反刍动物妊娠期骨骼肌发育及营养调控

反刍动物骨骼肌的生长发育对其生产性能有很大影响,而妊娠期是胎儿骨骼肌发育的重要时期,Wnt、胰岛素样生长因子(IGF)等重要通路/信号因子与胎儿骨骼肌发育密切相关,且母体营养水平在该阶段对胎儿骨骼肌肌纤维发育和脂肪组织生成过程发挥重要的调控作用。因而,本文综述了反刍动物骨骼肌各组分的发育顺序、发生机制以及母体妊娠期营养水平对胎儿骨骼肌发育的影响。     

妊娠母猪的氨基酸营养

母猪的妊娠是一个漫长而复杂的生理过程,妊娠母猪营养供给的合理性直接影响母猪的繁殖性能。由于母猪体内胎儿和自身组织(乳腺等)的不断发育,母体对于饲料中各种营养的需求不断变化,尤其是氨基酸。氨基酸不仅是合成胎儿和母体组织蛋白质的构件物质,同时,特别是在母猪妊娠阶段,一些氨基酸还具有调节特殊生理过程的功能性作用。而且,妊娠母猪的氨基酸需要及理想比率随妊娠期进程而呈动态变化趋势[1]。本文旨在总结氨基酸在提高妊娠母猪繁殖性能、促进胚胎成活与发育方面的研究现状和新发现,探讨妊娠     

妊娠期母体的营养调控与后代健康

妊娠期是胚胎在母体内发育的重要时期,初生幼畜的体况、健康直接影响后期动物的免疫性能和生产性能,而幼畜的健康除受其遗传基因和外部环境的影响外,还受到其胚胎阶段在母体内的发育状况和产后母体的泌乳性能的影响。而妊娠期母体的营养调控直接影响胚胎的发育和产后母畜的泌乳能力。因此研究妊娠期母体的营养调控对后代健康的影响对提高幼畜的成活率和增重速度有重要作用。本文综述了母体妊娠期不同营养调控方式对母体和幼畜健康影响的最新研究进展。     

哺乳动物胎盘营养感应研究进展

妊娠期间母体营养的改变会影响胎儿的生长发育,而胎盘是母体-胎儿间进行气体、营养和代谢物交流的重要枢纽,哺乳动物胎盘营养感应系统响应母体和胎儿营养信号的变化,保证母体健康和胎儿生长发育。鉴于胎盘营养感应系统对哺乳动物繁育的重要性,本文从胎盘营养感应和胎盘养分分配方面综述了哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)、磷酸腺苷活化蛋白激酶(AMP-activated protein kinase,AMPK)、氨基己糖(Hexosamine)信号通路、糖原合成酶3(glycogen synthase kinase,GSK-3)、胰岛素/胰岛素样生长因子(insulin/insulin-like growth factor signaling pathway,IIS)等信号通路及其对妊娠期养分响应和对胎儿发育的影响,以期为哺乳动物的繁育提供参考依据。     

应激对妊娠期母体免疫影响的研究进展

随着集约化养殖的发展,环境应激对动物生长发育和繁殖的影响愈来愈严重,尤其是妊娠期母体应激,将诱发母体情绪紧张,影响胎儿发育,甚至导致流产。其作用机制可能是通过激活神经－内分泌－免疫网络,导致母体全身免疫和子宫局部淋巴细胞、NK细胞数量和活性失调,引起妊娠期母体免疫微环境紊乱,引发胚胎免疫排斥,影响胎儿发育、异常,甚至死亡。作者就应激对妊娠的影响及其作用通路,尤其是应激对妊娠期母体免疫的研究进展进行了综述。     

氨基酸对妊娠母猪繁殖性能的影响及其作用机理(续完)

<正>上期回顾:上期介绍了母猪窝产仔数受影响的因素、养猪生产中胎儿宫内发育迟缓问题、胎盘在胚胎发育中的作用主氨基酸在胎盘生长中的作用。5氨基酸对胎儿肌肉和脂肪组织生长发育的影响研究表明,妊娠期间母体的蛋白质营养会影响出生后仔猪的肌肉生长和肌内脂肪的含量(Rehfeldt等,2004)。肌细胞和脂肪细胞来源于普通的造血前体细胞     

种蛋注射在家禽营养表观遗传学上的应用

胚胎期是表观基因组重编程的关键时期,易受营养物质等外界环境的影响。与哺乳动物不同,家禽的胚胎发育与母体分离,可借助种蛋注射研究营养物质对胚胎发育的影响。本文简述了种蛋注射的研究现状,结合胚胎期表观基因组的重编程机理,阐述了其在研究家禽营养表观遗传学上的重要作用。     

妊娠的细胞免疫调节

胎儿对母体而言是一种同种异体的移植物 ,但却能在母体子宫正常发育、生长 ,其中包含着复杂的免疫调节机制 ,细胞免疫调节乃是一个重要的方面。本文对子宫局部免疫细胞的种类、分布及其在妊娠期的变化和功能 ,免疫营养学说 ,妊娠对子宫局部淋巴细胞的调节 -免疫抑制等方面的研究进行了综述。     

