Circadian clock determines the timing of rooster crowing

SummaryCrowing of roosters is described by onomatopoetic terms such as ‘cock-a-doodle-doo’ (English), ‘ki-ke-ri-ki’ (German), and ‘ko-ke-kok-koh’ (Japanese). Rooster crowing is a symbol of the break of dawn in many countries. Indeed, crowing is frequently observed in the morning [1]. However, people also notice that crowing is sometimes observed at other times of day. Therefore, it is yet unclear whether crowing is under the control of an internal biological clock, or is simply caused by external stimuli. Here we show that predawn crowing is under the control of a circadian clock. Although external stimuli such as light and crowing by other individuals also induce roosters’ crowing, the magnitude of this induction is also regulated by a circadian clock

Study on welfare of laying hens in various housing systems : developments of overall welfare assessment and new modified cage system

近年、動物福祉は思想から法律への具現化を急激に始めており、OIEの世界家畜福祉基準を始めとして、世界各国で法律・ガイドラインが制定されている。EUでは、2012年から産卵鶏のバタリーケージを廃止とする指令が法律として施行され、様々な代替システムが考案されつつある。このような状況において必要とされるのは、各システムの長短所を明瞭化することであり、その短所を解決する改良型飼育システムを開発することである。同時に、高福祉畜産物の差別化のために、各種の飼育システムを現場レベルで評価する福祉評価法を開発することも必須であると言えよう。本研究では、コンベンショナルなケージシステムから最も開放的な放牧まで、代表的な6つの異なる飼育システム（小型・大型バタリーケージ、小型・大型福祉ケージ、平飼い、放牧）を同一機関内に設置して、1年半にわたり約300羽の産卵鶏を継続的に飼育し、各システムの長短所を明瞭化すると同時に、その知見に基づいた福祉評価法および新型飼育システムを開発することを目的とし、以下の5つの実験を実施した。(1)6システムにおけるPecking behaviourの比較［1，2］:まず各システムにおける鶏の行動を詳細に比較検討し、産卵鶏が嘴を使用する合計頻度は、いずれのシステムでも一定であることを見いだした。この結果は、先行研究［3］から立てられた仮説、鶏は何かをつつくという強い動機づけを内在的に保有しているということを強く支持するものであった。すなわち、ケージの産卵鶏は、食草・敷料床つつきを発現できないことによるPecking behaviourの不足分を、餌・自身の羽毛・ケージワイヤーをつつくことで補っている、言い換えればこれらの元となる動機づけは共通していることが明らかとなった。(2)6システムの総合評価［4］:福祉レベル、生産性、免疫反応の評価により、6システムを多面的に評価し、Five freedoms（飢えと渇きからの自由、苦痛・傷害および疾病からの自由、恐怖および苦悩からの自由、物理的不快からの自由、正常行動発現の自由）の観点から長短所を明瞭化した。(1)の結果を考慮して、敷料床つつきなどのPecking behaviourの発現量は、評価指標から除外した。非ケージシステム、特に放牧は、正常行動発現の自由についての評価が高くなる一方で、苦痛・傷害および疾病からの自由についての評価は低くなり、また生産面では卵殻色が薄くなる傾向にあった。小型福祉ケージの総合的な福祉レベルおよび免疫反応は、平飼い・放牧と同等に高かった一方で、大型福祉ケージは、バタリーケージと同様の低い評価であった。(3)福祉評価法の開発［5］:評価の確実性の向上および評価法の推敲・維持の容易さを達成するため、世界中の産卵鶏の福祉研究1000件以上をデータベース化し、それを基に新たな福祉評価法を開発した。さらに、代表的な評価法であるAnimal Needs Index（ANI）との比較および(2)で得られた動物ベースの評価値との関係から、本モデルを評価した。本モデルおよびANI、いずれの評価法も動物ベースの評価値と強い相関関係にあったが、本モデルは、ANIと比較して福祉レベルの検出力が高く、有用性がより高いことが示唆された。(4)新型福祉ケージにおける社会的順位と資源利用の関係［6］:(2)・(3)は、いずれも福祉ケージの高い潜在価値を示していたが、大型福祉ケージにおいては、活動量が増加する一方で、グループサイズの増加により資源競争が激化することを示唆していた。これらの知見と先行研究［7-13］を基に、資源競争を緩和させる資源分散型の中型福祉ケージを新たに考案した。従来型の資源集中型福祉ケージでは、上位個体が砂浴び場を優先利用する一方で、資源分散型では、いずれの順位の個体も同等に利用していた。(5)新型福祉ケージの総合評価［14］:(5)ではさらに、行動・健康状態・生産性からの多面的測定により、資源分散型の中型福祉ケージを総合的に評価した。資源分散型福祉ケージは、行動の多様化・健康状態の改善という福祉ケージの利点を保持しつつも、運動量が増加するという中型ケージの利点を示していた。また、資源集中型福祉ケージと比較すると、砂浴び場への競争が緩和されており、それにより敵対行動が減少し、生産性が高く維持されていた。これらのことから、資源分散型福祉ケージの高い有用性が示された。　以上の実験から、各種飼育システムの長短所を明らかにすると同時に、有用性の高い評価法を開発した。これらの研究は、福祉ケージの高い潜在価値およびケージデザインの重要性を示していた。大型福祉ケージでは、資源競争が激化する短所が見受けられたが、それは資源を分散することで解決されうることが示された。これらの成果は、システムを採用する生産者サイドへ多くの示唆を与えるのみならず、今後の家畜福祉学の発展においても大きく貢献するものと考えられる。発表論文[1]Shimmura et al. Applied Animal Behaviour Science 115,44-54 (2008).[2]Shimmura et al. British Poultry Science 49,396-401 (2008).[3]Shimmura et al. Animal Science Journal 79,128-137 (2008).[4]Shimmura et al. British Poultry Science (in 3rd revision)[5]Shimmura et al. Animal Science Journal (under review).[6]Shimmura et al. Applied Animal Behaviour Science 113,74-86 (2008).[7]Shimmura et al. Animal Science Journal 77,242-249 (2006).[8]Shimmura et al. Animal Science Journal 77,447-453 (2006).[9]Shimmura et al. Animal Science Journal 78,307-313 (2007).[10]Shimmura et al. Animal Science Journal 78,314-322 (2007).[11]Shimmura et al. Animal Science Journal 78,323-329 (2007).[12]Shimmura et al. British Poultry Science 49,516-524 (2008).[13]Shimmura et al. Animal Welfare (in press).[14]Shimmura et al. British Poultry Science (in press).Animal welfare has progressed rapidly from a concept to laws or guidelines around the world. In the EU countries, regulation of animal welfare has been enforced by law, where conventional cages will be banned from 2012, and a variety of housing systems that consider animal welfare have been developed. In such circumstances, fundamental information about the advantages and disadvantages of various housing systems is needed, and development of modified housing systems that resolve the disadvantages is also essential. In addition, to differentiate and sell the stock farm products produced using these systems, welfare assessments evaluating various housing systems at the farm level need to be developed. In this thesis, typical six housing systems (small and large conventional cages, small and large furnished