J. Poultry Sci. 和文要旨 62巻　2025年

DOI： https://doi.org/10.2141/jpsa.2025007

A Bird’s-Eye Overview of Leptin and Female Reproduction — with Mammalian Comparisons

Sadequllah Ahmadi1, 2 and Takeshi Ohkubo1
1 College of Agriculture, Ibaraki University, 3-21-1 Chuo, Ami, Ibaraki 300-0393, Japan
2Faculty of Animal Science, Afghanistan National Agricultural Sciences and Technology University (ANASTU),Kandahar 3801, Afghanistan

抄録 Leptin, a key regulator of reproductive physiology, influences various processes in vertebrates, including oocyte proliferation, embryogenesis, the onset of puberty, ovarian function, and follicle development. In mammals, leptin affects steroidogenesis, folliculogenesis, and hormonal regulation through the hypothalamic-pituitary-gonadal axis. Instead, in avian species, leptin-controlled mechanisms are poorly understood, because birds do not produce leptin in adipocytes. In birds, leptin is expressed in the brain, pituitary glands, and gonads, where it enhances ovarian function and egg-laying performance, particularly during feed deprivation. In this review, we discuss and summarize the recently discovered role of leptin in regulating ovarian function during different life stages in birds and compare it with its function in mammals.

DOI： https://doi.org/10.2141/jpsa.2025007

DOI： https://doi.org/10.2141/jpsa.2025013

Function of Amino Acids and Neuropeptides in Feeding Behavior in Chicks

Phuong V. Tran1,†
1 Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Science, Kyushu University, Fukuoka 819-0395, Japan
† Present address: Department of Animal Nutrition and Feed, National Institute of Animal Science, Hanoi, Viet Nam

Regulation of food intake, especially during the neonatal period, is important to ensure optimal nutrition and meet the metabolic requirements of growing and healthy animals. However, many problems associated with neonatal chicks remain unsolved. Feeding behavior during the neonatal stage is characterized by short resting periods between very brief times spent taking up food. Accordingly, neuropeptides, which take time to synthesize and release, as well as nutrients that are taken up via feeding, may be involved in feeding regulation. The present review summarizes current knowledge about the role of amino acids and their interaction with neuropeptides on the regulation of food intake in neonatal chicks with special emphasis on L-arginine metabolism and neuropeptide Y. Fasting and subsequent short-term refeeding influence amino acid metabolism in the brain. Short-term refeeding induces a rapid increase in the concentrations of several amino acids, which may contribute to satiety signals in the neonatal chick brain. The function of L-arginine is related to its metabolite, L-ornithine, which acts as an innate satiety signal in the control of food intake. Co-injection with L-ornithine attenuates the orexigenic effect of neuropeptide Y in a dose-dependent manner. This implies a potent interaction in the brain between the regulation of food intake by neuropeptide Y and acute satiety signals by L-ornithine. The roles of other amino acids in feeding and their relationship with the stress response are also discussed in this review. In conclusion, endogenous neuropeptides and endogenous and/or exogenous nutrients such as amino acids are believed to coordinate the feeding behavior of neonatal chicks.
Key words: amino acid, neuropeptide, neonatal chick, feeding behavior, central nervous system

DOI： https://doi.org/10.2141/jpsa.2025013

DOI： https://doi.org/10.2141/jpsa.20250029

近年の人類学・鳥類学的知見に基づく日本における家禽の位置づけ精密化の必要性

筑波大学
田島淳史

家禽の肉および卵は、世界的に見ても日本においても高品質な動物性蛋白質の重要な供給源である。しかし、歴史的視点から見ると、日本における家禽は食料資源としてよりも、むしろ象徴的あるいは精神的な存在として位置づけられてきた時期が長く、家禽の存在は日本人の意識および社会構造の中に深く根付いている。これまでの研究により、ニワトリは約2,000年前の弥生時代に初めて日本列島に出現したと考えられるが、これは大陸から日本列島への渡来人の流入が活発であった時期と符合する。それ以降、日本における家禽は美術、文学、神話、民話など多岐にわたる文化領域において重要な役割を果たしてきた。近年、分子時計解析技術や、化石試料・生体試料を用いた遺伝子の挿入、欠損、突然変異、ウイルス感染などのゲノム変異の検出技術が進展したことにより、人類および動物の移動や分化に関する既存の理論を学際的にかつ継続的に見直す必要性が生じている。そこで本総説は、近年進歩が著しい人類学および鳥類学の知見を概観した上で、日本における人間と家禽との間に存在する独特かつ多層的な関係性を精密化する必要があることを提示する。

Refinement of Poultry Standing in Japan Based on Recent Anthropo-ornithological Perspectives

Atsushi Tajima
University of Tsukuba

抄録 Poultry meat and eggs are important sources of high-quality animal protein worldwide. However, poultry in Japan has historically been regarded as a symbolic or spiritual entity more than as a food source, as its roles are deeply embedded in Japanese consciousness and society.Current evidence indicates that chickens first appeared in Japan during the Yayoi period, approximately 2,000 years ago, coinciding with a period of active human migration to the Japanese archipelago. Since then, poultry has played notable roles in Japanese art, literature, mythology, and folktales. Recent advancements in molecular clock analysis or the detection of genomic modifications, such as introgression, deletions, mutations, and viral infection from trace fossil/live samples necessitate the continual revision and refinement of existing theories about human and animal history across several academic disciplines. Therefore, the objective of the present review was to elucidate the distinct and multilayered relationship between humans and poultry in Japan, incorporating recent anthropological and ornithological perspectives.
Key words: Anthropology, Japan, Ornithology, Poultry

DOI： https://doi.org/10.2141/jpsa.2025029

DOI： https://doi.org/10.2141/jpsa.2025001

Biosecurity Practices for Reducing Antimicrobial Use in Commercial Broiler Farms in Korea

Min Beom Kim and Young Ju Lee
College of Veterinary Medicine & Institute for Veterinary Biomedical Science, Kyungpook National University, Daegu 41556, Republic of Korea

