Egg Transport Research Articles

Intrinsic pacemaker activity and propulsive forces provided by the myosalpinx are necessary for egg and embryo transport in the oviduct.

Oviducts or fallopian tubes are essential for normal fertilization and development of the early embryo; however, their functions are still poorly understood. Oviducts facilitate several physiological processes including (i) transport of the ovum from the ovary to the site of fertilization [1], (ii) aiding the transport of spermatozoa to the site of fertilization [2], (iii) providing a suitable environment for ova and protection from mechanical damage [3], (iv) the maintenance of viability of ova [3], and (v) timely transport of the early embryo to the uterus for implantation [4]. Pathophysiological conditions that disrupt the normal functions of the oviduct often lead to serious health problems, including infertility, ectopic pregnancy, failed early embryonic development, and subsequent loss of embryos. Thus, the oviduct is essential for normal female fertility. In a recent study by Bianchi et al. [5], the authors...

Connectivity Analysis Applied to Mesoscale Eddies in the Western Mediterranean Basin

The Western Mediterranean basin (WMED) is characterized by the presence of energetic and dynamic mesoscale cyclonic and anticyclonic eddies. They mainly originate along the Algerian and the Northern currents and have a large influence on the basin circulation. Eddies can last for months, with longer lifetimes associated with the anticyclones, which can move far from their areas of origin. As they partially isolate and transfer water masses, they also have an impact on water properties (physical, chemical and biological), pollutant’s dispersion and transport of eggs, larvae and planktonic organisms. In this study, a connectivity analysis method is applied to the anticyclonic eddies (AEs) identified by an automated hybrid detection and tracking algorithm south of 42°N in the WMED. The same methodology is also applied to the trajectories of Lagrangian surface drifters available in the study area. The purpose is to highlight the connections between different areas of the basin linked to eddy activities in addition to the connectivity due to the mean surface circulation. Drifter data analysis showed that all the WMED sub-basins are strongly interconnected, with the mean surface circulation allowing a shortcut connection among many areas of the basin. The connectivity analysis of the AEs tracks shows that although AEs are ubiquitous in the WMED, their connectivity is limited to well-defined regions, depending on their origin location. Three main regions: the south-western, the south-eastern and the northern parts of the basin are characterized by AEs recirculation, with sporadic export of eddies to the other WMED zones.

The Impact of Sea‐Ice Drift and Ocean Circulation on Dispersal of Toothfish Eggs and Juveniles in the Ross Gyre and Amundsen Sea

AbstractKnowledge about the early life history of Antarctic toothfish (Dissostichus mawsoni) is still incomplete, particularly on the spatial and temporal extent of spawning and the subsequent transport of eggs, larvae, and juveniles from the offshore spawning areas to the continental shelf. This study used a high‐resolution hydrodynamic model to investigate the impact of ocean circulation and sea‐ice drift on the dispersal of eggs, larvae, and juvenile Antarctic toothfish. The virtual eggs were released on seamounts of the Pacific‐Antarctic ridge in the Ross Gyre and advected using hydrodynamical model data. Particles were seeded annually over the years 2002–2016 and tracked for 3 years after their release. Recruitment success was evaluated based on the number of juveniles that reached known coastal recruitment areas, between the eastern Ross and Amundsen Seas, within 3 years. Sensitivities to certain juvenile behaviors were explored and showed that recruitment success was reduced by around 70% if juveniles drifted with sea‐ice during the second winter season as this carried them into the open ocean away from the shelf region. Recruitment success increased during the second winter season if juveniles were entrained in the Ross Gyre circulation or if they actively swam toward the shelf. These modeling results suggest that the ecological advantage of sea‐ice association in the early life cycle of toothfish diminishes as they grow, promoting a behavior change during their second winter.

