猪采食量的调控

动物采食量是限制动物生产性能及基因潜力发挥的最主要因素之一，提高动物采食量已逐渐成为动物营养生理研究的一大热点。文章主要对猪的采食量的重要性，采食量的调节机制、影响采食量的因素及调控采食量的因子进行综述。     

动物采食量与粪便量的微控技术

采食量是影响动物生产性能的决定性因素，也是提高动物生产效率的关键。文章阐述了猪采食量的反馈调节、猪的采食能力、影响动物采食量的短期调控因素和长期调控因素，指导在实际生产中如何提高猪的采食量，减少粪便量，提高生产性能。     

猪采食量的调控

动物采食量是限制动物生产性能及基因潜力发挥的最主要因素之一,提高动物采食量已逐渐成为动物营养生理研究的一大热点.文章主要对猪的采食量的重要性、采食量的调节机制、影响采食量的因素及调控采食量的因子进行综述.     

影响猪采食量的因素及对策

正猪的采食量影响猪的正常生长发育和生产性能,了解影响猪采食量的因素有助于对采食量进行调控,提高猪的生产性能,降低饲养成本。本文对影响猪采食量的因素进行了详细分析并提出了相应的对策,以供养殖户参考。1影响猪采食量的因素影响猪采食量的因素有很多,主要有动物自身的因素、饲料、饲喂技术、环境因素等。1.1动物自身的因素1.1.1遗传因素采食量的遗传性很低,但是和生长速度、瘦肉率的相关性比较大,经常选择提高生长速度和瘦肉率的     

猪采食调控机制研究进展

猪的采食量与其生长速度、生产性能息息相关。在保证猪健康生长的同时,尽可能地提高其采食量,是提高养猪生产效益的重要途径。猪的食欲和采食行为受到外界环境、饲养技术、自身物理特性、体内化学和代谢因子、中枢和外周信号因子的综合调控。下丘脑在整合各种信号从而发挥采食调控作用的网络中发挥着关键作用。分子生物学手段的应用使得采食信号因子的研究不断取得突破,NPY、CCK、SS、Orexin、Ghrelin等在下丘脑采食调控网络中的作用和信号途径已日渐明朗,而AMPK、mTOR和Leptin更是成为近年来的研究热点。作者从影响猪采食行为的因素、下丘脑的调控作用及影响采食行为的主效因子等方面展开论述,综述了当前国内外在猪采食调控方面的研究进展,针对存在的问题提出讨论,并对接下来的研究方向做出展望。     

温热环境因子影响肉鸡采食的调控机制

采食量是影响肉鸡健康生长的重要因素,摄入的营养物质除一部分用于维持肉鸡基本生命代谢需求外,大部分用于保障肉鸡良好的生长性能。下丘脑作为中枢神经系统调节采食量的重要部位,它可以整合外周环境和各种信号分子,使得机体做出适当的反应,最终调节肉鸡的采食量。温热环境因子是实际生产中影响家禽采食行为和生长性能的重要环境因素,本文就温热环境因子对肉鸡采食行为的影响、下丘脑的摄食信号整合机制以及关键热信号分子的调控机制作一综述,以期为肉鸡温热环境控制提供理论依据。     

免疫调控技术在畜禽采食量调控中的应用

采食量是限制动物生产性能及遗传潜力发挥的最重要因素之一,但采食量的调节是一个涉及中枢和外周食欲调节网络中诸多环节因素的复杂生理过程,其中负反馈饱食因子在确保机体摄食及代谢平衡方面发挥着重要的作用。免疫调控技术是一种新兴的生物调控技术,利用抗原抗体免疫中和原理削弱或消除抑食信号的作用,同时通过这种免疫介导手段又不会产生像脂多糖或其他病原因素导致的免疫应激,从而实现对畜禽采食量的有效调控。本文主要综述了免疫调控技术在畜禽采食量方面的应用,以期为免疫调控技术在畜禽采食量上的进一步研究提供参考。     

促进猪采食量提高的意义和措施

正猪的采食量决定猪生产性能高低和养殖效益好坏,提高猪的采食量意义重大。影响采食量的因素有遗传、环境、饲养管理方式、饲料品质、饮水质量和健康状态等。在猪生产中,可以针对这些影响猪采食量的因素采取综合措施提高采食量。1提高猪采食量的意义猪作为经济动物,人类饲养它是为了充分发挥并利用其生产性能(经济性状),从而获取最大化效益。采食量直接决定着生猪能够从外界环境中获得营     

高温对猪采食量的影响机制及应用的研究进展

采食量是保证猪生产性能充分发挥的关键因素。温度对猪的采食量影响较大。温热恒定机制是调节猪采食量的主要方式,环境温度通过改变猪与环境的热交换而影响其采食量,且影响最为明显。作者阐述了温度对猪采食量的调节机制、温度对采食量的影响等研究进展。     

