A twelve week experiment was conducted to compare the effects of diets with plant-based and animal-based ingredients on growth and gonad development of Clarias gariepinus. One hundred and 12 sub-adult C. gariepinus wi...A twelve week experiment was conducted to compare the effects of diets with plant-based and animal-based ingredients on growth and gonad development of Clarias gariepinus. One hundred and 12 sub-adult C. gariepinus with an average weight of 205 ×5.09 g, were stocked in six concrete tanks (9 × 4 × 2 m3) containing 20 fish each. Experiment had 3 replicates and animals fed daily at 5% body weights. There was no significant difference (P 〈 0.05) in proximate compositions of the two experimental feeds and controls. Fecundity, gonad weight and gonasomatic index were higher in fish fed diet 13 than A and C. Similarly, growth indices were higher in fish fed diet B than in A and C. Histology of gonads showed a faster development of oocytes of eggs in fish fed animal-based ingredients than plant-based and combined plant and animal diets. Although there were slight differences in growth parameters and gonad development in favor of feed with animal-based ingredients, plant-based feed compared favorably in the growth and gonad development of C. gariepinus. Plant-based ingredients are recommended on the basis of affordability and availability as substitute for animal-based ingredients in C. gariepinus feed.展开更多
The factor in the germline alpha(figla), as a member of the basic helix-loop-helix family, has been reported to be involved in ovary development in mammals and teleosts. However, the regulatory mechanisms of figla in ...The factor in the germline alpha(figla), as a member of the basic helix-loop-helix family, has been reported to be involved in ovary development in mammals and teleosts. However, the regulatory mechanisms of figla in teleosts remain unclear. Here,figla in P. olivaceus(Pofigla) was characterized with encoding a 202 amino acid protein that contains a conserved basic region and helix-loop-helix(HLH) domain. Amino acids alignment and synteny analysis revealed that Pofigla was conserved with the orthologous gene sequences in other vertebrates. The results of qRT-PCR showed Pofigla was maternally inherited during embryonic development. For tissue distribution, Pofigla showed a sexually dimorphic gene expression in the gonad of different genders, with a higher expression in ovary than in testis. In situ hybridization(ISH) results demonstrated Pofigla was specifically expressed in germ cells including oocytes, spermatogonia and spermatocytes. By screening and analyzing two proximal regions(-2966/-2126 and-772/-444) with high promoter activity, we found SOX5, LEF1, FOXP1 and GATA1 may play important roles in the transcriptional regulation of Pofigla. Furthermore, we observed the co-localization between Figla and LEF1 in HEK 293T cells. And the significant up-regulation effect of the canonical Wnt signaling pathway on the expression of Pofigla was found in cultured ovarian cells. This study provided the first evidence that figla not only has an important function in ovary development, but also plays some potential roles in testis development and/or male germ cell differentiation during early testis development in P. olivaceus. The results provide valuable reference in exploring the regulatory network of figla in teleost.展开更多
The sea urchin Heliocidaris crassispina has northern expanded in geographic range to Toga Bay,Oga Peninsula in the Sea of Japan due to the global warming.To demonstrate the gonad traits and age structure of H.crassisp...The sea urchin Heliocidaris crassispina has northern expanded in geographic range to Toga Bay,Oga Peninsula in the Sea of Japan due to the global warming.To demonstrate the gonad traits and age structure of H.crassispina in the central range and compare the difference with those in northern extended range,we collected 100 H.crassispina individuals from a barren off Shitsumi,Fukui(central range),in August 2018.Their growth,gonad traits(size,development and color),and sex ratio were investigated and compared with those in Toga Bay,in August 2014(extended range).The successive 2012–2016 year classes of H.crassispina indicated successive juvenile recruitment in the central range,as found in the extended range.The individuals at three years old in central range were obviously larger than those in the extended range,showing large test diameter and body weight,possibly due to the higher temperature in central range than that in northern extended range.In addition,a balanced sex ratio in the central range was found,in contrast to the female-skewed sex ratio found in the extended range.Gonadal development was sex-and site-dependent.The testicular development in the central range was not only delayed in comparison to ovarian development,but also less delayed than those in the extended range,which possibly attribute to the higher water temperature in the central range.A significantly lower male gonad index and L*(lightness)value was recorded in central ranges compared to that in extended range,possibly due to the releasement of sperm of H.crassispina in central ranges.展开更多
Artificial lighting regimes have been successfully used to inhibit sexual maturity of Atlantic salmon in confinement.However,when these operations are applied in commercial recirculating aquaculture systems(RAS) using...Artificial lighting regimes have been successfully used to inhibit sexual maturity of Atlantic salmon in confinement.However,when these operations are applied in commercial recirculating aquaculture systems(RAS) using standard lighting technology,sexual maturation is not suppressed.In this study,an L_9(3~3) orthogonal design was used to determine the effects of three factors(spectral composition,photoperiod,and light intensity) on the gonadal development of Atlantic salmon in RAS.We demonstrated that the photoperiod at the tested levels had a much greater effect on the gonadosomatic index and female Fulton condition factor than spectral composition and light intensity.The photoperiod had a significant effect on the secretion of sex steroids and melatonin(P<0.05),and a short photoperiod delayed sex steroid and melatonin level increases.The three test factors had no significant effects on the survival rate,specific growth rate,relative weight gain,and male Fulton condition factor(P>0.05).The optimum lighting levels in female and male Atlantic salmon were LD 8:16,455 nm(or 625 nm),8.60 W/m^2;and LD 8:16,8.60 W/m^2,455 nm respectively.These conditions not only delayed gonadal development,but also had no negative effects on Atlantic salmon growth in RAS.These results demonstrate that a combination of spectral composition,photoperiod and light intensity is effective at delaying the gonadal development of both male and female salmon in RAS.展开更多
