bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Three Diets on Growth and Survival Rates of African Catfish Heterobranchus bidorsalis Larvae
Authors: Alla Yao Laurent , Célestin Ble Melecony , Célestin Atse Boua , Tidiani Kone
Published: February 2021

Investigations are underway in the Centre de Recherches Océanologiques d’Abidjan (Côte d’Ivoire) to find whether the catfish (Heterobranchus bidorsalis) could be an interesting aquaculture species. Within this framework a 28-day aquarium culture feeding trial was conducted to investigate the effects of three diets (Artemia salina nauplii, beef brain enriched with vitamins, and a compound food) on the growth and survival rates in 2-day post hatch H. bidorsalis. The feeding experiments started after the yolk sac of the larvae was absorbed (initial mean weight = 2.03±0.38 mg). Larvae fed Artemia nauplii had a higher growth rate (final mean weight = 708.60±411.61 mg] than those fed beef brain (381.81±118.88 mg) or compound food (102.72±48.09 mg). Conversely, the beef brain diet yielded a better survival rate (70.47±9.48%) than the Artemia nauplii (38.72±7.74%) or the compound diet (5.37±2.24%). Thus, beef brain can be used as a starter food for larval rearing of H. bidorsalis.
Partial Purification and Characterization of the Inhibitory Substance of Bacillus subtilis against Common Bacterial Fish Pathogens
Authors: Nayak S.K. , Mukherjee S.C.
Published: February 2021

The present investigation was carried out to study the active component of Bacillus subtilis, a gastrointestinal bacterium of mrigal (Cirrhinus mrigala) that shows inhibitory activity against a wide range of fish pathogens. The bacterium was found to inhibit all the fish pathogens and an extra cellular protein fraction (ECP) of 5-10 kD was found to be the active component responsible for inhibitory activity. The component was heat stable (60°C for 1 h) and a change in pH had no effect on the antibacterial activity. The protein fraction was sensitive to trypsin, chymotrypsin, lysozyme, and proteinase K at 2.5 mg/ml and resistant at 0.1 and 0.5 mg/ml. The present investigation confirmed that the active component of the B. subtilis responsible for antibacterial activities against common fish pathogens is a low molecular weight protein fraction (5-10 kD). A protein or peptide with such a low molecular weight has the potential to serve as an alternative health management strategy for combating disease in aquaculture.
Effects of L-Carnitine on Growth of Individually Cultured Cladoceran, Moina micrura
Authors: Savas S. , Erdogan O. , Cicek N.L.
Published: February 2021

The cladoceran, Moina micrura, is a potential alternative live food for fish larvae. The effects of L-carnitine enrichment on first reproduction age, population density, and growth rate in M. micrura were determined. The cladocerans were enriched at 10 levels of L-carnitine (0, 0.001, 0.01, 0.1, 1, 10, 100, 500, 1000, and 1500 mg/l) dissolved in 30 ml Chlorella vulgaris culture medium for 17 days. The first reproduction age was stimulated by the supplemental L-carnitine. The population density was highest in the 1 mg/l treatment. The highest population growth rate was obtained in the 10 mg/l treatment, but it did not differ from the growth rate in the 0.1, 1, or 100 mg/l treatments. Consequently, the optimum L-carnitine concentration for M. micrura is 1 mg/l. Results suggest that L-carnitine can be a positive factor in enhancing the use of M. micrura as an alternative live food for fish larvae.
Dietary Zinc and Cobalt Requirements of Fry of Seabass (Lates calcarifer) and Catfish (Clarias batrachus)
Authors: Sapkale P.H. , Singh R.K.
Published: February 2021

An 8-week experiment was conducted to determine the cobalt and zinc requirements of fry of seabass (Lates calcarifer) and catfish (Clarias batrachus). Fifteen diets for each fish were formulated with varying concentrations of cobalt and zinc, alone and in combination. The control diet was not supplemented with cobalt or zinc. The diets for L. calcarifer had 45% protein, while the diets for C. batrachus had 30%. The diet that produced the best growth for L. calcarifer (1100%) contained 2.5 mg Co + 45 mg Zn/kg diet and for C. batrachus (1149%) contained 5 mg Co + 30 mg Zn/kg. Growth in the control L. calcarifer was 738% and in the control C. batrachus was 428%. For both species, the food conversion ratios were best in the above diets, 1.17±0.52 for L. calcarifer and 1.40±0.62 for C. batrachus as opposed to 1.89±0.39 and 2.54±0.61 for the respective controls.
Growth and Feed Efficiency in Mangrove Red Snapper, (Lutjanus argentimaculatus Forsskal 1775) Fed Practical Diets Supplemented with L-ascorbyl-2-monophosphate-Mg
Authors: Catacutan Mae R. , Pagador Gregoria E. , Doyola-Solis Ellen , Teshima Shinichi , Ishikawa Manabu
Published: February 2021

Growth and feed efficiency were determined in red snapper, Lutjanus argentimaculatus (Forsskal 1775), fed diets containing L-ascorbyl-2-monophosphate-Mg (AMP). Fish (13.39±0.08 g) were fed a practical diet without vitamin C supplement for four weeks then stocked in twelve 650-l tanks at 30 fish/tank and fed one of four practical diets containing AMP at 0, 60, 180, or 540 mg/kg dry diet for 17 weeks. Survival rates in all treatments were similar (88.9-98.9%). Fish fed the 0 or 540 ppm diets had inferior final average weights, protein efficiency ratios, and feed conversion ratios than fish fed the 60 or 80 ppm diets (p<0.05). Growth of fish fed the 0 or 540 ppm diets slowed down on day 60 and fish fed the AMP-free diet exhibited clinical signs of vitamin C deficiency with a soft body and a significantly high (p<0.05) hepatosomatic index. Ascorbic acid in brain and liver tissues rose with the level of dietary AMP. Fish fed the 540 ppm diet had significantly lower hematocrit (p<0.05) than fish fed the 60 or 180 ppm diets. Histological analysis of the liver and kidney of fish fed the 180 and 540 ppm diets showed changes indicative of possible toxic effects. Based on growth, feed efficiency, tissue histology, and hematocrit level, AMP at 540 ppm is toxic to snapper. Thus, supplementation of 60 ppm AMP or its equivalent 26 ppm ascorbic acid in practical diets for red snapper promotes optimum growth and feed efficiency and prevents vitamin C deficiency symptoms.
An Improved Method of DNA Extraction from the Shell of the Pacific Oyster, Crassostrea gigas
Authors: Zhang Guofan , Wang Xiaotong , Song Xiaorui , Li Li
Published: February 2021

