bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Supplemented Dietary Curcumin on Growth and Non-Specific Immune Responses in Juvenile Wuchang Bream (Megalobrama amblycephala)
Authors: Xia Si-lei $Ge , Xie Jun , Miao Ling-hong , Ren Ming-chun , Zhou Qun-lan , Zhang Wu-xiao , Jiang Xiao-jun , Chen Ru-li , Pan Liang-kun
Published: February 2021

The present study was aimed at evaluating the effects of the feed additive curcumin on the growth and non-specific immune responses in juvenile Wuchang bream (Megalobrama amblycephala). Six experimental diets were formulated to contain graded curcumin levels (0, 15, 30, 60, 120 and 240 mg/kg of diet, respectively). After 60 days feeding trial, fish fed the 60 mg/kg curcumin diet had significantly higher weight gain rate (WGR) and specific growth rate (SGR), and significantly lower feed conversion ratio (FCR) than the control group. The number of leucocytes (WBC), interleukin-1 beta (IL-1β), tumor necrosis factor-α (TNF-α), alternative pathway of complement (ACH50), and respiratory burst activity increased with increasing dietary curcumin levels up to 60 mg/kg, and thereafter declined. Significantly lower alanine transaminase (ALT) and aspartate transaminase (AST) activities were observed in fish fed the 60 mg/kg curcumin diet compared to those in the control group. Fish fed with the diets containing 60 and 120 mg/kg curcumin had significantly higher TNF-α and ACH50 activities than those in the control, and the fish fed diets supplemented with 60 and 240 mg/kg curcumin had significantly higher IL-1β activities than those in the control. The results suggest that appropriate dietary curcumin supplementation (60 mg/kg curcumin of diet) significantly improved growth and non-specific immune responses in juvenile M. amblycephala.
Apparent Digestibility of Selected Feed Ingredients in Juvenile Turbot (Scophthalmus maxima L.)
Authors: Wei Yanjie , He Gen , Mai Kangsen , Xu Wei , Zhou Huihui , Mei Lin
Published: February 2021

In aquaculture, replacing dietary fishmeal with other protein sources is challenging. In order to select substitute sources, it is necessary to determine the apparent digestibility coefficients, many of which have not been well characterized for fish species. We investigated the apparent digestibility of eight protein sources fed to juvenile turbot (Scophthalmus maxima L.). These were Peruvian super red fishmeal (FM), peanut meal (PM), corn gluten meal (CGM), dehulled solvent extracted soybean meal (SBM), wheat gluten (WG), Australian beef meat and bone meal (MBM), spray-dried (pork) hemoglobin meal (SDHM) and American pet-food grade poultry byproduct meal (PBM). The apparent digestibility coefficients of dry matter (DM), crude protein (CP), gross energy (GE), and amino acids were analyzed. Results indicated that turbot utilized high-protein feedstuffs better than high-carbohydrate or high-fiber feedstuffs. This study provides valuable information on ingredient selection and evaluation of feed for turbot.
The Effects of Dietary Magnesium (Mg) Supplementation on Growth Performance of Adult Japanese Seabass (Lateolabrax japonicas)
Authors: Liang Mengqing , Wei Yuliang , Tan Feng , Zheng Keke , Xu ouguo
Published: February 2021

Japanese seabass, Lateolabrax japonicus (mean initial weight 204.5 g) were fed one of six casein-dextrin-based diets containing graded levels of magnesium (Mg) (184, 278, 487, 929, 1299, and 1737 mg/kg) for 10 weeks with the water-borne Mg concentration of 985 mg/L. Magnesium sulphate was used as the Mg source in the diets. The experiment was carried out in floating sea cages. Growth, survival rate, superoxide dismutase (SOD) activities, glutathione peroxidase (GPx), malondiadehyde (MDA) contents and tissue mineral contents were measured to investigate the effect of dietary magnesium in seabass. After 10 weeks, dietary magnesium supplementation did not improve the growth performance or feed efficiency of adult seabass. On the contrary, negative effects on growth performance, decreased glutathione peroxidase (GPx) and increased malondiadehyde (MDA) contents were observed in seabass fed Mg diets with 929, 1299 mg/kg and 1737 mg/kg, and feed efficiency (FE) exhibited a decreasing tendency with increasing Mg supplemental levels, which indicates the Mg requirement of seabass was met in fish fed the basal diet. Survival, hepatosomatic index, viscerosomatic index, condition factor, and Mg and Ca concentration in whole-body, vertebrae, and scales were not affected by dietary Mg supplementation (P<0.05).
Dietary Methionine Requirements of Pacific White Shrimp Litopenaeus vannamei, of Three Different Sizes
Authors: Lin Heizhao , Chen Yifang , Niu Jin , Zhou Chuanpeng , Huang Zhong , Du Qiang , Zhang Jiarun
Published: February 2021