抄録 Farm biosecurity is valuable for reducing the indiscriminate use of antimicrobials. However, its relationship with antimicrobial usage can be difficult to assess because of multiple factors. This study evaluated the impact of biosecurity practices on productivity, frequency of antimicrobial use, and development of antimicrobial resistance. Among factors related to biosecurity, mortality rate <2% within one week of age, survival rate >98%, and production index >350 in farms in which: bedding was not reused or only reused once, regular advice and biosecurity training was provided by poultry veterinarians, distinctions between clean and dirty areas were strictly enforced at all times, workers used farm biosecurity manuals, or disinfection guidelines were fully implemented, including cleaning before introducing new flocks and daily disinfection throughout growth, were significantly higher than those in farms without these measures (p < 0.05). The absence of biosecurity practices increased antimicrobial use to one (25.7%), two (39.2%), and three (25.7%) times (p < 0.05). In farms that implemented biosecurity practices, the antimicrobial administration was significantly increased to two times (44.2%) (p < 0.05), with only 17.4% of farms using antimicrobials three times. The prevalence of environmental Escherichia coli resistant to multiple cephalosporins and chloramphenicol, which are not used on broiler farms, was significantly reduced by biosecurity practices (p < 0.05). Our findings indicate that improved biosecurity practices decrease antimicrobial use, decrease the incidence of antimicrobial-resistant bacteria, and help to eliminate resistant bacteria in farm environments.
Key words: antimicrobials, antimicrobial-resistant bacteria, biosecurity practices, broiler

DOI： https://doi.org/10.2141/jpsa.2025001

DOI： https://doi.org/10.2141/jpsa.2025002

Network Pharmacology Suggests Mechanisms for Therapeutic Effects of Caulis Sinomenii on Avian Gout

Guanyang Li 1, 2 †, Junfei Xu 2 †, Huanhuan Li 2, Wenxin Yan 2, Fengting Chen 2, Anwen Yuan 1 and Juzuo Zhang 1, 2
1 Department of Clinic Veterinary Medicine, College of Veterinary Medicine, Hunan Agricultural University, Changsha 410128, China.
2 College of Biological and Food Engineering/Key Laboratory of Research and Utilization of Ethnomedicinal Plant Resources of Hunan Province/Hunan Provincial Higher Education Key Laboratory of Intensive Processing Research on Mountain Ecological Food, Huaihua University, Huaihua 418000, China

抄録 Avian gout (AG) is detrimental to the survival and production performance of poultry and effective drugs are lacking. Caulis sinomenii has shown clinical efficacy against arthritis and may have potential value in AG prevention and treatment. In the present study, the components and targets of C. sinomenii and AG-related targets were identified using relevant databases. The common targets, target interactions, and signaling pathways involved in the prevention and treatment of AG by C. sinomenii were determined using software to explore the potential mechanisms of action. Sixteen components of C. sinomenii, eight of which were active ingredients with 351 targets and 2993 AG-related targets, were identified using several databases. A total of 156 common targets were associated with 202 biological processes and 34 pathways. Toll-like receptor 4 (TLR4) and prostaglandin endoperoxide synthase 2 were core targets. These targets may exert therapeutic effects on AG through four pathways: the nucleotide-binding oligomerization domain (NOD)-like receptor, mammalian target of rapamycin, TLR, and mitogen-activated protein kinase signaling pathways. In summary, C. sinomenii has potential therapeutic efficacy against AG through multicomponent, multi-target, and multi-pathway mechanisms.
Key words: avian gout, Caulis sinomenii, molecular docking, network pharmacology.

DOI： https://doi.org/10.2141/jpsa.2025002

DOI： https://doi.org/10.2141/jpsa.2025003

Effect of Replacing Inorganic Copper, Zinc, and Selenium with Chelated Minerals on Productive Performance, Nutrient Utilization, Tibia Morphology, and Intestinal Histology of Growing Japanese Quail (Coturnix japonica)

Carlos A. Gaona Rodríguez1, Hugo Bernal Barragán1, Nydia C. Vásquez Aguilar1, Adriana Morales Trejo2, Miguel Cervantes Ramírez2, Cecilia Ramírez Hernández3, Humberto González Rodríguez4, Emilio Olivares Sáenz1 and Jesús J. Hernández Escareño3
1Universidad Autónoma de Nuevo León, Facultad de Agronomía, Francisco I, Madero S/N, Hacienda El Canadá, CP 66050, Gral. Escobedo, NL, México
2Universidad Autónoma de Baja California, Instituto de Ciencias Agrícolas, Álvaro Obregón S/N, Colonia Nueva, CP 21100, Mexicali, BC, México
3Universidad Autónoma de Nuevo León, Facultad de Medicina Veterinaria y Zootecnia, Francisco I, Madero S/N, Hacienda El Canadá, CP 66050, Gral. Escobedo, NL, México
4Universidad Autónoma de Nuevo León, Facultad de Ciencias Forestales, Carretera Nacional No. 85, Cd. Victoria – Monterrey, km 145, CP 67700, Linares, NL, México

抄録 This study evaluated the impact of replacing inorganic mineral sources of Cu, Zn, and Se with chelated organic minerals(OM) on performance, nutrient and mineral utilization rates, and intestinal morphometry in growing Japanese quails (Coturnix japonica). A total of 150 nine-day-old quails were randomly assigned to receive one of the following diets over 4 weeks: CTRL (100% inorganic minerals), OM33 (replacement of 33% inorganic minerals), OM67 (replacement of 67% inorganic minerals), and OM100 (100% organic minerals). Quails fed the OM67 diet exhibited higher (P < 0.05) viability, daily weight gain, and live weight than the other groups, with no significant difference in feed intake or feed efficiency across treatments. The utilization rates of Cu and Fe were lower in the OM33 group. The CTRL group presented the lowest tibial weight (P< 0.05). Growing quails fed the OM67 diet contained the highest intestinal villi in the duodenum, jejunum, and ileum. In conclusion, the partial replacement (up to 67%) of inorganic mineral with OM in the diet of growing quails can enhance their productive performance and intestinal histological traits.
Key words: chelated minerals, growth performance, histology, quail, viability.

DOI： https://doi.org/10.2141/jpsa.2025003

DOI： https://doi.org/10.2141/jpsa.2025004

Histological Changes of the Mucosal Epithelium in the Chicken Intestine during Pre- and Post-Hatching Stages

Md. Al Amin1, Md Badiul Alam2 and Kohzy Hiramatsu3
1Department of Science and Technology, Graduate School of Medicine, Science and Technology, Shinshu University, Kami-ina, Nagano 399-4598, Japan.
2Department of Agriculture, Graduate School of Science and Technology, Shinshu University, Kami-ina, Nagano 399-4598, Japan.
3Laboratory of Animal Functional Anatomy (LAFA), Faculty of Agriculture, Shinshu University, Kami-ina, Nagano 399-4598, Japan

