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1.
Nile tilapia exhibits strong sexual growth dimorphism. The potential role of sex steroid hormones in sexual growth dimorphism is not fully understood. We investigated the effects of estradiol (E2) and testosterone (T) on growth rate, plasma sex hormones, and expression of growth hormone (GH)‐insulin‐like growth factor (IGF) axis genes and muscle regulatory factor (MRF) genes in female and male Nile tilapia. The results revealed that serum concentrations of E2 and T were significantly higher after correlative injection (P < 0.05). Compared to male fish, female fish had lower growth rates. E2 increased growth performance in females with no significant effects on males, whereas T significantly increased growth performance in males, with no significant effects on females. In females, E2 significantly increased expression of ghr1, ghr2, igf1, and igf2, while T decreased igf2 and increased ghr1 and ghr2 expression. In males, T increased expression of igf1, igf2, ghr1, and ghr2, and E2 decreased expression of igf1, ghr1, and ghr2. Additionally, E2 and T enhanced the expression of MRF genes (myod1, myod2, myog, and myf5) in female and male fish, respectively. The results suggest that sex steroid hormones play a role in sexual growth dimorphism by regulating the expression of GH‐IGF axis and MRF genes.  相似文献   

2.
Multispecies herbs and probiotic bacteria offered to fish might enhance their immune response and increase disease resistance, but the dose effects of herbal‐probiotic application remain unclear. Therefore, the effect of herbal‐probiotic mixtures of traditional Chinese medicine (TCM) of composition Astragalus membranaceus, Angelica sinensis, Crataegus hupehensis and probiotic Bacillus species (BS) of composition Bacillus subtilis and Bacillus lincheniformis as natural immunostimulants in tilapia Oreochromis niloticus have been investigated. Fish were randomly divided into four groups: control diet (CT), TCMBS1 [TCM at 3 g/kg and BS at 7 g/kg], TCMBS2 [TCM at 5 g/kg and BS at 5 g/kg], TCMBS3 [TCM at 7 g/kg and BS at 3 g/kg]. Tilapia in the TCMBS3 group showed significant improvement in weight gain, specific growth rate, and lowered feed conversion ratio compared with other treated groups and the control. Concerning immune indexes, all treated groups significantly enhanced lysozyme, superoxide dismutase, catalase, protease and antiprotease activities, with highest values in catalase and antiprotease activities in TCMBS3 compared with control. TCMBS3 demonstrated higher expression of βeta‐defensin, lysozyme, heat shock protein 70, catalase and transforming growth factor‐βeta compared with other treated groups or the control group in both mid‐intestines and head‐kidney. After challenge with Streptococcus agalactiae, the best survival was found in TCMBS3 (97%), followed by TCMBS2 (73%), and TCMBS1 (69%) compared with the CT (35%). Collectively the present results suggest that TCMBS3 dose might potentiate a higher immune response and disease resistance in fish.  相似文献   

3.
Prochilodus lineatus (curimbatá), from the Procholodontidae family, is a Brazilian freshwater fish, which is important commercially, nutritionally and ecologically. It is encountered in the Rio da Prata Bay in Southern South America. Studies on the immune system of this fish are scarce, but the physiological mechanisms of the species are analogous to those of other vertebrates. Thus, this work discusses the present study, which correlates P. lineatus leukocytes and the generation of reactive oxygen species after modulatory stimuli. Leukocytes were characterized by light and electron transmission microscopy and investigated by the generation of H2O2 and O2 ?, using phenol red, flow-cytometry and electron transmission histochemistry. The study determined that monocytes and neutrophils are the main cells responsible for generating O2 after stimulation with phorbol myristate acetate. Superoxide dismutase successfully inhibited the generation of reactive oxygen species in neutrophils and monocytes, but stimulated generation when in association with phorbol myristate acetate. Fish leukocyte samples from P. lineatus showed cross-reactivity with antibodies directed against human NADPH-oxidase antibody subunits (p47phox and p67phox). Thus, catalase enhanced the presence of p47phox. Neutrophil mitochondria were shown to be generators of H2O2 (charged by cerium precipitate), being enlarged and changing their format. The present study contributes to a better understanding of the respiratory burst pathways in this species and suggests mitochondria as the organelle responsible for generation of reactive oxygen species.  相似文献   