中枢神经系统整合外周信号调节采食量的分子机制

采食量是动物生产性能充分发挥的基石,其受多种因素的共同调节。胃肠调节肽、肥胖信号分子(瘦素和胰岛素)及营养物质等外周调节因子在采食量的调节中发挥重要的作用。中枢神经系统是采食量调节的关键。近年来对中枢神经系统调节采食量的分子机制认识越来越深入,已鉴定出一些关键信号转导通路及转录因子,其中哺乳动物下丘脑雷帕霉素靶蛋白(mTOR)通路、一般性调控阻遏蛋白激酶2(GCN2)介导的一般性氨基酸应答通路及叉头转录因子1(FoxO1)和信号转导与转录激活因子3(STAT3)在中枢的采食量调节中起着重要作用。本文在简要回顾采食量调节生理机制的基础上,主要对外周信号在中枢神经系统调节采食量分子机制的研究进展进行综述。     

Efficacy of sucrose and milk chocolate product or dried porcine solubles to increase feed intake and improve performance of lactating sows

Two experiments were conducted to determine the voluntary feed intake and performance of lactating sows fed diets containing a sucrose/milk chocolate product (MCP) blend (Exp. 1) or dried porcine solubles (DPS; Exp. 2). Dried porcine solubles is a coproduct of heparin extraction from porcine small intestines. In Exp. 1, mixed-parity sows (n = 108) at two research centers were assigned to a corn-soybean-meal-based diet formulated to contain 0.9% total lysine or a similar diet that contained 4% sucrose and 2% MCP on an as-fed basis. Sows were allowed ad libitum access to dietary treatments from the day of farrowing until pigs were weaned at approximately 21 d postpartum. Diet had no significant effect on voluntary feed intake of sows during lactation, backfat depth, or postweaning interval to estrus, but it had variable effects on body weight changes. Inclusion of the sucrose/MCP blend in diets elicited a 2% improvement in litter weaning weight at one research center and a 6% depression in litter weaning weight at the other center (diet x research center, P < 0.05). Litter size throughout lactation was unaffected by dietary treatment. In Exp. 2, mixed-parity sows (n = 119) at two research centers were assigned to corn-soybean meal-based diets formulated to contain 0.9% total lysine with 0, 1.5, or 3.0% added DPS. Sows were assigned to dietary treatments within research center, farrowing group, and parity at parturition. Dried porcine solubles tended to increase (P < 0.10) total feed consumed in the first 9 d of lactation and average daily feed intake over the entire lactation (6.03, 6.53, and 6.30 kg) for sows fed 0, 1.5, and 3.0% DPS, respectively. Litter size and weight on d 18 of lactation were not affected by concentration of DPS in the diet. Days from weaning to estrus and percentage of sows displaying estrus were not influenced by diet. We conclude that inclusion of the sucrose/MCP blend in the diet for lactating sows had no consistent effect on voluntary feed intake of sows and weight gain of nursing pigs. Inclusion of DPS at 1.5 or 3.0% tended to improve feed intake of lactating sows but had no significant influence on litter performance.     

Genetic associations between observed feed intake measurements during growth,feed intake curve parameters and growing–finishing performances of central tested boars

Optimization of growing–finishing performance can be reached by increasing feed intake capacity of pigs at an early stage of growth and by limiting feed intake at the end of the finishing period. Daily feed intake recorded by electronic feeder and other growth performances were obtained from 5601 group-penned nucleus boars of two dam lines on a central test station. A multiple trait animal model was used which considers the observed feed intake at each test week as a different trait. Estimated heritabilities for feed intake were 0.12, 0.23, 0.29, 0.39, 0.32 and 0.39 for the first, third, fifth, seventh, and ninth test week, and entire test period, respectively. A linear regression and a linear-quadratic regression were fitted for daily feed intake as functions of time. Heritabilities of the function parameters ranged between 0.11 and 0.32. Average estimated feed intake and average change in daily feed intake (slope) were obtained for five periods (12 days) based on linear-quadratic regression. Heritabilities for average estimated feed intake changed from 0.17, 0.32, 0.37, 0.43 to 0.41 and the slope of feed intake from 0.18, 0.21, 0.33, 0.27 to 0.22 with time on test. Genetic correlations of observed feed intake among different periods were substantially different from one (0.02–0.73) which indicates that feed intake was differently genetically determined during growth. In order to account for the different genetic relationships of feed intake during performance test and their influence on other performance traits, a multiple trait animal model using average estimated feed intake of each period, slope of the first three periods, and all genetic associations among these traits, were recommended to improve feed efficiency and lean growth.     