Modeling the egg and larval transport pathways of the Antarctic toothfish (Dissostichus mawsoni) in the East Antarctic region: New insights into successful transport connections

AbstractThe Antarctic toothfish (Dissostichus mawsoni) is an important fishery species widely distributed in the Southern Ocean, especially in areas covered by sea ice. Understanding fish distributions and life cycles, including the transport and survival of eggs and larvae, is essential for the assessment and sustainable management of the fishery. However, owing to difficulties with in situ winter observations, information on the early life stages of D. mawsoni is lacking. Here, we investigated the transport pathways of fish eggs and larvae through a particle tracking study, using satellite‐derived ocean surface velocities in the East Antarctic region, which includes important D. mawsoni habitats and exploratory fisheries. Our results indicate that particles released from continental slopes are more likely to be successfully transported to suitable settlement grounds than those released from the BANZARE Bank (the southern region of the Kerguelen Plateau), which is situated further north and has been hypothesized to be a potential spawning ground for D. mawsoni. This study demonstrates successful source–settlement connections in relation to ocean recirculation and suggests important settlement regions for D. mawsoni larvae in the East Antarctic region.

RNA sequencing-based analysis of the magnum tissues revealed the novel genes and biological pathways involved in the egg-white formation in the laying hen

BackgroundThe mechanism of egg formation in the oviduct of laying hens is tightly controlled; each segment of the oviduct contributes a unique component of the egg. Several genes/proteins are involved in the synthesis of a completely healthy egg. This implies a time- and tissue-specific expression of genes and proteins in the different oviductal segments. We used hens at different physiological stages and time points to understand the transcriptional regulation of egg-white (albumen) synthesis and secretion onto the eggs in the magnum of laying hens. This study used Next-Generation Sequencing and quantitative real-time PCR (qPCR) to detect the novel genes and the cognate biological pathways that regulate the major events during the albumen formation.ResultsMagnum tissues collected from laying (n = 5 each at 3 h post-ovulation, p.o. and 15–20 h p.o.), non-laying (n = 4), and molting (n = 5) hens were used for differential gene expression analyses. A total of 540 genes (152 upregulated and 388 down-regulated) were differentially expressed at 3 h p.o. in the magnum of laying hens. Kyoto Encyclopedia of Genes and Genomes pathways analysis of the 152 upregulated genes revealed that glycine, serine, and threonine metabolism was the most-enriched biological pathway. Furthermore, the top two most enriched keywords for the upregulated genes were amino-acid biosynthesis and proteases. Nine candidate genes associated with albumen formation were validated with qPCR to have differential expression in laying, non-laying, and molting hens. Proteases such as TMPRSS9, CAPN2, MMP1, and MMP9 (protein maturation, ECM degradation, and angiogenesis); enzymes such as PSPH, PHGDH, and PSAT1 (amino-acid biosynthesis); RLN3, ACE, and REN (albumen synthesis, secretion and egg transport); and AVD, AvBD11, and GPX3 (antimicrobial and antioxidants) were recognized as essential molecules linked to albumen deposition in the magnum.ConclusionsThis study revealed some novel genes that participate in the signaling pathways for egg-white synthesis and secretion along with some well-known functional genes. These findings help to understand the mechanisms involved in albumen biosynthesis.

A lateral oviduct secreted protein plays a vital role for egg movement through the female reproductive tract in the brown planthopper

The oviduct serves as a delivery tube for mature eggs ovulated from ovaries to egg-laying sites. Oviduct secreted components play important roles in ovulation and fertilization in mammals, however, no oviduct secreted protein has been characterized in an insect to date. Here, we identified a gene highly expressed in the lateral oviduct of the adult females in the brown planthopper (BPH), Nilaparvata lugens, the most destructive rice insect pest. Western blotting and immunofluorescence analyses revealed that the gene encodes a protein that is specifically expressed in the lateral oviduct as a component of the gel-like material secreted by the oviduct epithelial cells into the lumen of the swollen part of the lateral oviducts. The protein was tentatively named N. lugens oviduct secreted protein (Nlodsp). RNA interference (RNAi) against NlOdsp transcripts caused a failure of the lateral oviducts to deliver oocytes to the common oviduct that was, by consequence, plugged by 1–2 oocytes. Moreover, although oocytes in the Nlodsp-deficient ovariole were not released to the oviduct, they continued to develop, finally resulting in the presence of several matured oocytes in an ovariole. These defects evidently declined female fecundity. Together, our results demonstrate that NlOdsp plays an essential role in egg transport through the oviduct during ovulation. This work deepens our understanding of insect reproductive system and provides a potential target gene for RNAi-based insect pest control.

