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Huang H.-H.,Northwest University, China | Liu X.-L.,Northwest University, China | Xiang J.-H.,CAS Qingdao Institute of Oceanology | Wang P.,Nanjiang Marine Biotechnology Company Ltd

To investigate the immune response of Litopenaeus vannamei to Vibrio infection, two L. vannamei groups, Vibrio-resistant shrimp and normal shrimp, were injected with a pathogenic strain of Vibrio harveyi at a dose of 1.0×105cfushrimp-1, and then their Vibrio density, total hemocyte count (THC), hemocyanin concentration, and the activity of phenoloxidase (PO), superoxide dismutase (SOD) and anti microbial peptides (AMPs) were determined. Results showed that resistant shrimp and normal shrimp cleared the V. harveyi infecting hemolymph during 3h and 12h after injection, respectively. The level of THC, hemocyanin concentration, and the activity of PO, SOD and AMPs in resistant shrimp was significantly higher at the beginning, and earlier decreased and recovered after injection than that in normal shrimp, respectively. In conclusion, hemocyte, hemocyanin, PO, SOD and AMPs were important for the response of both resistant and normal L. vannamei after V. harveyi injection, and the immune response in resistant shrimp was more efficient than that of normal shrimp. © 2013 Elsevier B.V. Source

Huang H.-H.,Northwest Agriculture and Forestry University | Liu X.-L.,Northwest Agriculture and Forestry University | Xiang J.-H.,CAS Qingdao Institute of Oceanology | Wang P.,Nanjiang Marine Biotechnology Company Ltd
Fish and Shellfish Immunology

To obtain Vibrio harveyi-resistant Litopenaeus vannamei shrimp used for study on immune response of shrimp avoid vibriosis, a three-round challenge selection procedure was applied. In this procedure, resistant shrimp were selected gradually via three rounds challenge experiment with a pathogenic strain of V. harveyi at a median and controllable lethal dose of 96-h LD50 (the median lethal dose). After this procedure, the cumulative mortality of selected shrimp during 96h after injection of V. harveyi at 2.0×106cfu shrimp-1 significantly decreased from 93.3% to 26.7%, the hours of beginning of death and the hours of attaining of the maximum cumulative mortality of shrimp prolonged from 4h and 10h to 8h and 24h, respectively. The LD50 of 6h, 12h, 24h, 48h and 96h of selected shrimp significantly increased to 1.4±0.1×107 (p<0.01), 5.5±0.4×106 (p<0.01), 3.1±0.2×106 (p<0.01), 2.7±0.1×106 (p<0.01) and 2.7±0.1×106cfu shrimp-1 (p<0.01), about 15.9, 15.3, 9.4, 10.0 and 10.4 times of that of normal shrimp, respectively. In conclusion, the resistance of shrimp to Vibrio significantly increased after the three-round challenge selection procedure. © 2013 Elsevier Ltd. Source

Andriantahina F.,Northwest University, China | Liu X.,Northwest University, China | Huang H.,Nanjiang Marine Biotechnology Company Ltd | Xiang J.,CAS Qingdao Institute of Oceanology | Yang C.,Animal Husbandry and Veterinary Station of Chenggu County

The present study was conducted to compare the reproductive performance and offspring quality of pond-reared (PR) and tank-reared (TR) Litopenaeus vannamei. There was no significant difference in the spawning frequency, fecundity, egg spawning success rate, number of eggs per spawning, and egg hatchability between the TR and PR females (P>0.05). However, PR females matured and spawned more rapidly after ablation and more often than TR females. Significant variations in the offspring quality of the broodstock from the two sources (TR and PR) were found. The larval stage index (LSI) at zoea III (Z III), mysis III (M III), and 5days post metamorphosis from mysis to postlarval stage 1 (PL 5) was very different (P<0.05) between the treatments. Nevertheless, the group of PR breeders resulted in significantly shorter postlarval stage periods (7days) than the group of TR breeders (9days) (P<0.05). The survival percentage up to 15days post metamorphosis from mysis to postlarval stage 1 (PL 15) stage of the PR breeders was significantly higher (74%) than for the TR (56%) sources (P<0.05). In general, the PR broodstock resulted in better offspring quality than the TR broodstock. This knowledge may also add to the development of improved hatchery protocols and help sustainable development of L. vannamei farming industry in the future. © 2011. Source

