bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Antibacterial Peptide Extracted from Bacillus subtilis fmbJ on the Growth, Physiological Response and Disease Resistance of Megalobrama amblycephala
Authors: He Yijin , Liu Bo , Xie Jun , Ge Xianping , Xu Pao , Lu Ying , Lu Fengxia , Lu Zhaoxin
Published: February 2021

The effects of an antibacterial peptide obtained from Bacillus subtilis fmbJ on growth, serum lysozyme complements 3 and 4, total protein content, aspartate aminotransferase (AST), alanine aminotransferase (ALT), total antioxidative capacity, superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and disease resistance of Wuchang bream (Megalobrama amblycephala) were examined. Fish were randomly divided into five groups: a control group which was fed a basic diet, and four groups fed the basic diet supplemented with 0.1%, 0.2%, 0.4%, or 0.8% antibacterial peptide. At eight weeks, M. amblycephala fed the diet containing 0.2% antibacterial peptide had higher serum lysozyme activity, complement 3 and 4 contents, and SOD activity than the control fish, but lower serum MDA content and AST activity. Fish fed the 0.4% diet had higher weight gain rate, serum lysozyme activity, complement 4 content, total antioxidative capacity, and total protein than the control, and lower serum ALT activity. Feed conversion ratios of fish fed the 0.2% or 0.4% diets were lower than those of control fish. Artificial infection with Aeromonas hydrophila resulted in 93% cumulative mortality in the control group, and 61-84% in the groups fed the 0.2% or 0.4% diets. The present study suggests that feed supplementation with 0.2-0.4% antibacterial peptides can stimulate immunity, increase resistance to pathogenic infection, and promote growth in M. amblycephala.
Effects of Methisoprinol on Innate Immunity Parameters in Intensively Reared European Eel (Anguilla anguilla)
Authors: Siwicki Andrzej Krzysztof , Lepa Agnieszka , Robak Stanisław , Kazuń Krzysztof , Kazuń Barbara , Głąbski Edward
Published: February 2021

Stress and chemotherapeutics can negatively affect the immune system of fish in intensive culture. Methods of prevention include immunonutrition. The present study examined the influence of dietary supplementation with the synthetic compound methisoprinol on selected nonspecific immune parameters in intensively cultured juvenile European eel (Anguilla anguilla). The fish were fed a commercial pellet containing 0 (control) or 200 mg methisoprinol/kg feed. After four weeks, the following immunological parameters were measured: respiratory burst activity and potential killing activity of the phagocytes, lymphocyte proliferation after stimulation by concanavaline A or lipopolisaccharide, and serum lysozyme activity, ceruloplasmin activity, total protein, and total immunoglobulin. Except for serum ceruloplasmin activity and total protein, all immune parameters were significantly higher (p<0.05) in the methisoprinol-treated group than in the control, strongly suggesting that four weeks of feeding methisoprinol to juvenile eels might improve innate immunity.
Infections by Lactic Acid Bacteria in Marine Fish from Southern Israel (Red Sea): New Records
Authors: Ucko M. , Colorni A.
Published: February 2021

Gram-positive chain-forming bacteria were isolated from the spleen, kidney, and blood of dead wild Red Sea fish (broomtail wrasse Cheilinus lunulatus, grouper Epinephelus fasciatus, goatfish Parupeneus sp.) that washed ashore on the Eilat Nature Reserve beach (Israel, Red Sea). Gram-positive bacteria were similarly isolated from rabbitfish Siganus rivulatus, white grouper Epinephelus aeneus, and grey mullet Mugil cephalus cultured in the Israel Oceanographic and Limnological Research, National Center for Mariculture, Eilat. On the basis of their phenotypical characteristics and 16S rRNA gene partial sequence analyses, the bacteria were identified as Streptococcus parauberis (from C. lunulatus), Lactococcus lactis (from E. aeneus and M. cephalus), Streptococcus iniae (from E. fasciatus, Parupeneus sp. and S. rivulatus), Streptococcus agalactiae (from M. cephalus), and Carnobacterium sp. (from E. aeneus). These lactic acid bacteria, isolated between 2009 and 2011, are added to the growing list of bacterial pathogens detected in wild or farmed marine fish in the Gulf of Eilat in recent years, suggesting a rising trend in areas subjected to intense anthropogenic impact (including aquaculture), where newly emerging pathogens and previously unexposed host populations are brought together.
Effects of Dietary Incorporation of Tetra (Cotinus coggygria) Extract on Immune Response and Resistance to Aeromonas hydrophila in Koi Carp (Cyprinus carpio)
Authors: Bilen Soner , Yılmaz Sevdan , Bilen Aslı Müge , Biswas Gouranga
Published: February 2021

In this study, immunostimulant effects of dietary supplementation of tetra (Cotinus coggygria) extract on the non-specific immune response, and protection against Aeromonas hydrophila infection in Koi carp (Cyprinus carpio) were investigated. Koi were fed with tetra extract incorporated diets containing 0 (Control), 0.5 (Te1), 1.0 (Te2) and 1.5 g/kg (Te3), for 30 days. At the end of the study there were no differences in the values of hematological parameters between treatments. However, red blood cell counts were significantly increased (P<0.05) in Te2 group. Nitroblue tetrazolium activity was higher in all the treatment groups compared to the control, and highest values were recorded in Te3, Te1 and Te2 groups, respectively. Lysozyme and myeloperoxidase activity of the treatment groups was significantly enhanced compared to control (P<0.05), and higher values of lysozyme and myeloperoxidase activity were seen in Te3, Te2 and Te1 groups, respectively. In the challenge study with A. hydrophila (108 CFU/ml) administered after 30 days of feeding where the Koi received Te3, Te2, Te1, and control diets, they had 13.3, 20.0, 26.7, and 40.0% mortality, respectively. Tetra extract supplemented diets enhanced the immunological responses and triggered the immune system of Koi carp against A. hydrophila infection.
Effects of Dietary Quercetin on the Growth Performance, Digestive Enzymes and Antioxidant potential in the Hepatopancreas of Tilapia (Oreochromis niloticus)
Authors: Zhai Shao-Wei , Liu Shu-Lan
Published: February 2021

