不同基因型生长肥育猪可消化赖、蛋+胱、苏、色氨酸平衡模式研究

试验比较研究了平均体重(33.64±1.2)kg 的大白×长白生长猪与平均体重(32.5±0.8)kg 的雅南猪可消化赖、蛋 +胱、苏、色氨酸平衡模式。按照氨基酸(AA)部分扣除氮沉积比较法 ,分别用18头大长猪和18头雅南猪进行N平衡试验。每个N平衡试验均设6个处理组 ,即高蛋白基础饲粮组(BD)、低蛋白加合成氨基酸对照组(PC)、在PC基础上轮流将所研究的4种AA扣除25 %的其它4个试验组。每个处理设3个重复 ,每个重复1头猪。饲粮为玉米—豆粕—玉米蛋白粉型。所有饲粮等能(3.40McalDE/kg) ,基础饲粮CP与可消化Lys水平相应为161g/kg、5.28g/kg。试验期大长猪日喂料120g/kgW 0.75,雅南猪日喂料100g/kgW 0.75。试验结果表明 ,按单位代谢体重的N沉积与可消化AA摄入量计算 ,大长猪AA平衡比例为 :Lys100、Met +Cys49、Thr72、Trp19 ;雅南猪为 :Lys100、Met+Cys78、Thr76、Trp21。结果显示 ,饲粮可消化氨基酸平衡模式因猪的基因型不同而异。与外种猪比较 ,雅南猪需要比较高比例的蛋 +胱、苏氨酸和色氨酸。     

应用合成氨基本以改善生长猪对低蛋白杂粕型饲粮利用效果的研究

将80头生长猪(29.49±1.8kg)按照来源不同、体重相近、公母各半的原则随机分进不同的圈，每处理4圈，每圈4头。试猪均为自由采食、自由饮水，试期6周。应用人工合成赖氨酸(Lys)、蛋氨酸(Met)、苏氨酸(Thr)和色氨酸(Trp)来平衡日粮氨基酸之间的相对比例。试验日粮共分5种即16CP%(对照)，14CP+Lys(处理1)，14%CP+Lys+Met(处理2)，14%CP+Lys+Met+Thr(处理3)和14%CP+Lys+Met+Thr+Trp(处理4)。准确测定试猪体重和饲料消耗以计算日增重、采食量和饲料转化率。在3周末每圈取2头进行前腔静脉采血以测定血清尿素氮含量。结果表明各处理间采食量无明显差异。在低蛋白日粮中随着Lys、Met、Thr和Trp的依次添加猪的日增重和饲料转化率线性改进(P<0.01)，血清尿素氮含量线性下降(P<0.01)。其中处理3和处理4两组猪的日增重分别比对照提高63.75和113.75g。     

30～38周龄产蛋鸡理想氨基酸模式的研究

本试验旨在通过4个剂量-反应试验,研究30～38周龄产蛋鸡对赖氨酸(Lys)、蛋氨酸(Met)、色氨酸(Trp)和苏氨酸(Thr)4种必需氨基酸(AA)的需要量及其比例.每个试验均采用360只海兰灰产蛋鸡,设5个处理,分别采食5个AA梯度水平的试验饲粮,每个处理6个重复,每个重复12只鸡.采用蛋公鸡回肠食糜法测定饲料原料的标准回肠可消化(SID)值.试验预试期14 d,正试期56 d.结果表明:海兰灰产蛋鸡的产蛋率、蛋重、日产蛋量和料蛋比与SIDLys、SID Met、SID Trp和SID Thr的摄入水平均有较好的折线回归关系;以日产蛋量为自变量(x),AA摄入水平为依变量(Y)分别建立的回归方程为:YSID Lys=51.60-0.041 6(682.5-x),R2=0.96;YsID Met=51.43-0.085(314.1-x),R2 =0.95;YSID Trp =51.17-0.155 4(163.0-x),R2=0.97;YsID Thr=52.85-0.057 6(499.5-x),R2=0.93.在饲粮粗蛋白质12.8％的条件下,以日产蛋量为参照指标确定的30 ～ 38周龄产蛋鸡的SID Lys、SID Met、SID Trp和SID Thr需要量分别为684、313、171和506 mg/(只·d).以日产蛋量为指标建立的30～38周龄产蛋鸡理想SID AA模式为:Lys:Met:Trp:Thr=100∶46∶24∶73.     