抄録 This study clarified the histological changes in the mucosal epithelium of the chicken intestine during the pre- and posthatching stages. The duodenum, jejunum, ileum, and colorectum were collected from embryos at 15, 17, 18, 19, and 21 days of incubation and from chicks at 1 and 3 days after hatching. Paraffin sections prepared from tissue samples were stained with periodic acid-Schiff followed by alcian blue for histological analysis and to detect goblet cells. Villin and β-actin were detected using double immunofluorescence. Villi with finger-like shape were already observed in embryos after 15 days of incubation, and no obvious change in shape was observed even after hatching. Villous height increased in all intestinal regions as the developmental stage progressed, particularly a few days before and after hatching. Goblet cells first appeared in the epithelium of all intestinal regions after 18 days of incubation. The density of goblet cells rapidly increased from 18 to 21 days of incubation. Both villin and β-actin immunoreactivities were detected at the apical surface of the villous epithelium in all intestinal regions, and villin immunopositivity was stronger in the jejunum and ileum after hatching. These findings indicate that the villi and microvilli of the intestine of broiler chickens show histological changes during few days just before and after hatching. Additionally, the density of goblet cells rapidly increased for a few days before hatching.
Key words: chicken, development, epithelium, histological changes, intestine

DOI： https://doi.org/10.2141/jpsa.2025004

DOI： https://doi.org/10.2141/jpsa.2024005

ニワトリにおけるトレハロースの味覚嗜好性と代謝率

川端二功1,2・酒井美咲子1・村澤宏紀1・小峰佑1・向井和久3・川端由子4

1弘前大学農学生命科学部　弘前市文京町036-8561，
2岩手大学大学院連合農学研究科　盛岡市上田020-8550,
3株式会社林原　岡山市北区下石井700-0907,
4九州大学大学院歯学研究院　福岡市東区馬出812-8582　

トレハロースは2分子のD-グルコースがα,α-1,1グルコシド結合で結合したものである。トレハロースはニワトリの腸内細菌叢で資化され，腸管免疫機能を高めることから，ニワトリの飼料原料として活用されている。一方で，ニワトリにおけるトレハロースの味覚嗜好性や代謝動態は十分に解明されていない。本研究では，ニワトリにおけるトレハロースの味覚嗜好性と代謝特性を明らかにすることを目的とした。短時間飲水試験では，ニワトリは低濃度（0.25 M）のトレハロース溶液を水よりも好んだが，高濃度（0.50 M）のトレハロース溶液は水よりも忌避した。しかし，条件付け味覚嫌悪学習試験を行ったところ，トレハロース溶液（0.25 および0.50 M）に対して味覚嫌悪学習が成立しなかった。飼料にトレハロース粉末を0.5%添加した場合，摂取開始後1時間の飼料摂取量は添加しない場合に比べて有意に増加した。呼気ガス分析により，1.0 Mトレハロース溶液の胃内投与は呼吸商をわずかに増加させることがわかった。さらに，ニワトリのトレハロースの代謝率は約50%であった。これらの結果から，ニワトリはトレハロースの甘味をわずかに感じること，飼料にトレハロースを添加することで食べ始めの摂食量が増加すること，トレハロースを約50％の割合でエネルギー源として利用できることが示唆された。これらの知見は，ニワトリ飼料にトレハロースやトレハロースを含む原料を使用する上で有益な情報となる。
キーワード：ニワトリ, 代謝率, 味覚, トレハロース

Taste Preference and Metabolic Rate of Trehalose in Chickens

Fuminori Kawabata1,2, Misako Sakai1, Hiroki Murasawa1, Yu Komine1, Kazuhisa Mukai3 and Yuko Kawabata4
1Physiology of Domestic Animals, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori 036-8561, Japan
2The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate 020-8550, Japan
3Hayashibara Co., Ltd., Okayama 700-0907, Japan
4Section of Oral Neuroscience, Graduate School of Dental Science, Kyushu University, Fukuoka 812-8582, Japan

Trehalose (Tre) is composed of two molecules of D-glucose joined by an α,α-1,1 glucosidic linkage. Because Tre is utilized by the gut microbiome and enhances gut immunity in chickens, it is used as a feed ingredient. However, taste preference and metabolic dynamics of Tre in chickens are not fully understood. Therefore, in this study, we investigated the taste preference in chickens for Tre and the metabolism of this disaccharide. In a short-term drinking test, chickens preferred low concentrations of Tre solution while avoiding high concentrations. Instead, in a conditioned taste aversion test, chickens did not show taste aversion to Tre, implying that chickens do not have a sufficient taste for Tre. The initial feed intake rate increased when 0.5% Tre was added. Respiratory gas analysis revealed that intragastric administration of 1.0 M Tre weakly increased the respiratory quotient. Furthermore, approximately 50% of Tre was metabolized in chickens. These results suggest that chickens slightly taste the sweetness of Tre. Moreover, adding Tre to feed increases the chickens’ initial appetite, and they use approximately 50% of Tre as an energy source. This information is relevant for using Tre alone or as a supplement in poultry feed.
Key words: chicken, metabolic rate, taste sense, trehalose

DOI： https://doi.org/10.2141/jpsa.2024005

DOI： https://doi.org/10.2141/jpsa.2024008

成長中のブロイラーの成長および視床下部ペプチドの遺伝子発現に及ぼす含水飼料給与の影響

松波知弥1・Zhang Yuhui1・谷口悠二2・樋本清一2・實安隆興1・上曽山博1・本田和久1

1 神戸大学大学院農学研究科　神戸市　657-8501
2 株式会社中嶋製作所　長野市　388-8004　

アニマルウェルフェアの観点から、飢えや渇きからの解放が家禽産業においても求められる。ニワトリにおける飲水調節機構は明らかにされていないが、浸透圧調節と飲水調節の間には密接な関係があると考えられる。本研究の目的は、ウェットフィーディングがニワトリヒナの視床下部における食欲、浸透圧調節、及びストレス関連ペプチドの遺伝子発現に影響を及ぼすかどうかを明らかにすることである。実験1では、ブロイラーのヒナの成長に及ぼす水分混合割合の違いによる影響を調べた。市販飼料1 gあたり0.25 g（20％ウェット飼料）、0.667 g（40％ウェット飼料）、あるいは1.5 g（60％ウェット飼料）の蒸留水を混合して、4日齢のブロイラーヒナに42日齢まで給与した。その結果、40%ウェット飼料はヒナの体重、むね肉、およびももの重量を有意に増加させた。実験2では、7日齢のブロイラーヒナに市販のスターター飼料または40%ウェット飼料を21日齢まで給与した。その結果、体重、むね肉、およびももの重量はウェット飼料により有意に増加した。ウェット給餌により給水器中の水重量の減少量は有意に減少した。ニワトリ視床下部における食欲調節ペプチド（ニューロペプチドY、およびα-メラノサイト刺激ホルモン）、浸透圧調節ペプチド（バソトシン、およびメソトシン）、およびストレス関連因子（副腎皮質刺激ホルモン放出因子）をコードする遺伝子のmRNA量には有意な変化は見られなかった。これらの結果から、40％ウェット飼料は成長期のブロイラーの成長を改善するが、飢えや渇きには影響を与えない可能性が示された。我々の結果は、ブロイラー生産におけるウェットフィーディングシステムの実用化は、食肉生産とアニマルウェルフェアの改善に寄与することを示唆するものである。
キーワード：ニワトリ，摂食，神経ペプチド，飲水，含水飼料

