Low Hatchability Research Articles

Effects of temperature and humidity on the survival and hatching response of diapausing and non-diapausing Aedes aegypti eggs

In seasonally varying environments, diapause, which is induced by a short photoperiod, favors overwintering of many insects. In Aedine mosquitoes, embryonic diapause is associated with higher survival and resistance to low temperature and humidity. Aedes aegypti, the main vector of dengue and other arboviruses, has recently expanded its distribution towards temperate regions. One of the mechanisms that might have favored this expansion in South America is the ability to induce embryonic diapause. This type of diapause has been recently discovered in populations from Argentina, associated with hatching inhibition and increased amounts of lipids in the eggs. The aim of this study was to assess the four-month survival of diapausing (D) and non-diapausing (ND) eggs stored at different humidity and temperature conditions. Two populations from the temperate region of Argentina were analyzed: one from Buenos Aires (BA), a city with a relatively mild and short winter, and another from San Bernardo (SB), a locality with a harsher and longer winter. For both populations, D and ND eggs were obtained from colonies maintained under 10:14 L:D and 14:10 L:D hours respectively. Eggs were exposed to six different conditions of humidity and temperature for 85 days. After exposure, egg survival and hatching response were analyzed. D eggs showed significantly higher survival at low humidity (both populations), and at medium and high humidity and at low temperatures (SB population). In addition, D eggs showed a significantly lower hatching response at high humidity and low temperatures, and higher proportion of not hatched eggs remaining viable after two immersions under all conditions. D eggs from SB were significantly more tolerant to low temperatures than those from BA. ND eggs from SB were significantly more tolerant to low temperatures, while those from BA were more tolerant to low humidity. Overall, the effect of diapause was a significant increase in the number of not hatched, viable embryos after immersion. Results suggest that the ability of Ae. aegypti to induce egg diapause increases the probability of successful overwintering and further expansion of its distribution range, and as a consequence the risk of arbovirus transmission might increase in temperate areas

Transcriptional profiling of the M. complexus in naked neck chickens suggest a direct pleiotropic effect of GDF7 on feathering and reduced hatchability

BackgroundThe locus for naked neck (Na) in chickens reduces feather coverage and leads to increased heat dissipation from the body surface resulting in better adaptability to hot conditions. However, the Na gene is linked to significantly lower hatchability due to an increased late embryonic mortality. It has been argued that the causative gene GDF7 may have a direct pleiotropic effect on hatchability via its effect on muscle development. Thus, the study presented here analyses the transcriptome of the hatching muscle (M. complexus) and shows how GDF7 impacts development leading to reduced hatching rates in Na chickens.ResultsUsing 12 chicken embryos (6 x wildtype (Wt) and 6 x Na) RNA was extracted from the M. complexus of each embryo and sequenced. The resulting differential expression analyses led to the discovery of 461 differentially expressed (DE) genes in the M. complexus of the experimental group. Among those, 77 genes were of uncertain function (LOC symbols), with 31 were classified as uncharacterised. The regulation of a number of pathways involved in normal embryonic development, were found to be negatively influenced by the Na genotype. Further pathways involved in cell-cell adhesion, cell signalling pathways, and amino acid (AA) metabolism/transport were also observed. GDF7 (alias BMP12), whose localised overexpression in the neck skin causes the Na/Na phenotype, was significantly overexpressed in the M. complexus of Na/Na embryos, and shows a significant increase in the number of binding sites for the transcription factor PITX2 was also observed.ConclusionIn Na chickens, GDF7 is under the control of a mutated cis-regulatory element, whose actions are known to suppress the development and distribution of feathers through the sensitizing action of retinoic acid. In this study, a number of DE genes with over 10 retinoic acid response elements (RAREs) in close proximity were observed, indicating changes to the retinol metabolism. With the understanding that the Na/Na mutation leads to increased retinoic acid activity, this indicates a high likelihood of GDF7 excerpting a direct pleiotropic effect, not just in the observed reduction in feather patterning, but also impacting the development of the M.complexus, and consequently leading to the reduced hatchability observed in birds with the Na/Na genotype.Furthermore, the enrichment of PITX2 binding sites in proximity to DE genes in the M. complexus, also indicates that muscle development is still ongoing in Na embryos. This suggests that the M. complexus is not yet fully developed, further increasing the potential for late embryonic mortality in Na chicks at hatching.

