Volume 66, 2014

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Dietary Copper Requirement of Juvenile Oriental River Prawn Macrobrachium nipponense, and its Effects on Growth, Antioxidant Activities, and Resistance to Aeromonas hydrophila
(2014) Kong, You-Qin; Ding, Zhi-Li; Du, Zhen-Yu; Sun, Sheng-Ming; Wang, Li-Gai; Li, Er-Chao; Chen, LI-Qiao
The present experiment evaluated the effects of dietary copper (Cu) on growth, antioxidant activities, and susceptibility to Aeromonas hydrophila infection of juvenile Oriental river prawn Macrobrachium nipponense, as well as determining the optimal dietary copper requirement. Semi-purified diets containing seven graded levels of copper (2.8, 12.2, 20.9, 29.8, 43.1, 78.9 and 157.1 mg/kg diet) from CuSO4⋅5H2O were fed to juvenile prawn (initial weight 0.101±0.002 g). The weight gain of prawns fed with 2.8-78.9 mg/kg Cu was higher and they had lower feed conversion ratios than the group fed 157.1 mg/kg Cu. Cu concentrations in the hepatopancreas, muscle, and whole body in prawns tended to increase with increased dietary Cu concentration. Hepatopancreas Cu-Zn superoxide dismutase (Cu-Zn SOD) activity, glutathione peroxidase (GPx), and total antioxidant competence (T-AOC) were highest (P<0.05) in the 43.1 mg/kg Cu group. The hepatopancreas malondialdehyde (MDA) content was lower (P<0.05) in the prawns fed 29.8 mg/kg Cu than that in prawns fed 2.8, 12.2, 78.9 and 157.1 mg/kg Cu. After the feeding experiment, prawns were injected with A. hydrophila, and the cumulative mortality rate of the prawns fed with 20.9-43.1 mg/kg Cu was lower than the prawns fed with 2.8 and 157.1 mg/kg Cu. The optimum requirement of dietary Cu in juvenile prawns was estimated at 26.9-27.8 mg/kg diet based on cumulative mortality rate and whole-body Cu retention.
Vitrification of Common Carp (Cyprinus Carpio) Spermatozoa, Post-Thaw Sperm Quality, and Fertility
(2014) Bozkurt, Yusuf; Yıldız, Cengiz; Yavaş, İlker
The aim of this investigation was to test a new technology, vitrification, or ultra-rapid freezing of the spermatozoa of common carp, and to study the ability of glucose, BSA, and other cryoprotectants to protect these cells from cryo-injuries. Spermatozoa were isolated and vitrified using 10 different cryoprotectant solutions: (1) Glucose based medium (GBM) + 1% bovine serum albumin (BSA); (2) GBM + 1% BSA + 10% DMSO; (3) GBM + 1% BSA + 20% DMSO; (4) GBM + 1% BSA + 30% DMSO; (5) GBM + 1% BSA + 10% DMA; (6) GBM + 1% BSA + 20% DMA; (7) GBM + 1% BSA + 30% DMA; (8) GBM + 1% BSA + 10% methanol; (9) GBM + 1% BSA + 20% methanol; (10) GBM + 1% BSA + 30% methanol. Fertilization rates for vitrification experiments were low and the use of low concentrations of cryoprotectants yielded lower fertilization rates than the vitrification solutions containing high cryoprotectant concentrations. In conclusion, this study reported successful vitrification of common carp spermatozoa by direct transfer into liquid nitrogen.
Effect of Enzyme Supplementation to Soybean Meal Based Diets on Growth, Feed Conversion Ratio, Nutrient Digestibility, and Body Composition of Rainbow Trout Oncorhynchus mykiss, (Walbaum) Fry
(2014) Yigi, Nalan Ozgur; CiHangir, Esra; Metin, Selin; Koca, Seval Bahadir
A 12 week feeding trial was conducted with rainbow trout Oncorhynchus mykiss, fry (3.98 ± 0.05 g, average initial weight) to determine the effects of supplemental exogenous enzymes on growth, digestibility, and body composition. Five diets were prepared adding pectinase, xylanase, cellulase enzymes, and a commercial enzyme complex, to diets containing 40% soybean meal. The experiment was conducted in triplicate in 15 tanks, each stocked with 45 juvenile fish. The results showed that addition of enzymes to diet containing 40% soybean meal had no significant effect on growth performance and feed conversion ratio. No significant differences were observed in the apparent lipid digestibility, apparent protein digestibility, and whole body composition among dietary treatments (P>0.05). In conclusion, the use of single or multi-components of commercial enzymes (tested in this case) are not sufficient to degrade the high levels of non-starch polysaccharides introduced into digestive tract by the diets containing soybean meal at the rate of 40%.
