bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative gene and QTL mapping in aquaculture species
Authors: Thorgaard Gary H. , Nicholas Krista M. , Phillips Ruth B.
Published: February 2021

Mapping genes and quantitative trait loci (QTLs) is of fundamental and applied interest in aquaculture species. Such studies can pro- vide essential information about rates and patterns of evolutionary change and may pro- vide tools which can be used in marker-assist- ed selection (MAS; e.g., Groenen et al., 2000). Mapping typically involves producing divergent crosses and analyzing segregation patterns in the offspring of hybrids between the divergent crosses. The more divergent the cross is, the greater the potential for finding useful marker and trait differences that can be mapped. The basic goal of mapping is to understand the position of loci on chromo- somes and how the positions change during evolution. The applied goal of mapping is to understand the position of loci associated with phenotypic traits which could be important in breeding programs. Correspondingly, QTL mapping seeks to identify the number and location of loci associated with phenotypic traits (e.g., Mackay, 2001; Mauricio, 2001; Burt and Hocking, 2002; Erickson et al., 2004) while applied QTL studies seek to identify candidate genes or markers for use in MAS.
Transgenic fish – where we are and where do we go?
Authors: Dunham Rex A. , Liu Zhanjiang
Published: February 2021

Transgenic fish have been developed that have improved growth, color, disease resistance, sur- vival in cold, and body composition, and produce pharmaceutical proteins. Transgenes elicit pleiotropic effects, some positive and some negative. In general, transgenic fish appear to have lower fitness than controls and pose little environmental risk, but this research is not fully con- clusive. Transgenic zebrafish with altered coloration have been commercialized and growth hor- mone transgenic salmon, carp, and tilapia are near commercialization. To enhance commer- cialization and minimize environmental risk, additional technologies such as transgenic steriliza- tion need to be developed. Genomic research has produced an abundance of molecular genet- ic information including many genes for consideration for gene transfer, highly regulated gene promoters, and knowledge about their expression and function. Functional genomics analysis should be applied in the future to enhance the capacity and versatility of transgenic technology.
Use of molecular tools for research and improvement of aquaculture stocks
Authors: Hallerman Eric M.
Published: February 2021

Development of molecular genetic markers provides aquaculture with tools for a number of research and practical applications. Genetic marking of experimental groups allows their evalu- ation in the same rearing units, increasing statistical power within limited research infrastructure. Parentage can be inferred for individuals in mixed-progeny groups, quantifying the contributions of individual parents and supporting the estimation of sire and dam effects. Building upon parent- age assignment, walk-back selection entails retention of the best members of each family as broodstock for the next generation. Molecular markers can be used to detect the segregation of quantitative trait loci (QTL) and knowledge of such linkages can be used for marker-assisted selection. Gene expression profiling can identify genes affecting traits of interest, providing can- didates for QTL or functional analysis. Purposeful genetic marking can be used to identify pro- prietary stocks, marketed products, and fish out-planted or escaping into natural ecosystems. Although each application has been demonstrated, genetic markers are not routinely used in commercial aquaculture. The limited practical application can be explained by the limited devel- opment of broodstocks for most aquaculture species, the small size and limited scope of most aquaculture operations, and the costs of genetic screening.
Practical genetics in Israeli mariculture: History and present status
Authors: Gorshkov Sergei
Published: February 2021

The aim of this review is to show the progress and achievements made to date in the selective breeding of cultured marine fish in Israel. The National Center for Mariculture (NCM) in Eilat was the first scientific organization to determine that a long-term selective breeding program is the key strategy for genetic improvement of commercially important marine fish. The main objective of the program is the development of genetically improved strains. The immediate practical goal is to improve the profitability of national mariculture through growth improvement in the gilthead sea bream (Sparus aurata). In this species, due to reproductive constraints that limit the prospects for family selection, mass selection was found to be the most practical tool for growth improvement. Currently, the selective breeding program for sea bream consists of several selected lines. Four cycles of mass selection for growth have been completed in commercial pro- duction environments. Mass selection and crossbreeding are integrated in the program. In the Eilat hatchery sea bream strain, a recessive deleterious Mendelian mutation (named “ebony”) was isolated by classical crossing experiments. A method was developed to use ebony for genetic protection of selected sea bream strains from unlicensed reproduction and propagation. Interspecific hybridization, chromosome set manipulation, and cytogenetic and sex control tech- niques were also applied; some were shown to be promising tools for short-term genetic improvement. In general, the NCM selective breeding program for sea bream showed that genetic gain for growth and faster economic return can be achieved within a “reasonable” time span of 10-12 years. The program is supervised by the Genetics and Physiology Department of the NCM. Presently, most Israeli commercial mariculture is using genetically improved strains of sea bream and newly domesticated strains of sea bass (Dicentrarchus labrax).
Effects of Betaine Supplementation in Plant Protein Based Diets on Feed Intake and Growth Performance in Rainbow Trout (Oncorhynchus mykiss)
Authors: Tiril Serap Ustaoglu , Alagil Fikret , Yagci Feraye Berkay , Aral Orhan
Published: February 2021

The effects of betaine supplementation on feed intake and growth performance in rainbow trout fed a plant-protein based diet were evaluated. Triplicate groups of rainbow trout (130 g) were fed the plant-protein basal diet, the basal diet with 1.5% betaine supplementation, or a fishmeal-based diet (control) for 80 days. Feed intake was significantly better (p<0.05) in fish fed the betaine-sup- plemented diet (161.2 g/fish) than in fish fed the basal diet (131.6 g/fish) and not significantly dif- ferent from fish fed the control (152.8 g/fish). Weight gain was significantly higher (p<0.05) in fish fed the betaine-supplemented diet (117.0%) than in fish fed the basal diet (95.9%). Results indi- cate that, in diets based on plant proteins that often have low palatability, betaine supplementation may improve feed acceptability and growth performance in rainbow trout.
Reproductive Characteristics and Egg Development in Flounder (Pleuronectes flesus luscus) in the Southern Black Sea
Authors: Sahin Temel , Gunes Ardinc , Aydin IIhan , Polat Mamza
Published: February 2021