Wet Feeding Promotes Growth without Affecting Hypothalamic Peptide Gene Expression in Growing Broiler Chicks

Tomoya Matsunami*1, Yuhui Zhang*1, Yuji Taniguchi2, Sei-ichi Hinomoto2, Takaoki Saneyasu1, Hiroshi Kamisoyama1 and Kazuhisa Honda1
1 Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan
2 Technical Section, Nakajima Seisakusho Co., Ltd., 388-8004, Japan

From the perspective of animal welfare, freedom from hunger and thirst is an undeniable requirement for the poultry industry. Regulatory mechanisms underlying drinking behavior have not yet been identified in chickens; however, the regulation of osmolality and water intake appears to be closely related. This study clarified whether wet feeding affects appetite, osmolality, and stress-related gene expression in the hypothalami of chicks. In Experiment 1, the effects of different wet feed percentages on the growth of broiler chicks were examined. Wet feeds were prepared by mixing either 0.25 g (20% wet feed), 0.667 g (40% wet feed), or 1.5 g (60% wet feed) of distilled water per g of commercial feed. Then, the wet feeds were offered to 4-day-old broiler chicks until 42 d of age. Forty percent wet feed significantly increased body, breast, and leg weights. In Experiment 2, 7-day-old broiler chicks were given either commercial starter feed or 40% wet feed until 21 d of age. Again, weights of the body, breasts, and legs were significantly increased by wet feeding. The total amount of water loss in the individual waterers was significantly decreased by wet feeding. No significant changes were observed in mRNA levels of the genes encoding appetite-regulatory peptides (neuropeptide Y and α melanocyte-stimulating hormone), osmoregulatory peptides (vasotocin and mesotocin), or stress-related peptides (corticotrophin-releasing factor) in the chicken hypothalamus. Overall, 40% wet feed improved growth without inducing thirst or hunger in broiler chicks. These findings suggest that wet feeding contributes to both meat yield and animal welfare during broiler production. Key words: chicken, feed intake, neuropeptides, water intake, wet feed

DOI： https://doi.org/10.2141/jpsa.2024008

DOI： https://doi.org/10.2141/jpsa.2025009

Investigation of Intestinal Health in Broiler Chickens Following　Salmonella Typhimurium and Coccidiosis Vaccination and Challenge with Salmonella Typhimurium

Andrea Pietruska1, Kenneth S. Macklin2, Xu Wang1, James T. Krehling1, Teresa Dormitorio3 and　Rüdiger Hauck1,3
1Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA
2Department of Poultry Science, College of Agriculture and Life Sciences, Mississippi State University, Mississippi State, MS, 39762, USA
3Department of Poultry Science, College of Agriculture, Auburn University, Auburn, AL 36849, USA

抄録 Salmonella enterica and coccidia (Eimeria spp.) are important intestinal pathogens in broiler production. Salmonella has high zoonotic potential, and coccidia are responsible for large economic losses. Live vaccines reduce shedding of Salmonella and minimize the impact of coccidial infections on broiler performance. This study investigated the interaction between both vaccines on the intestinal health of broilers. The 2 × 2 experimental design included vaccination against Salmonella Typhimurium (ST) (no vaccination or vaccination on day 14) and vaccination against coccidiosis (no vaccination or vaccination on day 1). On day 28, all groups were challenged with a ST marker strain resistant to nalidixic acid. Re-isolation of ST from the liver and ceca on day 42 indicated higher susceptibility to systemic infection with ST in birds vaccinated against coccidiosis than that in unvaccinated birds. On day 42, cecal immunoglobulin A (IgA) levels against ST decreased in the group vaccinated against ST and coccidia compared to those in all other groups. IgG antibodies in the cecal contents significantly decreased in the group vaccinated against coccidiosis compared to that of the group vaccinated against ST. There was no difference in systemic IgG levels among groups. Analysis of the cecal microbiota revealed a significant difference in beta diversity on days 28 and 42 between the groups vaccinated against coccidiosis and unvaccinated groups. Functional pathway profiling showed increased activity of pathways associated with carbohydrate and arachidonic acid metabolism in the group vaccinated against ST compared to that in other groups. Gene expression of claudin 1, claudin 4, E-cadherin, β-catenin, and zonula occludens 2 in the cecal wall differed between the groups on days 28 and 42. These findings indicated the significant influence of ST and coccidiosis vaccines on the intestinal health of broilers; however, further studies are required to clarify the implications for health and performance.
Key words: immune response, microbiome analysis, poultry, relative gene expression, transcriptome analysis

DOI： https://doi.org/10.2141/jpsa.2025009

DOI： https://doi.org/10.2141/jpsa.2025010

Effect of betaine on growth performance, methionine metabolism, and methyl transfer in broilers aged 1 to 21 days and fed a low-methionine diet

Heng Wang 1,2, Lin Liu 1,3,4, Xi He 2 and Guozhi Bian 1
1 Animal Husbandry and Fisheries Research Center of Guangdong Haid Group Co., Ltd., Guangzhou 511400, China
2 Hunan Agricultural University, Changsha 410128, China
3 Key Laboratory of Microecological Resources and Utilization in Breeding Industry, Ministry of Agriculture and Rural Affairs, Guangdong Haid Group Co., Ltd., Guangzhou 511400, China
4 Guangdong Haid Animal Husbandry and Veterinary Research Institute Co., Ltd., Guangzhou 511400, China

抄録 Betaine has been proposed as a low-cost source of methyl groups in poultry feed, replacing methionine and choline. The present study aimed to investigate the effect of betaine on growth performance, methionine metabolism, and methyl transfer in broilers aged 1 to 21 days fed a low-methionine diet. A total of 960 one-day-old male broilers were randomly divided into four groups: positive control (0.62% methionine in the diet), negative control (0.37% methionine in the diet), and two treatment groups (0.37% methionine in the diet plus either 1500 or 3000 mg betaine/kg diet). Chicks fed the 1500 mg betaine/kg diet had the highest feed-to-gain ratio (P < 0.05), but no significant difference in final body weight, average daily gain, average daily feed intake, or mortality. Serum S-adenosyl-L-methionine and total homocysteine were higher at 1500 mg betaine/kg diet; whereas serum S-adenosylhomocysteine exhibited the opposite trend. Except for DNA methyltransferase 1, key enzymes and metabolites involved in the hepatic single-carbon pathway showed the highest levels at 1500 mg betaine/kg diet and declined thereafter. Furthermore, betaine promoted dose-dependent mRNA and protein expression of enzymes involved in the hepatic single-carbon metabolic cycle and methyl transferase pathways in chicks fed methionine-deficient diets. In conclusion, while the addition of betaine did not significantly improve the growth performance of chicks aged 1–21 days, inclusion of 1500 mg betaine/kg diet effectively stabilized methionine metabolism and methyl transfer in methioninedeficient diets.
Key words: betaine, methionine deficiency, single-carbon metabolism