We earlier developed a method to extract DNA from in vivo-sampled mantle tissue of the bivalve Pacific oyster (Crassostrea gigas) for molecular marker-assisted selection (MAS) in breeding. However, mortality was too high when using this method. In the current study, a more efficient and safer method of extracting DNA from the oyster shell was developed, based on the improved phenol-chloroform DNA extraction method. Both nuclear DNA and mitochondrial DNA were successfully extracted from the oyster shell, and mortality was 0%. These results illustrate the safety of extracting DNA from the bivalve shell. In addition, because DNA is a cellular component, the results provide molecular evidence that cells are likely involved in shell formation.
Sperm Characteristics of Wild European Flounder (Platichthys flesus luscus)
Authors: Sahin Temel , Günes Erdinç , Aydin Ilhan , Kurtoglu Ilker Zeki
Published: February 2021

The spermatologic characteristics of European flounder (Platichthys flesus luscus) were determined. Flounder were collected during the spawning season and sperm of eight males was extracted by abdominal massage. Body weight and total length of the flounder were measured, volume, motility, duration of motility, spermatocrit, density, and pH of the sperm were determined, and correlations between the spermatologic characteristics and weight and length were investigated. Mean values were 0.7±0.16 ml for sperm volume, 87.5±3.66% for motility, 22.0±1.49 min for duration of motility, 94.0±1.22% for spermatocrit, 2.7±0.16 × 109/ml for density, and 6.9±0.05 for pH. Body length and sperm volume had positive correlations with body weight (p<0.01), but the correlation between length and sperm volume was negative (p<0.01). Likewise, the correlations between spermatocrit and total length, sperm volume, and density were negative (p<0.05).
Effects of Total Replacement of Fishmeal with Spirulina Powder and Soybean Meal on Juvenile Rainbow Trout (Oncorhynchus mykiss Walbaum)
Authors: Hernández Luis Héctor Hernández , Flores Gerardo Hernández , Araiza Mario Alfredo Fernández , López Omar Angeles
Published: February 2021

Juvenile rainbow trout (Oncorhynchus mykiss) were fed diets in which fishmeal was totally replaced by mixtures of Spirulina powder and soybean meal. Three experimental diets were formulated with 75% Spirulina and 25% soybean meal, 50% Spirulina and 50% soybean meal, and 25% Spirulina and 75% soybean meal. A commercial diet and a diet with 100% fishmeal served as controls. Diets were fed to triplicate groups of 10 juveniles with an initial weight of 6.8±0.4 g for 50 days. At the end of the experiment, growth performance, oxygen consumption, nitrogen and phosphorus excretion, protein digestibility, and serum protein content and lysozyme activity were evaluated. Data were analyzed by one-way ANOVA. Growth performance was not significantly affected by the experimental diets, but values tended to be lower as the level of dietary soybean meal increased. Among the experimental diets, the 75% Spirulina/25% soybean diet produced the best growth performance. Further, in fish fed this diet, the apparent coefficient of digestibility of protein was higher than 98% (as with all diets), oxygen consumption was lower and lysozyme activity was higher than in fish fed other replacement diets, and dissolved phosphorus and phosphorus in feces were similar or lower than in the controls. The present research shows the possibility of using mixtures of Spirulina powder and soybean meal as total substitutes of fishmeal in diets for juvenile rainbow trout.
Level of L-ascorbyl-2-monophosphate-Mg as a Vitamin C Source in Practical Diets for the Asian sea bass, Lates calcarifer
Authors: Catacutan Mae R. , Pagador Gregoria E. , Doyola-Solis Ellen Flor , Ishikawa Manabu , Teshima Shinichi
Published: February 2021

The stable vitamin C derivative, L-ascorbyl-2-monophosphate-Mg (AMP), was used as a supplement in practical diets for Asian sea bass, Lates calcarifer. Optimum growth, liver ascorbic acid (AA) saturation, and wound healing were determined. Sea bass (78.9±0.4 g) were fed a maintenance diet without vitamin C supplement for 25 days, then distributed into fifteen 1500-l oval fiberglass tanks at 30 fish each and fed one of five practical diets containing 0, 50, 100, 200, or 400 AMP mg/kg diet for 14 weeks. Fish fed the AMP-free diet exhibited clinical signs of vitamin C deficiency and significantly poorer final average weight, specific growth rate, protein efficiency ratio, feed conversion ratio, and hematocrit level (p<0.05). The level of AA in the sea bass brain increased as the level of dietary AMP increased. The AA concentration in the liver was similar at all AMP dietary levels. Body calcium of sea bass fed the AMP-free or 50 mg diets was significantly lower (p<0.05) than in fish fed the other diets. AMP enhanced wound healing regardless of supplement level, but fish fed the highest dietary AMP (400 mg/kg diet) exhibited histopathological changes in the liver. The dietary level of 50 mg AMP/kg diet was adequate for optimum growth, liver AA saturation, and prevention of clinical signs of vitamin C deficiency in 80-220 g sea bass. However, 100 mg AMP per kg diet was necessary for optimum body calcium.
Growth and Survival of Anadara inaequivalvis (Bruguiere, 1789) in Sufa Lagoon, Izmir, Turkey
Authors: Acarli Sefa , Lok Aynur , Yigitkurt Selcuk
Published: February 2021