cages, single-tired aviary, free-range) were built in the same place, where about 300 laying hens were managed for one and half year. The advantages and disadvantages of the six housing systems were first clarified, and on the basis of it, a newly modified housing system eliminating the disadvantages and an overall welfare assessment for evaluating various housing systems at farm level were also developed. The five experiments conducted to achieve these objectives were as follows:Chapter 1 (Comparison of pecking behaviour in six housing systems): First, behaviours of laying hens in each system were compared in details, by which it was found that the total frequency of beak use was almost the same regardless of the housing system. This result supports strongly a hypothesis “laying hens have an immanently strong motivation to peck something” framed by our previous study. Namely, caged hens may express the motivation for beak-related behaviour by directing it at food, drinking nipples, their own feathers, and cage wires. In other words, the motivation for beak-related behaviour may be common.Chapter 2 (Multi-factorial investigation of six housing systems): Multi-factorial investigation of six housing systems was conducted by measuring welfare level, productivity, and immune response, and the advantages and disadvantages were clarified from the viewpoint of five freedoms: freedom from hunger and thirst; freedom from discomfort; freedom from pain, injury and disease; freedom to express normal behaviour; and freedom from fear and distress. Considering the result of Chapter 1, the frequencies of pecking behaviours such as litter pecking were excluded from the measurement. The non-cage systems, especially FR, have somewhat low ratings for the freedom from pain, injury, and disease, and some disadvantages for production, such as pale eggs. On the other hand, the rating for the freedom to express normal behaviour was high, and the immune response was high in the non-cage systems. While the total welfare score and the immune response of the small furnished cage were comparable to those of both non-cage systems, the evaluations of the large furnished cage were similar to those of the conventional cages.Chapter 3 (Development of overall welfare assessment): To increase the validity of evaluations and facilitate expansion and maintenance of assessment systems, first a database of more than 1,OOO studies on the welfare of laying hens around the world was constructed. On the basis of it, a science-based welfare assessment was devised. The usefulness of our model was evaluated by comparing it with environment-based Animal Needs Index (ANI) and animal-based measurements of Chapter 2. Assessment using our model was more sensitive than ANI and can be applied to cage systems, which suggests that my model has greater usefulness.Chapter 4 (Relationship between social order and use of resources in new-type furnished cage): The results of both Chapters 2 and 3 indicated the high potential value of furnished cages. However, in large furnished cages, competition for a restricted number of resources was frequently observed due to increased group size, while mobility and comfort behaviour are enhanced by providing a larger total cage area. Based on this result and our previous studies, a medium-sized furnished cage with resources on both sides of the cage (‘separated’ resources) was designed. It was confirmed that hens from each rank used the dust bath equally in medium-size furnished cages with separated resources, while dominant hens had priority for using the dust bath in the furnished cages with localised resources.Chapter 5 (Overall evaluation of new-typed furnished cage): In Chapter 5, the furnished cages with localised resources were evaluated thoroughly by many-sided investigations. The results of increased activity, decreased competition for the dust bath, similar frequency of injurious pecking, and productivity compared to conventional cage were obtained. These results indicate clearly the great usefulness of furnished cages with separated resources. In conclusion, in this thesis, the advantages and disadvantages of various housing systems for laying hens were clarified, and a highly useful welfare assessment system was developed. These results indicated the great potential value and importance of the design of furnished cages. Although the competition for resources was frequently observed in large furnished cages, it can be resolved by separation of resources. These results can provide many suggestions for producers of acceptable housing systems as well as playing a key role in development of animal welfare in the future.博士(学術）麻布大

