bluuebunny/crossref_metadata_2025 huggingface dataset:
Anesthetic effects of clove oil during handling and transportation of the freshwater prawn, Macrobrachium rosenbergii (de man)
Authors: Vartak Vivek , Singh Ravendra Kumar
Published: February 2021

The present work was conducted to determine the effects of clove oil as an anesthetic on post- larvae (mean length 13.42±0.84 mm) and juveniles (43.57±0.94 mm) of the giant freshwater prawn, Macrobrachium rosenbergii. In the first of three experiments, exposure to ethanol for 15 min was ineffective in tranquilizing the freshwater prawns at concentrations of 75-625 mg/l for postlarvae and 375-5,000 mg/l for juveniles, indicating that ethanol could be used as a solvent for clove oil without contributing to any anesthetic reaction. In the second experiment, prawns were exposed to one of six clove oil concentrations for 15 min (15-125 mg/l for postlarvae; 75- 1,000 mg/l for juveniles). For postlarvae, the fastest induction (0.90±0.05 min) was achieved at the highest concentration (125 mg/l) but all prawns in this treatment died. Induction and recov- ery times in concentrations of 30, 45, and 60 mg/l were all under 15 min. At 75 mg/l, postlarvae were tranquilized in a relatively short period (3.30±0.10 min) and recovery time was maximum (45.17±0.20 min). For juvenile prawns, concentrations of 750 mg/l and up were fatal while 125 and 250 mg/l induced anesthesia in 78.30±0.20 and 66.83±0.18 min, respectively, with recovery in 4.21±0.12 and 16.91±0.16 min. As far as induction and recovery times are concerned, clove oil was a suitable anesthetic only for postlarvae. The third experiment revealed that a concen- tration of 15 mg/l could safely be used to transport postlarvae up to three hours.
Improvement of growth performance in tilapia (Orepochrimis aureus Linnaeus) by supplementation of red clover Trifolium pratense in diets
Authors: Turan Funda
Published: February 2021

This study was conducted to investigate the effects of red clover on growth, body composition, and survival of tilapia, Oreochromis aureus. Three concentrations of dietary red clover (50, 100, 200 mg/kg) were tested for 90 days. The growth rate was significantly better in fish fed 100 mg red clover/kg feed than in the control that contained no red clover (p<0.01). The specific growth rate ranged from 3.79±0.10 in the 200 mg/kg red clover treatment to 4.41±0.05 in the 100 mg/kg treatment. The food conversion ratio, protein efficiency ratio, and apparent net protein utilization were significantly highest in groups fed the 100 mg red clover/kg diet (p<0.01). Survival in groups fed red clover did not differ from that of the control. The highest protein content (19.74%) was obtained in the 100 mg/kg group and it was significantly higher than in all other groups (p<0.05). Moisture and ash contents did not differ among treatments. Lipid content was not significantly affected by red clover dosage. The findings of the present study suggest that 100 mg red clover/kg feed improves the growth rate and feed utilization of tilapia.
Growth and body composition of European catfish (Silurus glanis L.) fed diets containing different percentages of protein
Authors: Bekcan Süleyman , Dogankaya Levent , Cakirogullari Gul Celik
Published: February 2021

European catfish (Silurus glanis) were fed anchovy-based diets containing 30, 35, 40, or 44% crude protein to satiation for 112 days. Data were collected to determine the relationship between dietary protein level and mean weight gain, specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER), daily growth index (DGI), average daily growth (ADG), feed efficiency (FE), and survival. The highest mean weight gain and SGR were obtained with the 40% (59.94 g and 0.74, respectively) and 44% (56.15 g and 0.71) diets. The best FCR (0.97), PER (2.62), DGI (2.18), ADG (1.14), and FE (1.04) were obtained with the 40% protein diet (2.75 kcal/g, digestible energy). Survival was 100% in all treatments. Results indicate that the optimum level of dietary protein for European catfish is 40%.
Consumer willingness to pay for organic sea bass in Turkey
Authors: Budak Fuat , Budak Dilek Bostan , Kacira Ozlem O. , Yavus M. Cihan
Published: February 2021

This study analyzes the willingness of Turkish consumers to pay for organically farmed sea bass (Dicentrarchus labrax). A contingent valuation survey was conducted during 2004 in six super- markets in Adana, Turkey. An ordered probit analysis with a sample selection model was used to determine the probability of consumers’ willingness to pay for organically farmed sea bass by considering related explanatory variables. Results indicate that 91.5% of the respondents would be willing to pay a premium for organically farmed sea bass. Econometric results suggest that willingness to pay is mainly related to household income, education, food safety concerns, whether the respondent is the primary food shopper in household, and whether there are chil- dren under the age of 10 in the household.
cDNA cloning and mRNA expression of growth hormone in Belontiidae (Anabantoidei suborder)
Authors: Degani G. , Jackson K. , Yom-Din S. , Goldberg D.
Published: February 2021

Complete cDNA encoding for the growth hormone (GH) of the Belontiidae fish family (Anabantoidei suborder) was cloned by RACE PCR using several sets of degenerate oligonu- cleotides. GH cDNA of the pearl gourami (Trichogaster leeri; pgGH), cloned from the pituitary, included the 5’ and 3’ noncoding sequences of 44 bp and 181 bp, respectively, and consisted of 840 bp that encoded for a prehormone of 204 amino acid (aa) residues. GH cDNA of the blue gourami (T. trichopterus; bgGH) and its deduced aa sequence had the same lengths as those of the pgGH, with nucleotide and aa identities of 97% and 99%, respectively. GH cDNA cloned from the dwarf gourami (Colisa lalia; dgGH) differed from both pgGH and bgGH. The identity of the dgGH cDNA nucleotides was 88%, compared to pgGH and bgGH. However, the identity of the deduced dgGH aa sequence was 97% when compared to bgGH and 96% when compared to pgGH. Nucleotides of GH cDNA of the fighting fish (Betta splendens; ffGH) had an identity of 82% to those of pgGH and bgGH, and 81% to the dwarf gourami. Higher identity was found among the aa sequences than among the nucleotide sequences. The identity of the cloned aa ffGH compared to bgGH, pgGH, and dgGH was 93%, 92%, and 91%, respectively.