Identification and localization of a gonadotropin-releasing hormone-related neuropeptide in Biomphalaria, an intermediate host for schistosomiasis.

Freshwater snails of the genus Biomphalaria serve as obligatory hosts for the digenetic trematode Schistosoma mansoni, the causative agent for the most widespread form of intestinal schistosomiasis. Within Biomphalaria, S. mansoni larvae multiply and transform into the cercariae form that can infect humans. Trematode development and proliferation is thought to be facilitated by modifications of host behavior and physiological processes, including a reduction of reproduction known as "parasitic castration." As neuropeptides participate in the control of reproduction across phylogeny, a neural transcriptomics approach was undertaken to identify peptides that could regulate Biomphalaria reproductive physiology. The present study identified a transcript in Biomphalaria alexandrina that encodes a peptide belonging to the gonadotropin-releasing hormone (GnRH) superfamily. The precursor and the predicted mature peptide, pQIHFTPDWGNN-NH2 (designated Biom-GnRH), share features with peptides identified in other molluscan species, including panpulmonates, opisthobranchs, and cephalopods. An antibody generated against Biom-GnRH labeled neurons in the cerebral, pedal, and visceral ganglia of Biomphalaria glabrata. GnRH-like immunoreactive fiber systems projected to all central ganglia. In the periphery, immunoreactive material was detected in the ovotestis, oviduct, albumen gland, and nidamental gland. As these structures serve crucial roles in the production, transport, nourishment, and encapsulation of eggs, disruption of the GnRH system of Biomphalaria could contribute to reduced reproductive activity in infected snails.

STtech: sampling and transport techniques for Aedes eggs during a sampling campaign in a low‐resource setting

AbstractContainer‐breeding Aedes spp. (Diptera: Culicidae) mosquitoes can be surveilled at low cost using ovitraps. Hence, this method is a preferred monitoring approach of dengue vectors in low‐resource settings. The ovitraps consist of a cup filled with water and an oviposition substrate for female mosquitoes. The attractiveness of the substrates for female mosquitoes can greatly differ due to differences in texture, color, and smell of the materials used. We compare four oviposition substrates, which are all low priced, easy to transport, and easy to purchase, to maximize the success of Aedes egg sampling. Sampled egg material is often reared to adulthood for further taxonomic identification and transported to (international) laboratories for specialized vector research. Here we introduce a transport technique for sampled eggs. In addition, we explored the impact of international transport by means of a bilateral hatching experiment in Nepal, the country of origin, and in Germany, in a laboratory specialized in ecophysiological research. The best low‐cost oviposition substrate for the dengue vectors Aedes albopictus (Skuse) and Aedes aegypti (L.) was found to be a white cotton sheet. The introduced transport technique of sampled eggs is easy to build from laboratory and household materials and ensures good transport conditions (i.e., temperature and relative humidity). Even under good temperature (17.4–31.0 °C) and humidity conditions (58.9–94.2%), hatching success of eggs was found to be reduced after international transport to Germany when compared to the hatching success of eggs in Nepal. We postulate that air pressure during international transport may have reduced the hatching success and strongly recommend pressure‐regulated transport boxes for egg transport via airplane. As the proposed operation procedure is useful in assisting the monitoring of Ae. albopictus and Ae. aegypti in low‐resource settings, Aedes researchers are encouraged to follow it for the sampling and transport of Aedes eggs.

