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The ability of fish to sustain environmental perturbations during fragile early‐life stages can be of vital importance for populations and species facing rapid global environmental change. One of the potential challenges for aquatic organisms, including teleost fish, is rising concentration of dissolved organic carbon (DOC) in freshwater environments, known as brownification, which causes a cascade of changes including a decreased visibility and pH. Conversely, humic substances are increasingly recognised for their potential antimicrobial and immunostimulant properties. The questions remain whether exposure to humic waters high in DOC during the development causes significant perturbation, and to what extent genetic and parental factors may maintain optimal development in such a possibly challenging environment.To address these questions, we generated pure and hybrid (inter‐population) crosses of Eurasian perch (Perca fluviatilis) originating from clear‐water and humic lakes. Fertilised eggs from each cross were exposed to natural humic and clear‐water lake water. Intra‐chorionic space diameter (embryo diameter) and hatching success were recorded.Perch embryos successfully developed even in a small volume of water (5 mL) and majority hatched (70%) by 13 day post‐fertilisation. Embryo diameter was influenced by the interaction between cross type and treatment where embryos with maternal clear‐water origin were smaller than embryos of humic water origin in both clear‐water and humic water treatments. The probability of hatching was not related to female size, but rather to embryo diameter at the eyed stage and the interaction between cross type and treatment, resulting in pure clear‐water crosses hatching earlier and at higher numbers.Our study shows that effects of humic water are not uniformally negative in perch and discloses population‐dependent responses to humic water exposure during development. Our experimental design also illustrates the utility of multi‐well plates for conducting complex high‐throughput experiments beyond traditional model species and opens new possibilities for testing perch genotype–environment associations in early‐life traits.Taken together, results of this study add to the growing evidence that humic substances may have complex effects on fish during early life, motivating further investigations on their role in shaping natural phenotypes and potential use in the applied sector. [ABSTRACT FROM AUTHOR]

High larval and frymortality has been amajor challenge to the commercial culture of the African bony-tongue (Heterotis niloticus). Research indicates inadequate feeding to be a possible cause of the high mortality rates of larvae/fry grown in captivity. An experiment was conducted to first describe the developmental stages of H. niloticus eggs and larvae until schooling, 6 days after hatching (DAH), at 26°C. The morphological development, survival, growth (weight gain and length), and swimming behavior of the larvae were monitored. A follow-up feeding trial was conducted with H. niloticus fry from 6 to 27 DAH involving four treatments: feeding with Artemia nauplii; a combined feed of 50% Artemia nauplii and 50% rotifers (w/w); feeding with rotifers; and no feeding. The activities of three digestive enzymes (trypsin, lipase, and amylase)were assessed in fry exposed to the live feed treatments. At hatching, the larvae had a large, vascularized yolk sac filled with yolk platelets, which occupied approximately one-third of the total body length of the abdominal cavity. Yolk platelet reabsorption started at 1 DAH and was complete at 6 DAH. Metamorphosis was completed at 6 DAH, and schooling behavior was observed. For the feeding trial, the fry that received Artemia nauplii underwent the fastest development until 27 DAH. Similarly, the survival rate was considerably higher in fry fed with Artemia nauplii than in those that received a combination of Artemia nauplii and rotifers or only rotifers. Overall, the survival rates for fry fed with Artemia nauplii and larvae co-fed were 72.7% ± 0.9% and 41.2% ± 3.3%, respectively. Fry did not survive until 27 DAH in the rotifer-fed and unfed treatment groups. Digestive enzyme activity differed significantly (p< 0.05) between treatments and sampling dates. All digestive enzymes were detectable at the onset of mouth opening (5 DAH) and fluctuated through the 7 and 9 DAH. Lower enzyme activity was observed when the fry were subjected to starvation or the rotifer treatment. Results indicate that Artemia nauplii is the best live feed organism for H. niloticus larviculture. [ABSTRACT FROM AUTHOR]

The egg tooth of squamates is a true tooth that allows them to break, tear, or cut the eggshell during hatching. In this clade there are some uncertainties concerning the egg tooth implantation geometry, the number of germs, and their fates during embryonic development. Here, we used X-ray microtomography and light microscopy, focusing on the egg tooth and remaining premaxillary teeth of the sand lizard (Lacerta agilis , Squamata: Unidentata). The developing egg tooth of this species passes through all the classic stages of tooth development. We did not find any evidence that the large size of the egg tooth is related to the merging of two egg tooth germs, which has recently been suggested to occur in snakes. Instead, this feature can be attributed to the delayed formation of the neighbouring regular premaxillary teeth. This might provide more resources to the developing egg tooth. At the last developmental stage, the egg tooth is a large, midline structure, bent forward as in most oviparous Unidentata. It is characterized by pleurodont implantation, and its base is attached to the pleura and a peculiar ridge of the alveolar bone. The attachment tissue contains periodontal ligament-like tissue, acellular cementum-like tissue, and alveolar bone. [ABSTRACT FROM AUTHOR]

Background: Plant-parasitic nematodes are economically important pests responsible for substantial losses in agriculture. Researchers focusing on plant-parasitic nematodes, especially on finding new ways of their control, often need to assess basic parameters such as their motility, viability, and reproduction. Traditionally, these assays involve visually counting juveniles and eggs under a dissecting microscope, making this investigation time-consuming and laborious. Results: In this study, we established a procedure to efficiently determine the motility of two plant-parasitic nematode species, Heterodera schachtii and Ditylenchus destructor, using the WMicrotracker ONE platform. Additionally, we demonstrated that hatching of the cyst nematode H. schachtii can be evaluated using both the WMicrotracker ONE and by assessing the enzymatic activity of chitinase produced during hatching. Conclusions: We present fast and straightforward protocols for studying nematode motility and hatching that allow us to draw conclusions about viability and survival. Thus, these methods are useful tools for facilitating fast and efficient evaluation in various fields of research focused on plant-parasitic nematodes. [ABSTRACT FROM AUTHOR]

Cu–Cr–Zr alloy's low wear resistance due to defect generation and cavity creation during the laser powder bed fusion (LPBF) process prevents its use in the aerospace and automotive industries. Hence, this research focuses on enhancing the wear resistance by mitigating defect formations during the LPBF process. The key LPBF process parameters such as exposure span (ES) of 350, 550, and 650 µs; laser power (LP) of 280, 360, and 440 W; and hatching range (HR) of 0.04, 0.07, and 0.1 mm were chosen and examined to reduce the cavity formations and to increase the indentation effect and thereby enhancing the wear resistance of the printed Cu alloy components. Criteria Importance Through Intercriteria Correlation (CRITIC) associated with COmplex PRoportional ASsessment (COPRAS)–based multi-criterion decision-making (MCDM) technique was employed to substantiate the results obtained from the experimental analysis. Comparative analysis was performed for four different combinations of parameters to examine the impact of individual parameters in influencing the wear resistance. The research outcome confirms that the reduced cavity percentage of 0.08% with the minimal wear rate of 0.83 × 10−5 mm3/Nm and maximum nanohardness of 2.82 GPa was attained during the implementation of minimum ES of 350 µs and HR of 0.04 mm with maximum LP of 440 W. Furthermore, during the examination of wear mechanism, the transformation of adhesion to abrasion wear mode was evident which was induced by the defect formations. However, the mitigation of defect formations was also addressed in this investigation. [ABSTRACT FROM AUTHOR]

