Volume 70, 2018

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    Improved Sampling of Hemolymph and Screening of Anti-Coagulants of Hemocytes in the Snail Babylonia areolata
    ( 2018) Di, Guilan ; Zhu, Guorong ; Li, Yanfei ; Ke, Caihuan ; Zhang, Zhaoxia
    Our aim was to improve sampling of hemolymph from the snail Babylonia areolata in order to evaluate the physiological and immune capacities of hemocytes in aquaculture. We also identified appropriate types of hemolymph anti-coagulants for B. areolata. Hemolymph samples were collected using an improved foot plantaris puncture method. We screened five types of anti-coagulants from Penaeid shrimp (A), marine decapods (B), abalone (C), and oyster (D), as well as a home-made anti-coagulant (E), to act against Babylonia areolata hemocytes on the basis of cell death rate and hemocyte aggregation. We improved the former foot plantaris puncture method and identified the home-made anti-coagulant as the best anti-coagulant from the five which we tested.
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    Cyclopamine Induced Expression of Immune-related Genes in Rainbow trout (Oncorhynchus mykiss) Head Kidney Leukocytes
    ( 2018) Sõnmev, A.Y. ; Özdemir, R.C. ; Bilen, S. ; zdemit, Y.K.
    This study investigated the effect of cyclopamine, a hedgehog signaling inhibitor, on immune-related gene expression in rainbow trout head kidney leukocytes in vitro. At 1h sampling time COX 2, IFN-2, TNF-α, C3, MHC-II, Il-1β, IL-12, IL-10, and IL-6 increased significantly in groups exposed to cyclopamine at 30 μg/ml. However, in groups exposed to 10 and 20 μg/ml cyclopamine, the expression of these genes decreased significantly. At 4h sampling time, levels of COX-2, IFN-1, IFN-2, TNF-α, TGF-β, IgT, and MHC-II in groups exposed to 20 μg/ml cyclopamine increased. At 8h sampling time, COX2, IFN-Reg, and TNF-α expression in groups exposed to 10 and 30 μg/ml cyclopamine increased significantly compared to those in the controls. Conversely the expression decreased significantly for almost all other genes. At 12h sampling time, almost all genes increased significantly in groups exposed to 10 μg/ml cyclopamine compared to those in the controls. Notably, after 24h, the gene expression in all groups significantly decreased compared to the controls. Our results suggest that the activation of cyclopamine can be a useful tool for the examination of immune-related gene expression in the rainbow trout.
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    Effects of Dietary Surfactin Supplementation on Growth Performance, Intestinal Digestive Enzymes Activities, and Hepatic Antioxidant Potential of American Eel (Anguilla rostrata) Elvers
    ( 2018) Zhai, S-W. ; Zhao, P-Y. ; hi, Y ; Chen, X-H. ; Liang, Y,
    The 70-day trial was conducted to investigate the effects of surfactin on growth performance, intestinal digestive enzymes activities, and hepatic antioxidant potential on American eel (Anguilla rostrata) at elver stage. Six hundred American eel elvers were randomly divided into five treatments with three replicates per group, 40 fish per replicate. Dietary surfactin levels of the five treatment groups were 0, 25, 50, 100, and 200 mg/kg, respectively. Final body weight, weight gain rate, and feed efficiency were significantly affected by surfactin supplementation (P<0.05). There were no significant differences in feeding rate and survival rate among all groups (P>0.05). Protease and lipase activity in the intestine were significantly increased by surfactin supplementation (P<0.05), and amylase activity was similar among all groups (P>0.05). Malondialdehyde level, total antioxidation capacity level, and activities of superoxide dismutase, and glutathione peroxidase in intestine of fish were significantly (P<0.05) affected. No significant differences in CAT activities were found among all groups (P>0.05). The results demonstrated that dietary 25 mg/kg surfactin supplementation improves growth performance, some digestive enzyme activities in the intestine, and hepatic antioxidant potential of American eel at elver stage.
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    Effects of Dietary Protein and Lipid Levels on Growth Performance, Feed Utilization and Biochemical Parameters of Barbless Carp (Cyprinus pellegrini)
    ( 2018) Zhang, J. ; Zhang, X. ; Wan, H. ; Chen, L. ; Lin, B. ; Li, G. ; Wang, Q.D.
