In ovo betaine and heat acclimation affect hatching results, growth performance and immunity of the broilers under cyclic heat stress.

This study investigated the effects of in ovo betaine and thermal manipulation during incubation on growth performance, and some immune parameters of broilers under cyclic heat stress (CHS). Eggs were divided into 5 groups and incubated at 1) 37.8 °C and 60% relative humidity (Control incubation and not-injected, CI); 2) eggs were incubated at CI and in ovo betaine injected into yolk sac on d 11 (E11) (CI + In ovo); 3) eggs were exposed to 38.8 °C for 8 h between 10 and 18d of incubation (heat acclimation, HA); 4) eggs were incubated at HA and in ovo betaine applied (HA + In ovo); 5) positive control: eggs were incubated at CI and injected with saline. Hatched chicks were raised under standard management conditions until 21 d, between 21 and 42 d half of the chickens in each incubation treatment were kept either at optimum (OPT) or at CHS. In ovo and HA did not affect hatching performance. In ovo increased thymus and spleen weights of chicks. Serum IgG was higher in HA + In ovo chicks. From d 7 to 21, in ovo chicks were heavier body weights, consumed more feed, and better feed conversion than those from CI. The body weights of HA chickens were similar in OPT and CHS on d 28 and 35. CHS reduced the body weight of CI chickens which was compatible with their feed consumption. Moreover, feed intake of HA + In ovo chickens exposed to CHS was higher than those not injected indicating that HA + In ovo enhanced thermoregulation of chickens under CHS.

Swimming through sand: using accelerometers to observe the cryptic, pre-emergence life-stage of sea turtle hatchlings.

Animals that hatch within a subterranean nest, such as turtle hatchlings, expend some of their limited energy reserves digging out through sand or soil to reach the surface. In sea turtles, this emergence process can take the hatchlings 3-7 days. However, we have a poor understanding of this process as it is difficult to observe what is occurring underground. Here, we utilize a novel method to characterize digging-out behaviour: affixing an accelerometer directly to newly hatched green turtles (Chelonia mydas) to record movement until nest emergence. Our data revealed that buried hatchlings maintained a head-up orientation but did not move in the expected left and right swaying motion associated with alternating limb crawling. Rather, they moved using dorsal-ventral heaving and pitching as if swimming vertically through the sand to the surface. Movement activity was irregular and brief, interspersed by many short periods of inactivity, mostly lasting less than 10 min. The first 24 h of head-up activity displayed no diel patterns, but the last 24 h prior to emergence involved more intense movement during night-time hours compared with daytime hours. Thus, our results add valuable new insight, and in some cases change previous assumptions, regarding the digging behaviours during the egg-to-emergence life stage in sea turtles.

Interactions between broiler parent stock age and egg pre-incubation duration: effects on embryo development, hatchability, day-old chick weight, and yolk sac weight.

Egg storage is a common practice in commercial hatcheries, but prolonged storage can negatively impact hatchability, causing a significant problem for the poultry industry. Repeated pre-incubation could mitigate the decline depending on the age of the parent stock. The study investigated the interactions between parent stock age (30, 45, and 58 weeks) and repeated pre-incubation on the hatchability and embryo development of 15-day stored eggs from Ross 308 parent stock. Three different pre-incubation durations were employed during storage: no pre-incubation and twice at the 5th and 10th days of egg storage for either 4 or 8 h. For each parent stock age, 3 600 eggs collected on the same day from the same parent stock were used for hatchability assessment. The duration of pre-incubation was determined as the eggshell temperature increased from 28 °C to a maximum of 35 °C and then cooled to 28 °C; the persistency at 35 °C was either 1 or 4 h for the total pre-incubation period. The hatchability of both set and fertile eggs and early, middle, and late embryonic mortality depended on the parent stock's age (P < 0.001). Pre-incubation alone did not have any impact on hatchability. Conversely, a significant interaction was observed between parent stock age and pre-incubation duration on the hatchability of fertile eggs (P = 0.001). At 30 weeks of parent stock age, both durations of pre-incubation positively influenced the hatchability. At 45 weeks of parent stock age, pre-incubation length had no effect on hatchability. At 58 weeks of parent stock age, a longer pre-incubation period, 2 × 8 h, was associated with decreased hatchability. Early embryonic mortality was not influenced by pre-incubation. However, a significant interaction was observed (P = 0.003). At 30 weeks of parent stock age, both short and long lengths of pre-incubation were associated with a decrease in early embryonic mortality. However, at 45 and 58 weeks, pre-incubation did not significantly affect early embryonic mortality. Additionally, longer pre-incubation periods significantly increased middle mortality compared to untreated eggs (P = 0.035). The median of embryo development for untreated eggs was the same across all ages (stage 10). In the older parent stock (45 and 58 weeks), repeated pre-incubation increased variability in embryo development, while in the younger parent stock, repeated pre-incubation decreased variability in embryo development. In conclusion, the duration and the frequency of pre-incubation should be specified based on the age of the parent stock.