Three feeding trials were conducted to determine the dietary methionine requirements for Litopenaeus vannamei of three different sizes, small (0.55±0.01g), medium (4.18±0.05g), and large (9.77±0.08g). Seven diets were formulated with seven different levels of methionine (0, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or 0.6%). The greatest weight gain (WG) and specific growth rate (SGR) of small and large shrimp were observed when dietary methionine levels were 0.8%, and 0.71%, respectively (P<0.05). The highest survival rate of small and large shrimp was observed when dietary methionine levels were 0.97%, and 1.07%, respectively (P<0.05). For small and medium shrimp, the optimal dietary methionine level for maximum weight gain estimated by quadratic regression analysis was 0.91% and 0.67% of dry diet, respectively. For large shrimp, the optimal dietary methionine requirement estimated by broken-line model based on weight gain was 0.66% of dry diet.
Application Frequency of Dietary Vibrio harveyi Lipopolysaccharide (LPS) on Growth and White Spot Syndrome Virus Resistance of Post Larvae Penaeus monodon
Authors: Genio Josette Emlen , Traifalgar Rex Ferdinand , Corre Valeriano Jr.
Published: February 2021

This study evaluated the effects of dietary Vibrio harveyi lipopolysaccharide (LPS) as an immunostimulant fed at different frequencies for improving growth performance, immune response, and disease resistance of post larvae Penaeus monodon against white spot syndrome virus (WSSV). In an 8 week feeding trial, shrimp were fed a treatment diet containing Vibrio harveyi LPS at a predetermined dose of 50 mg/kg diet daily or every 2, 5, and 7 days. A basal diet was given to the treatment groups when the shrimp were not fed the dietary immunostimulant. Results showed 90-96% survival of the test animals, and weight gain (WG) and specific growth rate (SGR) were significantly enhanced in shrimp fed LPS every 2 days. No significant differences were observed in the feed conversion ratio (FCR) of any of the test groups. Following WSSV challenge, the groups receiving LPS-supplemented diet exhibited increased disease resistance compared to the control group. Shrimp fed with LPS every 2 days exhibited significantly higher survival rate (53%) than the other treatments. The same group consistently showed significantly higher values in all immune indices measured including total hemocyte count (THC), phenoloxidase (PO) activity, and respiratory burst activity (RBA). This study suggests that dietary administration of Vibrio harveyi LPS at 50 mg/kg concentration fed every 2 days is optimum to enhance growth, immune response, and protection against WSSV in post larval P. monodon.
Lipid Requirements in Growing Japanese Seabass (Lateolabrax japonicus) of Two Different Sizes
Authors: Xu Houguo , Dou Bingshuai , Zheng Keke , Liang Mengqing
Published: February 2021

The optimal lipid requirements in Japanese seabass of two different sizes (initial body weight, 34.26±0.37 g, and 343.3±10.0 g) were tested using the same experimental diets in two feeding trials (trial I and trial II). Five experimental diets were formulated to obtain graded dietary lipid levels: 0.6%, 3.9%, 7.3%, 11.7%, and 15.8%. Each diet was randomly assigned to triplicate groups of fish. Both feed trials lasted 10 weeks. The results in both feeding trials showed that specific growth rate significantly increased by increasing dietary lipid levels from 0.6% to 7.3%, and declined thereafter. Based on the specific growth rate, the optimum dietary lipid requirement of the small and large Japanese seabass was 7.4% and 9.9% respectively. The increasing dietary lipid levels significantly increased the fish body protein concentration, but only in feeding trial II. In both feeding trials, the lipid contents in whole fish body and liver significantly increased with increasing dietary lipid levels, but the small fish showed much lower lipid content than the large fish. The serum triglyceride concentrations in the small fish were higher than those in the large fish. High levels of dietary lipid (3.9% and 7.3%) reduced the serum cholesterol concentrations in the small fish, which was much lower than those in the large fish. These results suggested that the lipid requirements, as well as the body composition and lipid deposition differed according to the size of growing Japanese seabass. The results are important for feed formulation for aquaculture of different sized Japanese seabass throughout their production cycle.
Effect of Replacing Canola Meal for Fish Meal on the Growth, Digestive Enzyme Activity, and Amino Acids, of Ovate Pompano, Trachinotus ovatus
Authors: Kou Hongyan , Xu Shuying , Wang An-Li
Published: February 2021

Ovate Pompano (Trachinotus ovatus) is one of the most highly valued aquaculture species due to its commercial value, rapid growth, high quality flesh, and suitability for cage culture. Ovate Pompano were fed diets containing graded levels of canola meal to replace the fish meal. Six diets containing 45% crude protein and 12% crude lipid were fed to the fish during the 8-week feeding trial. Weight gain of the fish was negatively related to canola meal ratio in the diets. Protein efficiency and feed conversion ratio were inversely related to the canola meal inclusion in the diets. The crude lipid of the fish was positively related to the dietary canola meal, while an inverse trend was found in the crude protein of the fish. Protease activity and amylase activity showed a similar trend to the crude protein, while the lipase activity showed an inverse trend. No significant differences were observed in the moisture, ash, or fillet yield of the fish among dietary treatments. The “delicious amino acid”i.e. those eliciting Umami flavor (UEAA), e.g. glutamic acid and others, essential amino acid, and total amino acid content of the fish were inversely related to the canola meal ratio in the diets. The results of the experiment indicated that canola meal can replace 18.17 % fish meal without affecting growth. Higher substitution levels of canola meal produced adverse influences on growth, digestive enzyme activity, and amino acid content of Ovate pompano.
Broad Spectrum Anti-Bacterial Activity of a Recombinant Phosphatase-Like Protein (rPLP), Isolated from the Shrimp Penaeus monodon
Authors: Banerjee Debashis , Maiti Biswajit , Girisha S.K , Venugopal M.N , Karunasagar Indrani
Published: February 2021