Effects of Mannan Oligosaccharide (MOS) on the Survival, Physiological, and Immunological Response of the Black Tiger Prawn (Penaeus monodon Fabricius, 1798) when Challenged with two Different Stressors
(2014) Sang, Huynh Minh; Thuy, Nguyen Thi Thanh
Two trials were conducted to determine the effects of mannan oligosaccharide (MOS) on the resistance of the black tiger prawn (Penaeus monodon) to two different stressors, bacterial infection by Vibrio alginolyticus, and the environmental pollutant ammonia (NH3). Prawns were fed two different diets, 0% (control diet) and 0.15% MOS, for 8 weeks prior to exposure to the stressors. They were then tested for survival, physiological, and immunological parameters, as indicators of health status. When the two groups were exposed to NH3 and bacterial infection, survival of prawns fed the MOS diet was significantly higher (P<0.05) than prawns fed the control diet. Similarly, the wet hepatosomatic index (Hiw), dry hepatosomatic index (Hid), hepatopancreatic moisture content (HM), total hemocyte count (THC), and granular cell percentage (GC%), of the MOS fed prawns was significantly higher (P<0.05) than in prawns fed the control diet. Bacteremia of the MOS fed prawns was lower (P<0.05) than the control diet-fed prawns after bacterial infection. Findings demonstrated the potential of MOS to improve the survival, health status, and immunity of black tiger prawns when challenged with bacterial infection and NH3 exposure.
Effects of Dietary Emodin Supplementation on Growth Performance, Non-Specific Immune Responses, and Disease Resistance to Aeromonas hydrophila in Juvenile Wuchang Bream (Megalobrama amblycephala)
(2014) Zhang, Yuan-yuan; Liu, Bo; Ge, Xian-ping; Liu, Wen-bin; Xie, Jun; Ren, Ming-chun; Zhou, Qun-lan; Sun, Sheng-ming; Cui, Yan-ting; Chen, Ru-li; Pan, Liang-kun
An 8-week feeding trial was conducted to investigate the effects of dietary emodin supplementation on growth, non-specific immunity, and protection against Aeromonas hydrophila infection in juvenile Megalobrama amblycephala. A basal diet was supplemented with 0 (control), 15, 30, 60 and 120 mg emodin/kg to formulate five experimental diets. Each diet was randomly allocated to triplicate tanks of ﬁsh in a circulating water system (initial average weight 3.49±0.045g, 25 fish per tank). At the end of the feeding trial, fish fed the diet supplemented with 0 and 120 mg emodin/kg had lower weight gain (WG) and speciﬁc growth rate (SGR) than those in the other treatment groups, but no significant differences were observed among diets supplemented with emodin from 15 to 60 mg/kg. A significant increase on feed conversion ratio (FCR) of fish fed diet supplemented with 120 mg emodin/kg was observed. The white blood cell count (WBC), respiratory burst activity, superoxide dismutase (SOD) activity, myeloperoxidase (MPO) activity, malondialdehyde (MDA) content, and tumor necrosis factor-α (TNF-α) activity first increased and then decreased with increase of the dietary emodin levels. Fish fed the 30 mg emodin/kg supplemented diet had higher WBC, respiratory burst activity, SOD and TNF-α activity, and lower MDA content, than fish fed diets supplemented with 0 and 120 mg emodin/kg. In the bacteria challenge experiment with A. hydrophila, fish fed a diet supplemented with 30 and 60 mg/kg had a lower cumulative mortality rate than the control group. These results indicated that appropriate dietary emodin supplementation (especially 30 mg emodin/kg diet) could enhance the growth and immune responses of ﬁsh and improve resistance to infection by A. hydrophila.
Use of Lactic Acid Bacteria from Nile tilapia Oreochromis niloticus as Probiotics for Sustainable Production and Improvement in Fish Welfare
(2014) L.C, Nwanna; Ajani, E. K.; Bamidele, S. F.
