Developmental energetics in the oviparous corn snake, Pantherophis guttatus, confirms a conservative evolutionary pattern in snakes.

Eggs of oviparous reptiles are ideal models for studying evolutionary patterns of embryonic metabolism since they allow tracking of energy allocation during development. Analyzing oxygen consumption of whole eggs throughout development indicates three patterns among reptiles. Embryos initially grow and consume oxygen exponentially, but oxygen consumption slows, or drops before hatching in some species. Turtles, crocodilians, and most lizards follow curves with initial exponential increases followed by declines, whereas embryonic snakes that have been studied exhibit a consistently exponential pattern. This study measured oxygen consumption of corn snake, Pantherophis guttatus, embryos to determine if this species also exhibits an exponential increase in oxygen consumption. Individual eggs, sampled weekly from oviposition to hatching, were placed in respirometry chambers for 24-h during which oxygen consumption was recorded. Embryos were staged and carcasses and yolk were weighed separately. Results indicate steady inclines in oxygen consumption during early stages of development, with a rapid increase prior to hatching. The findings support the hypothesis that embryonic oxygen consumption of snakes differs from most other non-avian reptiles. Total energy required for development was determined based on calorimetry of initial yolk compared to hatchlings and residual yolk and by integration of the area under the curve plotting oxygen consumption versus age of embryos. The cost of development estimates based on these two methods were 6.4 and 10.0 kJ, respectively. Our results emphasize the unique physiological aspects of snake embryogenesis and illustrate how the study of physiological characteristics can contribute to the broader understanding of reptilian evolution.

Comparison of Reproductive Strategies between Two Sympatric Copsychus Passerines.

Reproduction plays a crucial role in determining the development, fate, and dynamics of bird populations. However, reproductive strategies vary among species and populations. In this study, we investigated the reproductive strategies of the Oriental Magpie Robin (Copsychus saularis) and White-rumped Shama (C. malabarica), which are closely related passerines that reproduce in sympatric areas. We found that although these two species were both cavity nesting, their nest-site selection differed; the Shama preferred nesting close to trees and forests, whereas the Magpie Robin nested close to human residential areas. Furthermore, their egg incubation patterns differed; the Shama increased daily incubation frequency with incubation time, but the Magpie Robin maintained its daily incubation time regardless of changes in incubation frequency. However, the nestling heating patterns of these two species were similar, indicating a critical demand for regulating hatchling body temperature during this crucial stage. The feeding frequencies of male parents were strongly correlated with those of females in both species, suggesting equal contribution and good synchronization between the sexes. Nestling feeding frequency was also correlated with nest cleaning frequency, implying coordination between feeding and defecation by parents and offspring, respectively. This research explored the divergence and convergence of reproductive strategies between these two sympatric species, providing valuable insights into the niche differentiation theory.

Dietary non-phytate phosphorus requirements for optimal productive and reproductive performance, and egg and tibial quality in egg-type duck breeders.