The study was made by observing the annual change of the gonadal development of amphioxus in Xiamen cohtinuously for two years from November, 1986 to November, 1988. We determined the gonadal diameter, gonadosomatic i...The study was made by observing the annual change of the gonadal development of amphioxus in Xiamen cohtinuously for two years from November, 1986 to November, 1988. We determined the gonadal diameter, gonadosomatic index of each amphioxus, and observed the histological characteristic of the gonadal development of the female and male by cut section, which provided the basis for dividing the stages gonads and the determining level of the gonadal development of amphioxus in each month.展开更多
The brain plays a critical role in controlling reproduction through the hypothalamus-pituitary-gonadal(HPG)axis in vertebrates.Turbot(Scophthalmus maximus)has become an economically important marine fish in Europe and...The brain plays a critical role in controlling reproduction through the hypothalamus-pituitary-gonadal(HPG)axis in vertebrates.Turbot(Scophthalmus maximus)has become an economically important marine fish in Europe and North China.Previous research investigating turbot reproduction has focused on the role of the HPG axis in regulating egg and sperm production.However,the morphology and histology of the organs in the HPG axis have not been studied.In this study,we investigated the morphology and histology of brains in female and male turbot at different stages of gonadal development.The results showed that the brains of both female and male turbot were composed of seven parts that are typical of advanced teleosts:the telencephalon,diencephalon,cerebellum,hypothalamus,pituitary gland,myelencephalon,and olfactory bulbs.The telencephalon was well-developed and contained five distinct lobes,with the contiguous diencephalon at the caudal portion.The torus longitudinales and rostral torus semicircularis of the mesencephalon flattened along the dorsal surface,and the rostral corpus cerebellum was located in the dorsal portion.The actual total brain volume in mature males was significantly greater(p<0.05)than that of females with gonadal development.Notably,the pituitary volume in male turbot significantly increased(p<0.05)from immature to mature stage,but this difference did not occur in females.The data together illustrate a distinct sex difference in the turbot brain during gonadal development,providing insight into their HPG axes.展开更多
The P-element induced wimpy testis(Piwi)proteins,which are associated with PIWI-interacting RNAs(piRNAs),play important roles in meiosis,germ cell division,and germline maintenance.In this study,we identified and char...The P-element induced wimpy testis(Piwi)proteins,which are associated with PIWI-interacting RNAs(piRNAs),play important roles in meiosis,germ cell division,and germline maintenance.In this study,we identified and characterized the Paralichthys olivaceus piwil2 gene,a constituent factor of the piRNA pathways involved in the biogenesis of reproductive development.The biological analysis indicated that piwil2,which contains PAZ and PIWI domains,was highly conserved between teleosts and tetrapods.The piwil2 distribution profile in different tissues confirmed a sexually dimorphic expression pattern,with a higher expression level in testis.In situ hybridization demonstrated that piwil2 was expressed in the oogonia and oocytes of the ovaries as well as in the Sertoli cells and spermatocytes of the testes.Gene piwil2 showed a maternally inherited expression pattern during embryonic development,and was highly expressed during the early embryonic development.Different luciferase reporters were constructed to determine the transcriptional regulatory mechanisms of piwil2.The piwil2 core promoter region was located at−360 bp to−60 bp.Furthermore,some representative sex hormones,including human chorionic gonadotropin,17α-methyltestosterone,and estradiol-17βhad distinct regulatory effects on piwil2.In a summery,these results indicate that piwil2,regulated by sex hormones and transcriptional elements,has vital functions in the reproductive cycle and gonadal development.展开更多
Eyestalk ablation has been widely used in artificial breeding of crustaceans due to its significant promotion effect on gonadal development, which plays a certain role by directly affecting neuroendocrine function of ...Eyestalk ablation has been widely used in artificial breeding of crustaceans due to its significant promotion effect on gonadal development, which plays a certain role by directly affecting neuroendocrine function of X-organ sinus gland (XO-SG) complex in eyestalks. As an important endocrine organ, XO-SG complex of the eyestalk has become a hot issue in crustacean endocrinology. This paper introduced the biological structure and physiological functions of XO-SG complex and summarized the molecular mechanism of eyestalk neuroendocrine, which provided theoretical references for further revealing the regulatory mechanism of eyestalk neuroendocrine system.展开更多