Impact of different mating ratios of broiler breeder on reproductive performance during post moult phase.

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.

Effects of Light and Water Agitation on Hatching Processes in False Clownfish Amphiprion ocellaris.

False clownfish (Amphiprion ocellaris) employ a hatching strategy regulated by environmental cues, wherein parents provide water flow to encourage embryos to hatch after sunset on the hatching day. Despite previous studies demonstrating the necessity of complete darkness and water agitation for hatching, the regulatory mechanisms underlying these environmental cues remain elusive. This study aimed to investigate how darkness and water agitation affect the secretion of hatching enzymes and the hatching movements of embryos in false clownfish. Assessment of chorion digestion and live imaging of Ca2+ in hatching glands using GCaMP6s, a Ca2+ indicator, revealed that darkness stimulation triggers the secretion of hatching enzymes by increasing Ca2+ levels in hatching gland cells. On the other hand, water agitation primarily stimulated hatching movements in embryos, which led to the rupture of their egg envelopes. These results suggest that changes in light environments following sunset induce embryos to secrete hatching enzymes and that water agitation provided by parents stimulates hatching movements. These responses to environmental cues, light and water agitation, contribute to the rapid and synchronous hatching in false clownfish.

Dose rate dependent genotoxic and metabolic effects predict onset of impaired development and mortality in Atlantic salmon (S. salar) embryos exposed to chronic gamma radiation.

Release of radionuclides to the environment from either nuclear weapon and fuel cycles or from naturally occurring radionuclides (NORM) may cause long term contamination of aquatic ecosystems and chronic exposure of living organisms to ionizing radiation, which in turn could lead to adverse effects compromising the sustainability of populations. To address the effects of chronic ionizing radiation on the development of fish, Atlantic salmon embryos were exposed from fertilization until hatching (88 days, 550 day-degree) to dose rates from 1 to 30 mGy·h-1 gamma radiation (60Co). The lowest adopted dose rate was similar to the highest doses measured in some water bodies right after the Chernobyl accident (1 mGy·h-1), however, well above current environmentally realistic scenarios (20 µGy·h-1), or the threshold assumed for significant effects on fish population (40 µGy·h-1). Dose dependent effects were observed on survival, hatching, morbidity, DNA damage, antioxidant defenses, and metabolic status. Histopathological analysis showed dose rate dependent impairment of eye and brain tissues development and establishment of epidermal mucus cell layers accompanied by increased DNA damage at doses ≥1.3 Gy (dose rates ≥1 mGy·h-1). At ≥32.8 Gy (dose rates ≥20 mGy·h-1) deformities and developmental growth defects resulted in respective 46 and 95 % pre-hatch mortality. The 10 mGy·h-1 exposure (≥ 12 Gy total dose) caused significantly increased DNA damage, impaired eye development, and both premature and delayed hatching, while no deformities or effect on survival were observed. We observed a dose rate dependent reduction from dose rate ≥ 20 mGy·h-1 (≥ 27 Gy total dose) on antioxidant SOD, catalase and glutathione reductase enzyme activities. The reduction of antioxidant enzyme activities was in line with observed developmental delay and disturbance to time of hatching. Metabolomic profiles showed a clear shift at dose rates ≥10 mGy·h-1 (≥ 12 Gy total dose) in pathways related to oxidative stress, detoxification, DNA damage and repair. Due to gamma radiation exposure, a switch of central metabolism from glycolysis, citric acid cycle and lactate production towards pentose phosphate pathway indicated a rewiring mechanism for increased production of reductive equivalents to maintain redox homeostasis at the expense of energy output and thus embryonic development.

Global change and premature hatching of aquatic embryos.