This study investigated the seasonal changes in embryonic development of the red snow crabs inhabiting the deep sea using wild and captive ovigerous females. The embryonic stages were categorised into 14 groups based on their external morphology. Females with recently spawned eggs (between stage 1 and early stage 3), those with the eggs at the midterm stage (mainly stages 7 and 8), and those with eggs just before hatching (stage 14) were observed simultaneously from January to March indicating a 2-year reproductive cycle. These findings aid in understanding and identifying the spawning years of the red snow crabs sampled from their natural habitats. [ABSTRACT FROM AUTHOR]

Exploring the effects of water temperature on egg development in skipjack tuna (Katsuwonus pelamis) has substantial implications for evaluations of wild spawning habitats. In the present study, we examined the hatching success and duration as a function of temperature from 21 to 33°C under captive environments. A high hatching rate of over 50% between 23 and 31°C was observed, with the shortest hatching duration at 31°C. Because the egg period is vulnerable to predators, a shortened hatching duration with warming water would be ecologically advantageous for K. pelamis, as its main spawning grounds are located in tropical areas. [ABSTRACT FROM AUTHOR]

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Mud crabs are common edible crustaceans, which are fished along the coasts of India. Scylla tranquebarica (Fabricius 1798), commonly called green crab is one of the most economically important portunid crab in India. The study was carried out to determine the sex ratio, maturation and spawning, gonadosomatic index, fecundity and egg diameter. Sex ratio of 1 female to 1.3 male gave good results. Size at first maturity was observed at 11 cm carapace width (CW) in males and 10 cm (CW) in females. The highest GSI values in males (6.17) and females (5.12) were observed in the month of October. The maximum number of eggs produced by the females was up to 5 million. The egg diameter was recorded in the range of 0.69 to 0.76 mm. The incubation period was 11-13 days. The hatching success average percentage was recorded as 80%. For the incubation and larval rearing of mud crab, Scylla tranquibarica, the optimum requirement of water temperature and salinity were recorded as 28°C and 30 ppt, respectively. [ABSTRACT FROM AUTHOR]

Abstract Background Plant-parasitic nematodes are economically important pests responsible for substantial losses in agriculture. Researchers focusing on plant-parasitic nematodes, especially on finding new ways of their control, often need to assess basic parameters such as their motility, viability, and reproduction. Traditionally, these assays involve visually counting juveniles and eggs under a dissecting microscope, making this investigation time-consuming and laborious. Results In this study, we established a procedure to efficiently determine the motility of two plant-parasitic nematode species, Heterodera schachtii and Ditylenchus destructor, using the WMicrotracker ONE platform. Additionally, we demonstrated that hatching of the cyst nematode H. schachtii can be evaluated using both the WMicrotracker ONE and by assessing the enzymatic activity of chitinase produced during hatching. Conclusions We present fast and straightforward protocols for studying nematode motility and hatching that allow us to draw conclusions about viability and survival. Thus, these methods are useful tools for facilitating fast and efficient evaluation in various fields of research focused on plant-parasitic nematodes.

Abstract Narrow clawed crayfish, Pontastacus (Astacus) leptodactylus, represents an ecologically and economically valuable freshwater species. Despite the high importance of artificial breeding for conservation purpose and aquaculture potential, hatching protocols have not been developed so far in this species. Further, limited knowledge exists regarding the artificial egg incubation, the temperature effect on embryonic development, hatching synchronization and hatching rate. In the present study we investigated the temperature increase (from 17 oC to 22oC) effects in two different embryonic developmental stages of P. leptodactylus. Furthermore, two primer pairs for the Fibroblast Growth Factor Receptor 4 (FGFR4) gene cDNA amplification were successfully designed, characterising for the first time the FGFR4 gene in P. leptodactylus in relation to different developmental stages and temperatures. Apart from the FGFR4 gene, the Na+/K+-ATPase α-subunit expression was also explored. Both the FGFR4 and Na+/K+-ATPase α-subunit expression levels were higher in embryos closer to hatching. Egg incubation at 22oC for seven days led to significant increase of FGFR4 expression in embryos from earlier developmental stages. Nevertheless, temperature increase did not affect FGFR4 expression in eggs from latter developmental stages and Na+/K+-ATPase α-subunit expression in all developmental stages. Temperature increase represents therefore probably a promising strategy for accelerating hatching in freshwater crayfish particularly in early developmental stages. Specifically, our results indicate that FGFR4 expression increased in embryonic stages closer to hatching and that temperature influences significantly its expression in embryos from earlier developmental stages. Overall, these findings can provide a better understanding of artificial egg incubation of P. leptodactylus, and therefore can be employed for the effective management of this species, both for economic and biodiversity retention reasons.

Senegalese sole, Solea senegalensis, is a flatfish of high commercial value in the world. It has been identified as an interesting and promising species for marine commercial aquaculture diversification in Europe for at least four decades and was introduced to China in 2003. Early ontogenesis from embryo to juvenile stages in S. senegalensis was analysed under controlled laboratory conditions to provide morphological information for aquaculture. From 0 to 59 days post hatching (dph), 10–20 larvae were sampled and measured each day (0–17 dph) or every 2–6 days (17–59 dph). Morphological characteristics from the egg to the juvenile stage were described. The eggs were separate and spherical with multiple oil globules. After 3 dph, the yolk sac was completely absorbed, mouth and anus were open, a swim bladder appeared, and larvae began feeding on rotifers (Brachionus plicatilis). The larvae began metamorphosis as the notochord flexed upward and the left eye migrated upward after 10 dph. The left eye migrated to the dorsal midline at 15 dph. At 19 dph, the left eye was translocated to the right‐ocular side, and the juveniles adopted a benthic lifestyle. The swim bladder degenerated, and the juveniles completed metamorphosis at 23 dph. The growth patterns of some parameters (TL, SL, BH, BW) during larval and juvenile development stages were identified. The inflection points, which are slopes of growth changes, were calculated in growth curves. Three inflection points occurring in the growth curves of larvae and juveniles were found to be associated with metamorphosis, weaning, and transitions in feeding habits. The basic information of embryo development and ontogenesis in this study represents a valuable contribution to the S. senegalensis industry, especially in artificial breeding and rearing techniques. [ABSTRACT FROM AUTHOR]

Laboratory studies on embryos of salmonids, such as the brown trout (Salmo trutta), have been extensively used to study environmental stress and how responses vary within and between natural populations. These studies are based on the implicit assumption that early life‐history traits are relevant for stress tolerance in the wild. Here we test this assumption by combining two data sets from studies on the same 60 families. These families had been experimentally produced from wild breeders to determine, in separate samples, (1) stress tolerances of singly kept embryos in the laboratory and (2) growth of juveniles during 6 months in the wild. We found that growth in the wild was well predicted by the larval size of their full sibs in the laboratory, especially if these siblings had been experimentally exposed to a pathogen. Exposure to the pathogen had not caused elevated mortality among the embryos but induced early hatching. The strength of this stress‐induced change of life history was a significant predictor of juvenile growth in the wild: the stronger the response in the laboratory, the slower the growth in the wild. We conclude that embryo performance in controlled environments can be a useful predictor of juvenile performance in the wild. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Kirkuk University for Agricultural Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Selenium is an essential mineral for poultry. The conflicting reports about its in ovo injection are the justification for the more detailed investigation. Objectives: The aim of this study was to investigate the effects of in ovo injection of organic selenium on the hatching traits of broiler chickens and their performance. Methods: Three hundred and twenty eggs of Ross 308 strain with an average weight of 65 g and 160 chicks were randomly divided into 4 treatment groups (each with 8 replicates of 10 eggs each for hatching parameters and 4 replicates of 10 chicks for broiler farming parameters): negative control (no injection), positive control (in ovo injection of 0.272 mL of normal saline solution) and 2 selenium treatments (in ovo injection of 2.72 or 5.44 μg of organic selenium). Injection was into the amniotic sac on the 10th day of incubation. Effects of in ovo injection on hatching and performance traits, blood parameters, immune responses, carcass characteristics, meat fatty acid profile, cecal microbial population and selenium consternation in the tibia were measured. Results: Fewer chicks from the injected treatments hatched than from the negative control group (p < 0.01). However, the injection of selenium increased feed intake and the final weight of the birds (p < 0.01). Blood parameters were also affected. Glucose and cholesterol in experimental treatment chicks was lower than those of the controls (p < 0.01), whereas blood lipoproteins (VLDL, LDL and HDL) and the ratio of cholesterol to HDL was significantly increased in the treatments injected with selenium (p < 0.01). There was no significant difference in the immune response or microbial population between the experimental groups, but carcass components, such as thigh, breast, wing and abdominal fat weight, were significantly greater in the selenium treatments. Conclusions: Intra‐egg injection of organic selenium produced favourable effects on performance of broiler chickens, although it had no effect on immune response or microbial population. However, the negative effect on hatching of chickens needs to be prevented to result in an acceptable economic return for the producer. [ABSTRACT FROM AUTHOR]

