快速型黄羽肉鸡饲料利用效率性状的基因组选择研究

旨在探究快速型黄羽肉鸡饲料利用效率性状的遗传参数,评估不同方法所得估计育种值的准确性.本研究以自主培育的快速型黄羽肉鸡E系1923个个体(其中公鸡1199只,母鸡724只)为研究素材,采用"京芯一号"鸡55K SNP芯片进行基因分型.分别利用传统最佳线性无偏预测(BLUP)、基因组最佳线性无偏预测(GBLUP)和一步法...     

饵料类型对岱衢族大黄鱼鱼体和肌肉营养成分、体色、肉色的影响

岱衢族大黄鱼为我国优质大黄鱼养殖群体,养殖中所投喂的饵料往往影响着鱼体和肌肉营养成分、体色和肉色,这些均为衡量岱衢族大黄鱼品质的重要指标.本试验旨在通过测定岱衢族大黄鱼鱼体和肌肉营养成分、体色和肉色指标,研究投喂鲜杂鱼和配合饲料对岱衢族大黄鱼品质的影响.试验设置2组,分别投喂鲜杂鱼和配合饲料22个月,采样后所测鱼体和肌肉营养成分指标包括干物质、粗蛋白质、粗脂肪、粗灰分和氨基酸含量,体色和肉色指标包括L、a、b值.结果表明:与投喂鲜杂鱼相比,投喂配合饲料显著降低了岱衢族大黄鱼全鱼的粗脂肪含量(P＜0.05),但显著提高了肌肉的粗脂肪、亮氨酸(Leu)、赖氨酸(Lys)、谷氨酸(Glu)、总必需氨基酸、总呈味氨基酸和总氨基酸含量(P＜0.05);饵料类型对岱衢族大黄鱼的体色和肉色无显著影响(P＞0.05),但岱衢族大黄鱼体表不同部位颜色存在显著差异(P＜0.05),与背部相比,腹部的颜色较亮,且偏红黄.由此得出,相较于鲜杂鱼,采用配合饲料养成的岱衢族大黄鱼肌肉具有更高的营养价值.     

饲料级果胶酶对肉仔鸡生长性能的影响

试验旨在研究日粮中添加饲料级果胶酶对肉仔鸡生长性能的影响。选择体重、健康状况基本一致的AA肉仔鸡240只,随机等分为试验组与对照组2个组,每组设3个重复,每重复40只,分成2个处理组,试验组饲喂在基础日粮中添加0.01％含6000U/g 的饲料级果胶酶的日粮,进行为期35d的试验。结果表明,与对照组相比,试验组日增重提高9.51％（P〈0.05）;料重比降低7.06％（P〈0.05）;死淘率降低11.00％（P〈0.05）。说明在日粮中添加饲料级果胶酶可显著提高肉仔鸡的生长性能。     

Quality versus quantity: spring wheat seed size and seeding rate effects on Avena fatua interference, economic returns and economic thresholds

A 3-year field experiment was conducted at Kalispell, Montana, USA, to investigate the effects of spring wheat seed size and seeding rate on wheat yield loss (YL), economic returns and economic thresholds (ETs), as a function of Avena fatua density. Crop competitive ability increased as wheat seeding rate and seed size increased, with the greatest differences among treatment factors being observed at low weed densities. Both treatment factors decreased spring wheat YL, increasing economic returns during all 3 years of the study despite the higher associated seed costs. Averaged over all other factors, adjusted gross returns (AGR) were 477 and 537$ ha⁻¹ for the low and high seeding rates, while values of 453, 521 and 547$ ha⁻¹ were obtained for the small, bulk and large seed size classes respectively. Weed-free yield potential varied yearly. As yield potential increased, A. fatua competitive effects were more evident and ETs decreased. Nonetheless, both treatment factors increased ETs in 2 of 3 years. These results demonstrate that the use of higher seeding rates and larger seed size classes both improve wheat competitive ability towards A. fatua while simultaneously increasing economic returns.     

Endocannabinoid system and proopiomelanocortin gene expression in peripartal bovine liver in response to prepartal plane of nutrition

Endocannabinoids are fatty acid amides (FAE; oleoylethanolamide and anandamide) which have orexigenic, anorexigenic or anti‐inflammatory properties. We examined mRNA expression via qPCR of endocannabinoid receptors (CNR1 and CNR2), enzymes that synthesize FAE (HRASLS5 and N‐acyl phosphatidylethanolamine phospholipase D), enzymes that degrade FAE [fatty acid amide hydrolase (FAAH), N‐acylethanolamine acid amidase (NAAA) and monoglyceride lipase (MGLL)], and the hormone precursor proopiomelanocortin (POMC) in liver at ?14, 7, 14 and 30 days around parturition from cows fed with a control (CON; NE_L = 1.34 Mcal/kg) or moderate‐energy (OVER; NE_L = 1.62 Mcal/kg) diet during the dry period. Expression of CNR2 and POMC was greater at 7 days in cows fed with OVER because of a decrease in expression between ?14 and 7 days in cows fed with CON. Cows fed with CON had an increase in expression of FAAH, HRASLS5, NAA, MGLL and POMC between 7 and 14 days; for FAAH and HRASLS5, such response led to greater expression at 14 days vs. cows fed with OVER. Cows fed with OVER vs. CON had a approximately twofold increase in expression of MGLL between ?14 and 7 days followed by a gradual decrease through 30 days at which point expression was still greater in OVER vs. CON. FAAH, MGLL and HRASLS5 were the most abundant genes measured. Expression of the hepatic endocannabinoid system and POMC was altered by plane of dietary energy prepartum particularly during the first 2‐week postpartum. Such responses may play a role in the physiological adaptations to the onset of lactation, including energy balance and feed intake.     