4.
为进一步研究大口黑鲈(Micropterussalmoides)糖稳态调控特性,本研究克隆了糖稳态调控基因gp1、gp2、pepck1、pepck2、hk、pfk和g6p,分别编码878、842、635、624、918、780和338个氨基酸序列,并进行了进化树、空间分布和禁食对其基因表达影响的分析。多序列比对和进化树分析显示,这些基因与其他脊椎动物的同源序列具有较高相似性。组织表达分析结果显示这些基因主要集中分布于肝脏和肌肉,但呈现出组织表达差异性。其中,gp1在肌肉表达量最高,肝脏次之,在脾脏表达量最低。gp2在肌肉中的mRNA水平也最高,在心脏、肝脏表达也较为丰富。pepck1主要分布在肝脏和肠,在脑、脾脏、肾脏和脂肪中分布较少。pepck2在肝脏和脑中高表达,而在脾脏和鳃中表达量最低。对于hk,其在肝脏、肌肉和心脏的mRNA水平显著高于其余组织。肝脏中g6p的表达也显著高于其余组织。除此之外,其在肌肉、肠和脂肪中分布也较为丰富。pfk的mRNA水平在肝脏和心脏最高,其次是肠和鳃。对实验大口黑鲈禁食后发现,肝脏gp2、pepck2和g6p的表达从禁食第6小时开始上调并持续到24h...  相似文献   

5.
应用引物退火控制技术(ACP)筛选尼罗罗非鱼雌雄鱼肌肉组织差异表达基因,寻找与雌雄鱼肌肉生长发育相关的候选基因。本实验从同等条件下养殖的尼罗罗非鱼群体中随机选取雌、雄鱼各5尾组成RNA池,采用引物退火控制技术,分析了两组个体肌肉组织差异表达基因。利用20对随机引物差异显示扩增,共获得8条ESTs,其中5个已知的ESTs分别为转录变体3(LOC100691543)、60S核糖体蛋白(RL3)、小白蛋白β样蛋白、肌型肌酸激酶M2-CK和转录因子Sox4,其余3个为未知的ESTs。实时定量PCR分析各差异表达基因在尼罗罗非鱼雌雄肌肉组织中的表达发现,8个差异表达基因中转录变体3与ACP6-Y在尼罗罗非鱼雄鱼肌肉组织中的表达均极显著高于雌鱼(P0.01),ACP3-X、60S核糖体蛋白(RL3)、小白蛋白β样蛋白、ACP15-X、肌型肌酸激酶M2-CK与转录因子Sox4在尼罗罗非鱼雌鱼肌肉组织中的表达均极显著高于雄鱼(P0.01)。结果表明,应用引物退火控制技术筛选获得了8个可能参与了雌雄鱼肌肉生长发育调控的ESTs,为进一步筛选雌雄鱼肌肉生长发育相关候选基因奠定了基础。  相似文献   

