Culture of Nile tilapia, Oreochromis niloticus (L.), at three stocking densities in outdoor concrete tanks using drainage water

Abstract. Effects of stocking density on water quality and on the growth, survival and food conversion of Oreochromis niloticus (Linnaeus) were evaluated. Fingerlings of tilapia (average weight 40.25 ± 94 g) were stocked in six 3.75-m³ concrete tanks at 16, 32 and 42.6/m³ and reared for 164 days. A water flow rate of 1 l/min/kg fish biomass was maintained in all the tanks. The growth rate was inversely related to stocking density with mean weights of 337.25g, 327.0g and 323.5g at the low, medium and high densities respectively. At harvest, standing crop biomass averaged 5.36 kg, 10.44kg and 13.24kg for the three densities. The respective food conversion ratios (FCR) were 1.85, 1.88 and 1.95, while the survival rates were 99.2, 99.6 and 95.9%. However, the survival rate, growth rate and food conversion efficiencies were not significantly different at the three stocking densities. Water quality did not deteriorate in different tanks as the oxygen was continuously replenished and metabolites and waste products removed by the water flowing through the tanks. These data suggest that culture of tilapia at a density of 42.6/m³ and production of 13.24 kg/m³ in 164 days with a production of 18–20 kg/m³ in a growing season (April-October) of 210 days is possible using the drainage water in flow-through water systems.     

From monsoons to mantas: seasonal distribution of Manta alfredi in the Maldives

The Republic of Maldives in the central Indian Ocean is home to large numbers of manta rays, Manta alfredi. They are known to undertake seasonal migrations within the Maldives, but these movements have not been well documented. The aims of this study were to map the seasonal distribution of manta rays within the Maldives, and to provide some indications of the physical and biological oceanographic processes affecting their distribution. The seasonal distribution of mantas was determined from a national survey of fishermen, interviews with experienced divers and personal observations. The data demonstrate that the distribution of mantas is strongly influenced by the seasonally reversing monsoon currents. Mantas occur on the downstream sides of the atolls, and are rare on the upstream sides, switching sides biannually as the monsoon currents change direction. These seasonally alternating currents are driven by monsoon winds which also alternate according to the season, and bring clear oceanic water to the upstream sides of the atolls. As the currents pass over the Maldives ridge, nutrient‐rich waters are lifted to the surface, promoting phytoplankton blooms (as demonstrated by the distribution of chlorophyll‐a) on the downstream sides of the atolls. This manifestation of the island mass effect supports an abundance of zooplankton, which in turn supports the manta rays.     

SAFETY AND CORRELATION OF TEST RESULTS OF COMBINED ULTRASOUND‐GUIDED FINE‐NEEDLE ASPIRATION AND NEEDLE CORE BIOPSY OF THE CANINE SPLEEN

The safety and diagnostic value of combined splenic fine‐needle aspiration (FNA) and needle core biopsy (NCB) is unknown. Forty‐one dogs with splenic lesions were studied prospectively. Safety was assessed in 38 dogs and no complications were encountered. Initially, clinical and anatomic pathologists reviewed each FNA and NCB sample, respectively, without knowledge of the other's results. Diagnoses were categorized as neoplastic, benign, inflammatory, normal, or nondiagnostic. The level of agreement between sampling methods was categorized as complete, partial, disagreement, or not available. Test correlation was performed in 40 dogs. Nondiagnostic results occurred in 5/40 NCB (12.5%) and no FNA samples. Neoplasia was diagnosed in 17/40 dogs (42.5%), benign changes in 20/40 dogs (50%), inflammatory disorders in 0/40 dogs, and normal 2/40 dogs (5%). One of the 40 dogs (2.5%) had a diagnosis that was equivocal for neoplasia on both tests and therefore was not categorized. Of the 35 dogs that had diagnostic samples, cytopathologic and histopathologic diagnoses agreed completely in 18/35 dogs (51.4%), partially in 3/35 dogs (8.6%), and were in disagreement in 14/35 dogs (40.0%). Pathologists collaboratively reviewed diagnoses that were in disagreement or partial agreement and altered their individual diagnoses in 6/17 dogs (35.3%) to be within partial or complete agreement, respectively. Percutaneous FNA and NCB can be performed safely in dogs with sonographic splenic changes. Results suggest that adding NCB to FNA provides complementary information in dogs with suspected splenic neoplasia. This combined protocol may improve detection of splenic neoplasia and provide neoplastic subclassification.     

Spread of Phoma exigua var. foveata to healthy potato plants

Contamination of stem-cutting bait plants exposed at various locations in and around a potato crop was greatest within the crop, less outside it and least at a site c. 20 km from commercial crops. Within the crop about half the stem infection and tuber contamination detected had occurred before haulm destruction. The incidence of contamination on tubers of bait plants placed within the crop was similar to that on tubers from the surrounding plants. Phoma exigua var. foveata was recovered from green leaves sampled at intervals between June and early September. In one year contamination by P. exigua var. foveata of tubers sampled from healthy plants surrounding a diseased plot was greatest in samples adjacent to the plot and decreased progressively away from it. This pattern was less apparent in two other years. These results are discussed in relation to the spread of airborne inoculum.     