Optimal dietary non-phytate phosphorus (NPP) is essential in poultry to maximise productive and reproductive performance, along with indices of egg and bone quality. This study aimed to establish the NPP requirements of egg-type duck breeders aged from 54 to 80 weeks on the following traits: egg production, egg incubation, egg quality, tibial characteristics, reproductive organ, plasma indices, and the expression of genes related to phosphorus absorption. Longyan duck breeders aged 54 weeks (n = 300) were randomly allotted to five treatments, each containing six replicates of 10 individually caged birds. Birds were fed corn-soybean meal-based diets containing 0.18, 0.25, 0.32, 0.38, and 0.45% NPP/kg for 27 weeks. The tested dietary NPP levels did not affect egg production or egg quality indices. The hatchling weight of ducklings increased (quadratic, P < 0.01) as dietary NPP level increased, and the highest value occurred with 0.25% NPP. The number of large yellow follicles (LYF), and the relative weights of LYF and ovary showed linear and quadratic responses to dietary NPP levels; the lowest number and relative weight of LYF occurred with 0.38% NPP, and the lowest ovarian weight was obtained with 0.25% NPP. There were no differences in tibial length, breaking strength, and mineral density in response to dietary NPP levels. In contrast, tibial content of Ca increased (linear, P < 0.01) with dietary NPP levels increasing from 0.18 to 0.45%, and the tibial content of P increased at 0.32% NPP and the higher dietary NPP levels. Plasma concentration of P showed a quadratic (P < 0.05) response to the dietary NPP levels, where the highest value was seen at 0.38% NPP. In conclusion, dietary NPP levels from 0.18 to 0.45% had no effects on egg production, and egg and tibial quality of duck breeders. The duck breeders fed a diet with 0.25% NPP showed the highest hatchling weight of their offspring, while those fed 0.38% NPP had the lowest number and relative weight of LYF. These results indicated that the diet with 0.25% NPP can be used in egg-type duck breeders to improve the hatchling weight of their offspring, without adverse effects on their productivity. The regression model indicated that the maximal hatchling weight of ducklings was obtained from duck breeders fed the diet with 0.30% NPP.

Adapting conservation breeding techniques using a data-driven approach to restore the 'Alala (Hawaiian crow, Corvus hawaiiensis).

For some critically endangered species, conservation breeding is a vital steppingstone toward re-establishing wild populations. The 'Alala (Hawaiian crow, Corvus hawaiiensis), currently extinct in the wild, exists today only in a conservation breeding program, which, for many years, utilized successful hands-on husbandry approaches such as separating and resocializing pairs, providing partially manmade nests, artificially incubating eggs, and puppet rearing nestlings. Yet, a top priority of any conservation breeding program is to retain natural behaviors essential to postrelease survival and reproduction, to achieve successful reintroduction and restoration to the wild. We describe how we are adapting 'Alala husbandry techniques to strengthen pair bonds through full-time socialization, enable pairs to build robust nests, encourage females to incubate eggs to hatch, and provide pairs and their offspring with vital parental rearing experiences. We discuss the use of standardized, data-driven methods to objectively track our progress towards successful parental breeding and to select release candidates based on their likelihood to survive and breed in the wild. The information shared in this report can be applied to other conservation breeding programs, particularly those implementing or transitioning to husbandry techniques geared towards preparing species to thrive in the wild.

Nest-Site Features and Breeding Ecology of Chestnut-Vented Nuthatch Sitta nagaensis in Southwestern China.

The breeding ecology of birds is the cornerstone of bird life-history theory, and breeding success directly affects the survival and development of populations. We studied the breeding ecology of a secondary cavity-nesting bird, the chestnut-vented nuthatch Sitta nagaensis, in southwestern China from March to June in 2020, 2021, and 2022. In total, 16 nests in nest boxes and 19 nests in natural cavities were studied. The nesting habitat was mainly Pinus yunnanensis forest (68.4%), and the nest trees were mainly P. yunnanensis and pear Pyrus spp. Cavities made by woodpeckers and knot holes were used as nest sites, and the nuthatches plastered the hole entrance with mud. The nesting material was mainly pine bark. The clutch size was 3.47 ± 0.56 (range 2-4, n = 30), with an incubation period of 16.06 ± 0.91 days (range 15-19 days, n = 18). The nestling period was 20.88 ± 1.90 days (range 18-23 days, n = 23), and both parents fed the nestlings.

Slightly acidic electrolyzed water as an alternative disinfection technique for hatching eggs.