Higher levels of GH mRNA were found in females in immature, vitellogenic, and mature stages than in males in various stages of gonadal development. No significant differences in the GH transcription level were found between immature and mature females and males. However, the mRNA level decreased significantly during sexual behavior in males. GH sequence and expression may be used as systematic markers for Belontiidae fish and possibly other fish.
Traditional Indian herbal extracts used in vitroagainstgrowthofthepathogenicbacteria–Aeromonashydrophila
Authors: Bhuvaneswari R. , Balasundaram C.
Published: February 2021

Crude ethanol extracts of Acalypha indica, Acorus calamus, Coleus aromaticus, Heliotropium indicum, and Indigofera aspalathoides were screened for antibacterial activity in vitro against the growth of the fish pathogenic bacteria, Aeromonas hydrophila. Terramycin, widely used to con- trol A. hydrophila in aquaculture, was used as a positive control. The herbs A. calamus and I. aspalathoides warded off the growth of the pathogen completely at minimum inhibitory concen- trations of 1.29 and 2.16 mg/l, respectively. A minimum bacterial concentration of 1.00 cfu occurred at concentrations of 0.77 mg/ml for A. calamus and 1.29 mg/ml for I. aspalathoides. The order of potency of the herbs in warding off growth of A. hydrophila in vitro was ranked: A. calamus, I. aspalathoides, C. aromaticus, A. indica, and H. indicum. The inhibitory potency of A. calamus and I. aspalathoides was significantly higher (p<0.05) than that of the positive control, indicating the potential of these herbs to replace antibiotics in controlling A. hydrophila infection.
Digestible energy in dietary sorghum, wheat bran, and rye in the common carp (Cyprinus carpio L.)
Authors: Degani Gad
Published: February 2021

The digestibility of protein, fats, carbohydrates, and energy in three feed ingredients (sorghum, wheat bran, and rye) in common carp, Cyprinus carpio, was studied using the chromic oxide method. Three experimental diets were tested. Each contained 52.5% of a basal diet and 47.5% of the test ingredient. The carbohydrate levels in the test ingredients ranged 65-83% and the pro- tein levels ranged 11-18%. Therefore, carbohydrates were the main energy source. Results showed that the digestibility of protein in rye (91.89%) was significantly higher (p<0.05) than in sorghum (71.86%) and wheat bran (80.64%), producing 12.4, 6.7, and 9.3 kJ/g digestible ener- gy, respectively. The lipid levels in the test ingredients were very low, 1-4%. Lipid digestibility was 79.84%, 76.71%, and 82.01% in rye meal, sorghum meal, and wheat bran, respectively.
Effects of energetic diets on growth, blood chemistry, and liver pathology of African catfish, Clarias gariepinus (Burchell 1822)
Authors: Yilmaz Erdal , Akyurt Ihsan , Mutlu Ekrem
Published: February 2021

The effects of isonitrogenous diets (350 g crude protein/kg diet) with different energy levels (10.85, 11.82, 12.73, 13.69, and 15.06 MJ dietary energy/kg feed) on growth, feed utilization, blood chemistry, and liver histopathology of African catfish, Clarias gariepinus, were investigat- ed to determine the optimum diet for this species. The diet containing 12.73 MJ digestible ener- gy/kg feed resulted in the best growth, blood parameters, and liver histology. Fish that consumed the 10.85 and 11.82 diets had similar weight gains, feed, and protein utilization as fish fed diets containing 13.69 or 15.06 MJ (p>0.05) but fish fed diets containing 13.69 or 15.06 MJ/kg had signs of hepatic lipidosis.
Effects of Short and Long Exposure to the Anesthetic 2-Phenoxyethanol Mixed with Ethyl Alcohol on Common Carp (Cyprinus carpio L., 1758) Fingerlings
Authors: Altun Tülay , Danabas Durali
Published: February 2021

Common carp fingerlings (Cyprinus carpio L., 1758; 7.70±0.4 g; 8.38±0.8 cm) were exposed to different concentrations of 2-phenoxyethanol mixed with pure ethyl alcohol (1:1) in an open sys- tem for a short (until induction of anesthesia) or long (48 h) duration, then transferred to clean water and maintained for 96 h. The effects of the anesthetic on induction time, anesthetic stage, opercular rate, recovery time, recovery stage, and mortality were observed. For short exposure, the most suitable concentrations were 0.8, 1, and 1.2 ml/l. For long exposure, transportation, and deep sedation and partial loss of equilibrium (anesthetic stages 2 and 3), the preferable con- centrations were 0. 4 and 0.6 ml/l. No mortality was observed at any concentration.
Ozone action on survival and storage life of live and chilled tilapia
Authors: Glatman L. , Sachs O. , Khanin Y. , Drabkin V. , Gelman A.
Published: February 2021