lnterspecific hybridization can generate heterosis, which is proven to be a useful tool in selective breeding programs for oyster culture. Crassostrea angulata and C. ariakensis are two important economic shellfish sp...lnterspecific hybridization can generate heterosis, which is proven to be a useful tool in selective breeding programs for oyster culture. Crassostrea angulata and C. ariakensis are two important economic shellfish species in China. We conducted 2 × 2 reciprocal crosses to determine whether these two species can cross-fertilize and their hybrids can hatch, survive and perform hetero- sis. Fertilization was found symmetrical without delay. The rate of fertilization success of C. angulata ♀× C. ariakensis ♂ was lower than that of C. ariakensis ♀ x C. angulata ♂, and the success rate of both hybridizations was lower than that of two intraspecific crosses each. During the planktonic period, survival rate of the progeny was lower in the hybrid crosses than in the intraspecific crosses. On day 360, mean shell height of the progeny of C. angulata ♀ x C. angulata ♂ was highest, which was followed by that of C. angulata ♀ × C. ariakensis ♂, C. ariakensis ♀x C. ariakensis ♂ and C. ariakensis ♀× C. angulata ♂ in a descending order. Mor- phology of adults produced by the hybrid crosses was similar to that of C. angulata. Both hybrids underwent normal gonad devel- opment and produced mature gametes in the mating season. This study provided new insights into the quantitative traits in interspeci- fic crosses of Crassostrea species, thus being of guidance value for selective breeding of oyster.展开更多
The limited knowledge about the relationships between environmental factors and the maturation and reproductive seasonality of nemerteans is mostly obtained from field studies, and in many cases is conjectural. Few sp...The limited knowledge about the relationships between environmental factors and the maturation and reproductive seasonality of nemerteans is mostly obtained from field studies, and in many cases is conjectural. Few species have been studied under well-controlled laboratory conditions. In this work, the effects of temperature and photoperiod on gonad development and spawning of Cephalothrix hongkongiensis were observed by rearing worms under different temperatures and photoperiods. Worms reared at 4~C and 6~C showed no growth or gonadal development, and all died within 109 days. At 8~C and 12~C, gonads could be seen from 90 days to the termination of the 360-day experiment, but no spawning was observed. Worms maintained at 16, 24, and 28~C showed both gonadal development and spawning, and matured faster at higher temperatures. Under a fixed temperature (16℃), photoperiod did not have any significant impact on maturation and spawning. It is likely that temperature plays a major role in regulating the maturation and reproductive cycle of C. hongkongiensis.展开更多
[Objectives] This study was conducted to study early reproduction techniques of yellow catfish(Pelteobagrus fulvidraco) in Jianghan Plain. [Methods] Parents of P. fulvidraco were cultured by the methods of artificial ...[Objectives] This study was conducted to study early reproduction techniques of yellow catfish(Pelteobagrus fulvidraco) in Jianghan Plain. [Methods] Parents of P. fulvidraco were cultured by the methods of artificial temperature control and nutrition enhancement. [Results] After culture, the body weight, gonad weight, maturity coefficient and egg diameter of P. fulvidraco increased gradually. Up to April 30, the gonad weight of the female parents of P. fulvidraco cultured in greenhouses was significantly higher than that of the parents under natural conditions(P<0.05), 54% higher than that of the parents naturally cultured at the same period;the maturity coefficient of the parents cultured under strengthened conditions was also significantly higher than that of the parents under natural conditions at the same period(P<0.05);and the ovaries of the strengthened parents were orange yellow and full of eggs, and the number of eggs per fish was relatively high. In early May, the parents cultured under strengthened conditions were induced to spawn artificially. The average induced spawning rate and fertilization rate reached 86.7% and 71.6%, respectively, reaching the respective normal level. The gonad maturity of P. fulvidraco cultured under strengthened conditions was 15 d earlier than that under natural conditions, resulting in mass production of early-propagated larvae of P. fulvidraco. [Conclusions] In Jianghan plain area, artificial propagation can be achieved in early May by means of artificial temperature control and strengthened culture, which is 20 d ahead of natural conditions.展开更多
This study analyzed the tissue indices,proximate composition,fatty acid and amino acid composition of edible tissues of male E.sinensis under three feeding modes(formulated diets(FD),natural diets(ND),and traditional ...This study analyzed the tissue indices,proximate composition,fatty acid and amino acid composition of edible tissues of male E.sinensis under three feeding modes(formulated diets(FD),natural diets(ND),and traditional diets(TD)).The results showed that different feeding modes had no impacts on the overall gonadal development,as no significant difference was found in gonadsomatic index among three treatments.For edible yield,three modes all had similar levels of the meat yield,hepatosomatic index,and total edible yield.Although different feeding modes did not affect the individual edible yield and gonadal development,significant differences were detected in the nutritional composition of males from three modes.For proximate composition,significant differences were found in the total lipids of gonads and the carbohydrate of hepatopancreas and meat.For fatty acids,crabs from ND had a higher proportion of monounsaturated fatty acids.In gonads and hepatopancreas,FD had a higher proportion of long-chain polyunsaturated fatty acids.For amino acids,FD had higher amino acid contents,while ND had the lowest.Except tryptophan,the essential amino acids scores of the meat were all greater than 100.As there was no significant difference on meat quality and meat yields between three feeding modes,this study suggests that the formulated diet could replace the natural diet and traditional diet towards sustainable crab farming in future.展开更多