Chick-computer interaction using sounds

The 11th International Symposium on Adaptive Motion of Animals and Machines. Kobe University, Japan. 2023-06-06/09. Adaptive Motion of Animals and Machines Organizing Committee.Poster Session P4

The quail genome:insights into social behaviour, seasonal biology and infectious disease response

Background: The Japanese quail (Coturnix japonica) is a popular domestic poultry species and an increasingly significant model species in avian developmental, behavioural and disease research. Results: We have produced a high-quality quail genome sequence, spanning 0.93 Gb assigned to 33 chromosomes. In terms of contiguity, assembly statistics, gene content and chromosomal organisation, the quail genome shows high similarity to the chicken genome. We demonstrate the utility of this genome through three diverse applications. First, we identify selection signatures and candidate genes associated with social behaviour in the quail genome, an important agricultural and domestication trait. Second, we investigate the effects and interaction of photoperiod and temperature on the transcriptome of the quail medial basal hypothalamus, revealing key mechanisms of photoperiodism. Finally, we investigate the response of quail to H5N1 influenza infection. In quail lung, many critical immune genes and pathways were downregulated after H5N1 infection, and this may be key to the susceptibility of quail to H5N1. Conclusions: We have produced a high-quality genome of the quail which will facilitate further studies into diverse research questions using the quail as a model avian species

Action spectrum for photoperiodic control of thyroid-stimulating hormone in Japanese quail (Coturnix japonica).

