动物补偿生长效应研究进展

本文就补偿生长的概念、分类、作用机理及其对动物的影响等进行论述。     

动物补偿生长研究进展

补偿生长技术广泛应用于草食动物、家禽和猪等动物的特定饲养阶段,可提高机体蛋白质沉积率、改善饲料利用率、促进激素分泌、增强酶活性等。本文就补偿生长对动物机体的影响及其限制因素进行阐述,并浅谈补偿生长在动物生产上的应用现状及前景。     

绵羊补偿生长的利用研究

补偿生长是动物的一种生长发育生理规律，指动物在生长发育的某一阶段，因饲料缺乏或不足遭受营养限制，适应了较低的营养水平，活重上表现为增重负值、缓慢或不能达到遗传上的生长潜力，而一旦营养恢复，动物的生长则表现出加速，以弥补在营养受限制期间减少的增重。目前，我国的肉羊生产无论在草原区、     

共轭亚油酸对猪胴体品质调控的应用研究进展

随着人们生活水平的改善，人类对畜产品的品质要求愈来愈高，如何降低其体脂沉积，增加蛋白质积累，改善肉品质，一直是困扰畜牧业的难题。为了降低生产成本并满足消费者对低脂肪的要求，人们一直在寻找降低肉品脂肪含量的方法。近几年的研究表明，在日粮中添加共轭亚油酸能够增强动物免疫力，提高饲料利用效率，增加瘦肉率等作用，     

动物脂肪代谢及其调控的研究进展

脂肪的沉积是动物机体能量沉积的一种主要方式，其体脂沉积量实际体现了脂肪合成代谢和分解代谢的一种平衡状态。当合成代谢与分解代谢之间的平衡被打破，如合成代谢增强或分解代谢减弱。机体脂肪沉积量都会增加。甚至导致过度肥胖。而随着人们生活水平的提高，消费者在得到膳食满足的同时。对畜产品品质也日益重视。脂肪的过度沉积不仅影响畜产品的品质，造成能量的浪费，而且对环境保护也不利。多年来。国内外学者围绕猪的脂肪沉积及其调控机理做了大量研究。以其能够人为的控制脂肪代谢，不仅提高生产水平，创造最佳效益，而且还能满足现代人们的消费需要，提高人类自身健康水平。本文就近年来国内外围绕脂肪沉积的机理及其调控方面的进展作一综述。     

苯甲醇胺盐对肉猪生长及胴体品质效应的研究

苯甲醇胺盐(Clenbuterol,又称克喘素、双氯醇胺)系非营养性饲料添加剂,最早用于治疗人和动物的某些疾病,80年代初,美国Cyanamid公司研究部首先发现此药可使肉用动物多长瘦肉少沉积脂肪。为了探明不同处理方法和不同剂量的苯甲醇胺盐对猪的作用效果,我们进行了本试验,目的在于为苯     

营养水平对商品猪生长性能、肉质影响研究

试验选择体重35kg左右的杜莱断奶仔猪48头，随机分为3组，采食3种营养水平的日粮，研究日粮营养水平对试验猪的生长性能及肉品质影响。结果表明：营养水平对试验猪的日增重、饲料报酬和肉质无明显影响，对屠宰率、眼肌面积和瘦肉率影响显著。利用综合选择指数对各营养水平的影响进行综合评定，在35～90kg体重阶段低营养水平（配方3）对杂交商品猪的作用效果最好。     

霉菌和霉菌毒素对饲料品质和动物生长的影响

霉菌（Mold）是真菌（Fungi）的一部分,一般认为凡是在基质上长成绒毛状、棉絮状或蜘蛛状的菌丝体真菌都可称为霉菌。霉菌在自然界分布广泛,饲料原料在生长、收割、加工、储藏和运输过程中,均会受到不同程度的霉菌污染,特别是饲料原料在加工过程中必需粉碎,暴露出的营养物质极易被霉菌污染。我国南方地处亚热带地区,每年从3、4月份到8、9月份,气温高（一般在20℃以上）,相对湿度大（一般在80％以上）,且潮湿多雨,     

天然复合矿物对肉猪生长性能,胴体品质影响的试验研究

９２头仔猪，分两批（每批４组）作基础日粮添加不同配方（Ａ、Ｂ、Ｃ）天然坚合矿物粉试验。结果表明，添加天然复合矿物粉对肉猪的生长性能及胴体品质均有一定的促进作用。其中以Ｂ方较稳定，日增重平均提高８．４％，料肉比下降９．２％，胴体瘦肉率提高５．０２百分点     