Hatching corresponds to the moment an individual leaves its egg envelope. Yet, hatching has scarcely aroused the interest of biologists, and the question posed here, 'why do larvae hatch when they do?' appears to have been rarely asked. In this proof-of-concept study, we tested the hypothesis that fish larvae hatch when a specific ratio between egg surface area (ESA) and larval surface area (LSA) is reached, irrespective of egg diameter and abiotic factors. An estimated mean ratio of 1: 1.52 (CI = 1.39–1.63) was obtained from the eggs of 33 species of teleosts, with diameters ranging from 0.63 to 5.7 mm. We assume that this ratio has a value beyond which the oxygen supply through the egg surface cannot cope with the oxygen requirements of the embryo. The detailed ecological consequences are unknown but can be expected to impact fisheries and aquaculture negatively. [ABSTRACT FROM AUTHOR]

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Narrow clawed crayfish, Pontastacus (Astacus) leptodactylus, represents an ecologically and economically valuable freshwater species. Despite the high importance of artificial breeding for conservation purpose and aquaculture potential, hatching protocols have not been developed so far in this species. Further, limited knowledge exists regarding the artificial egg incubation, the temperature effect on embryonic development, hatching synchronization and hatching rate. In the present study we investigated the temperature increase (from 17 oC to 22oC) effects in two different embryonic developmental stages of P. leptodactylus. Furthermore, two primer pairs for the Fibroblast Growth Factor Receptor 4 (FGFR4) gene cDNA amplification were successfully designed, characterising for the first time the FGFR4 gene in P. leptodactylus in relation to different developmental stages and temperatures. Apart from the FGFR4 gene, the Na+/K+-ATPase α-subunit expression was also explored. Both the FGFR4 and Na+/K+-ATPase α-subunit expression levels were higher in embryos closer to hatching. Egg incubation at 22oC for seven days led to significant increase of FGFR4 expression in embryos from earlier developmental stages. Nevertheless, temperature increase did not affect FGFR4 expression in eggs from latter developmental stages and Na+/K+-ATPase α-subunit expression in all developmental stages. Temperature increase represents therefore probably a promising strategy for accelerating hatching in freshwater crayfish particularly in early developmental stages. Specifically, our results indicate that FGFR4 expression increased in embryonic stages closer to hatching and that temperature influences significantly its expression in embryos from earlier developmental stages. Overall, these findings can provide a better understanding of artificial egg incubation of P. leptodactylus, and therefore can be employed for the effective management of this species, both for economic and biodiversity retention reasons. [ABSTRACT FROM AUTHOR]

Iodine is proven to be an effective disinfectant for fish eggs and is commonly used in a hatchery to improve hatching and survival rates. However, tolerance to iodine can vary in different fish species, and it is essential to determine the optimal concentration to ensure successful hatchery production. This study investigated the optimum concentration and exposure time to iodine during incubation to improve rabbitfish larvae's hatching and fertilization rate from 4/2022 -- 8/2022 in Thua Thien Hue, Vietnam. The study consisted of two experiments: Experiment 1 focused on different iodine concentrations: 0 ppm (C1), 50 ppm (C2), 100 ppm (C3), and 150 ppm (C4). Experiment 2 explored three exposure times: 10 minutes (T1), 20 minutes (T2), and 30 minutes (T3) to increase the fertilization, hatching, and survival rates at five days post-hatching. Data were compiled, analyzed, and compared by ANOVA using SPSS ver. 22.0. The results showed that 100 ppm iodine concentration at 20 minutes of exposure resulted in the optimum hatching, fertilization, and survival rates of S. guttatus during artificial reproduction. In the future, integrated solutions in the use of iodine solution for egg treatment and natural food supplementation at the larval stage should be recommended to improve the efficiency in artificial hatchery production of Rabbitfish. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of chlorpyrifos on the embryonic development of Clarias gariepinus. Freshly fertilized eggs of C. gariepinus were subjected to varying concentrations of chlorpyrifos (0.01, 0.1, 1.0, and 10 μg L-1) during embryogenesis in a static renewal bioassay. The investigation focused on three crucial stages of embryogenesis: gastrulation, segmentation, and hatching. During the gastrulation stage, observations of germ rings, caudal edge, and cephalic edge were consistent across both treatment and control groups. Results from the segmentation stage revealed complete somite blocks in both treatment and control groups. At hatching, the optic primordial, myotomal muscle, yolk sac, notochord, and mouth gape were fully formed at 24 hours posthatching in the control and treatment groups, except at the highest concentration (10 μg L-1), where hatching did not occur. Notably, there were no significant aberrations during the embryogenesis period across the treatments. The hatchability test indicated that at the lowest concentration of chlorpyrifos (0.01 μg L-1), 60% of the thirty fertilized eggs hatched. The 0.1 μg L-1 treatment exhibited a hatching rate of 40%, while the 1.0 μg L-1 treatment group showed a hatching rate of 20%. Although exposure of catfish embryos to chlorpyrifos at reduced concentrations did not result in significant effects, except at 10 μg L-1, the mere presence of chlorpyrifos in water bodies underscores the need for further evaluation of the subtle effects at environmentally relevant concentrations, which can only be identified through mechanistic analysis, on the development of fish eggs, larvae, and other aquatic fauna. [ABSTRACT FROM AUTHOR]

Studies comparing mating ratio after forced molting are important for improving the efficiency of broiler breeder flocks. This study examined the effect of mating ratios on Egg production, chick weight, fertility, hatchability and embryonic mortality rate in Arbor Acres Plus broiler breeders post-moult phase. A total of 195 birds (62 weeks old), consisting of 15 cocks and 180 hens were randomly allocated with uniform body weight in a Completely Randomized Design into three groups based on the mating ratio (cock to hen). The groups included ratios of 1:10, 1:12, and 1:14, with each group replicated 5 times. Eggs were collected twice a day, and stored for 7 days at room temperature before placing them in the incubator. Results showed that mating ratios 1:10 and 1:12 had a positive effect on fertility rate and total hatchability compared to the 1:14 ratio. However, mating ratios did not affect laying rate, egg weight, egg mass, chick weight, hatchability of fertile eggs, and embryonic mortality rate. In conclusion, to reduce the cost of raising and caring cocks, a mating ratio of one cock to every twelve hens can be used for broiler breeders after forced molting to obtain the best fertility and hatching results.