肉仔鸡菜籽粕氨基酸标准回肠消化率的评定及预测方程的建立

本试验旨在分析湖南省6种不同地区菜籽粕的18种氨基酸含量,测定14和28日龄肉仔鸡对6种不同地区菜籽粕中氨基酸的标准回肠消化率,并建立赖氨酸、蛋氨酸、色氨酸及苏氨酸标准回肠消化率的预测方程。试验共选取700羽体重和健康状况一致的1日龄爱拔益加(AA)肉仔鸡,根据日龄分别进行2个阶段的试验。第1阶段(7～14日龄):将420羽肉仔鸡随机分为7个处理,每个处理10个重复,每个重复6羽;第2阶段(21～28日龄):将280羽肉仔鸡随机分为7个处理,每个处理10个重复,每个重复4羽。2个阶段中的7个处理分别为6个不同地区的菜籽粕采用全替代法设计的试验饲粮组和1个无氮饲粮组。分别在14和28日龄收集试验鸡回肠食糜用于测定菜籽粕氨基酸标准回肠消化率并通过回归分析建立预测方程。结果显示:14和28日龄肉仔鸡对菜籽粕中18种氨基酸标准回肠消化率的平均值波动范围分别为63.26%～79.58%和66.22%～80. 34%。14日龄肉仔鸡对菜籽粕中赖氨酸、蛋氨酸、苏氨酸和色氨酸标准回肠消化率的预测方程分别为Lys=-90.81+4.562CP(R~2=0. 792,P 0. 05)、Met=110.644-2.810CF(R~2=0.845,P0.05)、Trp=106.834-0.725NDF(R~2=0.989,P 0.05)和Thr=-79.357+4.284CP(R~2=0.715,P0.05); 28日龄肉仔鸡对菜籽粕中赖氨酸、蛋氨酸、苏氨酸和色氨酸标准回肠消化率的预测方程分别为Lys=161.02-2.002NDF(R~2=0. 957,P 0. 05)、Met=144.269-1.521NDF(R~2=0.831,P0.05)、Trp=112.053-0.824NDF(R~2=0.999,P0.05)和Thr=99.983-2.566CF(R~2=0.712,P0.05)。上述预测方程中:Lys为赖氨酸标准回肠消化率; Met为蛋氨酸标准回肠消化率; Trp为色氨酸标准回肠消化率; Thr为苏氨酸标准回肠消化率; CP为粗蛋白质含量; CF为粗纤维含量; NDF为中性洗涤纤维含量。本试验通过分析粗蛋白质、粗纤维及中性洗涤纤维含量与氨基酸标准回肠消化率的相关关系,建立了14和28日龄肉仔鸡对湖南省菜籽粕中赖氨酸、蛋氨酸、色氨酸和苏氨酸标准回肠消化率的预测方程,可为菜籽粕在肉仔鸡饲粮中的高效利用提供便利。     

苏氨酸在养猪生产中的应用

苏氨酸(Thr)自1935年从纤维蛋白水解的产物中分离和鉴定出来,并证明是最后发现的必需氨基酸(EAA).此后,人们对Thr的营养代谢作用进行了大量研究.通常认为,在猪的实用日粮中,Thr是第二或第三限制性氨基酸.随着赖氨酸(Lys)、蛋氨酸(Met)合成品在配合饲料生产中得到广泛应用,使得Lys、Met不再是常规型日粮的主要限制性氨基酸,Thr在猪日粮中的缺乏,对猪的生产性能的影响也日渐突出.Hansen等(1993)研究表明,在低蛋白高粱-豆粕基础日粮中添加合成Lys后,Thr成为生长猪的第一限制性氨基酸,因此,对Thr的营养代谢的进一步探讨也显得极为必要,本文特对Thr的应用作一综述,以便有效的指导饲料生产.     