Land slugs in plant nurseries, a potential cause of dispersal in Argentina

Commercial plant nurseries may serve as causes of dispersal of land snails and slugs (native and non-native) through the trade of plants and the related transport of eggs and small individuals that may pass unnoticed. Studies on the possible role of plant nurseries as a potential cause of dispersal of slugs in South America are lacking. To explore the role of garden centers, we collected and identified slugs in 12 commercial nurseries in two cities in the province of Buenos Aires, Argentina. Eight species of slugs were found. Based on our findings we validate the existence of Deroceras laeve and Belocaulus angustipes for Argentina and confirm the existence of Ambigolimax valentianus, which was recently cited for Argentina. We recommend that plant nurseries be regularly monitored given that snail and slug species are accidentally spread through trade in plants. Dataset published through Zenodo (Doi: http://doi.org/10.5281/zenodo.4304621)

Transportation of fertilized eggs and yolk-sac larvae of hilsa shad, Tenualosa ilisha (Hamilton, 1822) in different transportation systems

Hilsa shad, Tenualosa ilisha has received much attention for their conservation through culture. Transportation mechanism of eggs and larvae is one of the major bottlenecks of hilsa culture. The present study aims to find out the best transporting system, stocking density (SD) and early life stages that record maximum survival after transport needed to facilitate hilsa culture. Eggs and yolk-sac larvae (1-h, 10-h and 6-days old) of hilsa, Tenualosa ilisha were transported in different systems (CAFPB, closed air filled polyethylene bag; COFPB, closed oxygen filled polyethylene bag; CAFBPJ, closed air filled big plastic jar; OAH, open aluminium hundi; CAFSPJ, closed air filled small plastic jar; CAFMPJ, closed air filled medium plastic jar) and SD. Egg survival in CAFPB and COFPB was 32.83–84% depending on the transporting system and SD. In CAFPB and COFPB, egg survival was negatively correlated (P < 0.01) with SD. At all SD (100, 300, 500, 700 and 1000 nos. L−1), COFPB showed higher egg survival than in CAFPB. At 100 nos. L−1, egg survival in CAFPB and COFPB was higher (P < 0.05) than that of 300, 700 and 1000 nos. L−1. The best option for egg transportation was COFPB with 100 L−1 SD. The survival of 1-h old yolk-sac larvae at 1000 nos. L−1 was 97.96–99.32% in different transporting systems. The survival of larvae was higher (P < 0.05) in COFPB than that of CAFPB and CAFBPJ and also in CAFPB than that of CAFBPJ. The 10-h old yolk-sac larvae at 100 nos. L−1 in different closed systems (CAFPB, CAFSPJ and CAFMPJ) exhibited significantly (P < 0.05) higher survival (94.44–98%) than that in open system (OAH) with 60.1% survival being unsuitable for transportation. The survival of 6-days old yolk-sac larvae at 50, 100, 200, 300 and 400 nos. L−1 varied between 97 and 99.7% during 2 h of transportation in COFPB. Based on the present study, it is concluded that hilsa eggs and larvae could be transported in closed polyethylene bags filled with oxygen or atmospheric air, the former being the best. Among the eggs and yolk-sac larvae (1-h, 10-h and 6-days old), survival of larvae is much higher (94.44–99.7%) than that of the egg (32.83–84%). The most suitable stage for transportation is 1-h old larvae as they could be transported at high stocking density (1000 nos. L−1) with high survival (97.96–99.32%) in different closed transporting systems (CAFBPJ, CAFPB and COFPB).

Mating induces early transcriptional response in the rat endosalpinx: the role of TNF and RA.

