In zebrafish, ovulated oocytes contain both maternal cortisol and the mRNA for the glucocorticoid receptor (gr), which is spread as granular structures throughout the ooplasm. At 0.2 hpf, this transcript is relocated in the blastodisc area and partitioned among blastomeres. At 6-8 hpf, it is replaced by zygotic transcript. We used morpholinos to block translation of both maternal and zygotic gr transcripts, and a missplicing morpholino to block post-transcriptionally the zygotic transcript alone. Only knockdown of translation produced an increase of apoptosis and subsequent craniofacial and caudal deformities with severe malformations of neural, vascular, and visceral organs in embryos and 5-dpf larvae. Such defects were rescued with trout gr2 mRNA. Microarray analysis revealed that 114 and 37 highly expressed transcripts were up-and down-regulated, respectively, by maternal Gr protein deficiency in 5-hpf embryos. These results indicate that the maternal gr transcript and protein participate in the maternal programming of zebrafish development. Developmental Dynamics 240:874-889,

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Antimicrobials are commonly used to prevent and treat disease in the ornamental fish industry. However, the indiscriminate and comprehensive overuse of unregulated antimicrobials without appropriate diagnostic examination could contribute to the development of antimicrobial-resistant strains of bacterial pathogens. Moreover, human infections caused by pathogens transmitted from fish or the aquatic environment are quite common. The frequent detection of antimicrobial resistance in ornamental fish and their environments are inevitable so as to decrease the transfer of antimicrobial-resistant bacteria from aquatic sources to other environments. This study evaluated the prevalence of common bacteria species and the antimicrobial susceptibility profile in ornamental fish that were sold in an ornamental fish shop in Chiang Mai, Thailand. Aeromonas spp. were the most dominant of the isolated species from the ornamental fish samples and accounted for 68.09% of the total. Other species detected included Vibrio spp., Pseudomonas spp., and Citrobacter spp. A high percentage of resistance to amoxicillin (93.75%), oxytetracycline (79.69%), and erythromycin (75.00%) was observed among the Aeromonas spp. The antimicrobial resistance information for ornamental fish is very limited, and the results from this study indicate that the Aeromonas spp. are highly resistant to several important antibiotics. The results suggest that additional steps should be taken to educate store owners to reduce the indiscriminate use of these antibiotics to decrease the antimicrobial resistance in ornamental fish to potentially improve public health.

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Pharmaceutical products of essential oil from Zingiber cassumunar Roxb. are extensively being developed, while the research on their safety is seldom documented. The aim of the present study was to evaluate the phytochemical profile and the effect of cassumunar ginger oil on cell-based assay and the zebrafish model. The essential oil was isolated from fresh rhizomes of Z. cassumunar using simultaneous steam-distillation. Chemical composition was analyzed using gas chromatograph coupled to a mass spectrometer (GC-MS). Effect of cassumunar ginger oil on adult carp fish peripheral blood mononuclear cells (PBMCs) was investigated using MTT assay. The embryotoxic and teratogenic effects of cassumunar ginger oil were studied in zebrafish embryos. GC-MS results showed that the essential oil was composed of sabinene (43.54%) and terpinen-4-ol (29.52%) as the major phytoconstituents. No fish PBMC cytotoxic effect was observed with the concentration less than 50 µg/mL of cassumunar ginger oil. Our results showed for the first time the embryotoxic and teratogenic effects of cassumunar ginger oil in zebrafish embryos. The result indicated that the cassumunar ginger oil induced zebrafish embryotoxicity in a concentration-dependent manner. At 500 µg/mL of cassumunar ginger oil demonstrated significantly moderated embryotoxicity within 24 h (p < 0.05). The survival rate of 100 µg/mL of cassumunar ginger group was markedly declined to zero at 96-h post-fertilization (log-rank test, p = 0.001). However, survival rates of zebrafish embryo in the 1 and 10 µg/mL cassumunar ginger groups were more than 90% throughout the trial period. Moreover, very low teratogenicity to the zebrafish embryo was also observed in 1 and 10 µg/mL of cassumunar ginger groups. Our findings suggest that there is hardly any cytotoxicity, embryotoxicity and teratogenicity at concentrations less than 10 µg/mL of cassumunar ginger oil. However, the toxicity assessment of its pharmaceutical product should prove for further consumer protection.

Zingiber ottensii Valeton (ZO) exhibits pharmacological activity and has long been used in traditional medicine. However, reports about its safety profiles are limited. The present study aimed to evaluate the phytochemical profile and the toxic effects of ZO essential oil on the development of zebrafish and acute oral toxicity in rats. The essential oil was isolated from ZO rhizomes, and phytochemicals were analyzed using a gas chromatography–mass spectrometer (GC–MS). The embryotoxic and teratogenic effects of ZO essential oil were evaluated in zebrafish embryos and larvae and the acute oral toxicity was determined in rats. GC–MS results showed the essential oil contained zerumbone as a major phytoconstituent (24.73%). The zebrafish embryotoxicity of ZO essential oil appeared to be concentration- and time-dependent manner, with a moderate LC50 (1.003 µg/mL). Teratogenicity in zebrafish embryos also included morphological defects, decreased hatchability, and reduced heart rate. In rats, ZO essential oil (2000 mg/kg, p.o.) resulted in no mortality or significant toxicities. These findings suggest that ZO has embryotoxic and teratogenic effects in zebrafish embryos but does not result in death or acute oral toxicity in rats. Further long-term toxicity studies are needed to confirm the safety of products developed from ZO essential oil.

This study explores the anaesthetic activity of Alpinia galanga oil (AGO) in fish. Cyprinus carpio (koi carp) was used as a fish model. It was found that the induction time to stage 3 anaesthesia and the recovery time of the fish after exposure to AGO were exponentially and polynomially correlated to AGO concentrations. The viability of normal blood cells of koi carp anaesthetized with 500 mg/L AGO was found to be higher than 90% for normal red blood cells and white blood cells and 89% for peripheral blood nuclear cells indicating nontoxicity of AGO to the fish. A concentration of 300 mg/L of AGO was the most suitable for anaesthetizing koi carp due to the safety and effectiveness aspects as being ideally fitted to anaesthetic criteria. This concentration gave the induction time of 205.55 ± 5.07 s and the recovery time of 202.50 ± 9.30 s. Determination of stress biomarker such as blood cortisol and glucose as well as gene expression showed that the blood cortisol level of the fish anaesthetized with AGO was similar to normal levels. Moreover, blood glucose level was significantly less increased than those anaesthetized with tricaine methanesulfonate. Gene expressions of the fish cortisol receptor, cytochrome oxidase subunit1, heat shock protein 70 and Na+/K+‐ATPaseα3 were significantly reduced after exposure to AGO indicating the advantages of AGO on fish stress reduction. Thus, AGO is a promising natural source for an alternative fish anaesthetics.