bluuebunny/crossref_metadata_2025 huggingface dataset:
Interaction of Gut Flora and Bacterial Pathogens of Cultured Common Dentex (Dentex dentex)
Authors: AKAYLI Tülay , ERKAN Melike , YARDIMCI Remziye Eda , ÇANAK Özgür , ÜRKÜ Çiğdem
Published: February 2021

This study was carried out to determine the population of gut flora and investigate the source of the pathogenic bacteria recovered from moribund dentex (Dentex dentex). Transmission electron microscopy (TEM) was used to monitor the translocation of bacterial pathogens which can enter the host through the gut. A total of 260 samples from larvae at different feeding stages were examined, 15 healthy and 50 moribund juvenile dentex were sampled over a 2-year period. Bacterial isolates (n=433) from healthy and moribund fish and their environments were identified by biochemical methods; 75% of them were identified as Gram-negative (mainly Vibrio spp.) and 25% as Gram-positive. Vibrio scophthalmi and other Vibrio species were recovered from moribund fish samples. Some bacteria were recovered from diseased fish reared in hatcheries, introduced mainly from sea water. Among anaerobic bacteria, Eubacterium tarantellae was recovered from larval gut flora while Clostridium botulinum was recovered from juvenile gut flora. TEM also showed that bacterial endocytosis first occurs when fish are fed granulated dry feeds and becomes more prevalent in the juvenile stages when many bacteria are present in the microvilli. TEM also revealed that the bacteria enter the larvae via the mouth and gills before the granulated feeding stage, after which they begin to penetrate the gut and finally also contaminate the marine rearing stage. The results of this study showed that the granulated feeding stage is critical for pathogen invasion in common dentex.
Protection of Litopenaeus vannamei against White Spot Syndrome Virus using bacterially expressed recombinant envelope proteins VP39 and VP28
Authors: Akhila Dharnappa S , Rai Praveen , Mani Madhu K , Ballamoole Krishna Kumar , Karunasagar Iddya , Karunasagar Indrani
Published: February 2021

White spot syndrome virus (WSSV) is a highly virulent shrimp pathogen, causing huge economic loss to the aquaculture industry. We investigated the efficacy of recombinant VP39 protein against WSSV infection in Litopenaeus vannamei by intramuscular and oral administration, and also compared the efficacy with recombinant VP28 (rVP28). The VP39 is a 283 amino acid protein encoded by the structural gene vp39 which acts as an important mediator for virus entry to the host. Shrimp orally vaccinated with rVP39 and rVP28 showed a cumulative mortality of 50% and 60% respectively following challenge, and this indicates that rVP39 had a better protective effect against WSSV infection compared with rVP28. Vaccination by intramuscular injection with rVP39 and rVP28 resulted in survival rate of 60% and 50%, respectively. The transcriptional profiling of viral genes of vaccinated shrimp with recombinant viral proteins of VP28 showed higher transcriptional levels than VP39. The transcriptional level of rVP39 vaccinated animals was delayed by 6 days after WSSV infection, while the delay was only 4 days in the case of rVP28. These results indicate that vaccination delays the transcription of envelope genes of WSSV in shrimp. The present study could demonstrate the importance of VP39 as a prominent candidate for vaccination against WSSV.
Effects of Dietary Corn Gluten Meal on Growth Performance and Cholesterol Metabolism in Juvenile Snakehead (Ophiocephalus argus) Fed Practical Diets
Authors: Yun Biao , Qian Xueqiao , Ai Qinghui , Xue Hua
Published: February 2021

An 8-week growth trial was conducted to investigate the effects of dietary corn gluten meal (CGM) levels on growth performance and cholesterol metabolism of juvenile snakehead (Ophiocephalus argus). Six isonitrogenous (crude protein 47%) and isolipidic (crude lipid 11.5%) practical diets were formulated by replacing 0 (D1, control), 6.2 (D2), 12.3 (D3), 18.5 (D4), 22.2 (D5), and 28.4% (D6) fish meal (FM) protein with CGM protein. No significant difference in survival rate was found among dietary treatments (P>0.05). No significant differences were observed in feed intake (FI), final body weight (FBW), weight gain rate (WGR), feed efficiency rate (FER) and protein productive value (PPV) among fish fed D1-D3 (P>0.05). However, these indices significantly decreased with increasing CGM protein from 18.5%(D4) to 28.4%(D6) of diet (P<0.05). Whole-body lipid content of fish fed D6 (28.4 %) was significantly lower than that of fish fed D1 (control) (P<0.05). The plasma and liver total cholesterol, free cholesterol, cholesterol esters, LDL-C, and HDL-C levels were affected by dietary CGM protein levels. Broken line analysis based on WGR or PPV indicated that the maximum CGM protein level for the optimal growth of juvenile snakehead was 12.06% or 12.56% respectively.
Aeromonas schubertii: a Potential Pathogen for Freshwater Cultured Whiteleg Shrimp, Penaeus vannamei
Authors: Cao Haipeng , Jian An , He Shan , Lu Liqun , Yang Xianle , Zheng Weidong
Published: February 2021