During mating, males provide not only the spermatozoa to fertilize the oocyte but also other stimuli that are essential for initiating and maintaining the reproductive programme in females. In the mammalian oviduct, mating regulates sperm storage, egg transport, fertilization, early embryonic development, and oestradiol metabolism. However, the main molecules underlying these processes are poorly understood. Using microarray analyses, we identified 58 genes that were either induced or repressed by mating in the endosalpinx at 3 h post-stimulus. RT-qPCR confirmed that mating downregulated the expression of the Oas1h and Prim1 genes and upregulated the expression of the Ceacam1, Chad, Chst10, Slc5a3 and Slc26a4 genes. The functional category 'cell-to-cell signalling and interaction' was over-represented in this gene list. Network modelling identified TNF and all-trans retinoic acid (RA) as upstream regulators of the mating-induced transcriptional response, which was confirmed by intraoviductal injection of TNF or RA in unmated rats. It partially mimicked the transcriptional effect of mating in the rat endosalpinx. Furthermore, mating decreased RA levels in oviductal fluid, and RA-receptor-gamma (RARG) exhibited a nuclear location in oviductal epithelium in both unmated and mated rats, indicating RA-RARG transcriptional activity. In conclusion, the early transcriptional response regulated by mating in the rat endosalpinx is mediated by TNF and RA. These signalling molecules regulate a cohort of genes involved in 'cell-to-cell signalling and interactions' and merit further studies to understand the specific processes activated in the endosalpinx to sustain the events that occur in the mammalian oviduct early after mating.

Manejo clínico de DIP / DIPA doença inflamatória pélvica e de repetição: uma revisão narrativa

Objetivo: Revisar sobre o manejo clínico de doença inflamatória pélvica e de repetição (DIP/DIPA). Revisão Bibliográfica: A DIP é uma infecção que se origina no trato genital inferior e que em muitos momentos pode atingir os órgãos do trato genital superior feminino, como o endométrio, tubas uterinas ou ovários. A maior prevalência de faixa etária é em mulheres que se encontram sexualmente ativas entre 15-24 anos de idade. É uma doença que se tratada no início consegue minimizar os prejuízos para a saúde da mulher. Se não tratada, a doença pode causar afetar o transporte dos óvulos e dos espermatozoides, acarretando dificuldades para a mulher engravidar ou contribui para chances de uma gestação ectópica. O tratamento da doença inicialmente é feito com o uso de antibióticos orais e intramusculares, caso a paciente apresente quadro de infecção, faz-se necessário a internação para uso de antibióticos endovenosos, e em alguns casos procedimento cirúrgico sendo preciso estabelecer repouso físico e sexual durante o tratamento. Considerações finais: Por se tratar de uma doença de clínica com variações, e em algumas situações assintomática, preconiza a dificuldade de se diagnosticar no início, para que tenha um tratamento adequado e eficiente a natureza da doença.

Connectivity in early life stages of the southern hake, Merluccius australis, in northern Chilean Patagonia

The southern hake, Merluccius australis, is one of the most important marine fishery resources in Chilean Patagonia. However, little is known about its early life history, especially the transport of eggs and larvae and the connectivity between spawning and nursery areas. An individual-based model (IBM) of the early life stages of M. australis, coupled to a hydrodynamic model, was used to track virtual individuals released from known spawning locations and identify potential nursery areas. The simulations were used to assess connectivity and retention of M. australis eggs and yolk-sac larvae within (and between) the continental shelf (offshore) and the inner sea (inshore) zones. The inshore zone included two spawning and nursery areas (Inner Sea of Chiloé (ISCh), Inner Sea of Moraleda Channel ISM)) and the offshore zone included three spawning and nursery areas (Guafo Island, Guamblin Island, and the Taitao Peninsula). The hydrodynamic model was validated using available observations (oceanographic surveys and the World Ocean Atlas 2018) for winter and spring, periods during which M. australis reproductive activity peaks. The IBM reproduced well the observed seasonal variability of egg and larval distributions. Individuals from the offshore spawning areas had low connectivity with those in the inshore nursery areas in winter and spring. However, individuals from the inshore spawning areas showed a high degree of connectivity with one of the offshore nursery areas (Guafo) during winter and spring, but low connectivity between the inshore ones (ISCh and ISM). Guamblin (in winter) and ISCh (in spring) were the most important retention areas. A conceptual model is proposed to represent the connectivity in early developmental stages between the spawning and nursery areas of M. australis: ichthyoplankton is transported from inshore to offshore in winter when little spawning occurs inshore, but not in spring when spawning and retention increases inshore. Retention in the offshore zone in winter is significant, with almost no connectivity with the inshore zone. Since the main spawning of the species occurs in winter in the offshore zone and secondarily in the inshore zone in spring, the seasonal differences in dispersal patterns seem to be part of the reproductive strategy of the species, which apparently confers advantages for the offspring by promoting development in the most advantageous feeding environment for each season (offshore in winter and inshore in spring).

