Volume 69, 2017

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    Effects of Dietary Phosphorus Levels on Growth Performance, Plasma Biochemical Parameters and Relative Gene Expression of Lipogenesis of Bighead Carp, Aristichthys nobilis
    ( 2017) Ji, K. ; Liang, H. ; Mi, H. ; Mokrani, A. ; Xie J. ; Liu, B. ; Ge X. ; Ren, M.
    An 8-week feeding trial was conducted to investigate the effects of dietary phosphorus levels on growth performance, plasma biochemical parameters, and lipogenesis gene expression of bighead carp. The results showed that weight gain (WG) and specific growth rate (SGR) increased with increasing dietary phosphorus levels up to 1.12%, and after that decreased. Feed conversion ratio (FCR) showed a converse trend compared with WG. Whole body protein and lipid contents significantly increased and decreased with increasing dietary phosphorus levels, respectively (P<0.05), whereas moisture and ash contents were not significantly affected by the dietary phosphorus levels (P>0.05). The highest values of the hepatosomatic index (HSI), total protein, and albumin contents were observed with 1.12% dietary phosphorus supplementation (P<0.05). Glucose levels increased with dietary phosphorus up to the level 1.32% phosphorus supplementation, and then decreased. Serum total cholesterol, total triglyceride, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphates activity were not significantly affected by dietary phosphorus levels (P>0.05). Excess phosphorus levels (1.32% and 1.59%) significantly down-regulated the relative gene expression levels of sterol regulatory element binding protein (SREBP) -1 and fatty acid synthase (FAS) (P<0.05). Based on WG and FCR, the optimal dietary phosphorus level should be 1.16%, using quadratic regression analysis.
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    Intestinal fatty acid binding protein gene (I-FABP) in golden pompano Trachinotus ovatus (Linnaeus 1758) larvae: ontogenetic expression and response to water temperature and nutrition manipulation
    ( 2017) Lin, M. ; Tang, X. ; Qin, J.G. ; Ma, Z. ; Wei, W
    The gene for fatty acid binding proteins (I-FABP) in golden pompano Trachinotus ovatus larvae was cloned and analyzed from hatch to 18 days-post hatch (DPH). The I-FABP gene (GenBank accession: MF034871) of golden pompano is composed of 815 bp with an open reading frame of 399 bp, encoded in one amino acid with a molecular weight of 15.24 kDa. The predicted amino acid sequence of I-FABP genes from golden pompano showed high similarity and identity with Japanese sea bass Lateolabrax japonicus (97% and 87.9%, AOW69620.1). The highest tissue expression of I-FABP genes was found in the intestine, followed by the eye on 18 DPH. During the ontogenetic development, the expression of I-FABP genes remained at a low level during the first five days, and reached the highest level on 12 and 18 DPH. The expression of I-FABP genes was not significantly affected by environmental temperature on 12 DPH, but was significantly affected by the temperature on 18 DPH. Nutrition enhancement with algae containing high fatty acids significantly affected the expression of I-FABP genes. The highest expression was observed in the non-enriched treatment, but the lowest expression was in the Nannochloropsis feeding treatment. Results of the present study indicate that the expression of the I-FABP gene varies with environmental temperature and nutritional conditions during the ontogenetic development of golden pompano larvae. The expression of I-FABP genes may be potentially used as an indicator for assessing nutrient supply and functional development of the digestive system in fish larvae.
