 38, 1:50 in 18, 1:100 in 11, 1:200 in three and 1:400 in one. Titers of antibodies were decreased in cattle over 2 years old. These results indicate that T. gondii infection in cattle of Khouzestan is relatively considerable, but not very high and consumption of beef may be a source of infection for humans in south-west of Iran.     

Polyculture of western white shrimp,Litopenaeus vannamei Boone, 1931 with Grey mullet,Mugil cephalus Linnaeus, 1758 controls external parasites of western white shrimp

The main aim of this study was to examine the effects of a polyculture system on the control of the external parasites of western white shrimp, Litopenaeus vannamei. To this end, the western white shrimp postlarvae (PLs) were stocked in nine earthen ponds (600 m²) at a density of 20 PLs m^?2 and reared for 4 months. After 40 days of shrimp stocking, Mullets, Mugil cephalus, were stocked at various densities including: control (0 fish/100 m² pond), treatment 1 (T₁: 2 fish/100 m² pond) and treatment 2 (T₂: 4 fish/100 m² pond). Over the course of the experiment, the external parasites of shrimps were investigated by the preparation of a wet mount from the gill tissue. Based on the obtained results, totally two genera of protozoan parasites, i.e. Zoothamnium sp. and Epistylis sp., were identified over the course of the experiment. In all experimental groups, the incidence and abundance of Zoothamnium sp. was significantly higher than Epistylis sp. (P < 0.05). Also, mean incidence per cent and mean abundance of Zoothamnium sp. and Epistylis sp. were significantly lower in the polyculture treatments (T₁ and T₂) compared to the monoculture group (control) (P < 0.05). Throughout this experiment, the total organic matter (TOM %) content of the bottom sediments and biological oxygen demand (BOD₅ mg L^?1) of water samples in the polyculture ponds were significantly lower than the monoculture group (P < 0.05). In contrast, the polyculture ponds had a higher concentration of water dissolved oxygen (O₂ mg L^?1) compared to the monoculture (P < 0.05). In conclusion, our results show that mullet as a secondary farmed species can reduce indirectly the parasitic pollution of western white shrimp probably through reducing the total organic matters in water and sediments and improving the water quality parameters.     

Stimulating and toxicity effects of nickel on growth,yield, and fruit quality of cucumber supplied with different nitrogen sources

Limited information is available on biological effects of various levels of nickel (Ni) (deficiency to toxicity levels) on growth and yield of certain crops, particularly vegetables. In this sand‐culture study, we investigated the effects of four levels of Ni (0, 50, 100, and 200 μM) on growth, yield, and fruit‐quality attributes of two cucumber cultivars (Cucumis sativus L. cvs. Super Dominus and Negin) supplied with urea or NH₄NO₃ as nitrogen source. Addition of 50 μM Ni to the nutrient solution resulted in a significant increase of shoot and root dry‐matter yield of cv. Negin although this increase was greater in the urea‐fed plants than those fed with NH₄NO₃. In both cultivars, addition of 50 μM Ni increased urease activity and thereby decreased the urea concentration in the urea treatment. Addition of 100 and 200 μM Ni caused a significant decrease in root and shoot growth of cucumber although this decrease was insignificant for cv. Super Dominus in the 100 μM treatment. The highest fruit yield, total soluble solids (TSS), and fruit firmness were achieved at the 50 μM Ni treatment. Regardless of nitrogen source, Ni addition proportional to the concentration used increased leaf Ni concentration and fruit acid ascorbic concentration. The concentration of Ni required for optimum growth and yield of cucumber varied with cultivars. The level of 50 μM was sufficient for optimum growth of cv. Negin in nutrient‐solution culture while lower concentration of Ni was required for cv. Super Dominus. While the beneficial effects of sufficient levels of Ni on growth and yield of urea‐fed plants was greater than with NH₄NO₃‐fed plants, the toxic effects of Ni in these plants were also greater.     

Applicability of support vector machines and adaptive neurofuzzy inference system for modeling potato crop evapotranspiration

Estimation of crop evapotranspiration (ET_C) for certain crops such as potato is very important for irrigation planning, irrigation scheduling and irrigation systems management. The primary focus of this study was to investigate the accuracy of the adaptive neurofuzzy inference system (ANFIS) and support vector machines (SVM) for potato ET_C estimation when lysimeter measurements or the complete weather data for applying the FAO method are not available. The estimates of the ANFIS and SVM models were compared with the empirical equations of Blaney–Criddle, Makkink, Turc, Priestley–Taylor, Hargreaves and Ritchie. The performances of the different SVM and ANFIS models were evaluated by comparing the corresponding values of root mean square error (RMSE), mean absolute error (MAE) and correlation coefficient (r). The drawn conclusions confirmed that the SVM and ANFIS models could provide more accurate ET_C estimates than the empirical equations. Overall, the minimum RMSE (0.042 mm/day) and MAE (0.031 mm/day) values and the maximum r value (0.98) were obtained using the SVM model with mean air temperature, relative humidity, solar radiation, sunshine hours and wind speed as inputs.     

Comparative analysis of 31 reference evapotranspiration methods under humid conditions

Evaluation of simple reference evapotranspiration (ET_o) methods has received considerable attention in developing countries where the weather data needed to estimate ET_o by the Penman–Monteith FAO 56 (PMF-56) model are often incomplete and/or not available. In this study, eight pan evaporation-based, seven temperature-based, four radiation-based and ten mass transfer-based methods were evaluated against the PMF-56 model in the humid climate of Iran, and the best and worst methods were selected from each group. In addition, two radiation-based methods for estimating ET_o were derived using air temperature and solar radiation data based on the PMF-56 model as a reference. Among pan evaporation-based and temperature-based methods, the Snyder and Blaney–Criddle methods yielded the best ET_o estimates. The ET_o values obtained from the radiation-based equations developed here were better than those estimated by existing radiation-based methods. The Romanenko equation was the best model in estimating ET_o among the mass transfer-based methods. Cross-comparison of the 31 tested methods showed that the five best methods as compared with the PMF-56 model were: the two radiation-based equations developed here, the temperature-based Blaney–Criddle and Hargreves-M4 equations and the Snyder pan evaporation-based equation.     

Effects of artemisinin in broiler chickens following chronic oral intake

Artemisinin has been used for centuries to treat malaria, intestinal tract helminthosis, diarrhea, and used as an antipyretic and sedative agent, but the usage in veterinary medicine is a new field. Recently, it has been used successfully to control experimental poultry coccidiosis. The present study aimed to determine the effects of different doses of artemisinin in broiler chickens with chronic usage. Sixty birds divided into one control and four treatment groups that fed rations mixed with artemisinin at doses of 17, 34, 68, and 136 ppm for 36 days. During the experiment, birds showed no clinical signs except anemia. In microscopic examinations, heart, lung, and spleen had no lesion, but liver, kidney, and brain showed various lesions. Degenerative lesions like intracytoplasmic eosinophilic inclusions were seen in both kidney and liver but fatty change was seen only in liver. There was no relationship between severity of the liver lesions and drug dosage. Central chromatolysis, scattered neuronal necrosis, and mild spongy changes were observed in five regions of the brain that were chosen for sectioning (motor cortex, cerebellar nuclei, midbrain nuclei, and hindbrain nuclei at two separate levels). Severity of lesions in brain was dose-dependent, and cerebral cortex was the most vulnerable area. Haematologic tests showed lower values for hematocrit and red blood cell count dose-dependently. In conclusion, artemisinin is a promising drug for prevention and control of coccidiosis in broiler chickens and its side effects are not too much serious especially at therapeutic doses.