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Coilia nasus is an endangered fish species in the Yangtze River, and there is urgent need to know the genes related to its reproduction and fertility. The DAZ family including boule, daz and dazl, plays an important role in germ cells development. In this study, the cDNA sequence of boule (Cnbol) and dazl (Cndazl) genes were cloned and their expression patterns were characterized in Coilia nasus. RT-PCR showed that the expression of Cnbol and Cndazl mRNAs was restricted in adult gonads. The section in situ hybridization indicated that the temporospatial expression patterns of Cnbol and Cndazl were significantly different. In the testis, Cnbol was mainly detected in spermatocytes and spermatids, while Cndazl was prominently expressed in s permatogonia. In the ovary, Cnbol and Cndazl were highly expressed in the early stages of oocytes. Interestingly, Cndazl was also concentrated in perinuclear speckle and then localized to the Balbiani body in late stages of oocytes. In addition, Cnbol and Cndazl 3′ UTR can specifically label medaka Primordial Germ Cells (PGCs). According to our results, Cnbol and Cndazl are marker genes of germ cells and may play a vital role in the development and differentiation of germ cells in Coilia nasus.

This study was designed to generate the full-length transcriptome of Coilia nasus using single-molecule long read isoform sequencing (SMRT-seq) technology. RNAs of brains, ovaries, and testes of C. nasus conditioned in both seawater and freshwater except for gut which was only from the fish conditioned in freshwater, were isolated. All the RNAs were pooled together equally for SMRT sequencing. One SMRT cell produced 64.18 Gb clean data, including 765,184 circular consensus (CCS) reads and 616,126 full-length non-chimeric (FLNC) reads. Finally, 93,793 non-redundant transcripts were obtained after clustered and polished. Structural analysis of the 93,793 non-redundant transcripts predicted 8242 alternative splicing events, a total of 229,825 SSR and 72,037 complete CDS. A total of 8437 lncRNA were identified. 84,617 transcripts were annotated in NR, Swissprot, GO, COG, KOG, eggnog, Pfam and KEGG database totally. This is the first full-length transcriptome of Coilia nasus, including transcripts appeared in the case of seawater, which will facilitate exploration of genetic data and life story of Coilia nasus.

The effects of soybean antigenic protein on the gustatory receptor T1R1 mRNA expression and intestinal immune response were evaluated in the obscure puffer (Takifugu fasciatus; initial weight 39.84 ± 3.09 g). Fish were fed with eight different diets for two months; four of these were practical diets with either a high level of fish meal (FMH 2 ), a low level of fish meal (FML 3 ), a diet where FML was partially (18.6%) replaced by fermented soybean meal (FMLF 4 ), and a diet where FML was partially (18.6%) replaced by soybean meal (FMLS 5 ). Four other semi-purified diets were offered that contained different levels (0%, 5%, 8%, and 12.5%) of soybean antigenic proteins (AP0, AP5, AP8, and AP12.5, respectively). Feeding rate and intestine histological structure were investigated and the expression of IL-1mRNA, IL-10mRNA, and TNFmRNA in the intestine, HSP70mRNA in the liver, and T1R1mRNA in the tongue and intestine in four practical-diet groups and two semi-purified-diet groups (AP0% and AP8%) were also determined. The obtained results show feeding rate increased gradually as levels of soybean antigenic protein among the practical-diet groups, while the feeding rate of semi-purified-diet groups (AP5-AP12.5%) decreased and then increased with increasing soybean antigenic protein level. The expression level of T1R1mRNA in the tongue was higher than in the intestine; while they showed the same tendency, FMLS group was significantly higher than the control FML, AP8 group was significantly higher than AP0 group, and significantly lower than FMLS group (containing 8.8% soybean antigenic proteins similar with AP8 group). Soybean antigenic proteins did not affect the width of the intestine folds or the thickness of the muscular layer; however, they caused a difference in the height of intestine folds: higher soybean antigenic protein levels in the semi-purified-diet group led to lower height of the intestine folds with mild injuries in the intestine. The expression level of IL-1mRNA, IL-10mRNA and TNFmRNA in the intestine showed the same tendency as T1R1mRNA; and the expression level of HSP70 of FMLS group in the liver was significantly lower than in the control FML. No significant difference was found among most indexes between FMLF and FML. In conclusion, single or interacting antigenic proteins and other anti-nutritional factors may change the expression of gustatory receptor T1R1mRNA in both the intestine and tongue by affecting the intestinal health, and thus affected feeding. Excessive soybean antigenic proteins resulted in intestinal damage, therefore fermented soybean meal is better for partly replacement of fish meal than unfermented soybean meal.