Optimizing and synchronizing Aedes aegypti colony for Sterile Insect Technique application: Egg hatching, larval development, and adult emergence rate

Mosquito Sterile Insect Technique (SIT) programs can be developed in smaller agencies through synchronization of the colony development to take advantage of the natural male early emergence. This paper examined key aspects of Ae. aegypti colony synchronization work, including egg hatching, larval development, and adult emergence to produce sufficient numbers of adult male mosquitoes within a specific timeframe for irradiation and release. Our data indicated that a relatively low percentage of males are required for colony propagation. Additional results highlighted that fresher Ae. aegypti eggs could yield as high as a 93 % hatching success than older eggs when placed under vacuum pressure in yeast infused water for 1.5 h. Eggs that were one-month old hatched (93 %) better than older eggs (0–32 %). A higher egg density in the hatching flask was correlated to a lower hatch rate, and higher larval density was related to unsynchronized pupae and delayed adult emergence. By keeping Ae. aegypti larvae at reasonable density, over 95 % of adults emerged on the first two days of emergence – indicating a high synchronicity. A standardized colony maintenance protocol therefore renders a synchronized larval development and adult male emergence which are critical in SIT programs.

The typical developmental trajectory and energy requirements of Shitou goose during the embryonic stage

Low hatchability has been a persistent challenge in the goose industry. Establishing standard atlases and comprehending embryonic development patterns are essential to improving the hatching rates of goose eggs. However, comprehensive descriptions of normal atlases, embryonic development, and energy requirements in geese are lacking. In this study, a total of 120 fertile eggs from well-known large Shitou goose were incubated using 12 nesting purebred female geese. During hatching, both the temperature of the eggshells and the weight of eggs were recorded, and daily photographs of the embryos were captured to monitor their development closely. After hatching, count the number of pores per unit area by choosing eggs without sperm, dead embryos, or abnormal shells. Furthermore, 150 Shitou goose eggs were hatched by automatic incubator, with adjustments made based on observed normal developmental stages that incubated by female geese. The eggs were carefully opened to meticulously document embryonic morphology and create a detailed development map. Measurements were taken of the eye diameter, length of the lower beak, tarsometatarsus bone, and embryo length. Subsequently, an analysis was conducted to assess the calcium, phosphorus, crude protein, and crude fat content to study the energy requirements for embryo development. As a result, the hatch rate of the incubator reached 86.67%, and the cumulative water loss rate increased with embryo age. Notably, normally developing embryos displayed a significantly higher number of pores on the eggshell surface compared to dead embryos (P < 0.05). Additionally, embryonic body length, eyeball diameter, and lower beak length exhibited continuous growth until day 19 of incubation, while tarsometatarsus length increased steadily from days 12 to 31. Liver size measurement began on the 10th day of incubation, while both leg and chest muscles showed continuous growth from the 12th day. For energy demand, the embryo primarily relied on protein sourced from the egg yolk within the first 10 days of development. Afterward, the egg yolk provided both protein and fat for embryonic growth. In summary, this study has generated a comprehensive developmental map for Shitou goose embryos, offering valuable insights into their growth and morphological changes throughout the incubation period. This map can serve as a reference for optimizing machine incubation techniques to enhance goose egg hatching rates and provide fresh perspectives on the development of geese.

Effect of different synbiotic administration methods on growth, carcass characteristics, ileum histomorphometry, and blood biochemistry of Cobb-500 broilers.

To combat enteric infections and antibiotic resistance in the poultry industry, researchers seek alternatives such as probiotics, prebiotics, and synbiotics as growth promoters. Synbiotics support probiotic growth through the supply of essential nutrients. The study's objectives were to assess the most effective delivery methods for synbiotics and evaluate their growth, histomorphometric, and hematological impacts on Cobb-500 broilers. Two studies, independently conducted, employed a completely randomized design. One hundred and eighty viable eggs in the first trial were assigned to three groups: Control (T1), sterile water (T2), and synbiotic in sterile water (T3). On the 21st day of hatching, hatchability, day-old body weights, and ileum samples for histomorphometric analysis were recorded. In the second trial, out of 500 viable eggs, 200 eggs were fed in ovo with synbiotics (PoultryStar® sol, Biomin Singapore Pte Ltd, Singapore) on 17.5 days and 300 were set aside without in ovo injection. The treatments were control (T1), in water synbiotic (T2), in ovo synbiotic (T3), combination of in ovo synbiotic and synbiotic in feed (T4), and synbiotic in feed only (T5). On 21 and 42 days, blood, ileum, and visceral organ samples were collected for laboratory analysis. Data on weight gain, daily feed intake, and water consumption were recorded for 42 days. The initial experiment's results revealed a decrease in hatchability, slight weight increase, and significant intestinal morphological changes with the use of an in ovo synbiotic. Applying synbiotic through various methods in the second trial yielded better growth results, lower blood cholesterol, and significantly longer (p < 0.05) villi on 21 days. Using the in ovo method to administer synbiotics lowered hatchability. Use of synbiotics with any method or in combination enhances growth, ileum structure, dressing yield, feed efficiency, and cholesterol levels in blood. Synbiotics enhance gut health and overall performance in broilers when used through diverse approaches.