Two studies were conducted to investigate the effectiveness of lactic acid bacteria (LAB) from the intestine, gills, and skin of Nile tilapia Oreochromis niloticus as probiotics to promote growth, bolster the immune system, and improve general fish welfare. Results of the first study including LAB characterization indicated four major strains in the three organs as Lactobacillus fermentum (60.0%), L. brevis (16.7%), L. acidophilus (13.3%) and L. xylosus (10.0%). Safety tests of these LAB isolates conducted on some samples of the fish confirmed that they were non-pathogenic. In the second study L. fermentum, which showed the greatest promise as a probiotic, was used at different dilution levels to prepare diets for feeding O. niloticus juveniles weighing 18.1±0.1g. Diets 1-5 contained 0 colony forming unit (cfu)/g, 103cfu/g, 105cfu/g, 107cfu/g and 109cfu/g of L. fermentum, respectively. The feeding trials in fish fed diets 1-5, resulted in growth from the initial weight of 18.1g to 32.0e, 46.0a, 44.3b, 43.9c and 40.8d g, respectively. Inclusion of L. fermentum in the diets increased carcass protein, pack cell volume, hemoglobin, RBC, and reduced glutamate (P<0.05). Challenge tests conducted on the fish using pathogenic Pseudomonas aeruginosa indicated that the diets supplemented with L. fermentum improved fish immune responses. In conclusion, the studies revealed that LAB from O. niloticus can act as probiotics to improve growth, immune responses, and fish welfare.
Comparative Study of Antibacterial Properties of Emodin and Enrofloxacin Against Aeromonas hydrophila
(2014) Ren, Mingchun; Chen, Ruli; Zhou, Qunlan; Pan, Liangkun
Antibacterial properties of emodin, extracted from rhubarb, and enrofloxacin, against Aeromonas hydrophila, were assessed in this study. The minimum inhibitory concentration (MIC) values of emodin and enrofloxacin to fight A. hydrophila WJ2011BJ44 were found to be 100ug/ml and 9.375ug/ml, respectively. To understand the mechanisms of action of emodin and enrofloxcain against A. hydrophila we studied antibacterial activity, bacterial membrane permeability, and ultrastructure of A. hydrophila cells treated with emodin, enrofloxacin individually, and the combination of both. The results shown in the growth curve of A. hydrophila treated with different concentrations (from 0 MIC to 4 MIC) of emodin and enrofloxacin were similar and stable, and there was no significant difference in the growth curve of different treatment groups. There were significant differences in the K+ concentration among all treatment groups from 1 h to 8 h after incubation compared with the control. The highest K+ concentration was observed in the emodin+enrofloxacin group from 1 h to 8 h after incubation. PI fluorescence signal of untreated A. hydrophila cells and A. hydrophila cells treated with emodin, or enrofloxacin individually, or the combination of both were 0.89, 11.4, 13.98 and 18.3, respectively. The mortality of A. hydrophila cells treated with the combination of emodin and enrofloxacin was greatest compared with other groups. These results indicated that 2 MIC emodin, 2 MIC enroflxacin, and combination of 1 MIC emodin and 1 MIC enrofloxacin can inhibit the growth of A. hydrophila, increase bacterial membrane permeability, and damage cell membrane integrity. The combination of 1 MIC concentration emodin and 1 MIC concentration enrofloxacin produced the best antibacterial activity against A. hydrophila *
Effect of Feeding Frequency on Growth Rate, Body Composition and Gastric Evacuation of Juvenile GIFT Strain of Nile Tilapia (Oreochromis niloticus)
(2014) Bin, Chen; Qi, Peng; Bin, Wu; Bo, Luo; Wen, Liang $Jian, Feng
The specific objectives of this study were to determine the optimum feeding frequency in juvenile GIFT (Genetically Improved Farmed Tilapia) strain of Nile tilapia (Oreochromis niloticus), for growth rate, body composition, and gastric evacuation, as well as to investigate the passage of a single meal through the stomach in order to establish gastric evacuation rate. Six treatment groups of juvenile GIFT were fed to satiation with extruded feed, at 6 feeding frequencies: four, three, and two meals a day, and four meals, three, and two meals, every 2 days, for 6 weeks respectively. Each treatment (n=20) was replicated three times. As feeding frequency decreased, the growth rate of the juvenile GIFT decreased gradually. The feed intake of fish fed two meals a day was significantly lower than that of fish fed three meals a day (P <0.05), whereas the feed efficiency ratio of fish fed two meals a day was significantly higher than that of fish fed three meals a day (P<0.05). As feeding frequency decreased, moisture content of fish body increased and the fat and protein contents decreased gradually. Hepatosomatic indices of fish fed two, and three meals a day, were not statistically different to each other or to the remaining groups. The livers of all fish were normal. Gastric evacuation of the fish was best evaluated with the square root model. It was estimated that gastric feed contents gradually decreased and reached the prefeeding level within 15 h. Evacuation of 80% would require 9 h which appeared to correspond with the return of appetite. Our results suggest that two meals a day are optimal for growth performance of juvenile GIFT Nile tilapia.