Bacteriosis has become a major global economic problem in freshwater farmed whiteleg shrimp Penaeus vannamei. However, limited information is available on the incidence of Aeromonas schubertii infections in freshwater cultured P. vannamei. Red body disease, an epidemic frequently associated with P. vannamei freshwater farming, occurred in a P. vannamei farm in Shanghai China in June 2013. A pathogenic strain of A. schubertii (isolate HS1) was isolated from diseased freshwater cultured P. vannamei suffering from red body disease, and identified through phylogenetic analysis and phenotypic characteristics. A phylogenetic tree was constructed to examine the relatedness of isolate HS1 with other A. schubertii isolates. In addition, isolate HS1 showed no signs developing antibiotic resistance when screened against a range of common antibiotics used in aquaculture. To the best of our knowledge, this is the first report of A. schubertii infection in freshwater farmed P. vannamei.
Effects of Different Dietary Lipid Sources on Spawning Performance, Egg and Larval Quality, and Egg Fatty Acid Composition in Tongue Sole Cynoglossus semilaevis
Authors: Xu Houguo , Lü Qingkai , Liang Mengqing , Zheng Keke
Published: February 2021

A 60-day feeding experiment was conducted to investigate the effects of dietary lipid sources on reproduction of Cynoglossus semilaevis. Experimental diets were formulated with similar proximate compositions but different lipid sources (6.5%): fish oil (FO), soybean oil (SO) and olive oil (OO). The results showed that the relative fecundity in group FO and OO was significantly higher than that in group SO. Group OO showed a significantly higher buoyant egg rate than group FO and SO. The hatching rate and larval survival rate at 7 days post hatching were the highest in group FO, followed by group OO, and group SO recorded the lowest values. Group FO showed significantly higher egg diameter and larval survival activity index (SAI) and significantly lower larval deformity rate compared to group SO and OO. Fatty acid compositions of eggs reflected closely those of the diets. These results showed that the olive oil supplement in diets for tongue sole positively influenced the broodstock fecundity and buoyant egg rate though fish oil resulted in the highest hatching rate and best larval quality among the tested oils. The dietary soybean oil supplement reduced the spawning performance, and egg and larval quality.
Vitrification of Common Carp (Cyprinus Carpio) Spermatozoa, Post-Thaw Sperm Quality, and Fertility
Authors: Bozkurt Yusuf , Yıldız Cengiz , Yavaş İlker
Published: February 2021

The aim of this investigation was to test a new technology, vitrification, or ultra-rapid freezing of the spermatozoa of common carp, and to study the ability of glucose, BSA, and other cryoprotectants to protect these cells from cryo-injuries. Spermatozoa were isolated and vitrified using 10 different cryoprotectant solutions: (1) Glucose based medium (GBM) + 1% bovine serum albumin (BSA); (2) GBM + 1% BSA + 10% DMSO; (3) GBM + 1% BSA + 20% DMSO; (4) GBM + 1% BSA + 30% DMSO; (5) GBM + 1% BSA + 10% DMA; (6) GBM + 1% BSA + 20% DMA; (7) GBM + 1% BSA + 30% DMA; (8) GBM + 1% BSA + 10% methanol; (9) GBM + 1% BSA + 20% methanol; (10) GBM + 1% BSA + 30% methanol. Fertilization rates for vitrification experiments were low and the use of low concentrations of cryoprotectants yielded lower fertilization rates than the vitrification solutions containing high cryoprotectant concentrations. In conclusion, this study reported successful vitrification of common carp spermatozoa by direct transfer into liquid nitrogen.
Effects of Mannan Oligosaccharide (MOS) on the Survival, Physiological, and Immunological Response of the Black Tiger Prawn (Penaeus monodon Fabricius, 1798) when Challenged with two Different Stressors
Authors: Sang Huynh Minh , Thuy Nguyen Thi Thanh
Published: February 2021

Two trials were conducted to determine the effects of mannan oligosaccharide (MOS) on the resistance of the black tiger prawn (Penaeus monodon) to two different stressors, bacterial infection by Vibrio alginolyticus, and the environmental pollutant ammonia (NH3). Prawns were fed two different diets, 0% (control diet) and 0.15% MOS, for 8 weeks prior to exposure to the stressors. They were then tested for survival, physiological, and immunological parameters, as indicators of health status. When the two groups were exposed to NH3 and bacterial infection, survival of prawns fed the MOS diet was significantly higher (P<0.05) than prawns fed the control diet. Similarly, the wet hepatosomatic index (Hiw), dry hepatosomatic index (Hid), hepatopancreatic moisture content (HM), total hemocyte count (THC), and granular cell percentage (GC%), of the MOS fed prawns was significantly higher (P<0.05) than in prawns fed the control diet. Bacteremia of the MOS fed prawns was lower (P<0.05) than the control diet-fed prawns after bacterial infection. Findings demonstrated the potential of MOS to improve the survival, health status, and immunity of black tiger prawns when challenged with bacterial infection and NH3 exposure.
Comparative Study of Antibacterial Properties of Emodin and Enrofloxacin Against Aeromonas hydrophila
Authors: Ren Mingchun , Chen Ruli , Zhou Qunlan , Pan Liangkun
Published: February 2021

