Demonstration of the agent of bovine viral diarrhea-mucosal disease (BVD/MD) in comparison between organ fluoresence freezing method and the direct cultivation in tissue culture]

Organs of 100 calves whose clinical symptoms indicated a BVD/MD viral infection have been examined in the laboratory by different methods on BVD/MD virus in order to compare the effectivity of the single test-systems. By inoculation of organ material into tissue culture from foetal calf kidneys and additional staining with swine-fever conjugate in the CCSC-system 59 calves were detected as BVD/MD virus carriers. Taking this result for comparative purposes equal to 100% there could be stated an effectivity of 73% by inoculation of tissue cultures and judging cpe instead of staining with fluorescent antibody as above. Only 34% reactions could be demonstrated by means of heterotypic immunofluorescence in organ tissues. For diagnostic purposes a combination of the easy and quick method of heterotypic immunofluorescence in organ tissues and a cultural virus isolation from organ material with additional immunofluorescence is recommended.     

Quantifying moisture and roughness with Support Vector Machines improves spectroscopic soil organic carbon prediction

The challenges of Vis‐NIR spectroscopy are permanent soil surface variations of moisture and roughness. Both disturbance factors reduce the prediction accuracy of soil organic carbon (SOC) significantly. For improved SOC prediction, both disturbance effects have to be determined from Vis‐NIR spectra, which is especially challenging for roughness. Thus, an approach for roughness quantification under varying moisture and its impact on SOC assessment using Support Vector Machines is presented here.     

The Effect of Ammonia,Nitrite, and Nitrate on the Oxygen Consumption of Juvenile Pink Shrimp Farfantepenaeus brasiliensis (Latreille, 1817) (Crustacea: Decapoda)

The pink shrimp Farfantepenaeus brasiliensis is native in southern Brazil and is potentially suited for aquaculture. Under intensive culture, the accumulation of nitrogenous compounds results from excretion by the shrimp and from the processes of feed decomposition and nitrification. The objective of this study was to evaluate ammonia, nitrite, and nitrate toxicity effects on oxygen consumption of juvenile pink shrimp. Shrimps (initial weight 0.7 ± 0.15 g) were exposed over a period of 30 days to 50%, 100%, and 200% of the safe levels of total ammonia (TAN = 0.88 mg/L), nitrite (NO₂^? = 10.59 mg/L), and nitrate (NO₃^? = 91.20 mg/L) for the species. The specimens were individually collected and placed in respirometry chambers, where the oxygen consumption was measured over a period of two hours. Throughout the experiment there was no significant difference (p > 0.05) among treatments in terms of survival and growth. The pink shrimp juveniles exposed to nitrogen concentrations of 200% of the nitrite and nitrate safe level showed the highest oxygen consumption (p < 0.05).     

Application of different doses of calcium hydroxide in the farming shrimp Litopenaeus vannamei with the biofloc technology (BFT)

The reduction in alkalinity and pH occurs due to the consumption of inorganic carbon by bacteria present in the biofloc. The objective of the study was to evaluate the effects of different doses of calcium hydroxide on the water quality and growth performance of the Litopenaeus vannamei in a biofloc system. The experiment consisted of four treatments with three repetitions for each treatment: Control treatment (TC), in which the pH maintained above 7.2 due to the application of 0.05 g L^?1 of calcium hydroxide, and treatments T10, T20 and T40, in which daily doses of calcium hydroxide equivalent to 10, 20 and 40 % of the total amount of feed offered to the shrimp, respectively, were added to the environment. Twelve experimental units (150 L) were stocked with 85 juveniles of L. vannamei (0.18 ± 0.06 g), corresponding to a density of 425 shrimp m^?3, and cultivated for 56 days. The values of alkalinity and pH for treatments TC and T10 were similar and significantly lower (p < 0.05) than those for treatments T20 and T40, which differed (p < 0.05) between each other. In terms of growth performance, TC, T10 and T20 performed significantly better (p < 0.05) than T40. There were no significant differences (p > 0.05) in the survival rates. The results obtained indicate that doses of 0.05 g L^?1 of calcium hydroxide or daily applications between 10 and 20 % of the total amount of feed offered to the shrimp can be used for the correction of alkalinity and pH.     

Another dolphin in peril? Photo‐identification,occurrence, and distribution of the endangered Indian Ocean humpback dolphin (Sousa plumbea) in Algoa Bay

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The effect of different alkalinity levels on <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis> reared with biofloc technology (BFT)

The initial stages of rearing marine shrimp using biofloc technology (BFT) involve the biofloc formation process. At the same time, there is an increase in the levels of total suspended solids and a decrease in alkalinity and pH. This reduction of alkalinity and pH occurs due to the consumption of inorganic carbon by the autotrophic bacteria present in the bioflocs and biofilms. The aim of this study was to evaluate the effects of different alkalinities on water quality and the zootechnical performance of the marine shrimp Litopenaeus vannamei in a BFT system. The experiment consisted of four treatments, with three replicates each: 75, 150, 225 and 300 mg CaCO₃/L. To maintain the alkalinity at the established level, sodium bicarbonate was applied. For the experiments, twelve experimental units (area = 0.20 m²) with an effective volume of 50 L were stocked with 30 juvenile L. vannamei (0.20 ± 0.07 g), to achieve a stocking density of 150 shrimps/m² and were maintained for an experimental period of 49 days. The 75 treatment presented the highest levels of ammonia and nitrite throughout the study, compared to the 150 and 300 treatments. The results showed that higher alkalinity favors biofloc formation and the establishment of nitrifying bacteria.