Antimicrobial peptides play a significant role in the innate immune response of crustaceans. The gene coding for a phosphatase-like protein (PLP) from the black tiger shrimp, Penaeus monodon was cloned using pQE-30-UA expression vector and expressed in Escherichia coli M15 host cells. The recombinant protein purified by nickel-nitrilotriacetic acid affinity chromatography, gave a single distinct band of approximately 25 kDa by 15% sodium dodecyl sulfate polyacrylamide gel electrophoresis. The anti-bacterial activity of the recombinant phosphatase-like protein (rPLP) was characterized in vitro. Solid phase agar based assay revealed its inhibitory effect against several gram positive and gram negative bacteria. The minimal inhibitory concentration of the rPLP against Vibrio harveyi, by micro dilution method, was 1 μg/ml. This protein offers promise for use in hatcheries to control luminous vibriosis.
Growth Performance and Apparent Digestibility Coefficients of Selected Feed Ingredients for Red Swamp Crayfish Procambarus clarkia.
Authors: Wan Jin-juan , Xia Ai-jun , Shen Mei-fang , Ding Zheng-feng , Xue Hui , Huang Hong-bing , Geng Xue-bing , Hao Chen , Wu Pei-qi , Liu Hong-yan
Published: February 2021

In this study, the growth performance and apparent digestibility coefficients (ADCs) of dry matter (DM), crude protein (CP), crude lipid (EE), gross energy (GE), phosphorus (P), essential amino acids (EAA), and nonessential amino acids (NEAA) for fish meal (local) (FM), soybean meal (SBM), rapeseed meal (RM), cottonseed meal (CM), peanut meal (PM), and extruded soybean (ESB) were determined for red swamp crayfish Procambarus clarkia, (weight 5.43 ± 0.21 g), using a reference diet (RF) and test diets (70% RF diet plus 30% of tested ingredient) containing 0.1% Yttrium oxide as an inert marker. The results showed that there was no significant difference in SGR, FCR, and survival among all groups (P>0.05). Apparent digestibility of DM, CP, EE, P, and GE of six feed ingredients ranged from 62.8 to 71.4%, 71.2 to 90.3%, 44.2 to 92.1%, 70.1 to 83.9% and 40.3 to 63.5 %, respectively. From the data for the six feed ingredients, SBM was found to contain the highest ADCs levels in DM (71.4%) and GE (83.9%). FM recorded the highest ADC in EE (92.1%), while PM and CM had the highest ADCs of CP (90.3%), and P (63.5%), respectively. The lowest apparent digestibility of DM, CP, and GE was found in RM, the lowest apparent digestibility of EE was found in ESB, and FM had the lowest ADC of amino acids. Based on the current findings, SBM, CM, and PM could be considered potential substitutes for FM in diets for red swamp crayfish.
Use of Distillers Dried Grain as a Cost Effective Ingredient in the Diet of Juvenile Olive Flounder (Paralichthys olivaceus)
Authors: Rahman Md Mostafizur , Cho Jin , Lee Sang-Min
Published: February 2021

This study assessed the effects of the dietary inclusion of distillers dried grain (DDG) on growth performance, feed utilization, body composition, and antioxidant activity in juvenile olive flounder (Paralichthys olivaceus). Five diets (DDG0, DDG1, DDG2, DDG3, and CF) were formulated to contain 0% (DDG0), 20% DDG (DDG1) replacing wheat flour only, and 20% DDG (DDG2) and 28% DDG (DDG3) partially replacing both fishmeal and wheat flour. Experimental diets were also compared with a commercial feed (CF) diet. Three replicate groups of fish average weight 16.0±0.04 g were fed each of the diets to apparent satiation twice a day for 7 weeks. Weight gain of fish fed the DDG1 and DDG2 diets was the same as fish fed DDG0 diet, but there was less weight gain in fish fed the DDG3 diet than those fed the DDG0 and CF diets. Feed efficiency, daily feed intake, daily protein intake, and protein efficiency ratio were not affected by dietary DDG and CF diets (P>0.05). Whole body content (WBC) of crude lipid in fish fed the DDG1 and CF diets was the same as fish fed DDG0 diet. WBC was higher in fish fed the DDG2 and DDG3 diets than in fish fed the DDG0 diet. Amino acid composition of whole body was not affected by dietary DDG and CF diets (P>0.05). Plasma content of total protein, cholesterol, and triglyceride, tended to decrease with dietary DDG level, and was lower in fish fed the DDG3 diet than fish fed the DDG0 and CF diets. DPPH, hydroxyl, alkyl and superoxide radical scavenging activities in the plasma of fish were not affected by dietary DDG and CF diet (P>0.05). The results suggest that up to 20% DDG in the diet could be used to replace plant components such as wheat flour and corn gluten meal, without negatively affecting growth performance of juvenile olive flounder.
Effect of Biogut on Growth Performance of Cyprinus carpio (Linn.) Fingerlings.
Authors: Doddamani Pradeep L. , Basavaraja B. T. Naveen Kumar , Behera B. K. , Tripathy M.K. , Sarkar Soma D. , Choudhury Sampurna R. , Sahoo A. K.
Published: February 2021