不同生理阶段犊牛赖、蛋、苏氨酸平衡模式研究

应用部分扣除饲粮氨基酸(AA)的氮平衡试验法研究了中国荷斯坦犊牛不同生理阶段(2～3周龄和5～6周龄)赖(Lys)、蛋(Met)、苏氨酸(Thr)平衡模式。每个阶段各用12头犊牛进行N平衡试验。每个N平衡试验均设4个处理组,即氨基酸相对平衡的代乳品(PC)组(赖氨酸、蛋氨酸、苏氨酸含量依次为2.34%、0.72%、1.80%)、在PC基础上轮流将赖、蛋、苏氨酸扣除30%的其它3种代乳品(分别为PC-Lys、PC-Met、PC-Thr)组。每个处理设3个重复,每个重复1头牛。所有代乳品等能(17.8MJ/kg)等蛋白(22%)。试验结果表明,按单位代谢体重的N沉积与氨基酸摄入量计算,中国荷斯坦犊牛2～3周龄日粮模式为代乳品时,Lys、Met、Thr的平衡比例100:29:70;5～6周龄日粮模式为代乳品、开食料和羊草时,平衡比例为100:30:60;两阶段3种氨基酸的限制性顺序均为Lys、Met、Thr。     

低蛋白质氨基酸平衡日粮对妊娠后期母猪繁殖性能、血清生化指标和氮排泄量的影响

本试验探讨在理想氨基酸模式下,低蛋白质氨基酸平衡日粮对妊娠后期母猪繁殖性能、血清生化指标和氮排泄量的影响。选用3～7胎次、体况相似、预产期相近的60头长大二元杂交母猪,随机分成2个处理组:对照组(CP为15.0%,可消化赖氨酸水平为0.73%)和试验组(CP为13.0%,可消化赖氨酸水平为0.63%)。通过添加赖氨酸、蛋氨酸、色氨酸、苏氨酸保证2个处理组饲料中可消化赖氨酸:可消化苏氨酸:可消化蛋氨酸:可消化色氨酸的比值(100:72:27:16)一致。每处理30个重复,每重复1头母猪。试验期始于配种后80 d,终于产仔结束。结果表明,试验组的初生窝重比对照组显著增加9.68%(P0.05),试验组血清尿素氮、游离赖氨酸、苏氨酸和异亮氨酸浓度显著低于对照组(P0.05),粪氮排泄量显著减少(P0.05)。     

断奶羔羊4种必需氨基酸限制性顺序和需要量模型探索

本试验旨在采用氨基酸部分扣除法研究断奶羔羊的4种必需氨基酸的限制性顺序和需要模型。选取50日龄断奶湖羊公羊100只随机分为5组,每组4个重复,每个重复5只羊。对照组为氨基酸平衡(PC)组,饲喂氨基酸平衡的开食料,4个试验组开食料在PC组的基础上分别扣除赖氨酸(PD-Lys组)、蛋氨酸(PD-Met组)、苏氨酸(PD-Thr组)和色氨酸(PD-Trp组),其余氨基酸含量保持一致。预试期为10 d,正试期为60 d。于羔羊60、90和120日龄称量体重,在120日龄每组随机选取6只羔羊进行屠宰。结果表明:1)60~120日龄和90~120日龄,PD-M et组羔羊平均日增重(ADG)显著低于其他各组(P0.05),饲料转化率(F/G)显著高于其他各组(P0.05);120日龄时,PD-Met组宰前活重、空体重、胴体重、眼肌面积、头重、蹄重及皮毛重均显著低于PC、PD-Thr和PD-Trp组(P0.05),但是5组间屠宰率(DP)、GR值和血液重差异不显著(P0.05)。2)以最佳ADG和F/G为评价指标时,60~90日龄和90~120日龄氨基酸限制性顺序为Met、Lys、Thr和Trp;而以最佳DP为评价指标时,120日龄氨基酸的限制性顺序为Trp、Thr、Lys、Met。3)以最佳ADG作为评价指标时,60~90日龄和90~120日龄Lys、M et、Thr和Trp的适宜比例分别为100∶44∶44∶8和100∶42∶38∶12;以最佳F/G作为评价指标时,60~90日龄和90~120日龄Lys、M et、Thr和Trp的适宜比例分别为100∶54∶45∶7和100∶47∶39∶12;以最佳DP为评价指标时,60~120日龄Lys、M et、Thr和Trp的适宜比例为100∶34∶38∶8。总之,饲粮必需氨基酸(Lys、Met、Thr和Trp)缺乏严重影响湖羊断奶羔羊的生长性能、屠宰性能和器官指数,特别是Met影响最为明显,其次是Lys,Thr和Trp影响较弱;不同评价指标(ADG、F/G和DP)和不同生长阶段得出的Lys、M et、Thr和Trp的限制性顺序和需要模型是不同的。     

