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Fish cell lines have become a useful tool to study in resource conservation, genetic breeding, diseases control, and environmental pollutants detection. The silver pomfret (Pampus argenteus) is a high‐valued marine fish species in aquaculture, which is seriously threatened by various fish diseases. In this study, a new cell line derived from P. argenteus liver (PaL) was established and characterized. PaL cells mainly consisted of fibroblast‐like morphology and multiplied well in Leibovitz's L‐15 medium supplemented with 15% foetal bovine serum and 3 ng/mL basic fibroblast growth factor at 22°C. Amplification of the Cyt b gene confirmed that the origin of PaL cells as P. argenteus. Chromosome analysis revealed that PaL cells had a diploid Karyotyp. The PaL cells were efficiently transfected with pEGFP‐N3 plasmids, indicating its potential application in foreign gene manipulation studies. The PaL cells were found to be susceptible to red sea bream iridovirus (RSIV) and the expression of immune‐related gene (TLR5) and apoptosis‐related genes (Bax, Cyt c3, CASP9) were upregulated. Furthermore, lipopolysaccharide and palmitic acid (PA) treatments decreased cell viability and up‐regulated the expression of inflammation related genes (IL‐8, IL‐1β). Meanwhile, PA incubation induced cell apoptosis by Bcl‐2‐regulated caspase activation. In conclusion, the newly established PaL cell line will be an appropriate in vitro tool for viral propagation and immune response. [ABSTRACT FROM AUTHOR]

Photoperiod has a great influence on the growth and ovarian development and maturation of fishes. To analyse the effects of photoperiod on growth and ovarian development of an important marine economic fish, silver pomfret Pampus argenteus, short photoperiod group (L:D = 8:16), control group (L:D = 12:12) and long photoperiod group (L:D = 18:6) were set up for 60 days. The growth performance, ovarian development, changes in hormones and key enzyme activities in the hypothalamic–pituitary−gonadal (HPG) axis and expressions of key regulatory genes in the HPG axis were studied under different photoperiod conditions. The results showed that the final weight gain, body weight index, specific growth rate for weight, specific growth rate for length and average daily growth were the highest in the long photoperiod group, and the feed conversion rate was the lowest. Under long photoperiod condition, gonado‐somatic index and hepato‐somatic index were higher, ovarian maturity was better and expressions of HPG axis−related regulatory genes foxl2a, foxl2b, cyp19a1a, cyp19a1b, kiss, gpr54‐2, gnrh2, fsh and lh were higher. When compared with the other two groups, in the long photoperiod group, the change trend of estradiol (E2) was consistent with those of luteinizing hormone, melatonin (MT) and kisspeptin, and the levels were higher on the 20th and 50th days. These results indicate that prolongation of the photoperiod can improve the growth performance of P. argenteus and promote ovary development and maturation. The authors speculate that photoperiod may regulate the ovarian activity of P. argenteus through MT and kisspeptin/gpr54 signalling pathways. The results show that photoperiod can regulate the ovarian development of P. argenteus, which would help in breaking the seasonal restrictions of animals and regulating an animal's reproductive cycle. [ABSTRACT FROM AUTHOR]

Silver pomfret (Pampus argenteus) is one of the most important fishery products in the Indo‐Pacific Ocean. Nonetheless, little is known about the genetic parameters of economic traits. To determine whether the selective breeding programme would improve economic traits, the authors evaluated the growth performance of the selected group and the control group at 60, 90 and 120 days, and the growth performance parameters of the selected group were higher than those of the control group. Through Pearson correlation analysis, the authors found that the morphological traits that are highly related to the weight of P. argenteus are body length and body height. Genetic gain and realized heritability for body weight were highest at day 90, which were 12.72% and 0.23%, respectively. Therefore, the authors speculate that day 90 may be a critical time for screening. The average coefficient of variation for body weight reached over 30%. All three morphological traits reached moderate realized heritability at day 90 after hatching. These implied that selective breeding has the potential to improve the growth traits of P. argenteus. In addition, the reproductive performance of P. argenteus parent fish was obviously improved after gonadal strengthening. These results provide important information for future breeding programmes for P. argenteus. [ABSTRACT FROM AUTHOR]

A cell line (PaF) derived from the fin tissue of silver pomfret (Pampus argenteus) was established and characterized in this study. The cell line has been subcultured for more than 50 times in Dulbecco's modified Eagle's medium (DMEM) containing 15% foetal bovine serum (FBS) since the initial primary culture. PaF cells grew well at temperatures from 24°C to 28°C in DMEM supplemented with 15% FBS. Partial amplification and sequence analysis of the cytochrome B gene indicated that PaF originated from silver pomfret. Cytogenetic analysis demonstrated that the modal chromosome number was 48. A significant cytopathic effect was observed in PaF cells during viral haemorrhagic septicaemia virus (VHSV) infection, and the VHSV replication was confirmed by qRT‐PCR and viral titre assays. In contrast, PaF cells were resistant to red‐spotted grouper nervous necrosis virus infection. Moreover, PaF cells could respond to VHSV and lipopolysaccharide treatments, as indicated by the expression of immune‐related genes, TLR5 and TLR9. In conclusion, the establishment of PaF cell line will provide an appropriate in vitro tool for the study of mechanisms of pathogen–silver pomfret interaction. [ABSTRACT FROM AUTHOR]