Spawning time, total fecundity, egg size, fertilization and hatching rates, and egg development of the flounder, Pleuronectes flesus luscus, were investigated in six wild female broodstock (mean wt 394.4±226.8 g). Spawning lasted 33 days from December 29 to January 30. Mean total fecundity was 171.4±109 x 103 eggs per female. Newly ovulated eggs were spherical and buoyant, with a diameter of 1.075-1.213 mm (avg 1.156±0.025 mm), a colorless transparent chorion, a slightly yellowish unsegmented yolk, and a narrow perivitelline space, without an oil globule. Fertilization and hatching rates were 17.2±15.7% and 51.5±27.6%, respectively. Hatching occurred after 117 h of incubation at 9.8-11oC. There were variations in egg size between batches, with the size tending to decrease during the spawning season (p<0.05).
Incorporation of Soybean Meal and Hazelnut Meal in Diets for Black Sea Turbot (Scophthalmus maeoticus)
Authors: Ergün Sebahattin , Yigit Murat , Türker Ali , Harmantepe Burcu
Published: February 2021

The effects of soybean and hazelnut meals as partial replacements of fishmeal were studied in Black Sea turbot (Scophthalmus maeoticus). Juvenile fish (mean 26 g) were fed six isoenergetic (19.1±0.18 kJ/g diet) and isonitrogenous (511±0.48 g protein/kg diet) diets for 60 days. The con- trol diet contained fishmeal as the sole protein source. In two of the six experimental diets, soy- bean meal replaced 20% and 35% of the fishmeal. The other three diets contained 65% fishmeal plus soybean and hazelnut meal at ratios of 25/10, 15/20, 5/30. There was no significant differ- ence (p<0.05) in growth performance between the groups fed the diet containing 20% soybean meal and those fed the control diet. Fish fed the 10% or 20% hazelnut meal diets had similar results as fish fed the diet containing 35% soybean meal. Growth performance, feed utilization, protein efficiency, and nitrogen retention were significantly lower in the group fed the 30% hazel- nut diet. Total nitrogen excretion and retention were similar in all groups except the 30% hazel- nut group. Results indicate that soybean meal can replace up to 20% of the fishmeal without causing reduction in growth performance, nutrient utilization, or nitrogen retention and that hazel- nut meal can be incorporated with 20%, but not 35%, soybean meal at a level of no more than 20% of the diet.
Dietary Ascorbic Acid Requirements of Fingerlings of Genetically Improved Rohu (Labeo rohita Ham)
Authors: Sahoo Minakshi , Mukhopadhyay P.K.
Published: February 2021

Indian major carp, including Labeo rohita, are incapable of biosynthesizing ascorbic acid due to the absence of the enzyme L-gulono-γ-lactone oxidase. To assess their ascorbic acid require- ments, improved rohu fingerlings (2.33±0.18 g) were fed one of six semi-purified formulated diets containing 0, 20, 40, 60, 80, or 100 mg ascorbyl-2-polyphosphate (APP) per kg feed for 60 days in water of 28-30°C. Fish fed diets deficient in ascorbic acid had a significantly lower weight gain, poor feed conversion (FCR) and protein efficiency (PER) ratios, lower survival, and behavioral abnormalities such as lethargic movements and poor feed intake. The best FCR and PER were recorded in the 60 mg APP diet. Ascorbic acid in the kidney dropped from 36.62 to 5.09 mg/kg by the end of the experiment. Weight gain analysis by regression indicated that the dietary ascor- bic acid requirement for maximum growth and survival of rohu fingerlings can be achieved with 53.5 mg APP incorporated into 1 kg diet.
Population Growth of the Freshwater Cladoceran, Diaphanosoma excisum, Fed Different Densities of the Alga, Scenedesmus acuminatus
Authors: Ovie Solomon I. , Ovie Stella O.
Published: February 2021

The freshwater cladoceran, Diaphanosoma excisum Sars 1885, was fed the micro-alga Scenedesmus acuminatus, at one of six densities (0.5, 1.0, 1.5, 2.0, 3.0, or 4.0 x 106 cells/ml) in 40-l glass aquaria. The D. excisum density increased as the Scenedesmus density increased to 1.5 x 106 cells/ml, in which it peaked at 7345 individuals per liter. Population growth was inhibit- ed at higher algae densities. The percent of egg-bearing females and the number of eggs per egg-bearing female followed a similar pattern. Production of approximately 7000 individuals per liter was encouraging from a mass production point of view and indicates that S. acuminatus is suitable for use as a live starter feed for D. excisum which, in turn, is a live feed for larvae of induced-breeding in fish hatcheries.
Determining Variability, Confidence, and Statistical Power in Aquaculture Experiments
Authors: Araujo Pedro
Published: February 2021

This article deals with the lack of appreciation among marine biologists of basic statistics in aqua- culture experiments. Topics include calculation of sources of variation, the importance of true replication rather than pseudo-replication to test for treatment effects, estimation and visualization of the confidence of an experimental design used in feeding trials, and calculation of its statisti- cal power. An arbitrary example is used to illustrate how the described theory can be applied in practice. The approach demonstrates that nutritional experiments with a reduced number of tanks can be a valid strategy as long as certain experimental considerations are taken into account. In addition, it shows that information on the relative sizes of ‘between’ and ‘within’ sources of vari- ation can be used to design more efficient experiments by minimizing the effects of the stronger sources of variance. The approaches used in this article are applicable to large and small-scale experiments.
Characterization of Vibrio alginolyticus Isolates from Diseased Cultured Gilthead Sea Bream, Sparus aurata
Authors: Akayli T. , Timur G. , Aydemir B. , Kiziler A.R. , Coskun O. , Albayrak G. , Arican E.
Published: February 2021