Growth and Hemato-Immunological Response to Dietary i-Carrageenan in Labeo rohita (Hamilton, 1822) Juveniles
(2014) Kumar, Vikash; Kumar, Saurav; Pandey, P.K.; Raman, R.P.; Prasad, K. Pani; Roy, Suvra; Kumar, Abhay; Kumar, Kundan
The study was performed over a period of 60 days to evaluate the effect of dietary carrageenan on growth, hematology, biochemistry, and innate immunity in rohu Labeo rohita. A basal diet supplemented with iota (i)Carrageenan at 5, 10 and 20g/kg was fed to three different groups of fish for 60 days. The fish were examined 15, 30, 45, and 60 days after commencement of the study. Parameters for growth (absolute growth, specific growth rate, and percentage weight gain), hematology (total erythrocyte count, total leucocyte count, thrombocyte count and hemoglobin value), biochemistry (total serum protein, albumin, globulin and albuminglobulin ratio), and innate immunity (nitroblue tetrazolium NBT, and myeloperoxidase MPO, activity) were monitored to assess the effect of the iCarrageenan based diet in L. rohita. All the parameters examined (growth, hematology, biochemistry, and innate immunity) increased significantly (P<0.05) in carrageenan-fed groups compared to the control group. However, the highest values for those parameters were found on the 60th day in the group which was fed a 10 g/kg i-Carrageenan diet. The study suggests that a 10 g/kg diet of i-carrageenan enhances immunity and the overall health status in L. rohita.
Chemical composition and fatty acid profile of Trans-Andean Shovelnose catfish Sorubim cuspicaudus
(2014) Prieto-Guevara, Martha Janeth; Pájaro, Cristina Morelo; Doria, Yuly Yabrudy; Atencio-Garcia, VictorJulio
Chemical composition and fatty acid profile were studied in larvae and adult Trans-Andean shovelnose catfish muscle. The chemical composition in dry matter of the larvae and the food they consumed were: moisture, 89.2%, 91.8%; protein, 79.8%, 70.6%; ethereal extract, 7.8% 7.2%; and ash, 12.7% and 14.5%, respectively. In adult muscle there were no significant differences between sexes in the percentages of moisture, protein, ethereal extract, and ash. Similarly, there was no statistical difference between sexes for monounsaturated fatty acids and polyunsaturated fatty acids. A significant difference between the sexes was found in the fatty acid profile which showed a predominance of saturated fatty acids. This study demonstrated that there is a great similarity in the chemical composition of the species. The percentage of protein and variation in ethereal extract and ash content was dependent upon the composition of its food. These results provide basic information for formulating adequate nutritional diets to meet the requirements of Neotropical fish.