The growth and survival of 5, 7, 9, and 11-mm juvenile blood cockle (Anadara inaequivalvis) cultured in suspended nets in Sufa Lagoon, Izmir, Turkey, were investigated. Shell length, width, and thickness and total weight were measured monthly during May 2007-May 2008. Temperature was measured every 6 h. Salinity, chlorophyll a, particulate organic matter, particulate inorganic matter, and total particulate matter were followed every two weeks. Mean increases were 16.68 and 13.46 mm and 3.62 and 5.74 g for small and large spat, respectively. Length increased significantly faster in small cockle than in large cockle (p<0.05). Survival was 65% and 100% in small and large cockles, respectively (p<0.05). Von Bertalanffy growth parameters L∞ (27 mm) and k (0.28/month) showed that growth performance (Ф′ = 3.22) was greater than for other species in the natural population. Slope b from the length-weight relationship was 3.098±0.115, indicating significantly better allometric growth (p≤0.05). Results indicate that A. inaequivalvis is a good candidate for suspended aquaculture in the Sufa Lagoon, Turkey.
Effects of Cumin-Supplemented Diets on Growth and Disease (Streptococcus iniae) Resistance of Tilapia (Oreochromis mossambicus)
Authors: Yilmaz Sevdan , Ergün Sebahattin , Turk Necla
Published: February 2021

The effects of dietary cumin (Cuminum cyminum) as a feed additive on growth performance and disease resistance of tilapia (Oreochromis mossambicus) were studied. Five isonitrogenous (37% crude protein) and isocaloric (18.6 kj/g) diets were formulated to contain 0% (control), 0.5%, 1.0%, 1.5%, or 2.0% cumin. Fifteen aquaria (80 l) were stocked with 15 fish (0.56±0.02 g), each, and fish were fed one of the five diets for 75 days. The cumin supplementation did not affect the feed conversion rate (FCR) or specific growth rate (SGR). Cumulative mortality was 60% in fish fed the 0% control diet and challenged with Streptococcus iniae. However, in fish fed the 1.0%, 1.5%, or 2.0% supplemented diets, mortality was only 10.42%, 31.25%, and 37.50%, respectively. In conclusion, a dietary cumin level of 1% provides the best survival rate for tilapia, O. mossambicus, without adversely affecting growth performance or feed utilization.
RAPD-PCR and Outer Membrane Protein Characterization of Vibrio alginolyticus and Vibrio parahaemolyticus Isolated from Diseased shrimp
Authors: Marhual N.P. , Das B.K. , Pradhan J. , Swain P. , Mishra B.K. , Eknath A.E.
Published: February 2021

Vibrio alginolyticus and V. parahaemolyticus were characterized by random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) and profiling of outer membrane proteins (OMP) to the genetic level to enable easier identification of these microorganisms from diseased shrimp (Penaeus monodon) and adopt control measures. Of 20 tested Operon primers (OPC), only OPC5 and OPC18 were used for PCR amlification of 70 isolates representing three strains of each species. OPC5 amplified 1-8 bands with sizes ranging 0.42-2.95 Kb in V. alginolyticus, 5-10 fragments with sizes ranging 0.449-3.55 Kb in V. parahaemolyticus, and one unique common band of 1.34 Kb in both species. When OPC18 was used, one dark band (2.4 Kb) was common to all V. alginolyticus strains and another dark band (1.77 Kb) was common to two strains and the V. alginolyticus ATCC reference strain. One protein band (37.63 kDa) was common to both V. alginolyticus and V. parahaemolyticus and could be used as a diagnostic OMP marker for both species. The simpler and more rapid dot-ELISA and indirect ELISA methods confirmed identification of these pathogenic bacteria.
Effect of Nonsteroidal Aromatase Inhibitor on Sex Reversal of Oreochromis mossambicus (Peters, 1852)
Authors: Das R. , Rather M.A. , Basavaraja N. , Sharma R. , Udit U.K.
Published: February 2021

In the present study, the efficacy of letrozole, a potent nonsteroidal aromatase inhibitor, and 17a-methyltestosterone on gondal sex differentiation and sex reversal was examined in Mozambique tilapia (Oreochromis mossambicus). Among the doses tried in the experiment, 100 mg letrozole, 200 mg letrozole, and 50 mg 17a-methyltestosterone/kg produced male dominated populations (97-100% males). The combination of 100 mg letrozole+25 mg 17a-methyltestoster/kg yielded 100% males while the combination of 50 mg letrozole+25 mg 17a-methyltestosterone/kg yielded 92% males. The control group consisted of 48.05% males and 51.95% females, close to the normal sex ratio of 1:1. Survival ranged 85.61-94.31% in the treated groups, significantly higher than 73.83% in the control (p<0.05). In general, the letrozole and combination treatments resulted in a slight alteration in the gonadosomatic index of the tilapia. Administration of letrozole alone or in combination with 17a-MT did not adversely affect the proximate composition of the muscle. Results suggest that letrozole and 17a-methyltestosterone have the potential to produce 100% male populations in Mozambique tilapia and that inhibition of aromatase activity influences sex differentiation in Mozambique tilapia.
Highly Unsaturated Fatty Acid (HUFA) Retention in the Freshwater Cladoceran, Moina macrocopa, Enriched With Lipid Emulsions
Authors: Loh J.Y. , Ong H.K.A. , Hii Y.S. , Smith T.J. , Lock M.W. , Khoo G.
Published: February 2021

Fatty acid profiles of Moina macrocopa enriched with lipids from inexpensive squid or canola oil were compared with profiles of Moina enriched with a commercial enrichment diet, A1 DHA Selco® (ADS). Arachidonic acid (AA) significantly increased from <0.01 to 0.28 mg/g body weight in Moina enriched with ADS at 1 g/l for 12 h and to 0.38 mg/g in Moina enriched in 2 g/l canola oil for 12 h. The highest increase in eicosapentaenoic acid (EPA; from 0.15 to 0.38 mg/g) was obtained when Moina were enriched in 1 g/l ADS for 12 h. The highest increases in docosahexaenoic acid (DHA; originally <0.01) were obtained in Moina enriched in 1 g/l ADS for 12 h (increased to 0.09) or in 2 g/l ADS for 24 h (rose to 0.8 mg/g). The AA:EPA ratio was highest in Moina treated with 2 g/l canola oil for 12 h or 2 g/l squid oil for 24 h. The AA:DHA ratio was highest in Moina enriched with 2 g/l canola oil for 12 h while the DHA:EPA ratio was highest in Moina enriched with 2 g/l squid oil for 24 h.
Effect of Supplemented Bacteria (Lactobacillus sporogenes) on Growth of Macrobrachium rosenbergii Postlarvae
Authors: Prasad Laxmi , Nayak B.B. , Kohli M.P.S. , Reddy A.K. , Srivastava P.P.
Published: February 2021

