bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunostimulatory Effects of a Yeast (Saccharomyces cerevisiae) Cell Wall Feed Supplement on Rohu (Labeo rohita), an Indian Major Carp
Authors: Pal Devonita , Joardar Siddhartha N. , Roy Barun
Published: February 2021

The immunostimulatory role of an orally administered yeast cell wall preparation from Saccharomyces cerevisiae (NutrifermTM) was assessed in the Indian major carp, rohu (Labeo rohita). Fish were fed a diet containing the preparation for 15 days and then returned to the con- trol diet for 20 days. Non-specific immunity was assessed at the end of the experimental feed- ing period (day 0) and on days 10 and 20. In vitro oxidative radical production, phagocytosis of leukocytes, nitrite production, and proliferation of lymphocytes were determined. All four para- meters remained stable in control fish but, in fish fed the supplemented diet, reached a peak on day 10 and remained higher than in the control until day 20, indicating that ingestion of the diet containing the yeast cell wall preparation for 15 days had significant immunostimulatory effects.
Antibacterial Activity of Oxytetracycline Hydrochloride, Environmentally-Protected or Not, after Feed-Pelleting and during Decay-Dispersion in Saline Water
Authors: Laredo B.S. , Ocampo C.L. , Sumano L.H.
Published: February 2021

Bivalent and trivalent cations quelate oxytetracyline (OTC), rendering it microbiologically inac- tive. Yet shrimp diseases are often treated with OTC in pelleted feeds. Attempts have been made to chemically protect the OTC concentration in shrimp feeds against degradation in brack- ish water and due to temperature. The antibacterial activity of two such environmentally-protect- ed OTC preparations (premixes A and B) and one unprotected OTC premix (C) were tested (a) before and after pelleting the OTC premixes with the powdered feed ingredients and (b) during decay-dispersion of the OTC-medicated feed in brackish water. In all three treatments, the OTC concentration dropped by approximately half after pelleting (p<0.001). When pellets were placed in tanks containing water of 23-25°C, pH 7.6-7.8, and marine salt (40 g/l), a second order expo- nential decay of antibacterial activity followed, reaching 50% in 30 min. At 150 min, loss reached 80% in group A, 85% in group B, and 98% in group C, suggesting that only environmentally-pro- tected OTC may, in some cases, reach the minimal therapeutic concentration necessary to treat Vibrio spp. diseases.
Masculinization of African Catfish (Clarias gariepinus) Treated with Gokshura (Tribulus terrestris)
Authors: Turan Funda , Cek Sehriban
Published: February 2021

The present paper describes the effects of Tribulus terrestris, a masculinization agent, on the sex reversal of African catfish, Clarias gariepinus. One-day-old hatchlings were immersed in water containing an extract of T. terrestris at a rate of 0, 3, 6, or 9 g/30 l water for 30 days. The 9 g treatment resulted in 80.42% male populations. Morphological and histological examinations of the gonads in all groups revealed no intersex fish. Histological examination of fish treated with T. terrestris revealed no damage to the testes or ovaries. Despite differences in sex ratio, growth rate, ovaries, and testes, fish treated with T. terrestris were histologically similar to fish from the control groups. Survival ranged from 72% in the 3 g group to 80% in the 9 g during treatment and did not significantly differ from the control (p>0.05). The best growth was obtained in the 9 g treatment.
Effects of a Probiotic Bacterium, Lactobacillus acidophilus, on the Growth and Survival of Pearl Oyster (Pinctada margaritifera) Spat
Authors: Subhash S.K. , Lipton A.P.
Published: February 2021

The present study investigated the effect of a probiotic bacterium, Lactobacillus acidophilus, on the growth and survival of pearl oyster, Pinctada margaritifera, spat. The probiotic bacteria was fed together with a microalgal feed at 1:1 or 2:1 while control groups received no probiotic sup- plementation. The probiotic groups had significantly higher survival (78.7±8.1 and 85.7±2.9%, respectively) than the control groups (60.7±1.2%). Weight and length also increased significant- ly. The weight gains in the probiotic groups were 349.8±0.44 mg (1:1 level) and 396.8±0.49 mg (2:1 level) mg, compared to 300.9±0.51 mg in the control. The increases in dorso-ventral mea- surement were 20.08 mm (1:1 level) and 21.04 mm (2:1 level) in the probiotic groups, compared to 14.22 mm in the control.
Effects of 2,2-Dichlorovinyl Dimethyl Phosphate (DDVP) on Hsp70 Gene Expression in Rainbow Trout
Authors: Erdogan Orhan , Atamanalp Muhammed , Sisman Turgay , Aksakal Ecrument , Alak Gonca
Published: February 2021

2,2-Dichlorovinyl dimethyl phosphate (DDVP) is used to control insects on crops, household, and stored products, and treat external parasitic infections in farmed fish, livestock, and domestic animals. Ectoparasitic copepods can cause severe skin damage in fish that may lead to death through osmoregulatory failure or infection by opportunistic pathogens. There is considerable uncertainty about whether or not DDVP is implicated in cancer, and the wider environmental con- sequences of its use. In general, and specifically in developing countries and fish farming, less hazardous alternatives are available. The present experiment studied the effects of DDVP at a daily dose of 1.6 mg/l for 21 days on the expression of the heat shock protein (Hsp) 70 gene in rainbow trout (Oncorhynchus mykiss). Hsp70 from control and DDVP-exposed fish was ampli- fied for 20-40 PCR cycling. After the fortieth PCR cycle, the Hsp70 level in mRNA was very low in the control fish and very high in the DDVP-exposed fish, with a statistical difference of p<0.01.
Use of PCR-RFLP Analysis of mtDNA Cytochrome-b Gene to Determine Genetic Differences in Capoeta spp.
Authors: Aksakal Ecrument , Erdogan Orhan
Published: February 2021