The effects of applying ozone treatment to live pond-raised tilapia on the survival of live fish and length of storage of chilled fish were evaluated according to sensory, chemical, physical, and bacteriological tests. Long-term low-level ozonation extended survival and improved the physi- cal state of live fish in a tank and may be feasible for use in fish markets to improve commercial quality of live fish. Ozone treatment of tilapia while still alive prolonged their storage life as chilled tilapia by 12 days (40%) and improved their quality when stored at 0°C but had little effect at 5°C. The improvement probably resulted from an initial reduction and prevention of growth of spoilage bacteria such as Pseudomonas fluorescens, Shewanella putrefaciens, and Aeromonas sobria. At 0°C, P. fluorescens was most sensitive to ozone, while Brevundimonas diminuta and Pseudomonas putida were not. The combination of ozone pretreatment and storage at 0°C appears to be a feasible means of prolonging the storage life of chilled tilapia.
Selective breeding of food size rainbow trout:Currentandfutureprospects
Authors: LaPatra Scott E. , Towner Richard H.
Published: February 2021

Rainbow trout (Oncorhynchus mykiss) are a valuable aquaculture production species in the USA where an average 25,000 tons per year of food size rainbow trout were produced during 1988- 2002. Clear Springs Foods, Inc., is one of the largest producers of aquacultured rainbow trout, producing 10,000 tons annually. Privately held by an employee owned trust, Clear Springs is a vertically integrated company from brood stock through egg production, feed manufacturing, farm operations, processing, and distribution. Clear Springs has a significant commitment to research and development. Selective breed- ing of rainbow trout is an important component of its R&D program. The current goals of the selective breeding program are to improve growth and disease resistance. To improve these traits, data are recorded on thousands of individuals each year. Growth data is collected at var- ious ages to determine which families and which individuals within each family have the best growth. To improve disease resistance, a portion of the progeny from each family are exposed to specific pathogens in a standardized challenge test. Currently, each family is tested for sur- vivability to infectious hematopoietic necrosis virus (IHNV) and Flavobacterium psychrophilum, the causative agent of bacterial coldwater disease (CWD) and rainbow trout fry syndrome (RTFS). Selection to improve growth began when the breeding program was initiated. The average weight of the odd-year generation group increased from 660 g at 328 days of age in 1991 to 921 g at 301 days in 2003. The average weight of the even-year group increased from 620 g at 328 days in 1992 to 866 g at 301 days in 2004. Selection to improve IHN resistance started with the 1994 generation. Using a standardized challenge test, IHN mortality decreased 25.8% in the odd-year generation group and 29.7% in the even. Growth is a moderately heritable trait that can be changed rapidly and economically with traditional quantitative genetic techniques. Disease resistance has much lower heritability and is more difficult to change. Better knowledge of spe- cific and general disease resistance mechanisms in trout would aid the industry in improving future stocks.
Genomic approaches to identifyingsex-determininggenesintilapia
Authors: Kocher Thomas D. , Lee Bo-Young , Cnaani Avner
Published: February 2021

Variation in sex determination mechanisms among the different tilapia species has been recog- nized for over 40 years. We have looked for associations between microsatellite DNA markers and sex in families from different species and strains of tilapia. We found that at least two dif- ferent linkage groups are involved in sex determination in this group of fishes. In two species, O. niloticus and T. zillii, we found evidence for male heterogamety with a major sex-determining locus on linkage group 1 (LG1). In two other species, O. aureus (Israeli strain) and O. karongae, we found evidence for female heterogamety with a major locus for sex determination on LG3. In O. aureus (Egyptian strain) and in O. mossambicus, loci associated with sex determination were found on both LG1 and LG3, and a complex mechanism of sex determination was detected. Physical mapping by fluorescence in situ hybridization (FISH) suggests that LG3 corresponds to the largest chromosome pair, and that there is recombination suppression in the sex determina- tion region. The sex-determining region in O. niloticus has been mapped to an 11cM region between markers GM201 and UNH995 on LG1. A BAC contig containing UNH995 was identi- fied and several BACs in the contig were end- or shotgun sequenced. BLAST analysis of these sequences identified Tetraodon chromosome 5 as the homolog of tilapia LG1. Additional SNP and microsatellite markers were developed from published cichlid ESTs and the order of these markers is consistent between tilapia and Tetraodon. We have narrowed the sex-determining region to a 2.6cM interval which corresponds to a 400 kb region of Tetraodon chr5. We are com- pleting genetic and physical maps across this region in order to identify the gene(s) responsible for sex determination in this species.
Effects of genetic and environmental factors on sex differentiation in the European sea bass (Dicentrarchus labrax)
Authors: Ron Tetsuzan Benny
Published: February 2021

One of the major problems in the mariculture of the commercially important European sea bass, Dicentrarchus labrax, is that females grow 20-50% more rapidly than males. For that reason, farmers are interested in developing female monosex populations. Studies on evolution, genet- ics, and physiology have been conducted during the last decade to solve this problem. This review summarizes the latest data related to the effects of evolution, genetics, physiology, and environment on sex determination and differentiation in the European sea bass.
Genetic basis of sex determination in fishes: Searching for master key regulator genes in the sex determination pathway of tilapias
Authors: Shirak Andrey , Seroussi Eyal , Zilberman Noam , Hulata Gideon , Ron Micha , Cnaani Avner , Kocher Thomas D.
Published: February 2021