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    Isolation and Characterization of Aeromonas veronii from Ornamental Fish Species in China
    ( 2017) Song, Y. ; Hu, X. ; Lü, A. ; Sun, J. ; Yiksung, Y. ; Pei, C. ; Zhang, C. ; Li, L
    Aeromonas veronii infection of fish has become a significant problem in aquaculture. In this study, pure bacterial cultures were isolated from diseased ornamental fish suffering high mortality rate in China. These fish included zebrafish (Danio rerio), goldfish (Carassius auratus), oscar (Astronotus ocellatus), parrotfish (Amphilophus spp.) and crucian carp (Cyprinus carpio koi). Using morphologic, physiological, and biochemical characteristics and 16S rRNA sequences analysis, nine isolates, namely strains ZG-1, ZG-2, DW-1, DW-2, KL-1, DT-116, LS-912, SJ-1 and SJ-2 were identified as A. veronii. A phylogenetic tree constructed on the basis of 16S rRNA sequences strongly indicated that the isolates were most closely related to the species A. veronii (98.43-100% similarities). The pathogenicity of the isolate was confirmed in zebrafish with median lethal dose (LD50) ranging between 1.15×106 CFU/mL and 3.94×108 CFU/mL. Antibiotic susceptibility tests showed that the isolated strains were all susceptible to cephalosporins and chloramphenicol. Furthermore, histopathology of zebrafish showed leukocyte infiltration of gill filaments, necrosis of the hepatic cell and glomerulus hemorrhage. These results will provide a scientific reference for the prevention, control, and understanding of the pathogenic mechanism of A. veronii infection in fish.
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    Stenotrophomonas maltophilia: an Emerging Pathogen of Ascites Disease in Farmed Yellow Catfish Pelteobagrus fulvidraco
    ( 2017) Haipeng, Cao H. ; Guo, C. ; An, J ; .Lu, L., ; Yang, X., ; Yang, Y.
    Ascites disease causes significant economic losses in yellow catfish Pelteobagrus fulvidraco. Yet only scare information is reported on Stenotrophomonas maltophilia as a pathogen for yellow catfish. In this study, a virulent strain, temporarily named WY1, was isolated from diseased yellow catfish fry suffering from ascites disease, identified phenotypically and molecularly as S. maltophilia. A phylogenetic tree was constructed to examine isolate WY1 and compare it to other known isolates. In addition, isolate WY1 is apparently susceptible to aminoglycosides and tetracycline drugs for veterinary uses in aquaculture as revealed when screened against a range of common antibiotics. To the best of our knowledge, this is the first report of S. maltophilia as a pathogen of ascites disease in farmed yellow catfish.
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    The Efficacy of Chamomile (Matricaria chamomilla l.) Oil as a Promising Anaesthetic Agent for Two Freshwater Aquarium Fish Species
    ( 2017) Can, E. ; Kizak, V ; Özçiçek, E ; Sehaneyildiz, C
    The efficacy of anesthetic chamomile oil (from Matricaria chamomilla L.) was evaluated in two freshwater aquarium fish species, Electric Blue Hap (Sciaenochromis fryeri) and Yellow Princess (Labidochromis caeruleus). Fish were exposed to ten concentrations of anesthetic (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1.0 ml/L). The optimal doses identified as 0.6 ml/L for deep anesthesia (A5) for both two species. The minimal sedative dose at the stage of loss of equilibrium (A3) was found to be 0.3 ml/L. The induction time generally decreased significantly with increasing concentrations of chamomile oil for all treatment groups. Recovery time tended to increase with increased chamomile oil at concentrations lower than 0.7 ml/L, but after this concentration it decreased. Chamomile oil proved to be effective as an anesthetic for both ornamental fish species. These findings suggest that chamomile oil is a promising anesthetic agent for aquaculture. However, further studies should be focused on species based investigations on the effect of temperature, transfer of fish, and their effect on antioxidant and oxidant status, in order to gather further information.