Qian Z.,Northwest University, China | Liu X.,Northwest University, China | Wang L.,Northwest University, China | Wang X.,Northwest University, China | And 3 more authors.
Comparative Biochemistry and Physiology - C Toxicology and Pharmacology

Heat shock proteins (HSPs) are a suite of highly conserved proteins well known for their quick responses to environmental stresses. However, the respective roles of different HSPs in response to a particular environmental stress have not received adequate scientific attentions to date. In this study, the expression profiles of four HSP genes (Lvhsp60, Lvhsp70, Lvhsc70, and Lvhsp90) of the Pacific white shrimp, Litopenaeus vannamei under acute thermal stress, pH challenge, and heavy metal exposure were investigated, respectively, using the quantitative real-time reverse transcription polymerase chain reaction technique. Results showed that the four genes exhibited quite different expression profiles when the shrimp were subjected to each of the above stressors. Under acute thermal stress, the messenger RNA (mRNA) levels of all the four genes were significantly induced, and the transcription level of Lvhsp70 was the most sensitive to temperature fluctuations. Under acute pH challenge, the relative mRNA expression of the four genes was shown to be time and pH dependent, and the strongest response occurred in Lvhsp60. Under acute heavy metal exposure, transcripts of each of the four genes varied depending on metal type and exposure time. Lvhsp60 displayed particularly high sensitivity to cadmium and manganese exposure, while Lvhsp70 showed the most sensitive response to iron and zinc treatments. The results obtained suggest that different LvHSP genes may play different roles in mediating cell stress caused by a specific environmental stressor. Given the response sensitivity and intensity of LvHSP genes to environmental stresses, Lvhsp70 may be most suitable to act as a biomarker indicating thermal stress, iron and zinc stimulation, while Lvhsp60 may be a promising candidate marker of pH stress, cadmium and manganese exposure in shrimp. © 2012 Elsevier Inc. Source

Qian Z.,Northwest University, China | He S.,Northwest University, China | Liu T.,Northwest University, China | Liu Y.,Northwest University, China | And 6 more authors.
Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology

Ecdysteroids initiate signaling along multiple pathways that regulate various aspects of development, maturation, and reproduction in arthropods. This study was carried out to seek the late target genes of ecdysteroid signaling from different tissues of the Pacific white shrimp, Litopenaeus vannamei. In the present study, eight isoforms of ecdysteroid receptor (EcR), two isoforms of retinoic acid X receptor (RXR), and one homolog of E75 were characterized from L. vannamei. The overall protein sequences and specific functional sites of EcR, RXR and E75 among crustacean species were found highly conserved. Tissue-specific, development stage-specific, and molt stage-specific expression patterns of LvEcR, LvRXR, and LvE75 were detected by qPCR. Double stranded RNA (dsRNA)-mediated RNA interference (RNAi) of any one of the three genes LvEcR, LvRXR and LvE75 caused specific expression changes of the other two, and resulted in corresponding expression changes of two molting related genes Cathepsin-L (LvCHSL) and Hemocyanin (LvHCyn) in the hepatopancreas, two chitin metabolism related genes chitin synthase (LvChS) and chitinase isoenzyme (LvChi2) in the epidermis, and two muscle growth related genes LvActin and myosin heavy chain (LvMHC) in the muscle. In correspondence, after in vivo injections of 20 hydroxyecdysone, specific expression changes of LvEcR, LvRXR, LvE75, LvCHSL and LvHCyn in the hepatopancreas, LvEcR, LvRXR, LvE75, LvChS and LvChi2 in the epidermis, and LvEcR, LvRXR, LvE75, LvActin and LvMHC in the muscle were also observed, respectively. Results in our study indicate multiple functions of ecdysteroids signaling in L. vannamei and the function may be time- and space-specific; ecdysteroids may act through different pathways via its functional receptor heterodimer EcR-RXR and the early responsive gene E75 to perform specific regulation roles on the target genes in different shrimp tissues; LvCHSL and LvHCyn in the hepatopancreas. , LvChS and LvChi2 in the epidermis, and LvActin and LvMHC in the muscle are potential targets for ecdysteroid control. This is the first report on nuclear receptors in the economically important shrimp L. vannamei. © 2014 Elsevier Inc. Source

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