Pod1 is a member of the basic helix-loop-helix(bHLH) family of transcription factors that have been implicated in the regulation of sexual differentiation and gonadal development in mammals.However,to date,little is k...Pod1 is a member of the basic helix-loop-helix(bHLH) family of transcription factors that have been implicated in the regulation of sexual differentiation and gonadal development in mammals.However,to date,little is known about the role of Pod1 in nonmammalian vertebrate gonadogenesis.We cloned and characterized the Pod1 gene from tilapia.The tilapia Pod1 gene contains an open reading frame(ORF) of 525 nucleotides which potentially codes for a protein with 174 amino acids.Sequence alignment revealed that the deduced tilapia protein sequence shared high homology(79.5% to 90.5%) with the Pod1 sequences of other vertebrates.The tissue distribution of Pod1 revealed by RT-PCR showed that it had varied expression patterns in adult tilapia.In situ hybridization was performed to examine the temporal and spatial expression patterns of Pod1 during tilapia sexual differentiation and gonadal development.In the undifferentiated gonad,Pod1 was expressed in the somatic cells of both sexes.Subsequently,Pod1 expression in tilapia persisted in differentiated juvenile and adult ovary and testis.Our data indicate for the first time that Pod1 is not only necessary for the onset of sexual differentiation,but also plays an important role in gonadal development in the teleost.展开更多
Vast stretches of open water bodies are gradually becoming hypoxic as a result of depletion of oxygen levels mainly due to various human anthropogenic activities.This problem of hypoxic stress on the fish population i...Vast stretches of open water bodies are gradually becoming hypoxic as a result of depletion of oxygen levels mainly due to various human anthropogenic activities.This problem of hypoxic stress on the fish population is likely to be exacerbated soon since the aquatic hypoxic environment is continuously spreading over vast areas worldwide.In recent years,various harmful effects of hypoxia to bony fishes have been reported,such as the restriction of energy-consuming metabolic processes,arrest of the growth of ovary and testes that are associated with endocrine disruption,loss of sperm and egg quality,inhibition of fertilization,hatching success,and also the reduction of larval survivability,thereby impairment of overall reproductive and developmental processes in fish.Disruption of the brain-pituitary-gonad axis,and certain enzymes related to steroidogenesis and vitellogenesis in fish have also been reported as the primary targets for an endocrine malfunction during hypoxia.Hypoxia-sensitive downregulation of key genes responsible for controlling sex hormones’synthesis has been documented in certain bony fishes.Further,continuous exposure to hypoxia was reported to induce early expression of pro-apoptotic/tumor suppressor p53 genes,thereby causing immense cell death in hypoxic embryos.However,the cellular responses to long-term hypoxia exposure and the degree of reproductive impairments in bony fishes are still not adequate to figure out the actual underlying mechanisms.The present review intends to highlight the current knowledge about the detrimental impact of chronic/acute hypoxia at different stages of fish reproduction and the associated underlying molecular mechanisms.展开更多
The Yangtze River and its branches are important habitats for the Japanese Eel(Anguilla japonica),however,there are few data on gonadal development and silvering indices of eels during the downstream spawning migratio...The Yangtze River and its branches are important habitats for the Japanese Eel(Anguilla japonica),however,there are few data on gonadal development and silvering indices of eels during the downstream spawning migration.This study investigates gonadal development in 121 Japanese eels caught downstream from the Jingjiang Reach of the Yangtze River in October 2012.We found that in females the ovaries of most of the out-migrating population developed earlier than the testes in males,that is,the ovaries reached stage 3(F3)or early stage 4(eF4),while the testes were at stage 2(M2)or stage 3(M3).Gonadal development in eels collected in 2012 was earlier than that of samples caught from the same region in 2007e2008 and from the Pearl River Estuary in 1972e1973.The average age,body size and gonadal-somatic index of females were significantly greater than those in males.For both females and males,there were no significant differences between the two stages of gonadal development in any of the morphological indices,which indicates that gonadal development of the Japanese Eel is independent of body size.These results help us to understand the spawning population of Japanese Eels in the Yangtze River.展开更多
文摘A twelve week experiment was conducted to compare the effects of diets with plant-based and animal-based ingredients on growth and gonad development of Clarias gariepinus. One hundred and 12 sub-adult C. gariepinus with an average weight of 205 ×5.09 g, were stocked in six concrete tanks (9 × 4 × 2 m3) containing 20 fish each. Experiment had 3 replicates and animals fed daily at 5% body weights. There was no significant difference (P 〈 0.05) in proximate compositions of the two experimental feeds and controls. Fecundity, gonad weight and gonasomatic index were higher in fish fed diet 13 than A and C. Similarly, growth indices were higher in fish fed diet B than in A and C. Histology of gonads showed a faster development of oocytes of eggs in fish fed animal-based ingredients than plant-based and combined plant and animal diets. Although there were slight differences in growth parameters and gonad development in favor of feed with animal-based ingredients, plant-based feed compared favorably in the growth and gonad development of C. gariepinus. Plant-based ingredients are recommended on the basis of affordability and availability as substitute for animal-based ingredients in C. gariepinus feed.