A feeding trial was conducted for 75 days to study the effects of dietary Lactobacillus sporogenes on growth and body composition in postlarvae of the giant freshwater prawn, Macrobrachium rosenbergii (de Man). Postlarvae were fed one of five experimental feeds containing 0.0% (control diet), 0.1%, 0.2%, 0.5%, or 1.0% L. sporogenes. Weight gain, specific growth rate, and protein efficiency ratio tended to increase as the postlarvae were fed the probiotic-supplemented feeds in increasing levels up to 0.5%. The best growth performance was obtained in postlarvae fed 0.5% L. sporogenes containing 1.67 x 105 colony forming units/100 g feed. When fed 1.0% L. sporogenes, growth performance dropped. Tissue protein content was highest in animals fed the 0.5% feed while lipid content was significantly highest in postlarvae fed the control.
Induced Reproduction of Aphanius fasciatus by Ecophysiological Conditioning and Hormonal Treatment in Fresh and Marine Water
Authors: Mordenti Oliviero , Di Biase Andrea , Zaccaroni Annalisa , Bastone Giuseppe , Scaravelli Dino
Published: February 2021

The Mediterranean toothcarp (Aphanius fasciatus) can be used to biologically control mosquito larvae. The reproductive performance of 234 Mediterranean toothcarp (180 females and 54 males) was investigated. Reproductive factors were determined in fish kept in fresh or saline water (males and females together), and in fish kept separately by sex in saline water and hormonally-treated with carp pituitary extract (CPE). In the hormonally-treated group, the combined effect of temperature, photoperiod, and hormonal treatment induced the best ovary maturation and larvae production rates. The rate of reproduction was very high (average eggs/female: 5.9-10.5) compared to natural reproduction in the wild (average eggs/female: 2-4). Additionally, the hatching rate was 97-100%. The results of this study show that reproduction of Mediterranean toothcarp can be controlled in an artificial environment: the lack of mortality in adults during acclimation and conditioning in fresh and marine waters indicates good domestication and plasticity in reproductive parameters.
An Arithmetic Index Based on Shell Height, Length, and Width, for Potential Selection of Soft-Body Wet Weight in Pacific Oyster, Crassostrea gigas
Authors: Wang Xiaotong , Liu Ting , Liu Yongshan , Feng Peiyong
Published: February 2021

The Pacific oyster, one of the most widely grown bivalves, has a long commercial history, a large consumer base, and is one of the most important commercially cultured mollusks in the world. Only the soft body is edible therefore increasing the soft-body wet weight (SBWW) is the main breeding objective for oysters. The SBWW cannot be measured in-vivo. In general, the shell height (H) or shell length (L) are used to indirectly choose SBWW. But they are diverse and susceptible to environmental influences so they are not indicative of higher SBWW and inappropriate for the selection of optimal brooders. In this study, H, L as well as shell width (W) of wild and cultured populations were measured and the correlation coefficients between H, L, W, HLW (the arithmetic index based on shell height, length and width) and SBWW were calculated and found to be potential indicators for selective breeding of SBWW in Pacific oyster.
Protein/energy ratio and HUFA content in the diet of Pangasianodon hypophthalmus (Sauvage, 1878) fingerlings: Effect on growth and flesh quality
Authors: Kumar Sikendra , Munilkumar S. , Gupta S. K. , Jain K. K. , Pal A. K. , G.M Siddaiah , Prakasha Chandra
Published: February 2021

A 60 day feeding trial was conducted to study the effect of varying levels of protein/energy (P/E) ratio and highly unsaturated fatty acid (HUFA) supplemented diet on growth and flesh quality parameters of Pangasianodon hypophthalmus fingerlings. One hundred and eighty fingerlings of uniform weight (4.32±0.08g) were randomly distributed into five treatment groups with three replications. The five different treatment groups were: Control - T0H0 (basal feed+117 mg/kcal, P/E ratio); T1H0 (basal feed +100 mg/kcal, P/E ratio); T2H0 (basal feed +133 mg/kcal, P/E ratio); T3H1 (basal feed +100 mg/kcal, P/E ratio+1% HUFA) and T4H1 (basal feed + 133 mg/kcal, P/E ratio+1% HUFA). Significantly higher (P<0.05) weight gain (WG) %, specific growth rate (SGR), and feed conversion efficiency (FCE) were observed in the T4H1 and T2H0 groups. Feed conversion ratio (FCR) and protein efficiency ratio (PER) were lowest in the T4H1 group. T3H1 and T4H1 groups manifested significantly higher (P<0.05) value for flesh quality indices such as springiness, adhesiveness, gumminess, and chewiness. Lowest hardness value was found in T4H1 group. Significantly higher (P<0.05) EPA and DHA deposition in fish muscle was observed in T4H1 group. Protease activity was higher in T4H1 group followed by T2H0 group and lowest in T1H0 group. Amylase activity was lower in T2H0 and T4H1 groups. Overall results revealed that P/E ratio of 133 mg/kcal with additional supplementation of 1% HUFA in the diet enhances growth and improves flesh quality of P. hypophthalmus fingerlings
Characterization of Nitrifying Bacterial Community in a Mariculture Wastewater Treatment Using SBR System
Authors: Che J , Wang L. L , Wang X. T. , Yang G. J , Yang Y , Xu W. P , Xu Y. P.
Published: February 2021