Genetic differences between Capoeta capoeta capoeta, Capoeta capoeta umbla, and Capoeta tinca were determined using PCR-RFLP of mtDNA cytochrome-b (Cyt-b) by amplifying approxi- mately 400-500 bp of this region from each of the three subspecies. The restriction enzymes SpeI and HinfI did not indicate genetic differences but AluI and HpaII did. Thus, PCR-RFLP of the mtDNA was used to distinguish between closely related subspecies without having to ana- lyze the entire DNA sequence of specimens. Use of this technique demonstrated that the Cyt-b regions of the three subspecies have different base sequences. The similarity between C. c. capoeta and C. c. umbla is 71.4% while C. tinca is more distant (50% for C. c. umbla and 33.3% for C. c. capoeta). The Cyt-b similarity is consistent with morphological and taxonomical similar- ities. PCR-RFLP can serve as a tool for genetically identifying subspecies of fish in nature and in aquaculture.
Effects of Replacement of Fishmeal with Hazelnut Meal on Growth Performance, Body Composition, and Nutrient Digestibility Coefficients in Rainbow Trout, Oncorhynchus mykiss
Authors: Sevgili Huseyin , Emre Yilmaz , Kanyilmaz Mahir , Uysal Ramazan
Published: February 2021

Hazelnut meal was evaluated as an alternative protein source to fishmeal in diets for rainbow trout, Oncorhynchus mykiss (initial wt 57.5±0.1 g). Hazelnut meal was incorporated in the diet at levels of 0% (control), 7.5%, 15%, 22.5%, and 30%. Diets were tested in triplicate for ten weeks. Higher levels of hazelnut meal produced better growth performance, that was sig- nificantly higher in fish fed 30% hazelnut meal than in the control (p<0.05). Feed utilization and protein efficiency ratios followed a similar trend while the level of hazelnut meal did not significantly affect whole body composi- tion. Apparent digestibility of dry matter and energy of fish fed hazelnut meal at all levels was significantly lower than in fish fed the control (p<0.05). Crude and digestible protein, as well as energy retention, were significant- ly correlated with hazelnut meal level. Nevertheless, energy retention declined in fish fed 30% hazelnut meal. Based on growth performance and nutrient retention, the optimal level of hazelnut meal in diets for rainbow trout may be around 30%.
Improved Induced-Spawning Protocol for the Spotted Rose Snapper (Lutjanus guttatus)
Authors: Ibarra-Castro L. , Alvarez-Lajonchere L.
Published: February 2021

An improved protocol for hormonal induction of spawning in spotted rose snapper (Lutjanus guttatus) resulted in increased spawning efficiency in newly-caught wild breeders and wild-caught adults maintained in captivity for more than a year. A controlled-release delivery system (implant) based on an ethylene-vinyl acetate copolymer (EVAc) matrix was loaded with gonadotropin-releasing hormone agonist (GnRHa). The required GnRHa dose was established in two stages. The first stage included meta-analysis of our earlier experiments with wild spawners; the second stage included new experiments with wild and captive breeders. A nomograph was devel- oped to calculate the required GnRHa implant dose, taking into account the origin of the female (wild vs. captive), the initial mean oocyte diameter, and body weight. The effective GnRHa dose was greater in wild than captive females and, in both cases, inversely related to mean oocyte diameter. Using this nomograph, over half the wild females with a mean oocyte diam- eter of ≥425 μm and over half the captive females with a mean oocyte diam- eter of ≥350 μm responded to GnRHa implant treatment (producing multi- ple spawning events in captives), with mean total relative fecundity ranging 80-278 x 103 eggs/kg body weight and 51-85% fertilization success. The nomograph can be used to calculate the GnRHa implant dose required to induce spawning in this species under commercial aquaculture conditions.
Protozoan and Metazoan Parasites of Cultured Fish in Turkey and their Applied Treatments
Authors: Kayis Sevki , Ozcelep Tuna , Capkin Erol , Altinok Ilhan
Published: February 2021

This publication summarizes information on parasites of Turkish fishes from 2003 to 2008. The information is presented as parasite-host lists and con- tains 79 species of parasites, distributed among the higher taxa as follows: Protozoa (14 species), Monogenea (12), Digenea (15), Cestodes (8), Crustacae (1), Isopoda (7), Copepoda (4), Nematoda (8), Bivalvia (1), Acanthocephala (5), Hirudinea (1), and Myxosporean (3). Many records of parasites not identified to the species level are also included. The parasite- host lists are organized on a taxonomic basis and provide information for parasite species found on host species, known geographic distributions in Turkey, and published sources for each host and locality record.
Larvae Development Stages of the European Flat Oyster (Ostrea edulis)
Authors: Acarli Sefa , Lok Aynur
Published: February 2021

This paper reports on the larvae development of the flat oyster, Ostrea edulis (Linnaeus, 1758), from veliger to pediveliger stage. Adult oysters were induced to spawn by thermal stimulation and large amounts of veliger larvae were obtained for study. Veliger larvae were cultured in 180-l bins at a den- sity of 3 larvae/ml. Larvae, reared at 20±2°C and fed 8-200 x 103 cells/ml of Isochrysis galbana, reached pediveliger larvae in 17 days. Shell length and width at the beginning of the pediveliger stage were 254 and 233 μm, respec- tively. Survival rate from veliger to viable pediveliger stage was 15.5%.
Herbal Extract Effects on White Spot Syndrome Virus (WSSV) in Shrimp (Penaeus monodon)
Authors: Loan Ly T.T. , Uyen Nguyen H.P. , Phuong Vo H. , Cuong Doan V. , Anh Pham V.N. , Hanh Nguyen N. , Anh Le T.T.
Published: February 2021