ABSTRACT Managing fertile eggs and minimizing seasonal impacts is crucial in poultry farming. This study evaluated the effects of the storage time of fertile eggs, broiler breeder strain, and age on hatchability and first-week broiler performance. Twelve treatments were carried out in a factorial arrangement with two broiler breeder strains (Cobb MV and Ross 308AP), two breeder age intervals (between 30-40 weeks and between 50-60 weeks), and three egg storage times (4, 7 and 9 days). The Ross 308AP strain showed the highest hatchability (91.74%) at 30-40 weeks, while Cobb MV had the greatest weight gain (162.75g) from days 1 to 7 at 50-60 weeks. Longer egg storage affected weight gain at 7 days for Cobb MV. Nine-day storage reduced chick weight (45.46g) from breeders aged 50-60 weeks. Lower first-stage embryonic mortality was observed in Ross 308 AP (3.83%) in breeders aged 30-40 weeks (4.13%), and in eggs stored for 4 days (4.01%). The Ross 308AP had the greatest percentage of infertile eggs (10.25%), and breeders aged 50-60 weeks showed greater percentages of infertility (10.14%). The Cobb MV had lower second-stage embryonic mortality but higher percentages of discarded chicks. Hatchability and first-week broiler performance depend on storage time, breeder age and strain.

Abstract Transfer RNA-derived small RNAs (tsRNAs) have been shown to be involved in early embryo development and repression of endogenous retroelements in embryos and stem cells. However, it is unknown whether tsRNAs also regulate embryo hatching. In this study, we mined the sequencing data of a previous experiment in which we demonstrated that the microRNA (miRNA) cargo of preimplantation embryonic extracellular vesicles (EVs) influences embryo development. We thus profiled the tsRNA cargo of EVs secreted by blastocysts and non-blastocysts. The majority of tsRNAs was identified as tRNA halves originating from the 5´ ends of tRNAs. Among the 148 differentially expressed tsRNAs, the 19 nt tRNA fragment (tRF) tDR-14:32-Glu-CTC-1 was found to be significantly up-regulated in EVs derived from non-blastocysts. RT-qPCR assays confirmed its significant up-regulation in non-blastocyst embryos and their conditioned medium compared to the blastocyst group (P

Transfer RNA-derived small RNAs (tsRNAs) have been shown to be involved in early embryo development and repression of endogenous retroelements in embryos and stem cells. However, it is unknown whether tsRNAs also regulate embryo hatching. In this study, we mined the sequencing data of a previous experiment in which we demonstrated that the microRNA (miRNA) cargo of preimplantation embryonic extracellular vesicles (EVs) influences embryo development. We thus profiled the tsRNA cargo of EVs secreted by blastocysts and non-blastocysts. The majority of tsRNAs was identified as tRNA halves originating from the 5´ ends of tRNAs. Among the 148 differentially expressed tsRNAs, the 19 nt tRNA fragment (tRF) tDR-14:32-Glu-CTC-1 was found to be significantly up-regulated in EVs derived from non-blastocysts. RT-qPCR assays confirmed its significant up-regulation in non-blastocyst embryos and their conditioned medium compared to the blastocyst group (P < 0.05). Inhibition of tDR-14:32-Glu-CTC-1 by supplementing antagomirs to the conditioned medium improved embryo hatching (P < 0.05). Transcriptomic analysis of embryos treated with tDR-14:32-Glu-CTC-1 antagomirs further showed differential expression of genes that are associated with embryo hatching and implantation. In summary, tDR-14:32-Glu-CTC-1 is up-regulated in non-blastocyst embryos and their secretions, and inhibition of tDR-14:32-Glu-CTC-1 promotes embryo hatching, while influencing embryo implantation-related genes and pathways. These results indicate that embryonic EVs containing specific tRFs may regulate preimplantation embryo development. [ABSTRACT FROM AUTHOR]

Background: In ovo application is the process of administering some nutrients or components into the egg. The main purpose of this application is to ensure that some nutrients are provided to chicks with a short incubation period. Few studies were conducted with taurine in fertile eggs; especially, no observation of hatchability and chick quality has been found. In addition, taurine has an anti‐stress impact that fights oxidative factors. Objective: To assess the hatchability and chick quality after in ovo taurine administration. To determine the stress that may occur as a result of in ovo application and whether taurine has a stress‐reducing effect. Methods: A total of 1200 fertile eggs from a 34‐week‐old broiler breeder (Ross 308) flock were categorized into 4 groups with 75 eggs per replicate: control (uninjected), taurine group (0.30 mL dissolved taurine in distilled water), sham control (sterile distilled water) and perforation (eggs perforated and then waxed). On day 14 of incubation, an in ovo injection was administered to the albumen. Data on hatching parameters and hepatic HSP70 levels were obtained using relevant formulas and western blotting, respectively. Results: Control chicks exhibited higher hatchability than other groups, with the taurine group showing the lowest hatchability. The HSP70 levels were the highest in the perforation group compared to the control group. An increase of 21.37% in the taurine group and 83.45% in the sham control group was observed compared to the control group. Conclusions: The findings suggest that in ovo application may induce increased stress, whereas taurine may have positive effects in mitigating the stress caused by in ovo application. [ABSTRACT FROM AUTHOR]

Introduction: Nowadays, using unconventional water, especially in arid and semi-arid areas, has increased as a result of global population increase, urbanization and climate change. Using these water sources for aquaculture is suggested for optimal utilization and reduction of their adverse effects on the environment. Artemia is an aquatic crustacean that is distributed all over the world. It plays an important role in the aquatic food chain due to containing a variety of high nutrients such as proteins, amino acids, fatty acids, vitamins and antioxidants. These organisms are the most common live-food item in the aquaculture industry to feed the larval stages of fish and crustaceans in different parts of the world. Artemia can grow in various saltwater environments. The water sources suitable for them do vary considerably in terms of ionic composition, climatic conditions, seasonality, productivity, altitude, and other characteristics. Among the species of the genus Artemia, A. franciscana is the most important one for aquaculture use, and it has been introduced in salt-waters for integrated Artemia-salt production. This species is characterized by the standard features of the short-life cycles: highly adaptable to adverse environmental conditions, easy cultivation and easy availability. The aim of this study was to investigate the feasibility of hatching and growth performances of Artemia (A. franciscana) in the unconventional water conditions in Sistan region, Southeast Iran under laboratory conditions. Materials and methods: The present study was carried out in the Laboratory of Reproduction and Breeding Aquatic Animals, Hamoun International Wetland Research Institute located in Zabol Research Institute in February 2024. Hatching rate, growth performance (comparison of body length and width), abundance of each biological form and health (comparison of morphological characteristics) of A. franciscana under breeding conditions of unconventional waters in Sistan region were investigated in this study. For this purpose, Artemia cysts were hatched in plastic jars using three replicated treatments, i.e., control (T1; distilled water + sea salt; 35.37 ppt), desalination wastewater (T2; 48.88 ppt), deep aquifer well water (T3; 16.35 ppt), and well water (T4; 28.46 ppt). All treatments were kept under standard conditions including temperature 27 °C, light 37 μmol/m2 /s as well as 12 hours light and 12 hours darkness (12L:12D) during the experimental period. After 48 h of incubation, the hatching rate of Artemia cysts was analyzed. In order to evaluate growth performance and health status, at least 30 specimens from each treatment were randomly selected and photographed, then body length and width were measured using Digimizer software. Water quality parameters including temperature, pH, salinity, ammonia, nitrate, nitrite, sulfate, hardness, Cl, Mg and Cu were recorded using standard methods during the experiment. All data obtained in this study were analyzed using One-Way ANOVA, followed by Tukey's test for any significant differences among the treatments. Pearson’s correlation coefficient (r) was calculated for the statistical interpretation of the influence of the physicochemical variables on hatching rate and body length. Results and discussion: The results showed that hatchability of cysts and body length of Artemia were significantly different among treatments (p<0.05). The highest value of 71.32 ± 5.41% was recorded in T1 followed by 67.19 ± 4.28% in T3, 51.19 ± 2.33% in T4 and 47.81 ± 2.78% in T2 on the 48 h after cyst incubation. The length (mm) of Artemia was higher (0.64 ± 0.06) in T3 than in T1 (0.62 ± 0.05), T4 (0.59 ± 0.04) and T2 (0.56 ± 0.05). Instar 2 was the dominant form in T3 and T4, while instar 2 was the dominant form in the other two treatments. The morphological characteristics of Artemia were similar and normal between all treatments. The results showed that although the hatchability of cysts was more affected by the breeding environment, the growth of Artemia in all the unconventional water treatments was suitable compared to the control treatment, and also the morphological characteristics of Artemia were normal in all treatments. Due to the occurrence of long-term droughts in Sistan region, the only opportunity for the continuation of aquaculture, especially in recent years, lies in the use of unconventional saline water resources in this region. So, the present study provides the first evidence of relatively favorable hatching and suitable initial growth of Artemia in unconventional saline waters, especially desalination wastewater, in Sistan region and shows that cultivation Artemia is biologically possible in the unconventional waters under laboratory conditions. Conclusion: The data presented in this study generate the first useful information for the future inoculation of Artemia in unconventional waters (desalination wastewater, deep aquifer well water and well water) in Sistan, and hence domestic Artemia production in the country. However, further larger-scale laboratory work, followed by field trials, is still needed. [ABSTRACT FROM AUTHOR]