DOI： https://doi.org/10.2141/jpsa.2025010

DOI： https://doi.org/10.2141/jpsa.2025011

オピオイドペプチド、バソトシン、メソトシン、及び副腎皮質刺激ホルモン放出因子の中枢投与がニワトリヒナの飲水に及ぼす影響

Zhang Yuhui・村田薫子・竹垣淳也・實安隆興・本田和久

神戸大学大学院農学研究科　神戸市　657-8501

アニマルウェルフェアの観点から、渇きからの解放が家禽産業において求められている。しかしながら、ニワトリにおける飲水調節機構は明らかにされていない。ヒトにおいては、血液浸透圧の上昇が最も強い飲水のシグナルと考えられている。浸透圧上昇のシグナルであるアンジオテンシンⅡはニワトリの飲水を誘導し、その効果はオピオイド受容体アンタゴニストによって緩和される。バソトシンとメソトシンはニワトリの浸透圧調節に関与すると考えられている。絶水はラットの脳の副腎皮質刺激ホルモン放出因子（CRF）ニューロンを活性化し、CRFの中枢投与ははウサギの飲水を誘導する。本研究では、ニワトリヒナの渇きを誘導する神経ペプチドを特定する目的で、オピオイドペプチド、バソトシン、メソトシン及びCRFの中枢投与が飲水に及ぼす影響を調べた。8日齢のニワトリオスヒナに生理食塩水かオピオイドペプチドを脳室内に投与した。飲水量は、飼料を給餌しない条件下で投与120分後に測定した。-オピオイド受容体のアゴニストであるMet-エンケファリンとβ-エンドルフィン、-オピオイド受容体とオピオイド受容体様タンパク質のアゴニストであるノシセプチンの脳室内投与はヒナの飲水を有意に抑制したが、-オピオイド受容体のアゴニストであるダイノルフィンB、並びに -オピオイド受容体のアゴニストであるエンドモルフィン-1及び2は飲水に影響しなかった。バソトシン、メソトシン及びCRFの脳室内投与はヒナの飲水を有意に抑制した。これらの結果から、本研究に用いた神経ペプチドは、いずれも渇きを誘導するペプチドとしては働かないことが示唆された。
キーワード：ニワトリ，飲水，ICV，神経ペプチド，渇き

Yuhui Zhang, Kaoruko Murata, Junya Takegaki, Takaoki Saneyasu and Kazuhisa Honda
Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan

抄録 Freedom from thirst is an undeniable requirement of the poultry industry. However, the regulatory mechanisms underlying water intake in chicks are not yet fully understood. In humans, increased blood osmolality is probably the strongest signal for drinking. Angiotensin II, a hyperosmotic signal, induces water intake in chickens; this effect is attenuated by an opioid receptor antagonist. Vasotocin and mesotocin appear to have osmoregulatory functions in chicken. Dehydration activates brain corticotrophin-releasing factor (CRF) neurons in rats, and the central administration of CRF induces water intake in rabbits. This study aimed to clarify the effects of neuropeptides such as opioid peptides, vasotocin, mesotocin, and CRF on water intake to identify thirst-inducing neuropeptides in chicks. Eight-day-old male chicks were intracerebroventricularly injected with saline or the peptides. Water intake was measured 120 min after the injection under feed-deprived conditions. Intracerebroventricular administration of Met-enkephalin (a δ-opioid receptor agonist), β-endorphin (a δ-opioid receptor agonist), and nociception (a κ-opioid receptor and opioid receptor-like protein agonist) significantly suppressed water intake in chicks, whereas dynorphin B (a κ-opioid receptor agonist) and endomorphin-1 and 2 (μ-opioid receptor agonists) did not affect water intake. Intracerebroventricular administration of vasotocin, mesotocin, and CRF significantly suppressed water intake in chicks. Our findings suggest that none of the neuropeptides used in this study function as thirst-inducing peptides in the central nervous system of chicks.
Key words: chicken, drinking, ICV, neuropeptides, thirsty

DOI： https://doi.org/10.2141/jpsa.2025011

DOI： https://doi.org/10.2141/jpsa.2025012

Effect of a Unique Dwarfism on Growth, Production, and Reproduction Performance of the Nicobari Chicken Breed

Santosh Haunshi, Shanmugam Murugesan, Prince L.L. Leslie, Rajkumar Ullengala and Chatterjee R. Nath
ICAR-Directorate of Poultry Research, Rajendranagar, Hyderabad-500030, Telangana, India

抄録 The present study aimed to determine the inheritance and effect of dwarfism, which occurs naturally in the Nicobari chicken breed, on various growth and production traits. The dwarf character did not affect body weight for up to 4 weeks; but had a negative impact from 8 weeks onward, with body weight declining by 5.5%–9.0% in males and 9.0%–16% in females. Shank length was 22% and 27% shorter in male and female dwarf birds, respectively, than in full-size birds. The average age at first egg was 3.08% higher in dwarf hens than in their normal counterparts, and was accompanied by a non-significant decline (5.63%) in 40 weeks egg production. Egg weights were 2.23% and 2.64% lower at 32 and 40 weeks, respectively, in dwarf hens. Instead, the shape index and shell thickness were better in dwarf hens. The eggs of dwarf hens were darker and red, with less hue than those of normal hens; whereas internal egg quality was the same. Fertility and hatchability were lower in dwarf dams mated with dwarf sires than in crosses or reciprocal crosses between normal and dwarf birds. Breeding experiments and sequencing of transmembrane protein 263 ruled out the sex-linked (dw) and autosomal dwarfism (adw), as the genetic causes of dwarfism in the Nicobari breed, which instead appears to follow a novel pattern and has a unique effect on growth traits.
Key words: dwarfism, egg quality, Nicobari breed, production, reproduction