甲壳素在动物生长过程中的调节作用

甲壳素又称甲壳质 ,是 1,4 -连接的 2 -乙酰氨基 - 2 -脱氧 - β -D -葡萄糖 ,广泛存在于昆虫、甲壳纲动物外壳及真菌的细胞壁中 ,是自然界中产量仅次于纤维素的天然多糖。它具有很多形式的衍生产物 ,甲壳素在水及有机溶剂中不溶 ,壳聚糖只在稀酸中溶解 ,所以其应用范围受到了限制。在甲壳素的分子结构中除了含有羟基外 ,还含有活泼的氨基 ,易于化学改性引入多功能基团 ,拓宽应用领域。特别是对其生物活性及在药物制剂、医学高分子材料等的医学应用研究十分活跃。这类多糖既可生物合成 ,又可生物降解 ,降解过程中产生的低分子寡聚糖在体内…     

牛羊补偿生长的研究进展

综合了当今世界对草食家畜补偿生长的研究,探讨了影响补偿生长的主要因素是年龄、基因类型、营养限制的程度和持续时间、补充营养物质的质量和持续时间.补偿生长的作用机制是通过营养限制减少维持需要、增加采食量、增加生长效率和增加消化道内容物来实现的,特别在目前有关补偿生长的研究中,激素是热点话题,不同激素的作用可以看作是补偿反应的一个完整组成部分.     

异针茅在不同生境下补偿生长特性及其影响因素的研究

植物的补偿生长受放牧扰动和生境资源的共同影响,但何种条件易于引起植物发生超补偿生长是长期以来争论的问题。在矮嵩草（Kobresia humilis）草甸3种生境（畜圈、牧道、封育）设置扣笼和无扣笼对比样方（不放牧和放牧处理）研究了异针茅（Stipa aliena）的补偿生长特性。结果显示,异针茅分株各部分中除根系在牧道生境为等量补偿外,叶片和花序在畜圈和牧道生境均为低补偿。异针茅的分株密度、高度以及生长分配在封育生境最高。分株各部分的相对生长率在畜圈生境最低,在牧道生境最高。典范对应分析表明,对异针茅补偿生长和相对生长率影响最大的因子是采食率。尽管畜圈生境具有良好的土壤养分和水分条件,但仍不能抵消该生境家畜重度采食和践踏对异针茅的负面影响。研究结果表明,影响异针茅分株种群补偿生长的主要因素是放牧强度,而土壤资源获得性的影响相对较小。     

蛋氨酸对动物生长发育及毛发生长调控作用的研究进展

蛋氨酸(Met)是动物生长必需氨基酸中唯一含硫氨基酸,其可参与机体内众多代谢途径,为动物提供甲基,合成动物生长所需要的蛋白质和生物活性物质,是动物生长和毛发生长的第一限制性氨基酸。日粮中必须添加适量的蛋氨酸才能满足动物生长需要,对毛皮动物,蛋氨酸还会影响毛发的生长和品质,所以蛋氨酸又被称为"生命性氨基酸"。本文综述了蛋氨酸在动物生长发育及毛发生长中的调控作用,以期为蛋氨酸在畜牧生产中的科学应用提供参考。     

Mechanisms of reduced and compensatory growth

Growth is an integrated process, resulting from the response of cells dependent on the endocrine status and nutrient availability. During feed restriction, the production and secretion of growth hormone (GH) by the pituitary gland are enhanced, but the number of GH receptors decreases. Changes of GH binding proteins induce GH resistance and are followed by reduced insulin-like growth factor-I (IGF-I) secretion. On the other hand, high circulating levels of GH enhance the mobilization of fatty acids, which are used to support energy requirements. Thus, when feed restriction in growing animals is moderate, there is mainly protein but barely fat accretion. By contrast, a severe feed restriction enhances the release of catabolic hormones and stimulates, from muscle cells, the liberation of amino acids, which are used by hepatocytes for gluconeogenesis. During refeeding and compensatory growth, the secretion of insulin is sharply enhanced and plasma GH concentrations remain high. This situation probably allows more nutrients to be used for growth processes. The role of plasma IGF-I during compensatory growth is not clear and must be explained in connection with changes of its binding proteins. Thyroxin and 3,5,3'-triiodothyronine seem to have a permissive effect on growth. The simultaneous occurrence of puberty with refeeding can exert a synergistic effect on growth. Initially, compensatory growth is characterized by the deposition of very lean tissue, similar as during feed restriction. This lasts for some weeks. Then, protein synthesis decreases and high feed intake leads to increased fat deposition.     