Antibacterial properties of emodin, extracted from rhubarb, and enrofloxacin, against Aeromonas hydrophila, were assessed in this study. The minimum inhibitory concentration (MIC) values of emodin and enrofloxacin to fight A. hydrophila WJ2011BJ44 were found to be 100ug/ml and 9.375ug/ml, respectively. To understand the mechanisms of action of emodin and enrofloxcain against A. hydrophila we studied antibacterial activity, bacterial membrane permeability, and ultrastructure of A. hydrophila cells treated with emodin, enrofloxacin individually, and the combination of both. The results shown in the growth curve of A. hydrophila treated with different concentrations (from 0 MIC to 4 MIC) of emodin and enrofloxacin were similar and stable, and there was no significant difference in the growth curve of different treatment groups. There were significant differences in the K+ concentration among all treatment groups from 1 h to 8 h after incubation compared with the control. The highest K+ concentration was observed in the emodin+enrofloxacin group from 1 h to 8 h after incubation. PI fluorescence signal of untreated A. hydrophila cells and A. hydrophila cells treated with emodin, or enrofloxacin individually, or the combination of both were 0.89, 11.4, 13.98 and 18.3, respectively. The mortality of A. hydrophila cells treated with the combination of emodin and enrofloxacin was greatest compared with other groups. These results indicated that 2 MIC emodin, 2 MIC enroflxacin, and combination of 1 MIC emodin and 1 MIC enrofloxacin can inhibit the growth of A. hydrophila, increase bacterial membrane permeability, and damage cell membrane integrity. The combination of 1 MIC concentration emodin and 1 MIC concentration enrofloxacin produced the best antibacterial activity against A. hydrophila *
Chemical composition and fatty acid profile of Trans-Andean Shovelnose catfish Sorubim cuspicaudus
Authors: Prieto-Guevara Martha Janeth , Pájaro Cristina Morelo , Doria Yuly Yabrudy , Atencio-Garcia VictorJulio
Published: February 2021

Chemical composition and fatty acid profile were studied in larvae and adult Trans-Andean shovelnose catfish muscle. The chemical composition in dry matter of the larvae and the food they consumed were: moisture, 89.2%, 91.8%; protein, 79.8%, 70.6%; ethereal extract, 7.8% 7.2%; and ash, 12.7% and 14.5%, respectively. In adult muscle there were no significant differences between sexes in the percentages of moisture, protein, ethereal extract, and ash. Similarly, there was no statistical difference between sexes for monounsaturated fatty acids and polyunsaturated fatty acids. A significant difference between the sexes was found in the fatty acid profile which showed a predominance of saturated fatty acids. This study demonstrated that there is a great similarity in the chemical composition of the species. The percentage of protein and variation in ethereal extract and ash content was dependent upon the composition of its food. These results provide basic information for formulating adequate nutritional diets to meet the requirements of Neotropical fish.
The Effects of Fish Meal Replacement by Yeast Based Nucleotides on Growth, Body Composition and Digestive Enzyme Activity in Rainbow Trout Juveniles (Onchorchyncus mykiss)
Authors: Hunt Arzu Özlüer , Yılmaz Ferbal Özkan , Engin Kenan , Berköz Mehmet , Gündüz Suna Gül , Yalın Serap , Şahin Nefise Özlen
Published: February 2021

This 60 day study investigated the effects of organically certified nucleotide yeast-derived protein source (Nu-Pro®) on growth, feed efficiency, fillet proximate composition and digestive enzymes in rainbow trout (Onchorhyncus mykiss). Diets were isonitrogenous and isocaloric. Three experimental diets wherein 20%, 40% and 60% of the fish meal content was replaced by Nu-Pro®, were compared to the control diet in which the crude protein content was anchovy fish meal and corn gluten meal. The rainbow trout (initial weight 27 g/fish) were fed twice daily in 200-l Aqaria. Live weight gain increase ranged from 125-195% in fish fed the experimental diets. Results indicated that up to 40% fish meal protein can be replaced by Nu-Pro® without compromising growth rates, feed efficiency or the fillet biochemical composition in the rainbow trout. The effect of the dietary Nu-Pro® supplementation on digestion was partly observed by assaying the activity of pepsin, intestinal amylase, trypsin and lipase. Apart from amylase activity, results indicated that dietary supplementation of nucleotides is beneficial and may also have differential effects upon digestive enzyme activities.
Impact of Handling and Pre-Mortal Stress on the Flesh Quality of Common Carp (Cyprinus carpio L.)
Authors: Varga Dániel , Szabó András , Hanc Csaba , Jeney Zsigmond , Ardó László , Molnár Marcell , Molnár Tamás
Published: February 2021

The aim of this study was to investigate stress in common carp Cyprinus carpio L. caused by harvesting, transport, and the stunning method, and the effect of the latter on flesh quality Serum cortisol concentration increased during harvesting and transport. The percussive stunning (blow on head) method caused the least stress and resulted in a significant increase in blood cortisol concentration (P<0.01). This method had no significant effect on conventional flesh quality. CO2 asphyxiation which was more stressful delayed stiffening in rigor mortis development. The greatest stress was caused by live chilling. There was a decline of pH levels in the CO2 asphyxiated and live chilled groups compared to the percussive stunned group. According to our results percussive stunning led to the best fillet quality and is the least objectionable method according to animal welfare standards.
Sperm Properties of Waigieu seaperch (Psammoperca waigiensis)
Authors: Le Minh Hoang , Nhung Nguyen Thi Hong , Pham Linh Phuong
Published: February 2021