MPA network design based on graph theory and emergent properties of larval dispersal

Despite the recognised effectiveness of networks of marine protected areas (MPAs) as a biodiversity conservation instrument, MPA network design frequently disregards the importance of connectivity patterns. In the case of sedentary marine populations, connectivity stems not only from the stochastic nature of the physical environment that affects dispersal of early life stages, but also from the spawning stock attributes that affect reproductive output (e.g. passive eggs and larvae) and survivorship. Early life stages are virtually impossible to track in the ocean. Therefore, numerical ocean current simulations coupled with egg and larval Lagrangian transport models remain the most common approach for the assessment of marine larval connectivity. Inferred larval connectivity may differ depending on the type of connectivity considered; consequently, the prioritisation of sites for the conservation of marine populations might also differ. Here, we introduce a framework for evaluating and designing MPA networks based on the identification of connectivity hotspots using graph theoretic analysis. As a case study, we used a network of open-access areas and MPAs off Mallorca Island (Spain), and tested its effectiveness for the protection of the painted comber Serranus scriba. Outputs from network analysis were used to (1) identify critical areas for improving overall larval connectivity, (2) assess the impact of species’ biological parameters in network connectivity and (3) explore alternative MPA configurations to improve average network connectivity. Results demonstrate the potential of graph theory to identify non-trivial egg/larval dispersal patterns and emerging collective properties of the MPA network, which are relevant for increasing protection efficiency.

Nurdle drifters as indicators of egg and early-stage larval fish dispersion and transport on the south-east coast of South Africa

There is considerable uncertainty about fish population connectivity and the trajectory for larval transport following adult spawning migrations from temperate to subtropical oceanic waters off the south and east coast of South Africa. In particular, the role of the Agulhas Current and local wind drift has not been fully elucidated as drivers for connecting coastal and offshore waters, and the results of a previous study that modelled the movements of plastic nurdles following a spill in Durban Harbour are used to infer dispersal and transport. Planktonic fish eggs and early stage larvae are passive and behave in a similar way to nurdles, and the rapid movement of the nurdles provided a unique opportunity to track coastal dispersal trajectories and provide insights into population connectivity in some migratory fish species. Under the variable wind conditions typical along the coast, the nurdles tended to remain localised but when winds blew consistently for a few days in one direction, the nurdles drifted from localised surrogate spawning areas and moved via Agulhas Current connectivity and onshore wind assistance to distal coastal locations hundreds of kilometres away. The rapid and extensive dispersal of nurdles served as a valuable surrogate for understanding dispersal dynamics of planktonic organisms in the surface layer of the ocean which has important implications for genetic dispersal in fishes.

Prevalence, Serotype, Antibiotic Susceptibility, and Genotype of Salmonella in Eggs From Poultry Farms and Marketplaces in Yangling, Shaanxi Province, China.