A comparative analysis of compressive and wear failure of laser-powder bed fused Stainless Steel 316L produced with different hatch spacing in stripe and contour patterns

The selection of hatch spacing is crucial in additive manufacturing processes to produce a defect free Stainless Steel 316L (SS) components, especially in laser powder bed fusion (LPBF) process. Improper selection of hatch spacing could lead to various failure regimes (like vertical cracking, porosity, and un-melted particles) in Stainless Steel 316L (SS) component produced through laser powder bed fusion (LPBF). Further, the failure regimes have a direct impact on the hardness, compression strength, friction, and wear properties of LPBF SS components. The present study has taken substantial efforts to analyse the impact of various hatch spacing (0.08 mm, 0.10 mm. and 0.12 mm) in stripe and contour patterns, in terms of morphology, mechanical, and tribological properties of LPBF SS components. Also, the present study elucidates how variations in hatch spacing influences the features like particle fusion, crack formation, density, hardness, surface roughness, compression, and wear properties. The stripe pattern with low hatch spacing of 0.08 mm showed better particle fusion and high surface roughness; whereas the high hatch spacing has produced voids, un-melted powder particles, and cracks in the stripe and contour pattern. High densities and hardness values were attributed to the stripe patterns with more effective melting and fusing of powder particles. XRD analysis revealed the stable phase compositions across various hatch spacing with a predominant FCC crystal structure. Residual stress distribution was significantly influenced by the hatch spacing for both stripe and contour patterns. Importantly, the low hatch space leads has promoted the tensile residual stress formation and vice versa for the higher hatch spacing. Stripe patterns showed higher compression strengths with buckling and shear mode as a compression failure. The stripe pattern demonstrated a low specific wear rate (SWR) and coefficient of friction (COF) compared to the contour pattern, with respect to the various hatch spacing. Furthermore, the simulated body fluid (SBF) lubrication regime played a significant role in reducing the COF. Patches, groves, furrows, and craters demonstrated the abrasive and adhesive failure for both stripe and contour pattern, which is further detailed in the article.

Assessment of the Entomopathogenic Potential of Fungal and Bacterial Isolates from Fall Armyworm Cadavers Against Spodoptera frugiperda Caterpillars and the Adult Boll Weevil, Anthonomus grandis

Increased attention is being focused on the biological control of agricultural pests using microorganisms, owing to their potential as a viable substitute for chemical control methods. Insect cadavers constitute a potential source of entomopathogenic microorganisms. We tested whether bacteria and fungi isolated from Spodoptera frugiperda (JE Smith) cadavers could affect its survival, development, egg-laying pattern, and hatchability, as well as induce mortality in Anthonomus grandis Boheman adults. We isolated the bacteria Enterobacter hormaechei and Serratia marcescens and the fungi Scopulariopsis sp. and Aspergillus nomiae from fall armyworm cadavers and the pest insects were subjected to an artificial diet enriched with bacteria cells or fungal spores to be tested, in the case of S. frugiperda, and only fungal spores in the case of A. grandis. Enterobacter hormaechei and A. nomiae were pathogenic to S. frugiperda, affecting the survival of adults and pupae. The fungus Scopulariopsis sp. does not affect the survival of S. frugiperda caterpillars and pupae; however, due to late action, moths and eggs may be affected. Aspergillus nomiae also increased mortality of A. grandis adults, as well as the development of S. frugiperda in the early stages of exposure to the diet, as indicated by the vertical spore transfer to offspring and low hatchability. Enterobacter hormaechei and A. nomiae are potential biocontrol agents for these pests, and warrant further investigation from a toxicological point of view and subsequently in field tests involving formulations that could improve agricultural sustainability practices.