This trial was conducted to investigate the effects of Quercetin on the growth performance, activities of digestive enzymes, and antioxidant potential in the hepatopancreas of tilapia. Four hundred tilapia (Oreochromis niloticus), were randomly divided into five treatment groups with four replicates in each group/ 20 fish per replicate. The dietary Quercetin levels of the five treatment groups were 0, 200, 400, 800, and 1600 mg/kg, respectively. The trial period was 49 days. Rates of weight gain, special growth, feed conversion, and protein efficiency ratio of the Quercetin diet groups improved significantly (P<0.05) compared with the control group. No significant difference in survival rates were found between the control group and all Quercetin diet groups (P>0.05). The activity of protease, lipase, and amylase, in the stomach and intestine significantly increased when the dietary Quercetin level was above 400 mg/kg. The malondialdehyde level, and total antioxidant capacity in the hepatopancreas of Quercetin diet groups decreased significantly while catalase activity of Quercetin diet groups (apart from the group fed 1600 mg/kg Quercetin) increased significantly (P<0.05) with no significant differences between all Quercetin groups. Superoxide dismutase activity was not affected by Quercetin supplementation. The results of the present study suggested that Quercetin supplementation in a tilapia diet could have beneficial effects on digestive enzyme activity, antioxidant potential in the hepatopancreas, and improve growth performance.
A comparative study of detection methods for Lactococcus garvieae in experimentally infected rainbow trout (Oncorhynchus mykiss, W.)
Authors: Ürkü Ç. , Timur G.
Published: February 2021

This study was carried out to detect Lactococcus garvieae from experimentally infected rainbow trout (Oncorhynchus mykiss, W.) using bacteriological, serological, and histopathological techniques. Rainbow trout were experimentally infected with two Lactococcus garvieae strains (L1 and L2) by intraperitonal injection. These strains caused bilateral exophthalmia with periocular hemorrhage, corneal opacification, darkening of the skin, strong internal congestion in the visceral organs, and enlargement of the spleen in the infected rainbow trout. The two L. garvieae strains were re-isolated from experimentally infected fish groups and identified with standard biochemical methods and API 20 STREP system. The presence of L. garvieae in the tissue of experimentally infected fish was confirmed by Indirect Fluorescent Antibody Technique (IFAT). The humoral antibody response of the infected fish was confirmed by slide agglutination, IFAT, and Enzyme Linked Immunosorbent Assay (ELISA). Histopathologically, liquefactive necrosis in the liver, spleen, and kidney, epithelial cells hyperplasia, hemorrhages and telangiectasia of the gill filaments, and sub-retinal hemorrhages in the eyes were observed.
Effect of Psidium guajava and Phyllanthus acidus Leaf Extract on Immunostimulant Response of Nile Tilapia Against Streptococcus agalactiae Infection
Authors: Kamble M.T. , Yakupitiyage A. , Salin K.R. , Chavan B.R.
Published: February 2021

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.
Padina caulescens and Schizochytrium sp. as Supplemented Feed in the Nursery Production of Penaeus vannamei Post Larvae Reared in Biofloc Systems
Authors: 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.
Published: February 2021

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.
Effects of Dietary Chromium Methionine on Growth Performance, Hematological Characteristics and Carbohydrate Metabolic Enzyme Activities of Common Carp (Cyprinus carpio)
Authors: Cui P , Yin S , Cheng Z , Qiao X , Zhou Q.
Published: February 2021

A 60-day feeding trial was conducted to evaluate the effects of dietary chromium methionine (Cr-Met) supplementation on growth performance, digestive enzymes, hematological characteristics, and carbohydrate metabolic key enzyme activities in juvenile common carp (Cyprinus carpio). Seven diets (32.2% crude protein, 6% crude lipids of dry matter) were formulated to contain graded levels of Cr3+ (0.31, 0.43, 0.57, 0.73, 1.13, 1.90 and 3.64 mg/kg, respectively). Each diet was randomly assigned to triplicate groups of 60 juvenile common carp (approximately 40.95±4.80 g), which were stocked in plastic tanks. The results indicated that the highest weight gain (WG), specific growth rate (SGR), feed efficiency (FE), and protein efficiency ratio (PER), were observed in fish fed the diet containing 1.13 mg/kg Cr3+. There were no significant differences in the wholebody compositions; however the glycogen levels in the muscle and hepatopancreas in fish fed the basal diet were lower than those fed the other diets. The insulin (INS) and glycogen (GC) concentrations in the serum were not significantly influenced by the dietary Cr-Met levels. However, fish fed the basal diet had higher glucose and cortisol concentrations, and lower insulin receptor (ISR) and LDH concentrations in the serum than those fed diets supplemented with Cr-Met. Fish fed the 1.13 mg/kg Cr3+ diet had significantly higher hexokinase (HK), 6-phosphofructo-1-kinase (6-PFK1), glucose-6-phosphate dehydrogenase (G6PDH), glycogen synthase (GS), and lower phosphoenolpyruvate carboxykinase (PEPCK) activities than those fed the basal diet. Based on the two-slope broken line model analysis between SGR and dietary Cr3+ levels, the optimal dietary Cr3+ supplement level was estimated to be 1.09 mg/kg for juvenile common carp.
Effect of Grape Seed Proanthocyanidins on Alleviating Dietary Cadmium (Cd) Induced Growth Retardation and Oxidative Stress in Hepatopancreas of Juvenile Tilapia (Oreochromis niloticus)
Authors: Zhai S-W. , Lu J-J. , Zhao P-Y. , Chen X-H.
Published: February 2021