Poultry products such as eggs provide essential nutrients to the human body and thus play vital roles in the human food network. Salmonella is one of the most notorious foodborne pathogens and has been found to be prevalent in eggs. To better understand the characteristics of Salmonella in eggs, we investigated the prevalence of Salmonella spp. in 814 fresh eggs collected from poultry farms and retail marketplaces in Yangling, Shaanxi Province, China. The serotype, genotype, and antibiotic susceptibilities of 61 Salmonella isolates recovered from the eggs were analyzed. The average detection rate of Salmonella-positive eggs was 5.6%, with 6.6% of the eggs collected from poultry farms and 5.1% from marketplaces. Thirteen serotypes were identified from the 61 isolates, among which Salmonella Typhimurium (24.5%) and Salmonella Indiana (22.9%) were the most prevalent serotypes. Other dominant serotypes included Salmonella Thompson (13.1%) and Salmonella Enteritidis (11.4%), with the remaining nine serotypes detected at low rates (1.6–4.9%). All the Salmonella isolates tested were resistant to sulfisoxazole (100.0%). The majority (77.1%) of the isolates were resistant to nalidixic acid, amoxicillin-clavulanate, and ampicillin, while nearly two-thirds (63.9–68.9%) were resistant to trimethoprim–sulfamethoxazole, kanamycin, tetracyclines, and chloramphenicol. The rate of resistance to ciprofloxacin was 40.1%; the resistance rates to streptomycin, ceftiofur, and ceftriaxone ranged from 21.3 to 26.2%; and those to gentamicin, amikacin, and cefoxitin were relatively low (3.3–16.4%). Forty-nine (80.3%) Salmonella isolates exhibited resistance to multiple antibiotics, 20 (32.8%) of which were resistant to at least 10 antibiotics. Subtyping by pulse-field gel electrophoresis revealed a close genetic relatedness of Salmonella isolates from poultry farms, in striking contrast to the high diversity of the isolates obtained from marketplaces. Isolates of the same serotype always shared identical genotype and antibiotic resistance profiles, even the ones that were recovered from eggs sampled at different locations and times. These findings indicate that diverse Salmonella spp. with high rates of multidrug resistance are prevalent in fresh eggs in the study area. More attention should be paid to egg production, transportation, and storage to prevent foodborne outbreaks caused by Salmonella.

Analysis of the rates of development and growth of Brachymystax lenok Savinovi during artificial reproduction by the industrial method

The article presents the results of the first research on artificial reproduction in industrial conditions of the endemic, narrow-areal subspecies of Brachymystax lenok Savinovi, which lives in lake Markakol, East Kazakhstan region. The indicators of the heat sum characteristic for each stage of development, the rate of development and growth of the Markakolsky lenok from the moment of pre-breeding to late juveniles are described. To develop technological approaches for artificial fish reproduction, one of the most important points is to determine the optimal conditions for each stage and assess the risks (loss of fish products). At the stage of insemination and transportation of eggs to the place of incubation, the loss was 50 %. The largest losses of fish products were registered during the incubation stage. The most painlessly passed the period of holding and lifting on the float, where the loss was only 3 %. When growing pre-larvae and larvae in the pool, the daily waste did not exceed 1 %. Small-sized animals that were unable to adapt to artificial feeds fell into the waste. Losses during this period amounted to 15 % of the previous stage. In General, the yield of juveniles from the moment of fertilization to the end of the experiment was 16 %. The crucial factor in the development and growth of Lenok Markakolosky is the temperature regime. For the period of embryonic development, the most favorable water temperature is 7–8 °C. From the moment of hatching, the water temperature must be increased to 10–12 °C, and the optimal temperature for the cage growing of fingerlings varies from 12 to 14 °C.

Characterization of ethanol-induced egg white gel and transportation of active nutraceuticals

This paper investigated the gelling characteristics of ethanol-induced egg white gel (EEWG) and also evaluated the ability of EEWG to delivery curcumin and tea polyphenols (TP). Results showed that a high concentration of ethanol induced egg white (EW) to form gel, which was attributed to the increase of zeta potential in absolute value and free sulfhydryl content. A high concentration of ethanol reduced the intrinsic fluorescence, mainly of tryptophan, and increased the viscosity. EEWG with a high concentration of protein represented greater hardness and water-holding capacity combined with the formation of abundant small bubbles. The addition of TP decreased the hardness value and water-holding capacity and reduced the storage modulus and loss modulus, determined by a rheometer, for further prevention of EW protein denaturation. The curcumin and TP stabilities were improved after adding a higher concentration of protein during storage. Adding a proper concentration of ethanol (30–40 mL/100 mL) increased the bioaccessibility of curcumin and improved the antioxidant activity and protein digestibility, but this was decreased after EEWG was loaded with TP. These results suggested that EW protein could improve the delivery of a hydrophobic active substance.

