Effect of enriching live feeds with HUFA on growth and survival of clownfish Amphiprion ocellaris (Cuvier, 1830) larvae

The aims of this study was to evaluate the effect of HUFA-enriched live feed in rearing Nemo fish larvae (Amphiprion ocellaris), 5 treatments were set up (each treatment was repeated in triplicate) with 5 concentrations of HUFA (Super Selco) (0, 50, 100, 150 and 200 ppm). After 45 days of culture with HUFA-enriched live feeds of different concentrations, the total length-TL as well as the specific growth rate (SGRL) in body length and survival rate of Nemo fish larvae in the treatments had significant differences (p 0.05). In the enriched live prey diet of 100 ppm Selco, TL, SGRL and the survival rate of Nemo fish larvae were the highest (10.01 ± 0.150 mm, 7.20 ± 0.099%/day and 82.67 ± 0.881%, respectively). Lowest TL, SGRL and survival rate were obtained in larvae fed with the control diet (8.65 ± 0.051 mm, 6.23 ± 0.041%/day and 68.70 ± 0.881%, respectively). The results of this experiment suggest that the optimal Selco concentration used to enrich live feeds for Nemo fish larvae is 100 ppm, which can improve the production efficiency of Nemo stock

Effects of dietary Mannan oligosaccharide (MOS) on grown, survival rate, intestinal morphology and blood cell count of the golden trevally fish (Gnathanodon specious)

The golden trevally fishes (Gnathanodon specious) (2.19 ± 0.23 g) were cultured in glass tanks with density of 20 fishes/tank and they were fed supplemental diets of different MOS concentrations (0; 0.2; 0.4 and 0.6%) for 90 days. Collected data included growth rate, survival rate and some hematological characteristics of this fish. The results demonstrated that MOS supplementation did not affect growth performance, erythrocyte density and blood cell size, however the survival rate was significantly increased. On the other hand, the total number of white blood cells (BC) on the 60th day in the fish fed with MOS supplements (5.78–6.96 × 104TB/mm3) was higher than that in the control group (only 5.43 × 104TB/mm3) with the largest total leukocytes (6.96 ± 0.50 × 104TB /mm3) at 0.2% MOS (p 0.05)