In this study we evaluated the effect of three levels of Biogut (a probiotic) on growth performance of common carp fingerlings. Biogut was incorporated into a formulated diet (protein level: 35%) at 0.5, 1.0 and 1.5% of the diet and designated as T1, T2 and T3 and T0, the fourth (control) diet, without biogut. The diets were fed to common carp fingerlings, stocked at 10/tank, with three replicates, for 60 days. Results indicated that the common carp fingerlings fed with the diets containing biogut exhibited increased growth compared to those fed the control diet. The survival rate was 100% in all the groups. The average weight and length of common carp was maximal in the 0.5% biogut treated group. Specific growth rate, protein efficiency ratio, RNA/DNA ratio and protease activity were also highest in the group fed on 0.5% biogut. The results demonstrate that 0.5% biogut supplementation in the diet of common carp fingerlings produces positive effects.
Effects of dietary xylan on growth performance, digestive enzyme activity and intestinal morphology of juvenile turbot (Scophthalmus maximus L.)
Authors: Hu Haibin , Mai Kangsen , Zhang Yanjiao , Ai Qinghui , Xu Wei , Zhang Wenbing , Li Yanxian , Liu Jintao
Published: February 2021

A 12-week feeding trial was conducted to evaluate the effects of dietary xylan on growth performance, digestive enzyme activity, and intestinal morphology of juvenile turbot (Scophthalmus maximus L.) with a mean initial body weight of 4.63 ± 0.01 g. Five isonitrogenous and isolipidic diets were formulated to contain 0%, 0.625%, 1.25%, 2.5% and 5% xylan, respectively. The dietary supplementation of 5% xylan significantly decreased (P<0.05) fish feed intake, growth performance and feed utilization, but these parameters were significantly improved (P<0.05) by 1.25% dietary xylan supplement. Similar trends were observed in whole-body protein and lipid contents of experimental fish. The activity of intestinal caseinolytic, trypsin, and intestinal amylase were inversely related to the supplemented dietary xylan (P<0.05). The integrity of the distal intestine was impaired and the length of intestinal epithelium (lIE) significantly declined (P<0.05) when 5% xylan was added to the diet. Results of the present study suggest that dietary xylan affected the growth performance and feed utilization of juvenile turbot, with beneficial effects at an intermediate supplemental level of 1.25% but with adverse effects at higher supplemental levels (5%).
Effects of Soya Saponins on Feed Intake, Growth Performance, and Cholesterol Metabolism in Juvenile Turbot (Scophthalmus maximus L)
Authors: Yun Biao , Ai Qinghui , Qian Xueqiao , Mai Kangsen
Published: February 2021

An 8-week feeding trial was conducted to investigate the effects of soya saponins on feed intake, growth performance, and cholesterol metabolism in juvenile turbot (Scophthalmus maximus L). A control diet and two experimental diets were prepared with the supplementation of soya saponins, concentrations being as follows: 0.0% (Diet 1, Control), 0.25% (Diet 2) and 0.5% (Diet 3), respectively. The results showed that 0.25% of dietary soya saponins produced comparable growth performance with the control diet. However, the growth performance of fish fed the diet with 0.5% soya saponins was significantly lower. The selected parameters measured in plasma, liver, and feces of each group were not significantly different. These results suggested that 0.25% dietary soya saponins did not produce negative effects, but but but but 0. 5% of dietary soya saponins significantly reduced fish growth. Dietary soya saponin supplementation to FM-based diet did not significantly affect cholesterol metabolism.
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
Authors: Yigi Nalan Ozgur , CiHangir Esra , Metin Selin , Koca Seval Bahadir
Published: February 2021

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%.
Use of Lactic Acid Bacteria from Nile tilapia Oreochromis niloticus as Probiotics for Sustainable Production and Improvement in Fish Welfare
Authors: L.C Nwanna , Ajani E. K. , Bamidele S. F.
Published: February 2021

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.
Effect of Feeding Frequency on Growth Rate, Body Composition and Gastric Evacuation of Juvenile GIFT Strain of Nile Tilapia (Oreochromis niloticus)
Authors: Bin Chen , Qi Peng , Bin Wu , Bo Luo , Wen Liang $Jian
Published: February 2021