Anthropogenically induced changes to the natural world are increasingly exposing organisms to stimuli and stress beyond that to which they are adapted. In aquatic systems, it is thought that certain life stages are more vulnerable than others, with embryos being flagged as highly susceptible to environmental stressors. Interestingly, evidence from across a wide range of taxa suggests that aquatic embryos can hatch prematurely, potentially as an adaptive response to external stressors, despite the potential for individual costs linked with underdeveloped behavioural and/or physiological functions. However, surprisingly little research has investigated the prevalence, causes and consequences of premature hatching, and no compilation of the literature exists. Here, we review what is known about premature hatching in aquatic embryos and discuss how this phenomenon is likely to become exacerbated with anthropogenically induced global change. Specifically, we (1) review the mechanisms of hatching, including triggers for premature hatching in experimental and natural systems; (2) discuss the potential implications of premature hatching at different levels of biological organisation from individuals to ecosystems; and (3) outline knowledge gaps and future research directions for understanding the drivers and consequences of premature hatching. We found evidence that aquatic embryos can hatch prematurely in response to a broad range of abiotic (i.e. temperature, oxygen, toxicants, light, pH, salinity) and biotic (i.e. predators, pathogens) stressors. We also provide empirical evidence that premature hatching appears to be a common response to rapid thermal ramping across fish species. We argue that premature hatching represents a fascinating yet untapped area of study, and the phenomenon may provide some additional resilience to aquatic communities in the face of ongoing global change.

Enhancing predictive models for egg donation: time to blastocyst hatching and machine learning insights.

BACKGROUND: Data sciences and artificial intelligence are becoming encouraging tools in assisted reproduction, favored by time-lapse technology incubators. Our objective is to analyze, compare and identify the most predictive machine learning algorithm developed using a known implantation database of embryos transferred in our egg donation program, including morphokinetic and morphological variables, and recognize the most predictive embryo parameters in order to enhance IVF treatments clinical outcomes. METHODS: Multicenter retrospective cohort study carried out in 378 egg donor recipients who performed a fresh single embryo transfer during 2021. All treatments were performed by Intracytoplasmic Sperm Injection, using fresh or frozen oocytes. The embryos were cultured in Geri® time-lapse incubators until transfer on day 5. The embryonic morphokinetic events of 378 blastocysts with known implantation and live birth were analyzed. Classical statistical analysis (binary logistic regression) and 10 machine learning algorithms were applied including Multi-Layer Perceptron, Support Vector Machines, k-Nearest Neighbor, Cart and C0.5 Classification Trees, Random Forest (RF), AdaBoost Classification Trees, Stochastic Gradient boost, Bagged CART and eXtrem Gradient Boosting. These algorithms were developed and optimized by maximizing the area under the curve. RESULTS: The Random Forest emerged as the most predictive algorithm for implantation (area under the curve, AUC = 0.725, IC 95% [0.6232-0826]). Overall, implantation and miscarriage rates stood at 56.08% and 18.39%, respectively. Overall live birth rate was 41.26%. Significant disparities were observed regarding time to hatching out of the zona pellucida (p = 0.039). The Random Forest algorithm demonstrated good predictive capabilities for live birth (AUC = 0.689, IC 95% [0.5821-0.7921]), but the AdaBoost classification trees proved to be the most predictive model for live birth (AUC = 0.749, IC 95% [0.6522-0.8452]). Other important variables with substantial predictive weight for implantation and live birth were duration of visible pronuclei (DESAPPN-APPN), synchronization of cleavage patterns (T8-T5), duration of compaction (TM-TiCOM), duration of compaction until first sign of cavitation (TiCAV-TM) and time to early compaction (TiCOM). CONCLUSIONS: This study highlights Random Forest and AdaBoost as the most effective machine learning models in our Known Implantation and Live Birth Database from our egg donation program. Notably, time to blastocyst hatching out of the zona pellucida emerged as a highly reliable parameter significantly influencing our implantation machine learning predictive models. Processes involving syngamy, genomic imprinting during embryo cleavage, and embryo compaction are also influential and could be crucial for implantation and live birth outcomes.

High thermal tolerance of egg clutches and potential adaptive capacity in green turtles.