Synthetic drugs and chemicals used in aquaculture cause disadvantageous side effects, while medicines made from medicinal herbs are non-toxic, easy to use, and pollution- free. Many medicinal herbs have potent antiviral properties. The extract of Phyllanthus amarus is a lignan composed of the compounds: niranthin, phyllanthin, and hypophyllanthin which have an impact on the white spot syndrome virus (WSSV) in the shrimp, Penaeus monodon. The virucidal activities of the three substances were tested by mixing them with WSSV, followed by injection into healthy shrimp. The quantity of WSSV DNA on the gills of tested shrimp was measured before and seven days after injecting the mixture. The quantity decreased significantly after injection. Anti-virucidal activities were also assessed by observation of the mortality rates of injected shrimp. The lignan compound inactivated the virus when injected in P. monodon at a dose of 100 mg per kilogram body weight. The survival rate of the lignan injected shrimp was 96.67% , compared to the positive control in which it was only 3.33% .
Study on the Pathogenesis of the White Spot Syndrome Virus (WSSV) on Juvenile Penaeus monodon in Vietnam
Authors: Doan Cuong Van , Pham Anh Thi Tuyet , Ngo Tuyen Xuan , Le Phuoc Hong , Nguyen Hao Van
Published: February 2021

The white spot syndrome virus (WSSV) causes disease and mortality in cul- tured and wild Penaeus monodon. In this study, specific pathogen-free P. monodon were injected with WSSV to determine in which primary organs the virus replicates and to analyze viral spread. Shrimps were injected with a low SID50 endpoint (shrimp infectious dose resulting in 50% infected shrimp) of 101.5 or a high SID50 of 104 of the virus. Six shrimps per treat- ment were collected at 0, 3, 6, 9, 12, 15, 18, 21, 24, 30, 36, 42, 48, 54, and 60 h post injection (hpi) for detection of the virus in tissues from 10 organs by immunohistochemistry. In shrimps injected with the low dose, WSSV- infected cells were first detected in the heart and antennal gland 12 hpi, then in the foregut, stomach, and gills at 18 hpi. The integument was infect- ed 24 hpi and the hematopoietic tissue, lymphoid organ, midgut, and con- nective tissues 36 hpi. In shrimps that received the high dose, the heart, antennal gland, stomach, gill, and connective and hematopoietic tissues were WSSV-positive 12-15 hpi while the foregut and cuticular epithelium were positive 18 hpi and the lymphoid organ and midgut were positive 21 hpi. The present study confirmed the replication of WSSV in P. monodon heart, antennal gland, foregut, stomach, gills, cuticular epithelium, hematopoietic tissue, connective tissue, and lymphoid organ.
Viral Infections of Macrobrachium spp.: Global Status of Outbreaks, Diagnosis, Surveillance, and Research
Authors: Hameed A.S. Sahul
Published: February 2021

Macrobrachium rosenbergii, a global and economically important cultured freshwater prawn, is farmed on a large scale in many countries. Compared to penaeid shrimps, M. rosenbergii is a moderately disease-resistant species. However, viruses such as Macrobrachium hepatopancreatic parvo-like virus (MHPV), Macrobrachium muscle virus (MMV), infectious hypodermal and hematopoietic necrosis virus (IHHNV), white spot syn- drome virus (WSSV), Macrobrachium rosenbergii nodavirus (MrNV), and extra small virus-like particle (XSV) have been reported and are responsi- ble for economic losses to freshwater prawn culture. MrNV and XSV, the causes of white tail disease (WTD), have been reported as dangerous viruses to M. rosenbergii, resulting in 100% mortality in postlarvae and juve- niles within five days of infection. Clinical signs of WTD include lethargy and opaqueness of the abdominal muscle. Various aspects of WTD are dis- cussed in this paper, including tissue tropism of the causative viruses, host range, virus structure, vertical transmission, pathogenicity, and the possibil- ity of multiplying MrNV and XSV in a mosquito cell line.
Hemorrhage Disease of Cultured Tra Catfish (Pangasianodon hypophthalmus) in Mekong Delta (Vietnam)
Authors: Ly Loan Thi Thanh , Nguyen Du Ngoc , Vo Phuong Hong , Doan Cuong Van
Published: February 2021

This study investigated hemorrhage disease in cultured tra catfish (Pangasianodon hypophthalmus) from An Giang, Ben Tre, Can Tho, and Vinh Long provinces in the Mekong Delta (Vietnam). The disease is characterized by internal organ necrosis, white (spot) nodules in the liver, kidney, and spleen, and petecchial hemorrhages on the tail, fins, and abdomen. Some fish have exophthalmus (pop eye), a reddish and swollen anus, and yellowish fluid in the peritoneal cavity. Moribund fish lose their appetite and swim at the sur- face. Bacteria isolated from the diseased fish consisted of Aeromonas hydrophila (38.8%), A. sobria (4.1%), A. caviae (2.0%), Edwardsiella ictaluri (4.1%), and a gram positive, anaerobic bacteria, Clostridium sp. (40.8%). Histological analyses showed necrotic cells and intranuclear, randomly- arranged, straight rod cells (1.0-1.5 x 3.0-4.0 μm) concentrated in the ulcers. Challenge test with A. hydrophila induced external signs of hemorrhagic dis- ease. Challenge test with Clostridium sp. confirmed the presence of the bac- teria in infected tissues with development of white nodules similar to those in naturally-infected fish. Fish challenged with E. ictaluri exhibited gas bubbles in the stomach and gut with a foul smell. Reovirus-like particles were seen by transmission electron microscopy. Further study is needed to determine the role of each pathogen alone and together with others in the pathogenesis of hemorrhage disease of tra catfish.
Changes in Copper Content of Allogynogenetic Silver Crucian Carp after Application of Copper Sulfate to Fishponds
Authors: Liu Jinlan , Yang Guang
Published: February 2021

Copper sulfate was applied to freshwater fishponds containing allogyno- genetic silver crucian carp and changes in the copper content in fish tissues were measured. The copper content in blood, gill, amd liver went up quick- ly, but remained high for a relatively short time. Twenty-four hours after application, the copper content in the gill and liver reached their highest lev- els, 4.846 mg/kg and 6.624 mg/kg, respectively. The copper content in the blood reached its maximum of 22.125 mg/l three days after application. The copper content in the kidney also reached its maximum, 17.472 mg/kg, on day 3 but the high copper content prevailed until the end of the 20-day observation. The copper content in the muscle reached its maximum, 1.873 mg/kg, on day 7 and its minimum, 0.6 mg/kg, after two weeks.
Effects of Selenium on the Activity of Antioxidant Enzymes in the Shrimp, Neocaridina heteropoda
Authors: Wang Hong-Wei , Cal Duan-Bo , Xiao Guo-Hua , Zhao Chun-Long , Wang Zi-Hui , Xu Hai-Ming , Guan Yue-Qiang
Published: February 2021