猪肌内脂肪沉积的营养调控及候选基因的研究进展

营养调控和基因调控方法相结合是改善猪肌内脂肪沉积的根本途径,已经发现多种不同的营养素(如能量蛋白水平、甜菜碱、矿物质、维生素、共轭亚油酸等)对猪肌内脂肪沉积有重要的调控作用,但目前影响猪肌内脂肪沉积的主效基因并未确定。本文主要综述了不同营养素对猪肌内脂肪沉积的调控作用以及主要的候选基因对猪肌内脂肪沉积作用的研究进展。     

氟烷基因对猪生产经济性状的影响

猪应激综合征(Porcine Stress Syndrome,PSS)是受猪染色体上的隐性基因-氟烷基因控制,使得猪只在受到外界环境的刺激时,临床上出现发抖、呼吸急促、呼吸困难、皮肤变紫色、体温上升、肌肉硬化甚至死亡等一系列症状,外界压迫因素越大,对猪只造成的影响越强烈。文中综述氟烷基因对猪生长性能、繁殖性能以及猪肉品质的影响,以期为猪养殖者及实验室检测方面提供参考。     

Direct and maternal genetic parameters for measures of feed consumption and feed efficiency in young male Japanese Black cattle

Direct and maternal genetic parameters for measures of feed consumption and feed efficiency were estimated using data recorded on 514 performance tested young male Japanese Black cattle during the period from 1978–2004. Measures of feed consumption were daily feed intake, concentrate intake, ratio of roughage intake to feed intake, total digestible nutrient intake, digestible crude protein intake (DCPI) and metabolizable energy intake. Feed efficiency traits included feed conversion ratio (FCR), total digestible nutrient conversion ratio (TCR), digestible crude protein conversion ratio (DCR) and residual feed intake. Data were analyzed using three alternative animal models (including direct and direct plus maternal genetic effects (including or excluding covariance between direct and maternal genetic effects)). The direct heritability estimates for all the measures of feed consumption and feed efficiency were moderate to high, suggesting that sufficient genetic variation exists in these traits which should respond to selection. All the measures of feed consumption were genetically more strongly correlated with residual feed intake than with other measures of feed efficiency. Maternal heritability estimates for DCPI, FCR and TCR were not significantly different from zero, while the corresponding estimates for all the studied traits were low (ranged from 0.07 to 0.24). The estimates of direct heritability for measures of feed consumption were reduced up to 34% when maternal genetic effect was considered in the model. An antagonistic relationship existed between direct and maternal genetic effect (r_am) for FCR and DCR, which biased the estimates of direct heritability downwards. The results indicate that maternal effects play an important role in measures of feed consumption and most of the feed efficiency traits, which should be accounted for these traits in genetic evaluation system.     

禽类采食量生理调节因子的研究进展

采食量是影响禽类生长最重要的因素之一。认识采食量的调节规律和机制,旨在更有效地调节家禽的采食量,为生产实践提供重要指导。禽类采食量的生理调节机制十分复杂,涉及许多神经通路和体液因子的调节。本文将重点介绍采食量生理调节因子。     

Genetic and phenotypic variance and covariance components for feed intake, feed efficiency, and other postweaning traits in Angus cattle.

Records on 1,180 young Angus bulls and heifers involved in performance tests were used to estimate genetic and phenotypic parameters for feed intake, feed efficiency, and other postweaning traits. The mean age was 268 d at the start of the performance test, which comprised 21-d adjustment and 70-d test periods. Traits studied included 200-d weight, 400-d weight, scrotal circumference, ultrasonic measurements of rib and rump fat depths and longissimus muscle area, ADG, metabolic weight, daily feed intake, feed conversion ratio, and residual feed intake. For all traits except the last five, additional data from the Angus Society ofAustralia pedigree and performance database were included, which increased the number of animals to 27,229. Genetic (co)variances were estimated by REML using animal models. Direct heritability estimates for 200-d weight, 400-d weight, rib fat depth, ADG, feed conversion,and residual feed intake were 0.17 +/- 0.03, 0.27 +/- 0.03, 0.35 +/- 0.04, 0.28 +/- 0.04, 0.29 +/- 0.04, and 0.39 +/- 0.03, respectively. Feed conversion ratio was genetically (r(g) = 0.66 ) and phenotypically (r(p) = 0.53) correlated with residual feed intake. Feed conversion ratio was correlated (r(g) = -0.62, r(p) = -0.74) with ADG, whereas residual feed intake was not (rg = -0.04, r(p) = -0.06). Genetically, both residual feed intake and feed conversion ratio were negatively correlated with direct effects of 200-d weight (r(g) = -0.45 and -0.21) and 400-d weight (r(g) = -0.26 and -0.09). The correlations between the remaining traits and the feed efficiency traits were near zero, except between feed intake and feed conversion ratio (r(g) = 0.31, r(p) = 0.23), feed intake and residual feed intake (r(g) = 0.69, r(p) = 0.72), and rib fat depth and residual feed intake (r(g) = 0.17, r(p) = 0.14). These results indicate that genetic improvement in feed efficiency can be achieved through selection and, in general, correlated responses in growth and the other postweaning traits will be minimal.     

猪繁殖与呼吸综合征病毒分子生物学研究进展

猪繁殖与呼吸综合征病毒(PRRSV)是引起猪繁殖与呼吸综合征的病原体,本文对PRRSV的分子生物学研究进展进行了综述,主要包括PRRSV的基因组结构、病毒蛋白及其功能、抗原变异等,旨在为诊断技术、免疫机理研究、疫苗设计与疫病防制提供借鉴.