Male-male sexual behavior in Japanese quail: being "on top" reduces mating and fertilization with females

A critical review on the welfare of Japanese quail in cage-free housing: Current knowledge and future perspectives

The Japanese quail (Coturnix japonica) is an increasingly popular species in poultry production. Concern about poultry welfare, including quail, has resulted in a stronger focus for farms to transition to cage-free housing as highlighted by the 2020 European Citizens' Initiative 'End the Cage Age'. Knowledge about how to design cage-free housing to accommodate Japanese quail's behavioral and physiological needs is scarce, and there are currently no standardized regulations regarding this type of housing for quail in the EU. Based on available literature, we review current information on the specific needs and requirements of quail to facilitate the transition to cage-free systems. Overall, the literature shows that Japanese quail spend most of their time on the ground, often pecking, scratching, or hiding under cover, that they will lay eggs in nests if these are provided and appropriately designed, and that they dustbathe if given substrate to do so. However, information about optimal group size, stocking density, nest design, and appropriate litter substrates have not been sufficiently well researched in non-cage systems, and neither has the design of cage-free housing when large groups of quail are housed together. Additionally, guidelines regarding successful management of the reportedly high level of agonistic behavior performed by male quail housed in groups is missing, as well as instructions on the ideal sex ratio in large breeding flocks. In addition to controlled experimental studies to fill specific knowledge gaps in these areas, we suggest precision livestock farming technologies such as real-time image analysis and modelling using artificial intelligence to gather this information on farms and/or in research studies. We also suggest using genomic selection to tackle the high levels of agonistic behavior reported in male Japanese quail by identifying the genetic architecture underlying this trait to facilitate faster selection against it. While phasing out caged housing for Japanese quail has been suggested to ensure better animal welfare, this review highlights that more information and research are needed to guarantee that this transition doesn't introduce new welfare and general managing problems in quail. We suggest that knowledge and experience about this transition from other poultry species, especially laying hens, can be used to facilitate the transition.

Microplastics and Their Impact on Reproduction-Can we Learn From the C. elegans Model?

Biologically active environmental pollutants have significant impact on ecosystems, wildlife, and human health. Microplastic (MP) and nanoplastic (NP) particles are pollutants that are present in the terrestrial and aquatic ecosystems at virtually every level of the food chain. Moreover, recently, airborne microplastic particles have been shown to reach and potentially damage respiratory systems. Microplastics and nanoplastics have been shown to cause increased oxidative stress, inflammation, altered metabolism leading to cellular damage, which ultimately affects tissue and organismal homeostasis in numerous animal species and human cells. However, the full impact of these plastic particles on living organisms is not completely understood. The ability of MPs/NPs to carry contaminants, toxic chemicals, pesticides, and bioactive compounds, such as endocrine disrupting chemicals, present an additional risk to animal and human health. This review will discusses the current knowledge on pathways by which microplastic and nanoplastic particles impact reproduction and reproductive behaviors from the level of the whole organism down to plastics-induced cellular defects, while also identifying gaps in current knowledge regarding mechanisms of action. Furthermore, we suggest that the nematode Caenorhabditis elegans provides an advantageous high-throughput model system for determining the effect of plastic particles on animal reproduction, using reproductive behavioral end points and cellular readouts.

An updated review on behavior of domestic quail with reference to the negative effect of heat stress

Japanese quail originated from the wildlife environment and was first domesticated in Japan in 1595. Japanese quail has widely distributed in various parts of the world. This bird is characterized by its rapid growth rate, high rate of egg production, much lower space requirements, small size, good reproductive potential, short life cycle, resistance to diseases, early sexual maturity (from 39 to 50 days), better laying ability and shorter time of hatching compared with the different species of poultry. All these characteristics rendered it an excellent laboratory animal and a good economical animal protein source (for both egg and meat). Thermal stress was found to be the major limiting variable in poultry production, directly influencing bird welfare conditions. Previous research showed that heat stress in the production environment, induced by high ambient temperatures, may have a direct detrimental effect on welfare, meat quality, carcass characteristics, productivity, egg mass and egg quality. Furthermore, heat stress directly decreases quails' reproductive performance. As tiny, ground-dwelling birds, quail may appear unable to handle extreme temperatures, yet they have methods of fighting the heat. This review will help in developing and strengthening the core of the quail-based poultry sector. In addition, it provides aggregate information on the characteristics of the quail bird as a production unit in poultry farms as well as being an animal model for laboratory experiments. Also, this review provided deep insight into the domestication process and the impact of heat stress on production characteristics, which altered the domestic or Japanese quail substantially.