Sequencing batch reactors (SBR) have been used in the biological treatment of aquaculture wastewater. In this study, we investigated the microbial community of a SBR that used diatomite earth (20 g/L) as the sludge carrier material. Marine wastewater in which ammonia content was 42.08 to 55.88 mg/L was supplied to the SBR every 12 h over a treatment period of 65 days. During the first 20 days, the concentration of NH4-N decreased gradually, while nitrite (NO2-N) became the major nitrogen compound, reminiscent of the development of an ammonia-oxidizing process. Over the next 20 days, the concentration of NH4-N decreased further due to conversion to NO3-N. More than 99% of the NH4-N was converted to NO3-N over a period of 40-65 days. Denaturing gradient gel electrophoresis (DGGE) assay showed that bacteria of the genus Flavobacterium were present during the entire treatment period, while α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, and Sphingobacteriia started to accumulate after the first 20 days. Fluorescence in situ hybridization (FISH) assay identified Nitrobacter and Nitrosomonas as the main bacteria involved in the conversion of NH4-N to NO3-N. Diatomite earth therefore acted as an efficient sludge carrier by shortening the settling time and facilitating bacterial colonization. This SBR was capable of rapid removal of NH4-N. This warrants further investigation at the pilot-scale in an actual mariculture farm
Penaeus vannamei, white feces syndrome, Vibrio cholerae, pathogenicity, antibiotic susceptibility
Authors: Cao Haipeng , Wen Lefu , He Shan , Lu Liqun , Yang Xianle , Chen Baiyao
Published: February 2021

Whiteleg shrimp Penaeus vannamei is an important commercial shrimp species cultivated in China and many other countries worldwide. Bacteriosis is a major economic problem that inhibits the farming of this species in fresh water. White feces syndrome is an emerging epidemic in freshwater cultured P. vannamei and has caused significant economic damage. Only scarce information is available on Vibrio cholerae as a possible causal agent for this disease. In this study, a virulent strain BB31 was isolated from diseased P. vannamei suffering from white feces syndrome, and identified as a V. cholerae isolate through phylogenetic analysis and phenotypic characteristics. A phylogenetic tree was constructed to examine the relationship of isolate BB31 to other V. cholerae isolates. Three genes encoding hemolysin, outer membrane protein, and cholera toxin transcriptional activator were present in the BB31 isolate confirming its potential pathogenicity. In addition, isolate BB31 is known to have developed resistance to penicillin, sulfonamides and cephalosporin antibiotics. This was demonstrated when screened against a range of common antibiotics for aquaculture and veterinary use. To the best of our knowledge, this is the first report of white feces syndrome caused by V. cholerae in freshwater farmed P. vannamei.
Recovery of Pseudomonas aeruginosa from Diseased Grass Carp (Ctenopharyngodon idella) in China
Authors: Luo Zhang , Bai Xiaohui , Xu Yunxia , Zhang Zhengguo , Hao Shuang , Li Nan , Feng Shouming
Published: February 2021

An epizootic was discovered in grass carp (Ctenopharyngodon idellus) in earthen ponds in Ninghe, Tianjin Province, northern China, from May to June 2013. The cumulative mortality was 30% within 25 days, and the diseased fish presented with hemorrhaging in the abdominal wall, ascites in the abdomen and pale liver. Strains named PA131207 and PA131208 were isolated from the moribund fish, and were identified as Pseudomonas aeruginosa according to both biochemical tests and phylogenetic analysis derived from the 16S rRNA gene. The pathogenicity of PA131207 was confirmed by infectivity experiments and histopathological examination. Antimicrobial susceptibility tests showed that PA131207 was resistant to 9 of 15 antimicrobial agents tested.
Effects of Dietary Supplementation with Fermented Ginkgo Leaves on Innate Immunity, Antioxidant Capability, Lipid Metabolism, and Disease Resistance Against Aeromonas hydrophila Infection in Blunt Snout Bream (Megalobrama amblycephala)
Authors: Cao Fuliang , Lu Yan , Zhang Xuhui , Zhao Linguo , Yang Juxian , Qin Xiaoshu , Liu Wenbin , Yu Wanwen
Published: February 2021

This study was conducted to investigate the effect of Candida utilis and Aspergillus niger, combined with fermented Ginkgo biloba leaves (FGB) on immunity, antioxidant capability, lipid metabolism, and disease resistance against Aeromonas hydrophila infection in juvenile blunt snout bream (Megalobrama amblycephala). Fish were fed basal diets supplemented with fermented Ginkgo biloba leaves FGB1(0.125%), FGB2(0.25%), FGB3(0.5%), FGB4(1.0%), or Control (0.00%) respectively. At the end of the 60-day feeding trial, fish were challenged by A. hydrophila and mortality rate was recorded for the next 7 days. Results showed that, compared with the control, serum myeloperoxidase (MPO) activity of groups FGB1 and FGB2, alkaline phosphatase (AKP) and lysozyme (LZM) activity of group FGB2 increased significantly (P<0.05), while malondialdehyde (MDA) and low density lipoprotein cholesterol (LDL-C) contents of group FGB2, immunoglobulin M (IgM) activity of group FGB4 decreased significantly (P<0.05). Furthermore, Acid phosphatase (ACP), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH) and triglyceride (TG) activities were not affected (P>0.05). After A. hydrophila challenge, the relative mortality of group FGB1 and FGB2 were significantly lower than the control (P<0.05), however the highest rate was in group FGB4. Results of this study indicate that dietary supplementation of 0.125%~0.25% fermented G. biloba leaves can significantly enhance immunity, antioxidant capability, and lipid metabolism of blunt snout bream, as well as improve its disease resistance.
Oxygen Consumption and Lethal Dissolved Oxygen Level of Hybrids of Siniperca chuatsi♀ × S. scherzeri♂
Authors: Sun Jijia , He ianguo , Li Guifeng , Liu Li , Hou Xiaocui $Wang
Published: February 2021