Copper nanoparticles (Cu-NPs) are water pollutants, which has significant toxic environmental effects. However, the effects of Cu-NPs on Takifugu fasciatus are still relatively unknown. Compared with the control (no add CuSO4 and Cu-NPs). This study aims to describe the pathological changes in the gill and liver of pufferfish exposed to CuSO4 (Cu2+ for short) and Cu-NPs dissolved at a concentration of either 20 or 100 μg/L, in a semi-static waterborne exposure regime for 28 days. All Cu treatments resulted in organ injuries, and the pathologies observed following exposure to Cu-NPs were broadly of the same type as those observed following exposure to Cu2+. In the gill, these included lamellar fusion, clubbed tips, and mucocytes swollen, and in the liver included oedema, aggregation of blood cells, and necrosis. Furthermore, enzyme activity assays revealed that Ca2+ -ATP activity significantly increased under the influence of Cu, whilst Na+-K+-ATPase activity was significantly inhibited. In this study, the CRT in T. fasciatus (referred to as TfCRT) was identified and full-length cDNA sequences were characterized. Subsequently, RT-PCR and western blot analysis were carried out to assess the expressions of TfCRT in the gill and liver at both the mRNA and protein levels. Under both the Cu-NPs and Cu2+ treatments, both the mRNA and protein expressions of TfCRT were considerably higher in the gill and liver compared to that of the control treatment. Furthermore, there were no significant differences between Cu-NPs and Cu2+ treatment (at the same treatment concentration) in the expressions of TfCRT at the mRNA or protein levels. Overall, both Cu2+ and Cu-NPs had negative effects on T. fasciatus, and Cu-NPs had the toxic effects similar to dissolved Cu. Our results provide the ecological safety data service of Cu-NPs in water, and provide a reference for the health T. fasciatus aquaculture.

This study was carried out to determine the effects of abrupt salinity change on osmoregulatory ability of the spottedtail goby Synechogobius ommaturus. 720 juvenile fish (65.3 ± 11.8 g) were transferred to 200 L tanks (with 40 juveniles in each tank), in which salinities were abruptly changed from 10 to 20, 30, 40, 50 and freshwater. Survival rate, serum osmolality, electrolytes (Na+, Cl−, and K+) and gill Na+/K+-ATPase (NKA) activity were assessed successively in 528 h. Results showed serum osmolality, ion concentrations and gill Na+/K+-ATPase activity increased significantly when fish were transferred to salinity 40 and 50 and all fish in these groups died by the end of the experiment. Serum osmolality, Na+, Cl− and K+ in fish transferred to a salinity of 20, 30 and freshwater were not affected and no mortality was detected. Compared with the control group, a significantly decrease of NKA activity happened in the freshwater group, but the activity in 20 and 30 groups was not affected significantly. The results indicated that S. ommaturus could adapt rapidly and maintain homeostasis in a wide range of salinities (from freshwater to salinity 30) and this species may be suitable for aquaculture in estuarine and coastal areas where rapid salinity fluctuations commonly occur. Keywords: Osmolality, Gill, Na+/K+-ATPase, Synechogobius ommaturus

The anadromous Japanese Grenadier Anchovy Coilia nasus is a commercially important fish that is mainly distributed in the Yangtze River and its estuarine area. Two trials were performed to determine the effect of acute salinity stress on the survival of early C. nasus larvae at 0 d posthatch (DPH) and 2 DPH. The salinity treatments for these two trials were 0.4, 5, 10, 15, 20, and 25‰. A third trial compared the growth of juveniles in 3, 6, 9, 12, 15, and 18‰ salinity. Larvae could only tolerate a limited range of salinity ( 12‰) caused low survival, and low salinity (

Acute and chronic experiments were conducted to evaluate the effect of salinity on survival and growth of the juvenile Dark Sleeper Odontobutis potamophila. For the acute experiment, half-lethal concentrations (LC50) of salinity for the juvenile Dark Sleeper after exposures for 12, 24, 48, 72 and 96 h were determined. Mean survival time (MST) and half-survival time (ST50) at salinity of 32‰ were also recorded. For the chronic experiment, a 22-day trial focused on comparing the effects of different salinity levels (0, 2, 4, 6, 8, and 10‰) on survival rate and growth of the juvenile Dark Sleeper. Results revealed that the 96-h LC50 was 13.79‰ salinity. MST and ST50 at 32‰ were 35.4 min and 37.0 min, respectively. In the 22-d trial, survival rate and specific growth rate (SGR) decreased with salinity. Survival rate of groups in 8‰ and 10‰ salinity were significantly lower than that of other groups. The SGR for body length and body weight of the 10‰ group was significantly lower than that of the othe...