ẢNH HƯỞNG CỦA NỀN ĐÁY CÁT VÀ ĐÁ SỐNG LÊN CHẤT LƯỢNG MÔI TRƯỜNG BỂ NUÔI CÁ CẢNH BIỂN

Marine ornamental aquarium is more and more popular. Nowadays, biofiltration system can convert nitrogen from toxic forms (NH4+/NH3, NO2-) into a less toxic form (NO3-), which creates a better water quality for the development of ornamental fishes in aquarium tank. This experiment was carried out to evaluate the efficiency of environmental quality by supplementation of sand and live rock in aquarium tank. There were two treatments with rock and sand supplement to the bottom of the tanks (NT1) and tanks without rock and sand added (NT2). There were 3 replicates for each treatment and the experiments were carried out in ten weeks. Results showed that sand and live rock could improve water quality and play as good place for fish and other creature hiding and reduce the water used. Water temperatures were 28.69oC (NT1) and 28.80oC (NT2), pH was about 8.13, salinity ranged from 34‰ to 35‰ in both treatments. NH4+was 0.035 ± 0.003 mgN/ml in the two treatments. After 2 weeks of putting fish in the experimental tanks NO2- values were 0.023 mgN/l (in treatment NT2) and 0.018 mgN/l (in treatment NT1). The average values of NO2- for whole experimental period in the NT1 and NT2 were 0.008 ± 0.001 mgN/l and 0.010 ± 0.002 mgN/l, respectively (P = 0.061). NO3- values were not significantly different between the two treatments (P 0.05). However, the ratio of NO2-/NO3- in NT1 was lower compared to this value in NT2 (NT1: 0.15 ± 0.03% and NT2: 0.39 ± 0.09%, P = 0.018). This paper provides an important reference to help aquarists to design and control their ornamental aquarium tank suitably.Hệ thống lọc sinh học là nơi sinh sống của các vi khuẩn ni trat hóa - các vi khuẩn có vai trò chuyển hóa ni tơ thải ra từ cá và vật nuôi ở dạng độc (NH4+/NH3) sang dạng ít độc hơn (NO3-). Các vi khuẩn này sống bám trên các giá thể như đá và cát. Thí nghiệm đánh giá hiệu quả cải thiện chất lượng môi trường của việc bổ sung nền đáy cát và đá vào bể nuôi cá cảnh biển. Thí nghiệm bao gồm 2 nghiệm thức. Nghiệm thức 1 (NT1): Bổ sung đá sống và cát vào bể nuôi và nghiệm thức 2 (NT2): Bể nuôi có đáy trần. Mỗi nghiệm thức có kết quả thí nghiệm cho thấy, bổ sung nền đáy cát và đá sống vào bể nuôi đã đem lại hiệu quả cải thiện rõ rệt các muối dinh dưỡng nitơ từ dạng có độc hại cho vật nuôi sang dạng ít độc hơn. Nhiệt độ 28,69oC (NT1) và 28,80oC (NT2), pH xấp xỉ 8,13 và độ mặn dao động 34–35‰ ở cả 2 nghiệm thức thí nghiệm. NH4+ở cả 2 nghiệm thức có giá trị trung bình 0,035 ± 0,003 mgN/ml. Sau 2 tuần thả cá, hàm lượng NO2- 0,023 mgN/l (NT2) và 0,018 mgN/l (NT1). NO2- trung bình ở NT1 và NT2 lần lượt là 0,008 ± 0,001 mgN/l và 0,010 ± 0,002 mgN/l (P = 0,061). Hàm lượng NO3- giữa 2 nghiệm thức không khác nhau có ý nghĩa thống kê (P 0,05). Tuy nhiên, tỷ lệ NO2-/NO3- ở NT1 nhỏ hơn có ý nghĩa thống kê so với NT2 (NT1: 0,15% ± 0,03% và NT2: 0,39% ± 0,09%, P = 0,018). Ngoài ra việc bổ sung nền đáy cát và đá sống tạo sinh cảnh và tạo nơi ẩn nấp cho cá. Đồng thời cũng giúp hạn chế thay nước và vệ sinh nền đáy của bể nuôi có đáy cát và đá sống. Kết quả nghiên cứu là cở sở khoa học quan trọng để bổ sung đá sống và cát trong bể nuôi cá cảnh tại Bảo tàng Hải dương học

Comparative Susceptibility of Aedes albopictus and Aedes aegypti to Dengue Virus Infection After Feeding on Blood of Viremic Humans: Implications for Public Health.

Aedes albopictus is secondary to Aedes aegypti as a vector of dengue viruses (DENVs) in settings of endemicity, but it plays an important role in areas of dengue emergence. This study compared the susceptibility of these 2 species to DENV infection by performing 232 direct blood-feeding experiments on 118 viremic patients with dengue in Vietnam. Field-derived A. albopictus acquired DENV infections as readily as A. aegypti after blood feeding. Once infected, A. albopictus permitted higher concentrations of DENV RNA to accumulate in abdominal tissues, compared with A. aegypti. However, the odds of A. albopictus having infectious saliva were lower than the odds observed for A. aegypti (odds ratio, 0.70; 95% confidence interval, .52-.93). These results quantitate the susceptibility of A. albopictus to DENV infection and will assist parameterization of models for predicting disease risk in settings where A. albopictus is present

ẢNH HƯỞNG CỦA VITAMIN E BỔ SUNG VÀO THỨC ĂN ĐẾN HIỆU QUẢ SINH SẢN, CHẤT LƯỢNG TRỨNG VÀ ẤU TRÙNG CÁ KHOANG CỔ NEMO (Amphiprion ocellaris (CUVIER, 1830))