牛、羊妊娠期延长的分析、诊断和治疗

家畜的妊娠期不尽一致,但每种家畜的妊娠期都有一个大致的范围,如荷斯坦牛为279天、夏洛来牛为287天、瘤牛为296天、绵羊为144~150天。家畜妊娠期受品种、胎儿性别、胎儿数量、胎次及胎儿基因型的影响,环境因素,包括营养、外界温度及季节变化,影响较小,品种对妊娠期长短影响最大。在某些致病因素的作用下可导致牛、羊妊娠期延长,如胎儿死亡和胎儿畸形都可致其妊娠期延长。当牛群或羊群中发生妊娠期延长的病例时,应全面调查,找出原因,进行确切诊断,进而选择可行的治疗措施。     

浅谈对孕畜的用药问题

水能载舟,亦能覆舟;药能治病,亦能致命。所以,用药要因病因畜而异。现对孕畜的用药问题,谈谈个人的粗浅看法,供同道参考。(一)胎儿与母体的关系母畜在妊娠期间,胎儿在子宫内生长发育,是通过胎盘与母体进行物质交换的。当胎盘的血液循环发生障碍时,可以引起胎儿缺氧,甚至死亡。胎儿还通过胎盘的渗透作用,从母体摄取营养物质和排泄代谢产物。胎儿在母体内发育,使孕畜既要维持自身的生理活动,又要满足胎儿的营养及代谢需要,这样一来,母     

Maternal periconceptual nutrition,early pregnancy,and developmental outcomes in beef cattle

The focus of this review is maternal nutrition during the periconceptual period and offspring developmental outcomes in beef cattle, with an emphasis on the first 50 d of gestation, which represents the embryonic period. Animal agriculture in general, and specifically the beef cattle industry, currently faces immense challenges. The world needs to significantly increase its output of animal food products by 2050 and beyond to meet the food security and agricultural sustainability needs of the rapidly growing human population. Consequently, efficient and sustainable approaches to livestock production are essential. Maternal nutritional status is a major factor that leads to developmental programming of offspring outcomes. Developmental programming refers to the influence of pre-and postnatal factors, such as inappropriate maternal nutrition, that affect growth and development and result in long-term consequences for health and productivity of the offspring. In this review, we discuss recent studies in which we and others have addressed the questions, “Is development programmed periconceptually?” and, if so, “Does it matter practically to the offspring in production settings?” The reviewed studies have demonstrated that the periconceptual period is important not only for pregnancy establishment but also may be a critical period during which fetal, placental, and potentially postnatal development and function are programmed. The evidence for fetal and placental programming during the periconceptual period is strong and implies that research efforts to mitigate the negative and foster the positive benefits of developmental programming need to include robust investigative efforts during the periconceptual period to better understand the implications for life-long health and productivity.     

Board-invited review: intrauterine growth retardation: implications for the animal sciences

Intrauterine growth retardation (IUGR), defined as impaired growth and development of the mammalian embryo/fetus or its organs during pregnancy, is a major concern in domestic animal production. Fetal growth restriction reduces neonatal survival, has a permanent stunting effect on postnatal growth and the efficiency of feed/forage utilization in offspring, negatively affects whole body composition and meat quality, and impairs long-term health and athletic performance. Knowledge of the underlying mechanisms has important implications for the prevention of IUGR and is crucial for enhancing the efficiency of livestock production and animal health. Fetal growth within the uterus is a complex biological event influenced by genetic, epigenetic, and environmental factors, as well as maternal maturity. These factors impact on the size and functional capacity of the placenta, uteroplacental blood flows, transfer of nutrients and oxygen from mother to fetus, conceptus nutrient availability, the endocrine milieu, and metabolic pathways. Alterations in fetal nutrition and endocrine status may result in developmental adaptations that permanently change the structure, physiology, metabolism, and postnatal growth of the offspring. Impaired placental syntheses of nitric oxide (a major vasodilator and angiogenic factor) and polyamines (key regulators of DNA and protein synthesis) may provide a unified explanation for the etiology of IUGR in response to maternal undernutrition and overnutrition. There is growing evidence that maternal nutritional status can alter the epigenetic state (stable alterations of gene expression through DNA methylation and histone modifications) of the fetal genome. This may provide a molecular mechanism for the role of maternal nutrition on fetal programming and genomic imprinting. Innovative interdisciplinary research in the areas of nutrition, reproductive physiology, and vascular biology will play an important role in designing the next generation of nutrient-balanced gestation diets and developing new tools for livestock management that will enhance the efficiency of animal production and improve animal well being.     

饲料油菜生物学特性及应用研究进展

饲料油菜蛋白质含量高、青饲产量大,可用作多种草食动物的青绿饲料。文章主要就双低饲料油菜的品种特性、利用价值及在动物养殖业中应用等研究状况进行概述,以期为牧草资源开发与草食动物养殖业生产提供科学参考。     

放牧对家畜及畜产品的影响

家畜放牧饲养符合草食家畜的生活习性,家禽能在开阔的草地上采食和自由活动,可以充分利用各种自然资源,有助于家禽增强体质和抗病力,有利于生产安全、营养、保健的畜产品.笔者基于目前放牧家畜的现状,简单评述了放牧对家畜及畜产品的影响.     