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.
Isolation of Shewanella putrefaciens from Goldfish (Carassius auratus auratus)
Authors: Altun Soner , Büyükekiz Ayşe Gül , Duman Muhammed , Özyiğit Musa Özgür , Karataş Süheyla , Turgay Emre
Published: February 2021

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)
Authors: Khairnar Sachin Onkar , Tian Xiangli , Fang Ziheng , Dong Shuanglin
Published: February 2021

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.
Evaluation of Berberine’s Algicidal Effects on Toxic Microcystis aeruginosa Growth using a Double Fluorescein Staining Method
Authors: Zhang Shulin , Zhang Mingming , Dai Wei , Bi Xiangdong , Yang Pan , Zhang Dajuan
Published: February 2021

An accurate and convenient method for determining Microcystis cell viability is necessary to control blooms in small aquaculture water bodies. The fluorescein diacetate-propidium iodide (FDA-PI) staining method was developed to determine the viability of toxic Microcystis aeruginosa (FACHB905). Live M. aeruginosa 905 cells, stained with FDA, emitted bright green fluorescence after excitation at 470 nm. Dead cells, stained with PI, produced bright red fluorescence after excitation at 540 nm. Berberine inhibited M. aeruginosas 905 growth and the inhibition rate determined by FDA-PI fluorescein staining and counting on a dark field was much higher than when determined by counting on a bright field because some berberine-killed cells were misidentified as live cells. Thus, less berberine is needed to control Microcystis bloom when the accurate and reliable FDA-PI fluorescein staining method is used to judge the viability of the algae cells.
Effects of Dietary Lipid and Carbohydrate and Their Interaction on Growth Performance and Body Composition of Juvenile Blunt Snout bream, Megalobrama amblycephala
Authors: Li Xiang-Fei , Lu Kang-Le , Liu Wen-Bin , Jiang Guang-Zhen , Xu Wei-Na
Published: February 2021

The effects of dietary lipid and carbohydrate, and their interaction, on growth performance and body composition of juvenileblunt snout bream Megalobrama amblycephala were investigated. Fish were fed one of eight isonitrogenous (32% crude protein) diets containing 4% or 7% lipids and 25%, 30%, 35%, or 40% carbohydrate for nine weeks. Weight gain, feed conversion ratio, protein efficiency ratio, and nitrogen and energy retention improved significantly as the dietary lipid level increased, while there were no significant differences in these parameters within the tested range of carbohydrate levels. The interaction between the lipid and carbohydrate levels had positive effects on weight gain, feed conversion ratio, and protein efficiency ratio when fish were fed increased carbohydrates and 7% lipid. The intraperitoneal fat ratio and liver lipid content were significantly affected by the dietary carbohydrate level and reached maximum values in fish fed 40% and 30% carbohydrates, respectively. Further, the dietary lipid and carbohydrate levels significantly affected body moisture and lipid content while there were no significant differences in body protein, ash, energy, or muscle and liver glycogen contents. Results indicate that the optimal dietary carbohydrate content for juvenile M. amblycephala is approximately 30% when dietary lipid is 4%. However, juvenile M. amblycephala can efficiently utilize 40% dietary carbohydrate with a dietary lipid content of 7%.
Conservation genetics of tilapias: Seeking to define appropriate units for management
Authors: Hallerman Eric , Hilsdorf Alexandre Wagner Silva
Published: February 2021

Tilapias comprise 112 species and subspecies of cichlid fishes of the genera Oreochromis, Sarotherodon, and Tilapia. Because of the importance of tilapias to aquatic ecosystem structure and function, fisheries, and aquaculture, it is critically important to conserve wild genetic resources. Of the 112 recognized tilapia taxa, 41 are regarded as imperiled. In order to manage adaptively important genetic variation in tilapias, we need to recognize and define biologically appropriate units of conservation. An evolutionary significant unit (ESU) can be defined as a population or group of populations that merits priority for conservation and separate management because of high genetic and ecological distinctiveness from other such units. Management units (MUs) are defined as populations that are demographically independent of one another; that is, their population dynamics depend mostly on local birth and death rates, and not on genetically effective migration. Identification of MUs – similar to “stocks” widely referred to in fisheries management – is useful for short-term management, such as managing habitat, delineating fishing areas, setting harvest rates, and monitoring population status. Against this background, the goal of our review and synthesis was to summarize knowledge and recommend critical work yet to be done regarding conservation of tilapias, approaching this task in a species-by-species manner. With the exceptions of Oreochromis niloticus, O. mossambicus, and Sarotherodon melanotheron, the body of existing work regarding genetic and adaptive differentiation of populations of tilapias is insufficient to inform identification of evolutionary significant units, a knowledge gap that should be addressed by targeted research. We note that competition and interspecific hybridization caused by introductions of tilapias for aquaculture purposes jeopardizes the genetic resources of certain native tilapia species. We hope that our review and synthesis spark critical discussion of tilapia conservation within the tilapia aquaculture, management, and conservation communities.
The Development of a Small-scale Laboratory System to Study Cryptocaryon irritans Infection in Seawater-adapted Guppies, Poecilia reticulata
Authors: Fridman S. , Zilberg D.
Published: February 2021