Effect of chronic intracerebroventricular administration of an aromatase inhibitor on the expression of socio-sexual behaviors in male Japanese quail

Aromatase converts androgens into estrogens in the brain of vertebrates including humans. This enzyme is also expressed in other tissues where its action may result in negative effects on human health (e.g., promotion of tumor growth). To prevent these effects, aromatase inhibitors were developed and are currently used to block human estrogen-dependent tumors. In vertebrates including quail, aromatase is expressed in a highly conserved set of interconnected brain nuclei known as the social behavior network. This network is directly implicated in the expression of a large range of social behaviors. The primary goal of this study was to characterize in Japanese quail the potential impact of brain aromatase on sexual behavior, aggressiveness and social motivation (i.e., tendency to approach and stay close to conspecifics). An additional goal was to test the feasibility and effectiveness of long-term delivery of an aromatase inhibitor directly into the third ventricle via Alzet™ osmotic minipumps using male sexual behavior as the aromatase dependent measure. We demonstrate that this mode of administration results in the strongest inhibition of both copulatory behavior and sexual motivation ever observed in this species, while other social behaviors were variably affected. Sexual motivation and the tendency to approach a group of conspecifics including females clearly seem to depend on brain aromatase, but the effects of central estrogen production on aggressive behavior and on the motivation to approach males remain less clear.

Normative ocular data for juvenile and adult Japanese quail (Coturnix japonica)

OBJECTIVE

To obtain normative ocular data for Japanese quail as they mature from juveniles to adults.

ANIMALS STUDIED

Twenty-six captive Japanese quail comprising thirteen males and thirteen females, free of ocular disease, were included in the study.

PROCEDURES

Ophthalmic reference values were measured in both eyes at 1 and 5 months of age. A complete ophthalmic examination was performed, including neuro-ophthalmic reflexes, slit lamp biomicroscopy, phenol red thread test (PRTT), rebound tonometry, fluorescein staining, horizontal corneal diameter measurement, indirect ophthalmoscopy, and ocular ultrasound biometry. Ultrasound biomicroscopy measurements of axial globe length, lens thickness, vitreal chamber length, and pecten length were recorded. The depth of the anterior chamber was calculated by subtracting the lens thickness and vitreous length from the axial globe length. Measures of association and descriptive statistics were analyzed using STATA-14 and STATA-15.

RESULTS

Juvenile and adult females were heavier than age-matched males. Weight, intraocular pressure, horizontal corneal diameter, axial globe length, and lens thickness measurements increased with age. No statistically significant differences were found in the remainder of measurements among individuals in different sex or age-groups.

CONCLUSIONS

This work provides reference values and clinical findings that can be used in future research on quail and ocular disease.

Sexual and pairing partner preference in birds and other animals

Research on hormonal involvement in animals' preferences for mating or pairing with same- or other-sex partners has been among the topics featured in Hormones and Behavior over the years. In several species of non-pair-forming mammals, there is good evidence that the early sex steroid environment has an organizational effect on later sexual partner preference. Research with zebra finches, a pair-forming species, shows a likely early estrogenic organizational hormone effect on pairing partner preference, an effect that can also interact with the early social environment to determine adult pairing preference. Experiments with two amphibian and fish species suggest that activational hormone effects (effects of the hormone milieu in adulthood) may regulate sexual partner preference. As a complement to the research on hormonal involvement, a growing body of theoretical and empirical research addresses the possible adaptive functions of the same-sex sexual and pairing behavior observed in many wild animals. Such advances have important implications for conceptualizing neuroendocrine mechanisms of partner preferences.