6.
Growth hormone plays important roles in various physiological processes such as growth, metabolism, and reproduction. In this study, two cDNAs encoding growth hormone receptor (GHR) were isolated from the liver of zanzibar tilapia (Oreochromis hornornum). The two cDNAs were 2,831 and 2,044 bp in length and named GHR1 and GHR2, respectively. GHR1 and GHR2 shared 57.4% similarity in nucleotide sequences and 33.5% similarity in deduced amino acid sequences. Consequently, it was presumed that they were two different genes. Conserved regions of GHR1 and GHR2 in zanzibar tilapia were different from those of other vertebrates. For example, conserved box2 regions of GHR1 and GHR2 in zanzibar tilapia were, respectively, WVELM and WVEFT, while it was WVEFI for GHRs in other vertebrates. Similar to other fish species, GHR1 and GHR2 were expressed in brain, gill, liver, muscle, spleen, gonad, stomach, kidney, and pituitary in zanzibar tilapia. The expression levels were the highest in liver. Unlike fathead minnow (Pimephales promelas) and mossambique tilapia (O. mossambicus), the expression levels of GHR1 in most female fish tissues were higher than those in male fish. No significant difference in GHR2 expression was found in all the tissues in male and female of zanzibar tilapia. Under fasting condition, the expressions of GHRs and IGF-II were significantly up-regulated (P < 0.05) in liver, while the expression of IGF-I remained stable. This observation would contribute to understanding the evolution of the GHR family in further investigation of growth regulation of zanzibar tilapia.  相似文献   

7.
刘灵  徐俊  马盼  李安兴 《水产学报》2019,43(5):1308-1316
实验采用BALB/c小鼠作为实验动物,旨在建立尼罗罗非鱼无乳链球菌毒力测定的BALB/c小鼠模型。BALB/c小鼠经腹腔注射尼罗罗非鱼源无乳链球菌建立感染模型,比较了尼罗罗非鱼源无乳链球菌分别感染尼罗罗非鱼和小鼠的LD_(50)差异,分别测定了不同毒力尼罗罗非鱼无乳链球菌对尼罗罗非鱼和小鼠的毒力。结果显示,小鼠经腹腔注射无乳链球菌,在24 h内出现死亡现象,且对小鼠脑、肝脏、脾脏、肾脏等组织造成损伤。3次测定尼罗罗非鱼无乳链球菌TFJ0901对尼罗罗非鱼和小鼠LD_(50)分别为7.7×10~7、2.2×10~8、3.5×10~9 CFU/mL和405、361、419 CFU/只。将无乳链球菌TFJ0901和THN0901感染尼罗罗非鱼(1.0×10~7 CFU/mL)和小鼠(100 CFU/只),尼罗罗非鱼和小鼠存活率分别为100%、6.7%±5.8%和100%、0,其存活率都具有显著性差异。将无乳链球菌TFJ0901和TFJ-F感染尼罗罗非鱼(3.0×10~8 CFU/mL)和小鼠(2 500 CFU/只),尼罗罗非鱼的存活率分别为73.3%±11.5%和80.0%±10.0%,存活率差异不显著,小鼠存活率分别为13.3%±11.5%和100.0%,存活率具有显著性差异。研究表明,本实验成功建立了BALB/c小鼠作为尼罗罗非鱼源无乳链球菌毒力测定的稳定模型,测定不同毒力的尼罗罗非鱼源无乳链球菌对小鼠毒力与对尼罗罗非鱼毒力一致,且该模型能够区分尼罗罗非鱼模型难以区分的毒力相近的无乳链球菌。  相似文献   

8.
The current study aimed to investigate the effects of dietary soybean β‐conglycinin on growth performance and intestine apoptosis in juvenile grass carp (Ctenopharyngodon idella). For fish fed with the 80 g β‐conglycinin/kg diet for 7 weeks, the specific growth rate and feed intake were decreased. In the proximal intestine, dietary β‐conglycinin did not induce DNA fragmentation, tended to decrease the reactive oxygen species (ROS) content, and decreased ROS‐generating enzyme (NADPH oxidase [NOX]) activity. Subsequently, in the mid‐intestine, dietary β‐conglycinin caused DNA fragmentation, tended to increase the ROS content, increased caspase‐3, caspase‐8 and caspase‐9 activities, upregulated the mRNA levels of proapoptotic molecules (apoptotic protease‐activating factor‐1 [Apaf1] and Bcl‐2‐associated X protein [BAX]) and mitogen‐activated protein kinase (MAPK)‐related signal molecules (Jun N‐terminal kinase (JNK) and p38 MAPK) and increased the protein levels of p38 MAPK and phospho‐p38 MAPK. Moreover, in the distal intestine, dietary β‐conglycinin induced DNA fragmentation, elevated NOX activity and the ROS content and increased caspase‐3, caspase‐8 and caspase‐9 activities, death ligand (TNF‐α) mRNA expression level, and p38 MAPK and phospho‐p38 MAPK protein levels. In summary, dietary soybean β‐conglycinin suppressed fish growth and inconsistently caused apoptosis among the different intestinal segments which was partially associated with ROS‐mediated MAPK signalling.  相似文献   