This study was carried out to determine the effects of vitamin E (a-tocopherol) in five levels (0, 125, 250, 375 and 500 mg vitamin E/kg feed) in broodfish diets on reproductive, egg and larval quality parameters of clownfish (Amphirion ocellaris). Each treatment was repeated in triplicate and the supplemental feeding trial was arranged for 13 months. The result showed that there were no significant differences in re-maturation and spawning periods, spawning frequency, fecundity, egg diameter and larval size of Nemo fish observed between the treatments. However, diets supplemented with vitamin E positively influenced the rate of egg loss, hatching rate of egg and survival rate of the 3 days post hatch. The overall result of this experiment indicated that the optimum vitamin E requirement of clownfish for reproductive performance was 375 mg vitamin E/kg feed.Thí nghiệm được thực hiện nhằm xác định ảnh hưởng của vitamin E (0, 125, 250, 375 và 500 mg/kg thức ăn) được bổ sung trong thức ăn cá bố mẹ đến các chỉ số sinh sản, chất lượng trứng và ấu trùng cá khoang cổ Nemo (Amphiprion ocellaris). Mỗi nghiệm thức được lặp lại 3 lần và thí nghiệm được tiến hành trong 13 tháng. Kết quả đã cho thấy thời gian tái thành thục và sinh sản, tần suất sinh sản, sức sinh sản thực tế, đường kính trứng và kích thước ấu trùng không bị ảnh hưởng bởi chế độ ăn bổ sung vitamin E ở các mức khác nhau. Tuy nhiên, chế độ ăn có bổ sung vitamin E đã ảnh hưởng tích cực đến tỷ lệ hao hụt của trứng, tỷ lệ trứng nở và tỷ lệ sống của ấu trùng 3 ngày tuổi. Kết quả nghiên cứu chỉ ra rằng nhu cầu vitamin E tối ưu của cá khoang cổ Nemo đạt được hiệu quả sinh sản là 375 mg vitamin E/kg thức ăn

Genome evolution of dengue virus serotype 1 under selection by <i>Wolbachia pipientis</i> in <i>Aedes aegypti</i> mosquitoes.

The introgression of antiviral strains of Wolbachia into Aedes aegypti mosquito populations is a public health intervention for the control of dengue. Plausibly, dengue virus (DENV) could evolve to bypass the antiviral effects of Wolbachia and undermine this approach. Here, we established a serial-passage system to investigate the evolution of DENV in Ae. aegypti mosquitoes infected with the wMel strain of Wolbachia. Using this system, we report on virus genetic outcomes after twenty passages of serotype 1 of DENV (DENV-1). An amino acid substitution, E203K, in the DENV-1 envelope protein was more frequently detected in the consensus sequence of virus populations passaged in wMel-infected Ae. aegypti than wild-type counterparts. Positive selection at residue 203 was reproducible; it occurred in passaged virus populations from independent DENV-1-infected patients and also in a second, independent experimental system. In wild-type mosquitoes and human cells, the 203K variant was rapidly replaced by the progenitor sequence. These findings provide proof of concept that wMel-associated selection of virus populations can occur in experimental conditions. Field-based studies are needed to explore whether wMel imparts selective pressure on DENV evolution in locations where wMel is established

A modified Sequential Organ Failure Assessment score for dengue: development, evaluation and proposal for use in clinical trials

Background Dengue is a neglected tropical disease, for which no therapeutic agents have shown clinical efficacy to date. Clinical trials have used strikingly variable clinical endpoints, which hampers reproducibility and comparability of findings. We investigated a delta modified Sequential Organ Failure Assessment (delta mSOFA) score as a uniform composite clinical endpoint for use in clinical trials investigating therapeutics for moderate and severe dengue. Methods We developed a modified SOFA score for dengue, measured and evaluated its performance at baseline and 48 h after enrolment in a prospective observational cohort of 124 adults admitted to a tertiary referral hospital in Vietnam with dengue shock. The modified SOFA score included pulse pressure in the cardiovascular component. Binary logistic regression, cox proportional hazard and linear regression models were used to estimate association between mSOFA, delta mSOFA and clinical outcomes. Results The analysis included 124 adults with dengue shock. 29 (23.4%) patients required ICU admission for organ support or due to persistent haemodynamic instability: 9/124 (7.3%) required mechanical ventilation, 8/124 (6.5%) required vasopressors, 6/124 (4.8%) required haemofiltration and 5/124 (4.0%) patients died. In univariate analyses, higher baseline and delta (48 h) mSOFA score for dengue were associated with admission to ICU, requirement for organ support and mortality, duration of ICU and hospital admission and IV fluid use. Conclusions The baseline and delta mSOFA scores for dengue performed well to discriminate patients with dengue shock by clinical outcomes, including duration of ICU and hospital admission, requirement for organ support and death. We plan to use delta mSOFA as the primary endpoint in an upcoming host-directed therapeutic trial and investigate the performance of this score in other phenotypes of severe dengue in adults and children