Biochemical, pathogenical, antigenical, and molecular characteristics of Vibrio alginolyticus iso- lates from diseased cultured gilthead sea bream juveniles (4 and 20 g) were determined by lab- oratory challenge experiments. Intraperitonal challenge resulted in development of the disease but immersion did not. Electrophoresis of outer membrane protein (OMP) and lipopolysaccha- rides (LPS) was performed using sodium dodecyl sulphate poly-acrylamide gel electrophoresis (SDS-PAGE). Molecular typing of Vibrio isolates was conducted using random amplification of polymorphic DNA (RAPD). According to SDS-PAGE of surface antigens of the isolates, profiles of both OMP and LPS were heterogeneous. According to RAPD, isolated bacteria varied genet- ically. The findings reveal differences among V. alginolyticus isolates from diseased cultured gilt- head sea bream in Turkey.
Antibacterial Activity of Marine Sponge Extracts against Fish Pathogenic Bacteria
Authors: Annie Selva Sonia G. , Lipton A.P. , Paul Raj R.
Published: February 2021

Secondary metabolites of the marine sponges Acanthella elongata, Axinella donnani, Callyspongia diffusa, Callyspongia subarmigera, and Echinodictyum gorgonoides were collect- ed from fishing nets and their in vitro antibacterial properties against eight virulent marine fish pathogens were studied at incubation temperatures of 20°C and 30°C. Crude methanol extracts of the tested sponges showed species-specific antibacterial activity. The most active species was A. elongata which inhibited 100% and 87.5% of the tested bacterial isolates at 20°C and 30°C, respectively. Callyspongia subarmigera was the least active as it inhibited only 62.5% and 50% of the tested bacteria at those temperatures. Results suggest that fractionation and purifi- cation of the crude methanol extract of A. elongata has potential in the development of novel antibiotic substances for managing common bacterial diseases in aquaculture.
Partial Replacement of Fishmeal by Defatted Soybean Meal in Diets for Black Sea Turbot (Psetta maeotica): Growth and Nutrient Utilization in Winter
Authors: Ergun Sabahattin , Yigit Murat , Türker Ali , Harmantepe Burcu
Published: February 2021

The objective of the present study was to evaluate replacement of white fishmeal by soybean meal in practical diets for Black Sea turbot (Psetta maeotica) at levels of 0, 10%, and 20%. The diets were fed to triplicate groups of juvenile Black Sea turbot (initial body weight 18 g) for 60 days. At the end of the trial, there were no differences in growth performance, feed utilization, and nitrogen retention between the control group fed 100% fishmeal and the experimental groups fed 10% or 20% soybean meal. In conclusion, 20% inclusion of soybean meal can allow reduction of white fishmeal by up to 14%, leading to savings on fishmeal protein.
Genetic Diversity and Population Structure of the Peanut Worm (Sipunculus nudus) in Southern China as Inferred from Mitochondrial 16S rRNA Sequences
Authors: Xiadong Du , Zian Chen , Yuewen Deng , Qingheng Wang , Ronglian Huang
Published: February 2021

Genetic diversity and population structure of the peanut worm (Sipunculus nudus) were investi- gated by using 536 base-pair fragments of the mitochondrial 16S ribosomal gene. Populations were collected from three locations along the southern coast of China - Beihai, Sanya, and Xiamen. Amplified polymerase chain reaction products were sequenced in both directions and data were analyzed using ClustalX, Arlequin, and MEGA. A total of 69 polymorphic sites and 21 distinct haplotypes were revealed. The mean haplotype and nucleotide diversity of the three pop- ulations were 0.814% and 0.37%, respectively. The Beihai population had the greatest haplo- type and nucleotide diversity, followed by the Xiamen and Sanya populations. Analysis of mole- cular variance (AMOVA) showed significant genetic differentiation among the three populations (Fst = 0.0619, p<0.05) and distinct population structures among the three sites.
Digestive Enzymes and Hormones in Gilthead Seabream Larvae (Sparus aurata) Fed Artemia Nauplii Enriched with Free Histidine
Authors: Naz Mehmet , Turkmen Mustafa
Published: February 2021

The digestive enzymes and hormones of gilthead seabream (Sparus aurata) larvae fed live prey (Artemia nauplii) enriched with free histidine were investigated for 16 days (from day 24 to day 40 after hatching). Larvae were sampled at 4-day intervals. The control group had significantly lower growth than the enriched group (p<0.05). Trypsin activity was higher in the control (p<0.05). Bombesin activity significantly differed between treatments, periods, and period x treatment interac- tions and the cholecystokinin level was significantly higher in the enriched groups (p<0.05). Results indicate that Artemia nauplii can successfully be enriched with free histidine, bombesin and chole- cystokinin activity can be stimulated by free histidine, and mechanisms controlling the adaptation of trypsin activity to the amount of dietary protein were not activated within the 40-day study period.
Effects of dietary protein and lipid levels on growth and body composition of silver dollar (Metynnis schreitmuellerei) fry
Authors: Singh R.K. , Vartak V.R. , Balange A.K.
Published: February 2021