This trial was conducted to evaluate grape seed proanthocyanidins (GSPs) on alleviating the effects of dietary cadmium (Cd) induced growth retardation and oxidative stress in hepatopancreas of juvenile tilapia (Oreochromis niloticus). Two hundred and forty fish were randomly divided into four groups with four replicates in each group and 15 fish in each replicate. The four groups were: control group (fed with a basal diet), Cd group (fed with a basal diet+100 Cd mg/kg), Cd+ GSPs group I (fed with a basal diet+100 mg Cd/kg+400 mg GSPs/kg), and Cd+ GSPs group II (fed with a basal diet+100 mg Cd/kg+800 mg GSPs/kg). The trial period was 49 days. Final body weight and weight gain rate of Cd group were significantly affected (P<0.05) compared with the control group. There was a significant difference in final body weight, weight gain rate, and feed conversion rate between the Cd (control) group and the two GSPs groups (P<0.05). Feeding rate and survival rate of all groups was similar (P>0.05). Levels of malondialdehyde, glutathione, and total antioxidation capacity and activities of superoxide dismutase, catalase, and glutathione peroxidase in hepatopancreas of the Cd group were affected significantly (P<0.05). No significant differences in malondialdehyde level and antioxidant potential parameters (except glutathione peroxidase in Cd+GSPs group II) were found between control group and all GSPs supplemented groups (P>0.05). Results indicate that dietary GSPs supplementation may alleviate dietary Cd-induced growth retardation and oxidative stress in hepatopancreas of tilapia.
Identification and mRNA Expression of Heat Shock Proteins in the Mud Crab (Scylla paramamosain) in Response to Acute Nitrite Exposure
Authors: Cheng C-H. , Ma H-L. , Feng J. , Su Y-L. , Deng Y-Q. , Chen X.-L. , Guo Z-X.
Published: February 2021

Heat shock proteins (HSPs) play an important role in protecting organisms against various stressors. Heat shock protein 40 (HSP40) is a class of the heat shock protein family and performs a function as co-chaperone of HSP70. In this study, an HSP40 gene from the mud crab Scylla paramamosain (SpHSP40) was identified and characterized. The full-length cDNA of SpHSP40 was 1904 bp, containing an open reading frame (ORF) of 1191 bp, a 5´UTR of 118 bp, and a 3´UTR of 595 bp. The deduced amino acid sequence of SpHSP40 contained all four classical HSP40 family signatures. Quantitative real-time PCR analysis revealed that SpHSP40 transcript was expressed in a wide range of tissues, while strong expression was observed in the hepatopancreas. In order to understand the response of heat shock proteins induced by nitrite exposure, expression levels of HSPs (SpHSP90, SpHSP70, SpHSP60 and SpHSP40) mRNA in the hepatopancreas and gills were investigated. Results show that HSPs (SpHSP90, SpHSP70, SpHSP60 and SpHSP40) were up-regulated displaying a time-dependent pattern in response to nitrite stress. All these results indicate that HSPs play an important role in mediating environmental stress in mud crabs.
Recovery of Listonella anguillarum from Diseased Pufferfish (Takifugu rubripes) in China
Authors: Sun H. , Luo Z. , Zhang Z. , Hao S. , Ding S.
Published: February 2021

In May 2016, there was a disease outbreak among pufferfish (Takifugu

rubripes) in a marine farm in Tianjin municipality, with the cumulative

mortality rate reaching 45% within 7 days from the beginning of the

outbreak. The main symptoms of the disease were abdominal and anal

swelling of the diseased fish. Significant damage was also observed

histopathologically in the intestine, liver, and kidney. The strain H008 was

isolated from diseased kidneys, and the challenge test revealed that the same

disease was diagnosed in pufferfish which suffered similarly high mortality

rates. Using physiological biochemical tests combined with 16S rDNA

sequence analysis, the strain was identified as Listonella anguillarum.

Antimicrobial susceptibility tests showed that H008 was resistant to 10 of 15

antimicrobial agents tested. To the best of our knowledge, this is the first

report of L. anguillarum causing disease in pufferfish.
A Review: Factors Affecting Outbreaks of Saprolegniosis on Aquatic Animals
Authors: Yang S , Chen D. , Ou Y. , Deng Y. , Geng Y. , Wang K. , Feng Y. Huang , Duan J.
Published: February 2021

In this paper, we review the current knowledge regarding factors affecting the

outbreaks of saprolegniosis. Saprolegniosis is a serious disease which can

cause significant economic losses in aquaculture. Oomycetes are considered

to be responsible for the disease. Outbreaks of saprolegniosis occur when

equilibrium between pathogenic oomycetes and host resistance is disturbed.