基金supported by the National Key R&D Program of China (No. 2018YFD0901205)
文摘The factor in the germline alpha(figla), as a member of the basic helix-loop-helix family, has been reported to be involved in ovary development in mammals and teleosts. However, the regulatory mechanisms of figla in teleosts remain unclear. Here,figla in P. olivaceus(Pofigla) was characterized with encoding a 202 amino acid protein that contains a conserved basic region and helix-loop-helix(HLH) domain. Amino acids alignment and synteny analysis revealed that Pofigla was conserved with the orthologous gene sequences in other vertebrates. The results of qRT-PCR showed Pofigla was maternally inherited during embryonic development. For tissue distribution, Pofigla showed a sexually dimorphic gene expression in the gonad of different genders, with a higher expression in ovary than in testis. In situ hybridization(ISH) results demonstrated Pofigla was specifically expressed in germ cells including oocytes, spermatogonia and spermatocytes. By screening and analyzing two proximal regions(-2966/-2126 and-772/-444) with high promoter activity, we found SOX5, LEF1, FOXP1 and GATA1 may play important roles in the transcriptional regulation of Pofigla. Furthermore, we observed the co-localization between Figla and LEF1 in HEK 293T cells. And the significant up-regulation effect of the canonical Wnt signaling pathway on the expression of Pofigla was found in cultured ovarian cells. This study provided the first evidence that figla not only has an important function in ovary development, but also plays some potential roles in testis development and/or male germ cell differentiation during early testis development in P. olivaceus. The results provide valuable reference in exploring the regulatory network of figla in teleost.
基金Supported by the Zhejiang Provincial Department of Science and Technology,“Pioneer”and“Leading Goose”R&D Program of Zhejiang (No.2022C02040)the Science and Technology Bureau of Zhoushan (No.2022C41021)。
文摘The sea urchin Heliocidaris crassispina has northern expanded in geographic range to Toga Bay,Oga Peninsula in the Sea of Japan due to the global warming.To demonstrate the gonad traits and age structure of H.crassispina in the central range and compare the difference with those in northern extended range,we collected 100 H.crassispina individuals from a barren off Shitsumi,Fukui(central range),in August 2018.Their growth,gonad traits(size,development and color),and sex ratio were investigated and compared with those in Toga Bay,in August 2014(extended range).The successive 2012–2016 year classes of H.crassispina indicated successive juvenile recruitment in the central range,as found in the extended range.The individuals at three years old in central range were obviously larger than those in the extended range,showing large test diameter and body weight,possibly due to the higher temperature in central range than that in northern extended range.In addition,a balanced sex ratio in the central range was found,in contrast to the female-skewed sex ratio found in the extended range.Gonadal development was sex-and site-dependent.The testicular development in the central range was not only delayed in comparison to ovarian development,but also less delayed than those in the extended range,which possibly attribute to the higher water temperature in the central range.A significantly lower male gonad index and L*(lightness)value was recorded in central ranges compared to that in extended range,possibly due to the releasement of sperm of H.crassispina in central ranges.
基金Supported by the National Key Technologies R&D Program of China(No.2011BAD13B04)the Knowledge Innovation Program of Chinese Academy of Sciences(No.KZCX2-EW-Q212)+2 种基金the Public Service Sectors(Agriculture)Special Project(No.201003024)the Earmarked Fund for Modern Agro-Industry Technology Research Systemthe Shandong Program for Development of Science and Technology(No.2013GHY11514)
文摘Artificial lighting regimes have been successfully used to inhibit sexual maturity of Atlantic salmon in confinement.However,when these operations are applied in commercial recirculating aquaculture systems(RAS) using standard lighting technology,sexual maturation is not suppressed.In this study,an L_9(3~3) orthogonal design was used to determine the effects of three factors(spectral composition,photoperiod,and light intensity) on the gonadal development of Atlantic salmon in RAS.We demonstrated that the photoperiod at the tested levels had a much greater effect on the gonadosomatic index and female Fulton condition factor than spectral composition and light intensity.The photoperiod had a significant effect on the secretion of sex steroids and melatonin(P<0.05),and a short photoperiod delayed sex steroid and melatonin level increases.The three test factors had no significant effects on the survival rate,specific growth rate,relative weight gain,and male Fulton condition factor(P>0.05).The optimum lighting levels in female and male Atlantic salmon were LD 8:16,455 nm(or 625 nm),8.60 W/m^2;and LD 8:16,8.60 W/m^2,455 nm respectively.These conditions not only delayed gonadal development,but also had no negative effects on Atlantic salmon growth in RAS.These results demonstrate that a combination of spectral composition,photoperiod and light intensity is effective at delaying the gonadal development of both male and female salmon in RAS.