High albumen height by expression of GALNT9 and thin eggshell by decreased Ca2+ transportation caused high hatchability in Huainan partridge chicken

Hatchability could be quite different among individuals of indigenous chicken breed which might be affected by the egg quality. In this study, hatchability was individually recorded among 800 40-wk-old Huainan partridge chickens. The chickens were then divided into high and low hatchability groups (HH and LH group) with 50 birds in each group. Egg quality was further determined in the two groups. Eight birds from each group were selected for slaughtering and tissue, responsible for egg formation, collection for structure observation by staining and candidate gene expression by transcriptome analysis. The hatchability in HH was 100% and 61.18% in LH. The eggshell thickness and shell strength were significantly lower, while the albumen height and Haugh unit were significantly higher in HH group than those in LH group (P < 0.05). The magnum weight and index, and the expression of polypeptide N-acetylgalactosaminyltransferase 9 (GALNT9), which responsible for thick albumen synthesis, in HH group were also significantly higher than that of LH group (P < 0.05). Compared with the LH group, there were 702 differentially expressed genes (DEGs) in HH group, of which 402 were up-regulated and 300 were down-regulated. Candidate genes of calbindin 1 (CALB1) and solute carrier family 26 member 9 (SLC26A9), which regulate calcium signaling pathway so as to affect Ca2+ transportation, exhibited significant high and low expression, respectively, in HH group compared to those in LH group (P < 0.05). Therefore, indigenous chicken with high expression of GALNT9 in magnum to form thick albumen to provide more protein for embryo, while high CALB1 and low expression of SLC26A9 to decrease Ca2+ transportation so as to form a thinner eggshell and provide better gas exchange during embryo development.

Identification and assessment of biological activities of Gymnanthemum amygdalinum (Delile) Sch.Bip. ex Walp. collected from Bongabon, Nueva Ecija

The medicinal potential of plants encompasses a diverse array of compounds with therapeutic applications. These compounds have the potential to contribute to the development of innovative pharmaceuticals that enhance overall health. This study highlights the molecular identification, phytochemical analysis, teratogenic and cytotoxic effects of Gymnanthemum amygdalinum collected from Bongabon, Nueva Ecija. Morphological and molecular identification confirmed the identity of G. amygdalinum having 100 % similarity to their corresponding sequences. Also, G. amygdalinum exhibited secondary metabolites such as essential oils, phenols, sugars, anthraquinones, coumarins, anthrones, tannins, flavonoids, steroids, and alkaloids. The plant extract has teratogenic effects as mortality rate was observed at 1000 and 10,000 ppm, correlated with low hatchability rate at the same concentrations. These findings demonstrated the potential for anticancer, leading to further evaluation of cytotoxicity employing Artemia salina and hepatocellular carcinoma cell lines (HepG2). As a result, G. amygdalinum was found to be moderately toxic in brine shrimp lethality assay with a mortality rate of 10 ppm and higher. Similarly, it is moderately toxic in HepG2 at a median concentration of 1000 ppm and highly toxic at 4000 ppm. Collectively, G. amygdalinum extract exhibits teratogenic and cytotoxic effects and is suitable for further studies at the same or higher concentrations. Accordingly, it is recommended to proceed to the next phase of study for anticancer and antiproliferative. This study provides a scientific foundation for future research, supporting the researchers in uncovering the medicinal potentials of not only G. amygdalinum but other medicinal plants as well.

The effects of dune plant roots on loggerhead turtle (Caretta caretta) nest success.