Anthropogenic habitat degradation and alien invasive species have led to the rapid decline of freshwater fish biodiversity globally. The knowledge of threatened species' embryogenesis and larval development could be important for the design of appropriate conservation measures to reverse their decline. Here, we describe the embryonic and larval development of the globally threatened Peloponnese Valencia (Valencia robertae) to inform urgently needed ex situ and in situ conservation initiatives, such as safety stock creation, conservation translocation, and population monitoring. The development of V. robertae is described from the embryonic to the juvenile stage from in vivo imaging, for the first time in detail for this species and genus. Valencia robertae's fertilised eggs are large (approximately 2 mm), spherical, macrolecithal, translucent, with negative buoyancy, filaments at the outer surface, and several oil globules. They have a long incubation period (approximately 18 days at 20 ± 1 °C) and, in laboratory conditions, a high hatching rate (84%, n = 89). Various types of chromatophores are visible in the embryo, incl. melanophores, xanthophores, and iridophores at the dorsal area of the eye and at the iris. Embryos at hatching measure approximately 5.4 mm SL (6.5 mm TL) and have well-developed caudal and pectoral fins, large eyes, and well-developed mouth; exogenous feeding starts at 24–48 h post hatching. Sequential formation of fins continues with the development of the anal and dorsal fins and is completed by the formation of the pelvic fins, at approximately 11 mm SL (25–30 days post hatching). The ecological and conservation implications of our findings are discussed. [ABSTRACT FROM AUTHOR]

Glyphosate‐based herbicides (GBH) have been commonly used in agriculture to inhibit weed growth and increase yields. However, due to the high solubility of these herbicides in water, they can reach aquatic environments, by infiltration, erosion, and/or lixiviation, affecting non target organisms. Thus, this study aimed to characterize the toxicity of GBH Roundup WG® (RWG®) during the embryonic and larval development of Danio rerio. Embryos (3 hours post fertilization, hpf–until hatching) and larvae (3 days post fertilization, dpf to 6 dpf) were exposed to concentrations of 0.065 and 6.5 mg L−1. They were evaluated for survival, hatching, spontaneous movements, heartbeat, morphology, and morphometry by in vivo photographs in microscope, cell proliferation and apoptosis by immunohistochemistry, and exploratory behavior and phototropism by video recording. Our results showed an increase in embryo and larvae mortality in those exposed to 0.065 mg L−1, as well as a reduction in spontaneous embryo movements. The larval heartbeats showed a decrease at 4 dpf in the group exposed to 0.065 mg L−1 and an increase at 5 and 6 dpf in both exposed groups. Cell proliferation was reduced in both groups exposed in embryos and only in the 0.065 mg L−1 group in larvae, while cell death increased in embryos exposed to 6.5 mg L−1. These results demonstrated the toxic effect of low concentrations of the herbicide RWG® during embryonic and larval development of non target organisms, as well as the importance of constantly reviewing acceptable limits for exposure in natural environments. [ABSTRACT FROM AUTHOR]

Embryonic development is often considered shielded from the effects of natural selection, being selected primarily for reliable development. However, embryos sometimes represent virulent parasites, triggering a coevolutionary "arms race" with their host. We have examined embryonic adaptations to a parasitic lifestyle in the bitterling fish. Bitterlings are brood parasites that lay their eggs in the gill chamber of host mussels. Bitterling eggs and embryos have adaptations to resist being flushed out by the mussel. These include a pair of projections from the yolk sac that act as an anchor. Furthermore, bitterling eggs all adopt a head-down position in the mussel gills which further increases their chances of survival. To examine these adaptations in detail, we have studied development in the rosy bitterling (Rhodeus ocellatus) using molecular markers, X-ray tomography, and time-lapse imaging. We describe a suite of developmental adaptations to brood parasitism in this species. We show that the mechanism underlying these adaptions is a modified pattern of blastokinesis--a process unique, among fish, to bitterlings. Tissue movements during blastokinesis cause the embryo to do an extraordinary "front-flip" on the yolk. We suggest that this movement determines the spatial orientation of the other developmental adaptations to parasitism, ensuring that they are optimally positioned to help resist the ejection of the embryo from the mussel. Our study supports the notion that natural selection can drive the evolution of a suite of adaptations, both embryonic and extra-embryonic, via modifications in early development. [ABSTRACT FROM AUTHOR]

Outbreaks and spread of infectious diseases are often associated with seasonality and environmental changes, including global warming. Free‐living stages of soil‐transmitted helminths are highly susceptible to climatic drivers; however, how multiple climatic variables affect helminth species, and the long‐term consequences of these interactions, is poorly understood. We used experiments on nine trichostrongylid species of herbivores to develop a temperature‐ and humidity‐dependent model of infection hazard, which was then implemented at the European scale under climate change scenarios. Intestinal and stomach helminths exhibited contrasting climatic responses, with the former group strongly affected by temperature while the latter primarily impacted by humidity. Among the demographic traits, larval survival heavily modulated the infection hazard. According to the specific climatic responses of the two groups, climate change is expected to generate differences in the seasonal and spatial shifts of the infection hazard and group co‐circulation. In the future, an intensification of these trends could create new opportunities for species range expansion and co‐occurrence at European central‐northern latitudes. [ABSTRACT FROM AUTHOR]