The aims of this study were to determine the effects of different levels of protein and lipid on the growth and body composition of fry of the silver dollar, Metynnis schreitmuelleri (Ahl). The fry were first fed diets containing 25, 35, 45, or 55% protein to determine the optimum protein level. The best growth, body composition, protein efficiency ratio, and food conversion ratio were obtained with the 35% protein diet. The fry were next fed diets containing 35% protein and 0, 3, 6, 9, or 12% lipid. The best growth, body composition, protein efficiency ratio, and food conver- sion ratio occurred with the diet containing 35% protein and 6% lipid.
Effects of dietary mannan oligosaccharides (MOS) on growth, body composition, and intestine and liver histology of the hybrid tilapia (Oreochromis niloticus x 0. aureus)
Authors: Ayce Genc M. , Yilmaz Erdal , Genc Ercument , Genc Ercument , Aktas Mevlut
Published: February 2021

This is the first study on the effects of dietary mannan oligosaccharides (MOS) on growth, body composition, and intestine and liver histology of hybrid tilapia (Oreochromis niloticus x O. aureus). Experimental diets were prepared from commercial trout diet, supplemented with MOS at levels of 0, 1.5, 3.0, or 4.5 g MOS/kg feed and randomly assigned to triplicate groups. At the end of the trial, there were no significant differences between treatment groups (p>0.05) in growth parameters (live weight gain, specific growth rate, feed conversion ratio, protein efficien- cy ratio) or body indices (hepatosomatic and viscerosomatic). Dry matter and protein contents increased with increasing rates of dietary MOS (p<0.05) while the mean villi length of fish fed the diet containing 1.5‰ MOS was significantly longer (p<0.05) than that of the fish fed 4.5‰ dietary MOS. The different levels of dietary MOS had no detrimental effects on liver tissue or general fish health.
Heterosis in the Growth Rate of Hungarian-Israeli Common Carp Crossbreeds and Evaluation of their Sensitivity to Koi Herpes Virus (KHV) Disease
Authors: Zak Tatyana , Perelberg Ayana , Magen Igai , Milstein Ana , Joseph Dan
Published: February 2021

Koi herpes virus (KHV) disease first occurred in Israel in spring 1998. In search of genetic solu- tions to the disease, two strains of domesticated common carp (Szarvas-22 and Dinnyes) were imported from Hungary in 2002 to test their genetic contribution to KHV resistance and hetero- sis in growth parameters when crossed with a local strain (Dor-70). During 2004, six genetically different groups were reared, including the three above-mentioned strains and three crossbreeds (Szarvas-22 x Dor-70, Dinnyes x Dor-70, and Nasic x Dor-70). Fish were vaccinated by injection of an inoculum containing attenuated virus, individually marked, stocked in communal earthen ponds, and cultured to market size. Data on resistance to the disease and growth rates were col- lected. The two Hungarian strains and their crossbreeds had no advantage in specific resistance to KHV but contributed to heterosis when crossed with Dor-70. This was expressed by an increase of more than 10% and 20% in growth rate, compared to the commercial Israeli cross- breed (Nasic x Dor-70).
Evaluation of Anchovy Meal and Soybean Meal as Dietary Protein Sources for the Black Sea Turbot, Psetta maxima
Authors: Hasimoglu Atila , Erteken Adnan , Kino Sohei , Nakagawa Heisuke
Published: February 2021

Soybean meal and locally-produced anchovy (Engraulis encrasicolus) fishmeal were evaluated as protein sources in the intensive culture of Black Sea turbot, Psetta maxima, by comparing them with imported Alaskan fishmeal. Three diets were prepared. One contained imported fish- meal and the second anchovy fishmeal. In the third diet, part of the anchovy fishmeal was replaced by soybean meal. The dietary protein levels were adjusted to approximately 50%. Juveniles (avg wt 8.2 g) were reared for 61 days in triplicate tanks. Growth and feed efficiency in fish fed the anchovy fishmeal diet were inferior to those of fish fed the imported fishmeal diet, indicating the need to improve the quality of the anchovy fishmeal. Partial replacement of the anchovy fishmeal by soybean meal resulted in worse growth performance. The low growth rates obtained with the anchovy fishmeal diet and the anchovy plus soybean diet were accompanied by low lipid and glycogen accumulation. Fatty acid compositions of the muscle and liver were not influenced by the dietary protein source. The inferior results with the soybean meal diet might have been due to effects of anti-nutrients on the digestive system.
Fishes of the Eastern Mediterranean
Authors: Golani Daniel , Ozturk Bayram , Basusta Nuri
Published: February 2021

Few seas have evidenced an environmental impact throughout human history to the degree that the eastern Mediterranean has. In the last century alone, the Levant Basin has seen the opening of the Suez Canal, leading to a massive Red Sea biological invasion, and construction of the Aswan Dam on the Nile River, leading to an abrupt cessation of its annual floodwaters. These man-made activi- ties have had a serious impact on the eastern Mediterranean causing the collapse of some fisheries, the creation of others, and large- scale alterations in the ecosystem. This book deals with fish species living in the Levant Basin and includes all currently-known indige- nous and immigrant species.
The Fatty Acid Profile of the Marine Cephalopod Loligo vulgaris
Authors: Salman Yesim , Salman Alp , Ozkizilcik Sureyya
Published: February 2021

Squids and their by-products are widely used as pre-spawning feeds in marine fish hatcheries. Therefore, we studied the fatty acid composition of mantle tissue, arms, fins, and gonads of the marine cephalopod, Loligo vulgaris, from a broodstock nutrition point of view. Docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids represented nearly half (>45%) of the total fatty acids, with DHA the most abundant fatty acid in all investigated tissues. The fatty acid profile of the gonads differed significantly from those of the mantle, arms, and fins; EPA was present in a sig- nificantly higher proportion (20%), perhaps indicating its important role in reproduction. Results indicate that Loligo vulgaris and its by-products can be an important nutritional component of broodstock feeds, serving as a major source of DHA and EPA.
Effects of n-3 PUFA Levels in Live Foods on Albinism, Growth, Survival, and Salinity Tolerance of Flounder (Paralichthys olivaceus) Larvae in Large-Scale Artificial Rearing
Authors: Wel Wang , Xiangyang Zou , Feng Yao , Liqiao Chen
Published: February 2021