Sand dunes are supported by the extensive root systems of dune plants that anchor the dune and protect it from erosion. While all plants that grow on the dunes support their structure, invasive plants can outcompete the native and non-native dune plants for resources such as nutrients, sunlight, and space to grow. During the summer, sea turtles lay nests on beaches and near dunes; however, their eggs and hatchlings are at risk of destruction and entrapment by dune plant root penetration. Dune plant roots can penetrate sea turtle nest cavities, thus decreasing hatch success of the eggs and emergence success of the hatchlings. We aimed to determine how plant roots impact threatened loggerhead sea turtle (Caretta caretta) nests on Casey Key, Sarasota County, Florida, USA and to assess the factors affecting plant root invasion. Specifically, we determined the effect of plant roots on loggerhead sea turtle nest success, the extent of the impact of invasive plants over non-invasive plants on nests, and if the distance from the dune (barrier) affects whether roots will penetrate the nest. From July to August 2022, we excavated 93 nests to determine the extent of root penetration and identify associated plant species. This field campaign was supported by a long-term dataset (1987-2022) on loggerhead sea turtle nesting across the region. We found that root presence decreased hatch success by 21% and emergence success by 18%, compared to nests that lacked roots within the nest chamber. Nests closer to the dune were more likely to have a higher proportion of root damage and lower hatch and emergence success. This study helps advance understanding of how native and non-native plants affect sea turtle reproductive success and helps inform coastal management aimed at conserving threatened loggerhead populations.

Impact of Aphis pomi-tending Formica rufa (Hymenoptera: Formicidae) on biological parameters of Hippodamia variegata (Coleoptera: Coccinellidae).

One of the key reasons for the poor performance of natural enemies of honeydew-producing insect pests is mutualism between ants and some aphid species. The findings demonstrated that red wood ant, Formica rufa Linnaeus (Hymenoptera: Formicidae) had a deleterious impact on different biological parameters of the lady beetle, Hippodamia variegata Goeze (Coleoptera: Coccinellidae). H. variegata laid far fewer eggs in ant-tended aphid colonies, laying nearly 2.5 times more eggs in ant absence. Ants antennated and bit the lady beetle eggs, resulting in significantly low egg hatching of 66 per cent over 85 per cent in ant absent treatments. The presence of ants significantly reduced the development of all larval instars. The highest reduction was found in the fourth larval instar (31.33% reduction), and the lowest in the first larval instar (20% reduction). Later larval instars were more aggressively attacked by ants than earlier instars. The first and second larval instars stopped their feeding and movement in response to ant aggression. The third and fourth larval instars modified their mobility, resulting in increased ant aggression towards them. Adult lady beetles were shown to be more vulnerable to ant attacks than larvae. However, H. variegata adults demonstrated counterattacks in the form of diverse defensive reaction behaviours in response to F. rufa aggression.

Fine-Tuning Melt Pools and Microstructures: Taming Cracks in Powder Bed Fusion—Laser Beam of a non-weldable Ni-base Superalloy

Powder Bed Fusion – Laser Beam (PBF-LB) of high γ’ strengthened Ni-base superalloys, such as CM247LC, is of great interest for high temperature applications in gas turbines. However, PBF-LB of CM247LC is challenging due to the high cracking susceptibility during PBF-LB processing (solidification cracking) and heat treatment (strain age cracking, mostly caused by residual stresses). This study focuses on understanding the impact of process parameters on microstructure, residual stresses and solidification cracking. Laser power (P), speed (v) and hatch spacing (h) were varied while the layer thickness (t) was fixed. The melt pool size and shape were found to be key factors in minimizing solidification cracking. Narrower and shallower melt pools, achieved using a low line energy density (LED = P/v ≤ 0.1 J/mm), gave low crack densities (0.7 mm/mm2). A tight hatch spacing (h = 0.03 mm) resulted in reduced lack of fusion porosity. Electron backscatter diffraction investigations revealed that parameters giving finer microstructure with 〈100〉 crystallographic texture had low crack densities provided they were processed with a low LED. Atom probe tomography elucidated early stages of spinodal decomposition in the as-built condition, where Cr and Al cluster separately. The extent of spinodal decomposition was found to be affected by the LED and the hatch spacing. Samples with low LED and small hatch spacing showed higher degrees of spinodal decomposition. X-ray diffraction residual stress investigations revealed that the residual stress is proportional to the volumetric energy density (VED = P/(v. h. t)). Although low residual stresses can be achieved by using low VED, there is a high risk of lack of fusion. Hence, other parameters such as modified scan strategy, build plate pre-heating and pulsed laser mode, must be further explored to minimize the residual stresses to reduce the strain age cracking susceptibility.

Overexpression of miR-927-5p suppresses stalky expression and negatively reduces the spermatid production in Zeugodacus cucurbitae.