Effects of Dietary Mannan Oligosaccharides on Growth, Nonspecific Immunity and Tolerance to Salinity Stress and Streptococcus iniae Challenge in Golden Pompano, Trachinotus ovatus

The effects of dietary supplementation with mannan oligosaccharide (MOS) on growth performance, haematological parameters, abundance of intestinal Vibrio spp., immune response, and tolerance to low salinity stress and Streptococcus iniae challenge were evaluated in pompano (Trachinotus ovatus). Pompano (3.24 ± 0.45 g) were fed six diets including a basal diet as control, and the basal diets supplemented with 0.1%, 0.2%, 0.4%, 0.6%, or 0.8% MOSs for 8 weeks. The results showed that pompano fed 0.1%–0.4% MOS had significantly improved specific growth rates (P≤0.039). Dietary MOS did not affect the survival rate of pompano (P=0.192). WBC count was significantly higher in fish fed diets containing 0.1%–0.6% MOS. Dietary MOS increased lymphocytes count (P≤0.042) and reduced monocytes and basophils counts (P≤0.019); however, no effects were found on neutrophils and eosinophil numbers (P≥0.064). Intestinal Vibrio spp. counts reduced in fish fed diets containing 0.1%–0.4% MOS (P≤0.035). The phagocytic ratio significantly increased in pompano fed diets containing 0.1%–0.6% MOS (P≤0.015), while the phagocytic index and serum lysozyme activity in fish fed 0.1%–0.4% MOS were significantly higher than the control (P≤0.035). There were significant positive correlations between MOS levels and fish growth on days 14, 28, 42, and 56 (P≤0.049). In addition, dietary MOS levels were highly correlated with blood parameters, abundance of intestinal Vibrio spp., and immune responses. Optimal dietary MOS requirements for maximal growth were estimated to be 0.440% on day 21 (R2 = 0.861), 0.385% on day 28 (R2 = 0.877), 0.371% on day 42 (R2 = 0.891), and 0.365% on day 56 (R2 = 0.750), showing decreasing tendency in MOS requirement as fish size increased. Furthermore, the optimal MOS concentration for maximal immunity based on lysozyme activity was estimated to be 0.431% (R2 = 0.817) on day 56. In addition, fish fed 0.1%–0.4% MOS showed better resistance to low salinity stress and Streptococcus iniae challenges (P≤0.014). In conclusion, MOS supplementation effectively reduced the prevalence of intestinal Vibrio spp. and enhanced the growth, immune responses, and tolerance to low salinity stress and Streptococcus iniae in juvenile pompano

Green synthesis of silver nanoparticles using <i>Mentha crispa</i> L. leaf extract for treatment of dye wastewater

Mentha crispa L. is one of Vietnam’s most precious folk medicines and is also a spice used in many delicious dishes in Vietnam and around the world. The use of Mentha crispa L. leaf extract as a reducing agent for Ag+ ions to synthesize silver nanoparticles is discussed in this paper. Single silver nanospheres were dispersed in biological media and their sizes were controlled in the range of 20-80 nm. Factors affecting particle size and shape such as extract concentration, AgNO3 concentration, reaction time, and temperature were investigated to determine the optimal parameters for particle synthesis. The optical properties, dispersion, crystal structure, morphology, and sizes of silver nanoparticles were investigated through UV-Vis absorption spectroscopy, dynamic light scattering (DLS) measurements, X-ray diffraction, and transmission electron microscopy (TEM). The functional groups on the L.AgNPs were determined by Fourier-transform infrared (FTIR) transmittance spectra. The synthesised silver nanoparticles were used to treat methylene blue (MB) dye, the main component of dye wastewater, based on their photocatalytic properties. The results show that in the presence of L.AgNPs, the photodegradation efficiency of NaBH4 or H2O2 reducing agents is much higher, up to 95% of illumination