To determine the optimal condition of photoperiod for embryo development and larval culture of tawny puffer, Takifugu flavidus, the effects of photoperiod on egg hatching and the growth and survival of larvae from 3 to 23 d after hatching (dah) were assessed. The results show that photoperiodic responses varied with the developmental stage during the early development of tawny puffer. Photoperiod did not significantly affect the hatch rate, viability of 24 h post‐hatch larvae, and total mortality rate of tawny puffer embryos; however, it affected the incubation period, which significantly increased with increasing photoperiod from 6 to 24 h. The shortest incubation period was predicted to occur at 3.56 h day length from the quadratic relationship. However, photoperiod strongly affected the growth and survival of the tawny puffer larvae from 3 to 23 dah. Increasing the day length resulted in improvement of the larval growth and survival within the 0–12 h day length range; however, beyond the 12 h day length, a longer day length was not beneficial, and a 24 h continuous light had a negative effect on growth. From the quadratic relationships, the highest growth and survival rates were predicted to occur at 14.16 h and 17.74 h day length, respectively. Therefore, the optimal photoperiods for tawny puffer embryos and larvae were 3–6 and 12–18 h day length, respectively. The results of this study are useful in increasing the production of the species during incubation and larval culture.

To determine the effective LHRH‐a dosage for cultured tawny puffer ovulation, the effects of 10, 30, 50, and 70 I¼g kg−1 body weight (BW) LHRH‐a were tested with two injections in 2009, and by a single injection (5, 10, 30, 50, and 70 I¼g kg−1 BW) in 2010. Ovulation success and egg quality were assessed. All females spawned after being treated with 10 to 70 I¼g kg−1 BW LHRH‐a in 2009 and 2010. Ovulation success was only 20.0% with the 5 I¼g kg−1 BW treatment, significantly lower (P   0.05) among the 10, 30, 50, and 70 I¼g kg−1 BW treatment groups in terms of ovulation success, ovulation time, egg production, fertilization rate, hatch rate, and viability of 24 h post‐hatch larvae in 2009 and 2010. None of the treatments caused any mortality among the females during the experimental periods. Results suggest that the treatment using only LHRH‐a effectively and reliably induces ovulation in cultured tawny puffer broodstocks, whether through a single injection or through two injections. Effective and most economical dosage of LHRH‐a is 10 I¼g kg−1 BW. Determination of the effective LHRH‐a dosage is an important step in the development of tawny puffer fish culture.

Tawny puffer Takifugu flavidus is a species found in China considered to have potential for aquaculture. Experiments were conducted to determine the optimal temperature for its incubation and larval culture. Fertilized eggs collected from cultured broodstocks that were induced to ovulate with a [d-Ala6-Pro9-Net]-luteinizing hormone-releasing hormone analogue were inseminated. The effect of temperature (19, 20, 23, 26 and 29 °C) on the hatch rate, incubation period, viability of 24 h post-hatch larvae and total mortality rate was assessed. The effect of temperature (20, 23, 26 and 29 °C) on the growth and survival of larvae from 3 to 19 days after hatching (dah) was also assessed. The results showed that the optimal temperature for successful development of fertilized eggs ranged from 23 to 26 °C, and the highest hatch rate, the optimal viability of 24 h post-hatch larvae and the lowest total mortality rate were all predicted using quadratic equations. The relationship between temperature and the incubation period of tawny puffer eggs was determined using the effective degree-day model. The temperature at developmental zero (t0) was 11.34 °C, and the sum of effective degree-days (k) was 52.356. The survival rate of tawny puffer larvae at 20 °C was significantly lower than among 23, 26 and 29 °C, whereas the survival rate was not significantly different from that at 23, 26 and 29 °C. The larval growth rate increased rapidly as the temperature increased, showing a linear relationship in the range of temperatures investigated. The optimal temperature for larval culture ranged from 23 to 29 °C.

The effects of photoperiod, temperature, and salinity on growth and survival of obscure puffer Takifugu obscurus larvae were determined from 3 to 19 days after hatching (dah). The results showed that the optimal photoperiod for obscure puffer larvae was under continuous light conditions (24 h light:0 h dark). Increasing daylength resulted in improved larval growth and survival. Larvae cultured under total darkness grew very slowly and even negatively, and all died within 12 days (15 dah). The optimal and critical high temperatures for obscure puffer larvae were at 22–23 and 32 °C, respectively. The specific growth rates (SGR) of obscure puffer larvae increased with an increase in temperature from 20 to 29 °C, while no corresponding increase in SGR was observed for temperatures from 29 to 32 °C. Larval survival rate significantly decreased when the temperature increased from 23 to 32 °C, and there was a tendency for a low survival rate at 20 °C. A high salinity (25‰) resulted in reduced larval growth and survival probabilities. The highest survival and specific growth rates were both predicted to occur at 8‰ to 10‰ based on quadratic equations. High SGR (5.71–6.14% d − 1 ) and survival rates (> 90%) were found within a wide salinity range (0–20‰). The optimal and suitable salinity ranges of larviculture were 8–10‰ and 0–20‰, respectively. Therefore, obscure puffer larvae can feasibly be cultured in brackish water (0–20‰) existing in majority of coastal areas.