Climate warming threatens sea turtles, among other effects, because high temperatures increase embryo mortality. However, not all species and populations are expected to respond the same way because they could have different thermal tolerances and capacities to adapt. We tested the effect of incubation temperature on egg mortality in a population of green turtles (Chelonia mydas) previously suggested to be less affected by extreme climatic events than others. We (1) assessed the relationship between temperature and hatching success, (2) defined an optimal range of temperatures that maximized hatching success and (3) assessed the variability in the response to temperature among clutches laid by different mothers, which could allow adaptation. Hatching success was consistently high in green turtle clutches with a skew toward high values, with 50 % of clutches having a success above 94 %. Yet, it was mildly affected by temperature, declining at both low and high temperatures. The optimal range of mean incubation temperatures was between ~30.5 °C and 32.5 °C. Current mean temperatures (31.3 °C) fall within the middle of the optimal range, indicating a potential resilience to further rises in mean nest temperature. Hatching success was best described by nest temperature and the interaction between female identity and temperature. This last predictor indicated a variability in thermal tolerance among clutches laid by different mothers and therefore, a capacity to adapt. The studied population of green turtles seems to be less vulnerable than others to climate warming. Understanding how different populations could respond to increasing temperatures could help complete the picture on the potential effects of climate change on sea turtles.

RhoprCAPA-2 acts as a gonadotropin regulating reproduction in adult female, Rhodnius prolixus.

CAPA peptides play diverse roles in insects, modulating muscle contraction, regulating fluid balance, and reproduction. In Rhodnius prolixus, a hematophagous insect and a vector for human Chagas disease, three CAPA peptides are encoded by the capability gene, including RhoprCAPA-1, RhoprCAPA-2, and RhoprCAPA-PK-1. RhoprCAPA-2 is an anti-diuretic hormone in R. prolixus. Here, we explore the involvement of RhoprCAPA-2 in reproduction in adult female R. prolixus. Double-label immunohistochemistry reveals co-localization of RhoprCAPA-2-like and the glycoprotein hormone (GPA2/GPB5) subunit GPB5-like immunoreactivity in neurosecretory cells in the mesothoracic ganglionic mass and in their neurohemal sites, suggesting these peptides can be co-released to regulate physiological processes. qPCR analysis reveals changes in transcript expression levels of the RhoprCAPA receptor (CAPAR) in the fat body and reproductive tissues after feeding in adult female R. prolixus. RNA interference-mediated knockdown of CAPAR transcript decreases egg production and reduces hatching rate and survival rate in female R. prolixus. Downregulation of CAPAR decreases vitellogenin RhoprVg1 transcript expression in the fat body and deceases its receptor RhoprVgR transcript level in the ovaries; accompanied by a reduction in vitellogenin content in the fat body and hemolymph. Incubation of fat body and ovaries in vitro with RhoprCAPA-2 increases RhoprVg1 transcript expression in the fat body, vitellogenin content in the fat body culture medium, and increases RhoprVgR transcript in the ovaries. These findings implicate the CAPA signaling pathway in reproduction, with RhoprCAPA-2 acting as a gonadotropin in adult female R. prolixus.

Research Note: Effects of on-farm and hatchery hatching on broiler performance, intestinal lesions, and immune response during a subclinical necrotic enteritis challenge.

The effects of traditional and on-farm hatching systems on broiler performance and health under a subclinical necrotic enteritis (NE) challenge were evaluated in this study. A 2×2 factorial study explored the effects of place of hatch (on-farm hatched [OFH] vs. hatchery hatched [HH]) and NE challenge (nonchallenged vs. challenged) on broilers. Cobb 500 eggs (∼E19) were acquired from a commercial hatchery; 840 eggs were placed in pens on clean shavings in prewarmed floor pens and allowed to hatch out, while 927 eggs were placed in a hatcher set under standard practices. On day (d) of hatch, all chicks were weighed and randomly distributed to 4 treatments (8 replicate pens each and 30 birds/pen). The OFH birds were placed immediately after sorting while HH birds were placed back in the hatcher overnight to simulate commercial hatchery procedures. After placing HH birds, feed and litter in the challenge group pens were sprayed with a live oocyst coccidia vaccine as a predisposing factor to NE. The small intestines of 3 male chicks per pen were scored for NE lesions (n = 24) on d 8 (peak NE challenge) and jejunal samples were collected from 1 bird per pen for RNA extraction and qPCR on d 8 and d 14. Data were analyzed using JMP Pro17 and significance between treatments was identified by LSD (P ≤ 0.05). Regardless of the hatching system, the subclinical NE challenge caused a significant reduction in average daily gain (ADG) and average daily feed intake (ADFI), and increased feed conversion ratio (FCR) until d 28 (P ≤ 0.05). Moreover, OFH birds exhibited significantly better growth (P ≤ 0.05) through d 28 but had similar performance to HH birds by d 42. There were no significant differences in NE lesion scores between HH and OFH groups. In conclusion, OFH system resulted in better broiler performance compared to HH system under both no-challenge and challenge conditions during the starter and grower periods. This practice may hold potential for further exploration by the industry as an alternative to traditional hatching, aiming to improve the welfare and productivity of broilers.