The melon fly, Zeugodacus cucurbitae Coquillett, is one of the major pests attacking Cucurbitaceae crops. Identifying critical genes or proteins regulating fertility is essential for sustainable pest control and a research hotspot in insect physiology. MicroRNAs (miRNAs) are short RNAs that do not directly participate in protein translation, but instead function in post-transcriptional regulation of gene expression involved in male fertility. We found that miR-927-5p is highly expressed in the testes and investigated its function in spermatogenesis in Z. cucurbitae. Fluorescence in situ hybridization (FISH) showed miR-927-5p in the transformation and maturation region of the testis, and overexpression of miR-927-5p reduced the number of sperms by 53%. In continuation, we predicted 12 target genes of miR-927-5p using bioinformatics combined with transcriptome sequencing data, and found that miR-927-5p targets the new gene Stalky in insects, which was validated by quantitative real-timePCR, RNA pull-down and dual luciferase reporter assays. FISH also confirmed the co-localization of miR-927-5p and the transcript Stalky_1 in the testis. Moreover, silencing of Stalky_1 by RNA interference reduced the number of sperms by 32% and reduced sperm viability by 39% in physiologically mature male adults. Meanwhile, the silencing of Stalky_1 also resulted in low hatchability. Our work not only presents a new, so far unreported mechanism regulating spermatogenesis by miR-927-5p targeting a new unknown target, Stalky, which is providing new knowledge on the regulatory network of insect spermatogenesis, but also lays a foundation for the development of SIT against important tephritid fly pests. © 2024 Society of Chemical Industry.

Brood protection is essential but not sufficient for population survival of lapwings Vanellus vanellus in central Switzerland

Lapwing are among those ground nesting bird species that suffered strong population declines following agricultural intensification in many parts of Europe. The key problem appears to be a low breeding success which, depending on the situation, may be due to predation of eggs and chicks, starvation of chicks especially during dry conditions, agricultural activities leading to direct killings, and suboptimal breeding habitat. Here, we report on a population of 40–60 lapwing breeding pairs in an intensively cultivated arable landscape in central Switzerland, where protection from farming activities, implementation of special lapwing habitat and nest fencing to exclude terrestrial predators (mainly red fox) started in 2005 and is still ongoing. Chicks were ringed and families subsequently observed every 2–3 days. Hatching success for fenced nests built before May was high. Low hatching success was observed in unfenced nests due to high predation rates and in late nests due to abandonment by the female when the vegetation was growing too tall (e.g. maize). Regularly, chicks disappeared during the night shortly after hatching. Most likely many of them first left the fence and were predated outside. Our observations from a fenced field with wet soils and puddles suggest that lapwing may produce sufficient offspring if predation can be reduced and if large enough areas with suitable habitat are available.

Carvacrol in ovo delivery optimization and flow dynamics in broiler chicken eggs

In ovo delivery of carvacrol, the primary active compound in oregano essential oil (OEO) has the potential to enhance gut development in broilers. This study aimed to optimize in ovo application of OEO by investigating day and site of injection and delivery of carvacrol to different embryonic tissues. In Experiment 1, 2 d of injection (embryonic day (E) 12 or 17.5) and 3 sites of injection for OEO (air cell, amniotic fluid, or yolk) were evaluated based on hatchability and posthatching performance. Experiment 2 aimed to examine the impact of combining OEO with the nonionic surfactant polysorbate 80 (p80) at ratios to carvacrol of 0:0, 0:1, 0.5:1, and 1:1 on carvacrol concentration in amniotic fluid, blood, and yolk. The concentration of carvacrol was measured at 3, 6, and 9 h after OEO injection either without (0:1) or with (1:1) p80. Injection of OEO on E12 led to a significant lower hatchability compared to E17.5 (P ≤ 0.01; Δ = 9.2%). Injecting OEO into the air cell, amniotic fluid, or yolk at E17.5 did not significantly affect hatchability and posthatching performance. The highest concentrations of carvacrol found in egg tissues were observed when injected together with surfactant at the 1:1 ratio (P ≤ 0.001; 14.45 µM, 16.64 µM, and 124.82 µM, for air cell, amniotic fluid, and yolk, respectively) compared to the 0:0, 0:1 or 0.5:1 ratios. Carvacrol was highest in the amniotic fluid and blood at the first time point (3 h postinjection) and decreased afterward (P ≤ 0.001), whereas the concentration in yolk remained elevated up to 9 h postinjection. In conclusion, the optimization of the in ovo delivery of carvacrol resulted in that early injection (E12) had negative effects on hatchability and should be avoided. The findings also suggest that using a nonionic surfactant was crucial for an effective delivery of carvacrol in ovo and the migration from amniotic fluid to yolk within 3 h. In addition, carvacrol's persistence in yolk may serve as a route for delivery into the gastrointestinal tract via the yolk stalk during the peri-hatching phase, potentially influencing gut development.