Effects of growth rate and compensatory growth on body composition in lambs

Fifty lambs were used in a comparative slaughter experiment to determine the effects of growth rates and compensatory growth on body composition. The study consisted of a growing and a finishing phase. During the growing phase, lambs (20 to 30 kg) were fed three different concentrate levels (30, 50 or 70%) to gain at three different rates (slow, medium and rapid). The finishing phase was evaluated in two periods (early, 30 to 38 kg; late, 38 to 45 kg). All lambs received 70% concentrate diets during the finishing phase. Groups of five lambs were sacrificed at 20, 30, 38 and 45 kg fleece-free weights for whole-body chemical analysis. At 30 kg live weight, lambs on a rapid growth diet were the fattest (P less than .01) and contained the least protein (P less than .05) in their empty bodies. The slower the lambs gained during the growing phase, the greater (P less than .05) was the response in rate of gain and feed efficiency during both periods of the finishing phase. Compensatory growth occurred in two stages; a greater proportion of protein gain was made early while a greater proportion of the fat gain was made during the late period of the finishing phase.     

植物补偿性生长与草地可持续利用研究

1998～1999年,对不同放牧强度下内蒙古大针茅草原植物的利用率和净初级生长量的研究结果表明绵羊对草群和大针茅的采食率与牧草的叶龄结构和生长速率密切相关;在降雨量充沛的情况下,随着牧草采食率的提高,草群和大针茅净初级生长量呈现单峰型增长动态,草群和大针茅的高峰值分别出现在45%～55%和55%～60%的采食率范围,并且分别在30%～55%和35%～65%的采食率范围内表现出超补偿生长,超出此范围则表现欠补偿生长;依据草群和大针茅补偿生长规律,大针茅草原适宜采食率在45%～55%之间,相应载畜率为3.5只羊/夏、秋季/hm2.在此采食率范围内,草地可以获得长久的超补偿或等补偿生长,草地的生产能力增加,草地植物组成维持相对稳定,可保证草地的持续利用.     

放牧条件下苏尼特母羊补偿生长的研究

将妊娠后期（90-150d)(限制饲养期间）处于四个不同营养水平组（每日0.2,0.33,0.44,0.86MJ/W^0.75)的27只母羊在分娩后（0-26周）分为八组。试验羊在0-6周自由采食饲草；6-16周在放牧的基础上Ⅰ，Ⅲ，Ⅳ，Ⅶ组补饲草及料，Ⅱ，Ⅳ，Ⅵ，Ⅷ组补草；在16-26周各组羊放牧采食。目的在于研究苏尼特母羊的补偿生长能力。研究表明，在营养限制期间营养限制程度越严重母羊分娩后采食高质量饲粮其补偿生长持续的时间越长，如本试验Ⅰ组，Ⅰ，Ⅲ，Ⅴ，Ⅶ组在6-16周补饲精料期间其生长速率较快，在16-26周放牧采食高质量牧草期间其生长速率较慢。这表明其生长潜力在6-16周已得到良分的挖掘：Ⅱ,Ⅳ，Ⅵ，Ⅷ组在6-16周尽管补饲饲草，但其生长速率较低。而在16-26周放牧采食高质量牧草时其生长潜力却得到充分的发挥，这表明苏尼特羊对低营养有很强的适应能力。在26周时各组的体重无差异。这表明妊娠后期限制饲养导致的各组母羊分娩后的体重差异。在羔羊自然断奶后在恢复营养后第26周时得到“完全补偿”；同时表明，在6-16周补饲精料是不必要的。     

Muscle protein degradation in bull calves with compensatory growth

Twelve 5-month-old bull calves were allocated to two feeding strategies: AA, 6 calves were fed ad libitum 34 weeks; and RA, 6 calves were fed restrictively for 14 weeks with an intake of 50% of the metabolic energy and protein eaten by the AA calves, followed by ad libitum feeding for 20 weeks. At the end of the 14-week restriction period, and after 2, 5, 8, 11, 14 and 17 weeks of re-alimentation, urine, blood and muscle biopsy samples from M. longissimus dorsi (LD) were collected. The urine was analysed for 3-methylhistidine for determination of the fractional breakdown rate of muscle protein (FBR). The FBR was depressed during restricted feeding (1.4 versus 2.0%/day; P = 0.05), however, during re-alimentation where the calves exerted compensatory growth, the FBR increased and reached a maximum after 5 weeks into this period (3.1 versus 1.9%/day; P < 0.001). The maximal FBR in the RA calves coincided with a maximum concentration of RNA and DNA in LD, and a maximal fractional rate of growth. The activity of μ-calpain in LD and the concentration of IGF-I in serum were decreased at the end of the restriction period but increased as soon as energy was offered ad libitum. The results support the hypothesis that muscle protein turnover is affected by a restriction/re-alimentation feeding strategy, and that muscle protein degradation reaches a maximum during the re-alimentation period, which exceeds that of control animals.     

动物布鲁氏菌病的研究进展

布鲁氏菌病(Brucellosis)也称作“马尔他热”、 “地中 海热”或“波状热”,是由布鲁氏菌引起的一种人兽共患 的传染病,严重危害人类健康和畜牧业发展。