The effects of a selenium-supplemented diet on the antioxidant enzyme activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) in muscles of the shrimp, Neocaridina heteropoda, were investigated. Purified diets with six levels (0, 0.15, 0.30, 0.45, 0.60, and 0.75 μg/g) of supplemental Se were fed to N. heteropoda for three months. CAT and GPX activity was determined after one month and SOD activity was determined every month. The activity of the enzymes was dose dependant; activity of all three enzymes was significantly higher in shrimp fed Se-sup- plemented diets than in those fed the unsupplemented control diet. SOD activity significantly rose and fell during the three months and was higher in the second month than in the first or third. For all three enzymes, antioxi- dant activity reached a maximum when the Se concentration was 0.45 μg/g.
Soybean Meal and Rendered Animal Protein Ingredients Replace Fishmeal in Practical Diets for Sea Bass
Authors: Altan Ozgur , Gamsiz Kutsal , Korkut Ali Yildirim
Published: February 2021

A 180-day feeding trial was carried out in net cages to examine replacement of fishmeal with soybean meal supported by meat/bone meal and blood meal in practical diets for sea bass (Dicentrarchus labrax L. 1758). Triplicate groups of fish (initial body weight 110 g) were fed one of four isonitrogeneus (crude protein 46%) and isolipidic (10%) diets. A commercial sea bass diet containing 64% fishmeal as the sole animal protein served as the control. The other three diets contained 0, 20%, or 35% fishmeal and the reduced fishmeal was replaced by different levels of soybean meal, meat/bone meal, and blood meal. The final body weight of fish fed the diet containing 20% fishmeal, 50% soybean meal, 10% meat/bone meal, and 4% blood meal was significantly higher than that of the other three treatments. Results indicate that fishmeal can be reduced to 20% when soybean meal, meat/bone meal, and blood meal are used together in the diet.
Effects of Selected Levels of Water pH on the Growth and Survival of Swordtail (Xiphophorus helleri) Larvae
Authors: Sapkale P.H. , Singh R.K. , Desai A.S.
Published: February 2021

Larvae of swordtail (Xiphophorus helleri) were exposed to pH levels of 5.5, 6.0, 7.0, 8.0, and 8.5 to study growth and survival under laboratory conditions for 42 days. The larvae were fed formulated dry pellets at 7% of their body weight. The growth and survival rates were highest at pH 8.0 and 8.5, while mortality was complete at pH 5.5. In all treatments, the specific growth rate was higher in the first week and decreased in subsequent weeks. Thus, for swordtail larvae, the pH of the water should be between 8.0 and 8.5.
Effect of Dietary Supplementation of Spirulina on Growth and Phosphatase Activity in Copper-Exposed Carp (Labeo rohita)
Authors: James Raja
Published: February 2021

The impact of spirulina supplementation at 0, 2, 4, 6, or 10% on the alleviation of copper toxicity was studied in the freshwater cultivable carp, Labeo rohita. Evaluation was based on selected food utilization parameters and phosphatase activities. Copper concentrations in the aquatic medium, selected body tissues, and fecal matter were analyzed to determine the mechanism of toxicity reduction. Dietary supplementation of spirulina significantly improved the tested physiological and biochemical parameters and reduced the metal burden in tissues. Reduction of metal toxicity seems to be achieved via elimination of metal through feces. A significant positive correlation (r = 0.714; p<0.01; n = 18) was obtained between supplementation of dietary spirulina and copper defecation. The addition of 4% spirulina was optimum since this dose produced the maximum elimination of copper from the body and better physiological and biochemical parameters. The treatment period (21 days) was not sufficient for complete removal of the copper. Therefore, a longer period of supplementation is recommended.
Identification and Antimicrobial Activity of Combined Extract from Azadirachta indica and Ocimum sanctum
Authors: Harikrishnan Ramasamy , Kim Man-Chul , Kim Ju-Sang , Balasundaram Chellam , Jawahar Sundaram , Heo Moon-Soo
Published: February 2021

The  chemical  constituents  of  decoction  (individual)  and  concoction  (mixed)   of   ethanolic   leaf   extracts   from   Azadirachta   indica   (neem)   and   Ocimum

sanctum   (tulsi)   were   analyzed   by   gas   chromatography-­mass   spectro-­ photometery  (GC-­MS).  Decoctions  of  A.  indica  and  O.  sanctum  had  24  and   33   constituents,   respectively.   Mixed   together,   26   compounds   were   identified.   Four   major   (high   percentage)   compounds   were   identified   in   A.   indica:   n-­hexadecanoic   acid   (14.34%),   phytol   (19.96%),   9,12,15-­octa-­ decatrienoic   acid,   (Z,Z,Z)-­   (18.57%),   and   vitamin   E   (11.37%).   Three   major  compounds  were  identified  in  O.  sanctum:  phenol,2-­methoxy-­3-­(2-­ propenyl)   (15.32%),   9,12,15-­octadecatrienoic   acid,(Z,Z,Z)-­   (16.94%),   and  9,12,15-­octadecatrienoic  acid,  methyl  ester,(Z,Z,Z)-­  (22.05%).  Three   major   compounds   were   identified   in   the   mixed   extract:   n-­hexadecanoic   acid  (16.58%),  phenol,2-­methoxy-­3-­(2-­propenyl)  (20.62%),  and  9,12,15-­ octadecatrienoic   acid,(Z,Z,Z)   (25.98%).   Four   of   the   compounds   in   the   mixed   extract   were   new:   eudesma-­4(14),11-­diene   (0.18%),   6-­ azabicyclo[3.2.1]octane   (0.51%),   cyclohexane,1-­ethyl-­1-­methyl-­2,4-­ bis(1-­methylenyl)-­,[1S-­␣␣␣␣␣␣␣␣␣␣␣-­␣-­Elemen   (0.77%),   and   globulol   (1.45%).   The   mixed   extract   had   a   high   level   of   antimicrobial   activity   against   fish   pathogens   as   indicated   by   zone   of   inhibition,   minimum   inhibitory  concentration,  and  minimum  bactericidal  concentration.
Culturing Seahorse (Hippocampus barbouri) in Illuminated Cages with Supplementary Acetes Feeding
Authors: Garcia Luis Maria B. , Hilomen-Garcia Grace V. , Calibara Ralph Laurence M.
Published: February 2021