Conventional chemical disinfectants used for egg disinfection could result in toxic residue and endanger hatchability, chick quality, and pullet growth performance. Slightly acidic electrolyzed water (SAEW) is known as a novel disinfectant for egg sterilization due to its high efficiency and no residue. In this study, a comprehensive assessment of slightly acidic electrolyzed water and benzalkonium bromide solution (BBS) used in the disinfection channel was conducted to assess the microbial count, eggshell quality, and hatchability concomitantly. The results show that the sterilization efficiency of SAEW increased with an increase in available chlorine concentration (ACC), spraying volume, and sterilization duration. SAEW with an ACC of 150 mg/L and 10,000 mg/L benzalkonium bromide solution had the same sterilization rates of approximately 86.2% at a spraying volume of 0.5 mL/egg and sterilization duration of 180 s. Neither had significant effect on eggshell strength or thickness. The eggshell cuticle quality in the benzalkonium bromide group was significantly higher than the control group (no disinfection) and the 150 mg/L SAEW group. The embryo weight, relative embryo weight, hatchability, and embryonic mortality in the SAEW group had no significant differences of those in the benzalkonium bromide group. SAEW should be more popular because of its simple preparation, low cost, and no residue. Our results indicate SAEW is an alternative disinfectant for the sterilization of hatching eggs instead of conventional chemical disinfectants, such as benzalkonium bromide, and give a recommendation is using SAEW as a disinfectant with 150 mg/L ACC, 0.5 mL/egg spray volume, and disinfection for 180 s in the novel disinfection channel.

Natural nest substrates influence squamate embryo physiology but have little effect on hatchling phenotypes.

Vertebrate embryos require access to water; however, many species nest in terrestrial habitats that vary considerably in moisture content. Oviparous, non-avian reptiles have served as models to understand how environmental factors, like moisture availability, influence development because eggs are often exposed to prevailing environments in the absence of parental care. Though much research demonstrates the importance of water absorption by eggs, many ecological factors that influence moisture availability in natural nests have received little attention. For example, the type of substrate in which nests are constructed is understudied. We experimentally incubated eggs of the brown anole lizard (Anolis sagrei) in 2 naturally occurring nest substrates that were treated with varying amounts of water to determine how natural substrates influence development at different moisture concentrations. One substrate consisted of sand and crushed seashells and the other was mostly organic material (i.e. decayed plant material). Both are common nesting substrates at our field site. When controlling for water uptake by eggs, we found that egg survival and hatchling phenotypes were similar between substrates; however, embryos developed more quickly in the sand/shell substrate than the organic substrate, indicating substrate-specific effects on embryo physiology. These results demonstrate that different natural substrates can result in similar developmental outcomes if the water available to eggs is comparable; however, some aspects of development, like developmental rate, are affected by the type of substrate, independent of water availability. Further study is required to determine how natural substrates influence embryo physiology independent of water content.

Pre-hatching and post-hatching environmental factors related to epigenetic mechanisms in poultry.

Epigenetic modifications are phenotypic changes unrelated to the modification of the DNA sequence. These modifications are essential for regulating cellular differentiation and organism development. In this case, epigenetics controls how the animal's genetic potential is used. The main epigenetic mechanisms are microRNA activity, DNA methylation, and histone modification. The literature has repeatedly shown that environmental modulation has a significant influence on the regulation of epigenetic mechanisms in poultry. The aim of this review is to give an overview of the current state of the knowledge in poultry epigenetics in terms of issues relevant to overall poultry production and the improvement of the health status in chickens and other poultry species. One of the main differences between birds and mammals is the stage of embryonic development. The bird's embryo develops outside its mother, so an optimal environment of egg incubation before hatching is crucial for development. It is also the moment when many factors influence the activation of epigenetic mechanisms, i.e., incubation temperature, humidity, light, as well as in ovo treatments. Epigenome of the adult birds might be modulated by nutrition, supplementation, and treatment, as well as modification of the intestinal microbiota. In addition, the activation of epigenetic mechanisms is influenced by pathogens (i.e., pathogenic bacteria, toxins, viruses, and fungi) as well as the maintenance conditions. Farm animal epigenetics is still a big challenge for scientists. This is a research area with many open questions. Modern methods of epigenetic analysis can serve both in the analysis of biological mechanisms and in the research and applied to production system, poultry health, and welfare.