Recent results show a striking similarity in the dynamics of expression of gonad differentiation regulators in zebrafish and mammals. Candidates for the role of master key regulators (MKRs) in tilapia were selected, based on three concepts established in the literature for non-mammal species. These three concepts are: (a) MKRs are DM-proteins or their close downstream/ upstream partners in the sex determination pathway, (b) MKRs are genes working just upstream of aromatase in the sex determination pathway, or the aromatase itself, and (c) MKRs are homologs of mammal genes which are close partners of SRY (“missing” in non-mammal verte- brates), mostly belonging to the SOX family. Coding sequences of putative genes were searched in cichlid (TIGR) and general (NCBI) databases, and in the tilapia gonad EST library (RBEST). Primers in two adjacent exons were designed, based on predicted exon-intron boundaries for each of 11 selected genes. Amplified segments of the targeted genes in two purebred tilapia species were sequenced. Seven SSLP and four SNP-based markers were identified in the can- didate genes for MKRs of sex determination and mapped to the tilapia genetic map using geno- type data of 76-90 individuals of the F2 mapping family. The mapping positions of the selected genes relative to previously reported QTL regions for sex determination are discussed.
Aspects of comparative genomics in the gilthead seabream, Sparusaurata
Authors: Kotoulas Georgios , Consortium BRIDGEMAP
Published: February 2021

Genome projects for new fish species are found in a transitional period during which resource development and meaningful com- parative genomics analysis or use of any other comparative approach must be done in parallel. In new species, full sequencing is still prohibitive due to the high cost of vertebrate genome sequencing and the fact that present technology is time consuming. However, in the case of the few model species whose research is pioneering and where huge progress has been made on developmental, physiological, behavioral, and genomic levels, knowledge integration is in a process of rapid change. These reasons may explain why a general strategy to facilitate the choice of tar- get species and the kind of developments needed has not yet been adopted. In such an environment,BRIDGEMAP ,theEuropean gilthead seabream genome project, was com- pleted in December 2005. This was one of the first genome projects for a non-model fish of aquaculture interest.
Transcriptome characterization through the generation and analysis of expressed sequence tags: Factors to consider for a successful EST project
Authors: Liu Zhanjiang
Published: February 2021

Sequencing of expressed sequence tags (ESTs) has been one of the primary techniques used for transcriptome analysis in a wide spectrum of species including those utilized for aquaculture. However, many researchers are still unfamiliar with the many genome applications and byprod- ucts of EST analysis, and they often regard ESTs as only short random sequences. Additionally, lack of cDNA library normalization, project planning, and quality control have often restricted the value of EST resources created in many laboratories. This review aims to address these issues by providing information on the construction of normalized cDNA libraries for efficient generation and analysis of ESTs and by highlighting the significance of EST analysis for the genome research of species lacking a sequenced genome. A successful EST project can provide the sequence tools needed for not only gene discovery, but also for physical, linkage and compara- tive mapping, analysis of alternative splicing and gene duplication, and microarray development.
Production of recombinant hormones and growth factors for use in aquaculture
Authors: Funkenstein Bruria
Published: February 2021

Progress in recombinant DNA technology and development of new expression systems has provided valuable means to produce large quantities of hormones and growth factors from various fish species that otherwise required sacrifice of enormous numbers of fish to obtain only small amounts of the native protein. The motivation to produce recombinant hormones and growth factors for application to fish culture can be attributed to (a) the low amounts of pep- tides in producing tissues available for purifica- tion and characterization by classical methods, i.e., follicle stimulating hormone (FSH = GtH-I) in the pituitary or insulin-like growth factor-I (IGF-I) and IGF-II in the liver, (b) the similarity in chemical structure between two hormones that does not permit efficient separation (FSH and LH = GtH-II), (c) the need for large quanti- ties of hormones for growth enhancement by growth hormone (GH), and (d) interest in studying structure/function relationships, i.e., single or multiple amino acid deletion, amino acid substitution, etc.
Practical use of cytogenetics in fish biology and aquaculture
Authors: Gorshkov Galina
Published: February 2021

The reviewed information was accumulated from our current and earlier cytogenetic studies on various commercially important fish species. The major emphasis of the review is to show in which way classical cytogenetics can be practically used for basic and applied research in fish biology and aquaculture.
A review of ploidy manipulations in aquaculture: The Israeli experience
Authors: Rothbard Shmuel
Published: February 2021

Ploidy manipulation was introduced to Israel at the beginning of the 1980s. To improve existing methods, Israeli fish centers conducted intensive research in this field for more than two decades. Chromosome-set technology was adapted for ten fish species and varieties, including two marine fish. Presently, though methodology achievements are remarkable, practical imple- mentation is applicable only for the common carp. The aim was to integrate gynogenesis and androgenic sex-reversal to generate neomales with special genetic traits in this economically important species that is extensively cultured in Israel. Carp neomales can serve as parents for production of fast-growing all-female populations. This paper describes ploidy manipulation progress and activities carried out in four Israeli fish centers. Future objectives include (a) imple- mentation of the existing know-how to produce tilapia YY-males as broodfish for producing male- monosex populations, (b) dissemination and promotion of export to foreign markets of the advantageous female triploid grass carp and black carp, (c) continuation of genetic work with marine fish to develop breeds that could be advantageous for mariculture, and (d) reconsidera- tion of the ploidy-manipulated koi as a genetic tool to be utilized to facilitate gene-mapping in carps.
History of catfish breeding and its application in the United States: Lessonstobelearned?
Authors: Dunham Rex A.
Published: February 2021

The history of selective breeding in the US catfish industry is reviewed. The failures and suc- cesses of technology and germplasm transfer for catfish genetic enhancement are discussed.
Effects of a Glucan from the Edible Mushroom (Pleurotus florida) as an Immunostimulant in Farmed Indian Major Carp (Catla catla)
Authors: Kamilya Dibyedu , Joardar Siddhartha N. , Mal Bimal C. , Maiti Tapas K.
Published: February 2021