无抗时代畜禽养殖新方案

随着我国畜牧业中饲料禁抗和玉米豆粕减量节粮行动计划的实施,出现了畜禽生长缓慢、生长性能下降、发病率增加、死亡率上升、养殖成本升高等问题。如何破解这些问题,我国畜牧工作者从营养调控及饲养管理等方面进行了一系列研究探讨,精准的饲料营养、完善的饲料替抗方案以及优秀的管理必不可少。本文从国内外畜牧业禁抗现状、饲料禁抗带来的养殖问题,无抗时代畜禽养殖新方案等方面进行简述,以期对禁抗养殖提供指导。     

抗病营养微生态制剂在畜禽养殖上的研究进展

微生态制剂是由活体微生物构成的活性制剂。科学研究表明,它对动物机体具有多种不同的有益特征,如效果好、无残留等,从而成为世界各国学者的研究热点,并且已经开发出了许多不同的产品应用于市场。微生态制剂中不同的益生菌表现出了不同的生物活性,单独或者混合使用都对动物机体在抗病、营养方面发挥着重要的免疫调节、预防疾病的作用。因此,微生态制剂在畜禽养殖上代替抗生素的使用成为必然发展趋势。综述了微生态制剂的定义、起源、发展及近几年在抗病营养方面对畜禽养殖业的影响。     

马驴养殖福利研究进展

动物福利是国内外学者热议的话题,也是标准化生产和畜产品质量安全的重要影响因素.动物福利体现在饲养、养殖环境、健康、行为等各个环节中.马驴作为中国重要的草食家畜,在精准扶贫和乡村振兴中发挥着重要作用.该文阐述了马驴养殖的经济价值,对中国马驴养殖福利现状和动物福利在马驴养殖中的相关影响因素进行探讨,为宣传、提升马驴养殖福利...     

Effects of maternal nutrition and porcine growth hormone (pGH) treatment during gestation on endocrine and metabolic factors in sows, fetuses and pigs, skeletal muscle development, and postnatal growth

Prenatal growth is very complex and a highly integrated process. Both maternal nutrition and the maternal somatotropic axis play a significant role in coordinating nutrient partitioning and utilization between maternal, placental and fetal tissues. Maternal nutrition may alter the nutrient concentrations and in turn the expression of growth regulating factors such as IGFs and IGFBPs in the blood and tissues, while GH acts in parallel via changing IGFs/IGFBPs and nutrient availability. The similarity in the target components implies that maternal nutrition and the somatotropic axis are closely related to each other and may induce similar effects on placental and fetal growth. Severe restriction of nutrients throughout gestation has a permanent negative effect on fetal and postnatal growth, whereas the effects of both temporary restriction and feeding above requirements during gestation seem to be of transitional character. Advantages in fetal growth gained by maternal growth hormone treatment during early to mid-gestation are not maintained to term, whereas treatment during late or greatest part of gestation increases progeny size at birth, which could be of advantage for postnatal growth. This review summarizes the available knowledge on the effects of different maternal feeding strategies and maternal GH administration during pregnancy and their interactions on metabolic and hormonal (especially IGFs/IGFBPs) status in the feto-maternal unit, skeletal muscle development and growth of the offspring in pigs.     

Effects of maternally administered depot ACTH(1-24) on fetal maturation and the timing of parturition in the mare

The aims of this study were to ascertain 1) whether fetal maturation could be induced precociously by maternal administration with adrenocorticotrophic hormone (ACTH) and 2) whether maturation could be achieved without significant risk to mare or fetus. Twenty-two mares received either 1 mg (low dose, LD, n = 6) or 4 or 5 mg (higher dose, HD, n = 16) synthetic Depot ACTH(1-24) at 300, 301 and 302 days gestation. Because, during the course of the study, ACTH appeared to have a greater influence on mares mated during the later part of the breeding season, the HD group were divided retrospectively into those mated before (HDE, n = 6), or after (HDL, n = 10), 1st July. All LD mares were mated before 1st July. Control injections were not performed but gestational data were compared retrospectively with 64 untreated, spontaneously foaling pony mares mated between May and October. Plasma progestagen and cortisol concentrations increased significantly (P<0.05) following ACTH administration in all groups, but progestagens were higher and cortisol elevated for longer in HD mares. ACTH stimulated mammary development and milk electrolyte changes in HD mares. Mean +/- s.e. gestation period (days) was significantly (P<0.01) shorter in HDL mares (318 +/- 1.8) compared with LD (335 +/- 3.7), HDE (340 +/- 4.3) and untreated mares mated after 1st July (327 +/- 1.3). All foals were mature except 2 HDL foals which were stillborn. HDL foals had a higher MCV and lower mean bodyweight, indicating they were delivered before full term. In conclusion, maternal ACTH administration appears to accelerate fetal maturation and delivery in pony mares given high doses and mated late in the breeding season. Further work is required to establish the optimal gestational age and dosage for maternal ACTH administration before clinical recommendations can be given for this therapy.