Quantifying how variable temperature regimes affect energy expenditure during development is crucial for understanding how future thermal regimes may impact early life survival and population persistence.Developmental cost theory (DCT) suggests that there is an optimal temperature (Topt) that minimises energy expenditure during development (the 'cost of development'). Exposure to fluctuating temperatures around an average of Topt is anticipated to increase either development time or metabolic rate. As a result, embryos will rapidly deplete yolk reserves, and consequently hatch at a smaller size or with less residual yolk to support postnatal survival and growth.Here, we studied total embryonic energy expenditure (development time and rate of CO2 production) and conversion of yolk into tissue in common wall lizards (Podarcis muralis) under three incubation treatments anticipated, based on DCT, to increase the cost of development: no variance (Topt constant, 24°C), low variance (22°C–26°C) and high variance (18°C–30°C).As predicted, we found that increasing variance around Topt increased the cost of development, despite reducing time to hatching. As a consequence, embryos on average hatched with 59% lower residual yolk reserves under high variance versus the constant incubation temperature treatment.Our results highlight how the relative temperature sensitivities of development time and metabolic rate determine the cost of development, which in turn may predict the ability of egg‐laying ectotherms to persist in variable environments. We show that DCT can provide a mechanistic framework for understanding the widespread, but often seemingly idiosyncratic, effects of fluctuating incubation temperatures on hatchling tissue and residual yolk mass. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Mixed hybridisation trials involving Clarias gariepinus (CG), Heterobranchus longifilis (HL), and Heterobranchus bidorsalis (HB) were carried out with success using Ovulin as inducing agent. The crossing was followed by an early growth trial using post-yolk sac larvae that lasted ten days. Latency periods in the two catfishes differ, with 11 hours in crosses involving female CG and 12 hours in crosses involving female HL. The fertilisation rates of eggs from the females of the two species indicate that there is no significant discernment in fertilisation (p>0.05), with values ranging from 68.38% (CG×HB) to 80.94% (HL×CG). However, rates <80% indicate egg quality problems. The hatching rate was significantly higher (p<0.05) in both C. gariepinus (62.12%) and Heterobranchus sp. (47.75%) line crosses than the hybrids. There is an additive genetic effect due to the combination of pure-line male and female gametes that elicit better growth as against survival in crosses involving C. gariepinus. The genotype for better survival is in the maternal line of H. longifilis. These culminate into heterosis for growth in hybrid CG×HB and survival in hybrid HL×CG. [ABSTRACT FROM AUTHOR]

Abstract Background Selenium is an essential mineral for poultry. The conflicting reports about its in ovo injection are the justification for the more detailed investigation. Objectives The aim of this study was to investigate the effects of in ovo injection of organic selenium on the hatching traits of broiler chickens and their performance. Methods Three hundred and twenty eggs of Ross 308 strain with an average weight of 65 g and 160 chicks were randomly divided into 4 treatment groups (each with 8 replicates of 10 eggs each for hatching parameters and 4 replicates of 10 chicks for broiler farming parameters): negative control (no injection), positive control (in ovo injection of 0.272 mL of normal saline solution) and 2 selenium treatments (in ovo injection of 2.72 or 5.44 μg of organic selenium). Injection was into the amniotic sac on the 10th day of incubation. Effects of in ovo injection on hatching and performance traits, blood parameters, immune responses, carcass characteristics, meat fatty acid profile, cecal microbial population and selenium consternation in the tibia were measured. Results Fewer chicks from the injected treatments hatched than from the negative control group (p

ABSTRACTUnderstanding the reproductive biology of birds is crucial for comprehending their natural history and implementing effective conservation practices. However, there is limited information available on the reproductive behavior of many bird species in Southern Ecuador. This manuscript contributes to the knowledge of the reproductive biology of 127 bird species from the region, providing detailed information on five species whose reproductive traits were previously undocumented (Urochroa leucura, Agriornis albicauda, Turdus maranonicus, Spinus olivaceus, and Stilpnia viridicollis), as well as reproductive data on 12 species for which information was scarce (Heliangelus viola, Chalcostigma stanleyi, Eriocnemis luciani, Coeligena iris, Megascops koepckeae, Conopophaga castaneiceps, Sclerurus obscurior, Leptasthenura andicola, Ochthoeca fumicolor, Geospizopsis unicolor, Catamenia inornata, and Sporophila castaneiventris). Furthermore, we include additional information on the reproductive biology of 110 species that have already been documented. This manuscript provides the most up-to-date inventory of the reproductive behavior of bird species in Southern Ecuador, which can aid in the development of better conservation strategies in the region.

Understanding the reproductive biology of birds is crucial for comprehending their natural history and implementing effective conservation practices. However, there is limited information available on the reproductive behavior of many bird species in Southern Ecuador. This manuscript contributes to the knowledge of the reproductive biology of 127 bird species from the region, providing detailed information on five species whose reproductive traits were previously undocumented (Urochroa leucura, Agriornis albicauda, Turdus maranonicus, Spinus olivaceus, and Stilpnia viridicollis), as well as reproductive data on 12 species for which information was scarce (Heliangelus viola, Chalcostigma stanleyi, Eriocnemis luciani, Coeligena iris, Megascops koepckeae, Conopophaga castaneiceps, Sclerurus obscurior, Leptasthenura andicola, Ochthoeca fumicolor, Geospizopsis unicolor, Catamenia inornata, and Sporophila castaneiventris). Furthermore, we include additional information on the reproductive biology of 110 species that have already been documented. This manuscript provides the most up-to-date inventory of the reproductive behavior of bird species in Southern Ecuador, which can aid in the development of better conservation strategies in the region. [ABSTRACT FROM AUTHOR]

Lack of mature male broodfish, insufficient sperm, and non-synchronized maturation times have always been a hindrance to the breeding program of Japanese koi (Cyprinus carpio var. koi) raised indoors. Therefore, it is believed that the preservation of Japanese koi sperm by short-term storage and cryopreservation could solve this problem. In this study, the appropriate diluent solution, sperm-to-diluent ratio, and storage temperature for short-term storage of Japanese koi sperm were determined, and the efficacy of the short-term stored sperm in fertilizing eggs was evaluated. Milt samples collected from sexually mature males were pooled and tested in modified calcium-free Hank's Balanced Salt Solution (CF-HBSS), modified Mahseer extender, and modified Kurokura extender at 1:1 and 1:5 ratios of sperm to diluent, respectively. Storage temperatures were tested at 4 °C and room temperature. Milt sample without diluent solution served as a control. The percentage of sperm motility was measured daily for one week. For the egg fertilization experiment, Japanese koi eggs were fertilized with sperm on the second day of short-term storage, while a freshly collected sperm sample served as a control. We found that sperm diluted 1:1 with a modified Kurokura extender and stored at 4 °C had a mean sperm motility of 76.00 ± 3.06% on the third day, compared with 54.67 ± 2.91% in the control treatment (P<0.05). Short-term stored spermatozoa showed equivalent egg fertilization ability compared to fresh spermatozoa (control) (P>0.05). In conclusion, the use of a modified Kurokura extender at a 1:1 ratio of sperm to diluent and storage at 4 °C was optimal for short-term storage of Japanese koi sperm, and these sperm still showed equivalent egg fertilization ability to freshly collected sperm after two days of storage. In addition, the current study also determined the appropriate extender solution for cryopreservation of Japanese koi sperm. [ABSTRACT FROM AUTHOR]