The purpose of this study was to determine the effects of a dietary mushroom glucan on the non- specific immune responses and disease resistance of the Indian major carp, Catla catla. Glucan was extracted from farm-raised edible mushrooms (Pleurotus florida). The glucan was fed to test animals for two weeks at 0.5 g or 1 g/kg feed. Afterward, the fish received the control diet for another four weeks. Non-specific immune responses were measured at the end of the two-week experimental feeding (week 0), two weeks later (week 2), and four weeks later (week 4). Control and test fish were challenged by intraperitoneal injection of the fish pathogenic bacterium, Aeromonas hydrophila, seven days after the two-week experimental feeding period. Mortality was observed and the relative percent survival was calculated. In the 0.5 g treatment, significant enhancement (p<0.05) in superoxide anion production was observed at weeks 0 and 2. In the 1 g treatment, activity was enhanced only at week 2. Both concentrations significantly increased phagocytosis at weeks 0 and 2 and bactericidal activity at weeks 2 and 4 (p<0.05). Alternative complement pathway activity was unaltered by either treatment (p>0.05), but lysozyme activity was raised at weeks 2 and 4 in the 0.5 g treatment and at week 2 in the 1 g treatment. Both con- centrations significantly enhanced relative percent survival.
Isolation and Characterization of Bacteria Associated with Cultured Penaeus monodon Affected by Loose Shell Syndrome
Authors: Jayasree L. , Janakiram P. , Madhavi R.
Published: February 2021

Seventy shrimps affected by loose shell syndrome (LSS), a major disease causing mass mor- talities in shrimp farms in north coastal Andhra Pradesh (India), were subjected to bacteriologi- cal analysis. Total bacteria and vibrio counts in the hemolymph were estimated; bacteria were isolated and identified; their pathogenicity and drug sensitivity were studied. Total bacteria ranged 1.28 x 102 to 5.8 x 105 cfu/ml while Vibrio ranged 0.7 x 102 to 2.1 x 105 cfu/ml. Six species of Vibrio were isolated from the hemolymph including V. harveyi, V. alginolyticus, V. para- haemolyticus, V. anguillarum, V. splendidus, and V. vulnificus. Vibrio harveyi was the most dom- inant with a prevalence of 100%. It was also the most virulent with a low LC50 value of 1 x 103 cfu/g. Histopathological study revealed changes typical of bacterial septicemia including invasion of bacteria into the hemolymph, formation of granulomas in the hepatopancreas and other organs, and extensive proliferation of connective tissue and necrosis of the hepatopancreas, gills, and ovarian tissues. Sensitivity to 22 antibiotics was tested. Most of the bacterial isolates were highly sensitive to chloramphenicol, ciprofloxacin, and norfloxacin while V. harveyi was resistant to as many as 16 antibiotic drugs including chloramphenicol.
Effects of Lecithin on Cholesterol Digestibility in the Prawn, Artemesia longinaris (Crustacea, Penaeidae)
Authors: Haran Nora S. , Fenucci Jorge L.
Published: February 2021

Cholesterol and dietary phospholipids are important to the growth and survival of crustaceans. Soy lecithin enhances cholesterol solubilization while phosphatidylcholine transfers cholesterol from the hepatopancreas to the hemolymph. To study the influence of dietary lecithin on digestibility and transport of cholesterol to the hemolymph in Artemesia longinaris, diets with dif- ferent levels of supplemental cholesterol (0.5, 1, 1.5, and 2%) and soy lecithin (0, 0.5, 1, and 2%) were fed to prawns for two weeks. The diet containing the lowest level of cholesterol (0.5% ) and lecithin (1%) resulted in the lowest apparent digestibility of cholesterol. The diets containing 2% cholesterol and 1% or 2% lecithin resulted in the highest hemolymph cholesterol contents. There was a linear relationship (r = 0.832; p<0.01) between hemolymph cholesterol and the amount of lecithin in the diet. There were no significant differences between treatments in cholesterol con- tents in the hepatopancreas. In a second 6-week experiment, diets containing 1.5% cholesterol significantly improved weight gains, regardless of the lecithin content. Survival rates did not dif- fer among treatments. Hence, the efficacy of cholesterol does not seem to be related to dietary inclusion of lecithin.
Alterations in Hematological Parameters of Rainbow Trout (Oncorhynchus mykiss) Exposed to DDVP
Authors: Atamanalp Muhammed , Angis Simay , Oguzhan Pinar , Aksakal Ecrument
Published: February 2021

The aim of this study was to assess the effects of a sublethal dose (1.6 mg/l) of DDVP (dichlor- vos) on hematological parameters of rainbow trout (Oncorhynchus mykiss) after 28 days of exposure. The DDVP caused increases in the red and white blood cell counts, hemoglobin, ery- throcyte sedimentation rate, mean corpuscular volume, and mean corpuscular hemoglobin con- centration (MCHC). On the other hand, it decreased thrombocyte (Plt), hematocrit (packed cell volume), and mean corpuscular volume. The only statistically significant differences between exposed and unexposed fish were in white blood cell count and MCHC.
Effects of Probiotics and Spirulina on Survival and Growth of Juvenile Common Carp (Cyprinus carpio)
Authors: Ramakrishnan C. Muthu , Haniffa M.A. , Manohar M. , Dhanaraj M. , Arockiaraj A. Jesu , Arunsingh S.V.
Published: February 2021