Efeito do tempo de estocagem pré-incubação e adição de maltodextrina in ovo sobre os parâmetros de incubação em marrecos de Pequim

ABSTRACT: The objectives of this study were to assess the effects of i) pre-incubation storage time of Pekin duck eggs on incubation parameters and ii) different levels of in ovo injection with maltodextrin on Pekin duckling weight. The study was divided into two experiments using hatching eggs of Cherry Valley SM2 hens with egg-laying ages between 31 and 40 weeks. In experiment I, 8,820 eggs were subjected to different periods of pre-incubation storage (one-seven days). For experiment II, 120 eggs weighing between 75 and 85 g were selected and inoculated with 250 µL of 0.75% saline solution with different concentrations of maltodextrin treatments (0%, 1.5%, 3.0%, and 4.5%). In relation to pre-incubation storage time, eggs stored for one day had lower hatching and hatchability rates and higher duckling mortality rates than eggs stored for longer periods (P &lt; 0.05). In ovo injection with 3.0% maltodextrin in 0.75% saline solution significantly increased the hatching weight of Pekin ducklings (53.62 g) compared to that by other study treatments (P &lt; 0.05). Therefore, Pekin duck eggs produced between 31 and 40 weeks of life may be stored between two and seven days without affecting hatchery productivity parameters. The hatching weight of Pekin ducks may be improved with in ovoinjection with 3.0% maltodextrin in 0.75% saline solution.

Effect ofcarica papayaleaf extract toward hatching and survival rate of nilem fish (Osteochilus hasselti) larvae

One of the problems in nilem fish (Osteochilus hasselti) harvesting is the unfulfilled availability of seed that is caused by low hatchability of eggs and larvae survival as well as high larvae abnormalities due to attacks by microorganisms such as fungi and bacteria. Papaya leaf was known as one alternative to increase the egg’s hatching rate because it has antifungal and antibacterial bioactive compounds. This study aimed to determine the effect of papaya leaf extract on egg hatchability, larvae abnormalities, and larvae survival. This study used an experimental method using Completely Randomized Design (CRD) with 4 treatments and 4 repetitions. The treatment doses of the papaya leaf extract that were tested were control (A), 0.75 mg/L (B), 1 mg/L (C), and 1.25 mg/L (D). The results showed that the addition of papaya leaf extract had a significant effect (P&lt;0.05) on egg hatchability, larvae abnormalities, and survival rate ofOsteochilus hasseltilarvae. The hatching rate results for each treatment were 76.50% (A), 79.50% (B), 83.50% (C), and 87.25% (D). The results of larvae abnormalities showed 9.16% (A), 7.24% (B), 5.09% (C), and 4.30% (D). Meanwhile, the results of larvae survival showed 73.87% (A), 76.13% (B), 77.25% (C), and 80.55% (D). Treatment D (1.25 mg/L) was the best treatment in this study, resulting in egg hatchability of 87.25%, larvae abnormality of 4.30%, and larvae survival of 80.55%.

Comparative study on the gamete quality, artificial propagation and larval development of common goldfish, shubunkin, black moor, and oranda variants of goldfish (Carassius auratus)

Due to the origin and diversity of goldfish, it is a suitable model organism to investigate the effect of artificial selection on reproduction and larval development. In the present study, four, well-known variants of goldfish (common goldfish, shubunkin, black moor, oranda) with considerable phenotypical differences were compared within the framework of gamete quality assessment, propagation trial, larvae rearing and morphology assessment. In our first experiment, sperm concentration, sperm volume per fish (sperm volume) and volume of sperm per kg of body weight of males did not differ significantly between the variants. Concerning the measured Computer-Assisted Sperm Analysis (CASA) system parameters, shubunkin and oranda had significantly higher progressive motility (pMOT, %) than black moor. Tendencies in female gamete production were observed in the second experiment, despite not all cases displaying significant differences. For pseudo-gonadosomatic index (PGSI, %), higher values were recorded for the globular-bodied goldfish, while the contrary was seen for the number of eggs per gram. Out of the four variants, a significantly higher fertilization rate was determined for oranda, while a significantly lower hatch rate was calculated for black moor. In the third experiment, a significant difference in the body length of freshly hatched larvae was observed between common goldfish and shubunkin during larvae rearing. However, at 3 days post-hatching (dph), shubunkin and oranda had a significant difference in this parameter. At 10 dph, common goldfish and shubunkin had significantly lower body weights than black moor and oranda. Moreover, developmental variances between common goldfish and black moor were observed in larvae morphology. At the end of larvae rearing, a significantly higher survival rate was recorded for common goldfish than for shubunkin and oranda. Even though not all parameters show considerable differences between the variants, black moor is far behind the others in terms of hatching rate and morphological abnormalities.Thousands of years of artificial selection have had a noticeable mark on the reproductive capacity and larval development of goldfish variants studied. Our results may contribute to further research on the impact of artificial selection on reproductive biology.