The respiratory rates of Tawny puffer Takifugu flavidus juvenile were measured at four temperatures (20, 23, 26 and 29 °C) and seven salinities (5, 10, 15, 20, 25, 30 and 35 g L−1). The results showed that both temperature and salinity significantly affected the oxygen consumption of tawny puffer juvenile. The oxygen consumption rate (OCR) increased significantly with an increase in the temperature from 20 to 29 °C. Over the entire experimental temperature range (20–29 °C), the Q10 value was 1.59, and the lowest Q10 value was found between 23 and 26 °C. The optimal temperature for the juvenile lies between 23 °C and 26 °C. The OCR at 25 g L−1 was the highest among all salinity treatments. The OCRs show a parabolic relationship with salinity (5–35 g L−1). From the quadratic relationship, the highest OCR was predicted to occur at 23.56 g L−1. The optimal salinity range for the juvenile is from 23 to 25 g L−1. The results of this study are useful towards facilitating an increase in the production of the species juvenile culture.

Tawny puffer Takifugu flavidus is a fish species that has aquaculture potential in China because of its high market value. To determine the optimal condition of salinity for embryo development and larval culture of the species, the effects of salinity (0‰, 5‰, 10‰, 15‰, 20‰, 25‰, 30‰, 35‰, 40‰, and 45‰) on egg hatching and the survival and growth of larvae at 3–23 days post-hatch (dph) were assessed. Embryonic hatching rates were above 70% at salinities of 5‰ to 45‰, and all embryos at 0‰ died 4 days after fertilization. Survival rates (> 75%) of larvae at 24 h post-hatch at salinities of 10‰ to 40‰ were significantly higher than that at salinities of 5‰ and 45‰. The highest hatching rates and lowest percentage of mortalities occurred at salinities of 10‰ to 20‰. Results suggest that the embryos can tolerate a wide range of salinity (10–40‰), and optimal range of salinity for embryo development is between 10‰ and 20‰. The time of egg hatching was not influenced by salinity. Larvae of tawny puffer continued to survive until Day 23 of post-hatch at salinities of 5‰ to 35‰, but all larvae died within 20 dph at 45‰. The highest survival rate occurred at salinities of 15‰ to 35‰, and the highest growth rate was found at salinities of 15‰ to 25‰. The results suggest that the optimal salinity for larval survival and growth is between 15‰ and 25‰.

In order to understand the muscle nutrient characteristics of the sword prawn Parapenaeopsis hardwickii,the nutritional composition and quality of muscles from the wild and cultured sword prawn were investigated and analyzed by biochemical analysis methods.The results show that the crude fat content of wild group(0.89%)was significantly lower than that of cultured group(1.12%),while the crude ash content of wild group(1.44%)was significantly higher than that of cultured group(1.31%).No significant difference in moisture and crude protein contents of fresh muscles was found between wild(79.42% and 17.94%,respectively)and cultured group(79.28% and 17.95%,respectively).18 kinds of amino acids were found in muscles from wild and cultured groups,and there was no significant difference in the content of 9 kinds of amino acid between wild and cultured groups,while in other 9 kinds of amino acids,the amino acid content of cultured group was significantly higher than that of wild group.Total amino acid(TAA),total essential amino acid(EAA),total non-essential amino acid(NEAA),total delicious amino acid(DAA),and total shrimp flavor amino acid(SAA)content of cultured group(88.08,30.53,47.39,34.47,and 21.72%,respectively)were significantly higher than those of wild group(83.42,29.69,43.59,32.54,and 21.11%,respectively).The essential amino acid index(EAAI)and the ratio of branched chain amino acid to aromatic amino acid(F value)of cultured group(69.10 and 2.12,respectively)were significantly higher than those of wild group(66.41 and 2.07,respectively).The saturated fatty acids(∑SFA)and poly-unsaturated fatty acids(∑PUFA)relative content of cultured group(39.60% and 36.64%,respectively)were significantly lower than those of wild group(41.95% and 39.51%,respectively),while the mono-unsaturated fatty acids(∑MUFA)relative content of cultured group(23.76%)were significantly higher than that of wild group(18.54%).The EPA+DHA relative content of wild group(28.23%)was significantly higher than that of cultured group(25.66%),while no significant difference was observed in the EPA+DHA absolute content of muscle between wild and cultured groups.Therefore,the sword prawn is nutritional,delicious,and artificial culture did not cause abundant accumulation of fat in muscle;on the contrary,it improved protein nutritive value of the muscle.