Juvenile Hippocampus barbouri were grown in illuminated cages with or without supplemental daytime feeding of thawed Acetes (a planktonic marine crustacean), or in non-illuminated cages with Acetes feeding, as a supplement to light-attracted zooplankton prey. After ten weeks, seahorses in illuminated cages fed Acetes had the highest mean body weight (2.24 g) and length (8.20 cm), but these did not significantly differ from seahorses in unfed illuminated cages (1.88 g; 7.25 cm), which did not significantly differ from those in fed non-illuminated cages (0.88 g; 6.32 cm). In all treatments, the mean instantaneous growth rate in body weight declined progressively throughout the test but the instantaneous growth rate in stretched length did not vary. Mean survival (76-100%) of seahorses in fed non-illuminated cages and in unfed illuminated cages did not vary significantly over the test period. The mean survival of seahorses in fed illuminated cages was lowest (54%), but did not significantly differ from the other treatments. Juvenile H. barbouri grown in illuminated cages had better growth than those in non-illuminated cages, but survival was reduced when seahorses in illuminated cages were fed Acetes.
Genetics Features of Natural and Cultured Populations of Half-Smooth Tongue Sole (Cynoglossus semilaevis) Revealed by RAPD Markers
Authors: Liu Yun-Guo , Gao Huan , Liu Chun-Ying , Li Fang-Zheng , Chen Song-Lin
Published: February 2021

Randomly amplified polymorphism DNA (RAPD) was used to evaluate genetic diversity in natural and cultured populations of half-smooth tongue sole (Cynoglossus semilaevis). Two hundred genotypes from four natural populations (Laizhou, Weihai, Qingdao, Rizhao) and one cultured population (Mingbo) were screened with 18 RAPD primers. Of 101 loci in the five populations, 43.33%, 47.52%, 45.83%, 44.57%, and 42.86%, respectively, were polymorphic. The number of polymorphic loci detected by a single primer combination ranged 1-4. Average heterozygosity was 0.0735, 0.0893, 0.0871, 0.0847, and 0.0685, respectively. Weihai had greater genetic diversity than the other populations (p<0.05) including number of RAPD bands, number of polymorphic bands, average heterozygosity, and number of genotypes. Mingbo had the least genetic viability. Intentional or accidental release of cultured half-smooth tongue sole into natural sea areas may disrupt local gene pools and result in loss of genetic variability. Genetic variability of cultured populations should be monitored to conserve natural half-smooth tongue sole resources.
Comparison of Growth in Pike-Perch (Sander lucioperca) and Hybrids of Pike-Perch (S. lucioperca) × Volga Pike-Perch (S. volgensis)
Authors: Müller T. , Bódis M. , Urbányi B. , Bercsényi M.
Published: February 2021

Growth of intensively cultured pike-perch Sander lucioperca (L.) and hybrids of pike-perch females × Volga pike-perch (S. volgensis Gmelin, 1789) males (1.75 g) were compared in a 35-day experiment. Fish were sorted into three groups (50 fish/aquarium): S. lucioperca grown separately (Group P), hybrids grown separately (Group H), and a mixed group of 25 S. lucioperca (Group Mp) grown together with 25 hybrids (Group Mh). The stocking density was 0.44 g/l. Final body weights were 6.83 g, 6.54 g, 5.17 g, and 4.84 g, and specific growth rates were 3.9%/day, 3.75%/day, 3.1%/day, and 2.89%/day, for groups Mp, P, Mh, and H, respectively. The weight, length, and specific growth rates of the S. lucioperca were significantly higher (p<0.05) than those of the hybrids, whether grown separately or together. The feed conversion rate of the hybrids grown separately was significantly higher (1.28 g/g) than all other groups. Further investigation is needed to study the growth performance of larger hybrids, to compare the hybrid with S. volgensis, and to investigate the possibility of cross hybridization.
Effects of Dietary Manganese Supplementation on Antioxidant Enzyme Activity in the Shrimp (Neocaridina heteropoda)
Authors: Wang Hong-Wei , Cai Duan-Bo , Zhao Chun-Long , Xiao Guo-Hua , Wang Zi-Hui , Xu Hai-Ming , Yang Li-Kun , Ma Liang , Ma Jin-Liang
Published: February 2021

The effects of the manganese (Mn) supplemented diets on the level of superoxide anions (O-2) in the hemolymph, and the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) in the muscle of Neocaridina heteropoda were investigated. Manganese sulfate (MnSO4) was added to a basal diet at 0, 20, 40, 60, 80, or 100 μg/g. Diets were fed to triplicate groups of shrimp (0.30±0.11 g, 1.4±0.1 cm) in a recirculating freshwater rearing system for 30 days. The Mn concentration in the rearing water, monitored during feeding, was 1.00±0.02 μg/l. O-2 was lower and antioxidant enzyme activity was higher (p<0.05) in shrimps fed Mn-supplemented diets than in shrimps fed the control. Antioxidant enzyme activity reached a maximum when the Mn concentration was 60 μg/g diet.
Replacement of Fishmeal Using Poultry Offal Meal in Practical Feeds for Fry of the African Catfish (Clarias gariepinus)
Authors: Falaye A.E. , Omoike A. , Ajani E.K. , Kolawole O.T.
Published: February 2021