Oxygen consumption rate (OCR) and lethal dissolved oxygen levels (DO) of the hybrids (225.3 ± 4.6 g) of Siniperca chuatsi ♀ × S. scherzeri ♂, were determined after acclimating the fish to 15, 20, 26 and 30°C for 20 days. The same parameters were measured for hybrids with different body weight (146.8 ± 6.3 g, 234.3 ± 8.4 g, 273.9 ± 3.3 g, 327 ± 5.1 g) at 26 °C. OCR increased significantly (P <0.05) with increasing acclimation temperature between 20-26°C, and decreased with increasing body weight. Final preferred temperature estimated from the Q10 was between 26-30°C. The lethal DO concentration for the hybrids at 30°C was significantly higher (P <0.05) than at other temperatures. OCR over the daily cycle under natural lighting conditions was also determined at 26°C. It showed a circadian rhythm with the lowest point at 0830 and peak rates at 1430. Results show that the hybrid has a higher stress tolerance and higher stocking density than the female parent S. chuatsi and indicate their culture potential in subtropical freshwater regions.
Growth Performance, Nutrient Utilization, Metabolic and Digestive Enzymes Studies in Mrigal (Cirrhinus mrigala) Juveniles Fed Graded Levels of Carbohydrate
Authors: Aderolu A.Z , Sahu N.P
Published: February 2021

A 45-day experiment was carried out to evaluate the growth performance, digestive enzyme activity, and gene expression in mrigal fish Cirrhinus mrigala, fed graded levels of carbohydrate. Three isonitrogenous and isolipidic diets containing either 30, 40 or 50% carbohydrate were formulated using purified ingredients. One hundred and eight Cirrhinus mrigala fingerlings (av. wt. 5.83-6.08g) were equally divided into three groups in 9 plastic tanks of 150L capacity each. Each of the three experimental diets was fed to triplicate groups of fish held under natural light cycle of 12h daylight and 12h darkness. % Weight Gain (WGR), specific growth rate (SGR), feed conversion ratio (FCR) and hepato-somatic index (HSI) were evaluated and found to vary significantly (P<0.05) in relation to the level of carbohydrate in the experimental diets. No significant difference (P>0.05) was found in % weight gain, SGR, and FCR, between the 30% and 50% carbohydrate fed groups but HSI increased significantly across the inclusion levels. Amylase enzyme activity was highest in 40% fed group relative to the 30% and 50% groups. Chymotrypsin and trypsin activities were not significantly different between the 40% and 50% carbohydrate fed groups. Various metabolic enzyme activities in the muscle [aspartate aminotransferase (AST), alkaline amino transaminase (ALT) and malate dehydrogenase (DH)] varied significantly (P<0.05) in response to increased levels of carbohydrate. Gene expression among the digestive enzymes reflected both transitional and translation effect; amylase and trypsin exhibited higher expression with the increasing level of carbohydrate of the experimental diets but results were reversed for chymotrypsin expression. In our study, gene expression was initially significantly higher but then decreased. No consistent pattern was found among the different digestive enzymes.
Effect of Live, Frozen and Artificial Feeds on Digestive Enzymes, Aminotransferase, Histology of Liver and Intestine in Mandarin Fish Hybrid (Siniperca chuatsi ♀× Siniperca scherzeri♂)
Authors: Li Yan , Shi Jianhua , Shi Shunchang , Liu Zhijun , Li Zhu , Li Jianzhong
Published: February 2021

To partially or entirely replace the use of live foods for mandarin fish (Siniperca chuatsi ♀× Siniperca scherzeri♂) with frozen or artificial feeds, a detailed understanding of their digestive physiology and the influence of these replacements is needed. The experiment was conducted in a recirculation system for 10 weeks. At termination of the feeding trial, protease activity in the alimentary tract and aspartate aminotransferase (AST) in the livers of fish fed frozen feed were significantly higher than those fed artificial feeds. Fish fed artificial feed had the highest AST and alanine aminotransferase (ALT) serum activity in serum which suggests that the liver was damaged to some extent. These results were further confirmed by histology of the liver. Fish fed the artificial feed had serious hepatocyte vacuolization and disorganization. The mucosal epithelium of intestine in fish fed frozen and artificial feed had poorly developed enterocytes with a shortening of the microvilli, decreased absorptive vacuoles and hyperplasia of the lamina propia. n In addition to tissue damage there was a reduction in the ability of fish to digest frozen and artificial feed. The results of this study indicate that the mandarin fish hybrid readily feeds on frozen and artificial feeds. However, a more appropriate artificial feed for this species is needed to improve the digestive function and histology of the digestive tract.
Isolation and Identification of Tenacibaculum maritimum, the Causative Agent of Tenacibaculosis in Farmed Sea Bass (Dicentrarchus labrax) on the Aegean Sea Coast of Turkey
Authors: Yardımcı R. Eda , Timur Gülşen
Published: February 2021

In this paper we describe the isolation and identification of Tenacibaculum maritimum from infected sea bass by using bacteriological, histopathological, and molecular methods. Fish were reared in five different floating net cage farms and two hatcheries located in several regions on the Aegean Sea coast of Turkey. We observed external erythemic and erosive jaw and operculum superficial or deep ulcerative skin lesions on the head and body surfaces, gill rot, hemorrhagic and erythemic fins in infected individuals, and slight exophthalmia was also detected. In addition, internal hemorrhages and hyperemia in the visceral organs and bloody fluid in the peritoneal cavity were observed. Bacteria isolated from the kidney and skin lesions of the infected fish produced flat, pale colored colonies on Flexibacter maritimus medium (FMM), marine enriched Cytophaga agar (MECA) and Marine Agar (MA) and were identified as Tenacibaculum maritimum, Vibrio sp. and motile or non-motile Aeromonas species. Histopathologically, degeneration and liquefactive necrosis in liver, kidney, and spleen was observed in the individuals infected with Tenacibaculum maritimum. The identification of T. maritimum was performed directly from the infected fish tissue using nested polymerase chain reaction. In this study, T. maritimum induced mostly mixed infection with Vibrio sp. and motile or non-motile aeromonad species in the four fish farms resulting in 25% mortality. However, this bacterium produced an unmixed infection with the same mortality in young sea bass from only one farm.
Dietary effect of Quillaja saponaria and/or Yucca schidigera extract on growth and survival of common carp Cyprinus carpio, their antioxidant capacity and metabolic response to hypoxic condition
Authors: Angeles Isagani P. Jr. , Chien Yew-Hu
Published: February 2021