The aim of this study was to determine the semen properties of Waigieu seaperch (Psammoperca waigiensis). The physical properties of the semen were: semen volume 1.28±0.05 ml/fish, sperm density 31.35±0.67x109 cells/ml, spermatocrit 87.70±0.80%, and sperm count 40.12±1.68x109 cells/fish. The biochemical properties of the seminal plasma were 154.45±0.48 mmol/l sodium, 16.89±0.31 mmol/l potassium, 113.58±0.38 mmol/l chloride, 12.75±0.38 mmol/l calcium, 6.58±0.22 mmol/l magnesium, 1.15±0.08 g/l total protein, 346.37±2.71 mOsm/kg osmolality and 7.85±0.07 pH. Regression analysis showed a significant positive linear relationship between fish length and fish weight, sperm count and semen volume, and sperm density and spermatocrit, supporting the use of spermatocrit as a rapid estimator of sperm density in this species. Sperm motility parameters tested showed sperm motility, sperm velocity and duration of sperm motility as 95.80±0.389%, 144.50±0.96 µm/s and 232.30±2.32 s, respectively. The results from this study provide information on Waigieu seaperch sperm physiology. The values and correlations between the semen properties and the composition of seminal plasma may provide useful information for the formulating a species-specific extender solution for the cryopreservation of Waigieu seaperch sperm.
Preliminary Study on Hybridization of Brown Trout (Salmo trutta macrostigma) and Rainbow Trout (Oncorhynchus mykiss) Using Cryopreserved Sperm
Authors: Bozkurt Yusuf , Yavaş İlker
Published: February 2021

This study examined the effect of two different extenders (carbohydrate and mineral based), supplemented with 10% Dimethyl sulfoxide (DMSO), on cryopreservation of brown trout (Salmo trutta macrostigma) sperm used for hybridization with rainbow trout (Oncorhunchus mykiss). The carbohydrate based extender resulted in higher fertilization (42.5±1.4%) than the mineral based extender and there was no difference in fertilization rates (p>0.05). This study successfully demonstrated that it is possible to produce Salmo trutta macrostigma x Oncorhynchus mykiss hybrids using cryopreserved sperm from brown trout.
Isolation and Infectious Temperature Optimization of Genetically Similar VHSV Isolates in Farmed Olive Flounder, Paralichthys olivaceus
Authors: Jang Yeoung-Hwan , Dharaneedharan Subramanian , Kang Bong-Jo , Heo Moon-Soo
Published: February 2021

Viral hemorrhagic septicemia virus (VHSV) was isolated from farmed olive flounder (Paralichthys olivaceus). The viral N-gene was amplified by reverse transcriptase PCR, cloned, and sequenced for phylogenetic analysis to identify the genotype (I-IV). Virus isolates were cultured on Epithelioma papulosum cyprini cell line and, after completion of the cytopathic effects, the supernatant was collected and used to challenge virus-free flounder. The infected founder were reared in 16°C, 21°C, or 25°C, and compared to an unchallenged control. Virus titration was measured in the head kidneys, spleens, livers, brains, muscles, and gills of challenged fish using real-time quantification of the VHSV G-gene. Phylogenetic analysis confirmed that the isolates were VHSV Genogroup IV. The VHSV-challenged fish in the 16°C group showed 100% mortality with significantly increased expression of viral G-gene mRNA in the spleen, compared to fish reared in other temperatures and the control fish, suggesting that fish reared in 16°C are more susceptible to VHSV infection.
Dietary Histidine Requirement for Juvenile Large Yellow Croaker, Pseudosciaena crocea R.
Authors: Li Yan , Cheng Zhenyan , Mai Kangsen , Ai Qinghui , Shi ianhua
Published: February 2021

Dietary histidine requirements for large yellow croaker (initial average weight, 6.0 ± 0.10 g) were quantified by feeding isonitrogenous (crude protein 44%) and isocaloric (20 KJ/g) amino acid test diets with graded levels of histidine [0.45% (D1), 0.66% (D2), 0.78% (D3), 0.98% (D4), 1.24% (D5) and 1.40% (D6) of dry diet]. Each diet was randomly assigned to triplicate floating sea cages (1.0 × 1.0 × 1.5 m), 60 fish/cage. At the end of the 51 day experiment, the final weight (FW) and weight gain (WG) of large yellow croaker showed a positive correlation to increasing dietary histidine content (up to 0.78%), and thereafter declined. The growth of fish fed the D6 diet was significantly lower than fish maintained on the D2 and D3 diets; however, there were no significant differences in the growth of large yellow croaker among all the dietary treatments except D6. Fish fed the D3 diet had the highest FW and WG. The shift in feed efficiency (FE) values of fish fed D1 to D5 diets increased as dietary histidine content increased, and significantly decreased in fish fed the D6 diet. Based on the second-degree polynomial regression analyses of the growth data, optimum histidine requirement for juvenile large yellow croaker was 8.7 g/kg dry diet, (18.8 g/kg–20.8 g/kg of dietary protein within 95% confidence interval).
Effect of Citric Acid on Growth and Red Coloration of Red Porgy (Pagrus pagrus)
Authors: Chatzifotis Stavros , Martinez Lara Gomez
Published: February 2021