High-resolution behavioral time series of Japanese quail within their social environment

The behavioral dynamics within a social group not only could depend on individual traits and social-experience of each member, but more importantly, emerges from inter-individual interactions over time. Herein, we first present a dataset, as well as the corresponding original video recordings, of the results of 4 behavioral tests associated with fear and aggressive response performed on 106 Japanese quail. In a second stage, birds were housed with conspecifics that performed similarly in the behavioral tests in groups of 2 females and 1 male. By continuously monitoring each bird in these small social groups, we obtained time series of social and reproductive behavior, and high-resolution locomotor time series. This approach provides the opportunity to perform precise quantification of the temporal dynamics of behavior at an individual level within different social scenarios including when an individual showing continued aggressive behaviors is present. These unique datasets and videos are publicly available in Figshare and can be used in further analysis, or for comparison with existing or future data sets or mathematical models across different taxa.

Semen biotechnology optimization for successful fertilization in Japanese quail (Coturnix japonica)

Among the reproductive biotechnologies needed to improve Japanese quail conservation and valorization, optimized conditions of semen methodologies including sampling, treatment, and artificial insemination are a prerequisite. However, they have been poorly developed due to specific physiological and behavioral features of the species. The aim of the present study was to optimize them, from semen collection/treatment up to artificial insemination procedures. We studied different parameters including semen preparation (individual/pooled, presence of foam, type and pH of extender) and zootechnical parameters (depth of insemination in the female tract, number of sperm inseminated, insemination frequency). We showed that the separation of semen from individual males was required to optimize fertility, as a prerequisite for future semen cryopreservation. The deleterious effect of mixed foam extract addition on the fertility level was demonstrated. These results highlight parameters involved in male copulatory competitions and in sperm post copulation selection. Furthermore, we took into account extender effects and standardized the zootechnical conditions of insemination. The depth of intravaginal insemination (1 cm) was a key factor, but not the number of sperm inseminated (15-60 million sperm/female). Finally, artificial inseminations with optimized conditions led to successful fertility rates (up to 80%) and a duration of the fertile period equivalent to that obtained by natural mating.

Expression of aggressiveness modulates mesencephalic c-fos activation during a social interaction test in Japanese quail (Coturnix japonica)

It is well known that during a social conflict, interactions are dependent on the animal's propensity to behave aggressively as well as the behavior of the opponent. However, discriminating between these two confounding factors was difficult. Recently, a Social Interaction (SI) test using photocastrated males as non-aggressive stimuli was proposed as a useful tool to evaluate aggressiveness. The avian Intercollicular- Griseum centralis complex (comparable to mammalian periaqueductal gray) has been reported as a crucial node in the descending pathways that organize behavioral and autonomic aspects of defensive responses and aggressiveness. Herein, using the SI test, we evaluated whether mesencephalic areas are activated (expressed c-fos) when photostimulated adult males are confronted with non-responsive (non-aggressive) opponents. Furthermore, we also examined whether mesencephalic activation is related to male performance during the SI test (i.e., aggressive vs. non-aggressive males) in birds reared in enriched or in standard environments. Five mesencephalic areas at two anatomic levels (intermediate and rostral) and locomotion during SI testing were studied. Aggressive males showed increased c-fos expression in all areas studied, and moved at faster speeds in comparison to their non-aggressive and control counterparts. Non-aggressive males and the test controls showed similar c-fos labeling. In general, rearing condition did not appear to influence c-fos expression nor behavior during the SI test. Findings suggest that mesencephalic activation is involved when males are actively expressing aggressive behaviors. This overall phenomenon is shown regardless of both the environmental stimuli provided during the birds´ rearing and the potentially stressful stimuli during the SI trial.