The protozoan parasite Cryptocaryon irritans is responsible for significant economic losses of commercially farmed marine fishes. In this study we report, for the first time, C. irritans infection in the seawater-adapted guppy Poecilia reticulata. We describe a simple method for experimental propagation and maintenance of the infection in a laboratory, without apparent loss of infectivity, for15 months. Fish were gradually adapted to increasing concentrations of artificial seawater by successive transfer to incremental steps of 10 ppt every 2 days and then transferred to disease propagation aquaria (salinity 30 ± 2 ppt) where the infection was maintained. Between 2- 3 fish were held at any one time in each aquaria, each fish being replaced once it succumbed to the infection and died. Gross observations of heavily infected fish revealed a uniform distribution of trophonts visible on the skin and fins as white surface lesions or ‘spots’ after 4-5 days. Death of the host usually occurred after 7-8 days. Heavily infected fish were fixed and processed using routine histological techniques and histological examination revealed infective trophonts, round or pyriform in shape, invading the fish epithelium as well as larger, feeding trophonts located beneath the epithelium. A thickening of the epithelial layers and a proliferation of mucous secreting cells was evident around embedded parasites.
Effects of Dietary Squid Soluble Fractions on Growth Performance and Feed Utilization in Juvenile Snakehead(Ophiocephalus argus) Fed Practical Diets
Authors: Ai Qinghui , Xue Hua , Qian Xueqiao
Published: February 2021

An 8-week growth trial was conducted to investigate the effects of dietary squid soluble fractions (SSF) supplementation on growth performance and feed utilization of juvenile snakehead (Ophiocephalus argus). A fish meal diet (diet 1) with 36% fish meal (FM) was formulated. This diet was used as a control. The second diet (diet 2) was formulated by replacing 22% of the fish meal protein with poultry by-product meal based on amino acid profile of whole body of this fish. The other three diets were supplemented with 0.4% (diet 3), 0.8% (diet 4) and 1.2% (diet 5) SSF, respectively. Diets 1(control) 2, 3, 4, and 5 were isonitrogenous and isolipidic. No significant differences were observed in survival, feed intake (FI), weight gain rate (WGR), feed efficiency rate (FER) and protein productive value (PPV) between fish fed diets 1 and 2 (P>0.05). Furthermore, compared with fish fed the diet without SSF (diet 2), fish fed diets with 0.8 and 1.2% SSF (diet 4 and 5) demonstrated significantly enhanced WGR, FER, and PPV. These results suggest that 0.8% of dietary SSF is optimal for juvenile snakehead growth enhancement.
Use of Natural Zeolite for Ammonia Removal during Simulated Transport of Live Juvenile Sea Bass (Dicentrarchus labrax)
Authors: Kanyılmaz Mahir , Koçer Mehmet Ali T. , Sevgili Hüseyin , Pak Faruk , Aydın İsa
Published: February 2021

This study was conducted to determine the effects of zeolites on total ammonia nitrogen (TAN) removal during a 24-hour-sea bass transport. Five experimental treatments (0 (control), 10, 20, 30 and 40 g/l zeolite) with 3 replications were applied in 14 l plastic tanks. 90 sea bass (total weight 175.07 ± 0.49 g) were stocked in each tank. The zeolites were placed in mesh bags and renewed 8 and 16 hours (h) after the commencement of transfer. TAN contents of tank waters were measured after 8, 16 and 24 h. The results revealed that at the 8th h, 20, 30 and 40 g/l zeolite doses were significantly effective compared with the control. At the 16th and 24th h the lowest zeolite level (10 g/l) was also effective in TAN removal. In general highest TAN removal was achieved with 40 g/l treatment with efficiencies of 18.33%, 34.08% and 20.96% at the 8th, 16th and 24th h respectively. Overall, the results suggest that the use of zeolite in sea bass transportation could bring remarkable benefits and thereby increase fish transportation density and welfare.
Effect of Replacing Live Food with Formulated Feed on Reproductive Performance of Freshwater Angelfish, Pterophyllum scalare (Shcultze, 1823)
Authors: Shelar G.S. , Singh H. , Shirdhankar M.M. , Shelar P.
Published: February 2021