This may be the result of an increase in numbers or virulence of the zoospores

of oomycetes in the water, or an increase in the susceptibility of the host. The

presence of oomycetes zoospores in the environment is regarded as one of

the most important causes of saprolegniosis. However, important differences

have been found between plant and animal pathogenic oomycetes and appear

to be related not only to tactic responses to environment, but also to infection

strategies to a host. In addition, fish are more susceptible to infection by

pathogenic oomycetes when physically injured, stressed or infected.

Furthermore, water environmental factors, such as temperature, salinity, and

microorganisms, should be carefully considered since they play a key role in

the outbreaks of saprolegniosis.
Effect of Dietary Supplementation of Glycyrrhetinic Acid and Tea Polyphenols on Depuration of 2-methylisoborneol from Blunt Snout Bream, Megalobrama amblycephala
Authors: Guangzhen Jiang , Dongsen Cai , Dingdong Zhang , Xiangfei Li , Wenbin Liu
Published: February 2021

Abstract_Off-flavor is a serious issue in cultured fish. It affects marketability and texture of fish and

causes great economic losses in the aquaculture industry. Holding fish in a clean-water

environment for some time is an effective method to depurate them although it involves

weight loss. This study investigates the potential effects of dietary supplementation of

glycyrrhetinic acid (GA) and tea polyphenols (TP) on the depuration of the strong odors of 2-

methylisoborneol (MIB) from blunt snout bream, Megalobrama amblycephala. 560 fish, initial

average weight of 48.75±0.48 g were distributed into 28 tanks at a rate of 20 fish per tank.

Three diets, namely the control diet, a GA supplemented diet (0.3 g/kg), and a (TP)

supplemented diet (0.3 g/kg) were used in this study. The control diet was randomly assigned

to 20 tanks, 4 tanks with clean water (control), or with water containing 1μg/L MIB. During the

first 28-day the fish in each treatment were hand-fed to apparent satiation three times daily.

In the second phase (29-42 day), the control, GA, and TP treatments were divided into four

groups: MIB, low density (LD), high density (HD), and dynamic sampling (DS) with twenty fish

in DS, and fifteen fish in the others. Fish in LD, HD, and DS in all treatments were starved in

clean water. Fish in the DS treatment were sampled at 0, 24, 48, 72 hours, at 7 and 14 days.

No differences were observed in body weights between groups within the 28-day feeding trial

(P>0.05). Fish in GA, LD, and HD groups had significantly lower hepatosomatic index (HSI)

and intraperitoneal fat ratios (IPF) than the control, MIB, and TP groups (P<0.05). After 28

and 42 days, fish in the MIB group had higher MIB concentrations than the other groups

(P<0.05). Scores of sensory characteristics were similar, with no statistical differences

between the control, GA, and TP groups (P>0.05). MIB content decreased significantly in

relation to longer depuration times (P<0.05). Fish weight in LD and HD treatments declined by

10% and 12% respectively after 14-day fasting. In conclusion, clean water depuration for

fourteen days is an effective method to purge off-flavored flesh although it involves weight loss

and dietary supplementation of GA and TP which also depurate MIB from flesh of Megalobrama

amblycephala.
Effects of Salinity Fluctuation on Gene Expression Profiles of Female Litopenaeus vannamei Broodstocks
Authors: Zhang M. , Huang X-K , Hu L-H. , Ji D.W. , Tang M , Li F. , Luo K. , Zhang J.M. , Chai X.L. , Yan M.C.
Published: February 2021

In this study, the effects of salinity fluctuation on gene expression patterns in ovary and hepatopancreas of Litopenaeus vannamei were analyzed. The expression level of vitellogenin in the ovaries were significantly, markedly, and slightly, inhibited respectively in the hepatopancreas after brooders were transferred from 30‰ to 20‰ or 40‰ salinity for 4 days. The expression levels of the development of germ cell related genes Dmc1, proliferating cell nuclear antigen (PCNA) and cyclophilin A were significantly reduced at 20‰ or 40‰ salinity. The transcript level of shrimp ovarian peritrophin (SOP) was significantly reduced at 20‰ salinity, and the expression level of ovary specific gene mucin-5 AC was significantly higher at 40‰ salinity. Four stress related genes, cytoplasmic carbonic anhydrase (LvCAc), Na+/K+-ATPase alpha subunit (LvNK), V-H+-ATPase subunit A (LvVH), and heat shock protein 90 (LvHSP90), were significantly up-regulated at 40‰ salinity in the ovaries. In the hepatopancreas, the transcript level of fatty acid synthase (LvFAS) was significantly inhibited under 40‰ salinity. The mRNA levels of stress related genes LvNK, LvVH, and LvHSP90, were significantly lower at 40‰ salinity. Results indicated that changes in salinity caused transcription inhibition of germ cell and ovarian development related genes, and the expression patterns of stress related genes in the ovaries and hepatopancreas were quite different.
Two Rapid Methods to Identify Three Species of Pathogenic Vibrio in Penaeus vannamei
Authors: Luo K. , Yuan H. , Zhang W. , Xu Q.
Published: February 2021

Vibrio species frequently infect Penaeus vannamei causing great economic losses to the

Whiteleg shrimp industry. Rapid detection of pathogenic Vibrio infection would improve

the fight against these diseases. In this study, single and multiple polymerase chain

reaction (PCR) methods were developed to detect three species of pathogenic Vibrio:

Vibrio fluvialis, Vibrio anguillarum, and Vibrio alginolyticus. Specific primers were

designed for the toxR gene of V. fluvialis, the flaA gene of V. anguillarum, and the pyrH

gene of V. alginolyticus. The bacteria were used as templates to establish a 25 μL

reaction system for PCR amplification. The results showed that single and specific PCR

amplification products of expected sizes were obtained (228bp, 1665bp, and 383bp,

respectively). The lowest concentration detected for the three Vibrio species were