A 45-day feeding trial was conducted to investigate the effects of probiotics and spirulina on sur- vival, growth, feed conversion ratio (FCR), protein efficiency ratio (PER), and total heterotroph- ic microbial count in common carp (Cyprinus carpio). Two probiotic organisms (the bacteria Lactobacillus acidophilus and the yeast Saccharomyces cerevisiae) and a single cell protein (Spirulina maximus) were incorporated into diets at concentrations of 1%, 2%, or 3%. The con- trol diet contained no supplement. Spirulina maximus at 3% produced the best and statistically significant (p<0.05) survival, growth (3.69±0.10 g), specific growth rate (1.27±0.02%/d), FCR (0.71±0.08), and PER (1.96±0.03). In general, L. acidophilus produced better growth than S. cerevisiae. The highest FCR (1.93±0.05) was obtained in the control. The total heterotrophic microbial count was highest in S. cerevisiae treatments, followed by L. acidophilus and S. max- imus. The present investigation shows that incorporation of a probiotic or spirulina in diets for common carp results in increased growth rate.
Effect of Dietary Vitamin E on Growth, Fecundity, and Leukocyte Count in Goldfish (Carassius auratus)
Authors: James Raja , Vasudhevan Iyyadurai , Sampath Kunchitham
Published: February 2021

The effects of different levels of dietary vitamin E (0, 100, 200, 300, and 600 mg/kg diet) on growth, gonad weight, fecundity, and leukocyte count were studied in goldfish (Carassius aura- tus) for 120 days. Fish fed the 300 mg vitamin E/kg diet had the best feeding rate, weight gain, and specific growth rate. Fish fed the control diet lacking vitamin E began to develop gonads on day 60 and spawned only once, while those fed diets containing vitamin E began to develop gonads on day 40 and spawned twice. Females fed the 300 mg vitamin E/kg diet had signifi- cantly (p<0.01) heavier gonads and a higher number of eggs with better hatchability than those fed other diets. The second spawn was significantly (p<0.01) more prolific than the first in all groups. Egg weight and diameter and larvae weight and length were significantly (p<0.05) high- er in fish fed 300 mg vitamin E than in fish fed the control diet but did not differ from other vita- min E treatments. Lymphocyte and monocyte populations were highest in fish fed 300 mg vita- min E. Thus, 300 mg vitamin E/ kg diet is the optimum level for improving reproduction and immune response in C. auratus. The probable mechanism for the action of vitamin E on growth and reproduction is discussed.
Survival and Growth of Captive Reared Juvenile Seahorse (Hippocampus kuda) Fed Live Feeds and Fishmeal
Authors: Thangaraj M. , Lipton A.P.
Published: February 2021

Pond and aquarium keeping of seahorse (Hippocampus kuda) is challenging because of their feeding habits. Although seahorse is a purely active predator, we successfully raised laboratory- produced young on inert feed and evaluated the effects of readily-available cost-effective food items on their growth and survival. Two-month old laboratory bred juveniles were fed live Artemia, live Mysids, minced fishmeal, or a combination of Artemia and Mysids (1:1). Juveniles fed the combination diet reached the highest wet weight (1.93±0.31g), specific growth rate (2.21±0.07), and survival (96±3.0%), significantly (p<0.05) higher than juveniles fed fishmeal (1.42±0.12 g, 2.08±0.03, and 76±3.0%, respectively). Although there were insignificant differences in growth and survival between juveniles fed the combination and those fed Mysids or Artemia, the combi- nation diet was best. This easily available feed can be used in ornamental aquaria.
Optimal Dietary Protein Levels in Juvenile Electric Blue Cichlid (Sciaenochromis fryeri)
Authors: Gullu Kenan , Güroy Derya , Celik Ihsan , Tekinay Adem
Published: February 2021

A feeding trial was conducted to determine the dietary protein requirement of juvenile electric blue cichlids (Sciaenochromis fryeri). Groups of fish (0.50±0.01 g) were fed one of four isocaloric diets containing protein levels ranging 35-50% for 12 weeks. According to the broken-line model, the dietary protein requirement was estimated as 38.8%. The feed conversion ratio ranged from 1.73 in the 50%-protein group to 2.16 in the 35% group. There were statistically significantly dif- ferences in feed intake and protein efficiency ratio. In general, the protein efficiency ratio decreased as the dietary protein level increased. For optimum growth, feed conversion, and pro- tein utilization, a diet containing 39-40% protein, 11% crude lipid, and 20.7 MJ gross energy/kg diet is recommended for juvenile S. fryeri.
Comparison of Periphyton Grown on Different Substrates as Food for Organic Tilapia Culture
Authors: Milstein Ana , Peretz Yakov , Harpaz Sheenan
Published: February 2021

Regulations regarding organic tilapia culture result in increased feed costs. To reduce such costs, experiments were conducted to enhance the natural production of periphyton, on which tilapia feed. Strips of substrates of different textures and colors were placed in the water column of tilapia culture ponds to induce periphyton growth. Some strips were placed in cages to protect them from fish grazing and some where placed in the open pond, accessible to the fish. Periphyton development was evaluated by the contents of chlorophyll, dry matter (DM), and ash free dry matter (organic matter) and by an autotrophic index. The first experiment tested growth on substrates of different textures including natural (palm leaves) and artificial (agricultural nets, plastic surfaces) materials. The second experiment tested the effect of different colored nets. The differences between periphyton grown in cages and in the open pond indicate that tilapia grazed on the periphyton. Palm leaves decomposed too quickly to be of practical use in large- scale aquaculture. Periphytic material seemed to be more easily dislodged from smooth plastic substrates than from rough nets, changing the structure of the residual attached periphyton. Growth was greater on nets with a fine mesh (5.3-9.6 mg/cm2 DM) than with a coarse mesh (3.7- 4.0 mg/cm2 DM) or on smooth plastic surfaces (1.4-2.6 mg/cm2 DM). The color of the substrate did not affect the chlorophyll content of periphyton but did affect its dry and organic matter con- tent. The white substrate had 40% more dry matter (11.5 vs 7.9-8.2 mg/cm2) and 50% more ash free dry matter (2.1 vs 1.4 mg/cm2) than the blue and black substrates.
Screening Cage Culture Fish Species for Organic Chlorinated Pesticide and Polychlorinated Biphenyl Residues in Turkey
Authors: Koc Feride , Gurel Yasemin , Yigit Yusuf , Atamanalp Muhammed , Kursad Yavuz , Kisa Fikrullah
Published: February 2021