This study investigates the effect of dietary citric acid supplementation on the growth and red coloration of red porgy (Pagrus pagrus). Red porgy (~0.5 g) were fed one of four diets: (a) an unsupplemented control, (b) a diet containing astaxanthin at 0.06 g/kg, (c) a diet containing citric acid at 30 g/kg, or (d) a diet containing both astaxanthin at 0.06 g/kg and citric acid at 30 g/kg. After two months, fish reached ~6 g with no differences in growth between groups. Astaxanthin increased the total carotenoid concentration in the skin from 3.16 to 45.15 μg/g in fish fed the astaxanthin-supplemented diet and from 2.61 to 50.07 μg/g in fish fed the diet supplemented by both astaxanthin and citric acid, producing a distinctive red skin color. Diet composition did not affect the melanin concentration of the skin, which ranged 57.60-68.18 μg/g and did not differ between groups. Dietary supplementation of citric acid did not affect growth or coloration in red porgy, thus alternative means of administering citric acid should be sought, for example, adding citric acid to the rearing water or injecting it into the fish body.
Control by Herbal Extract of Serratia marcescens from Cultured Siberian Sturgeon Acipenser baerii Brandt
Authors: Cao Haipeng , Yang Yibin , He Shan , Zheng Weidong , Liu Kai , Yang Xianle
Published: February 2021

A virulent strain of Serratia marcescens, provisionally named SFY, was isolated from farmed Siberian sturgeon Acipenser baerii Brandt suffering from mouth-swelling disease and identified using the ATB 32GN system. Its taxonomic position was determined by phylogenetic analysis. A phylogenetic tree constructed using the neighbor-joining method showed that the SFY isolate was the S. marcescens strain (GenBank accession no. FJ530951). The strain was resistant to chloramphenicol, erythromycin, furazolidone, sulfamethoxydiazine, tetracycline, and trimethoprim-sulfamethoxazole, and susceptible to ciprofloxacin, enrofloxacin, gentamicin, neomycin, norfloxacin, ofloxacin, and streptomycin. Extracts from 30 Chinese herbs were screened as possible agents for control of the disease. Fructus mume extract was the most efficacious agent against the SFY isolate and control bacteria, indicated by its low minimum inhibitory concentration ≤21 mg/ml. At concentrations of 10 and 15 g/kg feed, protective efficacy was 42.68% and 64.64%.
Dietary Iron Requirement of Goldfish (Carassius auratus) Fry
Authors: Das Arabinda , Prakash Chandra , P.P Suresh Babu , Sharma Arun , Chanu Thongam Ibemcha , Paul Lokesh , Verma A.K.
Published: February 2021

To estimate the dietary iron requirement of common goldfish, Carassius auratus (Linnaeus, 1758), eight isoproteinous diets containing graded levels of dietary iron (FeSO4.7H2O) ranging 34.27-537.14 mg/kg were fed to triplicate groups of C. auratus fry in glass tanks. The rearing medium was groundwater passed through a reverse osmosis water treatment unit. Fish were fed 3% of their body weight per day. After 75 days, the fish were randomly sampled and anesthetized, blood was withdrawn from the caudal vein, and red blood cell count, hemoglobin content, and hematocrit value were evaluated. Tissue samples were randomly collected for muscle, liver, and whole-body iron analysis. The iron concentrations in the diets and fish tissues were measured by atomic absorption spectrophotometer. Broken-line regression analysis and analysis of variance (ANOVA) with multiple mean comparisons of the data indicate that the dietary iron requirement for optimal hematological values and tissue iron levels of C. auratus fry should be at least 139.06 mg/kg dry diet.
Effect of Different Antioxidants on Motility, Viability and Fertilizing Capacity of Cryopreserved Scaly Carp (Cyprinus carpio) Semen
Authors: Yavaş İlker , Bozkurt Yusuf , Yıldız Cengiz
Published: February 2021

The present study investigated the effect of different antioxidants such as taurine (25 mM, 50 mM, 75 mM and 100 mM), bovine serum albumine (BSA) (1%, 2.5%, 5%, 7.5%), and vitamin C (ascorbic acid) (2.8 mM, 5.6 mM, 8.4 mM and 11.2mM), on the motility and fertilizing ability of cryopreserved scaly carp (Cyprinus carpio) semen. The results demonstrated that addition of taurine at doses of 50 mM and 75 mM, and also BSA at doses of 2.5% and 5%, improved fertilization ability of cryopreserved scaly carp semen. The highest post-thaw motility (42.4±1.5%), viability (67.8±2.6%), fertilization rate (59.3±0.5%), and also hatching rates (68.2±3.4%) were determined by supplementation of 75 mM taurine (p<0.05). These results suggest that supplementation of ionic extender with taurine is suitable for scaly carp semen cryopreservation.
Effects of Dietary Soy Protein Concentrate on Growth Performance, Digestion, and Protein Metabolism of Juvenile Darkbarbel Catfish Pelteobagrus vachelli
Authors: Yang Yinghao , Ai Qinghui , Mai Kangsen , Xu Wei , Zhang Wenbing , Wang Xiaojie , Xue Jipeng
Published: February 2021