Within insects, corticotropin-releasing factor/diuretic hormones (CRF/DHs) are responsible for the modulation of a range of physiological and behavioural processes such as feeding, diuresis, and reproduction. Rhopr-CRF/DH plays a key role in feeding and diuresis in Rhodnius prolixus, a blood-gorging insect and a vector for human Chagas disease. Here, we extend our understanding on the role of this neurohormone in reproduction in adult female R. prolixus. Double-label immunohistochemistry displays co-localized staining of CRF-like and the glycoprotein hormone (GPA2/GPB5) subunit GPB5-like immunoreactivity in the same neurosecretory cells (NSCs) in the mesothoracic ganglionic mass (MTGM) and in their neurohemal sites in adult female R. prolixus, suggesting these peptides could work together to regulate physiological processes. qPCR analysis reveals that the transcript for Rhopr-CRF/DH receptor 2 (Rhopr-CRF/DH-R2) is expressed in reproductive tissues and fat body (FB) in adult female R. prolixus, and its expression increases post blood meal (PBM), a stimulus that triggers diuresis and reproduction. Using RNA interference, transcript expression of Rhopr-CRF/DH-R2 was knocked down, and egg production monitored by examining the major yolk protein, vitellogenin (Vg), the number and quality of eggs laid, and their hatching ratio. Injection of dsCRFR2 into adult females reduces Rhopr-CRF/DH-R2 transcript expression, accelerates oogenesis, increases the number of eggs produced, and reduces hatching rate in female R. prolixus. Downregulation of Rhopr-CRF/DH-R2 leads to an increase in the transcript expression of RhoprVg1 in the fat body and ovaries, and increases the transcript level for the Vg receptor, RhoprVgR, in the ovaries. A significant increase in Vg content in the fat body and in the hemolymph is also observed. Incubation of isolated tissues with Rhopr-CRF/DH leads to a significant decrease in transcript expression of RhoprVg1 in the fat body and RhoprVg1 in the ovaries. In addition, Rhopr-CRF/DH reduces transcript expression of the ecdysteroid biosynthetic enzymes and reduces ecdysteroid titer in the culture medium containing isolated ovaries. These results suggest the involvement of the CRF-signaling pathway in reproduction, and that Rhopr-CRF/DH acts as a gonad-inhibiting hormone in the adult female R. prolixus, as previously shown for the colocalized glycoprotein, GPA2/GPB5. [ABSTRACT FROM AUTHOR]

The results of 2020 studies of bottom cysts of brine shrimp Artemia in Lake Kuchukskoe and Lake Bolshoe Yarovoe in Altai krai (Russia) are presented. Artemia cysts were observed year round at the bottom of both lakes. The number of cysts depended on the type of bottom sediment. The biomass of bottom cysts in Lake Kuchukskoe was 154.2 t in spring, of which available and visually intact cysts constituted from 11.8 to 25.2 t. Bottom cysts of Artemia were not available for 27% of the lake area in Lake Kuchukskoe due to the high salinity of the water and salt precipitation. The viability of cysts from shallow bottom areas was 8.9% in spring. In Lake Kuchukskoe, cysts from accumulations on the coast, washed away by the runoff of melt water, played the main role in the formation of first generation of Artemia in spring. The deep water of Lake Bolshoe Yarovoe predetermined the peculiarities of the temperature regime in spring, which prevented brine shrimp cysts from ascending from the bottom if the depth exceeded 7.0 m. Significant silt deposits at the bottom of the lake were an aggressive environment for cysts, as was followed by the presence of different groups of cyst quality: visually intact, with defective chorion, gray or black. The biomass of bottom cysts in Lake Bolshoe Yarovoe was 38 934 t in autumn 2020, which exceeded the reproductive capacity of the Artemia population per year. This testified to the long-term period of accumulations of cysts at the bottom and their partly participation in the formation of the Artemia first generation in spring. In spring, the maximum hatching rate of nauplii from bottom cysts was 16% from depths exceeding 9.0 m and 26%, from a depth of 8.0 m. The viability of bottom cysts from Lake Bolshoe Yarovoe does not exceed 15% at the average; unhatched floating cysts settle back to the bottom in summer. [ABSTRACT FROM AUTHOR]

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Abstract Background In ovo application is the process of administering some nutrients or components into the egg. The main purpose of this application is to ensure that some nutrients are provided to chicks with a short incubation period. Few studies were conducted with taurine in fertile eggs; especially, no observation of hatchability and chick quality has been found. In addition, taurine has an anti‐stress impact that fights oxidative factors. Objective To assess the hatchability and chick quality after in ovo taurine administration. To determine the stress that may occur as a result of in ovo application and whether taurine has a stress‐reducing effect. Methods A total of 1200 fertile eggs from a 34‐week‐old broiler breeder (Ross 308) flock were categorized into 4 groups with 75 eggs per replicate: control (uninjected), taurine group (0.30 mL dissolved taurine in distilled water), sham control (sterile distilled water) and perforation (eggs perforated and then waxed). On day 14 of incubation, an in ovo injection was administered to the albumen. Data on hatching parameters and hepatic HSP70 levels were obtained using relevant formulas and western blotting, respectively. Results Control chicks exhibited higher hatchability than other groups, with the taurine group showing the lowest hatchability. The HSP70 levels were the highest in the perforation group compared to the control group. An increase of 21.37% in the taurine group and 83.45% in the sham control group was observed compared to the control group. Conclusions The findings suggest that in ovo application may induce increased stress, whereas taurine may have positive effects in mitigating the stress caused by in ovo application.

High larval and fry mortality has been a major challenge to the commercial culture of the African bony-tongue (Heterotis niloticus). Research indicates inadequate feeding to be a possible cause of the high mortality rates of larvae/fry grown in captivity. An experiment was conducted to first describe the developmental stages of H. niloticus eggs and larvae until schooling, 6 days after hatching (DAH), at 26°C. The morphological development, survival, growth (weight gain and length), and swimming behavior of the larvae were monitored. A follow-up feeding trial was conducted with H. niloticus fry from 6 to 27 DAH involving four treatments: feeding with Artemia nauplii; a combined feed of 50% Artemia nauplii and 50% rotifers (w/w); feeding with rotifers; and no feeding. The activities of three digestive enzymes (trypsin, lipase, and amylase) were assessed in fry exposed to the live feed treatments. At hatching, the larvae had a large, vascularized yolk sac filled with yolk platelets, which occupied approximately one-third of the total body length of the abdominal cavity. Yolk platelet reabsorption started at 1 DAH and was complete at 6 DAH. Metamorphosis was completed at 6 DAH, and schooling behavior was observed. For the feeding trial, the fry that received Artemia nauplii underwent the fastest development until 27 DAH. Similarly, the survival rate was considerably higher in fry fed with Artemia nauplii than in those that received a combination of Artemia nauplii and rotifers or only rotifers. Overall, the survival rates for fry fed with Artemia nauplii and larvae co-fed were 72.7% ± 0.9% and 41.2% ± 3.3%, respectively. Fry did not survive until 27 DAH in the rotifer-fed and unfed treatment groups. Digestive enzyme activity differed significantly (p< 0.05) between treatments and sampling dates. All digestive enzymes were detectable at the onset of mouth opening (5 DAH) and fluctuated through the 7 and 9 DAH. Lower enzyme activity was observed when the fry were subjected to starvation or the rotifer treatment. Results indicate that Artemia nauplii is the best live feed organism for H. niloticus larviculture.