This study evaluated dietary effects of extracts of Quillay Quillaja saponaria, and/or Yucca Yucca schidigera on growth and survival of juvenile common carp Cyprinus carpio, and their antioxidant capacity and metabolic response to low dissolved oxygen (DO) stress. For 8 weeks, fish were fed one of 4 different diets. The diets were supplemented with either 150 mg/kg Quillay (QS), 150 mg/kg Yucca (YS), the combination of 75 mg/kg Quillay and 75 mg/kg Yucca (M), or control diet (C) without addition of Quillay or Yucca. Growth and survival were monitored periodically. After rearing, fish were subjected to low DO stress, and after a week, antioxidant capacity (superoxide dismutase, glutathione peroxidase and glutathione reductase) and metabolic response (glucose, triglycerides and lactate) were analyzed. QSfed fish had the highest weight gain among all the treatments. Treatments did not affect fish survival a week after low DO stress. Among antioxidant capacity and metabolic response, significant effects were found only on superoxide dismutase and glucose. QS fed fish had 39% lower plasma superoxide dismutase than the C and M groups. QS and M groups exhibited 29% and 26% lower plasma glucose than the C group, respectively. Overall, the QS diet improved growth and exhibited favorable antioxidant capacity and metabolic response of carp to low dissolved oxygen environment.
Systemic Mycobacteriosis Caused by Mycobacterium marinum in Farmed Meagre (Argyrosomus regius), in Turkey
Authors: Timur G. , Ürkü Ç , Çanak Ö , G. Genç Erköse , Erturan Z.
Published: February 2021

This paper describes systemic mycobacteriosis caused by Mycobacterium marinum, in farmed meager (Argyrosomus regius), in Turkey. Infected two year old fish showed signs of stunted growth, emaciation, slight ascites and exophtalmia, pale gills and significant mortalities. Only one fish sample showed hemorrhagic ulcerative skin lesions at the base of the caudal fin. Internal multifocal white colored granulomas in the spleen, kidney, and liver were observed. Ziehl-Neelsen (ZN) and Gram stained fresh squash mounts of the granulomas revealed Gram and ZN positive rods. Inoculation of sterile homogenates of the visceral organ granulomas on Lowenstein-Jensen slants produced slow-growing (3-4 weeks), yellow to orange colored, photochromogenic acid fast colonies. ZN positive bacterial isolates were identified using commercially available line probe assays (Genotype Mycobacterium CM/AS assay) and hsp65 gene sequencing analyses. According to molecular analysis results, the isolates were identified as Mycobacterium marinum. Epithelioid cell granulomas were microscopically observed in the visceral organs and gills. ZN stained tissue sections exhibited heavy acid-fast rods within the granulomas.
Isolation, Identification, and Pathogenicity of a Virulent Aeromonas jandaei Associated with Mortality of Farmed Pangasianodon hypophthalmus, in India
Authors: Kumar Kundan , Prasad K. Pani , Tripathi Gayatri , Raman R.P. , Kumar Saurav , Tembhurne Meena , Purushothaman C.S.
Published: February 2021

The present study was conducted to investigate the bacterial pathogens involved in the mortality of cultured Pangasianodon hypophthalmus. Diseased fish samples were collected from Maharashtra, India for the isolation of pathogenic bacteria. The pathogenic bacterial isolates were identified using 16S rRNA gene sequencing analysis which revealed that they were 99% identical with Aeromonas jandaei. The bacterial isolates were further characterized using biochemical methods. The lowest bacterial dose which caused 50% cumulative mortality (LD50) in Pangasianodon hypophthalmus was 8.84 X 105 CFU per fish. This was achieved by injecting the fish intraperitoneally with pure culture of A.jandaei isolated from diseased fish. Histopathogical studies revealed necrosis hemorrhaging, and other cellular alterations of different tissues of collected organs viz. gill, liver, and kidney of P. hypophthalmus, observed with the diseased conditions.
Effects of Dietary Emodin Supplementation on Growth Performance, Non-Specific Immune Responses, and Disease Resistance to Aeromonas hydrophila in Juvenile Wuchang Bream (Megalobrama amblycephala)
Authors: Zhang Yuan-yuan , Liu Bo , Ge Xian-ping , Liu Wen-bin , Xie Jun , Ren Ming-chun , Zhou Qun-lan , Sun Sheng-ming , Cui Yan-ting , Chen Ru-li , Pan Liang-kun
Published: February 2021

An 8-week feeding trial was conducted to investigate the effects of dietary emodin supplementation on growth, non-specific immunity, and protection against Aeromonas hydrophila infection in juvenile Megalobrama amblycephala. A basal diet was supplemented with 0 (control), 15, 30, 60 and 120 mg emodin/kg to formulate five experimental diets. Each diet was randomly allocated to triplicate tanks of ﬁsh in a circulating water system (initial average weight 3.49±0.045g, 25 fish per tank). At the end of the feeding trial, fish fed the diet supplemented with 0 and 120 mg emodin/kg had lower weight gain (WG) and speciﬁc growth rate (SGR) than those in the other treatment groups, but no significant differences were observed among diets supplemented with emodin from 15 to 60 mg/kg. A significant increase on feed conversion ratio (FCR) of fish fed diet supplemented with 120 mg emodin/kg was observed. The white blood cell count (WBC), respiratory burst activity, superoxide dismutase (SOD) activity, myeloperoxidase (MPO) activity, malondialdehyde (MDA) content, and tumor necrosis factor-α (TNF-α) activity first increased and then decreased with increase of the dietary emodin levels. Fish fed the 30 mg emodin/kg supplemented diet had higher WBC, respiratory burst activity, SOD and TNF-α activity, and lower MDA content, than fish fed diets supplemented with 0 and 120 mg emodin/kg. In the bacteria challenge experiment with A. hydrophila, fish fed a diet supplemented with 30 and 60 mg/kg had a lower cumulative mortality rate than the control group. These results indicated that appropriate dietary emodin supplementation (especially 30 mg emodin/kg diet) could enhance the growth and immune responses of ﬁsh and improve resistance to infection by A. hydrophila.
Growth and Hemato-Immunological Response to Dietary i-Carrageenan in Labeo rohita (Hamilton, 1822) Juveniles
Authors: Kumar Vikash , Kumar Saurav , Pandey P.K. , Raman R.P. , Prasad K. Pani , Roy Suvra , Kumar Abhay , Kumar Kundan
Published: February 2021