Epigenetic modifications are phenotypic changes unrelated to the modification of the DNA sequence. In this case, epigenetics controls how the animal's genetic potential is used. The literature has shown that environmental modulation has a significant influence on the regulation of epigenetic mechanisms in poultry. The aim of this review is to give an overview of the current state of the knowledge in poultry epigenetics in terms of issues relevant to overall poultry production and the improvement of the health status in poultry. The bird's embryo develops outside its mother, so an optimal environment of egg incubation before hatching is crucial for development. It is also the moment when many factors influence the activation of epigenetic mechanisms, i.e., incubation temperature, humidity, light, as well as in ovo treatments. Epigenome of the adult birds might be modulated by nutrition, supplementation, and treatment, as well as modification of the intestinal microbiota. The activation of epigenetic mechanisms is influenced by pathogens as well as the maintenance conditions. Farm animal epigenetics is still a big challenge for scientists. Modern methods of epigenetic analysis can serve both in the analysis of biological mechanisms and in the research and applied to production system, poultry health, and welfare.

Eggs Immersion with Vitamin C on Hatching Rate, Growth and Mortality of Giant Gourami Larvae.

<b>Background and Objective:</b> The giant gourami (<i>Osphronemus goramy</i>; Lacepede, 1801) is one of Indonesia's main freshwater fish of economic benefit for food security. This study evaluated the effects of vitamin C dosages used for immersion embryonic and larval of giant gourami. <b>Materials and Methods:</b> The vitamin C using Ascorbic acid standard (FLUKA, Sigma-Aldrich), each weighed 50, 100, 150 and 200 mg and dissolved in 1 L of fresh borehole water is referred to as P₂, P₃, P₄ and P₅. At the same time, 1 L of fresh borehole water not added with vitamin C is called P₁ (Placebo). Each treatment was formulated with 5 L and poured into an incubator tank with a capacity of 10 L Then, as many as 150 eggs are incubating per experiment in each incubator tank. These larvae of each experiment were rearing for 20 days using live feed (tubifex) 40% per feed. Each treatment was three replicates. <b>Results:</b> In this study, larval hatching rates varied from 78.59-98.22%, with the survival of endogenous feeding periods ranging between 93.08 and 99.10%. The specific growth rate increased from 11.14 and 13.38% per day. The Coefficient of thermal growth increased from 1.49-1.70. Larval mortality after exogenous feeding for 20 days of the experiment decreased from 21.11-5.56%. The Coefficient of variation in weight was between 3.19 and 14.04%. <b>Conclusion:</b> Giant gourami eggs and larvae hatched and survived and grew well in immersion with a dose of vitamin C up to 200 mg L¹.

Improvement of the Mass-Rearing Protocols for the South American Fruit Fly for Application of the Sterile Insect Technique.

The existing rearing protocols for Anastrepha fraterculus must be reviewed to make economically viable the production of sterile flies for their area-wide application. Additionally, evidence of sexual incompatibility between a long-term mass-reared Brazilian strain and wild populations has been found. To address these issues, this study aimed to refine rearing protocols and to assess the suitability of an A. fraterculus strain for the mass production of sterile flies. A series of bioassays were carried out to evaluate incubation times for eggs in a bubbling bath and to assess the temporal variation of egg production from ovipositing cages at different adult densities. A novel larval diet containing carrageenan was also evaluated. Egg incubation times higher than 48 h in water at 25 °C showed reduced larval and pupal yields. Based on egg production and hatchability, the density of 0.3 flies/cm2 can be recommended for adult cages. The diet with carrageenan was suitable for mass production at egg-seeding densities between 1.0 and 1.5 mL of eggs/kg of diet, providing higher insect yields than a corn-based diet from Embrapa. Even after two years of being reared under the new rearing protocols, no sexual isolation was found between the bisexual strain and wild flies.