DOI： https://doi.org/10.2141/jpsa.2025012

DOI： https://doi.org/10.2141/jpsa.2025014

ブロイラーの胸筋と烏口上筋の筋腱膜接合部の損傷と線維化

川崎　武志1・岩﨑智仁2・渡邉敬文3・山田未知4・前田 尚之2・長谷川靖洋2・髙橋 直紀3・小林 良祐3

1人と鳥の健康研究所　網走市鱒浦　099-3119
2酪農学園大学農食環境学群食と健康学類　江別市文京台緑町　069-8501
3酪農学園大学獣医学群獣医学類　江別市文京台緑町　069-8501
4酪農学園大学農食環境学群循環農学類　江別市文京台緑町　069-8501

　本研究は、筋組織の変性と線維化の発生メカニズムを明らかにすることを目的として、ブロイラー飼料を自由摂取させたニワトリ（ROSS308）（Bro）10羽と，ブロイラー飼料よりも代謝エネルギーが低い飼料を制限給餌したニワトリ（ROSS308）（Adj）10羽の胸筋と烏口上筋について肉眼的・組織学的に観察比較した。48日齢でのBroとAdjの体重の中央値は，それぞれ4.9kgと0.9kgであった。Broは雌雄ともに股間が広く，後肢が外転する傾向があり，直立姿勢が前傾することが多く，不安定であった。特に，平均値よりも体重が大きいBroの2羽のオスは，起立歩行時に著しく安定性を欠き，バランスを保つために激しく羽ばたくことが多かった。組織学的には、主に胸筋と烏口上筋の筋腱膜接合部で筋線維の損傷と線維化が観察された。筋線維の損傷と線維化は筋腱膜接合部から離れた領域で軽減していた。しかし，体重が大きい2 羽のオスでは，筋組織の線維化が筋腱膜接合部から離れた領域でも認められた。一方，Adj の胸筋と烏口上筋の筋腱膜接合部では，筋線維の変性や筋組織の線維化はほとんど認められなかった。また，Bro の うち1 羽の烏口上筋では，筋組織の凝固壊死と壊死筋組織を包囲するように顕著な線維組織が発達していた。この線維組織には、不規則な形状と顕著な分岐を持つ不完全な血管が多数増殖していた。これらの所見は、筋腱膜接合部の損傷と異常な毛細血管増殖が、胸筋と烏口上筋の顕著な線維化を伴う病変の形成に密接に関連している可能性があることを示唆している。

Injury and Fibrosis at the Myoaponeurotic Junction of Pectoralis Major and Supracoracoideus Muscles in Broiler Chickens
Takeshi Kawasaki1, Tomohito Iwasaki2, Takafumi Watanabe3, Michi Yamada4, Naoyuki Maeda2, Yasuhiro Hasegawa2, Naoki Takahashi3, and Ryosuke Kobayashi3
1 Research Office Concerning the Health of Humans and Birds, Abashiri, 099-3119, Japan
2 Department of Food Science and Human Wellness, Rakuno Gakuen University, Ebetsu, 069-8501, Japan
3 Department of Veterinary Anatomy, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, 069-8501, Japan
4 Department of Sustainable Agriculture, Rakuno Gakuen University, Ebetsu, 069-8501, Japan

抄録 In this study, we aimed to identify the mechanism responsible for tissue degeneration and fibrosis in pectoral and supracoracoideus muscles. Ten chickens fed ad libitum broiler feed (Bro) were compared to 10 chickens fed breeding feed (Adj), which has lower metabolizable energy. The median body weight of Bro and Adj birds at 48 days of age was 4.9 and 0.9 kg, respectively. In Bro birds, hind legs were farther apart and tended to abduct, whereas their standing posture was often tilted forward, making them unstable. The two Bro males were heavier than the average, markedly less stable when standing or walking, and often flapped their wings vigorously to maintain balance. Myofiber damage and fibrosis were observed at the myoaponeurotic junction of the pectoralis major and supracoracoideus muscles in Bro birds. Myofiber damage and fibrosis were detected also in areas distal to the myoaponeurotic junction in the two heavier males but were otherwise less evident. By contrast, in Adj birds, almost no degeneration or fibrosis of muscle tissue was observed at the myoaponeurotic junction. In addition, the supracoracoideus muscle of one of the Bro birds showed coagulative necrosis of muscle tissue, surrounded by prominent fibrous tissue. Numerous incompletely formed blood vessels with irregular shapes and prominent branching proliferated in the fibrous tissue. These findings suggest that injury at the myoaponeurotic junction and abnormal capillary proliferation may be closely related to the formation of lesions, along with prominent fibrosis in the pectoralis major and supracoracoideus muscles.
Key words: broilers, fibrosis, myoaponeurotic junction, pectoralis major muscles, supracoracoideus muscles, wooden breast

DOI： https://doi.org/10.2141/jpsa.2025014

DOI： https://doi.org/10.2141/jpsa.2025015

Effect of Dietary Energy Levels on the Reproductive Performance in Breeding Pigeons, and Growth Performance and Intestinal Health in Squabs

Kang Cheng1, Jingyi Niu1, Daizi Hu1, Jinxiu Yao1, Hongyue Zhao2, Mingjun Yang3, Jinrong Wang1 and Yong Zhang1
1School of Biological Engineering, Henan University of Technology, Zhengzhou 450001, People’s Republic of China
2School of International Education, Henan University of Technology, Zhengzhou 450001, People’s Republic of China
3Henan Tiancheng Pigeon Industry Co., Ltd., Wugang 462500, People’s Republic of China

抄録 The present study evaluated the effect of different dietary energy levels on reproductive performance in breeding pigeons, as well as growth performance and intestinal health in squabs. In total, 180 pairs of 12-month-old White King breeding pigeons were randomly assigned to five dietary treatments, each with six replicates of six pairs of birds, and fed diets containing 11.60, 11.80, 12.00, 12.20, and 12.40 MJ/kg for 46 days, respectively. Energy content beyond 12.00 MJ/kg shortened the laying interval (linear and quadratic, P<0.05), while boosting 38-day, 42-day, and 46-day laying rates (linear, P<0.05) in breeding pigeons. Except for the early stage of lactation, feed intake showed a linear and/or quadratic negative relationship with dietary energy content (P<0.05). Body weight at 1 week of age, average daily gain during the early growth stages, and serum total protein of squabs increased with increasing dietary energy content (linear, P<0.05); whereas alanine aminotransferase activity decreased (quadratic, P<0.05). Jejunal villus height and villus height to crypt depth ratio in squabs increased with increasing dietary energy levels (linear and quadratic, P<0.05), particularly in the 12.40 MJ/kg group. Higher dietary energy content increased jejunal malondialdehyde content (linear, P<0.05), total superoxide dismutase (T-SOD), and glutathione peroxidase activities (linear, P<0.05), as well as ileal T-SOD (linear and quadratic, P<0.05) and catalase (quadratic, P<0.05) activities in squabs. Hence, intakes greater than 12.00 MJ/kg altered the jejunal redox status. Finally, higher dietary energy content improved reproduction in breeding pigeons and intestinal morphology in squabs. Overall, 12.00 MJ/kg strikes the right balance as it promotes reproductive performance in breeding pigeons and intestinal health in squabs.
Key words: dietary energy levels, reproductive performance, breeding pigeons, growth performance, intestinal health, squabs