5.21×102

, 2.70×104

, and 2.48×102 colony forming units (cfu)/mL, respectively. We also

developed a multiplex PCR method to identify the three Vibrio species accurately, and

with improved identification efficiency. In addition, quantitative real-time PCR (qPCR)

was used to identify the minimum detectable DNA concentration for the three Vibrio

species (1.0×10-6 nmol/L for V. fluvialis, 1.0×10-7 nmol/L for V. anguillarum, and 1.0×10-

8 nmol/L for V. alginolyticus). Technical requirements for ordinary PCR are low, therefore

PCR is a feasible technique to detect and diagnose Penaeus vannamei bacterial disease.
Identification and mRNA Expression of Antioxidant Enzyme Genes in the Mud Crab (Scylla paramamosain) in Response to Acute Ammonia and Nitrite Exposure
Authors: Cheng C-H , Ma H.-L. , Feng J. , Su Y-L. , Deng Y-Q. , Peng J-H. , Guo Z-X
Published: February 2021

Thioredoxin reductase (TrxR) is a conserved protein that is involved in protecting organisms against various oxidative stresses. In this study, a thioredoxin reductase gene was cloned from the mud crab Scylla paramamosain (SpTrxR). The full-length cDNA of SpTrxR is comprised of 2724 bp with a 1791 bp open reading frame that encodes a putative protein of 596 amino acids. The deduced amino acid sequence of SpTrxR contains the typical TrxR domain. Quantitative real-time PCR analysis revealed that the SpTrxR mRNA was distributed abundantly in mud crabs, while strong expression was observed mainly in the gills. The expression of antioxidant enzyme genes (SpTrxR, SpTrx, SpSOD, and SpCAT) was measured using quantitative real-time PCR after acute ammonia and nitrite exposure. The results show that antioxidant enzyme genes (SpTrxR, SpTrx, SpSOD, and SpCAT) were modulated by acute ammonia and nitrite exposure. These results suggest that antioxidant enzyme genes play an important role in protecting organisms against oxidative stress
Effects of Formulated Diet Co-fed with Minced Fish on Growth, Digestion, Metabolism, and Appetite Regulation, of Mandarin Fish Hybrid (Siniperca chuatsi ♀× Siniperca scherzeri ♂)
Authors: Li Y. , Li Y , Xu Q.
Published: February 2021

This study examined the effects of a formulated diet combined with minced fish at ratios of 1:1 (Diet 1), 1:3 (Diet 2) and 0:1 (Diet 3) on growth, digestion, metabolism, and appetite of juvenile mandarin fish (initial weight, 10.63 ± 0.29 g). Fish were hand fed to satiation for 194 days. Weight and growth rate of the fish in the first 97 days were negatively correlated to decreased ratio of minced fish. The weight of fish fed Diet 2 (97 days) was significantly higher than that of fish fed Diet 1. There was no significant difference in the growth of fish fed Diets 2 or 3. The activities of pepsin in the stomach, alanine transminase (ALT), and aspartate transminase (AST) in the liver, significantly increased in relation to the enhanced formulated diet ratio. The mRNA level of leptin in the liver and ghrelin in the stomach increased as the minced fish ratio decreased. The mRNA level of neuropeptide Y (NPY) in the brain increased as formulated diet ratios increased. Combined feeding strategies increased the appetite of the mandarin fish hybrid, improved digestion and metabolism of formulated diets, and improved fish growth.
Fermented Sweet Potato Meal, a Sustainable Dietary Protein Ingredient for Juvenile Penaeus vannamei, Boone 1931.
Authors: Traifalgar R. F. , Pagapulan J. , Valdez M. T. , Ellamar J. B. , Ocampo E. J. C. , Ilag L. L.
Published: February 2021

Fermentation-biotechnology to produce high-protein agricultural biomass with potential as a feed ingredient is well-established. However, practical applicability of this technology in aquaculture has not been fully realized. The present work evaluates the nutritional and feed value of fermented sweet potato meal (ProEn-KTM) to replace soybean meal in the diet of juvenile Penaeus vannamei. Four experimental diets containing graded levels of ProEn- KTM replacing 0 (%), 25 (%), 50 (%) and 100 (%) of soybean meal were formulated and fed to P. vannamei for 8 weeks. Results showed that 100 (%) of soybean meal can be replaced by fermented sweet potato and 50 (%) replacement elicited growth promoting effects. Survival, feed conversion, and body composition were similar in all treatments. Dietary inclusion of fermented sweet potato promotes better ratio of the n-3/n-6 fatty acid and lowers the total gut bacteria as well as total Vibrio. Collectively these results suggest that fermented sweet potato meal could fully replace soybean meal in P. vannamei diet. The use of this feed ingredient is a practical approach to meet the increasing needs of proteins in feeds for the expansion and sustainability of P. vannamei aquaculture.
Effects of Dietary Niacin on Growth Performance, Serum Biochemistry, Antioxidant Ability of Liver, Intestinal Digestion, and Absorption in Juvenile Golden Pompano
Authors: Xun P , Lin H. , Wang R , Huang Z , Zhou C , Yu W , Huang Q , Yang Y , Huang X , Tan L , Yu W
Published: February 2021