Influence of incubation temperature on embryo development, hatchling morphology and early growth rate in red-footed tortoise (Chelonoidis carbonaria).

Reptile embryos respond to temperature changes with metabolic and physiological adjustments that influence hatchling success, phenotype, behaviour, and growth rate. Climate change and global warming can affect the reptile population by altering the frequencies of hatchling survival and phenotypes. Therefore, previous studies proposed artificial incubation as a potential strategy for mitigating these effects. Red-footed tortoise (Chelonoidis carbonaria) eggs were collected and incubated at constant temperatures of 27.5 °C and 29.5 °C to investigate the physiological effects of temperature on embryo development, hatchling morphology, and early post-hatch growth rate. The direct effect of temperature on the incubation period, egg mass loss, hatching success, hatchling size, and mass was evaluated at hatching and three months of age. Hatchlings from 29.5 °C presented a shorter incubation period (141 days) than those from 27.5 °C (201 days; p < 0.05). Egg mass loss, hatchling mass, and size at hatching were not different between the incubation temperatures (p > 0.05). However, the hatching success (survival rate) was lower (64.5% versus 100%) in eggs incubated at 29.5 °C, but the hatchling mass and straight plastron width were higher at three months of age than those from eggs incubated at 27.5 °C (p < 0.05). These results indicate that incubation temperature influences hatching success and hatchling size and mass in the first months by influencing the early growth rate.

Modulations of lipid metabolism and development of the Atlantic salmon (Salmo salar) fry in response to egg-to-fry rearing conditions.

In stocking program, the use of artificial incubation conditions in hatcheries from the fertilisation of eggs to the release of unfed fry could reduce their ability to adapt to the natural environment. This study evaluates the effects of three factors on the fitness and physiology of salmon fry at their emergence, the origin of water (river vs drilling), the type of support in the incubator (support matrix vs plastic sheets) and the type of incubators (Californian vs vertical trays), and compares them to a semi-natural incubation method in river. Key biological functions including nutritional and immune status were compared among experimental conditions using biometric parameters, lipid composition and gene expression analyses. Our findings demonstrated that fry incubated in vertical trays supplied with river water had no significant difference in growth and lipid composition compared to those in semi-natural incubators. Besides, fry incubated on a substrate matrix in Californian trays exhibited phenotypic characteristics closest to those incubated in river. This support matrix improved fish growth, lipid consumption and distribution compared to fry on plastic sheets. Moreover, the large amounts of several PUFAs in these fry could allow a better membrane fluidity ensuring a better adaptation to temperature variation under cold conditions. In addition, drilling water improved the survival rate compared to river water due to lower numbers of fine particles, known to be responsible for the clogging of eggs. To conclude, using a substrate combined with drilling water in artificial incubators could increase fry fitness and its adaption to wild life.

Breeding of a Wild Population of South Pacific Bonito Sarda chiliensis chiliensis (Cuvier 1832) Broodstock under Laboratory Conditions in Pisagua, Northern Chile.

The wild population of South Pacific bonito Sarda chiliensis chiliensis, which has a wide distribution in northern Chile, is considered of importance in Chilean aquaculture. The biological feasibility of cultivation of any marine species begins with the establishment of an initial broodstock population to obtain eggs, larvae, and juveniles. In this work, 22 South Pacific bonito fishing campaigns were carried out in Pisagua, Chile, between spring in November 2011 and the summer in January 2012. At least 74 specimens were obtained of which 24 survived the capture and transport processes. Fish were stocked in a recirculating land-based aquaculture system, and at 14 months under captivity, fish began spawning. Eggs were collected, to describe some stages of development, and were placed in incubators at 20 °C and on the third-day eggs hatched. Larvae reached a total length between 1.435 and 1.7 mm, which were accurately characterized during their first morphological changes. This is the first work that describes the capture, transport, and acclimatization in captivity of a breeding population of wild Pacific bonito in Chile.