DOI： https://doi.org/10.2141/jpsa.2025015

DOI： https://doi.org/10.2141/jpsa.2025016

ニワトリヒナの間脳、腎臓、肝臓、および胸筋において浸透圧ストレスが誘導する遺伝子発現

ZHANG Yuhui・村田薫子・竹垣淳也・實安隆興・本田和久

神戸大学大学院農学研究科　神戸市　657-8501

　鳥類が水分を獲得するにあたり、内因性の水産生は重要な反応である。例えば、渡り鳥ではタンパク質と脂質が主要な水の供給源となる。しかし、鳥類の体液バランスの調節におけるタンパク質と脂質代謝関連遺伝子の役割については調べられていない。本研究では、ヒナの体液調節におけるタンパク質および脂質代謝関連遺伝子の役割を明らかにすることを目的とした。実験1では、12時間の水欠乏がタンパク質および脂質代謝関連遺伝子のmRNA量と飼料摂取量に及ぼす影響を調べた。飼料摂取量は実験期間を通じて絶水により有意に減少した。間脳におけるバソトシンのmRNAレベルは絶水により有意に増加した。ミトコンドリア脂肪酸酸化の律速酵素であるカルニチンパルミトイルトランスフェラーゼ1A（CPT1A）のmRNA量は、肝臓、浅胸筋、および間脳において、絶水により有意に増加した。また、ユビキチン-プロテアソーム系の調節酵素であるアトロジン-1のmRNA量は、浅胸筋において絶水により有意に増加した。一方、脂肪酸合成の律速酵素である脂肪酸合成酵素のmRNA量は、肝臓で絶水により有意に減少した。実験2では、飼料と水を与えない条件下で高張液の腹腔内投与の影響を調べた。投与1時間後、腎臓アクアポリン1、浅胸筋アトロジン-1、間脳CPT1AのmRNA量は高張液投与により有意に増加した。これらの結果から、浸透圧ストレスがニワトリの骨格筋におけるタンパク質異化および間脳における脂肪酸異化を誘導する可能性が示唆された。
キーワード：絶水，飲水，浸透圧，塩化ナトリウム

Osmotic Stress-induced Gene Expression in the Diencephalon, Kidney, Liver, and Breast Muscle of Chicks
Yuhui Zhang, Kaoruko Murata, Junya Takegaki, Takaoki Saneyasu and Kazuhisa Honda
Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan

抄録 Endogenous water production is an important response for inducing water acquisition in birds, with proteins and lipids being major sources of endogenous water. However, the roles of protein and lipid metabolism-related gene expression in the regulation of their body fluid balance have not been investigated. This study aimed to clarify the roles of protein and lipid metabolism-related genes in osmoregulation in chicks. In Experiment 1, we examined the effects of 12 h of water deprivation on the mRNA levels of protein and lipid metabolism-related genes and feed intake in chicks. Feed intake was significantly decreased by water deprivation throughout the experimental period. The mRNA levels of vasotocin in the diencephalon were significantly increased by water deprivation. The mRNA levels of carnitine palmitoyltransferase 1A (CPT1A), the rate-limiting enzyme of mitochondrial fatty acid oxidation, were significantly increased by water deprivation in the liver, breast muscle, and diencephalon of the chicks. The mRNA levels of atrogin-1, a regulatory enzyme of the ubiquitin proteasome-system, were significantly increased by water deprivation in the breast muscle of the chicks. In contrast, the mRNA levels of fatty acid synthase, the rate-limiting enzyme of fatty acid synthesis, were significantly decreased by water deprivation in the liver of the chicks. In Experiment 2, the effects of intraperitoneal administration of hypertonic saline were examined under feed and water-deprived conditions. The mRNA levels of renal aquaporin 1, breast muscle atrogin-1, and diencephalon CPT1A were significantly increased 1 h after hypertonic saline injection. These results suggest that osmotic stress may induce protein catabolism in the skeletal muscle and fatty acid catabolism in the diencephalon of the chicks.
Key words: dehydration, drink, osmolality, sodium chloride

DOI： https://doi.org/10.2141/jpsa.2025016

DOI： https://doi.org/10.2141/jpsa.2025017

Optimizing Standardized Ileal Digestible Methionine Requirements of White Pekin Ducks in the First 21 Days Post-Hatch

Nuwan C. Chathuranga#, Myunghwan Yu#, Yu-Bin Kim, Hyun-Min Cho, Shan R. Nawarathne, Elijah O. Oketch and Jung-Min Heo
Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 34134, Republic of Korea.

抄録 The current study investigated the optimal standardized ileal digestible (SID) methionine (Met) requirement for the growth performance of white Pekin ducks from hatching to 21 days of age. A total of 288 one-day-old male white Pekin ducklings were initially weighed and randomly assigned to six dietary groups, with six replicates per group. Eight ducklings were housed in each floor cage, pre-littered with rice hulls. Basal diets (corn-soybean-based) included 0.30%, 0.35%, 0.40%, 0.45%, 0.50%, and 0.55% SID Met, representing the dietary treatment groups. Ducklings were offered unrestricted access to experimental diets and freshwater for the duration of the study. Body weight and feed intake were recorded weekly, and the average daily gain and feed conversion ratios were calculated. Overlapping linear- and quadratic-plateau regression models were employed to estimate SID Met requirements. Final body weight, average daily gain, and feed conversion ratios in white Pekin ducks exhibited significant quadratic growth with increasing dietary SID Met concentrations. In conclusion, estimated SID Met requirements for white Pekin ducks from hatching to 21 days, based on an average of linear and quadratic model responses, were determined to be 0.51% for body weight improvement, 0.51% for average daily gain, and 0.50% for feed conversion efficiency. These findings provided invaluable insight into optimized nutritional strategies for early growth performance in white Pekin ducks.
Key words: linear, methionine, quadratic, standardized ileal digestible, white Pekin ducks

DOI： https://doi.org/10.2141/jpsa.2025017

DOI： https://doi.org/10.2141/jpsa.2025018

Effects of Aging on the Microbiota and Inflammatory Status of the Intestinal and Oviductal Mucosa in Laying Hens
Takahiro Nii1, 2, Takumi Sugiura1, Naoki Suzuki1, Naoki Isobe1 and Yukinori Yoshimura1, 3
1 Graduate School of Integrated Science for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, 739-8528, Japan
2Japanese Avian Bioresource Project Research Center, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima, 739-8528, Japan
3Hiroshima Study Center, The Open University of Japan, 1-1-89 Higashisenda, Naka-ku, Hiroshima,730-0053, Japan

