Respiration of adult female Calanus hyperboreus (Copepoda) during spring in the North Water Polynya

The respiration rate of adult female Calanus hyperboreus was determined in order to assess physiological activity and its relationship to food availability during spring in the North Water Polynya, northern Baffin Bay. The respiration rate increased hyperbolically with increasing ambient chlorophyll α (Chl. α) concentration regardless of the reproductive status. The increase of respiration with Chl. α concentration may be caused by activated feeding behavior. This suggests that all adult females during spring were physiologically active individuals. Possible advantages of the rapid response to food concentration in adult female copepods are discussed

Lumostatic operation controlled by the optimum light intensity per dry weight for the effective production of Chlorella zofingiensis in the high cell density continuous culture

To maximize the production rate of Chlorella zofingiensis, a lumostatic continuous culture was operated under light intensities of 250–1510 μE m− 2 s− 1. The cell density and volumetric biomass production rate were increased without photo inhibition and reached 13.5 g-dry weight (dw) L− 1 on day 21.5 and 2.41 g-dw L− 1 day− 1 on day 10.5, respectively. These maximum values were higher than any previous photoautotrophic culture study with C. zofingiensis. The specific growth rate was maintained at a high level > 0.5 day− 1 until the light intensity per dry weight decreased below 28 μE g-dw− 1 s− 1, which coincided with the value estimated in our previous study, verifying the reliability of this estimated value. There was a strong relationship between the photosynthetic efficiency and light intensity per dry weight for C. zofingiensis. This relationship may be useful for evaluating species-specific productivity to select productive species

Release of nitrogen and phosphorus from aquaculture farms to Selangor River, Malaysia

The release of nitrogen and phosphorus from aquaculture ponds to Selangor River, Malaysia was estimated. The concentrations of nitrogen and phosphorus in aquaculture ponds were always higher than those in the river, their primary water source, indicating that the aquaculture ponds are sources of nitrogen and phosphorus in Selangor River. From the careful interview with aquaculture managers, the frequency of water exchange, the number of harvesting, and the amount of feeds added, the total volume of water released to the Selangor River was also obtained. The total amount of nitrogen and phosphorus added to each aquaculture pond was estimated to be about 700 kg N and 60 kg P per year, respectively. About 100-200 kg N and 10-15 kg P were estimated to be released with the waste water per pond per year, accounting for 20-30% of nitrogen and phosphorus in added feeds. It is important for us to precisely estimate the fates of nutrients for the better management and sustainable development of aquaculture industries. Our data may help to improve aquaculture management in future

Phenolic content and antioxidant activity of Tetraselmis tetrathele (West) Butcher 1959 cultured in annular photobireactor

Tetraselmis tetrathele (West) Butcher is an important microalgae due to its high antioxidant content and other bioactive compounds such as flavonoids and polyphenols. Therefore, it has potential as a suitable raw ingredient for various product developments in aquaculture, food and nutraceutical industries. The antioxidant activity of T. tetrathele (UPMC-A0007) was determined by culturing in f/2 and Conway media for 56 days in 120 l annular photobioreactors. The total phenolic (TPC) and antioxidant contents of T. tetrathele were determined six times during different phases of the culture period. The antioxidant activities of T. tetrathele's crude extract were determined by diphenylpicrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays. Two groups of cells based on size; small sized-cells (3.0-5.0?10-11g cell(-1)) and big sized-cells (5.5-8.0?10(-11) g cell(-1)) were observed in the f/2 media. Small sized-group showed 1.6 times higher total phenolic content (2.99?0.14 mg GAEg(-1)) than big sized-cells. These results suggest that T. tetrathele is a potential antioxidant source and effective antioxidant production can be achieved by controlling the cell size in their culturing process

Multiplex Polymerase Chain Reaction Assay for Early Diagnosis of Viral Infection

Viral reactivation is one of the most serious complications for immunocompromised patients. Under immunosuppressive conditions, some viruses can be reactivated solely or simultaneously and may thus cause life-threatening infection. Therefore, the prompt and proper diagnosis of viral reactivation is important for the initiation of preemptive therapy. For this purpose, we recently developed a multiplex-virus polymerase chain reaction (PCR) assay. The multiplex PCR assay is designed to qualitatively measure the genomic DNA of 12 viruses at once: cytomegalovirus (CMV), human herpesvirus type 6 (HHV-6), HHV-7, HHV-8, Epstein-Barr virus (EBV), varicella-zoster virus (VZV), BK virus (BKV), JC virus (JCV), parvovirus B19 (ParvoB19), herpes simplex virus type 1 (HSV-1), HSV-2, and hepatitis B virus (HBV). When a specific PCR signal is obtained, the viral load is determined by a quantitative real-time PCR. The qualitative multiplex and quantitative real-time PCR procedures take only 3 hours to complete. With this assay system, we can identify viremia at the early stage and thereby prevent it from progressing to overt and symptomatic viral infection in immunocompromised patients, such as those receiving hematopoietic stem cell transplantation