鱼类赖氨酸营养研究进展

鱼类和大多数陆生动物一样,维持正常的生长代谢需要10种必需氨基酸,这10种必需氨基酸分别是:蛋氨酸(Met)、赖氨酸(Lys)、亮氨酸(Leu)、异亮氨酸(Ile)、苏氨酸(Thr)、苯丙氨酸(Phe)、色氨酸     

肉仔鸡饲粮中蛋氨酸和半胱氨酸与赖氨酸适宜比例的研究

本试验旨在研究饲粮中不同(蛋氨酸+半胱氨酸)/赖氨酸[( Met+ Cys)/Lys]比例对内仔鸡生长性能和经济效益的影响,探讨肉仔鸡饲粮中适宜的( Met+Cys)/Lys比例.选取1日龄罗斯308商品肉仔鸡3 600只,随机分为4个饲粮处理,( Met+ Cys)/Lys比例分别为0.64、0.68、0.72和0....     

An analysis of a stocking rate trial at Chobela,southern Mozambique

Abstract

An analysis is presented of data from a stocking rate trial carried out in 1962–1963 at Chobela Livestock Station in southern Mozambique. The data set had limitations but an attempt was made to draw any conclusions possible for management. Data from the trial showed optimum gains per hectare at 0.64 head ha^‐1 (approximately 1.8 ha LSU^‐1) in years of below‐average rainfall, and an annual livemass gain of 146 kg head^‐1 at a stocking rate of 0.33 head ha^‐1 (approximately 4.2 ha LSLT^‐1). Potential livestock carrying capacity was determined using a model developed in Mozambique, and the calculated value of 4.3 ha LSLT^‐1 for a similar livemass gain was close to that determined from the trial data.     

三种聚醚类抗生素促进育肥肉牛增重的比较试验

将30头平均体重为435.8kg的夏洛来牛×南阳牛F1分为三组,在饲喂麦秸、啤酒糟和日补精料6.14kg的条件下,分别添加莫能菌素、沙拉里菌素和盐霉素进行饲养试验。结果,莫能菌素、沙拉里菌素和盐霉素组的平均日增重分别为1.20、1.07、1.11kg/d;料重比分别为5.13:1、5.75:1和5.52:1;单位增重的增重剂成本分别为0.073元,0.064元和0.145元。     

A double‐blind,placebo‐controlled,randomized study to evaluate the weight gain drug,mirtazapine transdermal ointment,in cats with unintended weight loss