The effects of feeding enriched rotifers and Artemia nauplii on albinism in flounder (Paralichthys olivaceus) larvae raised in a large-scale artificial system were investigated. Larvae were first fed an S-type rotifer (Brachionus angularis) enriched with Nannochloropsis oculata for 11-12 days, which raised the n-3 polyunsaturated fatty acids (PUFA) content in the rotifer from 5.36% to 17.63% of the total fatty acids. Next, the larvae were fed one of three strains of Artemia enriched with microcapsule (50DE), vitamin A (9000 IU/l), and vitamin D (2000 IU/l) for 35 days, which raised the n-3 PUFA contents in the Artemia to 38.62%, 36.53%, and 33.86% of the total fatty acids, respectively. Among the larvae fed the enriched feeds, no more than 3‰ were albino, much fewer than in the control groups fed non-enriched foods (p<0.01). In addition, n-3 PUFA contents in the muscles, growth and survival rates, and salinity tolerance were greater in founder fed the enriched foods. Artemia nauplii from Qixiangcuo (Tibet, China), enriched to 38.62% of total fatty acids, was superior in preventing albinism than the strains from Pikou or Yingkou (Liaoning, China).
Reproductive Performance of Wild and Hatchery-Reared Black Sea Salmon
Authors: Sahin Temel , Akbulut Bilal , Cakmak Eyup , Cavdar Yahya
Published: February 2021

Spawning period, total fecundity, egg size, and fertilization and hatching rates of wild and hatch- ery-reared Black Sea salmon (Salmo trutta labrax Pallas, 1811) were investigated. Wild brood- stock consisted of 15 females (4-5 years old) with a mean weight of 1773.2±1014.4 g. Hatchery- reared broodstock consisted of 28 females (3 years old) with a mean weight of 869.5±319.6 g. The spawning period lasted from mid-November to the beginning of January. Mean total fecun- dity was 3524.6±2106.9 and 1931.3±915 eggs/female for wild and hatchery-reared broodstock, respectively, and mean egg diameters were 5.2±0.20 and 5.0±0.24 mm. Fertilization and hatch- ing rates were 98.4±1.71% and 88.1±8.78% for wild broodstock and 97.9±1.84% and 83.1±15.77% for hatchery-reared. The reproductive parameters of wild and hatchery-reared Black Sea salmon in northeastern Turkey were similar to those of other salmonid species.
Spawning Induction in the Carp: Past Experience and Future Prospects - A Review
Authors: Levavi-Sivan Berta , Kulikovsky Z. , Aizen Joseph , Biton Iakov , Drori S. , Bogomoinaya A. , Yaron Zvi
Published: February 2021

Most fish in aquaculture either fail to breed in captivity or their spawning occurs sporadically and late in the season. This is mainly due to the lack of natural cues in captivity, which leads to dysfunction of the endocrine axis regulating oocyte maturation and ovulation. Hypophysation as a remedy for this situation in fish has been employed in aquaculture since the 1930s and is still widely practiced. However, using crude pituitary homogenates in local hatcheries has frequently ended in failures that were attributed to the incon- sistent potency of the injected material and the unknown ovarian stage of the recipient fish. Since the mid 1980s, hypophysation has improved through the introduction of a standardized dry carp pituitary extract in which the luteinizing hormone (LH) content and activity have been calibrated (cal- ibrated carp pituitary extract = CCPE). Induction of spawning, however, is successful mainly in female cohorts in which 65% or more of the oocytes in an ovarian biopsy have migrating germinal vesicles. Further, due to decreasing quantities of industry-processed common carp and the expan- sion of ornamental carp production (koi and goldfish), the growing demand for CCPE could not be met, and an alternative had to be found. A hypo- thalamic approach, introduced into Israeli aquaculture in 1993 (called Dagin), combines a superactive analog of sGnRH (10 μg/kg), with the water-soluble dopamine (D2) receptor antagonist, metoclopramide (20 mg/kg). The progress of oocyte maturation in ovarian biopsies has been studied in parallel with changes in levels of LH, estradiol, and the matura- tion-inducing steroid (MIS; 17α, 20β, dihydroxy-4-pregnene-3-one). The hormone profile indicated that the gradual increases in LH and MIS follow- ing a single administration of Dagin were similar to those in fish treated with priming and resolving doses of CCPE. This would explain why Dagin is effective even when only a single injection is given, saving labor and reduc- ing handling stress. CCPE and Dagin were tested in parallel on common carp in a commercial hatchery. The spawning ratio and embryo viability were similar, although the latency between injection and ovulation was con- siderably longer and more variable in Dagin-treated than in CCPE-treated carp. It is recommended to use CCPE at the beginning and end of the spawning season when the LH content in the pituitary is low, and Dagin in mid-season and in field spawning. Future prospects raise the possibility that by employing molecular tools, a recombinant carp LH will be produced that will have the regular and expected potency of the hypophyseal approach without the risk of spreading pathogens from donor fish to broodstock. Work along this line is currently in progress.
Effect of Photoperiod on Growth of Trout (Oncorhynchus mykiss) in Cold Ambient Sea Water
Authors: Türker Ali
Published: February 2021