Six groups of experimental diets containing different levels (14.9, 22.4, 28.6, 37.9, 42.0 and 77.5 mg/kg) of niacin were formulated. Juvenile golden pompano (initial body weight:7.82±0.07 g) were fed in cages for eight weeks. Results showed that moderate niacin in the diet significantly increased (P<0.05) weight gain rate (WGR), specific growth rate (SGR), and feed efficiency (FER). Dietary niacin levels increased the protein content in whole fish and muscle (P < 0.05). The content of serum high density lipoprotein cholesterol (HDL-C) and total cholesterol (TCHO) increased significantly and triglyceride (TG) content decreased significantly (P<0.05). C3 and C4 content in serum, and activities of lysozyme (LZM), and alkaline phosphatase (ALP) increased significantly (P<0.05). Dietary niacin levels significantly increased (P<0. 05) the catalase (CAT), alkaline phosphatase (ALP), and total antioxidant capacity (T-AOC) of the liver when niacin content was more than 28.6 mg/kg. Dietary niacin levels also improved intestinal digestion and absorption by increasing glutamyl transferase (γ-GT)activity. Quadratic regression analysis on WGR indicated that the optimum dietary niacin level for optimal growth of juvenile golden pompano was 29.85 mg/kg.
Eyestalk Ablation, a Prerequisite for Crustacean Reproduction: A review
Authors: Chan S. , Wang W. , Shi L. , Liu J. , Zhou T. , Wang C. , Amankwah B.K
Published: February 2021

Reproduction in crustaceans is a process which demands critical study in order to help improve productivity in aquaculture. In recent years, many studies have been geared towards studying how eyestalk ablation affects the reproduction of crustaceans. This review highlights many of the various neuroendocrine groups found in the crustacean eyestalks, their importance, and their contribution to crustacean reproduction. This review also provides a description of the eyestalk, eyestalk ablation, and how it affects crustacean reproduction. Conclusions and perspectives have also been made to aid further studies.
Effects of Dietary Pantothenic Acid Supplement on Hepatic Antioxidative Abilities and Intestinal Microflora in Juvenile Golden Pompano (Trachinotus Ovatus)
Authors: Xun P. , Lin H. , Zhou C. , Huang Z. , Yu W. , Yang Y. , Huang X. , Wang Y. , Huang Q. , Tan L.
Published: February 2021

This study explored the effects of dietary pantothenic acid (PA) supplement on juvenile golden pompano (Trachinotus ovatus). Six isonitrogenous and isolipidic diets containing six graded levels of pantothenic acid (0, 16.4, 20.0, 26.0, 33.4 and 37.0 mg/kg) were formulated. Juvenile golden pompano (8.80±0.10g) were randomly assigned into six groups with three replicates in each group and 20 fish in each replicate. The fish were fed twice a day for 8 weeks. The results indicated that PA deficiency caused clubbed gills with interlamellar proliferative lesions. Survival rate increased significantly (P＜0.05) when PA levels were increased. Dietary PA significantly increased the activities of hepatic acid phosphatase (ACP), alkaline phosphatase (ALP), peroxidase (POD) and glutathione reductase (GR) (P＜0.05) and their activities reached the maximum in the Diet-P4 group. A diet supplemented with 20.0 and 26.0 mg/kg PA significantly decreased (P＜0.05) the activity of hepatic MDA. Dietary PA also increased the diversity and abundance of intestinal microflora and inhibited the growth of harmful bacteria. In conclusion, PA deficiency caused lesions of gills and optimal PA supplement in diet increased hepatic antioxidative abilities and improved intestinal microflora of juvenile golden pompano.
Pathogenicity and Immune Response of Starry Flounder, Platichthys stellatus, Infected with Vibrio anguillarum
Authors: Jang Y.H. , Dharaneedharan S. , Kim D–H. , Yoo E-H. , Kang B.J. , Heo M-S.
Published: February 2021

Vibrio anguillarum is the aetiological agent of vibriosis, a disease affecting many marine fish species. The occurrence of vibriosis in starry flounder, Platichthys stellatus, grown in an aquaculture farm has demonstrated the urgent need for information on pathogenic infection and immune response for efficient disease management. This is the first study to report Vibrio anguillarum isolation and infection in starry flounder. We evaluated immune responses, serum biochemical parameters, and cumulative mortality of the fish by experimentally challenging healthy fish. The expression levels of five immune genes (TNF, TNFR, IL-6, MHCII, and CXC) were measured by real-time quantitative PCR. The transcriptional levels of the genes encoding tumor necrosis factor (TNF), TNF receptor (TNFR), interleukin-6 (IL-6), the major histocompatibility complex (MHC-II), and a chemokine (CXC) in the head-kidney of V. anguillarum infected fish were significantly upregulated compared with control fish and biochemical indices including the alanine aminotransferase, total serum protein, and glucose levels of infected fish differed significantly from those of control. Additionally, Starry flounder infected with V. anguillarum at 1.67 × 106 and 1.67 × 108CFU/mL showed 53%, and 100% mortality, respectively. This study furthers our understanding of the immune and serum biochemical alterations, and mortality induced by bacterial infections, depending on pathogen concentration. This may advance strategies for control of V. anguillarum in cultured starry flounder
Salinity Effect on Intestinal Microbiota in Golden Pompano Trachinotus Ovatus (Linnaeus, 1758)
Authors: Liu Bo , Guo H. , Zhu K. , Guo L. , Liu B. , Zhang N. , Jiang S. , Zhang D.
Published: February 2021