A 10-week feeding trial in a recirculation rearing system was conducted to investigate the effects of dietary soy protein concentrate (SPC) levels on survival, growth, digestion, and protein metabolism of juvenile darkbarbel catfish Pelteobagrus vachelli. The results demonstrated that survival and whole-body composition were independent of dietary treatments. Feed intake (FI), specific growth rate (SGR), feed conversion ratio (FCR), apparent digestibility coefficients, digestive enzymes (pepsin and trypsin) activity and protein metabolism enzymes (alanine aminotransferases) decreased with increasing dietary SPC. The diet with 60% SPC was least cost effective. Results suggest that SPC could replace 60% or less fish meal protein without negatively influencing the growth of juvenile Pelteobagrus vachelli.
Effect of Dietary Lipids on Growth, Feed Utilization, and Protein Sparing in Black Rockfish, Sebastes schlegeli
Authors: Song L. P. , Mao S. Q. , Wang B.L , Xu P , Wang C.S.
Published: February 2021

The effects of dietary lipids on growth and feed utilization of juvenile black rockfish (Sebastes schlegeli) were examined. Triplicate groups of 20 juveniles were fed diets containing 42% crude protein, supplemented with 0%, 3%, 6%, 9% and 12% lipid (% dry matter) for 60 days. At the end of the experiment, survival rate of all groups was at least 88%. Fish fed the diet containing 6% lipids had a significantly (P < 0.05) higher growth rate, better feed conversion and protein efficiency ratios than the other groups. Muscle lipids increased dramatically as the dietary lipid level increased; the highest lipid content was obtained in fish fed the highest lipid diet. Conversely, muscle protein declined as the dietary lipid level increased, and the lowest protein value was in fish fed the 12% lipid diet. Ash and dry matter content did not significantly differ between groups. Increasing the lipid level to 6% was most effective for improving fish growth and feed efficiency.
Effect of Dietary Protein and Lipid Levels on the Reproductive Performance and Body Composition of Angelfish, Pterophyllum scalare (Schultze, 1823)
Authors: Shelar G.S. , Shelar Piyusha , Singh H. , Shirdhankar M.M. , Shingare P.E. , Kulkarni G.N.
Published: February 2021

A study to determine the effect of increasing levels of dietary protein and lipid on Pterophyllum scalare was carried out using twelve semi-purified diets varying in dietary protein (P) and lipid (L) levels (48P8L, 48P12L, 48P16L, 50P8L, 50P12L, 50P16L, 52P8L, 52P12L, 52P16L, 54P8L, 54P12L and 54P16L). Broodstock performance was evaluated based on relative fecundity, fertilization rate, hatching rate, egg size, spawning interval, egg and body composition of P. scalare broodstock. Egg production was highest from fish fed with 50P12L, 52P12L and 52P16L diets. Fish fed the 50P12L and 52P12L diets tended to spawn at shorter intervals. Relative fecundity, fertilization rate, hatching rate, egg size and relative hatchling number, were all significantly higher on diets containing 52% protein than at lower levels. There was no significant difference in hatchling length but hatchling weight differed significantly (P < 0.05) with dietary protein and lipid levels. The protein content of fish and eggs was also influenced (P < 0.05) by dietary protein and lipid levels. It is therefore suggested that in P. scalare broodstock fed with 50-52% protein and 12% lipid, reproductive performance, egg and larval quality improved compared with other diets.
Effects of Dietary Tribulus terrestris Extract Supplementation on Growth, Feed Utilization, Hematological, Immunological, and Biochemical Variables of Nile Tilapia Oreochromis niloticus
Authors: Gültepe Nejdet , Acar Ümit , Kesbiç Osman Sabri , Yılmaz Sevdan , Yıldırım Önder , Türker Ali
Published: February 2021

The present study was conducted for 88 days to evaluate the effect of dietary Tribulus terrestris supplementation on growth performance, feed utilization, and hematological, immunological, and biochemical indices of Nile tilapia, Oreochromis niloticus. A total of 144 Nile tilapia, average body weight 2.61±0.35 g, were divided into four experimental treatments. There were three replicates of each treatment. Four isonitrogenous (40% CP) and isolipidic (10% CL) experimental diets contained T. terrestris extract at levels of 0, 200, 400 and 600 mg/kg respectively. Growth performance and feed utilization of Nile tilapia were significantly higher (p<0.05) in all treatment groups fed with T.terrestris extract supplemented diets than those fed the control diet. There were no significant differences between body composition of fish (p>0.05). Hematocrit, hemoglobin, mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and myeloperoxidase variables were not significantly affected by herb extract (p>0.05). However, mean corpuscular volume (MCV) value and lysozyme activity increased with increasing T. terrestris extract (p<0.05). Serum albumin, total protein, and triglyceride levels were not affected by T. terrestris extract. Serum globulin and glucose levels increased and cholesterol levels decreased in Nile tilapia fed with herbal supplemented diets. The results of the present study suggest that Nile tilapia fed diets containing at least 400 mg/kg T. terrestris extract enhanced growth performance, feed utilization, hematological, immunological, and biochemical indices.
Simultaneous Detection of Streptococcus spp. and Aeromonas spp. from Diseased Tilapia (Oreochromis niloticus) using Multiplex-Polymerase Chain Reaction
Authors: Lukkana M. , Jantrakajorn S. , Piamsomboon P. , Wongtavatchai J.
Published: February 2021