Natural aquatic environments have a heterogeneous composition; therefore, simultaneous exposure to multiple contaminants is relevant and more realistic when assessing exposure and toxicity. This study examines the combinatorial effects of two compounds found ubiquitously in drinking water across the United States: glyphosate and lead acetate. Zebrafish (Danio rerio) embryos were used as a model for investigating developmental delays following controlled exposures. Six different environmentally relevant exposure concentrations of glyphosate, ranging from 0.001 to 10 ppm, and lead acetate, ranging from 0.5 to 4 ppm, were applied first as single exposures and then as co-exposures. The sublethal endpoints of hatching and coagulation were quantified to determine potencies. Results indicate that higher concentrations of the individual chemicals correlate with later hatching with correlation coefficients of 0.71 and 0.40 for glyphosate and lead acetate respectively, while the co-exposure at lower concentrations induced earlier hatching with a correlation coefficient 0.74. In addition, increased levels of coagulation and glutathione reductase activity were observed following co-exposure, as compared to the individual exposures, suggesting potential toxicological interactions. These results support the need for further work assessing the combined potencies of aquatic contaminants rather than individual exposures.

During downstream drifting in high-speed steams, semi-buoyant fish eggs can run onto rocks, boats, and other surfaces. This will result in the abrupt and severe collision shock to the fish eggs, causing damage to fish eggs and potentially leading to their death. For protection of fish stocks and river management, it is crucial to understand the impact of collision shock on their hatching and to clarify the upper threshold of collision velocity. Through an indoor free-fall experiment, we quantified the influences of collision shock on semi-buoyant fish eggs. We discovered that, when fish eggs collided with a rock at a speed of 4.4 m/s, about 70% of the eggs did not successfully hatch. Forty-five percent of the egg envelopes were broken when the collision velocity was 4.4 m/s and collided with water. Development stage, particularly when the eggs were at the cell cleavage stage, was the most susceptible factor to collision shock. Our results offer new insights for preserving fish stocks in high-speed streams and can be used to inform river management strategies.

Globodera pallida, the pale cyst nematode (PCN), is a quarantine pest of potato posing a serious threat to the Idaho potato industry. Globodera pallida only hatches in the presence of a hatching stimulus produced by a host plant or closely related species. In the absence of this hatching stimulus, G. pallida can remain viable in the soil for decades. A trap crop stimulates hatch of G. pallida but is a nonhost, which means the nematode cannot develop or reproduce. This study evaluated the trap crop potential of several solanaceous species by determining G. pallida host status and hatching effect of each species. The species under investigation included Solanum aethiopicum, S. macrocarpon, S. quitoense, S. retroflexum, and S. douglasii. All species were determined to be nonhosts of G. pallida. The most promising trap crop candidates with a hatching stimulatory effect comparable to potato were S. quitoense and S. retroflexum. Further research is needed to assess whether these species could be effective G. pallida trap crops under Idaho field conditions.

Although embryo transfer is widely applied in cattle, many of the transferred embryos do not result in pregnancy. To determine a new parameter for bovine embryo evaluation, we investigated the relationships between in vitro hatchability and embryo morphological parameters using optical coherence tomography (OCT) that we established recently. Bovine embryos were obtained from Japanese Black cattle by in vitro fertilization (IVF). The quality of the blastocysts was examined under an inverted microscope and confirmed as Codes 1–3 according to the IETS standards for embryo evaluation. The OCT images of the embryos were captured on Day 7 after IVF, and the embryos were cultured until Day 9 to determine their hatchability. During OCT, the embryos were irradiated with near-infrared light for a few minutes to obtain three-dimensional images. In total, 22 parameters were assessed for each of the 42 embryos, of which 25 hatched (H embryos) and 17 did not (NH embryos). The thickness of the trophectoderm (TE) and TE+zona pellucida (ZP) was lesser, and the volumes of the TE, ZP, blastocoel, and whole embryo and blastocoel diameter were greater in the H embryos than in the NH embryos. PCA identified that the increase in the blastocoel-related value along with the decrease in the thickness-related value of the TE and/or ZP could be indicators for evaluating the hatchability of bovine IVF embryos. These results support the idea that OCT-captured structural data of blastocyst-stage embryos can be used as a potential model to predict the quality of bovine embryos.

Introduction: Vitamin D3 is one of the important vitamins in calcium metabolism, which increases the active transport of calcium and phosphorus in the intestinal epithelium. However, the mechanism by which vitamin D3 increases the absorption of calcium and phosphorus is not fully understood. The active form of vitamin D3 or 1,25-hydroxycalciferol is transported to the nucleus of the intestinal cells. In the presence of 1, 25-hydroxycalciferol, a specific RNA is secreted from the cell nucleus, which is translated into a specific protein by the ribosomes, thereby increasing the uptake of calcium and phosphorus. The primary role of 1, 25-hydroxyvitamin D3 in vertebrates in regulating calcium homeostasis is the direct action of 1,25-hydroxyvitamin D3 on the gut, kidneys and bones by inhibiting the production of parathyroid hormone in the parathyroid glades. Vitamin C prevents stress by preventing the release of corticosteroid hormones, which can be effective for bird function, egg production and reducing mortality. In the liver, vitamin D3 is converted into 25-hydroxycalciferol, which is later converted into calciferol hydroxylase (activated by vitamin C) in the kidneys by the enzyme 25-hydroxy molecule. This metabolite increases the absorption of calcium and phosphorus from the intestinal wall and renal tubules. The aim of this experiment is therefore the effect of vitamin D3 and vitamin C on performance, egg quality and hatchability in broilers breeder hen at the end of the production period. Materials and Methods: A total of 240 broiler breeder hens and 24 cockers (Ross 308) were distributed in a 2×2 factorial arrangement including two levels of vitamin D (3500 & 5500 IU) and two levels of vitamin C (0 & 150 mg/kg) with 6 replicate pens of 10 hens and one cock each. The experiment lasted for 12 weeks (from the age of 49 to 61 weeks), and during the trial, the performance traits production and hatchability were recorded. Every 28 days 4 eggs were evaluated for internal and external quality. Results and Discussion: The results of the study showed that the main effect of vitamin D3 had a significant impact on egg weight, with higher concentrations resulting in a reduction in egg weight. However, there was no significant effect on other performance parameters. The main effect of higher concentrations of vitamin D3 was an increase in the number of hatching eggs, shell percentage, shell thickness, specific gravity of the eggs, a decrease in the percentage of egg breakage. However, this effect was not significant for other parameters. Increasing the level of 1,25 hydroxycalciferol significantly increased plasma calcium levels, which led to increased renal 1-alpha-hydroxylase activity, envelope secretion, reduced oocyte rupture, resulting in increased hatch fertility. The main effect of vitamin C significantly increased production percentage and reduced feed conversion and feed consumption per egg. However, there was no significant effect on other parameters. Addition of vitamin C significantly increased external characteristics of the eggs, including shell proportion, shell thickness, shell ash and phosphorus, number of hatching eggs, but reduced the number of broken eggs. However, there was no significant effect on internal parameters, except for yolk color. The use of vitamin C activates the enzyme 25-hydroxycholecalciferol hydroxylase to produce 1,25 hydroxycalciferol, which increases calcium absorption from the intestinal wall and reduces the number of ruptured eggs. Regarding the interaction of different levels of vitamin D3 and vitamin C, the results showed that higher levels of vitamin D3 and vitamin C increased production percentage, egg mass, number of hatching eggs, shell thickness, phosphorus and FCR. Intake in the egg removed significantly increased, but the number of broken eggs decreased. Conclusion: In general, according to the results of the present experiment, it can be concluded that the use of vitamin C in an amount of 150 mg / kg with 5500 IU of vitamin D3 can increase the production percentage, increase the mass of eggs and improve the feed conversion ratio. It can also increase shell thickness and the number of chickens produced weekly and over the period, decrease the number of broken eggs, increase the number of hatching eggs, reduce feed intake per egg and feed intake per chicken at the end of the broiler breeder production period.