Ecologically relevant thermal fluctuations enhance offspring fitness: biological and methodological implications for studies of thermal developmental plasticity.

Natural thermal environments are notably complex and challenging to mimic in controlled studies. Consequently, our understanding of the ecological relevance and underlying mechanisms of organismal responses to thermal environments is often limited. For example, studies of thermal developmental plasticity have provided key insights into the ecological consequences of temperature variation, but most laboratory studies use treatments that do not reflect natural thermal regimes. While controlling other important factors, we compared the effects of naturally fluctuating temperatures with those of commonly used laboratory regimes on development of lizard embryos and offspring phenotypes and survival. We incubated eggs in four treatments: three that followed procedures commonly used in the literature, and one that precisely mimicked naturally fluctuating nest temperatures. To explore context-dependent effects, we replicated these treatments across two seasonal regimes: relatively cool temperatures from nests constructed early in the season and warm temperatures from late-season nests. We show that natural thermal fluctuations have a relatively small effect on developmental variables but enhance hatchling performance and survival at cooler temperatures. Thus, natural thermal fluctuations are important for successful development and simpler approximations (e.g. repeated sine waves, constant temperatures) may poorly reflect natural systems under some conditions. Thus, the benefits of precisely replicating real-world temperatures in controlled studies may outweigh logistical costs. Although patterns might vary according to study system and research goals, our methodological approach demonstrates the importance of incorporating natural variation into controlled studies and provides biologists interested in thermal ecology with a framework for validating the effectiveness of commonly used methods.

Eggs of tegu lizard, Salvator merianae (Duméril & Bilbron, 1839) (Squamata; Teiidae) damaged by fungal infections / Ovos de lagarto tegu, Salvator merianae (Duméril e Bilbron, 1839) (Squamata; Teiidae) danificados por infecções fúngicas

Abstract The tegu (Salvator merianae) is the largest lizard found in Brazil and has a wide distribution, occurring in several biomes. The presence of fungi on reptilian eggs initially occurs on infertile eggs, which leads to a subsequent infection in fertile eggs, causing damage and death of embryos. The objective of this study was to identify the fungi that caused lesions in the eggs of tegu in captivity. Swabs were collected on infected and healthy eggshells, in an embryo that died and the substrate of the incubation box. Samples were submitted to saboraund dextrose agar. A total of 93.3% of positive samples were obtained for the fungi Fusarium (11/14), Trichoderma (1/15), Penicilium (1/15), Mucor (1/15), and yeasts of the genus Trichosporon. Therefore, Fusarium was the main agent that caused the lesion and death of embryos in the eggs of the tegu lizard. Sanitary control methods may be taken to avoid fungal infections in the eggs.

Resumo O teiú (Salvator merianae) é o maior lagarto encontrado no Brasil e possui ampla distribuição, sendo encontrado em vários biomas. A presença de fungos em ovos de répteis ocorre inicialmente em ovos inférteis, o que leva à uma infecção posterior em ovos férteis, gerando danos e morte dos embriões. O objetivo deste estudo foi o de identificar os fungos geradores de lesões em ovos de teiú em cativeiro. Foram coletados suabes na casca de ovos infectados e sadios, além de um embrião que veio a óbito, e do substrato presente na caixa de incubação. As amostras foram submetidas ao cultivo em ágar Saboraund dextrose. Um total de 93,3% de amostras foram positivas para os fungos Fusarium (11/15), Trichoderma (1/15), Penicillium (1/15), Mucor (1/15) e leveduras do gênero Trichosporon (3/15). Logo, Fusarium foi o principal agente causador das lesões e morte de embriões nos ovos do lagarto teiú. Métodos de controle sanitário podem ser adotados para evitar infecção fúngicas nos ovos.

How to walk carrying a huge egg? Trade-offs between locomotion and reproduction explain the special pelvis and leg anatomy in kiwi (Aves; Apteryx spp.).

