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Summary The combined effects of temperature and salinity on the yolk utilization of sac fry in Nile tilapia (Oreochromis niloticus) were investigated using central composite experimental design and response surface approach. Based on the preliminary trials, temperature was determined to range from 22 to 34°C, and salinity ranging from 2 ppt to 10 ppt. The utilization was mensurated in terms of yolk sac volume. Results showed that the linear effects of temperature and salinity on the yolk utilization was significant (P

RNA-Seq technology has been widely applied to transcriptomics, genomics and functional gene study. Here, we performed de novo transcriptome sequencing to produce 23,842,172 clean reads representing a total of 4,815,798,404 (4.8 Gb) nucleotides from comprehensive transcript dataset for testis of Coilia nasus. Over 20 million Illumina reads were assembled into 194,636 unigenes, and 42,642 annotated genes were predicted by Blastx and ESTScan, respectively. Applying Blast analysis and functional annotation (e.g., GO, COG, SwissProt and KEGG) using the assembled gene models from catalogs of other species, we have sampled an extensive and diverse expressed gene catalog for C. nasus representing a large proportion of the genes involved in the onset of spermatogenesis. The results will provide a general clue to the potential spermatogenesis molecular mechanisms for this species.

Coilia ectenes is an important teleost species in the Yangtze River and a model organism that can be used to study the protection of fish resources. In this report, we performed de novo transcriptome sequencing of ten cDNA libraries from the brain, gill, heart, intestine, kidney, liver, muscle, stomach, ovary, and testis tissues. A total of 352 million raw reads of 100 base pairs were generated, and 130,113 transcripts, corresponding to 65,350 non-redundant transcripts, with a mean length of 1520 bp, were assembled. BLASTx-based gene annotation (E-value

Morphological characteristics and elemental fingerprints were compared in Chinese mitten crabs(Eri-ocheir sinensis) from three lakes(Taihu Lake,Shijiu Lake and Gucheng Lake) in Jiangsu Province.Truss network analysis using 16 length measurements suggested that crabs from the three lakes could not be reliably character-ized based on morphological characteristics.The accuracy rates yielded by discriminant analysis were 70% for crabs from Taihu Lake,90% for those from Shijiu Lake,and 80% for those from Gucheng Lake.An Agilent 7500ce ICP-MS was used to measure the concentrations of 21 chemical elements(Na,K,Ca,Fe,Mg,Sr,Ag,Al,As,Ba,Cd,Co,Cr,Cu,Mn,Mo,Ni,Pb,Se,Tl and Zn) in the third pereiopod of the crabs from the three lakes.The concentrations of Cr,Co,As,Se,Cd,Pb,Tl,Ag,Mo,and Ni were below the detection limit.However,in contrast to the morphological analysis,the origin of the crabs from the three lakes could be consistently identified from their elemental fingerprints.The corresponding accuracy rates yielded by discriminant analysis were 100% for crabs from Taihu Lake,80% for those from Shijiu Lake,and 100% for those from Gucheng Lake.We conclude that the approach of using environmentally determined elemental fingerprints in the third pereiopod of the crabs is a potentially valid method for identifying the geographical origin of Chinese mitten crabs.

Physiological responses and HSP70 mRNA expression to short-term crowding were tested in juveniles genetically improved farmed tilapia (Oreochromis niloticus) (70.43 ± 4.43 g). Fish were kept at control group (5 g L−1) and stress groups (low density 10 g L−1, medium density 40 g L−1 and high density 70 and 100 g L−1) for 48 h. Each density was tested in triplicates. The effects of a short-term exposure on the physiological responses of fish were determined before stress (0 h) and at 6, 12, 24 or 48 h post-crowding. There was a significant increase in serum cortisol, total protein, lysozyme and aspartate aminotransferase (AST) activities in all stressed groups at 24 h post-crowding (P

We attempted to determine the combining ability and heterosis of body weight by performing 3 × 3 complete diallel crosses derived by crossing three common carps (Cyprinus carpio var. jian, Cyprinus carpio haematopterus Temminck et Schlegel and Cyprinus carpio haematopterus). In total, 1650 fish were tagged when they were 1.5 months of age. After five months, Jian carp (♂) × Huanghe carp (♀) attained greater weight than pure and other hybrids. By crossing with Jian, Huanghe and Heilongjiang carps have improved body weight compared to their purebred. Significant principal components (PCs) were generated from growth performance data and their statistical loadings. The first principal component had the highest Eigen value of 2.81 and accounted for 70.31% of the variability in the data set. Two crosses, Jian carp (♂) × Huanghe carp (♀) and Huanghe carp (♂) × Jian carp (♀) showed high SCA with regard to body weight. Both Heilongjiang carp (♂) × Jian carp (♀) and Heilongjiang carp (♂) × Huanghe carp (♀) had higher heterosis compared to their purebreds. Significant positive phenotypic correlations were also observed between body weight and body length, thickness and height. The aforementioned results listed were identified as the foundation for common carp selective breeding programs.Keywords: Common carp, cross-breeding, heterosisAfrican Journal of Biotechnology Vol. 12(22), pp. 3514-3521