The effects of four photoperiod regimes on growth performance of the rain- bow trout (Oncorhynchus mykiss W.) in cold ambient seawater conditions were compared in indoor seawater tanks (salinity 18 g/l; 6-8°C) in Janu- ary-February. The photoperiods were the natural photoperiod (10 h light: 14 h dark), 20 h light:4 h dark, 16 h light:8 h dark, and 0 h light:24 h dark. Fish were fed a diet consisting of 47% protein, 20% fat, 11% ash, and 8.5% moisture. At the end of eight weeks, the relative growth rate and feed intake were significantly higher in fish exposed to 20L/4D than in other photore- gimes. Total protein intake (g), protein retention (%), and N content in fish (%) significantly improved with the increase of light hours, indicating that optimal growth in the study conditions is obtained in extended light regimes (20L/4D or 16L/8D).
Effects of Live Food Organisms and Formulated Diets on Growth, Survival, and Body Protein of Asian Sea Bass Fry (Lates calcarifer, Bloch)
Authors: Vartak Vivek Rohidas , Singh Kumar
Published: February 2021

The effects of the live feeds, Artemia, Moina, and Tubifex, and a formulated diet on the survival, growth, and body composition of fry (0.05±0.001 g) of the Asian sea bass, Lates calcarifer (also called barramundi), were evaluat- ed. The formulated diet was supplemented with dry Bombay duck fishmeal (10%) as an attractant. The experiment was conducted for 30 days in 40-l glass aquaria containing 30 l fresh water. The fry fed Artemia had the best survival (70%) and growth rate (6.48±0.10%). Fry fed Moina and formu- lated diet had 60% survival, not significantly different from fry fed Artemia. Survival was poor (30%) in fry fed Tubifex. Body protein and lipid contents differed significantly among treatments. The present study suggests that Artemia nauplii is the better feed for Asian sea bass fry but formulated diet can be used as a substitute since growth and survival were similar.
Embryonic Development of Barbel (Barbus barbus)
Authors: Lugowska Katarzyna
Published: February 2021

Barbel (Barbus barbus L.) is rarely bred and reared in hatcheries, and data on the early development of this species are scarce. Thus, the aim of the study was to describe its embryonic development in detail. Eggs and sperm were obtained from artificially stimulated spawning. Fertilized eggs were incubated in ten 2000-ml aquaria filled with aerated dechlorinated tap water and maintained at a constant 18°C, the optimal temperature for embryonic development of barbel. The eggs swelled to a maximum of 18% during the first hour after fertilization. There were eight distinct stages of embryonic development: two blastomeres, eight blastomeres, small-celled blastula, embryo body formation, body segmentation, formation of brain and eye germs, change of yolk sac shape, and first movement of the embryo. Sur- vival during development was over 81% and during hatching 74%. Of the newly hatched larvae, 88% were normal, 7% were dead, and only 5% had morphological abnormalities, the most common of which were yolk sac mal- formations, spinal cord curvatures, and heart edema.
Marine Secondary Metabolites (MSM) from Macro Algae Enhance Bacterial Clearance in Hemolymph of Penaeus monodon
Authors: Lipton A.P. , Pramitha V.S.
Published: February 2021

Marine secondary metabolites (MSM) from macro algae were incorporated into four experimental feeds for juvenile shrimp (Penaeus monodon) as follows: 1.0% Hypnea musciformis extract (diet 1); 0.1% H. musciformis ex- tract (diet 2); 1.0% H. musciformis extract with 500 mg Ulva fasciata extract and 50 mg of the antibiotic levamisole (diet 3); 1.0% H. musciformis with 500 mg U. fasciata per kg body weight (diet 4). Diet 3 enhanced bacterial clearance to 99.69% in the hemolymph of shrimp challenged with Vibrio alginolyticus and Vibrio fischeri, significantly higher than clearance rates in all other treatments and the unmedicated control. Results suggest that feed containing MSM is a good alternative to application of antibiotics in control- ling bacterial diseases in shrimp.
In vitro Antibacterial Activity of Herbal Medicines and Combinations of Herbal Medicines and Antibiotics against Edwardsiella tarda
Authors: Bai D.Q. , RLi R. , Xing K.Z. , Guo Y.J. , Chen C.X. , Qiao X.T. , Mao H.T. , Zhu G.X.
Published: February 2021

The antibacterial activity of five medicinal herbs, alone and together with other herbs or one of six antibiotics, against Edwardsiella tarda was determined by World Health Organization-International Collaborative Study (WHO-ICS) agar dilution protocol. Minimal inhibitory concentrations (MIC) of the herbs were significantly lower (≤4 mg/ml) in treatments using the combinations Rhizoma coptidis+Radix scutellariae, Galla chinensis+Radix et Rhizoma rhei, Galla chinensis+Radix scutellariae, and Radix et Rhizoma rhei+Radix scutellariae than in treatments using Rhizoma coptidis, Radix et Rhizoma rhei, or Flos lonicerae (≥32 mg/ml). Almost all the combination treatments were more effective than treatment by a single herb. Combinations containing herbal medicines and regular antibiotics resulted in varying results: antibacterial effects increased with some combinations and decreased with others. Galla chinensis is suitable for use with most antibiotics, while streptomycin sulfate is suitable for use with many herbal medicines.
Effects of Starter Diets on Pancreatic Enzyme Activity in Juvenile Sterlet (Acipenser ruthenus)
Authors: Napora-Rutkowski Lukasz , Kamaszewsk Maciej , Bielawski Wieslaw , Ostaszewska Teresa , Wegner Arieta
Published: February 2021

Nine-day-old sterlet (Acipenser ruthenus) larvae were reared for 21 days on one of three commercial diets with different protein and fat contents: Bio Kyowa, Aglo Norse, or Perla Larva Proactive. At the end of the experiment, the sterlet juveniles were sampled for histological analysis of the pancreas and evaluation of lipase, trypsin, and amylase activity. Fish fed the Bio Kyowa and Aglo Norse diets were the largest. Survival was highest in the Aglo Norse group. There were no differences between groups in histologi- cal analysis of the pancreas, and no histological anomalies. The highest lipase activity was observed in fish fed the diet with the highest lipid content (21%) - the Aglo Norse diet. Trypsin activity was higher in fish fed Bio Kyowa with a protein content of 55% than in fish fed Aglo Norse with a pro- tein content of 59%.
DNA Barcoding of Israeli Indigenous and Introduced Cichlids
Authors: Shirak Andrey , Cohen-Zinder Miri , Barroso Renata M. , Seroussi Eyal , Ron Micha , Hulata Gideon
Published: February 2021