Organic chlorinated compounds (aldrin, α-endosulfan, β-endosulfan, 2,4’-DDT, and 4,4’-DDE) and polychlorinated biphenyles (PCB28 and PCB52) were screened in fish culture cages off the Aegean Coast of Turkey. Sea bass (Dicentrarchus labrax) and sea bream (Sparus aurata) were randomly selected from three coastal areas during June-December 2004. Samples of 114 fish were analyzed by gas chromatography (GC) with an electron capture detector and GC-mass spectrometry (GC-MS). No residues exceeding limits established by the European Union Directive were detected. However, 4,4’-DDE was found in 2.63% of the samples. The amounts of residues in all positive samples were lower than the maximum tolerance limits (0.2-1 mg/kg) accepted by the EU Directive. Contamination levels varied with species, ranging 18-200 ng/g wet weight. Other chemicals were not detected in fish samples.
Detection and Identification of Fish Pathogens: What is the Future?
Authors: Frans I. , Lievens B. , Heusdens C. , Willems K.A.
Published: February 2021

Fish diseases pose a universal threat to the ornamental fish industry, aquaculture, and public health. They can be caused by many organisms, including bacteria, fungi, viruses, and protozoa. The lack of rapid, accurate, and reliable means of detecting and identifying fish pathogens is one of the main limitations in fish pathogen diagnosis and disease management and has triggered the search for alternative diagnostic techniques. In this regard, the advent of molecular biology, especially polymerase chain reaction (PCR), provides alternative means for detecting and iden- tifying fish pathogens. Many techniques have been developed, each requiring its own protocol, equipment, and expertise. A major challenge at the moment is the development of multiplex assays that allow accurate detection, identification, and quantification of multiple pathogens in a single assay, even if they belong to different superkingdoms. In this review, recent advances in molecular fish pathogen diagnosis are discussed with an emphasis on nucleic acid-based detec- tion and identification techniques. Major features and applications of current predominant meth- ods and promising methods likely to impact future fish disease control and prevention are out- lined.
Experimental commercial growout of Penaeus semisu/catus (Decapoda: Penaeidae)
Authors: Turkmen Gurel
Published: February 2021

Sea bass and sea bream have become almost synonymous with marine aquaculture in Turkey, indicating the level of commercial success they have attained during the last two decades. However, to diversify an industry overly dependent on these two products, as well as to provide the market with an additional commodity, other species are being considered for future culture. In the present study, commercial culture of Penaeus semisulcatus on the Aegean coast of Turkey was evaluated. In 150 days, the shrimp grew from 0.03 g to 18.72 g, with a mean daily growth rate of 0.125 g. The food conversion rate and specific growth rate were 2.26 and 2.34, respectively. Production reached the equivalent of 2880 kg/ha with a survival of 77%. While pro- duction results and shrimp weights were considerable, to obtain larger shrimp of greater value, early maturation and spawning in a nursery system must be included in conjunction with the growout ponds.
Impact of water temperature on growth in cobia, Rachycentron canadum, cultured in cages
Authors: Vu Shyi-Liang , Ueng Ping-Sheng
Published: February 2021

Temperature is a major factor affecting fish growth in natural environments. The relationship between water temperature and growth rate in cobia, Rachycentron canadum, was examined at a fish farm in Penghu, Taiwan. Six cages, stocked with 300 fish each, were used in the year-long experiment. Growth rate was monitored by sampling 30 fish from each cage every month. Water quality was optimum throughout the experiment. Fish were fed commercial fish food to satiation twice a day. Cobia grew 0.84%/day in summer (March-September) and 0.41%/day in winter (October-February). The slowest growth occurred in late December at temperatures of 15.0- 16.5°C and the fastest during summer at temperatures above 28°C.
Effects of dietary androstenedione concentration on growth of tilapia fry (Oreochromis aureus Linnaeus)
Authors: Turan Funda , Gurlek Mevlut , Turan Cemal
Published: February 2021

The effects of androstenedione on the growth, body composition, and survival of tilapia (Oreochromis aureus) fry were examined. Diets were supplemented by one of three androstene- dione concentrations (50, 100, or 200 mg/kg) for twelve weeks. The growth rate significantly increased in fish fed 50 mg androstenedione per kg compared to the control (p<0.01) but decreased dramatically at concentrations beyond 50 mg/kg. The specific growth rate, protein efficiency ratio, and food conversion ratio were significantly better in the 50 mg/kg group than in the other groups. Crude protein and survival at all androstenedione levels did not significantly differ from those of the control but lipid content dropped with 100 mg/kg supplementation.
Prevalence and intensity of ectoparasites in rainbow trout (Oncorhynchus mykiss) from larvae stage to market size in Turkey
Authors: Ogut Hamdi , Akyol Abdurrezzak
Published: February 2021