Unexpected results when assessing underlying aggressiveness in Japanese quail using photocastrated stimulus birds

Aggressive behaviors can affect both animal welfare and productivity. Because the expression of aggressive behaviors is dependent on the quality of the opponent, they reflect relative rather than absolute levels of underlying aggressiveness. This study was aimed to characterize the aggressive responsiveness of photostimulated (14:10 h light:dark photoperiod) adult Japanese quail when interacting with a photocastrated (6:18 h light:dark photoperiod) counterpart in a novel test environment and to assesses interindividual variations. This was based on the assumption that photocastrated birds will not actively provoke an aggressive confrontation. Birds were reared in male-female pairs. Frequencies of behaviors (i.e., pecks, threats, chases, grabs, mounts) were determined during 10 min social interactions in a novel environment. A first experiment evaluated 78 encounters between a photostimulated male or female with either a photocastrated male or female (photocastration of sexually mature birds started at 11 wk of age). High interindividual variability was observed and in general, highly aggressive birds (performing 20 or more aggressive interactions) received little or no aggression from their test counterpart. However, unexpectedly, we also found that 37% and 32% of photocastrated males and females, respectively, performed aggressions toward their photostimulated counterparts, and initiated the aggressive interactions in a similar proportion than photostimulated males. Aggressive photocastrated males did not perform reproductive-type behaviors (i.e., grabs, mounts). Aggressiveness in the photocastrated birds was attributed to their social experience prior to photocastration. Therefore, a second experiment evaluated 106 encounters between a photostimulated male or female and a naive photocastrated male (photocastration started at 4 wk of age, prior to sexual development). Photocastrated males performed no aggressions toward their photostimulated counterparts. Consistently with previous studies, our findings show that naive photocastrated males can be used as a non-aggressive stimulus during a social interaction aimed to assess expression of aggressiveness in photostimulated birds. However, caution should be taken when applying the photocastration protocol considering that prior fighting and sexual experience or other physiological changes related with maturation can interfere during subsequent aggressive testing.

The effects of phytosterols on the sexual behavior and reproductive function in the Japanese quail (Coturnix coturnix japonica)

Phytosterols (PS) are plant origin sterols naturally found in many foods and added as food additives. Since 1950, PS have attracted considerable attention due to their ability to lower serum cholesterol and inhibit cardiovascular disease (CVD). However, recent studies have found that PS act as endocrine-disrupting chemicals in laboratory animals. Therefore, this study was aimed at finding the mechanism(s) for PS effects on the sexual behaviors and reproductive functions in male Japanese quails (Coturnix coturnix japonica). At 15 d of age, 30 male Japanese quails were randomly assigned to 3 groups for the chronic in-vivo experiment. Animals were gavaged daily with single dose of PS suspension (PS dissolved in medium chain triglyceride [MCT]) into the crop sac from 15-100 d of age. Following maturation, a sexual behavior test, semen collection, and test of fertilization ability were performed. Blood was collected by cervical dislocation at 100 day of age for hormones analysis. To observe the direct effects of PS on the testis, interstitial cells of the normal testes were cultured for 24 h. Ovine-LH (O-LH) was used for half of each group to stimulate interstitial cells for testosterone production. The results showed that chronic doses of PS reduced (P < 0.01) mount and copulation behavior in male quails (primarily in the group receiving 800 mg/kg BW). Both acute in vitro and chronic in vivo experiments revealed a reduction in testosterone (P < 0.05) after PS treatments; concomitantly, Leydig cell numbers were also low (P < 0.05) at a dose of 800 mg/kg BW. Real-time PCR results showed lower expression of 17β-hydroxysteroid dehydrogenase (17β-HSD) at the same dose. The results suggested that feeding large amounts of PS reduced testosterone levels and sexual behavior by affecting Leydig cell proliferation, and cholesterol trafficking, 17β-HSD expression in the testes of male Japanese quail.