The combined effect of live food (LF) and formulated feed (FF) on reproductive performance of Pterophyllum scalare was studied. Mosquito larvae were used as live food in addition to formulated feed which contained 50% protein and 12% lipid. The experiment was arranged as a completely randomized design (CRD) with six replicates for each treatment: P. scalare were fed with formulated feed and/or live food: T1 (100% FF), T2 (75% FF and 25% LF), T3 (50% FF and 50% LF), T4 (25% FF and 75% LF) and T5 (100% LF). Relative fecundity, egg and oil globule diameter was significantly higher (P < 0.05) in T4 and T5 diets whereas inter spawning interval was lower in T3, T4, and T5 diets. Similarly hatching percentages were significantly higher with diets T3, T4, and T5. There were no significant differences observed between treatments on relative hatchling number, hatchling length, and weight. No significant difference was observed for egg and whole body composition of P. scalare fed with different diets. However there was a significant difference between treatments on fatty acid profile. It was concluded that live food can be replaced by up to 25-50% formulated feed without compromising reproductive performance of P. scalare
Synergistic Effects of Two Probiotic Bacteria on Growth, Biochemical, and Immunological Responses of Litopenaeus vannamei (Boone, 1931)
Authors: Kumar A. , Suresh Babu P. P. , Roy S. D , Razvi S. S. H , Charan R.
Published: February 2021

The beneficial effects of two probiotic bacteria, Bacillus licheniformis and Bacillus megaterium, on growth, biochemical, and immunological responses of Litopenaeus vannamei (Boone, 1931) were evaluated both individually and in combination. A 60 day experimental trial was conducted on 1200 post larvae (PL) of Litopenaeus vannamei divided into four experimental groups, with three replicates of each treatment, and 100 PL in each replicate. The shrimp were fed a commercial diet (32% protein) supplemented with different probiotics. The first treatment included only B. licheniformis @ ~ 1x 108 cfu/kg diet (T1), the second consisted of a combination of ~ 0.5 x 108 cfu/kg of B. licheniformis mixed with a similar concentration of B. megaterium (T2), and the third had only B. megaterium @ ~1x 108 cfu/kg diet (T3). The control diet (C) had neither of the probiotic bacteria. Growth performance, biochemical, and immunological parameters of experimental shrimp were measured at 20 day intervals. Probiotic fed shrimp showed significantly higher growth, biochemical, and immunological response than the control. Among the probiotic treatments the mixture of B. licheniformis and B. megaterium (T2) performed better than the individual probiotics alone, indicating the synergistic effect of these two functionally different probiotics
Isolation and Characterization of Potential Probiotic Bacteria from Rainbow Trout Oncorhynchus mykiss, (Walbaum) Rearing Units Against Bacterial Pathogens
Authors: Didinen Behire Işıl , Metin Secil , Onuk Ertan Emek , Takmaz Hayriye , Ersoy Ahmet Tahir
Published: February 2021

Bacteria were studied for potential probiotic activity against vibriosis, yersiniosis and lactococcosis in rainbow trout. A total of 79 bacterial strains were isolated from rainbow trout rearing water, and screened for antagonistic activity against Vibrio anguillarum, Yersinia ruckeri and Lactococcus garvieae using a well-diffusion agar assay. Vibrio spp. showed inhibitory activity against V. anguilarum and L. garvieae, while Aeromonas spp. displayed antagonistic activity against L. garvieae. Antagonistic L. garvieae strains displayed inhibitory activity against all pathogens. Antagonistic strains were characterized for enzymatic activity (protease, lipase) and hydrophobicity. Vibrio sp. A12, and Aeromonas sp. A5, G1, were found to have enzymatic properties and hydrophobicity. L. garvieae strains showed weak hydrophobicity and did not display enzymatic activity. Phenotypic characteristics of antagonistic strains were determined by conventional API 20NE and API STREP rapid identification systems. Antagonistic L. garvieae strains were confirmed as L. garvieae by PCR using species-specific primers. Candidate probiotic strains were tested for pathogenicity in rainbow trout by intraperitoneal injection. Following a challenge, L. garvieae strains caused mortality and were eliminated from further study. As a result, Aeromonas spp. and Vibrio spp. were identified as probiotic candidates with the potential to control vibriosis and lactococcosis.
A Study on Probiotic Bacteria Isolated from Common Dentex (Dentex dentex) Larvae and their antagonistic effect on Photobacterium damselae subsp. Damselae
Authors: Akayli T. , Ürkü Ç.
Published: February 2021

Bacterial species that can be considered as probiotic are gradually gaining attention and contributing to the success of aquaculture. The aim of this study was to determine the indigenous dominant probiotic bacterial species of common dentex (Dentex dentex) larvae and their effectivness against the putative fish pathogen Photobacterium damselae subsp. damselae at different feeding stages. In 2009-2010 samples of larvae and tank water were collected at 5 different occasions. After inoculations of samples, bacterial isolates were identified with standard biochemical methods. The antagonistic effects of the identified probiotic bacteria against P. damselae subsp. damselae isolated from different mariculture fishes were determined by using disc diffusion method. Bacillus cereus, B. macquariensis, and other Bacillus sp., Micrococcus luteus, Flavobacterium flevense and Flavobacterium sp. were identified as candidate probiotic species and their antagonistic effect against different P. damselae isolates was identified. The results of this study showed that B. cereus and M. luteus are more effective against Photobacterium damselae subsp. damselae. As a result, the identification of the candidate probiotic species and the widespread use of probiotics may improve the success of common dentex culture in the future.
Cyclopamine Induced Expression of Immune-related Genes in Rainbow trout (Oncorhynchus mykiss) Head Kidney Leukocytes
Authors: Sõnmev A.Y. , Özdemir R.C. , Bilen S. , zdemit Y.K.
Published: February 2021