A multiplex Polymerase Chain Reaction (m-PCR) assay was developed for simultaneous detection of two major pathogens, Streptococcal and Aeromonad bacteria, in farmed tilapia. DNA fragments of Streptococcus spp. and Aeromonas spp. were amplified using genus specific primers, C1/C2 and AERF/AERR, which produced PCR of 207 bp and 953 bp, respectively. The lowest concentration of each Streptococcus and Aeromonas spp. extracted genomic DNA from a colony detected by m-PCR was 2 ng. The m-PCR assay was proven applicable for detection of bacterial genomic DNA in tissues (brain and posterior kidney) of infected fish. Specificity of the assay tested with other Gram-positive (Staphylococcus aureus) and Gram-negative water borne bacteria (Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Salmonella enteritidis, Salmonella typhimurium, Vibrio harveyi and Vibrio parahemolyticus) showed no amplification. As Streptococcal and Aeromonad infections are common concurrent bacterial diseases, the m-PCR assay established in this study enabled effective simultaneous detection of these two major bacterial infections responsible for current economic losses in tilapia farming in Thailand.
Hydrolyzed Tuna Meat By-Product Supplement for Juvenile Red Sea Bream, Pagrus major, and its Effect on Growth, Enzyme Activity, Plasma Parameters, and Apparent Nutrient Digestibility
Authors: Mamauag Roger Edward , Ragaza Janice Alano , Koshio Shunsuke , Ishikawa Manabu , Yokoyama Saichiro
Published: February 2021

A growth experiment was conducted on juvenile red sea bream, Pagrus major to investigate the effect of the inclusion in fish diets, of tuna meat by-product hydrolysate which was processed through enzymatic hydrolysis using a commercially available enzyme, derived from Bacillus subtilis. Six experimental diets were formulated in the experiment. Three diets contained 50, 150 and 250 g/kg of TPM-H (tuna meat by-product hydrolysate), and two diets with the unprocessed TPM (tuna meat by-product) at an inclusion level of 50 and 250 g/kg. A control diet was formulated without any addition of the test ingredients. Treatment diets were fed ad libitum to juvenile fish with an initial average body weight of 0.81 ±0.13 g for 56 days. Results of the feeding trial suggest that the inclusion of TPM-H at 250 g/kg in fish diets improved body weight gain rate (3271.58%), feed intake (24.55 g/fish/56 days) and feed conversion efficiency (1.12) of the fish. Apparent nutrient digestibility of hydrolyzed tuna meat by-product improved compared to the unhydrolyzed ingredient. These results suggest that TPM processed as hydrolysates can be efficiently utilized by fish.
Role of antibiotics on chilled storage sperm motility of waigieu seaperch Psammoperca waigiensis (Cuvier and Valencienes, 1828)
Authors: Le Minh Hoang , Nguyen Thuy Thanh Thi , Pham Phuong Linh
Published: February 2021

The objective of the present study was to determine the effect of different antibiotics on chilled storage sperm motility of Waigieu seaperch Psammoperca waigiensis. Collected semen was diluted with an extender at a ratio of 1:3 (semen: artificial seminal plasma ASP) in 1.5ml Eppendorf tubes. Experiments were conducted by adding different antibiotics including: neomycin, gentamycin, or penicillin plus streptomycin at concentrations of 200, 400 and 600 ppm. All treatments were refrigerated at 2oC. The results showed that sperm motility was best with 200 ppm gentamycin. Sperm with gentamycin remained motile up to 36 days.
Pharmacokinetic Profile and Muscle Residue Elimination of Tilmicosin after Oral Administration in Crucian Carp (Carassius auratus)
Authors: Liu Yongtao , AI Xiaohui , Li Le , Yang Hong
Published: February 2021