9.
This study investigated the effects of nursing duration on the subsequent performance of rohu (R) Labeo rohita and mrigal (M) Cirrhina mrigala in polyculture with monosex male Nile tilapia (T) Oreochromis niloticus at four levels of pond fertilization. Nile tilapia, rohu and mrigal were stocked at a ratio of 4:1:1 in a 90‐day trial based on 40 20‐m2 pens fixed in four 400‐m2 earthen ponds. Growth of carp fingerlings during prolonged nursing (5 or 12 months) was stunted compared with fish nursed over a conventional duration of 3 months (3) but showed superior growth subsequently. Mean daily weight gain of stunted rohu (12) ranged from 2.2 to 2.8 g per fish day?1 compared with 1.1–1.6 g per fish day?1 for younger fish (3). The comparable ranges for mrigal were 1.9–2.8 and 1.4–2.1 g per fish day?1. Growth of Nile tilapia was inversely related to duration of carp nursing at the four levels of fertilization. Nile tilapia showed more response to increasing levels of fertilizer input (Y=?1.421+1.716X, where Y is the daily weight gain of Nile tilapia and X is the fertilizer level, r2=0.98, P<0.01, n=12). At a high level of fertilization (3.0 kg N:1.5 kg P ha?1 day?1), performance of stunted fingerlings (5 and 12) of both rohu and mrigal was similar (range 2.3–2.8 g per fish day?1, P>0.05), but younger mrigal (M3) grew faster than rohu (2.1 g per fish day?1 and 1.6 g per fish day?1 respectively). Older rohu (12) appeared to perform particularly well, and Nile tilapia poorly at the lowest level of fertilization (1.5 N:0.75 kg P ha?1 day?1), suggesting the impact of age of seed on competition within polycultures. The net fish yield (NFY) of tilapia was not affected significantly (P>0.05) by differential stocking age of carps; therefore, combined NFY of the three experimental fish species was not affected by the age of carp, as tilapia was the dominant species in polyculture. The highest combined NFY of all species in the most intensively fertilized pond (3.0 N:1.5 P kg ha?1 day?1) was calculated at 4.06±0.08 g·m?2 day?1, which was significantly higher (P<0.001) than the yield (1.82±0.12 g·m?2 day?1) from the pond with the lowest fertilization. At the highest fertilizer level, tilapia, rohu and mrigal contributed 72%, 14% and 14%, respectively, to the NFY, whereas the ratio was 60%, 20% and 20% at the lowest fertilization level. The study indicated that yields from tilapia in polyculture with the two carp species in more eutrophic water can be optimized if advanced nursing of carps is practised. Moreover, higher inputs of inorganic fertilizer and advanced nursing of carp are economically attractive under Bangladeshi conditions. Advanced nursing of rohu also improves its performance in more extensive systems when tilapia densities are high.  相似文献   