IMAGING DIAGNOSIS—VERTEBRAL CANAL PORCUPINE QUILL WITH PRESUMPTIVE SECONDARY ARACHNOID DIVERTICULUM

A 3‐year‐old Gordon Setter developed cervical hyperesthesia and a stiff gait. Upon magnetic resonance (MR) imaging, an arachnoid diverticulum was detected at the C1 level. Upon surgical resection, a porcupine quill was identified within the vertebral canal in the area of the cyst. At a retrospective review of the MR images, the quill appeared as a circular well‐demarcated T2‐hypointense lesion. Porcupine quill migrations are common in the dog but migration into the central nervous system is rare.     

Evaluation of a Collagenase Generated Osteoarthritis Biomarker in the Synovial Fluid from Elbow Joints of Dogs with Medial Coronoid Disease and Unaffected Dogs

Objective— To evaluate whether synovial fluid concentrations of an osteoarthritis biomarker in dysplastic canine elbows with medial coronoid disease (MCD) are elevated compared with unaffected elbows and to determine if these concentrations correlate to the degree of articular cartilage damage.
Study Design— Cross sectional clinical study.
Animals— Dogs (n=19; 35 elbows) with MCD and dogs (8; 16 elbows) with unaffected elbows.
Methods— Concentrations of a collagenase-generated cleavage neoepitope of type II collagen (Col2-3/4C_{long mono}, or C2C) in joint fluid from elbows were analyzed and compared between dogs with MCD and unaffected dogs. Correlation of C2C concentration with subjective grading of articular cartilage surface damage was also evaluated.
Results— Mean (±SD) C2C concentration from MCD dogs was significantly higher (112.3±24.8 ng/mL) than in unaffected dogs (76.1±16.9 ng/mL; P <.05). There was a moderate correlation between cartilage damage grade and increasing C2C concentrations ( P <.05, r=0.62)
Conclusion— C2C concentrations are elevated in the synovial fluid of dogs with MCD compared with unaffected elbows, and a moderate, significant correlation was identified between these concentrations and subjective grading of articular cartilage damage.
Clinical Relevance— This preliminary data suggest that C2C concentrations in synovial fluid may have potential as a biomarker for diagnosis of articular cartilage damage associated with MCD and as a means of objectively determining the degree of articular cartilage damage.     

Stable reversal of multidrug resistance of colon cancer cells by RNAi targeting MDR1 gene

AIM: To investigate the reversal effect of RNAi targeting MDR1 gene on MDR1/P-gp-dependent multidrug resistance of colon cancer cells. METHODS: Plasmid vectors pSilencer-#4029 encoding #4029 MDR1 siRNA and pSilencer-#4123 encoding #4123 MDR1 siRNA were constructed, respectively. Plasmid vectors were transfected into COLO 320DM cell line, a colon cancer multidrug resistance cell line. Clone cells were screened by G418 and identified by real time RT-PCR and Western blotting. Cell viabilities were measured by MTT assay. Cell cycle analysis was performed with flow cytometry. Intracellular adriamycin accumulations were measured by flow cytometry. RESULTS: The expression of MDR1 mRNA and P-gp in positive clone cells (clone #4029 and clone #4123) were all inhibited. IC50 of adriamycin and vincristine for COLO 320DM parent cells were 9.616 μmol/L and 0.358 μmol/L, respectively. However, for clone #4029, they were decreased to 1.094 μmol/L and 0.023 μmol/L, respectively (P<0.01). For clone #4123, they were decreased to 0.780 μmol/L and 0.035 μmol/L, respectively (P<0.01). The PI/AI values of COLO 320DM parent cells treated with adriamycin and vincristine were 5.68 and 9.59, respectively. However, they were decreased to 2.74 and 3.59 respectively for clone #4029 (P<0.01). They also decreased to 2.75 and 3.24 respectively for clone #4123 (P<0.01). The intracellular adriamycin accumulation concentrations of COLO 320DM parent cells treated with 10 μmol/L adriamycin were 27.92. However, they were increased to 187.24 and 215.57 for clone #4029 and clone #4123, respectively (P<0.01). CONCLUSION: Stable transfection of plasmid vector encoding MDR1 siRNA stably reverses MDR1/P-gp-dependent multidrug resistance of colon cancer cells.     

The efficacy of berenil (diminazene aceturate) against Trypanosoma evansi infection in mice

The efficacy of berenil (diminazene aceturate) was studied in experimental Trypanosoma evansi infection in albino mice. The criteria used for the assessment of the anti-trypanosomal effect of berenil included the examination of the blood and tissues for T. evansi and the clinical, pathological and enzyme histochemical changes seen in the lungs, heart, liver, kidney and spleen at intervals after treatment. Single doses of 10 and 20 mg/kg of berenil given intraperitoneally or intramuscularly to infected mice produced a complete elimination of the protozoon and caused a slow tissue recovery mirrored in the persistence of lesions in different organs. Single doses of 3.5 mg/kg of berenil were less effective and none of the three dose levels of the drug used induced toxic effects in albino mice.