Chronic and acute thermal stressors have non-additive effects on fertility.

Climate change is driving both higher mean temperatures and a greater likelihood of heatwaves, which are becoming longer and more intense. Previous work has looked at these two types of thermal stressors in isolation, focusing on the effects of either a small, long-term increase in temperature or a large, short-term increase in temperature. Yet, a fundamental gap in our understanding is the combined effect of chronic and acute thermal stressors and, in particular, its impact on vital processes such as reproduction. Here, we investigated the independent and interactive effects of higher constant temperatures and short-term heatwave events on reproductive success and offspring fitness in an insect study system, the burying beetle Nicrophorus vespilloides. We found a substantial reduction in key fitness traits (fecundity, hatching success and offspring size) after exposure to both a heatwave and higher constant temperatures, but not after exposure to only one of these thermal stressors. This indicates that the effects of chronic and acute thermal stressors are amplified when they act in combination, as is very likely to occur in natural populations. Our findings, therefore, suggest that, by not considering the potential multiplicative effects of different types of thermal stressors, we may be underestimating the effects of climate change on animal fertility.

Adverse effects of thimerosal on the early life stages of zebrafish.

Thimerosal (THI) is an organic mercury compound that is widely used in drugs, vaccines and antibacterial products. Its extensive production and use have resulted in significant environmental contamination, posing a considerable threat to aquatic life. However, the knowledge of the toxicity of THI to aquatic organisms is still insufficient. In this study, we conducted a 5-day THI exposure experiment using zebrafish, from 0 to 5 days post fertilization (dpf). The possible adverse effects of THI on the early-life stages of zebrafish were explored by investigating variations in their physiological parameters, behavioral traits, and neurotransmitter levels. The results showed THI exhibited significant developmental toxicity to aquatic organisms. Exposure to THI significantly induced serious malformation (at 50 µg/L), accelerated hatching, and elevated heart rate (at 5 and 50 µg/L). The behavioral traits of zebrafish larvae had an increased first and then decreased relationship with increasing concentration of THI, which induced hyperactivity at 0.5 µg/L but opposite at 50 µg/L. Furthermore, exposure to 50 µg/L THI significantly raised levels of 5-HT, 5-HIAA, DA, DOPAC and ACH in zebrafish larvae. In addition, several significant correlations between behavioral traits and the neurotransmitter contents were detected, which seemed to reveal an important mechanism of the neurobehavioral toxicity of THI to fish.

Breeding biology of Great White Pelican Pelecanus onocrotalus at Lake Tana, Ethiopia.

Great White Pelicans, once thriving at Lake Shala, have faced a decline in breeding pairs at Lake Abijata due to increased salinity and overfishing. A study at Lake Tana Biosphere, from December 2020 to December 2021, aimed to understand their breeding biology, which had not been previously documented. We conducted intensive searches for nests and monitored them during incubation and post-hatching to assess reproductive success. The study found pelicans breed year-round, with peaks from late December to March and June to July. The average clutch size was 2.14, with egg dimensions averaging 90.33 mm in length and 58.70 mm in breadth and a mean weight of 173.68 g. No significant differences were observed in these measurements, but a positive correlation was found between egg length, weight, and breadth and weight. However, no correlation existed between length and breadth. Out of 98 eggs, 84 hatched, resulting in 80 and 91.5 % hatchability rates across two breeding seasons, averaging 85.71 %. The hatching success rate did not differ significantly between seasons. Unfortunately, only 37 pelicans reached the pre-fledging stage, indicating a high mortality rate of 63 %. The study concluded that the breeding performance of Great White Pelicans at Lake Tana is poor, with human disturbance, overfishing, and predation on nestlings posing significant threats to their nesting success. This highlights the need for conservation efforts to address these challenges and protect the species.

Soluble Guanylate Cyclase α1 Gene Influences Egg-Laying Amount and Hatching Rate in Bombyx mori.