Rainbow trout (Oncorhynchus mykiss) from three Turkish farms were sampled monthly from May 2003 to June 2004 to determine ectoparasite seasonality, prevalence, and intensity. Smears of gills, skin, and fins of 1260 larvae to market-size fish were examined. Six protozoans and one monogenean were found: Ichthyobodo necator, Chilodonella piscicola, Ichthyophthirius multifil- iis, Gyrodactylus sp., Trichodina claviformis, Apiosoma piscicolumn, and Hexamita salmonis. The first three were found mainly in fry and all except I. multifiliis occurred in low temperatures from late fall through early spring. Infections of C. piscicola and Gyrodactylus sp. were persis- tent and T. claviformis was found for the first time on rainbow trout in the area.
Effects of Early Weaning on Growth and Digestive Enzyme Activity in Larvae of Sea Bass (Dicentrarchus labrax L.)
Authors: Süzer Cüneyt , Firat Kursat , Saka Sahin , Karacaogian Arif
Published: February 2021

The influence of early weaning on digestive enzymes, growth, and survival in sea bass larvae were investigated. Larvae were reared in a closed sea water system and first fed Artemia nau- plii eight days after hatching. Three weaning periods were compared by introducing a micropar- ticulate diet on day 15, 20, or 25. The control continued to be fed only Artemia. The lowest growth and survival rates were obtained in the 15-day group while the highest were in the 25- day group. After weaning, protease activities (trypsin, chymotrypsin, elastase, pepsin) dropped in all groups, indicating malnutrition. Amylase activity slightly increased in all experimental groups due to the higher starch content in the microparticulate diet than in Artemia and the absolute and relative lipid contents were lower in groups fed the microparticulate diet. Lipase activity suddenly dropped after weaning but slightly rose from day 35 until the end of the exper- iment (day 40). Due to decreased larvae development, survival, and digestive enzyme activity, weaning at 20 days after hatching, synchronous to formation of the stomach and enzymatic activity, is strongly recommended.
Rematuration of Spent Macrobrachium rosenbergii Female Broodstock through Dietary Manipulation and Eyestalk Ablation
Authors: Murmu Khuntia , Sahu N.P. , Mallik S.K. , Reddy A.K. , Kohli M.P.S.
Published: February 2021

The single or combined effects of artificial feed and eyestalk ablation on gonadal maturation of spent Macrobrachium rosenbergii female brooders was studied in 48 females. Significant differ- ences in percent weight gain, food conversion ratio, specific growth rate, gonado-somatic index, number of molts, molting interval, and ovarian development stages were observed. The highest numbers of molts and shortest molting intervals were found in eyestalk-ablated groups while higher percent weight gains were obtained in non-ablated groups. Groups fed formulated feed registered lower percent weight gains and higher FCRs than groups fed natural feed (clam and squid meat). Females in immature stages were found only in non-ablated groups while the only ovigerous females were found in the ablated group fed formulated feed. In short, unilateral eye- stalk ablation together with properly formulated feed (46.1% crude protein) could induce gonad maturation of spent female Macrobrachium rosenbergii brooders during the non-monsoon sea- son.
Antigenic Characterization of Outer Membrane Protein of Aeromonas sobria Isolated from Goldfish (Carassius auratus L.)
Authors: Mali P. , Maji S. , Joardar S.N.
Published: February 2021

Aeromonas sobria, along with A. hydrophila, has frequently been reported as a causative agent of motile aeromonas septicemia (MAS) in fish and other aquatic organisms. Currently, there are no precise tools to diagnose or vaccinate against this disease. The aim of the present study was to fractionate and characterize the outer membrane protein (OMP) antigen of A. sobria by sero- logical and cellular techniques so as to identify immunoreactive molecules that might be useful in preparing immunodiagnostic and/or immunoprophylactic tools against A. sobria infection in goldfish. Eight fractions were isolated from the crude OMP antigen using sephacryl S-200 and DEAE-cellulose chromatography. The highest seroreactivity was observed in the gel-permeated protein G1 which had an optical density (OD) of 0.72 nm, higher even than that of the crude OMP antigen, 0.63 nm. The serodiagnostic potential of G1 was assessed by using dip-stick ELISA. The in vitro goldfish lympho-proliferation ability of the fractionated antigen, G1A3, was higher than of all the other fractionated antigens and the crude OMP. Therefore, fractionated antigen G1 (molecular wt 42-67 kDa) and G1A3 (molecular wt 45-47 kDa) should be further studied in immunodiagnostic and/or immunoprophylactic preparations for A. sobria infection.
Diet-Influenced Performance of Juvenile Common Carp (Cyprinus carpio L.) after Experimental Aeromonas Infection
Authors: Witeska Malgorzata , Kozinska Alicja , Wolnick Jacek , Sikorska Justyna , Kaminsaki Rafai , Pruska Anna
Published: February 2021

The effects of two diets, SGP 493 (Aller Aqua, Denmark; SGP) and chironomid larvae (Katrinex, Poland; CHI), on juvenile carp survival and hematological values after subcutaneous infection with Aeromonas veronii bt. sobria (strain K144) were studied. All infected fish developed skin ulcers and both groups developed anemia, i.e., a severe reduction in hemoglobin content with- out a decrease in red blood cell count and a minor decrease in hematocrit. There were higher levels of hematocrit, hemoglobin, and mean cell hemoglobin in the CHI group at the beginning of the infection, together with a slightly higher erythropoietic potential. At the end of the experi- ment, partial recovery of hemoglobin levels took place. The SGP diet induced considerable leukocytosis in healthy fish, which did not enhance their resistance to the infection. Leukopenia, lymphopenia, and reduced phagocyte activity took place in all infected fish. Survival 15 days after injection was 50% in SGP and 63% in CHI, suggesting that fish fed natural food were slight- ly less susceptible to Aeromonas-induced anemia even though feeding natural food or SGP did not significantly affect the performance of infected fish.