    An 8-week feeding trial was conducted to evaluate the effects of varying dietary protein (35%, 40%, 45%) and lipid (4%, 8%, 12%) levels with protein to energy (P/E) ratios ranging from 17.04 to 23.58 g protein/MJ on growth performance, feed utilization, and biochemical parameters of barbless carp (Cyprinus pellegrini). Fish fed diets with 40% protein exhibited higher thermal growth coefficient (TGC) and energy retention compared with fish fed the diets with 35% protein, higher protein efficiency ratio (PER), and protein retention, compared with fish fed diets with 35% and 45% protein. TGC and energy retention were significantly lower in fish fed the diets with 4% lipid compared to fish fed diets with 8% and 12% lipid. Fish fed the diet with 40% protein and 12% lipid had similar TGC as those fed the diets containing 8% and 12% lipid with 45% protein, but showed relatively better PER. Further, fish fed the diet with 40% protein and 12% lipid exhibited relatively lower plasma γ-glutamyl transferase, aspartate aminotransferase, and alanine aminotransferase activities, and total protein and blood urea nitrogen contents compared with fish fed the other diets. These results indicate that a diet containing 40% protein and 12% lipid with P/E of 19.38 g protein/MJ would be suitable for growth and health of barbless carp.
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    The Effects of High Temperatures on Survival Rates and Immunity of Saltwater Clam Meretrix meretrix from Different Geographical Populations
    ( 2018) Chen, S.H. ; Chen, A.H. ; Wu, Y.P. ; Zhang, Y. ; Cao, Y.
    High temperature has significant effects on the survival and immunity of organisms. In order to conduct a detailed investigation into the response of the saltwater clam Meretrix meretrix from different geographical populations (GuangXi, JiangSu, ShanDong, LiaoNing) to high temperatures, we examined the survival rates and antioxidant enzyme activities of these clams that were exposed to different temperature treatments (25°C, 35°C, 37.5°C, 40°C). Results showed that the survival rate of clams from GuangXi was highest at 40°C, followed by JiangSu. SOD and CAT activities of all the clams increased with the increasing temperatures, and then gradually decreased at 40°C over time. The expression levels of Hsp70 of M. meretrix from four populations were analyzed by qPCR sampled from the hepatopancreas after 72 h under different temperatures. Higher Hsp mRNA expression of GuangXi at 40°C indicated that clams of GuangXi have stronger high temperature resistance than those of the other geographical populations. Our findings provide a basis for the choice of cultured clams with a high temperature tolerance.
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    Effect of Psidium guajava and Phyllanthus acidus Leaf Extract on Immunostimulant Response of Nile Tilapia Against Streptococcus agalactiae Infection
    ( 2018) Kamble, M.T. ; Yakupitiyage, A. ; Salin, K.R. ; Chavan, B.R.
    A study was conducted to investigate the efficacy of diets supplemented with aqueous extract of plants consisting of leaf-extracts of Psidium guajava (PGLE), Phyllanthus acidus (PALE), and the mixture of PGLE and PALE at the rates of 5 and 10 g/kg in the feed of Nile tilapia Oreochromis niloticus. Following 12 weeks of feeding, the fish were challenged with Streptococcus agalactiae for 15 days. Immuno-hematological parameters were measured before and after the challenge. Results showed significantly enhanced innate immune parameters after administration of the plant extracts. Respiratory burst activity, phagocytic assay, and serum lysozyme content were 2 to 3 times higher than that of the control treatment; PGLE-10 group showed the highest values, while fish fed PGLE-10 had the highest post-challenge WBC, RBC, Hb, and Hct values compared to the control. Survival rates were higher in the groups with dietary supplementation of plant extracts compared to the control. The positive immuno-hematological impact of plant extracts show that these can be effectively used as alternative prophylactic and antimicrobial agents in Nile tilapia culture.
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    Padina caulescens and Schizochytrium sp. as Supplemented Feed in the Nursery Production of Penaeus vannamei Post Larvae Reared in Biofloc Systems
    ( 2018) Romero-García, P.G. ; Pacheco-Vega, M. ; Cadena-Roac, M.A. ; Valdez-González, F.J. ; Zavala-Leal, Ó.I. ; Godínez-Siordia, D.E. ; Blanco-Jarvio, A.
    The appearance of diverse diseases in cultured shrimp has led to the search for alternative prevention strategies. One of these alternatives is Biofloc technology (BFT). However, this requires further optimization. The objective of this work is to improve this system by adding microalgae (Schizochytrium sp.), probiotic bacteria (Lactobacillus fermentum), and macroalga (Padina caulescens), which in addition to maintaining the quality of water in the Penaeus vannamei culture, improves growth parameters at the maternity stage. We installed an experiment that included six different treatments in culture tanks containing 250 L of seawater each, and 500 shrimp (68 mg) m/3, and evaluated the results for 35 days, in which we gradually decreased the inert-feed to 50-75% and substituted it with 50-25% of P. caulescens. The results showed that, in comparison to the control, survival, and final weight of the shrimps improved and improved further with the use of probiotic bacteria, Schizochytrium sp. and P. caulescens and probiotic bacteria enabled a reduction of 50% of the inert feed. Therefore, we recommended the use of P. caulescens, Schizochytrium sp. (LPU-1), and L. fermentum (T-19) in BFT cultures for P. vannamei.