The Dietary L-Methionine Requirement of the Juvenile Yellow Catfish Pelteobagrus fulvidraco
(2014) Chen, Yan; Cao, Jun-Ming; Huang, Yan-Hua; Zhao, Hong-Xia; Chen, Bing; Zhu, Xuan; Lan, Han-Bing; Pan, Qing
An 8 week feeding trial was conducted to investigate the effects of dietary methionine levels on growth, feed utilization, body composition, and morphometric parameters of juvenile yellow catfish (Pelteobagrus fulvidraco), and to determine their dietary methionine requirement. Six isonitrogenous and isoenergetic diets (405.0 g/kg crude protein and 18.0 kJ/g gross energy) were formulated, and crystalline L-methionine was added to obtain dietary methionine levels of 5.5, 6.7, 7.5, 8.7, 9.5 and 11.3 g/kg dry diet. Fish with an initial weight of 1.4 g were randomly distributed into six groups and fed the respective formulated diets. Increasing amounts of dietary methionine up to 8.7 g/kg dry diet resulted in increased final body weight, rate of weight gain, specific growth rate, feed conversion efficiency and protein efficiency ratio however, a further increase in methionine level resulted in a decrease in these parameters. No significant difference in survival percentages was detected among the dietary treatments. A one-slope quadratic broken-line analysis model, based on specific growth rate and dietary methionine levels, indicated that the dietary L-methionine requirement of juvenile P. fulvidraco is 10.5 g/kg dry diet (accounting for 26.0 g/kg of dietary protein).
The Effects of Fish Meal Replacement by Yeast Based Nucleotides on Growth, Body Composition and Digestive Enzyme Activity in Rainbow Trout Juveniles (Onchorchyncus mykiss)
(2014) Hunt, Arzu Özlüer; Yılmaz, Ferbal Özkan; Engin, Kenan; Berköz, Mehmet; Gündüz, Suna Gül; Yalın, Serap; Şahin, Nefise Özlen
This 60 day study investigated the effects of organically certified nucleotide yeast-derived protein source (Nu-Pro®) on growth, feed efficiency, fillet proximate composition and digestive enzymes in rainbow trout (Onchorhyncus mykiss). Diets were isonitrogenous and isocaloric. Three experimental diets wherein 20%, 40% and 60% of the fish meal content was replaced by Nu-Pro®, were compared to the control diet in which the crude protein content was anchovy fish meal and corn gluten meal. The rainbow trout (initial weight 27 g/fish) were fed twice daily in 200-l Aqaria. Live weight gain increase ranged from 125-195% in fish fed the experimental diets. Results indicated that up to 40% fish meal protein can be replaced by Nu-Pro® without compromising growth rates, feed efficiency or the fillet biochemical composition in the rainbow trout. The effect of the dietary Nu-Pro® supplementation on digestion was partly observed by assaying the activity of pepsin, intestinal amylase, trypsin and lipase. Apart from amylase activity, results indicated that dietary supplementation of nucleotides is beneficial and may also have differential effects upon digestive enzyme activities.
Impact of Handling and Pre-Mortal Stress on the Flesh Quality of Common Carp (Cyprinus carpio L.)
(2014) Varga, Dániel; Szabó, András; Hanc, Csaba; Jeney, Zsigmond; Ardó, László; Molnár, Marcell; Molnár, Tamás
The aim of this study was to investigate stress in common carp Cyprinus carpio L. caused by harvesting, transport, and the stunning method, and the effect of the latter on flesh quality Serum cortisol concentration increased during harvesting and transport. The percussive stunning (blow on head) method caused the least stress and resulted in a significant increase in blood cortisol concentration (P<0.01). This method had no significant effect on conventional flesh quality. CO2 asphyxiation which was more stressful delayed stiffening in rigor mortis development. The greatest stress was caused by live chilling. There was a decline of pH levels in the CO2 asphyxiated and live chilled groups compared to the percussive stunned group. According to our results percussive stunning led to the best fillet quality and is the least objectionable method according to animal welfare standards.
Sperm Properties of Waigieu seaperch (Psammoperca waigiensis)
(2014) Le, Minh Hoang; Nhung, Nguyen Thi Hong; Pham, Linh Phuong
The aim of this study was to determine the semen properties of Waigieu seaperch (Psammoperca waigiensis). The physical properties of the semen were: semen volume 1.28±0.05 ml/fish, sperm density 31.35±0.67x109 cells/ml, spermatocrit 87.70±0.80%, and sperm count 40.12±1.68x109 cells/fish. The biochemical properties of the seminal plasma were 154.45±0.48 mmol/l sodium, 16.89±0.31 mmol/l potassium, 113.58±0.38 mmol/l chloride, 12.75±0.38 mmol/l calcium, 6.58±0.22 mmol/l magnesium, 1.15±0.08 g/l total protein, 346.37±2.71 mOsm/kg osmolality and 7.85±0.07 pH. Regression analysis showed a significant positive linear relationship between fish length and fish weight, sperm count and semen volume, and sperm density and spermatocrit, supporting the use of spermatocrit as a rapid estimator of sperm density in this species. Sperm motility parameters tested showed sperm motility, sperm velocity and duration of sperm motility as 95.80±0.389%, 144.50±0.96 µm/s and 232.30±2.32 s, respectively. The results from this study provide information on Waigieu seaperch sperm physiology. The values and correlations between the semen properties and the composition of seminal plasma may provide useful information for the formulating a species-specific extender solution for the cryopreservation of Waigieu seaperch sperm.