Mirtazapine is classified as a weight gain drug in cats, and the purpose of this study was to evaluate its efficacy in cats experiencing unintended weight loss. This was a multi‐center, double‐blind, placebo‐controlled, randomized clinical study in client‐owned cats ≥1 year of age, weighing ≥2 kg, with a documented loss (≥5%) in body weight. Cats were treated once daily with either 2 mg/cat mirtazapine transdermal ointment (n = 83) or placebo (n = 94) (Per Protocol population) applied to the inner surface of the pinna for 14 ± 3 days. Physical examination, body weight, complete blood count, serum chemistry, and urinalysis were performed prior to treatment and on Day 14. Changes in body weight between the mirtazapine and placebo groups were evaluated from Day 1 to Day 14 and compared using a two‐sample t test. The mean percent change in body weight was +3.9% (standard deviation ±5.4%) in the mirtazapine group and +0.4% (±3.3%) in the placebo group (p < 0.0001). The most common adverse event was mild erythema at the application site in 17.4% of placebo and 10.4% of mirtazapine‐treated cats. Application of mirtazapine transdermal ointment was well tolerated both topically and systemically and resulted in significant weight gain in cats experiencing unintended weight loss associated with various underlying diseases.     

Effect of long-term feeding of graded levels of deoxynivalenol (DON) on growth performance,nutrient utilization,and organ health in finishing pigs and DON content in biological samples

The prevalence of deoxynivalenol (DON) is a concern for swine producers, and although there has been extensive research into the effects of DON in pigs, focus has been in young pigs and/or in short-term studies. The objective of the study was to determine the effect of long-term exposure to DON-contaminated diets in finisher pigs. A total of 200 pigs (76.6 ± 3.9 kg initial weight) were group housed (five pigs per pen; n = 10 pens/treatment) in a 6-wk trial. Pigs were fed a wheat-barley-soybean meal-based control (CONT) diet with no DON or the basal diet in which clean wheat was replaced by DON-contaminated wheat and wheat screenings to provide DON content of 1, 3, or 5 ppm (DON1, DON3, and DON5, respectively). Individual BW and pen feed intake were recorded weekly to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F). Blood was collected on days 0, 14, and 43 and analyzed for indicators of liver and kidney health. Nitrogen (N)-balance was conducted immediately following the growth performance period to determine the effect of DON on nutrient utilization. Blood and urine samples collected during N balance were analyzed for DON content. Feeding DON reduced (P < 0.05) ADFI and ADG from days 0 to 28 compared with CONT, after which there was no effect of diet on ADFI and ADG. The G:F was lower (P < 0.05) in DON5 fed pigs compared with all treatments during days 0 to 7; however, no treatment effects on G:F was observed from days 8 to 42. Nitrogen retention was lower (P < 0.05) in DON3 and DON5 compared with DON1-fed pigs. Nitrogen retention efficiency was higher (P < 0.05) in DON1 compared with DON3 and DON5 and protein deposition for DON1 pigs was higher (P < 0.05) than all treatments. There were no treatment effects on indicators of liver and kidney health. As dietary DON intake increased, concentration of DON in blood and urine increased. Overall, although there was an initial decrease in ADG and ADFI in pigs receiving diets containing >1 ppm DON, pig performance recovered after a period of time, whereas nutrient utilization continued to be affected after recovery of performance. Moreover, the lack of DON on G:F indicates that the negative effects of DON on growth performance are largely due to reduced feed intake. Overall, although pigs maybe capable of adapting to intake of DON-contaminated diets, their final body weight will be reduced when fed diets containing >1 ppm DON.     

Early feed restriction in broilers. II: Body composition and nutrient gain

Two experiments were performed, in male and female broilers separately, to evaluate the effect of early feed restriction on the composition, gain, and efficiency of nutrients retention by comparative slaughter. Treatments were applied from 8 to 16 d age as follows: without feed restriction [standard feed (SF) ad libitum]; quantity restriction (80% ad libitum consumption of SF); time restriction (SF offered throughout 8 h/d); and quality restriction (SF diluted with 10% kaolin and 10% rice hulls containing 80% of the limiting nutrients). The broilers were raised in pens and 6 replications/treatments were used. The composition and body gain of DM, CP, and EE, and efficiency of protein and energy retention were evaluated. Time restriction was considered the most severe, mainly in males that showed less protein gain at 42 d age. Proportional body gain of EE was higher than that of CP in the refeeding period in the quantity and time restricted broilers and no improvement in the protein retention efficiency was observed in those birds previously restricted. The possibility that feed restriction decreases carcass fat was not observed.     