10.
Tilapia aquaculture is one of the fastest‐growing segments of fish production in Brazil. Nile tilapia (Oreochromis niloticus) is largely cultivated in the state of Parana, where Streptococcus agalactiae is the cause of severe disease outbreaks. The objective of this paper was to evaluate an inactivated S. agalactiae vaccine in tilapia for the control of streptococcal disease outbreaks. Tilapia, weighing approximately 20 g each, were intraperitoneally (i.p.) inoculated with 0.1 mL of the vaccine at a dose of 2.0 × 108 colony‐forming unit (CFU) mL?1. One group of tilapia (treatment 1) received one vaccine dose, and the other group of tilapia (treatment 2) received two doses, with an interval of 21 days. The control group was i.p. inoculated with 0.1 mL tryptic soy broth fish?1. Immunized and control tilapia were i.p. challenged with 0.1 mL of 3.0 × 107 CFU mL?1 at 30 days post vaccination. The fish were monitored daily for disease signs and for mortality for 16 days post challenge. A statistically significant difference (P=0.0045) was found between the mortality of treatments 1 and 2. The value of relative per cent of survival of 83.6% and 96.4%, respectively, indicate that this vaccine was efficient in Nile tilapia.  相似文献   

11.
为了解草鱼(Ctenopharyngodon idellus)NADPH多酶复合体的基因结构及其在机体的防御体系中的功能,利用RT-PCR结合RACE-PCR的方法,克隆草鱼NADPH氧化酶的2个调节亚基p40phox和p47phox的cDNA,对其编码的氨基酸序列进行了同源性比较和功能域分析,同时对这两个亚基在草鱼不同组织中的差异性表达进行分析。结果显示:p47phox亚基cDNA序列全长为1 589 bp,开放阅读框长度为1 233 bp,编码410个氨基酸;p40phox亚基cDNA序列全长为2 103 bp,开放阅读框为1 068 bp,编码355个氨基酸。这两个亚基编码的氨基酸序列与其他鱼类的同源性在68%~96%,具有其它鱼类类似的PX,SH3,PB1和PC功能域。组织差异性表达分析结果表明:2个调节亚基在草鱼胸腺、心脏、头肾、鳃、肠、肝、肾、脾和皮肤组织中均有表达,在不同组织中的表达强度略有差异,在心脏、胸腺中表达水平最高,在肝脏中表达水平较低,但是不同组织之间的表达水平差异不显著(P>0.05)。  相似文献   

12.
Streptococcosis causes economic losses due to mass mortality at all culturing stages in Nile tilapia, Oreochromis niloticus, and red tilapia, Oreochromis sp., farming throughout Thailand. Diseased tilapia collected from outbreak areas during 2003–2012 were examined using histopathological, biochemical, and molecular tools. Infected fish showed clinical signs of septicemia, and bacteria were found in visceral organs. All gram‐positive cocci isolates were negative to catalase and oxidase, and exhibited β‐hemolysis; however, they possessed various biochemical profiles. PCR amplification of the 16S rRNA gene was used for 165 samples, and resulted in identification of 143 (86.67%) with Streptococcus agalactiae and 14 (8.48%) with Streptococcus iniae, and 8 (4.85%) with mixed infection. High similarity (≥98%) of 16S rRNA gene sequences to the reference strain S. agalactiae (accession no. EF092913) and S. iniae ATCC29178 type strain was observed in the typing of S. agalactiae and S. iniae from Thai farmed tilapia. This investigation documented that at least two species of streptococcal bacteria, S. agalactiae and S. iniae, were involved in tilapia streptococcal infection in Thailand. The molecular recognition of the etiologic agents showed that S. agalactiae was the dominant species that cause disease in all culture areas, whereas S. iniae were discovered only in cases from the northeastern and central regions.  相似文献   