A 70-day feeding trial was conducted to test the effect of partial replacement of fishmeal by poultry offal in the diet for fry of the African catfish, Clarias gariepinus. Four isonitrogenous rations containing replacement of 0 (control), 30%, 60%, or 90% fishmeal by poultry offal were fed to three replicate groups of C. gariepinus fingerlings (0.74 g). Growth performance and nutrient utilization of the fish were evaluated based on weight gain, protein intake, protein efficiency ratio, specific growth ratio, gross efficiency of food conversion, and carcass analysis. The average weight gains of fingerlings fed the control (2.43 g) and 30% replacement diet (2.31 g) were higher than in fish fed the 60% (2.09 g) and 90% (2.0 g) replacement diets. The feed conversion ratio (1.48-1.62) was lowest in fish fed the control diet and highest in fish fed the 90% replacement diet. The specific growth rate, protein efficiency ratio, and apparent net protein utilization significantly decreased (p<0.05) as the level of dietary poultry offal increased. It was concluded that replacement of up to 30% fishmeal by chicken offal meal enhances growth performance of C. gariepinus fry.
Effects of Dietary Pelargonium sidoides Extract on Growth Performance in Common Carp, Cyprinus carpio
Authors: Turan Funda , Gezer Armağan , Bircan-Yildirim Yasemin
Published: February 2021

The effects of graded dietary supplementation of Pelargonium sidoides extract on growth performance, feed utilization, and body composition in common carp, Cyprinus carpio, were preliminarily evaluated. Fish (0.67±0.05 g) were fed experimental diets containing 0, 1, 3, or 5 ml/100 g P. sidoides extract for 90 days. Growth rate significantly (p<0.05) increased in carp fed supplemented diets. The specific growth rate ranged from 2.87±0.09 in the control to 3.41±0.11 in fish fed the diet supplemented with 5 ml P. sidoides. The feed conversion ratio, protein efficiency ratio, and apparent net protein utilization were significantly better in groups fed diets with 3 or 5 ml P. sidoides extract than in the control or 1 ml group. The highest protein content (19.65%) was obtained with 3 ml supplementation. The present study shows that P. sidoides extract has a positive effect on carp growth and feed utilization with no apparent effects on health status.
Population Growth of Bosmina longirostris Fed Chlorella vulgaris and Scenedesmus subspicatus in Different Densities
Authors: Ertan Ömer Osman , Güçlü Zekiye , Erdoğan Ömer , Savaş Sevgi , Gülle İskender
Published: February 2021

In this study, the effects of the different densities of Chlorella vulgaris (0.05 x 106, 0.1 x 106, 0.2 x 106, 0.4 x 106, or 0.8 x 106 cells/ml) and Scenedesmus subspicatus (0.05 x 106, 0.1 x 106, 0.2 x 106, or 0.4 x 106 cells/ml) on culture of the water flea, Bosmina longirostris, were investigated. The experiment was carried out in a photoperiod of 16 h light:8 h dark at 25±1°C. At the beginning of the experiment, one B. longirostris individual (<24 h old) was put into each vessel, and the number of individuals and rate of population increase were determined for 30 days. Increasing the food density increased the number of individuals and the rate of population. The maximum number of B. longirostris individuals (7.1±2.08 ind/ml) and maximum rate of population increase (0.2±0.004/day) was in the group fed 0.2 x 106 cells/ml S. subspicatus. The effect on the number of the individuals was statistically significant (p<0.05).
Improving Salinity Tolerance in Tilapias: Past Experience and Future Prospects
Authors: Hulata Gideon , Cnaani Avner
Published: February 2021

With increasing scarcity of fresh water available for aquaculture, especially in arid regions, development of tilapias that tolerate high salinity would increase fish (and hence, animal protein) production. We review culture practices, nutrition, physiology, and genetics, and propose approaches to improving salinity tolerance in tilapias. Physiological studies of biochemical pathways underlying phenotypic differences in salt tolerance can lead to genetic studies of intra and interspecific variation. Molecular technology can lead to studies on osmoregulation-related biochemical pathways, for which the euryhaline tilapia is an attractive model. Functional genomics and proteomics are powerful tools for studying the molecular bases of environmental adaptation and metabolic connections to osmoregulatory physiology. Both provide avenues for discovering novel pathways related to osmoregulation with relevance to aquaculture. Dietary supplementation with NaCl and optimized acclimation protocols are immediate and practical ways to improve salt tolerance. Inter-specific variation in salinity tolerance may be used to select salt-tolerant species and develop salt-tolerant hybrids. In the long term, quantitative trait loci associated with, or genes involved in, saltwater tolerance may facilitate marker-assisted or gene-assisted selection for this trait in tilapia.
Effect of Dietary Canola Oil Level on Fatty Acid Composition of Rainbow Trout (Oncorhynchus mykiss L.)
Authors: Dernekbaşi Seval , Karayücel İsmihan , Öksüz Abdullah
Published: February 2021

The effects of different levels of dietary canola oil on fatty acid composition of rainbow trout (Oncorhynchus mykiss) were investigated. Five experimental diets with equal protein (47%) and lipid (17%) contents were formulated for rainbow trout with a mean weight of 119±0.17 g. Canola oil was used to replace 0, 25%, 50%, 75%, or 100% of the fish oil in the control diet. Fish were fed twice daily to satiation for 70 days. At the end of the study, fatty acid compositions in the trout body mirrored the fatty acid compositions of the experimental diets. The highest fatty acids were palmitic acid (C16:0), oleic acid (C18:1n-9), linoleic acid (C18:2n-6), and docosahexaenoic acids (C22:6n-3). The study showed that, under our test conditions, canola oil can replace 100% of fish oil with no negative effect on the chemical or fatty acid composition of rainbow trout.
Efficacy of an Inactivated Vaccine and Nutritional Additives Against White Spot Syndrome Virus (WSSV) in Shrimp (Penaeus monodon)
Authors: Amar Edgar C. , Faisan Joseph P. Jr.
Published: February 2021

