基因组，基因表达与饲料

生物体生长发育过程中的一个基本行为就是定位于基因组中的基因系统的活动。因而,生物发育中不断的进行着具有时间和器官特异性的基因表达或抑制,这些过程最终引起特定蛋白的合成。来自基因组外或外界的环境信号会使这种特异性基因表达模式发生变化,从而产生多重效果,比如生长、分化、健康的维持、疾病的避免或发作以及生长抑制等。经过进化,人们已经意识到许多具有生物活性的日粮成分（即营养调节剂）可以控制基因组的表达。日粮中包含一系列重要的信号物质,这些物质可以使多细胞有机体调整其对复杂的环境变化的响应,进而影响到生长发育。     

微量元素与基因表达

动物的生长发育，都是基因表达的结果。大量研究表明：日粮中的微量元素对许多基因的表达均有影响。本从分子生物学的角度阐述了微量元素对基因表达的调控方式及其调控。     

基因表达系列分析技术及其应用领域

基因表达系列分析(serial analysis gene express，SAGE)是近几年发展起来的一种快速分析基因表达信息的技术。它通过快速而详细地分析成千上万个EST(expressed sequencedtags)来寻找出表达丰度不同的SAGE标签序列，从而接近完整地获得基因组表达信息。它不但能快速、详细地同时分析成千上万个基因转录子的丰富信息，还能发现新基因，因此是基因表达定性和定量研究的一种有效工具，     

天然矿物饲料添加剂

8．动物肌体由矿物元素间的相互关系。动物机体是由各种物质元素组成。组成动物机体的元素，除与生命活动相关以外，还必需与外界地球环境中元素和在机体内元素间保持统一平衡，以维持动物生命和生产。动物在自然状态下，这种平衡主要是靠自然选择和自然规律来进行调节。而在人类控制饲养的条件下，尤在集约化饲养下，按人的意志进行动物生产下，其统一平衡就要靠人用饲料的元素组合来进行调控。     

饲料中共轭亚油酸的功能及其对动物基因表达的影响

亚油酸（Linoleic Acid,LA）是人和动物的必需脂肪酸之一,体内无法合成,必需从食物中摄取。共轭亚油酸（Conjugated Linoleic Acid,CLA）是由亚油酸衍生的一组亚油酸异构体,是普遍存在于人和动物体内的营养物质。     

饲料添加剂与动物食品安全

饲料添加剂因其对动物生长发育和防病治病等方面的显著作用被广泛地应用到畜禽养殖业中。饲料添加剂在提高动物产品数量和质量的同时,因其在产品中的残留而带来的食品安全问题也越来越受到人们的重视。因此如何在保证食品安全的前提下,合理使用饲料添加剂受到了社会的普遍关注。     

人工饲料育和桑叶育家蚕消化酶基因表达差异研究

α-淀粉酶、麦芽糖酶、脂肪酶和类胰蛋白酶与家蚕中肠对营养物质的消化密切相关。运用荧光定量PCR技术,对人工饲料育与桑叶育家蚕中肠中这4种消化酶基因在4、5龄期的表达情况进行了测试。结果表明,人工饲料育与桑叶育家蚕中4种消化酶的表达均存在较大差异,特别是人工饲料育家蚕5龄期的脂肪酶和类胰蛋白酶基因的表达量极显著低于桑叶育家蚕中的表达量,这可能影响到家蚕对营养物质的消化吸收、生长发育和抗病性。     

新饲料、新饲料添加剂展示

<正>乳酸锌属于有机锌制剂,作为饲养动物必需微量元素锌的补充剂,可广泛应用于畜禽动物配合饲料、浓缩饲料和预混合饲料中。主要特点是:1化学性质稳定,在180℃表现出良好的热稳性,能够耐受饲     

新饲料和新饲料添加剂管理办法

第一条 为加强新饲料、新饲料添加剂管理,保障养殖动物产品质量安全,根据《饲料和饲料添加剂管理条例》,制定本办法。第二条本办法所称新饲料,是指我国境内新研制开发的尚未批准使用的单一饲料。本办法所称新饲料添加剂,是指我国境内新研制开发的尚未批准使用的饲料添加剂。第三条有下列情形之一的,     

新饲料、新饲料添加剂展播

<正>(接上期)杜仲叶提取物商品名称:杜仲素产品特点:1天然植物提取物,不含任何化学合成类物质;2有效成分明确,功能确定,活性成分能够量化控制;3提高动物增重和饲料转化效率;4有效改善动物产品的肉     

Circulating leptin and its muscle gene expression in Nellore cattle with divergent feed efficiency

