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.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.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