The objectives of this study were barcoding and taxonomic analysis of the five tilapiine species (Oreochromis aureus, O. niloticus, O. mossam- bicus, Sarotherodon galilaeus, and Tilapia zillii), two tilapia hybrid strains (Florida red tilapia and Philippine red tilapia), and two endemic wild cichlids (Tristramella simonis and Astatotilapia flaviijosephi) available in Israel, as well as O. urolepis hornorum. Cytochrome oxidase subunit I (COI) 619 bp sequence traces of 104 individuals were assembled, aligned, and compared (GenBank project GI 209553463). The DNA sequences of two hybrid strains were identical to those of O. hornorum and O. aureus. Absence of intra-specific variability was detected in the commercially used species, O. aureus, S. galilaeus, O. mossambicus, and O. urolepis horno- rum. Two DNA sequence variants were detected in O. niloticus originating from Ghana and Egypt. In contrast, 2-3 variants were detected in the DNA of each of the non-commercial species. Amino-acid sequences were identical in all “true tilapias” and different from the sequences in the endemic cichlids. As a whole, the protein phylogenetic tree fitted the expected conventional taxonomy as opposed to the respective DNA-based tree. Sequences FJ348047-FJ348150 were submitted to GenBank via the BOLD database (identical to FISH001-08 - FISH104-08 in this database).
Current Status of Viral Diseases in Asian Shrimp Aquaculture
Authors: Flegel T.W.
Published: February 2021

The giant or black tiger shrimp, Penaeus monodon, was formerly the dom- inant cultured shrimp species in Asia. Since approximately 2002, it has been essentially replaced by the domesticated American whiteleg shrimp P. vannamei. The change in dominant species has affected disease concerns. For both species, white spot syndrome virus (WSSV) and yellow head virus (YHV) are the most lethal. For P. monodon, the next most important dis- eases are hepatopancreatic parvovirus (HPV) and monodon baculovirus (MBV). For P. vannamei, they are taura syndrome virus (TSV) and infec- tious hypodermal and hematopoietic necrosis virus (IHHNV). TSV was introduced to Asia in 1998 by careless importation of shrimp stocks for aquaculture but has not been reported to cause problems with local crus- tacean species. IHHNV, which is endemic in Asia, is harmless to P. mon- odon but poses a constant threat to IHHNV-free stocks of P. vannamei if they are hatched and reared in Asia under non-biosecure conditions. An emerging disease for P. monodon is monodon slow growth syndrome (MSGS), a component of which seems to be Laem-Singh virus (LSNV). Infectious myonecrosis virus (IMNV) is a P. vannamei disease, first report- ed from Brazil but now reported in Indonesia where it was probably intro- duced by careless importation of shrimp aquaculture stocks. So far, IMNV has not been reported in other Asian countries. Penaeus vannamei nodavirus (PvNV) is a new pathogen first reported from Belize in 2004 with gross and histological signs that are indistinguishable from those of IMNV. The disease has not yet affected Asian culture. A more recent disease of P. vannamei in Asia is abdominal segment deformity disease (ASDD), possi- bly caused by a yet unknown local virus.
Current Knowledge on Viral Nervous Necrosis (VNN) and its Causative Betanodaviruses
Authors: Nakai T. , Sugaya T. , Nishioka T. , Mushiake K. , Yamashita H.
Published: February 2021

Viral nervous necrosis (VNN) or viral encephalopathy and retinopathy (VER) caused by betanodaviruses (Nodaviridae) has seriously damaged global marine aquaculture since its first appearance in the late 1980s. In the past two decades, more than 100 papers have been published on the dis- ease. Although information is still limited, we now have more knowledge on the taxonomic position and molecular characteristics of betanodaviruses, and on the diagnosis, control, and infection mechanisms of the disease. This paper briefly reviews studies on VNN and betanodaviruses.
Hemorrhagic Disease of Grass Carp: Status of Outbreaks, Diagnosis, Surveillance, and Research
Authors: Jiang Yulin
Published: February 2021

Hemorrhagic disease of grass carp is the most serious infectious disease of grass carp and causes significant losses of fingerlings. The main clinical signs are external and internal hemorrhage. The disease is caused by aquareovirus and has several serotypes. The optimal epidemic temperature of this disease is 25-28°C. The disease can be transmitted by water or par- asite bite. Susceptible hosts are grass and black carp. Other cyprinids are only carriers. Vaccination can control hemorrhagic disease of grass carp. An inactivated vaccine prepared from organs of sick fish is simple and easy to produce with good efficacy. In China, hemorrhagic disease of grass carp was prevalent but has been controlled by wide application of the vaccine. In other Southeast Asian countries, it is a new disease. For surveillance and diagnosis of hemorrhagic disease of grass carp, isolation of the virus using carp kidney (CK) cells and reverse transcriptase polymerase chain reaction (RT-PCR) are the main methods of detection.
Spring Viremia of Carp Virus (SVCV): Global Status of Outbreaks, Diagnosis, Surveillance, and Research
Authors: Goodwin Andrew E.
Published: February 2021