This study investigated the effect of cyclopamine, a hedgehog signaling inhibitor, on immune-related gene expression in rainbow trout head kidney leukocytes in vitro. At 1h sampling time COX 2, IFN-2, TNF-α, C3, MHC-II, Il-1β, IL-12, IL-10, and IL-6 increased significantly in groups exposed to cyclopamine at 30 μg/ml. However, in groups exposed to 10 and 20 μg/ml cyclopamine, the expression of these genes decreased significantly. At 4h sampling time, levels of COX-2, IFN-1, IFN-2, TNF-α, TGF-β, IgT, and MHC-II in groups exposed to 20 μg/ml cyclopamine increased. At 8h sampling time, COX2, IFN-Reg, and TNF-α expression in groups exposed to 10 and 30 μg/ml cyclopamine increased significantly compared to those in the controls. Conversely the expression decreased significantly for almost all other genes. At 12h sampling time, almost all genes increased significantly in groups exposed to 10 μg/ml cyclopamine compared to those in the controls. Notably, after 24h, the gene expression in all groups significantly decreased compared to the controls. Our results suggest that the activation of cyclopamine can be a useful tool for the examination of immune-related gene expression in the rainbow trout.
Pharmacokinetics and Tissue Residence of Various Doses of Levamisole in Crucian Carp at Different Water Temperatures
Authors: Li G. , Liu Y. , Gao C. , Dai X. , Yang B. , Liu T. , Zu X.
Published: February 2021

The pharmacokinetics of levamisole in crucian carp, including the absorption, distribution, and clearance rates in different tissues, were studied at different temperatures and doses for the theoretical basis of proper usage and withdrawal time. The fish were divided into three groups denoted A, B and C. The A and B groups were treated once at a dosage of 5 mg/kg levamisole, at 19 ± 1°C and 26 ± 1°C water temperature, respectively. The C group was treated at a dosage of 20 mg/kg levamisole at 19 ± 1°C water temperature. Then plasma, muscle, hepatopancreas, and kidney tissues samples were collected and pretreated, then measured using an ultra performance liquid chromatography-ultraviolet method. Plasma data were analyzed using DAS 3.0 pharmacokinetics software. Total area under the curve (AUC0-t) and elimination half-life (t1/2z) had a negative correlation with water temperature, and a positive correlation with dosage. Apparent volume of distribution (Vz) and total clearance rate (CLz) was positively correlated with temperature, and

a negatively correlated with dosage. Levamisole was absorbed quickly to reach its peak concentration. The drug concentration and residence time in hepatopancreal and kidney were considerably higher and longer respectively than in the muscle and plasma suggesting that the hepatopancreas and kidney may be important metabolic organs for levamisole.
Efficiency of Dietary β-glucan Supplementation on Growth, Body Composition, Feed, and Nutrient Utilization in Juveniles of Pompano Fish (Trachinotus ovatus, Linnaeus, 1758)
Authors: Hoang D.H. , Lam H.S. , Nguyen C. V.
Published: February 2021

An 8-week experiment was conducted to examine the effect of increasing levels of dietary β-glucan on the growth performance, feed utilization, and body composition of juvenile pompano (Trachinotus ovatus). Pompano (mean initial weight, 6.45 g) were fed five diets containing five levels of β-glucan (D1 (control): 0%; D2: 0.05%; D3: 0.10%; D4: 0.20%; and D5: 0.40%. Results showed that growth performance, body composition, efficacy of feed and nutrient utilization were significantly affected by dietary β-glucan levels. After 8-weeks of feeding, weight gain, daily weight gain, specific growth rate, final body weight, coefficient of variation were highest in pompano fed 0.05% and 0.10% β-glucan in the diet (P ≤ 0.034), while growth of fish fed 0.2% and 0.4% β-glucan did not significantly differ compared to fish fed the control diet (P ≥ 0.170). Survival rate of juvenile pompano was not influenced by β-glucan supplement in the diet (P ≥ 0.383). In addition, feed utilization daily feed intake, feed conversion ratio, and feed conversion efficiency were significantly lower in fish fed diets supplemented with 0.01–0.10% β-glucan (P ≤ 0.027). In contrast, feeds supplemented with 0.2 to 0.4% β-glucan did not influence the feed utilization of pompano after 56 days of diet feeding (P ≥ 0.051). Protein was significantly higher in the flesh of pompano fed 0.05% to 0.10% β-glucan (P ≤ 0.001), while lipid content in fish decreased significantly with graded levels of β-glucan in the diet (P ≤ 0.044). After 56 days, protein efficiency ratio (PER), protein productive value (PPV), and fractional rates of protein growth (Kg), were significantly higher in fish fed diets supplemented with 0.05 -0.10% β-glucan (P ≤ 0.025).