Rested upon Box-Behnken experimental design and response surface method, the joint effect of temperature, salinity and pH on the fertilization and hatching in Nile tilapia was studied under laboratory conditions. Results showed that the linear and quadratic effects of temperature, salinity and pH on fertilization and hatching were all statistically significant (P 0.05). Regressions of fertilization and hatching towards temperature, salinity and pH were established, with the determination coefficient being 99.17% for fertilization and 99.79% for hatching, and could be used for prediction. By utilizing statistical optimization technique, the optimal temperature/salinity/pH combinations were attained: 27.6°C/9.3 ppt/7.5 for fertilization, at which the maximum fertilization was 87.7%, with the desirability being 92.11%; and 27.1°C/9.2 ppt/7.4 for hatching, at which the maximum hatching rate reached 81.2%, with the desirability as high as 96.74%. It could be said that the fertilization and hatching concurrently culminated at the 27.3°C/9.2 ppt/7.4 combination. It can be envisioned that the application of these results derived would give an impetus to the tilapia seed production efficiency and in turn to the development of tilapia husbandry.

Central composite face-centered design(CCF) and response surface methodology were used in the experiment to examine the combined effect of temperature(12—34℃) and salinity(0—26) on the Na+-K+-ATPase activity from the gill of tilapia juveniles(GIFT strain)(mean body length(4.3±0.105)cm and mean body weight(2.45±0.153)g).The results showed that:(1)The linear and quadratic effects of temperature and salinity on the Na+-K+-ATPase activity were highly significant(P0.01),and the interactive effect between temperature and salinity was nonsignificant(P0.05);(2)Using the response surface method,the Na+-K+-ATPase activity varied with increasing temperature and salinity in a curvilinear way;(3)The model equation of the enzyme activity towards temperature and salinity was established,with R2=0.9829 and Pred.R2=0.855(P0.01).The model equation could be practically used for forecasting the gill Na+-K+-ATPase activity in GIFT Nile tilapia juveniles;(4)Via applying statistical optimization of the response of interest,results showed that the optimal factor combination was 24.15℃/11.75,at which the minimum Na+-K+-ATPase activity,0.62μmolPi·mg-1pr·h-1,was reached,with the desirability as high as 0.961.The Na+-K+-ATPase activity can be used as an indicator of growth of GIFT Nile tilapia juveniles.In general,It can be said that the environment in which the Na+-K+-ATPase activity is weaker is suitable for the tilapia juvenile growth,and in this case the metabolism of tilapia is more efficient,and the energy consumed for osmoregulation is smaller.

Based on Box–Behnken experimental design and response surface method, the joint effect of temperature (16–36°C), salinity (0–22 ppt) and rearing density (200–1000 fish.m−3) on the specific growth rate (SGR) and feed conversion rate (FCR) of Nile tilapia juveniles were studied under laboratory conditions. The entire experiment lasted for 1 month (30 days). Results showed that the linear and quadratic effects of temperature, salinity on both growth and feed utilization were highly statistically significant (P 0.05). Interactions between temperature and salinity, and between salinity and rearing density on the growth statistically differed from zero (P