地塞米松和饲粮能量水平对肉仔鸡能量采食及神经肽Y基因表达的影响

本试验旨在探讨注射地塞米松(DEX)模拟应激状态下,应激和饲粮能量水平对肉仔鸡能量采食的影响。选取体重相近的180只23日龄的雄性爱拔益加(AA)肉鸡随机分成6组,每组3个重复,每个重复10只鸡。试验采用2×3析因设计,因素为DEX[处理(注射DEX2 mg/kg)、未处理(注射等剂量生理盐水)]和饲粮能量水平[高能(HE)、低能(LE)以及高能、低能自由采食(H-LE)]。预试期5 d,正试期7 d。结果表明:1)DEX处理极显著降低了肉仔鸡的采食量和体增重(P<0.01),极显著提高了耗料增重比、耗能增重比、腹脂率以及血浆葡萄糖、甘油三酯和尿酸的浓度(P<0.01),显著提高了肠道指数(P<0.05)。2)采用LE饲粮体增重(P<0.05)、腹脂率(P<0.01)显著低于其他2种饲粮,耗料增重比显著低于HE饲粮(P<0.05);采用HE饲粮耗能增重比极显著高于其他2种饲粮(P<0.01);采用H-LE饲粮神经肽Y(NPY)基因表达量显著高于LE饲粮(P<0.05)。3)DEX、饲粮能量水平对耗料增重比(P<0.05)和耗能增重比(P<0.01)的影响存在显著的互作效应。结果提示,DEX应激可使肉仔鸡血浆中葡萄糖、尿酸和甘油三酯的浓度升高;DEX应激和HE饲粮均能增加脂肪在腹部沉积,提高耗料增重比和耗能增重比;H-LE饲粮能上调肉仔鸡下丘脑NPY基因表达。     

羽毛粉加工工艺与开发

羽毛粉加工产品目前是饲料行业的主要蛋白原料,为了更好地促进羽毛粉的加工利用,提高羽毛粉加工产品的营养价值,结合目前各大中型企业的具体生产工艺,介绍了高温高压水解法、酶解—水解法和生物发酵法3种方法的生产工艺流程、工艺条件及所生产产品的质量特点。通过对比上述方法,说明生物发酵法是未来羽毛粉深加工的理想方法。     

日粮中添加味精菌体蛋白对奶牛生产性能的影响

试验选用2～4胎次泌乳中期荷斯坦牛18头,随机分为3组,每组6头,试验1组和试验2组分别给每头奶牛添加5%和15%的味精菌体蛋白,对照组不添加味精菌体蛋白,以评定味精菌体蛋白对奶牛生产性能的影响。结果表明,夏季奶牛日粮中添加味精菌体蛋白替代日粮中部分蛋白质饲料,可促进奶牛粗饲料采食量的增加,减缓热应激造成的产奶量下降幅度,但对牛奶品质的影响不大。     

甜菊糖甙对哺乳仔猪生产性能和健康状况的影响

为研究天然甜菊糖甙作为新型甜味剂在哺乳仔猪中的应用效果,随机选取16窝哺乳仔猪(杜长大,10头/窝)分为4组,每组4个重复,分别饲喂添加0、100、200和500g/t天然甜菊糖甙的教槽料,试验从仔猪7d时开始,至断奶后1周(28d)结束,期间每隔7d对仔猪采食量、增重和健康状况进行测定。结果发现,在哺乳仔猪日粮中添加100、200和500g/t的甜菊糖甙,显著提高仔猪断奶重(21d)和28d体重(P0.05),显著提高14～21和22～28d阶段内的平均日增重、平均日采食量和偏嗜指数(P0.05),而各甜味剂添加组间无显著性差异(P0.05)。7～28d内仔猪日增重200g/t组显著高于对照组和100g/t组。仔猪断奶(21d)后1周内腹泻率和腹泻指数有改善趋势(P0.05),7～28d内仔猪发病率200和500g/t天然甜菊糖甙组显著降低(P0.05)。因此,考虑成体投入的同时,在哺乳仔猪日粮中添加200g/t的天然甜菊糖甙,可取得良好的应用效果。     

稻麦变量施肥机控制系统设计与试验

针对稻麦变量施肥智能化程度低、通信系统可靠性和兼容性差等问题,研究设计了一种稻麦变量施肥机控制系统。该系统以CAN总线通讯作为现场总线,实现各控制节点之间的实时通信;通过GPS导航和处方图得到当前位置需肥量,根据变量施肥数学模型,通过步进电机节点实时调节外槽轮排肥器开度,实现施肥变量调节。试验结果表明:该系统机械结构设计合理,动作响应迅速,定位精准,各行排肥器之间排肥量变异系数最大为1. 78%,变量施肥精度达97%以上,作业效果良好。其控制程序稳定可靠,各控制节点之间通信及时、准确,整机设计合理,系统工作稳定,智能化程度高,各项技术指标满足农艺要求。