Kiwi (Aves; genus Apteryx) are famous for laying an enormous egg in comparison with their relatively small body size. Considering the peculiar gait of this flightless bird, we suspected the existence of morpho-functional trade-offs between reproduction and locomotion. To understand how structural constraints, imposed by a large egg size, might influence the terrestrial locomotion of Apteryx, we analysed the anatomy of the limb osteomuscular system in two species of kiwi (Apteryx mantelli and Apteryx owenii). We performed detailed dissections and brought to light specific anatomical features of kiwi, in comparison with other ratites and neognathous birds. Our osteological study revealed a strongly curved pelvis, a rigid tail, and enlarged ribs. Our myology study showed an unusual location of the caudofemoralis muscle origin and insertion. The insertion of the pars pelvica along the entire caudal face of the femur, contrasts with the proximal insertion usually seen in other birds. Additionally, the pars caudalis originates along the entire tail, whereas it only inserts on the uropygium in the other birds. To interpret these specificities from a functional point of view, we built three-dimensional osteomuscular models based on computed tomography scans, radiographies and our dissections. We chose three postures associated with reproductive constraints: the standing position of a gravid compared with a non-gravid bird, as well as the brooding position. The 3D model of the brooding position suggested that the enlarged ribs could support the bodyweight when leaning on the huge egg in both males and females. Moreover, we found that in gravid females, the unusual shape of the pelvis and tail allowed the huge egg to sit ventrally below the pelvis, whereas it is held closer to the rachis in other birds. The specific conformation of the limb and the insertions of the two parses of the caudofemoralis help to maintain the tail flexed, and to keep the legs adducted when carrying the egg. The caudal location of the hip and its flexed position explains the long stance phase during the strange gait of kiwi, revealing the functional trade-off between reproduction and locomotion in this emblematic New Zealand bird.

Avian yolk androgens are metabolized rather than taken up by the embryo during the first days of incubation.

Several studies show effects of yolk androgens in avian eggs on the phenotype of the offspring. Yolk hormone concentrations decline strongly within the first few days of incubation. Although early embryonic uptake of yolk androgens is suggested by the presence of radioactivity in the embryo when eggs are injected with radiolabelled androgens, these studies do not verify the chemical identity of radioactive compound(s), although it is known that these androgens can be metabolized substantially. By using stable isotope-labelled testosterone and androstenedione in combination with mass spectrometry, enabling verification of the exact molecular identity of labelled compounds in the embryo, we found that after 5 days of incubation the androgens were not taken up by the embryo. However, their concentrations in the entire yolk albumen homogenates declined strongly, even when corrected for dilution by albumen and water. Our results indicate metabolism of maternal androgens, very likely to 5ß-androstane-3α,17ß-diol, etiocholanolone and their conjugated forms. The results imply that the effects of increased exposure of the embryo to maternal androgens take place either before this early conversion or are mediated by these metabolites with an as yet unknown function, opening new avenues for understanding hormone-mediated maternal effects in vertebrates.

Prebiotics and synbiotics - in ovo delivery for improved lifespan condition in chicken.