Although the immune system of shrimps is not comparable to that of vertebrates, shrimps can acquire protection against pathogenic challenge by building up immunity. In this study, formalin-inactivated virus (FIV) was administered by injection, bath-immersion, or orally to determine levels of vaccination-mediated protection against the pathogenic white spot syndrome virus (WSSV). Diets supplemented with alfalfa, methyl sulfonyl methane (MSM), or wheat grass were provided with or without FIV. Shrimp injected with FIV and challenged 3, 15, or 30 days after vaccination had cumulative and relative survivals of 83%, 67%, and 33%, respectively. Survival of shrimp challenged by bath-immersion 3-45 days after vaccination by immersion was significantly higher than in the unvaccinated control. Orally vaccinated shrimp challenged by bath-immersion were partially protected up to 45 days after vaccination (cumulative survival 63.7%, relative 61.7%) but not til 60 days after vaccination (cumulative 8%, relative 3.2%). Survival of unvaccinated shrimp challenged by bath-immersion improved when shrimp were fed a diet supplemented with wheat grass or MSM, but not alfalfa. Survival was further enhanced when FIV was provided together with diets supplemented with wheat grass (cumulative 72.7%, relative 94.8%) or MSM (cumulative 73.3%, relative 96.3%).
Effect of Glycerol on Fertility of Cryopreserved Grass Carp (Ctenopharyngodon idella) Sperm
Authors: Bozkurt Yusuf , Yavaş İlker , Öğretmen Fatih , Sivaslıgil Buğra , Karaca Fikret
Published: February 2021

This research investigated the effect of adding glycerol to different ionic extenders on motility and fertilizing ability of frozen-thawed sperm of grass carp (Ctenopharyngodon idella) under hatchery conditions. Semen was collected by abdominal stripping from adult males and diluted to a ratio of 1:3 in Kurokura I or Kurokura II extender containing 10%, 15%, or 20% glycerol. Diluted semen was packaged in 0.5-ml straws and left to equilibrate for 30 min at 4°C. Following equilibration, the straws were exposed to liquid nitrogen vapor for 10 min and plunged into liquid nitrogen (-196°C). Straws were thawed in a water bath at 30°C for 10 s to determine the post-thaw motility and movement duration. The spermatozoa:egg ratio in fertilization experiments was 1 x 105:1. The highest mean fertilization rate (95.63±0.52; p>0.05) was obtained with semen frozen in Kurokura I extender containing 10% glycerol. Results indicate that grass carp sperm can be successfully cryopreserved with ionic extenders containing glycerol at 10-20%.
Evaluation of Autotrophic and Heterotrophic Microcosm-based Systems on the Production Response of Litopenaeus vannamei Intensively Nursed without Artemia and with Zero Water Exchange
Authors: Becerra-Dórame M.J. , Martínez-Córdova L.R. , Martínez-Porchas M. , Lopez-Elías J.A.
Published: February 2021

An experiment was conducted for 28 days to evaluate the productive response of the Pacific white shrimp (Litopenaeus vannamei) postlarvae, intensively nursed in autotrophic or heterotrophic microcosm-based treatments, without Artemia and zero water exchange. The autotrophic system was based on the promotion of microalgae as the main primary producers. The heterotrophic system was based on the promotion of bacteria as the main primary producers. The control was fed a conventional diet. Bioflocs and biofilms were used to promote biota in the autotrophic and heterotrophic systems. There were no differences in temperature, salinity, or DO among treatments. The chlorophyll a concentration and microalgae density were much greater in the control and autotrophic system than in the heterotrophic. The concentration of heterotrophic bacteria was significantly higher in the heterotrophic than in the autotrophic system and control. Individual weight gain was higher in the control (81±2 mg) and heterotrophic (77±8 mg) treatments than in the autotrophic (58±10 mg) but survival was better in the autotrophic (86%) than control (77%) and heterotrophic (76%) treatments. Final biomass was statistically similar in all treatments, as well as the feed conversion ratio which ranged from 0.65 (heterotrophic) to 0.69 (autotrophic). The increased natural productivity caused a positive productive response in the shrimp postlarvae. Such strategies can be an adequate alternative when Artemia is unavailable.
Replacement of Fishmeal by Rapeseed Protein Concentrate in Diets for Common Carp (Cyprinus carpio L.)
Authors: Slawski Hanno , Adem Halime , Tressel Ralf-Peter , Wysujack Klaus , Koops Udo , Schulz Carsten
Published: February 2021

The potential of rapeseed protein concentrate as an alternative to fishmeal in diets for common carp (initial average weight 26.7±0.8 g) was evaluated. Triplicate groups of fish were fed isonitrogenous (40.4±0.2% crude protein) and isocaloric (21.4±0.1 kJ/g) experimental diets with 0%, 33%, 66%, or 100% replacement of fishmeal by rapeseed protein concentrate. At the end of the 56-day feeding period, growth parameters and feed efficiencies did not significantly differ between fish fed the 0% and 33% diets. The 66% and 100% replacement diets led to reduced feed intake and feed efficiency, resulting in lower growth performance. It appears that the taste and amino acid profile of these diets were negatively affected by the high inclusion levels of rapeseed protein concentrate. In conclusion, rapeseed protein concentrate can effectively replace 33% of the fishmeal in diets for carp without using palatability enhancers or amino acid supplements.
Offshore Farming of the Mediterranean Amberjack (Seriola dumerili) in the Northeastern Mediterranean
Authors: Yilmaz Erdal , Şereflişan Hülya
Published: February 2021