The Effect of Streptomycin on Freezing Rainbow Trout (Oncorhynchus mykiss) Sperm
(2014) Ekici, Aygül; Baran, Alper; Özdaş, Ö. Banu; Sandal, A. İzem; Yamaner, Güneş; Güven, Erdoğan; Baltacı, Muhammed Ali
Mature male and female rainbow trout (Oncorhynchus mykiss) were used to study the effect of different concentrations of streptomycin in a cryopreservation solution on the sperm motility, motility duration, and fertilization rate of rainbow trout. 300mM glucose and 10% DMSO containing diluent was used as a cryopreservation solution. Three different concentrations (3600, 7200 and 10800 μg/ml) of streptomycin were added to the diluent. Our study showed that various concentrations of streptomycin in cryopreservation solution caused a significant reduction in the percentage and duration of rainbow trout spermatozoa motility after freezing-thawing. The percentage of egg fertilization also decreased. When streptomycin-containing groups were compared with each other, a statistical difference was found (p<0.05). However, no statistical difference was observed in terms of the percentage of eyed-embryos.
Preliminary Study on Hybridization of Brown Trout (Salmo trutta macrostigma) and Rainbow Trout (Oncorhynchus mykiss) Using Cryopreserved Sperm
(2014) Bozkurt, Yusuf; Yavaş, İlker
This study examined the effect of two different extenders (carbohydrate and mineral based), supplemented with 10% Dimethyl sulfoxide (DMSO), on cryopreservation of brown trout (Salmo trutta macrostigma) sperm used for hybridization with rainbow trout (Oncorhunchus mykiss). The carbohydrate based extender resulted in higher fertilization (42.5±1.4%) than the mineral based extender and there was no difference in fertilization rates (p>0.05). This study successfully demonstrated that it is possible to produce Salmo trutta macrostigma x Oncorhynchus mykiss hybrids using cryopreserved sperm from brown trout.
Characterization of GnRH, ILGFRI and AR Genes in Sturgeon’s Genomics
(2014) Albayrak, Gülruh; Şengör, Gülgün F. Ünal; Yörük, Emre
Abstract- In this study, gonadotropin-releasing hormone (GnRH), insulin-like growth factor receptor I (ILGFRI), and androgen receptor (AR) genes coding, were examined by polymerase chain reaction (PCR) analysis and DNA sequencing in three Eurasian sturgeon species: Huso huso, Acipenser stellatus and A. gueldenstaedtii. Amplicons of 190 bp for GnRH, 180 bp for ILGFRI, and 200 bp for AR genes were amplified with specific primer pairs in all species genome. All amplification products were sequenced and compared to reference H. huso genome retrieved from NCBI database by BLASTN analysis. The ILGFRI gene had the most similar sequences (75.96-96.15%) in all species. Gene sequence similarity calculated for AR gene ranged from 48.5- 95.71%. The GnRH gene had more distant sequences (23.48-83.91%) between species. There was moderate similarity between H. huso and the reference H. huso samples. An unauthorized (a sample seized from poachers) sample was more closely related to A. stellatus. Partial coding region of AR gene was registered in NCBI database under Accession Number: KC172108. Five nucleotide changes were detected in this sequence, two of which resulted in changes in amino acid sequence. Also, a partial sequence consisted of two microsatellite regions of two and four nucleotide repeats. Three constructed dendrograms displayed the relationship among species according to certain genomic regions. These findings indicate a high level of diversity among and even within the same species. They also show that these three genes could be useful in species’ identification and characterization
Isolation of Shewanella putrefaciens from Goldfish (Carassius auratus auratus)
(2014) Altun, Soner; Büyükekiz, Ayşe Gül; Duman, Muhammed; Özyiğit, Musa Özgür; Karataş, Süheyla; Turgay, Emre
In the present study, the etiological agent that caused mortality in goldfish at an aquarium company located in Bursa in northwestern Turkey was identified. Diseased fish were lethargic, displaying a loss of appetite, ascites, and exophthalmia. Internal examination revealed that the kidney was surrounded by exudate and that the spleen and liver were pale. Microbiological examination showed that the kidney, spleen, and liver were infected by gramnegative, cytochrome oxidase, catalase, and H2S positive rod-shaped bacteria identified as Shewanella putrefaciens. Identification of the bacteria was confirmed by 16S rRNA gene sequencing. Histopathological examination of the kidney, spleen, and liver revealed necrosis in kidney tubules and the presence of hepatocytes and hemosiderin in melanomacrophages. According to the disk diffusion method, isolates were sensitive to enrofloxacin (5 µg), florfenicol (30 µg), gentamycin (120 µg), and sulfamehoxazole+ trimethoprim (25 µg).