抄録 Aging and inflammation of the intestinal and oviductal mucosa reduce egg production in laying hens. In mammals, microbiota changes in the intestine and reproductive mucosa are linked to aging and mucosal inflammation, but this relationship remains unclear in hens. The present study aimed to investigate the impact of aging on microbiota and inflammation in the intestinal and oviductal mucosa of hens. Sixteen White Leghorn hens aged ~280 days (young) and ~730 days (aged) were used. Bacterial DNA was extracted from feces and vaginal swabs for 16S rRNA amplicon sequencing. Intestinal (ileum and cecum) and oviductal (uterus and vagina) tissues were processed for histological analysis. Real-time PCR was performed to profile pro- and anti-inflammatory cytokines, tight junction-related molecules, and calbindin in the uterus. Whereas microbial diversity and composition in the vagina did not change with age; alpha-diversity of intestinal bacteria was lower in the aged group, as suggested by 46 genera showing a decrease and five an increase. The morphology of the ileum mucosa deteriorated, with transforming growth factor (TGF)β3 being upregulated and claudin (CLA)3 being downregulated in the intestine of the aged group. Finally, fibrosis progressed with age in the uterine mucosa, along with overexpression of IL-1β, TGFβ3, TGFβ4, and CLA1, but downregulation of calbindin in the oviductal mucosa. These results suggest that aging may impair intestinal and oviductal health through mucosal inflammation in both the intestine and oviduct of laying hens. This change may be related to alterations in the intestinal microbiota but appears less evident in the vagina.
Key words: aging, intestine, microbiota, mucosal barrier, oviduct

DOI： https://doi.org/10.2141/jpsa.2025018

DOI： https://doi.org/10.2141/jpsa.2025019

ニワトリ嗅上皮における嗅覚受容関連分子の遺伝子発現

小山和士1・川端二功1,2,3

1弘前大学大学院農学生命科学研究科　弘前市文京町 036-8561
2弘前大学農学生命科学部　弘前市文京町 036-8561
3岩手大学大学院連合農学研究科, 盛岡市上田 020-8550

　嗅覚は、視覚や味覚と同様に、食べ物の獲得や選別において重要な役割を担っている。ニワトリにおける嗅覚行動は、嗅覚受容体、微量アミン関連受容体、及び嗅覚シグナル伝達分子、などの嗅覚受容関連分子を介して惹起されると推定される。しかし、ニワトリ嗅上皮にそれらの分子が発現しているかどうかについては、あまり知見が蓄積していない。本研究では、嗅覚受容体、微量アミン関連受容体、及び嗅覚シグナル伝達分子の遺伝子がニワトリ嗅上皮に発現しているかどうかをリアルタイムPCRとアガロースゲル電気泳動法で明らかにすることを目的とした。その結果、18の嗅覚受容体、3つの微量アミン関連受容体、6つのシグナル伝達分子の遺伝子発現がニワトリ嗅上皮で確認された。これらの結果は、匂い物質を受容し、嗅覚シグナルを伝達する分子機構をニワトリが有していることを示唆している。
キーワード：ニワトリ, 嗅覚, 嗅覚受容体, 微量アミン関連受容体

Expression of Olfactory Sense-Related Genes in Chicken Olfactory Epithelium
Kazushi Koyama1 and Fuminori Kawabata1,2,3
1Graduate School of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori 036-8561, Japan
2Physiology of Domestic Animals, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori 036-8561, Japan
3The United Graduate School of Agricultural Sciences, Iwate University, Morioka, Iwate 020-8550, Japan

抄録 Olfaction plays a key role in the selection and acquisition of feed as well as its vision and gustation. Although olfactory behavior in chickens is speculated to depend on olfactory receptors, trace-amine-associated receptors (TAARs), and its signaling pathway, insufficient information is available regarding the expression of these molecules in chicken olfactory epithelium. Here, we investigated whether genes encoding representative olfactory receptors, TAARs, and olfactory signaling pathway molecules were expressed in this tissue. Based on real-time quantitative polymerase chain reaction and agarose gel electrophoresis, we confirmed the expression of 18 olfactory receptors, three TAARs, and six signaling pathway genes, suggesting that chickens possess molecular mechanisms for capturing odorants and transducing olfactory signals.
Key words: chicken, olfaction, olfactory receptor, TAAR

DOI： https://doi.org/10.2141/jpsa.2025019

DOI： https://doi.org/10.2141/jpsa.2025006

A Nonsynonymous Single-nucleotide Polymorphism in SLC24A5 Regulates Feather Pigment Deposition in Chinese Yellow Quail

Xiaohui Zhang1, Fanghu Wu1, Yanxia Qi1,2, Yuanyuan Shang1, Lingyun Fan1 and Yifei Wang1
1 College of Animal Science, Henan University of Science and Technology, Luoyang 471003, China
2 Luoyang Key Laboratory of Animal Genetics and Breeding, Luoyang 471003, China

抄録 Plumage color in birds is determined by melanin, whose synthesis and transport are affected by many genes, including specific solute carriers (SLCs). The main objective of this study was to detect polymorphisms in the SLC24A5 gene of the Chinese yellow quail (Coturnix japonica) and analyze their effect on tyrosinase activity in skin tissue and melanin content in down feathers. The cDNA of the SLC24A5 gene was cloned by RT-PCR and subjected to Sanger sequencing. Potential single-nucleotide polymorphisms (SNPs) were screened using multiple sequence alignment. The screened nonsynonymous SNPs were genotyped across 265 Chinese yellow quails using the kompetitive allele-specific PCR method. The association of genotypes with tyrosinase activity in the skin and melanin content in down feathers was analyzed. The g.8884145A/G SNP was identified in exon 9 of the SLC24A5 gene, resulting in an Asp396Ala mutation. The mutant residue was predicted to be located inside the eighth transmembrane helix of the SLC24A5 protein, which is primarily responsible for recognizing Na+/Ca2+ ions. Mutant individuals had significantly lower total melanin content in the feathers and tyrosinase activity in dorsal skin, in spite of no significant difference in SLC24A5 mRNA expression in the same tissues. This study indicates that the g.8884145A/G mutation reduced tyrosinase activity by affecting the function of the SLC24A5 protein, which in turn decreased melanin content of down feathers in Chinese yellow quail.
Key words: Chinese yellow quail, nsSNP, plumage color, SLC24A5, tyrosinase activity

DOI： https://doi.org/10.2141/jpsa.2025006