Soluble guanylate cyclase (sGC) serves as a receptor of nitric oxide (NO) and is the core metalloenzyme in the NO signal transduction pathway. sGC plays a key role in the NO-cGMP signal transduction pathway and participates in various physiological processes, including cell differentiation, neuron transmission, and internal environment homeostasis. sGC consists of two subunits, α and ß, each subunit containing multiple isoforms. In this study, we cloned and analyzed the sGC-α1 gene in the silkworm Bombyx mori (BmsGC-α1). The BmsGC-α1 gene was expressed highest at the pupal stages. The highest BmsGC-α1 mRNA expression was observed in the head of fifth instar larvae and in fat body during the wandering stage of B. mori. Furthermore, we observed that feeding fifth instar larvae with thyroid hormone and nitroglycerin induced the expression of the BmsGC-α1 gene. Injection of BmsGC-α1 siRNA into silkworms at the prepupal stage resulted in a significant decrease in BmsGC-α1 expression levels at 48 and 72 h postinjection. After silencing BmsGC-α1, both the egg-laying amount and hatching rate of silkworm eggs were significantly reduced compared to the control group. These results suggest that BmsGC-α1 plays an important role in regulating the reproductive system of silkworms. This finding enhances our understanding of the functional diversity of sGC in insects.

Sublethal effects of early-life exposure to common and emerging contaminants in birds.

The plight of wild birds is becoming critical due to exposure to environmental contaminants. Although laboratory studies have provided insights into the developmental effects of chemical exposures, less is known about the adverse effects of environmental chemicals in developing wild birds. Early life stages are critical windows during which long-term organization of physiological, behavioral, and neurological systems can occur. Thus, contaminant exposure at early life stages can directly influence survival and reproductive success, with consequences for population stability and resilience in wild species. This review synthesizes existing knowledge regarding both short- and long-term effects of early-life exposure to widespread contaminants in birds. We focus especially on wild birds and on contaminants of concern within the Gulf of Mexico as an example of a habitat under anthropogenic stress from exposure to a complex mixture of chemicals and changing land uses that exacerbate existing vulnerabilities of wildlife in this region. Chemical contaminants for discussion in this review are based on avian mortality records from the Wildlife Health Information Sharing Partnership (WHISPers) database and on additional review of the literature regarding avian contaminants of concern for the northern Gulf of Mexico, and include oil and associated polycyclic aromatic hydrocarbons, dioxin and dioxin-like compounds, flame retardants, pesticides, heavy metals, and plastics. We provide an overview of effects in bird species at both the pre-hatching and post-hatching early life stages, discuss differences in sensitivities by route of exposure, life stage, and life history, and provide recommendations for future research. We find that additional research is needed on altricial species, post-hatching early-life exposure, long-term effects, and on ecologically relevant contaminant concentrations and routes of exposure. Given the increasing frequency and intensity of anthropogenic stressors encountered by wild animals, understanding both lethal and sublethal impacts of contaminants on the health of individuals and populations will be critical to inform restoration, management, and mitigation efforts.

Comparative dataset on growth, development and reproductive performance of copepod (Cyclops sp.) fed with different microalgae diet.

The effects of growth and reproduction on the marine Cyclops sp. were investigated using three microalgae as diets. The development period of Cyclops sp. was evaluated at 106 cells/ml in 15ppt salinity to identify the stationary phase. The survival rate of marine Cyclops from nauplius to adult differed according to the microalgal diet. The results showed that the shortest time (14 days) and highest survival (17.6 ± 0.131 %) for Cyclops sp. was achieved with those fed with Nannochloropsis sp. Whereas, it took longest time (37 days) and lowest survival rate (6.40 ± 0.035 %) when fed Chlamydomonas sp. The developmental period from naupli (I - VI) (6.91 ± 0.453 days), copepodite (I - VI) (11.4 ± 0.311days) and naupli to adult (20 ± 1.08 days) appeared significantly longer when fed with Nannochloropsis sp. compared to other treatments. The daily mean naupli production of adult females over 7 days was significantly higher (p ˂ 0.05) in Nannochloropsis sp. compared with Chlamydomonas sp. and Gonyostomum sp. On the 25th day of Nannochloropsis sp. treatment, 99 % of the mature females died. Production (naupli, copepodite adult male and adult female) was significantly higher (p ˂ 0.05) in Nannochloropsis sp. than in other microalgal diets. On the fifteenth day, Nannochloropsis sp. showed a significantly higher (p ˂ 0.05) specific growth rate than other microalgal diets. Nannochloropsis sp. had the highest nauplius survival rate on the sixth day compared to other microalgal diets. With Nannochloropsis sp., the species has a higher hatching rate, and in Chlamydomonas sp. hatching occurs earlier. The average lifespan for Nannochloropsis sp. was 46 days, for Chlamydomonas sp. it was 37 days, and for Gonyostomum sp. it was 32 days.