Macrobrachium rosenbergii,also known as the giant river prawn,the giant freshwater prawn or the Malaysian prawn,is the most important cultivated species of freshwater shrimp in the world.This species(as well as other Macrobrachium) is commercially important for its value as a food source.In China,the production of M.rosenbergii has been increasing in recent year.However,cultured M.rosenbergii in China as well as in other parts of the world have suffered from various stress factors such as ambient temperature,stocking density,physicochemical parameters,transport,and storage.Stress means the sum of nonspecific responses of organisms to various acute stimuli inside and outside.It is a physiological response of any organisms in the long evolution process to extend its adaptation,but excess response,which inhibits immunity,improves the free radical contents,destroys the homeostasis between producing and cleaning-up of free radical,and attacks the double bond of polyunsaturated fatty acid in plasma membrane,the last leading to increase the lipid peroxidation contents and lipid peroxidation injury.So these are many disadvantageous impacts on organisms and it causes fish to infect diseases even to die.Therefore,how to alleviate stress response is the research focus in this field.The present research falls on substances,which can strengthen immunity of organisms and alleviate stress,e.g.vitamin C,vitamin E,lipid acid,metal ion,fructose,astacin.Chinese herbal medicines have many merits:natural,highly effective,low toxicity,low side effects,and rich in resources.Chinese herbal medicines have many effective components,such as organic acids,alkaloid,saccharide,volatile oil,wax,glycoside,tannic acid substance and some unknown factors that can elevate fish immunity and enhance the growth.However,few reports have been found in studying the effects of Chinese herbal medicines on the hepatopancreas antioxidative capacity and the level of HSP70 mRNA under high temperature of M.rosenbergii.In view of this,M.rosenbergii were divided into 5 groups randomly.The control were fed with basal diet,the others the treated groups were fed with basal diet supplemented with 0.05%,0.10%,0.20%,0.40% anthraquinone extracts for 10 weeks,respectively.After that,shrimp were stressed by high temperature at 35 ℃ for 48 h continuously.The changes of total antioxidative capacity(T-AOC),catalase(CAT),superoxide dismutase(SOD),nitrogen oxide(NO),malondialdehyde(MDA) and the mRNA level of heat shock protein 70(HSP70) in hepatopancreas before and after the stress were investigated.The results showed that compared with the control,0.05% dose of anthraquinone extract could elevate CAT,SOD activities and reduce MDA concentration,0.20% dose group improved T-AOC and NO content and reduced MDA concentration,and 0.10%,0.20% doses groups improved also the relative content of HSP70 mRNA before the stress.After 35 ℃ high temperature stress,T-AOC,CAT activities,SOD activities,and NO concentrations in hepatopancreas were decreasing in all groups of which the control relatively lower and 0.10%-0.20% doses groups were relatively higher,while MDA contents were increasing trend in all groups of which the control was relatively higher and 0.10%-0.20% doses groups were relatively lower.The relative content of HSP70 in hepatopancreas 6 h after the stress in 0.10% and 0.20% doses groups were higher than those of the control.It is concluded that ingestion of 0.10%-0.20% doses of anthraquinones extracts could improve the antioxidative capacity,elevate the relative content of HSP70 mRNA and help prevent negative effects of high temperature stress to a certain degree.

Molecular marker-assisted selection increases the selection precision and reduces the number of generations required to achieve a desired improvement. Here, we report on the relationship between polymorphism in the insulin-like growth factor II (IGF2) gene and growth trait in a genetically improved farmed tilapia strain (GIFT strain). We first isolated the entire IGF2 (5517 bp), including the complete reading frame and three interrupting introns. After sequence comparison of IGF2 from 10 individuals, we identified nine polymorphic sites in intron 1 and intron 3, and four silent mutation sites in exon 2 and exon 3. Four of the 13 polymorphic sites were examined and genotyped using various technologies, including PCR-RFLP, tetra-primer PCR and PCR-PAGE among 192 experimental individuals. Regression analyses demonstrated that two sites, G161A in exon 3 and the microsatellite locus in intron 3, were significantly associated with male GIFT growth. These two putative markers will be further validated in our future breeding project.

Macrophages from the head kidney (HK) and peripheral blood leucocytes were isolated fromCyprinus carpio by Percoll gradient density centrifugation, cultured in vitro and exposed to different concentrations of the immunomodulator lentinan. To evaluate the immunostimulating effects of lentinan, proliferation of the peripheral blood leucocytes, respiratory burst of macrophages and interleukin-1β (IL-1β) gene mRNA expression of macrophages were investigated by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide], NBT (nitroblue tetrazolium) reduction, Griess reaction and real-time polymerase chain reaction (PCR). Results showed that proliferation of peripheral blood leucocytes after 24 h incubation by the induction of lentinan at 100 and 1000 μg/ml was markedly stimulated. Lentinan at 1, 100 and 1000 μg/ml could significantly induce superoxide anions in macrophages. Production of nitric oxide by HK macrophages after 96 h incubation by lentinan showed that it had no conspicuous effect on nitrogen burst activity of macrophages. Moreover, it inhibited the nitrogen burst activity at higher doses. The expression of IL-1β in the HK macrophages after 24 h of polysaccharide stimulation showed that lentinan stimulated IL-1β expression in the head kidney in carp. Lentinan can modulate the immune response of C. carpio.