Effect of temperature on thermophilic composting of aquaculture sludge: NH3 recovery, nitrogen mass balance, and microbial community dynamics

Development of thermophilic composting for maximizing NH3 gas recovery would enable the production of a nitrogen source which is free from pathogen/heavy metal, for the cultivation of high-value microalgae. The present study examined the effect of NH3 recovery, nitrogen mass balance, and microbial community dynamics on thermophilic composting of shrimp aquaculture sludge. The emission of NH3 gas at 60 and 70 °C was 14.7% and 15.6%, respectively, which was higher than that at 50 °C (9.0%). The nitrogen mass balance analysis revealed that higher temperatures enhanced the solubilization of non-dissolved nitrogen and liberation of NH3 gas from the produced NH4+-N. High-throughput microbial community analysis revealed the shift of the dominant bacterial group from Bacillus to Geobacillus with the rise of composting temperature. In conclusion, thermophilic composting of shrimp aquaculture sludge at 60–70 °C was the most favorable condition for enhancing NH3 gas recovery

Estimation of optimum specific light intensity per cell on a high-cell-density continuous culture of Chlorella zofingiensis not limited by nutrients or CO2

To determine the optimum light intensity per cell required for rapid growth regardless of cell density, continuous cultures of the microalga Chlorella zofingiensis were grown with a sufficient supply of nutrients and CO2 and were subjected to different light intensities in the range of 75–1000 μE m−2 s−1. The cell density of culture increased over time for all light conditions except for the early stage of the high light condition of 1000 μE m−2 s−1. The light intensity per cell required for the high specific growth rate of 0.5 day−1 was determined to be 28–45 μE g-ds−1 s−1. The specific growth rate was significantly correlated to light intensity (y = 0.721 × x/(66.98 + x), r2 = 0.85, p < 0.05). A high specific growth rate was maintained over a range of light intensities (250–1000 μE m−2 s−1). This range of light intensities suggested that effective production of C. zofingiensis can be maintained outdoors under strong light by using the optimum specific light intensity

Dietary supplementation of astaxanthin enhances hemato-biochemistry and innate immunity of Asian seabass, Lates calcarifer (Bloch, 1790)

This study aimed to evaluate the impacts of dietary astaxanthin supplementation on hematology, blood biochemistry and innate immunity of Asian seabass Lates calcarifer, with special reference to dose-response associations and variations over different phases of feeding (short-term, medium-term and long-term). Triplicate groups of fish (n = 30) with an average weight of 28 g were fed astaxanthin-incorporated diets (AX50, 50 mg kg−1 diet; AX100, 100 mg kg−1 diet; AX150, 150 mg kg−1 diet) for 90 days. A diet without astaxanthin supplement (CD) served as the control. Our findings demonstrated that fish displayed significant enhancements (P < .05) in hematological indices (white blood cell count, red blood cell count, hemoglobin and hematocrit) when fed various diets with elevated doses of astaxanthin throughout the specified phases of feeding. Serum concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), glucose, and cortisol in fish fed the supplemented diets decreased significantly (P < .05) with increasing dietary inclusion levels. Moreover, the provision of dietary astaxanthin at escalating doses markedly reduced (P < .05) the circulating levels of serum cholesterol (proportionately) and triglyceride (dose-dependently) in fish, following three consecutive feeding phases. Correspondingly, the supplemented fish exhibited much higher (P < .05) serum total protein content associated with astaxanthin administration. Immunological parameters (respiratory burst activity, lysozyme activity, phagocytic activity, and serum total immunoglobulin) of fish were significantly stimulated (P < .05) in response to dietary intervention with astaxanthin. The present investigation highlights the ameliorating effect of dietary astaxanthin on hemato-biochemical and immunological variables of Asian seabass and could be administered in culture protocols to improve fish immunocompetence and health

Seasonal changes of nutrient distributions along Selangor River, Malaysia

Water samples were taken six times along Selangor River between January 2014 and May 2015 in order to estimate the nutrient changes in different seasons. In the upstream, the nutrient concentrations were higher during the wet period compared to the dry due to the nutrient loading from the eroded soils. Aquaculture ponds could also contribute to the nutrient elevation. Nearly 10 % of the increased nutrients between two sampling stations could come from the aquaculture waste. The relatively high ammonia concentrations were observed in the lower part of Selangor River due to a significant input of ex-mining ponds water and one major arm river which flows through large towns. Our results showed the water quality of Selangor River is clean enough to be suitable for drinking water, but the further study of other parameters such as heavy metals is necessary to ensure the water quality of Selangor River