The aim of this study was to investigate the pharmacokinetics and muscle tissue residue elimination of tilmicosin (TLM) in crucian carp (Carassius auratus) at water temperature of 26±1°C after administration of TLM at three different doses. The crucian carp were randomly divided into two treatment groups and a control group. TLM was administered at two different doses to the treatment groups. Group 1 received a single orally administered dose of TLM at the rate of 50mg/kg body weight, group 2 received three orally administered doses of TLM at the rate of 50 mg/kg body wt. on three consecutive days and Group 3 (the control group) received a normal, drug free diet (0 TLM). TLM concentrations in plasma and muscle tissue were analyzed with ultra highperformance liquid chromatography (UPLC, Waters, USA). Using the 3p97 software, the data of pharmacokinetics was conformed to a two-compartment model. The absorption rate constant (Ka) and absorption half-life (t1/2 kα) of TLM were 1.99 h and 0.349 h, respectively. The distribution half-life (t1/2α) and elimination half-life (t1/2β) of TLM were 2.87 h and 39.89 h, respectively. The maximum concentration (Cmax) of TLM in plasma was 19.36 μg/ml and the time to peak concentration (Tp) was 1.27 h. The area under the plasma concentration-time curve (AUC) was 240.326 µg·h/ml. The distribution volume (Vd/F) of TLM was calculated as 1.968 l/kg. for determination of the muscle residue elimination of TLM used by oral administration at a dosage of 50 mg/kg body weight per day for 3 days of TLM. The results revealed that the elimination of TLM in the crucian carp muscle tissue has a long half-life time of 3.12 d. Based on the above residues, we suggest the withdrawal time should be at least 33 days, calculated by the equation MRL=C0 ek(WDT).
Growth and Feed Utilization by Golden Grey Mullet (Liza aurata) in a Coastal Lagoon Ecosystem, Fed Compound Feeds with Varying Protein Levels
Authors: Karapanagiotidis Ioannis T. , Karalazos Vasileios , Kougioumtzis Nikolaos , Tsiamis Vasileios , Tsiara Vasileios , Neofitou Christos , Karacostas Ioannis , Nengas Ioannis
Published: February 2021

The effects of complimentary compound feeds with varying protein levels on growth performance, feed utilization, and whole body composition were studied in golden grey mullet, Liza aurata. Fish of initial weight 51.1±5.2 g were raised in hapas in a coastal lagoon and fed four iso-energetic diets containing 25%, 30%, 35% or 45% of crude protein for 20 weeks. L. aurata reared on the experimental diets showed relatively low growth rates (SGR ranged from 0.40 to 0.48%/day, and feed utilization parameters (FE ranged from 0.27 to 0.34) among dietary groups consistent with the known slow growth rate of the species. The growth performance and feed utilization of L. aurata was not significantly affected by dietary protein level, despite the fact that there was a trend indicating better fish growth and feed efficiency with increasing dietary protein level. This is indicative of the low protein requirements of L. aurata, although it could be that higher dietary protein concentrations could possibly improve growth performance. The farming of low-trophic species such as L. aurata allows under-utilized trophic resources to be better exploited for fish production. Thus any future advances in understanding the nutrition and feeding of L. aurata under culture conditions, could improve further the potential of this species, especially in regional and coastal aquaculture.
Effects of Dietary Surfactin Supplementation on Growth Performance, Intestinal Digestive Enzymes Activities, and Hepatic Antioxidant Potential of American Eel (Anguilla rostrata) Elvers
Authors: Zhai S-W. , Zhao P-Y. , hi Y , Chen X-H. , Liang Y
Published: February 2021

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.
Effects of Dietary Protein and Lipid Levels on Growth Performance, Feed Utilization and Biochemical Parameters of Barbless Carp (Cyprinus pellegrini)
Authors: Zhang J. , Zhang X. , Wan H. , Chen L. , Lin B. , Li G. , Wang Q.D.
Published: February 2021

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.
The Effects of High Temperatures on Survival Rates and Immunity of Saltwater Clam Meretrix meretrix from Different Geographical Populations
Authors: Chen S.H. , Chen A.H. , Wu Y.P. , Zhang Y. , Cao Y.
Published: February 2021

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.
Dietary Supplementation of Glycyrrhetinic Acid (GA) Promoting Lipid Lipolysis from Blunt Snout Bream Megalobrama amblycephala by TNF-α and LPL Expression
Authors: Liu M-y , Liu G-x. , Zhou M. , Liu W-b. , Jiang G.
Published: February 2021

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.
Bacillus mycoides: An Emerging Pathogen of Ulcerative Disease in Farmed Largemouth Bass Micropterus salmoides
Authors: Cao H. , Yang Y. , Lu L. , Yang X. , Ai X.
Published: February 2021

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
Heat Shock Protein 70 Gene of Ya-Fish (Schizothorax Prenanti) Responses to Thermal Stress and Bacterial Challenges
Authors: Peng S , Liu J.X , Pu Y.D , Wang H. , Geng Y. , Wang K.Y. , Li Z.Q. , Du Z.J. , Chen D.F.
Published: February 2021

The homeostasis of Ya-fish (Schizothorax prenanti) health may be affected by a wide variety of stressful stimuli from the complex aquatic environment. Heat shock proteins are extensively distributed and highly conserved in various animals, particularly Hsp70 which is a novel and potential biomarker for stressful environmental factors and disease conditions. The expression of SpHsp70 was detected to evaluate the potential use of SpHsp70 as a warning signal for some stimuli. In this study, freshwater Schizothorax prenanti were exposed to thermal stress and pathogenic bacteria in the aquatic environment. Results showed that SpHsp70 were ubiquitously and differentially expressed in nine examined organs/tissues. In Ya-fish, stessorspecific reactions were observed after different bacterial challenges. At the acute stage, SpHsp70 expression was significantly up-regulated in the kidney after Streptococcus agalactiae challenge, however SpHsp70 expression significantly increased in the spleen after Aeromonas hydrophila challenge. These reactions suggest that the response of SpHsp70 to bacterial stimuli depends on different stressors. Hence, thermal sensitivity and stressorspecificity precluded the simple use of SpHsp70 as warning information in S. prenanti.