Background: Leptin has a strong relation to important traits in animal production, such as carcass composition,feed intake, and reproduction. It is mainly produced by adipose cells and acts predominantly in the hypothalamus.In this study, circulating leptin and its gene expression in muscle were evaluated in two groups of young Nellore bulls with divergent feed efficiency. Individual dry matter intake(DMI) and average daily gain(ADG) of 98 Nellore bulls were evaluated in feedlot for 70 d to determinate the residual feed intake(RFI) and select 20 animals for the high feed efficient(LRFI) and 20 for the low feed efficient(HRFI) groups. Blood samples were collected on d 56 and at slaughter(80 d) to determine circulating plasma leptin. Samples of Longissimus dorsi were taken at slaughter for leptin gene expression levels.Results: DMI and RFI were different between groups and LRFI animals showed less back fat and rump fat thickness,as well as less pelvic and kidney fat weight. Circulating leptin increased over time in all animals. Plasma leptin was greater in LRFI on 56 d and at slaughter(P = 0.0049). Gene expression of leptin were greater in LRFI animals(P = 0.0022) in accordance with the plasma levels. The animals of the LRFI group were leaner, ate less, and had more circulating leptin and its gene expression.Conclusion: These findings demonstrated that leptin plays its physiological role in young Nellore bulls, probably controlling food intake because feed efficient animals have more leptin and lower residual feed intake.     

Effects of breed and harvest age on feed intake, growth, carcass traits, blood metabolites, and lipogenic gene expression in Boer and Kiko goats

The objectives of this experiment were to determine the effects of 2 different breeds (BR), Boer and Kiko, and 4 post-weaning harvest ages (HA; Days 0, 29, 56, and 85) on growth, carcass traits, blood metabolites, and lipogenic gene expression. Forty-eight goat (Capra hircus) kids (BW = 23.9 ± 1.50 kg; 3 to 4 mo) were used in a 2 × 4 factorial arrangement of treatments. Goats were stratified by BW within BR and randomly assigned to 4 HA. Kids were born between March 15 and April 7 to purebred does, and were represented by at least 3 purebred sires within each BR. They were fed a grain/hay (80:20) diet once per day. At designated HA, randomly pre-assigned goats (n = 6) from each BR were transported to the Meat Science Lab at Mississippi State University, Starkville, MS, and were harvested. There were no interactions (P > 0.10) between BR and HA. Boer tended (P = 0.08) to have greater initial BW, final BW (P = 0.05), and G/F ratio (P = 0.05). Although the 80:20 grain/hay diet was reinforced by adjusting DMI, both BR had similar total DMI, Boer kept that ratio, while Kiko consumed more (P = 0.001) hay (70:30, grain/hay) and had more (P = 0.001) DMI when expressed as g/kg BW. Boer tended to have greater transportation shrink (P = 0.07), HCW (P = 0.08), and cold carcass weights (CCW; P = 0.08), with greater (P = 0.001) carcass fat. No differences (P > 0.10) were observed in carcass shrink, dressing percentage, 12th rib fat thickness, and LM area between the 2 BR. When expressed as percentage empty BW, carcass bone was similar (P = 0.25), whereas muscle percentage (P = 0.02) was greater for Kiko and fat percentage was greater (P = 0.001) for Boer. Fat as a percentage of CCW remained relatively similar (P > 0.10) for both BR for the 2nd and 3rd HA. Differences were more evident (P = 0.01) at the 4th HA. Boer reached targeted harvest weight (29 kg) at the 3rd HA, while fat deposition continued (P = 0.01) during the 4th HA. Breed had no effect (P > 0.10) on meat color (L*, a*, b*) but HA affected (P = 0.001) all color values. Boer had similar 3-hydroxyl-3-methylglutaryl-CoA synthase mRNA abundance, but was greater (P < 0.03) in acetyl CoA carboxylase compared with Kiko. There was no difference (P = 0.52) in total serum fatty acids (FA, mg/mL) between the 2 BR. As animals aged, their total serum FA increased (P < 0.05) and changed to an undesirable profile. Kiko had a greater (P = 0.02) percentage of muscle and less (P = 0.001) fat in the carcass. We concluded that different BR might need different harvest endpoints and feed input according to consumer acceptability.     

Influence of reduced feed ration on Lepeophtheirus salmonis infestation and inflammatory gene expression in juvenile pink salmon

The effect of reduced feed ration on infestation levels with the sea louse Lepeophtheirus salmonis and gene expression in juvenile pink salmon Oncorhynchus gorbuscha was tested in three laboratory trials. Body weight was significantly lower among fish on the reduced ration for 27, 34, or 65 d than fish on the full ration. Neither the prevalence nor the abundance of L. salmonis differed between fish on full and reduced rations at any time in any trial. In trial 2, sea louse rejection was delayed among fish on reduced rations; however, the parasite was ultimately rejected from all fish in this trial regardless of ration. Proinflammatory gene expression in salmon exposed to L. salmonis was modulated by reduced rations. There was a reduction in the expression of interleukin-8 in pink salmon on reduced rations 7 d after exposure but not 14 d after exposure. In contrast, the 7-d expression of interleukin-1 beta (IL-1beta) was reduced in exposed pink salmon regardless of ration. By day 14, however, expression of IL-1beta was increased in association with reduced rations among exposed salmon. Similarly, the expression of tumor necrosis factor alpha (TNFalpha) was increased 14 d after exposure among salmon on a reduced ration. There was no evidence that short-duration exposure of otherwise healthy juvenile pink salmon to a reduced ration affected susceptibility to L. salmonis. The expression data do not suggest an obvious mechanism of louse rejection; rather, they indicate that a more comprehensive suite of inflammatory pathways should be surveyed to better understand the early pink salmon response to L. salmonis.     