The growth rate, survival, and feeding parameters of Mediterranean amberjack (Seriola dumerili Risso, 1810) cultivated in offshore cages in the Gulf of İskenderun (Hatay, Turkey) were investigated from July 2006 to March 2008. Two offshore cages (339 m3) were placed at a depth of 10 m in a sheltered area 500 m off the coast. Juveniles (101.97±14.54 g), caught with seine nets 400-1200 m from the coast, were stocked in the cages at 250 per cage. Fish in one cage, Group A, were fed commercial pellets for all 20 months whilst fish in the second cage, Group B, were fed pellets for the first 16 months and frozen sardines for the following four. The mean live weight, survival, feed conversion ratio, daily feed consumption, and water quality parameters were recorded monthly. Group B reached a significantly (p<0.05) greater weight (2785.00±64.91 g) than Group A (2441.14±38.13 g). Food conversion ratios ranged 1.16-2.46 for group A and 1.10-2.28 for group B, low when compared with other studies on amberjacks in the Mediterranean. Average mortality was 25%, due to a Zeuxapta seriolae (Monogenea: Heteraxinidae) infection in December 2006 (20%) and fish handling for measurement in June 2007 (~5%). The farmed amberjacks had significantly higher protein and lipid contents than their wild counterparts at the end of the 20-month feeding period. Amberjacks found frozen sardines more appealing than pellets, especially during the winter. In conclusion, it is advised to feed Mediterranean amberjack frozen sardines or other trash fish during the winter grow-out period. Their rapid growth rate, as well as their adaptability to farming, make offshore net cages a promising system for the aquaculture of this species.
Effect of Dietary Selenium Supplementation on Cirrhinus mrigala (Hamilton, 1822) Reared in Copper and/or Cadmium Contaminated Water
Authors: James Raja
Published: February 2021

The effect of selenium supplementation at 0, 75, 150, 225, and 300 mg/kg diet on reduction of copper and/or cadmium toxicity was studied in a freshwater cultivated carp, Cirrhinus mrigala. Food utilization, selected hematological parameters, oxygen consumption, and metal concentrations in the fish body and fecal matter were analyzed. The 96-h LC50 values for C. mrigala were 0.126 ppm for copper exposure, 0.563 ppm for cadmium, and 0.123 ppm for exposure to both metals simultaneously. Sublethal exposures to the metals significantly reduced consumption and growth rates, hematological parameters, and oxygen consumption in fish fed the unsupplemented diet. Equitoxic exposure of copper and cadmium together drastically reduced the physiological parameters as compared to individual exposure to either one of the metals. However, dietary selenium supplementation significantly improved the tested physiological parameters and reduced the metal burden in the fish body. Metal elimination from the body took place through the feces. Supplementation of 75 and 225 mg selenium per kg diet was required to reduce copper and cadmium toxicity when the metals existed individually in the environment. However, 300 mg selenium per kg diet was required to reduce toxicity when both metals were present together in the environment.
Nibbling Frequency of Carps in Periphyton-Based Aquaculture Systems with and without Supplemental Feed
Authors: Rai Sunila , Yi Yang
Published: February 2021

The nibbling frequency of five carp species (rohu Labeo rohita, mrigal Cirrhinus mrigala, catla Catla catla, common carp Cyprinus carpio, silver carp Hypophthalmichthys molitrix) on bamboo lateral sticks (kanchi) colonized by periphyton was examined in fed and unfed systems. There were three treatments: (a) no carp and no supplemental feed (control), (b) carp without supplemental feeding (unfed treatment), and (c) carp with supplemental feeding (fed treatment). For 12 h (07:30-19:30) during six days, nibbling behavior was observed in real time via a digital video camera and recorded on a camcorder for later viewing. Rohu, catla, and common carp nibbled on the kanchi, while mrigal and silver carp did not. In rohu and catla, the nibbling frequency was significantly higher in the unfed treatment than in the fed treatment (p<0.05); supplemental feeding reduced nibbling frequency by 81% and 91%, respectively. Hence, in periphyton-based aquaculture systems, there is no need for a high density of substrates in ponds that receive supplemental feed. Alternatively, the amount of supplied feed can be reduced to force these species to consume more periphyton.
Stress Survival in Larvae of Florida Pompano (Trachinotus carolinus) Fed Enriched Rotifers (Brachionus plicatilis) and Nauplii of the Calanoid Copepod (Pseudodiaptomus pelagicus)
Authors: Cassiano Eric J. , Ohs Cortney L. , DiMaggio Matthew A.
Published: February 2021

The Florida pompano, Trachinotus carolinus, is a highly prized marine fish whose larviculture includes the feeding of live rotifers and brine shrimp nauplii. In a previous study, growth and survival of pompano larvae fed nauplii of the calanoid copepod, Pseudodiaptomus pelagicus, were compared to those of larvae fed enriched rotifers, Brachionus plicatilis. There were advantages to including the copepod in the larvae diet. The current study examines the stress tolerance of such larvae. Two trials were conducted: for seven (trial 1) and nine (trial 2) days post-hatch. Larvae were fed diets that included enriched rotifers and/or P. pelagicus nauplii and subjected to varying durations of air exposure (‘sieve stress’). Larvae fed copepods exhibited significantly greater stress tolerance than larvae fed only enriched rotifers. In trial 1, stress tolerance increased as the number of days on which copepods were fed increased. It is possible that stress tolerance improved because of a better nutritional profile of the copepod nauplii.
Low Mercury Levels in Lake Kinneret Fish
Authors: Blanchfield Paul J. , Shapiro James , Sukenik Assaf , Orihel Diane M. , Shefer Edna
Published: February 2021

Human exposure to the neurotoxin, methylmercury (MeHg), occurs primarily through the consumption of contaminated fish that are present even in pristine freshwater ecosystems. Lake Kinneret is the sole freshwater lake in Israel and supports an important commercial fishery. We examined total mercury (THg; often equivalent to MeHg in fish muscle tissue) for nine fish species in Lake Kinneret. Concentrations were low for all fish species, 6-409 ng/g, and below 500 ng/g MeHg, the level generally considered safe for human consumption. Of particular relevance are the very low levels of THg (<60 ng/g) in Galilee St. Peter’s fish (Sarotherodon galilaeus) and lavnun (Acanthobrama terrascantae), the most commercially important species in Lake Kinneret. Biomagnification was apparent among trophic guilds, with THg concentrations increasing from primary to secondary to tertiary consumers. This study suggests that consumption of commercial species, especially primary consumers, will result in low MeHg exposure to humans.