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    Six practical diets were formulated to contain 2.6 (the basal diet), 48.9, 95.5, 189.83, 382.4, 779.53 mg/kg vitamin C diet. After 8 weeks of feeding, growth performance, antioxidant status, and innate immunity of juvenile pufferfish were analyzed. Results showed that specific growth rate and protein efficiency ratio in fish fed diets supplemented with vitamin C were significantly higher than in fish fed the control diet. Dietary vitamin C significantly up-regulated the expression levels of growth hormone receptors and Insulin-like growth factor. Blood cell numbers and respiratory burst activity were enhanced in fish fed vitamin C diet. Serum alkaline phosphatase, glutamic-pyruvic transaminase, and glutamic-oxaloacetic transaminase activity were significantly influenced by the dietary vitamin C levels. Fish fed diets supplemented with vitamin C showed increased hepatic superoxide dismutase, glutathione peroxidase, and catalase activity, but decreased malondialdehyde activity. In addition, we found that dietary vitamin C can significantly up-regulate the expression levels of immune-related genes (HSP70, HSP90, BAFF, TNF-α and IL-6) in liver. These results indicate that dietary vitamin C can significantly influence growth performance, antioxidant status, and innate immunity of pufferfish.
    ( 2017) Cheng, C-H ; Liang, H-Y. ; Guo, Z-X. ; Wang, A-L ; Ye, C-X
    Six practical diets were formulated to contain 2.6 (the basal diet), 48.9, 95.5, 189.83, 382.4, 779.53 mg/kg vitamin C diet. After 8 weeks of feeding, growth performance, antioxidant status, and innate immunity of juvenile pufferfish were analyzed. Results showed that specific growth rate and protein efficiency ratio in fish fed diets supplemented with vitamin C were significantly higher than in fish fed the control diet. Dietary vitamin C significantly up-regulated the expression levels of growth hormone receptors and Insulin-like growth factor. Blood cell numbers and respiratory burst activity were enhanced in fish fed vitamin C diet. Serum alkaline phosphatase, glutamic-pyruvic transaminase, and glutamic-oxaloacetic transaminase activity were significantly influenced by the dietary vitamin C levels. Fish fed diets supplemented with vitamin C showed increased hepatic superoxide dismutase, glutathione peroxidase, and catalase activity, but decreased malondialdehyde activity. In addition, we found that dietary vitamin C can significantly up-regulate the expression levels of immune-related genes (HSP70, HSP90, BAFF, TNF-α and IL-6) in liver. These results indicate that dietary vitamin C can significantly influence growth performance, antioxidant status, and innate immunity of pufferfish.
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    Effects of Different Levels of Dietary Surfactin Supplementation on Intestinal Morphology, and Intestinal Microflora of Growth Retarded Marbled Eel Juveniles (Anguilla marmaorata)
    ( 2017) Zhai, S-W. ; Chen, X-H. ; Wang, M-H.
    This 70 day trial was conducted to investigate the effects of surfactin on intestinal morphology and intestinal microflora of growth retarded marbled eels (Anguilla marmorata). A total of six hundred and forty marbled eels at elver stage were randomly allocated to 4 treatment groups on the basis of body weight. There were 4 replicate tanks in each treatment group with 40 fish per tank. Four diets were formulated with four levels of dietary surfactin: 0, 25, 50, and 100 mg/kg, respectively. Fish were fed twice daily to apparent satiation for 70 days. Retarded marbled eels fed diets with surfactin supplementation had enhanced mucosa folds in their intestines (P<0.05). It seems that the quantity of mucosa folds increased with the increasing surfactin levels in the diet. Dietary surfactin supplementation decreased the E. coli population significantly (P<0.05), and increased the Lactobacillus population significantly (P<0.05), but had no effect on total bacterial population in intestines of marbled eels (P>0.05). Results of the present study indicate that surfactin improves intestinal function in retarded elvers of marbled eels.
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    Effects of Dietary Astaxanthin on Growth Performance, Hepatic Antioxidative Activity, hsp70, and HIF-1α Gene Expression of Juvenile Golden Pompano (Trachinotus ovatus)
    ( 2017) Xie, J-J ; Chen, X. ; Liu, Y-J ; Tian, L-X ; Xie, S-W ; Niu, J.
