Production of all-male non-transgenic zebrafish by conditional primordial germ cell ablation.

Many fish species exhibit remarkable sexual dimorphism, with males possessing numerous advantageous traits for commercial production by aquaculture such as faster growth rate, more efficient food energy utilization for muscle development, and better breeding performance. Several studies have shown that a decrease in the number of primordial germ cells (PGCs) during early development leads predominantly to male progeny. In this study, we developed a method to obtain all-male zebrafish (Danio rerio) by targeted PGC ablation using the nitroreductase/metronidazole (NTR/Mtz) system.

An NGS-based approach for the identification of sex-specific markers in snakehead ().

We described a next generation sequencing (NGS)-based approach to identify sex-specific markers and subsequently determine whether a species has male or female heterogamety. To test the accuracy of this technique, we examined the snakehead (), which is economically important freshwater fish in China. Males grow faster than females, and there is significant interest in developing methods to skew breeding towards all-males to increase biomass yields.

Molecular identification and expression of the Foxl2 gene during gonadal sex differentiation in northern snakehead Channa argus.

Channa argus is one of the most commercially important fish species in China. Studies show that males of C. argus grow faster than females at the same age.

Arsenic contamination in the freshwater fish ponds of Pearl River Delta: bioaccumulation and health risk assessment.

This study investigated the extent of arsenic (As) contamination in five common species of freshwater fish (northern snakehead [Channa argus], mandrarin fish [Siniperca chuatsi], largemouth bass [Lepomis macrochirous], bighead carp [Aristichthys nobilis] and grass carp [Ctenopharyngodon idellus]) and their associated fish pond sediments collected from 18 freshwater fish ponds around the Pearl River Delta (PRD). The total As concentrations detected in fish muscle and sediment in freshwater ponds around the PRD were 0.05-3.

[Residues and potential ecological risk assessment of metal in sediments from lower reaches and estuary of Pearl River].

In order to investigate the heavy metal concentrations and their potential ecological risks in surface sediments of lower reaches and estuary of Pearl River, 21 bottom sediment samples were collected from lower reaches and estuary of Pearl River. Total contents of Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Sb, Pb and Hg in these samples were measured by the inductively coupled plasma mass spectrometry (ICP-MS) and the atomic fluorescence spectrometry (AFS) and using the index of geoaccumulation and the potential ecological risk index to evaluate the pollution degree of heavy metals in the sediments. Results indicated that the concentration of total Fe and total Mn were 41658.

Mercury biomagnification in the aquaculture pond ecosystem in the Pearl River Delta.

This is the first study to investigate the rate of mercury (Hg) biomagnification in the aquaculture pond ecosystem of the Pearl River Delta (PRD), China, by analyzing total mercury (THg) and methyl mercury (MeHg) concentrations in various species of fish at different trophic levels (TLs). Species representing a gradient of trophic positions in the aquaculture pond food chains were chosen for analyzing THg and MeHg concentrations. In this study, there were two kinds of the aquaculture pond food chains: (1) omnivorous (fish feeds, zooplankton, grass carp [Ctenopharyngodon idellus], and bighead carp [Aristichthys nobilis]) and (2) predatory (zooplankton, mud carp [Cirrhina molitorella], and mandarin fish [Siniperca kneri]).

Interferon regulatory factor-2 in orange-spotted grouper (Epinephelus coioides): gene, inductive expression pattern and subcellular localization.

Interferon regulatory factor 2 (IRF-2) is a multifunctional transcription factor which exhibits both transcriptional activating and repressing activities in the IRF family. In this study, we report an IRF-2 gene isolated from orange-spotted grouper (Epinephelus coioides). The 1854bp full-length cDNA sequence of EcIRF-2 has been cloned, encoding a putative peptide of 336 amino acids which is highly consistent with the feature of IRF family members.

[Investigation of quinolones in aquaculture environment of the Pearl River Delta].

The concentrations and distributions of three sorts of quinolones (norfloxacin, ciprofloxacin and enorfloxacin) in water, sediments and the tissues of 8 kinds of fishes from 7 sites in Pearl River Delta aquaculture regions (freshwater and marine) were determined by high performance liquid chromatography (HPLC) with fluorescence detector. Results showed that no quinolones were found in either fresh waterborne or marine water. Norfloxacin, ciprofloxacin and enorfloxacin in sediments collected from freshwater aquaculture region ranged from 5.