Effect of Phage Spray on Hatchability and Chick Quality of Eggs Contaminated with Salmonella Typhimurium.

Salmonella Typhimurium (S. Typhimurium) contamination poses a significant challenge to breeder egg hatchability and chick health, necessitating the exploration of alternative disinfection methods. This study investigates the potential of phage vB_SPuM_SP02 (SP02) as a novel disinfectant for breeder eggs contaminated with S. Typhimurium SM022. Phage SP02 was isolated from poultry farm effluent and characterized for morphology, biological properties, and genome properties. Experimental groups of specific pathogen-free (SPF) eggs were treated with Salmonella and phage SP02, and efficacy was assessed through hatching rates, chick survival, weight, Salmonella load, immune organ indices, and intestinal flora. Phage treatment effectively eradicated Salmonella contamination on eggshells within 12 h, resulting in increased hatching and survival rates compared to controls. Furthermore, phage treatment mitigated weight loss and tissue Salmonella load in chicks without causing immune organ damage while reducing Salmonella spp. abundance in the intestinal tract. This study demonstrates the potential of phage SP02 as an eco-friendly and efficient disinfectant for S. Typhimurium-contaminated breeder eggs, offering promising prospects for practical application in poultry production.

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.

Embryo thermal manipulation modifies development and hepatic lipid metabolism in post-hatch layer-type chicks.

Incubation temperature is a crucial environmental factor affecting embryonic development and chick quality. Metabolism during the embryonic stage, particularly liver lipid metabolism, is essential for the growth and development of poultry. This study aimed to investigate the effects of embryo thermal manipulation with high (TMH, 39.5 °C, 65% RH, 8 h/d) and low (TML, 20 °C, 65% RH, 1 h/d) temperatures during 8th to 15th embryonic age on hatching performance and liver lipid metabolism in layer chicks. Additionally, the duration of TM effects was evaluated through a short-term feeding trial. The results indicated that TMH accelerated the hatching process without significantly affecting hatchability and growth performance. In contrast, TML delayed hatching time and significantly reduced hatchability and chick quality. After hatching, TML also increased residual yolk weight and reduced the relative liver weight in relation to body weight and yolk-free body mass. Moreover, lipid droplets in the liver were stained with Oil Red O, and the lipid content in the liver and serum was further detected. TMH had no significant impact on triglyceride (TG) and total-cholesterol (TCHO) content in the liver and serum but upregulated the expression of lipogenesis-related genes ACC, Fas, and Fatp1 compared to the TML group. Conversely, TML significantly reduced liver TG content, enhanced lipoprotein lipase (LPL) activity, and promoted the expression of lipid oxidation-related genes CPT-1, PGC-1α, and PPARα. At 7 d of age, liver LPL activity was significantly increased in the TMH group. However, there were no significant changes in the content of TG and TCHO in the liver and the expression of lipid metabolism-related genes in the TML group. Overall, these results indicate that embryonic TM alters hatching performance and liver lipid metabolism in layer chicks. TML reduces TG content by increasing liver lipid oxidation capacity. However, this effect is not long-lasting, as the influence of TM diminishes as the chicks develop.

Incubation temperature is a crucial environmental factor affecting embryonic development and chick quality. The liver is the primary tissue of lipid metabolism in poultry. During incubation, it is responsible for converting yolk fatty acids into forms usable by the embryo. However, it remains unclear whether changes in embryonic incubation temperature can affect liver lipid utilization. This study aimed to investigate the effects of embryo thermal manipulation with high temperature and low temperature on the hatching performance and liver lipid metabolism of layer chicks. The results showed that high incubation temperature had limited effects on hatchability and liver lipid metabolism, while low incubation temperatures not only delayed hatching time and significantly reduced hatchability, but also altered liver lipid metabolism and promoted the expression of genes related to lipid oxidation. However, these changes weakened or even disappeared as the chicks grew. This suggests that while embryo thermal manipulation affects the hatching performance and liver lipid metabolism of layer-type chicks, these effects are not persistent.