饲用植酸酶的基因工程

植酸酶即肌醇六磷酸水解酶,是催化植酸及植酸盐水解成肌醇与磷酸(或磷酸盐)的一类酶的总称(Ullah AH.,1996)。植酸酶广泛存在于微生物、植物和动物中,但猪与家禽等单胃动物体内缺乏该酶。目前商品化的植酸酶均来源于微生物,主要有黑曲霉(Aspergillus niger)(EC3.1.3.8)、无花果     

我国转基因饲料安全问题和应对措施

饲料安全即是食品安全 ,英国的疯牛病和比利时的二恶英事件 ,都为饲料安全敲响了警钟。现已有大量的转基因饲料为动物所食用 ,转基因饲料安全评价成为转基因食品安全的重要环节 ,对转基因饲料安全问题进行全面评价迫在眉睫。这些问题包括转基因产物可能具有的直接毒性或抗营养作用 ,对肠道微生物的生态学和新陈代谢的间接或意料之外的作用 ,以及可能发生的转基因对肠道固有微生物区系的进一步基因转移。由于对这些问题尚无明确结论 ,因此国际上要求饲料中不含转基因生物的呼声日渐高涨 ,欧盟为此制定了相应的限制法规 ,并要求对转基因产品进…     

Early-age feed restriction affects viability and gene expression of satellite cells isolated from the gastrocnemius muscle of broiler chicks

Background: Muscle growth depends on the fusion of proliferate satellite cells to existing myofibers. We reported previously that 0-14 day intermittent feeding led to persistent retardation in myofiber hypertrophy. However, how satellite cells respond to such nutritional insult has not been adequately elucidated. Results: One-day-old broiler chicks were allocated to control (Con, ad libitum feeding), intermittent feeding (IF, feed provided on alternate days) and re-feeding (RF, 2 days ad libitum feeding after 12 days of intermittent feeding) groups. Chickens were killed on Day 15 and satellite cells were isolated. When cultured, satellite cells from the IF group demonstrated significant retardation in proliferation and differentiation potential, while RF partly restored the proliferation rate and differentiation potential of the satellite cells. Significant up-regulation of insulin like growth factor I receptor (IGF-IR) (P<0.05) and thyroid hormone receptor α (TRα) (P<0.05), and down-regulation of growth hormone receptor (GHR) (P<0.01) and IGF-I (P<0.01) mRNA expression was observed in freshly isolated IF satellite cells when compared with Con cells. In RF cells, the mRNA expression of IGF-I was higher (P<0.05) and of TRα was lower (P<0.01) than in IF cells, suggesting that RF restored the mRNA expression of TRα and IGF-I, but not of GHR and IGF-IR. The Bax/Bcl-2 ratio tended to increase in the IF group, which was reversed in the RF group (P<0.05), indicating that RF reduced the pro-apoptotic influence of IF. Moreover, no significant effect of T 3 was detected on cell survival in IF cells compared with Con (P<0.001) or RF (P<0.05) cells. Conclusions: These data suggest that early-age feed restriction inhibits the proliferation and differentiation of satellite cells, induces changes in mRNA expression of the GH/IGF-I and thyroid hormone receptors in satellite cells, as well as blunted sensitivity of satellite cells to T3 , and that RF partially reverses these effects. Thus, a moderate nutritional strategy for feed restriction should be chosen in early chick rearing systems.     

粒细胞-巨噬细胞集落刺激因子(GM-CSF)基因的克隆、原核表达及生物活性鉴定

为了探讨粒细胞-巨噬细胞集落刺激因子(GM-CSF)在免疫中的作用,根据GenBank上发表的鸡GM-CSF基因序列设计特异引物,采用RT-PCR法对球虫免疫后的海蓝灰蛋鸡盲肠扁桃体中GM-CSF基因进行克隆和序列分析;设计GM-CSF原核表达引物,原核表达GM-CSF融合蛋白,通过菌体裂解,包涵体的洗涤、溶解、复性后,过Sepharose4B柱纯化融合蛋白,采用抗病毒试验和淋巴细胞增殖试验检测表达蛋白的生物活性。结果显示,从人工感染柔嫩艾美耳球虫的海蓝灰蛋鸡盲肠扁桃体中扩增到了435bp的DNA片段;序列分析表明其与GenBank中报道的鸡GM-CSF序列仅有1个碱基的差异,与哺乳动物的同源性在35.2%～45.4%;原核表达了海蓝灰蛋鸡GM-CSF,分离纯化的融合蛋白在抗病毒活性试验和淋巴细胞增殖试验中证明具有一定的生物学活性。