文摘The study was made by observing the annual change of the gonadal development of amphioxus in Xiamen cohtinuously for two years from November, 1986 to November, 1988. We determined the gonadal diameter, gonadosomatic index of each amphioxus, and observed the histological characteristic of the gonadal development of the female and male by cut section, which provided the basis for dividing the stages gonads and the determining level of the gonadal development of amphioxus in each month.
基金The National Natural Science Foundation of China under contract Nos 31802319,31972784,31802269the Natural Science Foundation of Shandong Province under contract No.ZR2018BC053+1 种基金the Agricultural Application Technology Innovation Project of Shandong Province under contract No.SD2019YY006the Advanced Talents Foundation of Qingdao Agricultural University under contract Nos 6631119055,6631119032.
文摘The brain plays a critical role in controlling reproduction through the hypothalamus-pituitary-gonadal(HPG)axis in vertebrates.Turbot(Scophthalmus maximus)has become an economically important marine fish in Europe and North China.Previous research investigating turbot reproduction has focused on the role of the HPG axis in regulating egg and sperm production.However,the morphology and histology of the organs in the HPG axis have not been studied.In this study,we investigated the morphology and histology of brains in female and male turbot at different stages of gonadal development.The results showed that the brains of both female and male turbot were composed of seven parts that are typical of advanced teleosts:the telencephalon,diencephalon,cerebellum,hypothalamus,pituitary gland,myelencephalon,and olfactory bulbs.The telencephalon was well-developed and contained five distinct lobes,with the contiguous diencephalon at the caudal portion.The torus longitudinales and rostral torus semicircularis of the mesencephalon flattened along the dorsal surface,and the rostral corpus cerebellum was located in the dorsal portion.The actual total brain volume in mature males was significantly greater(p<0.05)than that of females with gonadal development.Notably,the pituitary volume in male turbot significantly increased(p<0.05)from immature to mature stage,but this difference did not occur in females.The data together illustrate a distinct sex difference in the turbot brain during gonadal development,providing insight into their HPG axes.
基金This study was supported by the National Natural Science Foundation of China(No.31672646)the Natural Science Foundation of Shandong Province(No.ZR 2017MC072).
文摘The P-element induced wimpy testis(Piwi)proteins,which are associated with PIWI-interacting RNAs(piRNAs),play important roles in meiosis,germ cell division,and germline maintenance.In this study,we identified and characterized the Paralichthys olivaceus piwil2 gene,a constituent factor of the piRNA pathways involved in the biogenesis of reproductive development.The biological analysis indicated that piwil2,which contains PAZ and PIWI domains,was highly conserved between teleosts and tetrapods.The piwil2 distribution profile in different tissues confirmed a sexually dimorphic expression pattern,with a higher expression level in testis.In situ hybridization demonstrated that piwil2 was expressed in the oogonia and oocytes of the ovaries as well as in the Sertoli cells and spermatocytes of the testes.Gene piwil2 showed a maternally inherited expression pattern during embryonic development,and was highly expressed during the early embryonic development.Different luciferase reporters were constructed to determine the transcriptional regulatory mechanisms of piwil2.The piwil2 core promoter region was located at−360 bp to−60 bp.Furthermore,some representative sex hormones,including human chorionic gonadotropin,17α-methyltestosterone,and estradiol-17βhad distinct regulatory effects on piwil2.In a summery,these results indicate that piwil2,regulated by sex hormones and transcriptional elements,has vital functions in the reproductive cycle and gonadal development.
基金Supported by Special Fund for Agro-scientific Research in the Public Interest(201003070)Youth Fund from Natural Science Foundation of Jiangsu Province(BK2012090)Central Public-interest Scientific Institution Basal Research Fund(2013JBFM09)
文摘Eyestalk ablation has been widely used in artificial breeding of crustaceans due to its significant promotion effect on gonadal development, which plays a certain role by directly affecting neuroendocrine function of X-organ sinus gland (XO-SG) complex in eyestalks. As an important endocrine organ, XO-SG complex of the eyestalk has become a hot issue in crustacean endocrinology. This paper introduced the biological structure and physiological functions of XO-SG complex and summarized the molecular mechanism of eyestalk neuroendocrine, which provided theoretical references for further revealing the regulatory mechanism of eyestalk neuroendocrine system.