锌、硒、钴水平及复合饲料添加剂对肉牛增重的影响

制备含锌、硒、钴高水平 (10 0、0 .4、0 .4 PPM)和低水平 (30、0 .2、0 .1PPM)两种复合饲料添加剂 ,并以某商品饲料添加剂为对照。选用 2 8头体重 2 75～ 30 0 kg的夏洛来×南阳牛 F1,在饲喂氨化麦秸、日补混合精料 1.75kg条件下进行饲养试验。结果表明 ,在该饲料类型下牛的日增重处于0 .5～ 0 .7kg;锌、硒、钴高水平组、低水平组和商品饲料添加剂组的平均日增重分别为 0 .6 6 8、0 .4 94和 0 .56 4 kg,三组的精料增重比分别为 2 .6 2 :1、3.54:1和 3.0 2 5:1     

Nitrogen fertilization,stocking rate and rotational grazing effects on steers grazing Pennisetum clandestinum

Kikuyu pastures at the Ukulinga research farm near Pietermaritzburg were fertilized with 150 and 300 kg nitrogen (N) ha^?1 in the summer periods of 1985–86 and 1986–87, and were continuously grazed with steers at stocking rates of 5.4, 8.0 and 10.7 steers ha^?1. In the second season the high N level pasture was also grazed under 12‐paddock rotational grazing at stocking rates of 5.4, 8.0 and 13.4 steers ha^?1. In the first season the high N level provided higher (P≤0.05) animal weight gains, but there was no difference between N levels in animal weight gain during the second season. Rotational grazing provided higher weight gains than continuous grazing in the second season. The increased weight gains obtained from high N fertilization and rotational grazing were probably caused by higher forage availability rather than higher forage quality.     

Serum IgG,blood profiles,growth and survival in goat kids supplemented with artificial colostrum on the first day of life

The objective of this study was to compare serum IgG concentrations, blood metabolites indicative of nutritional status, weight gain and mortality rate in goat kids fed a commercial colostral supplement containing immunoglobulins against several pathogen microorganisms, prior to the ingestion of the mother colostrum, and goat kids ingesting natural colostrum only. There was no difference in serum IgG concentrations between 27 kids fed a colostrum supplement (20 g, derived from cow lacteal secretions) prior to the kids’ first meal (658 ± 703 mg dl⁻¹) and 21 kids ingesting maternal colostrum freely (1011 ± 1140 mg dl⁻¹) at 24 hours of birth. Hematocrit values, serum glucose and urea concentrations at 24 hours and 5 days of age were unaffected by treatment. Serum total proteins were 14% higher (P < 0.05) in the unsuplemented group than in the supplemented group at 5 d of age. There was no significant difference between the supplemented and unsupplemented kids in daily weight gain from birth to 70 days of age (92 ± 4.8 vs 102 ± 5.1 g day⁻¹). Mortality was 4% for kids receiving the colostrum supplement as compared with 0.0% for kids ingesting maternal colostrum only. Results suggest that, in intensively managed non-dairy goats with kiddings in summer, the supplementation of this commercial colostrum derived from cow lacteal secretions and containing antibodies against diverse pathogens organisms did not enhanced growth, survival or immunity under the farming conditions of this study.     

青贮,微贮,氨化与干玉米秸对育肥牛增重效果研究

为检验青贮、微贮、氨化与干玉米秸对育肥牛增重效果的差异,本试验选择改良去势公牛４８头,随机分为青贮组,微贮组、氨化组与对照组,经７０ｄ试验,结果表明,青贮组,微贮组与氨化组增重效果的均高于对照组,差异显著,但青贮组、微贮组与氨化组三者之间差异不显著,而以青贮组效果最好,微贮组次之,青贮组比对照组头日净增重多０．２４ｋｇ,增重效果提高２４．７８％,头日净增益多１．９８元,经济效益显著。