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    Pharmacokinetics and Tissue Residence of Various Doses of Levamisole in Crucian Carp at Different Water Temperatures
    ( 2018) Li, G. ; Liu, Y. ; Gao, C. ; Dai, X. ; Yang, B. ; Liu, T. ; Zu, X.
    The pharmacokinetics of levamisole in crucian carp, including the absorption, distribution, and clearance rates in different tissues, were studied at different temperatures and doses for the theoretical basis of proper usage and withdrawal time. The fish were divided into three groups denoted A, B and C. The A and B groups were treated once at a dosage of 5 mg/kg levamisole, at 19 ± 1°C and 26 ± 1°C water temperature, respectively. The C group was treated at a dosage of 20 mg/kg levamisole at 19 ± 1°C water temperature. Then plasma, muscle, hepatopancreas, and kidney tissues samples were collected and pretreated, then measured using an ultra performance liquid chromatography-ultraviolet method. Plasma data were analyzed using DAS 3.0 pharmacokinetics software. Total area under the curve (AUC0-t) and elimination half-life (t1/2z) had a negative correlation with water temperature, and a positive correlation with dosage. Apparent volume of distribution (Vz) and total clearance rate (CLz) was positively correlated with temperature, and a negatively correlated with dosage. Levamisole was absorbed quickly to reach its peak concentration. The drug concentration and residence time in hepatopancreal and kidney were considerably higher and longer respectively than in the muscle and plasma suggesting that the hepatopancreas and kidney may be important metabolic organs for levamisole.
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    Dietary Supplementation of Glycyrrhetinic Acid (GA) Promoting Lipid Lipolysis from Blunt Snout Bream Megalobrama amblycephala by TNF-α and LPL Expression
    ( 2018) Liu, M-y ; Liu, G-x. ; Zhou, M. ; Liu, W-b. ; Jiang, G.
    Glycyrrhetinic acid (GA), which is a main active principal constituent of liquorice, is extensively used as a non-nutrition sweetener or antiinflammatory in Chinese medicine. This study was carried out to evaluate the effects of different GA levels on growth, biometric parameters, plasma lipid metabolites, Tumor necrosis factor alpha (TNF-α) and Lipoprotein lipase (LPL) gene expression of Megalobrama amblycephala (average weight, 68.78 ±1.13 g). Three diets were formulated to contain various levels of GA (0, 30 and 300 mg/kg). Fish were randomly distributed into 12 cages and fed three times daily for 8 weeks. Dietary GA levels have little significant effect on weight gain and feed conversion ratio. Intraperitoneal fat ratio and viscera/body ratio decreased significantly as dietary GA levels increased, and hepatosomatic index tended to decrease as dietary GA levels increased. Plasma triglycerides, cholesterol, and non-esterified free fatty acid levels also decreased as dietary GA concentrations increased. Adipose tissue and liver TNF-α expression increased significantly with increasing dietary GA levels; whereas, LPL expression showed an opposite trend. Results of this study indicate that dietary supplementation of 300 mg/kg GA had a positive effect in promoting lipid lipolysis in Megalobrama amblycephala without having a negative effect on growth through the regulation of TNF-α and LPL expression.
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    Bacillus mycoides: An Emerging Pathogen of Ulcerative Disease in Farmed Largemouth Bass Micropterus salmoides
    ( 2018) Cao, H. ; Yang, Y. ; Lu, L. ; Yang, X. ; Ai, X.
    Ulcerative disease causes significant economic losses in largemouth bass Micropterus salmoides production. Yet information reported on Bacillus mycoides as a pathogen for largemouth bass is scarce. In this study, a virulent strain, temporarily named LYS1, was isolated from diseased M. salmoides suffering from ulcerative disease, identified phenotypically and molecularly as B. mycoides. A phylogenetic tree was constructed to examine isolate LYS1 and compare it to other known isolates. In addition, isolate LYS1 appears to be susceptible to aminoglycosides and quinolones drugs for veterinary use in aquaculture as seen when screened against a range of common antibiotics. To the best of our knowledge, this is the first report of B. mycoides as a pathogen of ulcerative disease in farmed largemouth bass