At higher latitudes, vertebrates exhibit a seasonal cycle of reproduction in response to changes in day-length, referred to as photoperiodism. Extended day-length induces thyroid-stimulating hormone in the pars tuberalis of the pituitary gland. This hormone triggers the local activation of thyroid hormone in the mediobasal hypothalamus and eventually induces gonadal development. In avian species, light information associated with day-length is detected through photoreceptors located in deep-brain regions. Within these regions, the expressions of multiple photoreceptive molecules, opsins, have been observed. However, even though the Japanese quail is an excellent model for photoperiodism because of its robust and significant seasonal responses in reproduction, a comprehensive understanding of photoreceptors in the quail brain remains undeveloped. In this study, we initially analyzed an action spectrum using photoperiodically induced expression of the beta subunit genes of thyroid-stimulating hormone in quail. Among seven wavelengths examined, we detected maximum sensitivity of the action spectrum at 500 nm. The low value for goodness of fit in the alignment with a template of retinal1-based photopigment, assuming a spectrum associated with a single opsin, proposed the possible involvement of multiple opsins rather than a single opsin. Analysis of gene expression in the septal region and hypothalamus, regions hypothesized to be photosensitive in quail, revealed mRNA expression of a mammal-like melanopsin in the infundibular nucleus within the mediobasal hypothalamus. However, no significant diurnal changes were observed for genes in the infundibular nucleus. Xenopus-like melanopsin, a further isoform of melanopsin in birds, was detected in neither the septal region nor the infundibular nucleus. These results suggest that the mammal-like melanopsin expressed in the infundibular nucleus within the mediobasal hypothalamus could be candidate deep-brain photoreceptive molecule in Japanese quail. Investigation of the functional involvement of mammal-like melanopsin-expressing cells in photoperiodism will be required for further conclusions

Variation in responses to photoperiods and temperatures in Japanese medaka from different latitudes

Abstract Seasonal changes are more robust and dynamic at higher latitudes than at lower latitudes, and animals sense seasonal changes in the environment and alter their physiology and behavior to better adapt to harsh winter conditions. However, the genetic basis for sensing seasonal changes, including the photoperiod and temperature, remains unclear. Medaka (Oryzias latipes species complex), widely distributed from subtropical to cool-temperate regions throughout the Japanese archipelago, provides an excellent model to tackle this subject. In this study, we examined the critical photoperiods and critical temperatures required for seasonal gonadal development in female medaka from local populations at various latitudes. Intraspecific differences in critical photoperiods and temperatures were detected, demonstrating that these differences were genetically controlled. Most medaka populations could perceive the difference between photoperiods for at least 1 h. Populations in the Northern Japanese group required 14 h of light in a 24 h photoperiod to develop their ovaries, whereas ovaries from the Southern Japanese group developed under 13 h of light. Additionally, Miyazaki and Ginoza populations from lower latitudes were able to spawn under short-day conditions of 11 and 10 h of light, respectively. Investigation of the critical temperature demonstrated that the Higashidori population, the population from the northernmost region of medaka habitats, had a critical temperature of over 18 °C, which was the highest critical temperature among the populations examined. The Miyazaki and the Ginoza populations, in contrast, were found to have critical temperatures under 14 °C. When we conducted a transplant experiment in a high-latitudinal environment using medaka populations with different seasonal responses, the population from higher latitudes, which had a longer critical photoperiod and a higher critical temperature, showed a slower reproductive onset but quickly reached a peak of ovarian size. The current findings show that low latitudinal populations are less responsive to photoperiodic and temperature changes, implying that variations in this responsiveness can alter seasonal timing of reproduction and change fitness to natural environments with varying harshnesses of seasonal changes. Local medaka populations will contribute to elucidating the genetic basis of seasonal time perception and adaptation to environmental changes