Pheasant hatchability and physicochemical features of egg and extra-embryonic structures depending on eggshell color

The study aimed to analyze the biological value of eggs and extra-embryonic structures affecting pheasant hatchability depending on the eggshell's color. Eggs (1,415) from 62-wk-old pheasants were used. The quality of fresh blue (BL), brown (BR), and green (G) eggs were analyzed. Incubation lasted for 25 d. Thick albumen (d 0, 1, 7, 14), amniotic fluid (d 14, 18), and the yolk (d 0-14) were collected. The pH, viscosity, lysozyme activity, crude protein (CP) content in albumen and amnion, pH, vitelline membrane strength, and fatty acids (FA) content in the yolk were performed. The lowest hatchability was in the BL group, and the highest was in the G group. BL group showed lower eggshell thickness and strength and higher egg weight. In thick albumen and amniotic fluid, the pH decreased with the incubation. In the yolk, there was an increasing trend (P = 0.015), with a decrease on d 18 (P < 0.001). The vitelline membrane strength decreased after 1 d of incubation, excluding BR eggs (P < 0.001). Thick albumen viscosity was higher on d 14 in the G group than in other dates and groups, the lowest in amniotic fluid, and slightly higher in BL and BR eggs. On d 18, amniotic fluid viscosity increased (P < 0.001). The lowest viscosity was indicated in BL eggs (P < 0.001). The lysozyme activity in thick albumen on d 14 was the highest (uniquely in BR and G groups), and the lowest values were found in amniotic fluid on d 14; after four d, the activity increased (P < 0.001). The CP content was higher in the BL group on d 14. In amnion, on d 14, the CP content was the lowest (<1%) and increased on d 18 (P < 0.001). There was a higher FA content (especially UFA) in the G group and a decrease in FA content after d 14 (P < 0.001). It was found that eggs with green eggshells have the highest biological value, and blue eggs are the least useful for incubation.

Deficiency of Brummer lipase disturbs lipid mobilization and locomotion, and impairs reproduction due to defects in the eggshell ultrastructure in the insect vector Rhodnius prolixus

Rhodnius prolixus is a hematophagous insect, which feeds on large and infrequent blood meals, and is a vector of trypanosomatids that cause Chagas disease. After feeding, lipids derived from blood meal are stored in the fat body as triacylglycerol, which is recruited under conditions of energy demand by lipolysis, where the first step is catalyzed by the Brummer lipase (Bmm), whose orthologue in mammals is the adipose triglyceride lipase (ATGL). Here, we investigated the roles of Bmm in adult Rhodnius prolixus under starvation, and after feeding. Its gene (RhoprBmm) was expressed in all the analyzed insect organs, and its transcript levels in the fat body were not altered by nutritional status. RNAi-mediated knockdown of RhoprBmm caused triacylglycerol retention in the fat body during starvation, resulting in larger lipid droplets and lower ATP levels compared to control females. The silenced females showed decreased flight capacity and locomotor activity. When RhoprBmm knockdown occurred before the blood meal and the insects were fed, the females laid fewer eggs, which collapsed and showed low hatching rates. Their hemolymph had reduced diacylglycerol content and vitellogenin concentration. The chorion (eggshell) of their eggs had no difference in hydrocarbon amounts or in dityrosine crosslinking levels compared to control eggs. However, it showed ultrastructural defects. These results demonstrated that Bmm activity is important not only to guarantee lipid mobilization to maintain energy homeostasis during starvation, but also for the production of viable eggs after a blood meal, by somehow contributing to the right formation of the egg chorion.