    The present study was conducted to investigate the effects of different astaxanthin (AST) levels on growth performance, hepatic antioxidative activity, heat shock protein 70 (hsp70), and hypoxia-inducible factor-1 alpha (HIF-1α) gene expression of juvenile golden pompano. Fish (mean initial body weight 5.8±0.05g) were fed six isonitrogenous and isoenergetic diets (AST-0, AST-0.005, AST-0.01, AST-0.05, AST-0.1, AST-0.2) containing various supplemented levels of astaxanthin (0%, 0.005%, 0.01%, 0.05%, 0.1%, 0.2%, respectively) in triplicate for 8 weeks. Growth performance (final body weight, FBW; weight gain, WG), and survival of fish fed diets containing astaxanthin above 0.01% were significantly higher (P<0.05) than of fish fed AST-0 and AST-0.005 diets; feed conversion ratio (FCR) showed the opposite trend (P<0.05). Fish fed 0.01% astaxanthin diet showed the highest value of survival. Hepatic antioxidant status (total antioxidant status, TAS; superoxide dismutase, SOD; carbonyl protein content) of shrimp improved significantly when dietary astaxanthin was over 0.01%. Relative expression profiles of hepatic hsp 70 mRNA and HIF-1α mRNA increased with increased dietary astaxanthin levels. The relative expression profiles of hepatic hsp 70 mRNA and HIF-1α mRNA of shrimp fed diets containing astaxanthin above 0.01% were obviously higher than those of shrimp fed AST-0 and AST-0.005 diets. Linear regression analysis on WG and HIF-1a mRNA indicated that the optimum dietary AST levels for optimal growth and immunity of juvenile pompano were 0.011% and 0.013%, respectively.
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    Polyculture of Sea Cucumber Holothuria scabra with Pacific White Shrimp Litopenaeus vannamei
    ( 2017) Jiang, S. ; Zhou, F. ; Mo, X., Huang, J. ; Yang, Q.,Y.
    An experimental study of polyculture of sea cucumber Holothuria scabra with Pacific white shrimp Litopenaeus vannamei was carried out in the laboratory. Results indicated that nutrient structure of the culture system was influenced significantly by the sea cucumber: the phosphate and nitrate concentrations were enhanced more obviously in the polyculture system (PS) than in the monoculture system (MS), but by contrast, the ammonium concentration remained low in the PS. The sulfide contents of the sediment were reduced in the PS to 10.32±1.85mg/kg, accounting for about 2/5 of that in the MS. The PS of sea cucumbers had positive effects on the growth and survival of shrimp, the specific growth rate of weight of shrimp in the PS was 2.89±0.63%/day and significantly higher than that of the MS (average 2.05±0.57%/d). Survival rate of the shrimp in PS was 79.3±22.9%, dramatically higher than that of the MS (average 64.0±17.5%). In the PS, the shrimp had no negative effect on the sea cucumbers who ingested and assimilated food residue in the sediment of the culture system with an assimilation efficiency of 42.06±10.62% for organic matter. PS of sea cucumber Holothuria scabra in the shrimp culture system had both environmental and economic benefits. This PS method could contribute to sustainable development of aquaculture in China
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    Shewanella putrefaciens: an emerging pathogen for farmed yellow catfish Pelteobagrus fulvidraco
    ( 2017) Yang, Yibin ; Guo, Cheng ; Cao, Haipeng ; Lu, Liqun ; Yang, Xianle
    Bacteriosis has caused significant economic losses in farmed yellow catfish Pelteobagrus fulvidraco. Information is limited on Shewanella putrefaciens as a pathogen for yellow catfish. In this study, a virulent strain, temporarily named Y2, was isolated from diseased yellow catfish, identified phenotypically and molecularly as S. putrefaciens. A phylogenetic tree was constructed to examine isolate Y2 and compare it to other known isolates. In addition, isolate Y2 is apparently susceptible to aminoglycosides and tetracycline drugs for veterinary use in aquaculture as revealed when screened against a range of common antibiotics. To the best of our knowledge, this is the first report of S. putrefaciens as an emerging pathogen for cultured yellow catfish.