The spring viremia of carp virus (SVCV) is an OIE-listed rhabodovirus his- torically responsible for losses of cultured fish in Europe. Acute disease is associated with high mortality, especially in common carp Cyprinus carpio during their first spring season when water temperatures are 10-15°C. Mortality has been reported in other cyprinids and in the Wels catfish Siluris glanis. The disease is characterized by hemorrhages on the skin and bloody mucus in the intestine, clinical signs shared by other diseases including bacterial infections. In 2002, SVCV was detected on a large koi farm in the USA. The USA isolate was 98% identical to isolates associated with koi and goldfish imported from China, but distantly related to European strains. In spring 2002, a major SVCV kill of common carp occurred in Cedar Lake, Wisconsin. This isolate was also of the Asian type, as were subsequent isolates from wild and cultured fish in several states. In the USA, all infected farmed populations were destroyed and no additional iso- lates have been detected since 2004. One of the most critical aspects of SVCV diagnosis is to differentiate the disease from the koi herpesvirus (KHV). The most obvious difference is that KHV generally occurs in tem- peratures of 20-28°C while SVCV disease occurs below 18oC and com- monly at 10-15°C.
Koi Herpesvirus: Status of Outbreaks, Diagnosis, Surveillance, and Research
Authors: Yuasa Kei , Sano Motohiko
Published: February 2021

Koi herpesvirus (KHV; Cyprinid herpesvirus 3) is a major threat to common carp and koi carp production worldwide. It is listed by the World Organization for Animal Health (OIE), and has been reported in 26 coun- tries. KHV was designated a Specific Disease by Japanese law in 2003. Japan’s National Research Institute of Aquaculture (NRIA) is a reference laboratory for the disease and conducts confirmatory diagnosis. The num- ber of disease occurrences in Japan peaked in 2004, but has been gradu- ally decreasing since then. The disease occurs mostly during spring and autumn when water temperatures are 16-28°C. In general, conventional polymerase chain reaction (PCR) is the most useful method for diagnosing KHV due to its high sensitivity, high specificity, and rapidity. More recently, real time PCR, nested PCR, and loop-mediated isothermal amplification (LAMP) were developed to diagnose the virus. Reverse transcriptase poly- merase chain reaction (RT-PCR) targets mRNA of KHV to detect the repli- cating virus. An enzyme-linked immunosorbent assay (ELISA) detects anti- KHV antibodies in carp serum of surviving infected fish and is expected to be a tool for surveillance of KHV. However, cross reactions with anti- Cyprinid herpesvirus 1 antibodies in the ELISA need to be resolved. A sys- tematic research project on development of diagnostic and prevention tech- nologies for KHV disease was conducted in 2004-2006 by the NRIA in cooperation with Japanese universities and enterprises and SEAFDEC. The fruitful results of the project are included in this review.
Interaction of Spirulina with Different Levels of Vitamin E on Growth, Reproduction, and Coloration in Goldfish (Carassius auratus)
Authors: James Raja , Vasudhevan Iyyadurai , Sampath Kunchitam
Published: February 2021

The interaction between spirulina (30 g/kg diet) and different levels of vita- min E (100, 200, 300, and 600 mg/kg diet) on growth, gonad weight, repro- duction, and coloration were studied in goldfish, Carassius auratus, for 120 days. The mean body weight increased with time in all experimental diets. Growth, gonad weight, and fecundity in fish fed the diet containing spiruli- na+300 mg vitamin E were significantly (p<0.01) enhanced, compared to other diets. Supplementation of vitamin E beyond this level significantly (p<0.01) reduced gonad weight and, subsequently, fecundity. Control fish spawned only once, with fewer eggs per spawn, than other groups, which spawned twice with a greater number of eggs per spawn. Females fed spir- ulina without vitamin E laid 703 eggs in two spawnings compared to 1057 eggs in fish fed with the spirulina+300 mg vitamin E diet. Fish treated with other combinations laid fewer eggs. While all combinations of spirulina and vitamin E significantly enhanced coloration, the combination of spiruli- na+300 mg vitamin E was the most influential.
Induction of All-triploid Japanese Flounder (Paralichthys olivaceus) by Cold Shock
Authors: Xu Tian-jun , Chen Song-Lin
Published: February 2021

Cold shock is a useful method of inducing triploidy in some fish species. In this paper, triploidy in Japanese flounder (Paralichthys olivaceus) was induced by applying cold shocks of 3°C, three or four minutes after fertilization, for 15, 25, 35, 45, 55, or 65 min. Ploidy of fry was analyzed using a ploidy analyzer. Survival was lower in treatments shocked at four minutes than in treatments shocked at three minutes after fertilization, and decreased as the duration of the cold shock increased. The abnormality rate increased with the shock duration. The best results were achieved in the treatment shocked three minutes after fertilization for 25 min, resulting in 100% triploidy with the highest survival rate (93.27%) and one of the lowest abnormality rates (15.87%). This study shows that cold shock is a highly effective method for inducing triploidy in the Japanese flounder.
Detection of KHV in Freshwater Mussels and Crustaceans from Ponds with KHV History in Common Carp (Cyprinus carpio)
Authors: Kielpinski Maciej , Kempter Jolanta , Panicz Remigiusz , Sadowski Jacek , Schütze Heike , Ohlemeyer Stefanie , Bergmann Sven M.
Published: February 2021

Characterization of asymptomatic KHV carriers may help understand virus transmission and storage. Such information allows farmers to minimize KHV on farms where this virus is present, also in common carp (Cyprinus carpio) monocultures. As asymptomatic KHV carriers, freshwater mollusks from the Unionidae family (swan mussels, Anodonta cygnea) and crustaceans from the Gammaridae family (scud, Gammarus pulex) were studied because of their unique method of feeding by accumulating bacterial and viral particles. The KHV genome was detected by nested PCR and confirmed by PCR recognizing the KHV glycoprotein gene in ORF 56 (KHV-U). Both PCR and nested PCR, which recognize the KHV thymidine kinase gene, always produced negative results in the swan mussels and scud samples.