基金supported by the National Natural Science Foundation of China(Grant No.31172403)the National Key Basic Research Development Planning Project(Grant No.2010CB126406)
文摘lnterspecific hybridization can generate heterosis, which is proven to be a useful tool in selective breeding programs for oyster culture. Crassostrea angulata and C. ariakensis are two important economic shellfish species in China. We conducted 2 × 2 reciprocal crosses to determine whether these two species can cross-fertilize and their hybrids can hatch, survive and perform hetero- sis. Fertilization was found symmetrical without delay. The rate of fertilization success of C. angulata ♀× C. ariakensis ♂ was lower than that of C. ariakensis ♀ x C. angulata ♂, and the success rate of both hybridizations was lower than that of two intraspecific crosses each. During the planktonic period, survival rate of the progeny was lower in the hybrid crosses than in the intraspecific crosses. On day 360, mean shell height of the progeny of C. angulata ♀ x C. angulata ♂ was highest, which was followed by that of C. angulata ♀ × C. ariakensis ♂, C. ariakensis ♀x C. ariakensis ♂ and C. ariakensis ♀× C. angulata ♂ in a descending order. Mor- phology of adults produced by the hybrid crosses was similar to that of C. angulata. Both hybrids underwent normal gonad devel- opment and produced mature gametes in the mating season. This study provided new insights into the quantitative traits in interspeci- fic crosses of Crassostrea species, thus being of guidance value for selective breeding of oyster.
基金Supported by the National Natural Science Foundation of China(Nos.30970333,31172046)
文摘The limited knowledge about the relationships between environmental factors and the maturation and reproductive seasonality of nemerteans is mostly obtained from field studies, and in many cases is conjectural. Few species have been studied under well-controlled laboratory conditions. In this work, the effects of temperature and photoperiod on gonad development and spawning of Cephalothrix hongkongiensis were observed by rearing worms under different temperatures and photoperiods. Worms reared at 4~C and 6~C showed no growth or gonadal development, and all died within 109 days. At 8~C and 12~C, gonads could be seen from 90 days to the termination of the 360-day experiment, but no spawning was observed. Worms maintained at 16, 24, and 28~C showed both gonadal development and spawning, and matured faster at higher temperatures. Under a fixed temperature (16℃), photoperiod did not have any significant impact on maturation and spawning. It is likely that temperature plays a major role in regulating the maturation and reproductive cycle of C. hongkongiensis.
基金Supported by The Technological Innovation Special Project of Hubei Province(2018ABA104)
文摘[Objectives] This study was conducted to study early reproduction techniques of yellow catfish(Pelteobagrus fulvidraco) in Jianghan Plain. [Methods] Parents of P. fulvidraco were cultured by the methods of artificial temperature control and nutrition enhancement. [Results] After culture, the body weight, gonad weight, maturity coefficient and egg diameter of P. fulvidraco increased gradually. Up to April 30, the gonad weight of the female parents of P. fulvidraco cultured in greenhouses was significantly higher than that of the parents under natural conditions(P<0.05), 54% higher than that of the parents naturally cultured at the same period;the maturity coefficient of the parents cultured under strengthened conditions was also significantly higher than that of the parents under natural conditions at the same period(P<0.05);and the ovaries of the strengthened parents were orange yellow and full of eggs, and the number of eggs per fish was relatively high. In early May, the parents cultured under strengthened conditions were induced to spawn artificially. The average induced spawning rate and fertilization rate reached 86.7% and 71.6%, respectively, reaching the respective normal level. The gonad maturity of P. fulvidraco cultured under strengthened conditions was 15 d earlier than that under natural conditions, resulting in mass production of early-propagated larvae of P. fulvidraco. [Conclusions] In Jianghan plain area, artificial propagation can be achieved in early May by means of artificial temperature control and strengthened culture, which is 20 d ahead of natural conditions.
基金This study was funded by a general project(No.31572630)from the Natural Science Foundation of Chinathe Special Fund(CARS-48)of Chinese Agriculture Research System-48 from Ministry of Agriculture and Rural affairs of China+3 种基金a standard development project(No.125C0701)for mitten crab quality and classification from Ministry of Agriculture and Rural affairs of ChinaInfrastructure costs were supported by the construction and improvement project(No.A1-2801-18-1003)for high level university in Shanghai from Shanghai Education CommissionShanghai talents development fund for the young scientists(No.2018100)from Shanghai Municipal Human ResourcesSocial Security Bureau and the innovation and extension project(No.Y2017-4)of Science and technology from Jiangsu ocean and Fisheries Bureau.