Commercially produced chickens have become key food-producing animals in the global food system. The scale of production in industrial settings has changed management systems to a point now very far from traditional methods. During the perinatal period, newly hatched chicks undergo processing, vaccination and transportation, which introduces a gap in access to feed and water. This gap, referred to as the hatching window, dampens the potential for microflora inoculation and as such, prevents proper microbiome, gastrointestinal system and innate immunity development. As a consequence, the industrial production of chickens with a poor microbial profile leads to enteric microbial infestation and infectious disease outbreaks, which became even more prevalent after the withdrawal of antibiotic growth promoters on many world markets (e.g., the EU).This review presents the rationale, methodology and life-long effects of in ovo stimulation of chicken microflora. In ovo stimulation provides efficient embryonic microbiome colonization with commensal microflora during the perinatal period. A carefully selected bioactive formulation (prebiotics, probiotics alone or combined into synbiotics) is delivered into the air cell of the egg on day 12 of egg incubation. The prebiotic penetrates the outer and inner egg membranes and stimulates development on the innate microflora in the embryonic guts. Probiotics are available after the mechanical breakage of the shell membranes by the chick's beak at the beginning of hatching (day 19). The intestinal microflora after in ovo stimulation is potent enough for competitive exclusion and programs the lifespan condition. We present the effects of different combinations of prebiotic and probiotic delivered in ovo on day 12 of egg incubation on microflora, growth traits, feed efficiency, intestinal morphology, meat microstructure and quality, immune system development, physiological characteristics and the transcriptome of the broiler chickens.We discuss the differences between in ovo stimulation (day 12 of egg incubation) and in ovo feeding (days 17-18 of egg incubation) and speculate about possible future developments in this field. In summary, decades of research on in ovo stimulation and the lifelong effects support this method as efficient programming of lifespan conditions in commercially raised chickens.

Investigating parental care behaviour in same-sex pairing of zoo greater flamingo (Phoenicopterus roseus).

Same-sex pair bonds have been documented in several animal species and they are widespread in birds. However, little is known about the evolutionary origin and the adaptive value of such behaviour. The aim of this study was to investigate the parental behaviour of four zoo female greater flamingos involved in two breeding pairs, housed in a flock at Parco Natura Viva, Italy. Further, the behaviour of the study females was compared with that of male and female flamingos in heterosexual pairs described in a previous published work on this same flock. For each pair, the behaviour of both birds during the incubation period was recorded and twenty 10-minute sessions were run within the incubation period. A continuous focal animal sampling method was used to collect data on location (on the nest or not on the nest) and the parental care behaviour (e.g.: agonistic behaviours toward disturbing conspecifics, egg-care, nest-building, self-comfort behaviour, sleeping) of the two pairs. Data of the current study females were compared with those of females and males involved in heterosexual pairs of this same flock. Results showed that within each pair the egg-layer female stayed away from the nest more than the other female. In addition, the female that did not lay an egg was more involved in agonistic behaviour compared to other females, particularly when in specific locations. In heterosexual pairs, male flamingos were more involved in the incubation and in nest protection. Moreover, no significant differences in the time spent on the nest and away from the nest between the heterosexual male and the non-layer females of same-sex pairs were found. The same findings were reported when comparing heterosexual females and the egg-layer females of the same-sex pairs. Therefore, our findings suggest that in greater flamingos the behaviour of the female-female pairs seems to be equivalent to that of male-female bonds. Such research provides more insight into flamingo social behaviour, and their reproductive cycle, and provides information on why pair bonds may form and how these affect the wider breeding behaviour of the flock.

Quantifying the effects of embryonic phenotypic plasticity on adult phenotypes in reptiles: A review of current knowledge and major gaps.

Studies of reptiles have contributed greatly to understanding the impacts of developmental environments on offspring phenotypes. A major challenge for these studies, however, is quantifying the effects of embryonic environments on adult phenotypes and reproductive success. Such measurements may be necessary to gain full insight into the evolution of plasticity, as well as the long-term consequences of plasticity under environmental change. Unfortunately, most studies of reptile developmental plasticity only measure phenotypic traits of offspring at hatching, and rarely evaluate effects on subsequent adult phenotypes. This lack of information highlights a major gap in this active field. In this review, we first discuss conceptual issues regarding the ecology and evolution of plasticity to provide justification for long-term studies necessary to measure adult phenotypes. Second, we review case studies of reptiles that assessed the effects of developmental environments on adult phenotypes and/or reproduction, and we highlight the valuable insights that they provide. Importantly, we illustrate that terminating studies during early-life stages can lead to incomplete or even misleading interpretations. Third, we discuss the pros and cons of different experimental approaches for quantifying long-term effects of developmental environments. Overall, devoted long-term studies on taxa with diverse ecologies and life histories will provide major advances in the field of developmental plasticity.