13.
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14.
The present research investigated the effect of stocking density on pond (75 m2, depth 1.2 m) production of Nile tilapia (Oreochromis niloticus) and freshwater prawn (Macrobrachium rosenbergii) stocked at a fixed 3:1 tilapia:prawn ratio. Three stocking densities were tried in triplicate: 20 000 ha−1 (treatment TP‐20), 30 000 ha−1 (TP‐30) and 40 000 ha−1 (TP‐40). The ponds were provided with bamboo as substrate for periphyton development. Bamboo poles (mean diameter 5.5 cm and 5.0 poles m−2) were posted vertically into pond bottoms, resulting in 60% additional substrate area in each pond. On average, 43 genera of algae and 17 genera of zooplankton were identified from pond water, whereas 42 genera of algae and six genera of microfauna were attached to bamboo substrates. No differences were observed between treatments in the ash‐free dry matter (AFDM), chlorophyll a and phaeophytin a content of periphyton (P>0.05). Survival of tilapia and prawn and individual weight gain of tilapia were lower (P<0.05) in treatment TP‐40. The net yields were higher (P<0.05) in treatments TP‐30 (2209 and 163 kg ha−1 105 day−1 of tilapia and prawn respectively) and TP‐40 (2162 and 141 kg ha−1 of tilapia and prawn respectively) than in treatment TP‐20 (1505 and 136 kg ha−1 of tilapia and prawn respectively). The net tilapia yields were quadratic correlated (R2=0.92) with fish stocking density. The cost–benefit analysis shows that the net profit margin was highest in treatment TP‐30 (69%), followed by TP‐20 (50%) and TP‐40 (44%).  相似文献   

15.
Precise regulation of gene expression is required for a proper transition through the different phases of the ovarian cycle. To study ovarian gene expression in teleosts, we constructed an adult ovary cDNA library of tilapia, Oreochromis mossambicus, and analyzed the gene expression profile using an expressed sequence tag-based strategy. Of 768 random clones, 530 clones, with insert lengths of > 100 base pairs (bp), were assembled into 474 tentative unique genes (TUGs), including 34 contigs and 440 singlets. Among these, 230 TUGs were highly homologous to known genes in public databases, while others exhibited a low sequence homology or no significant matches to known sequences; these are called novel genes here. The abundance of each identified gene was assayed to evaluate its relative importance in ovarian functions. In addition, we analyzed the expression patterns for 6 development-and reproduction-related genes, including cofilin, fibulin-4, glucosamin-6-phosphate deaminase 2 (GNPDA), MCM-6, stathmin, and zona pellucida C5 (ZPC5), as well as 9 novel genes. Results showed that GNPDA, MCM6, ZPC5, and 7 of the novel genes, including O34, O141, O148, O149, O243, O258, and O319, were predominantly expressed in the ovary and/or testis. In addition, the expression patterns of gonad-specific novel genes in tilapia larvae were differentially affected by treatment with 17 β-estradiol and 17 α-methyltestosterone during the sex-sensitive period.  相似文献   

16.
Francisella noatunensis subsp. orientalis is a causative agent of systemic granulomatous disease in tilapia. The present study was designed to understand the genetic and phenotypic diversities among Taiwanese Fno isolates obtained from tilapia (n = 17) and green Texas cichlid (Herichthys cyanoguttatus) (n = 1). The enzymatic profiles of the isolates were studied using the API ZYM system. Phylogenetic tree analysis of the 16S rRNA and housekeeping gene and pulsed‐field gel electrophoresis (PFGE) were carried out to determine the genotypic characters of all isolates. The phylogenetic tree showed similarity of 99%–100% nucleotide sequences of 16S rRNA and housekeeping genes compared to the Fno references genes from GenBank database. Comparatively, the results revealed an identical profile of enzymatic and PFGE pattern which was distincted from that of F. philomiragia. To understand the pathogenicity, the isolates were intraperitoneal injected to tilapia the gross lesions were observed concomitant with natural outbreak. Median lethal dose upon Nile tilapia and red tilapia were 9.06 × 103 CFU/fish and 2.08 × 102 CFU/fish, respectively. Thus, our data provide understanding the epidemiology of Taiwanese Fno isolates, and help in development of future control and prevention.  相似文献   