Effects of the Amplitude and Frequency of Salinity Fluctuations on the Growth Performance of Juvenile Tongue Sole (Cynoglossus emilaevis)
(2014) Khairnar, Sachin Onkar; Tian, Xiangli; Fang, Ziheng; Dong, Shuanglin
The effects of amplitude (2, 4, 6, 8 ppt) and frequency (2, 4, 8 days) of salinity fluctuations on the growth, body composition, and energy budget in juvenile tongue sole (Cynoglossus semilaevis) were investigated for 64 days. Results showed that the frequency and amplitude, as well as the interaction between them, significantly affected the specific growth rate. The tongue sole had higher specific growth rates at the amplitudes of 4 and 6 ppt and frequencies of 4 and 8 days than tongue sole in other treatments or the unfluctuating control. In these treatments, food consumption, food conversion efficiency, and apparent digestion in terms of energy were also significantly higher than in the control. The growth rate of the juvenile tongue sole was a quadratic function of the salinity amplitude at various frequencies and was described by the equation G = β0 + β1(SA) + β2(SA)2, where G represents the specific growth rate on a 64-day basis, SA is salinity amplitude in ppt, β0 is the intercept on the G axis, and β1 and β2 are the regression coefficients, respectively. The optimal salinity amplitudes for the best growth at salinity fluctuation frequencies of 2, 4, and 8 days were estimated to be 3.54, 4.89, and 4.74 ppt, respectively, suggesting that commercial farmers can rear juvenile tongue sole in moderate salinity fluctuations to achieve better growth performance.
Effects of Antibacterial Peptide Extracted from Bacillus subtilis fmbJ on the Growth, Physiological Response and Disease Resistance of Megalobrama amblycephala
(2014) He, Yijin; Liu, Bo; Xie, Jun; Ge, Xianping; Xu, Pao; Lu, Ying; Lu, Fengxia; Lu, Zhaoxin
The effects of an antibacterial peptide obtained from Bacillus subtilis fmbJ on growth, serum lysozyme complements 3 and 4, total protein content, aspartate aminotransferase (AST), alanine aminotransferase (ALT), total antioxidative capacity, superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and disease resistance of Wuchang bream (Megalobrama amblycephala) were examined. Fish were randomly divided into five groups: a control group which was fed a basic diet, and four groups fed the basic diet supplemented with 0.1%, 0.2%, 0.4%, or 0.8% antibacterial peptide. At eight weeks, M. amblycephala fed the diet containing 0.2% antibacterial peptide had higher serum lysozyme activity, complement 3 and 4 contents, and SOD activity than the control fish, but lower serum MDA content and AST activity. Fish fed the 0.4% diet had higher weight gain rate, serum lysozyme activity, complement 4 content, total antioxidative capacity, and total protein than the control, and lower serum ALT activity. Feed conversion ratios of fish fed the 0.2% or 0.4% diets were lower than those of control fish. Artificial infection with Aeromonas hydrophila resulted in 93% cumulative mortality in the control group, and 61-84% in the groups fed the 0.2% or 0.4% diets. The present study suggests that feed supplementation with 0.2-0.4% antibacterial peptides can stimulate immunity, increase resistance to pathogenic infection, and promote growth in M. amblycephala.

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