文摘This study analyzed the tissue indices,proximate composition,fatty acid and amino acid composition of edible tissues of male E.sinensis under three feeding modes(formulated diets(FD),natural diets(ND),and traditional diets(TD)).The results showed that different feeding modes had no impacts on the overall gonadal development,as no significant difference was found in gonadsomatic index among three treatments.For edible yield,three modes all had similar levels of the meat yield,hepatosomatic index,and total edible yield.Although different feeding modes did not affect the individual edible yield and gonadal development,significant differences were detected in the nutritional composition of males from three modes.For proximate composition,significant differences were found in the total lipids of gonads and the carbohydrate of hepatopancreas and meat.For fatty acids,crabs from ND had a higher proportion of monounsaturated fatty acids.In gonads and hepatopancreas,FD had a higher proportion of long-chain polyunsaturated fatty acids.For amino acids,FD had higher amino acid contents,while ND had the lowest.Except tryptophan,the essential amino acids scores of the meat were all greater than 100.As there was no significant difference on meat quality and meat yields between three feeding modes,this study suggests that the formulated diet could replace the natural diet and traditional diet towards sustainable crab farming in future.
基金supported by the National Natural Science Foundation of China (Grant No. 31072199)a program of the Japan Society for the Promotion of Science,Japan
文摘Pod1 is a member of the basic helix-loop-helix(bHLH) family of transcription factors that have been implicated in the regulation of sexual differentiation and gonadal development in mammals.However,to date,little is known about the role of Pod1 in nonmammalian vertebrate gonadogenesis.We cloned and characterized the Pod1 gene from tilapia.The tilapia Pod1 gene contains an open reading frame(ORF) of 525 nucleotides which potentially codes for a protein with 174 amino acids.Sequence alignment revealed that the deduced tilapia protein sequence shared high homology(79.5% to 90.5%) with the Pod1 sequences of other vertebrates.The tissue distribution of Pod1 revealed by RT-PCR showed that it had varied expression patterns in adult tilapia.In situ hybridization was performed to examine the temporal and spatial expression patterns of Pod1 during tilapia sexual differentiation and gonadal development.In the undifferentiated gonad,Pod1 was expressed in the somatic cells of both sexes.Subsequently,Pod1 expression in tilapia persisted in differentiated juvenile and adult ovary and testis.Our data indicate for the first time that Pod1 is not only necessary for the onset of sexual differentiation,but also plays an important role in gonadal development in the teleost.
基金the Science and Engineering Research Board,New Delhi(CRG/2021/005588).
文摘Vast stretches of open water bodies are gradually becoming hypoxic as a result of depletion of oxygen levels mainly due to various human anthropogenic activities.This problem of hypoxic stress on the fish population is likely to be exacerbated soon since the aquatic hypoxic environment is continuously spreading over vast areas worldwide.In recent years,various harmful effects of hypoxia to bony fishes have been reported,such as the restriction of energy-consuming metabolic processes,arrest of the growth of ovary and testes that are associated with endocrine disruption,loss of sperm and egg quality,inhibition of fertilization,hatching success,and also the reduction of larval survivability,thereby impairment of overall reproductive and developmental processes in fish.Disruption of the brain-pituitary-gonad axis,and certain enzymes related to steroidogenesis and vitellogenesis in fish have also been reported as the primary targets for an endocrine malfunction during hypoxia.Hypoxia-sensitive downregulation of key genes responsible for controlling sex hormones’synthesis has been documented in certain bony fishes.Further,continuous exposure to hypoxia was reported to induce early expression of pro-apoptotic/tumor suppressor p53 genes,thereby causing immense cell death in hypoxic embryos.However,the cellular responses to long-term hypoxia exposure and the degree of reproductive impairments in bony fishes are still not adequate to figure out the actual underlying mechanisms.The present review intends to highlight the current knowledge about the detrimental impact of chronic/acute hypoxia at different stages of fish reproduction and the associated underlying molecular mechanisms.
基金This study was supported by the National Natural Science Foundation of China(No.31201995)the Shanghai Municipal Agricultural Commission(No.20132-2)+1 种基金the Shanghai Municipal Science and Technology Commission of Chongming(No.13231203504)the Open Foundation of Engineering Research Centre of Modern Industrial Technology for Eels,Ministry of Education,China(No.RE201501).
文摘The Yangtze River and its branches are important habitats for the Japanese Eel(Anguilla japonica),however,there are few data on gonadal development and silvering indices of eels during the downstream spawning migration.This study investigates gonadal development in 121 Japanese eels caught downstream from the Jingjiang Reach of the Yangtze River in October 2012.We found that in females the ovaries of most of the out-migrating population developed earlier than the testes in males,that is,the ovaries reached stage 3(F3)or early stage 4(eF4),while the testes were at stage 2(M2)or stage 3(M3).Gonadal development in eels collected in 2012 was earlier than that of samples caught from the same region in 2007e2008 and from the Pearl River Estuary in 1972e1973.The average age,body size and gonadal-somatic index of females were significantly greater than those in males.For both females and males,there were no significant differences between the two stages of gonadal development in any of the morphological indices,which indicates that gonadal development of the Japanese Eel is independent of body size.These results help us to understand the spawning population of Japanese Eels in the Yangtze River.