Golden pompano (Trachinotus ovatus) is a commercially important marine fish which is widely cultured in the coastal area of South China. Salinity is one of the most important environmental factors influencing the intestinal microbiota. The aim of this study was to investigate the intestinal microbiota of juvenile golden pompano reared at different salinities. In this 56 day experiment, juveniles were reared at 5, 15, 25 and 35‰ salinities. Based on ACE, Chao1 and Shannon, Simpson diversity indices, salinity did not influence the bacterial richness and diversity in golden pompano intestine. The data indicated that the dominant phyla in golden pompano intestine reared at each salinity group were Proteobacteria. The principal coordinates analysis (PCoA) indicated that the bacterial communities were not clustered, and the bacterial communities were very different in the salinity groups. The findings showed that golden pompano have specific intestinal microbiota in different salinity environments. However, the intestinal microbiota in golden pompano were strongly influenced by salinity and were also affected by the phylogeny of golden pompano. Further studies are needed to explore the relationship between the intestinal microbiota and growth of golden pompano under different salinities
The Effect of Water Temperature on Antioxidant and Digestive Flexibility in Miiuy croaker, Miichthys miiuy
Authors: Liu F. , Wang M. , Chu T. , Zhan W. , Lou B.
Published: February 2021

Miichthys miiuy is a marine fish with high commercial value that is extensively cultured in China. Seawater temperature is an important factor that affects the cultivation of this fish. However, whether and how seawater temperature affects enzymatic activity during cultivation remains unclear. We treated M. miiuy with average body weight of 232.59 ± 48.79 g with four seawater temperature treatments (13.0, 20.0, 24.0, and 30.0 °C) for 12 days, and measured activities of liver antioxidant enzymes (SOD and CAT) and intestine digestive enzyme (lipases, amylase, and trypsin) at the beginning and end of the treatment. Temperature had a significant effect on the activity levels of antioxidant enzymes. SOD activity decreased from 13.0°C to 24.0°C, and increased at 30.0°C, where SOD activity was highest in samples placed in 30.0°C seawater, and lowest at 24.0°C. There were no clear trends in the CAT activity pattern with increasing temperature, and highest CAT activity levels were observed at 20.0°C and lowest levels were observed at 24.0°C. The activity rates of digestive enzymes were also significantly affected by temperature. However, there were no clear trends in activity pattern with increasing temperature, similar to CAT. Lipase activity was highest at 24.0°C, and amylase activity was highest at 24.0°C. Trypsin activity was similar across the different temperature treatments after 12 days of culturing. The present study investigated the effects of seawater temperature over time on the activities of antioxidant and digestive enzymes in M. miiuy, and the results will help develop better culture practices for M. miiuy.
Growth Performance, Lipid Deposition and Serum Biochemistry in Golden Pompano Trachinotus Ovatus (Linnaeus, 1758) Fed Diets with Various Fish Oil Substitutes
Authors: Xiuling L. , Baosuo L. , Bo L. , Nan Z. , Liang G. , Kecheng Z. , Huayang G. , Shigui J. , Dian C.Z.
Published: February 2021

In this study, 640 golden pompano (mean initial weight of 82.85±2.36 g) were randomly allocated into 32 floating net cages. Eight experimental diets involving various lipid sources were given. They were: fish oil (FO), krill oil (KO), soybean oil (SO), corn oil (CO), 1:1 FO-SO, 1:1 FO-CO, 1:1 KO-SO and 1:1 KO-CO. The results showed that the specific growth rate in the SO, CO, 1:1 FO-SO and 1:1 KO-SO groups was significantly lower than in the FO group (P<0.05), and the 1:1 KO-CO had lower feed conversion ratio (FCR) among all the diets. The muscle fatty acid compositions were closely correlated with the fatty acid composition of the diets. Moreover, the serum MDA content of golden pompano fed the other seven diets was significantly lower than that of the fish fed the FO diet (P<0.05) except for the 1:1KO-CO diet, with the lowest MDA content, which occurred in KO diet. Accordingly, we concluded that the FO, KO, 1:1 FO-SO and 1:1 KO-CO diets resulted in improvements in growth performance in golden pompano. Moreover, KO diet regulated some physiological and biochemical indicators. This study could provide a basis for the response-based selection of optimal lipid sources.
Isolation and Characterization of Polymorphic Microsatellites from Draft Genome Data for Large Yellow Croaker, Pseudosciaena Crocea
Authors: Li-qin L. , Yao Z. , Xiao-yu H. , Zhen-ming L. , Li G.
Published: February 2021

In this study, we isolated thirty-eight microsatellite loci from the draft genome of large yellow croaker, Pseudosciaena crocea. These loci were tested on 34 individuals from Zhangzhou prefecture city in Fujian. Most loci were highly polymorphic. A total of 214 alleles were detected with an average of 5.63 alleles per locus. The observed and expected heterozygosity ranged from 0.454 to 0.909 and from 0.503 to 0.918, with an average of 0.635 and 0.744, respectively. The PIC values of these loci ranged from 0.372 to 0.878, with an average of 0.712. Eight loci significantly deviated from Hardy-Weinberg equilibrium (HWE). Significant linkage disequilibrium (LD) was not found in these 38 loci. The newly identified polymorphic markers will contribute to the study of genetic diversity, population structure, and conservation of P. crocea.
Research progress on the cannibalistic behavior of Aquatic Animals and The Screening of Cannibalism-Preventing Shelters (Review)
Authors: He Jie , Shi Hui , Xu Wenjun , Su Zhixing
Published: February 2021