DNA barcoding of fish eggs collected off northwestern Cuba and across the Florida Straits demonstrates egg transport by mesoscale eddies

AbstractIdentifying spawning sites for broadcast spawning fish species is a key element of delineating critical habitat for managing and regulating marine fisheries. Genetic barcoding has enabled accurate taxonomic identification of individual fish eggs, overcoming limitations of morphological classification techniques. In this study, planktonic fish eggs were collected at 23 stations along the northwestern coast of Cuba and across the Florida Straits to United States waters. A total of 564 fish eggs were successfully identified to 89 taxa within 30 families, with the majority of taxa resolved to species. We provide new spawning information for Luvarus imperialis (Louvar), Bothus lunatus (Plate Fish), Eumegistus illustris (Brilliant Pomfret), and many economically important species. Data from most sites supported previously established patterns of eggs from neritic fish species being found on continental shelves and oceanic species spawning over deeper waters. However, some sites deviated from this pattern, with eggs from reef‐associated fish species detected in the deep waters of the Florida Straits and pelagic species detected in the shallow, continental shelf waters off the coast of northwestern Cuba. Further investigation using satellite imagery revealed the presence of a mesoscale cyclonic eddy that likely entrained neritic fish eggs and transported them into the Florida Straits. The technique of combining DNA‐based fish egg identification with remotely‐sensed hydrodynamics provides an important new tool for assessing the interplay of regional oceanography with fish spawning strategies.

SUN-736 Knockout of Membrane Androgen Receptor ZIP9 Results in Reduced Female Fecundity and Abnormal Egg Activation in Zebrafish

Recently, our research group cloned and characterized a putative membrane androgen receptor from teleost ovarian tissue that was found to be homologous with the zinc transporter protein ZIP9 (Slc39a9). To date, ZIP9 is the only zinc transporter that is known to be ligand activated or possess steroid receptor activity. Since the discovery of its androgen receptor activity, ZIP9 has been found to mediate androgen actions in a variety of tissues including teleost ovarian follicle cells, human cancer cell lines, and murine Sertoli cells. However, ZIP9 has not been examined in an in vivo model so the precise physiological functions of this receptor remain unclear. A ZIP9-mutant strain of zebrafish was developed using a CRISPR-Cas9 system in order to examine the role of the protein in teleost reproduction. While ZIP9-mutant males had similar breeding occurrence and fertilization rates to wild-type fish, mutant females exhibited severe reductions in fecundity compared to wild-type fish. ZIP9-mutant females spawn significantly fewer eggs of which a high proportion failed to undergo chorion elevation, a characteristic of normal egg activation. Eggs that showed this failed chorion elevation phenotype had significantly lower fertilization rates and produced larvae that exhibit a high incidence of pericardial/yolk sac edema and reduced growth compared to larvae hatched from wild-type eggs. However, no differences were observed in the proportions of oocytes at later stages of development between ZIP9-mutant and wild-type fish, suggesting the observed phenotypes are not related to abnormal oogenesis. We observed that mature wild-type eggs have numerous cortically located vesicles that are autofluorescent under ultraviolet light and decrease in number when the eggs undergo activation, suggesting they undergo exocytosis during the cortical reaction. While zinc is known to be stored in vesicles that undergo exocytosis in mammalian eggs, the role of zinc in teleost egg activation is currently unknown. In eggs from wild-type fish, we observed an increase in extracellular zinc levels upon egg activation and treatment with a zinc ionophore (zinc pyrithione) significantly reduced the number of eggs that undergo normal chorion elevation when activated. This suggests a role for zinc in zebrafish egg activation similar to that observed in mammals. Of interest, ZIP9-mutant eggs that did not undergo chorion elevation had significantly smaller vesicles than those found in wild-type fish eggs. This abnormal vesicle morphology and failure to undergo chorion elevation suggest a role of ZIP9 in egg activation. Additional insight into the role of zinc in zebrafish egg activation and the mechanism by which ZIP9 disruption leads to abnormal cortical vesicles and egg activation will help determine if ZIP9 plays a role in zinc transport and flux in zebrafish eggs during activation.