17.
The present research evaluated the effects of four feeding stimulants on feed intake (FI), growth performance, body composition, serum biochemical parameters, digestive enzyme activities and appetite‐related gene expression for juvenile GIFT tilapia. Five experimental high plant‐based diets (with 0, 0.4 g kg?1 dimethyl‐β‐propiothetin (DMPT), 0.6 g kg?1 dimethylthetin (DMT), 1.8 g kg?1 tryptophan (Trp) and 6 g kg?1 betaine (Bet), respectively supplemented) were fed to juvenile GIFT tilapia (Oreochromis sp.) (3.34 ± 0.01 g) for 8 weeks. The results showed that FI was significantly increased by Trp and DMT. The highest specific growth rate (SGR) and protein efficiency ratio (PER) was observed for fish fed Bet diet, followed by DMT. Serum triglyceride was significantly increased by DMPT. Fish fed Bet diet showed significantly higher intestinal protease, liver protease and intestinal amylase activities. The neuropeptide Y (NPY) mRNA expression in brain was significantly improved by Trp, and ghrelin mRNA expression in stomach was significantly increased by DMT. It is concluded that supplementation of Trp or DMT could act as an effective feeding stimulants (FS) in high plant‐based diets for juvenile GIFT tilapia, which might be associated with the relatively higher orexigenic (NPY or ghrelin) genes expression, and supplementation of Bet could improve SGR, PER and reduce feed conversion ratio (FCR) of juvenile GIFT tilapia.  相似文献   

18.
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19.
Cage‐pond integration system is a new model for enhancing productivity of pond aquaculture system. A field trial was conducted using African catfish (Clarias gariepinus) and Nile tilapia (Oreochromis niloticus) in cages and carps in earthen ponds. There were four treatments replicated five times: (1) carps in ponds without cage, (2) tilapia at 30 fish m?3 in cage and carps in open pond, (3) catfish at 100 fish m?3 in cage and carps in open pond, (4) tilapia and catfish at 30 and 100 fish m?3, respectively, in separate cages and carps in open pond. The carps were stocked at 1 fish m?2. The cage occupied about 3% of the pond area. The caged tilapia and catfish were fed and the control ponds were fertilized. Results showed that the combined extrapolated net yield was significantly higher (P < 0.05) in the catfish, tilapia and carps integration system (9.4 ± 1.6 t ha?1 year?1) than in the carp polyculture (3.3 ± 0.7 t ha?1 year?1). The net return from the tilapia and carps (6860 US$ ha?1 year?1) and catfish, tilapia and carps integration systems (6668 US$ ha?1 year?1) was significantly higher than in the carp polyculture (1709 US$ ha?1 year?1) (P < 0.05). This experiment demonstrated that the cage‐pond integration of African catfish and Nile tilapia with carps is the best technology to increase production; whereas integration of tilapia and carp for profitability.  相似文献   

20.
黏膜及其表面的共生菌群是鱼类抵御外界不利环境的第一道屏障。为探索养殖罗非鱼表皮和鳃黏膜共生菌菌群的结构特征是否与其健康状况间存在相关关系,本研究运用高通量测序技术,以无乳链球菌腹腔注射攻毒48 h后存活和濒死尼罗罗非鱼为检测对象,检测攻毒前后罗非鱼表皮和鳃黏膜共生菌群落结构差异。结果显示,健康尼罗罗非鱼表皮和鳃黏膜共生菌均存在优势菌群,主要为特吕珀菌属、硫杆菌属、弓形杆菌属、海单胞菌属和弧菌属。人工感染无乳链球菌后存活尼罗罗非鱼表皮和鳃黏膜共生菌菌群与感染前无显著差异;与存活组相比,濒死尼罗罗非鱼的表皮和鳃黏膜共生菌菌群多样性下降,其中弓形杆菌属、假交替单胞菌属、海单胞菌属、假单胞菌属和弧菌属等含量显著下降,链球菌属含量占总菌群的55.30%±1.24%,表明养殖尼罗罗非鱼表皮和鳃黏膜共生菌群落结构可能与其健康状况相关。  相似文献   

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