The study was performed over a period of 60 days to evaluate the effect of dietary carrageenan on growth, hematology, biochemistry, and innate immunity in rohu Labeo rohita. A basal diet supplemented with iota (i)Carrageenan at 5, 10 and 20g/kg was fed to three different groups of fish for 60 days. The fish were examined 15, 30, 45, and 60 days after commencement of the study. Parameters for growth (absolute growth, specific growth rate, and percentage weight gain), hematology (total erythrocyte count, total leucocyte count, thrombocyte count and hemoglobin value), biochemistry (total serum protein, albumin, globulin and albuminglobulin ratio), and innate immunity (nitroblue tetrazolium NBT, and myeloperoxidase MPO, activity) were monitored to assess the effect of the iCarrageenan based diet in L. rohita. All the parameters examined (growth, hematology, biochemistry, and innate immunity) increased significantly (P<0.05) in carrageenan-fed groups compared to the control group. However, the highest values for those parameters were found on the 60th day in the group which was fed a 10 g/kg i-Carrageenan diet. The study suggests that a 10 g/kg diet of i-carrageenan enhances immunity and the overall health status in L. rohita.
The Dietary L-Methionine Requirement of the Juvenile Yellow Catfish Pelteobagrus fulvidraco
Authors: Chen Yan , Cao Jun-Ming , Huang Yan-Hua , Zhao Hong-Xia , Chen Bing , Zhu Xuan , Lan Han-Bing , Pan Qing
Published: February 2021

An 8 week feeding trial was conducted to investigate the effects of dietary methionine levels on growth, feed utilization, body composition, and morphometric parameters of juvenile yellow catfish (Pelteobagrus fulvidraco), and to determine their dietary methionine requirement. Six isonitrogenous and isoenergetic diets (405.0 g/kg crude protein and 18.0 kJ/g gross energy) were formulated, and crystalline L-methionine was added to obtain dietary methionine levels of 5.5, 6.7, 7.5, 8.7, 9.5 and 11.3 g/kg dry diet. Fish with an initial weight of 1.4 g were randomly distributed into six groups and fed the respective formulated diets. Increasing amounts of dietary methionine up to 8.7 g/kg dry diet resulted in increased final body weight, rate of weight gain, specific growth rate, feed conversion efficiency and protein efficiency ratio however, a further increase in methionine level resulted in a decrease in these parameters. No significant difference in survival percentages was detected among the dietary treatments. A one-slope quadratic broken-line analysis model, based on specific growth rate and dietary methionine levels, indicated that the dietary L-methionine requirement of juvenile P. fulvidraco is 10.5 g/kg dry diet (accounting for 26.0 g/kg of dietary protein).
The Effect of Streptomycin on Freezing Rainbow Trout (Oncorhynchus mykiss) Sperm
Authors: Ekici Aygül , Baran Alper , Özdaş Ö. Banu , Sandal A. İzem , Yamaner Güneş , Güven Erdoğan , Baltacı Muhammed Ali
Published: February 2021

Mature male and female rainbow trout (Oncorhynchus mykiss) were used to study the effect of different concentrations of streptomycin in a cryopreservation solution on the sperm motility, motility duration, and fertilization rate of rainbow trout. 300mM glucose and 10% DMSO containing diluent was used as a cryopreservation solution. Three different concentrations (3600, 7200 and 10800 μg/ml) of streptomycin were added to the diluent. Our study showed that various concentrations of streptomycin in cryopreservation solution caused a significant reduction in the percentage and duration of rainbow trout spermatozoa motility after freezing-thawing. The percentage of egg fertilization also decreased. When streptomycin-containing groups were compared with each other, a statistical difference was found (p<0.05). However, no statistical difference was observed in terms of the percentage of eyed-embryos.
Characterization of GnRH, ILGFRI and AR Genes in Sturgeon’s Genomics
Authors: Albayrak Gülruh , Şengör Gülgün F. Ünal , Yörük Emre
Published: February 2021

Abstract- In this study, gonadotropin-releasing hormone (GnRH), insulin-like growth factor receptor I (ILGFRI), and androgen receptor (AR) genes coding, were examined by polymerase chain reaction (PCR) analysis and DNA sequencing in three Eurasian sturgeon species: Huso huso, Acipenser stellatus and A. gueldenstaedtii. Amplicons of 190 bp for GnRH, 180 bp for ILGFRI, and 200 bp for AR genes were amplified with specific primer pairs in all species genome. All amplification products were sequenced and compared to reference H. huso genome retrieved from NCBI database by BLASTN analysis. The ILGFRI gene had the most similar sequences (75.96-96.15%) in all species. Gene sequence similarity calculated for AR gene ranged from 48.5- 95.71%. The GnRH gene had more distant sequences (23.48-83.91%) between species. There was moderate similarity between H. huso and the reference H. huso samples. An unauthorized (a sample seized from poachers) sample was more closely related to A. stellatus. Partial coding region of AR gene was registered in NCBI database under Accession Number: KC172108. Five nucleotide changes were detected in this sequence, two of which resulted in changes in amino acid sequence. Also, a partial sequence consisted of two microsatellite regions of two and four nucleotide repeats. Three constructed dendrograms displayed the relationship among species according to certain genomic regions. These findings indicate a high level of diversity among and even within the same species. They also show that these three genes could be useful in species’ identification and characterization