The aim of this 42-day study was to examine the effects of Chlorella vulgaris on immuno-related factors and their expression in Penaeus vannamei. Results showed that C. vulgaris significantly enhanced the activities of phenolic oxidase (PO), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in the serum and hepatopancreas of P. vannamei (p<0.05, p<0.01), increased the expression levels of PO, SOD, GSH-Px, CAT, and IMD genes in the serum of P. vannamei (p<0.05, p<0.01), and significantly increased the expression level of Toll receptor genes in the hepatopancreas of P. vannamei (p<0.05, p<0.01) and the expression level of IMD gene. In conclusion, C. vulgaris regulated the immune function of P. vannamei through the Toll receptor gene and the IMD pathways. We speculated the Chorella polysaccharides were the main active ingredients of C. vulgaris
Dietary Protein Requirement of Juvenile Ide, Leuciscus idus in Relation to Growth Performance, Whole-body Composition and Plasma Parameters
Authors: Ge Xianping , Ren Mingchun , Ji Ke , Liang Hualiang , Mi Haifeng
Published: February 2021

A 60-day feeding trial was conducted to determine the dietary protein requirements of juvenile ide, Leuciscus idus. Six iso-energetic experimental diets were formulated to contain graded protein levels ranging from 26.5% to 50.9% of dry diet. At the end of feeding trial, final weight (FW), weight gain (WG), and specific growth rate (SGR) increased significantly with increasing dietary protein levels up to 36.4%, and thereafter decreased with further increase of dietary protein levels (P<0.05). Feed conversion ratio (FCR) showed a converse trend (P<0.05). Hepatosomatic index and viscerosomatic index were negatively related to dietary protein levels (P<0.05). Increase of dietary protein levels significantly improved whole-body protein content and decreased lipid content (P<0.05). White blood cell counts, red blood cell, hemoglobin, and hematocrit, were independent of dietary protein levels (P>0.05). Plasma protein content was not significantly affected by dietary protein levels (P>0.05), while plasma triglyceride and glucose concentrations were decreased significantly with increasing dietary protein levels (P<0.05). The highest aspartic transaminase activity was observed in fish fed diet 26.5% protein, and the lowest value was observed in 36.4% protein group (P<0.05). Based on SGR and FCR, the dietary protein requirement of juvenile ide was determined to be 36.9%-37.7% of dry diet. Dietary methionine and lysine levels for optimal growth was calculated to be 0.83% and 2.25% of dry diet, respectively.
Gender Differences in Perceiving Advertising Texts
Authors: Arakelyan Rouzanna , Sahakyan Margarita
Published: February 2021

The concept of gender is one of the underlying means of creating effective advertising texts. The gender belonging, which ensures the impact and perception of ads, is conditioned by its thematic, linguo-stylistic and grammar characteristics. Certain gender belonging in a text can be indicated both directly and indirectly based on the stereotypes in the given culture. The firmer and more established the image about the social, psychological and biological characteristics of a certain interlocuter is, the more meaningful and impressive the information becomes. An advertising text is called effective and leads to some action if it takes into consideration the rules of speech impact and perception, as well as their relation to gender.
On Semantic Patterns of “Kill–Verbs” in Modern English
Authors: Khachatryan Robert
Published: February 2021

The article aims to reveal the semantic structures of the causative verbs in modern English, particularly with reference to the characteristics of the verbs meaning “to kill” and the way of expressing the main meaning of “to cause to die”. More precisely, the present article highlights the semantic features of these verbs that condition their causative nature. The article focuses on the investigation of only those verbs meaning “to cause to die” that are more frequent in speech, particularly the verbs to kill, to murder, to assassinate, to execute and to massacre. The linguistic data are borrowed from the British National Corpus.
Functional-Communicative Study of Adversative and Causal Discourse Markers
Authors: Khandanyan Siranush , Mardoyan Liza
Published: February 2021

The present article highlights the main problems related to the functional-communicative study and causal discourse markers. Both markers are widely applied in English textual and communicative discourses. The functional-communicative nature of the markers has been examined with reference to dialogues and monologues in fiction. The latter make it possible to clarify the importance of the adversative and causal discourse markers in the organization of the overall discourse. A number of features typical of both adversative and causal markers are revealed due to the context. In case of heavy dependence on the context, the markers do not perform a wide communicative function, for example in monologues, whereas in dialogues the role of the communicative function is enhanced.
The Role of the Article in the Semantic Interpretation of the Antecedent in Attributive Clauses
Authors: Hayrapetyan Nune
Published: February 2021

The role of the article in all grammar structures leaves no doubt. Attributive clauses prove no exception. Here, the article used with the antecedent contributes to the distinction of the attributive clause. Attributive clauses can be divisible and non-divisible. The antecedent of the latter is closely connected to the thematic continuation which acts as its characterization and does not need any restriction in the use of the article, i.e. both definite and indefinite article may be used here. Unlike non-divisible sentences, the antecedent in divisible attributive clauses is not strongly bound with its subordinate continuation since the latter contains additional information only. The semantic emphasis of the antecedent requires the use of only the definite article which can be used in zero category as an antecedent used in the presence of proper nouns.
Modal Adverbs Used as Hedges in Research Articles
Authors: Martirosyan Naira , Ghazaryan Tatev
Published: February 2021

The major aim of the author of a scientific text is to introduce his/her opinion as convincingly as possible trying to make an impact on the reader. Since it is not possible to ensure a direct connection between the reader and the author in written speech, it is necessary to create a field of a dialogue where certain words denoting conviction, uncertainty, indecisiveness and approximation are often used to qualify the information. In this regard, modal words are of special interest.