To fight or mate? Hormonal control of sex recognition, male sexual behavior and aggression in the gecko lizard

Squamate reptiles are a highly diversified vertebrate group with extensive variability in social behavior and sexual dimorphism. However, hormonal control of these traits has not previously been investigated in sufficient depth in many squamate lineages. Here, we studied the hormonal control of male sexual behavior, aggressiveness, copulatory organ (hemipenis) size and sex recognition in the gecko Paroedura picta, comparing ovariectomized females, ovariectomized females treated with exogenous dihydrotestosterone (DHT), ovariectomized females treated with exogenous testosterone (T), control females and males. The administration of both T and DHT led to the expression of male-typical sexual behavior in females. However, in contrast to T, increased circulating levels of DHT alone were not enough to initiate the full expression of male-typical offensive aggressive behavior and development of hemipenes in females. Ovariectomized females were as sexually attractive as control females, which does not support the need for the demasculinization of the cues used for sex recognition by ovarian hormones as suggested in other sauropsids. On the other hand, our results point to the masculinization of the sex recognition cues by male gonadal androgens. Previously, we also demonstrated that sexually dimorphic growth is controlled by ovarian hormones in P. picta. Overall, it appears that individual behavioral and morphological sexually-dimorphic traits are controlled by multiple endogenous pathways in this species. Variability in the endogenous control of particular traits could have permitted their disentangling during evolution and the occurrence of (semi)independent changes across squamate phylogeny.

An individually fitted physical barrier device as a tool to restrict the birds' spatial access: can their use alter behavioral responses?

Social interactions have been extensively studied in poultry in a variety of environmental situations. Many studies allow full social contacts between birds, but there are others in which the interactions are tested through barriers (wire mesh or glass). Thus a situation where, according to their needs, some birds can get access to physical contact with conspecifics while others cannot, would be useful to expand the testing options for social interaction studies. We developed an individual physical barrier device (IPB) that is fitted on the birds to delimit their ambulation areas by preventing them from passing across metal mesh boundaries that IPB free counterparts can easily overcome. The prototypes showing greater efficacy consisted of a small metal bar placed in the bird's back perpendicular to the sagittal plane that slightly exceeds body width, held with a harness fitted by 2 elastic fabric bands around the wings' base. To be useful, the IPB should allow natural movements and not affect the expression of behaviors (non-invasive). This study assessed whether the IPB may alter adult Japanese quail behavioral responses using 4 classical test situations: Open-Field, Runway, Time Budget in Home Box, and Mating Interactions. Open-field ambulatory behaviors were affected 1 h, but not 7 d, after IPB was fitted, suggesting that 7 d (or less) are required to habituate to the device. After that time period, IPB fitted birds showed no differences in any of the behaviors registered in the other 3 tests situations when compared to non IPB fitted birds. Findings suggest that after habituation, the IPB does not affect main behaviors in adult quail. Its application could be expanded if an IPB device is also found suitable for other poultry species.

Hit or Miss: Fertilization Outcomes of Natural Inseminations by Japanese Quail

Variation in fertilization success underlies sexual selection, yet mating does not guarantee fertilization. The relationship between natural inseminations and fertilization success is essential for understanding sexual selection, yet that relationship and its underlying mechanisms are poorly understood in sperm-storing vertebrates such as birds. Here the relationship is analyzed in mating trials using Japanese quail (Coturnix japonica), which show striking variation in the fertilizing success of inseminations. Failures of males’ inseminations to fertilize eggs were mainly due to failures prior to sperm-egg contact. Fertilization probabilities on any given day were unrelated to whether the female had laid an egg the previous day, arguing against stimulation of sperm release from sperm storage tubules by the events of the daily egg-laying cycle. Instead, an unfertilized egg laid between two fertilized eggs predicted a longer sperm storage interval. Both sexes gained similar numbers of fertilized eggs by mating with a second partner the next day, but males, unlike females in a previous study, did not gain by having two females to mate with at the same time. Instead, they were both behaviorally and sperm limited, whereas females gain by mating twice in quick succession. Even double inseminations often failed to fertilize any eggs, and multiple matings would be needed for an entire clutch to be fertilized with high certainty. Paradoxically, this low and probabilistic fertilization success co-occurs with other notable characteristics of male quail suggestive of past sexual selection for increased success, including vigorous copulatory behavior, forced copulations, foamy secretion aiding in sperm competition, large testes and unusual sperm morphology.