Growth Performance by Stocker Steers Fed Magnesium-Mica During a Grazing and Feedlot Period

Two experiments were conducted to determine the effects of Mg-mica supplementation on grazing and feedlot performance of stocker steers. In Exp. 1, eight groups of six steers were fed a basal diet of 80% ground grain sorghum, 15% corn silage, and 5% control protein supplement (DM basis) or a supplement containing Mg-mica (9% of supplement; 4.5 mg/kg diet DM) for 141 d. Marbling scores tended (P<0.10) to be greater, and the percentage of carcasses grading USDA Choice or higher was greater (P<0.05), from steers fed Mg-mica than from those fed the control supplement. In Exp. 2, eight groups of nine head each were offered either a control grain sorghum-based supplement or one containing 34 g/d of Mg-mica (2.7 g Mg) while grazing smooth bromegrass pastures for 112 d. Pasture groups were then placed in feedlot pens for 120 d and fed a basal diet similar to that described above. Two groups fed each pasture supplement received a control supplement, and two received a supplement containing Mg-mica (10% of supplement; 5 mg/kg diet DM). Steers fed Mg-mica during the pasture phase tended to have heavier (P=0.11) hot carcass weights, higher (P<0.05) dressing percentages, numerically (P>0.10) higher marbling scores, and a higher percentage of carcasses grading USDA Choice than steers fed the control supplement during the pasture phase. Therefore, adding Mg-mica to pasture supplements or feedlot diets appears to have no impact on grazing or feedlot performance, but may improve carcass quality.     

Growth Performance and Serum Prolactin Concentrations of Stocker Steers Implanted with Trenbolone Acetate While Grazing Endophyte-Infected Fescue in the Spring

A 64-d grazing study was conducted with a 2 × 2 factorial arrangement of treatments to evaluate the impact of implant treatment on growth performance, hair score, and serum prolactin levels of steers grazing tall fescue with high (HE) or low (LE) levels of infection with the endophytic fungus Neotyphodium coenophialum. Mixed-breed steers (n = 130; 246 ± 3.5 kg initial BW) were allocated randomly to one of three HE or one of four LE pastures beginning April 13. Within each replication, one-half of the steers were implanted (IMP) with trenbolone acetate (40 mg) and estradiol (8 mg), and one-half were not implanted (NI). No implant treatment × endophyte level interactions were detected (P>0.10). Steers grazing HE had lower (P<0.01) BW gain, inferior (P<0.05) hair scores, and lower (P<0.01) serum prolactin concentrations on d 64 than those steers grazing LE. Total BW gains were greater (P=0.01) from IMP steers than from NI steers, but serum prolactin concentrations and hair scores did not differ (P>0.10) between IMP and NI steers on either d 36 or 64. When tabulated across forage and implant treatments, correlations were negative between overall BW gains and hair scores measured on d 64 (r = 0.28; P<0.01), and positive between overall BW gains and serum prolactin levels measured on d 36 and 64 (r = 0.33 and 0.43, respectively; P<0.001). Therefore, fescue toxicity symptoms were manifested in HE steers, and implanting trenbolene acetate and estradiol improved grazing BW gain, but no endophyte level × implant interactions were detected.     

低聚半乳糖对荷斯坦犊牛生长性能、血清生化指标及矿物质元素含量的影响

本试验旨在研究不同剂量低聚半乳糖(GOS)对荷斯坦犊牛生长性能、血清生化指标及矿物质元素含量的影响,探究适宜犊牛生长的GOS添加剂量.选取32头出生重[(37.7±0.8)kg]相近、健康的新生荷斯坦母犊牛,随机分为4组,每组8头牛.对照组和试验组均饲喂开食料和牛奶,试验组分别在牛奶中添加10(GOS1组)、20(GO...     

不同中性洗涤纤维来源饲粮对荷斯坦公犊牛生长性能、消化代谢和血清生化指标的影响

本试验在饲粮中性洗涤纤维(NDF)水平相同的条件下,研究以苜蓿干草(AH)或大豆皮(SH)为主要NDF来源的全混合日粮对荷斯坦公犊牛生长性能、消化代谢和血清生化指标的影响。选取30头105日龄的荷斯坦公犊牛,按照随机区组设计分成2组,每组15头,分别饲喂AH和SH为主要NDF来源的全混合日粮。预试期15d,正试期60d。结果表明:1)试验全期(120~180日龄),SH饲粮组犊牛的料重比显著低于AH饲粮组(P<0.05);120~135日龄时,SH饲粮组犊牛的平均日增重显著高于AH饲粮组(P<0.05)。2)170日龄时,SH饲粮组犊牛的粪排出量、粪能、尿能和粪氮显著低于AH饲粮组(P<0.05),SH饲粮组犊牛的干物质、有机物、NDF和酸性洗涤纤维的表观消化率显著高于AH饲粮组(P<0.05),SH饲粮组犊牛的总能表观消化率、总能代谢率、消化能代谢率、沉积氮、氮沉积率和氮表观消化率显著高于AH饲粮组(P<0.05)。3)180日龄时,SH饲粮组犊牛的血清β-羟丁酸含量显著低于AH饲粮组(P<0.05)。综上所述,SH是120~180日龄荷斯坦公犊牛较好的NDF来源,能够满足犊牛对营养物质的需要,相比AH饲粮,饲喂SH饲粮能够提高犊牛的营养物质表观消化率及能量和氮的利用率。     

Performance and Economic Returns of Stocker Cattle on Tallgrass Prairie Under Different Grazing Management Strategies

A 4-yr study was conducted to determine performance of stocker calves on tallgrass prairie under three grazing management strategies. Pastures were assigned to one of three grazing treatments. Grazing was initiated in June, and pastures were grazed only during the summer months for 57 to 104 d (79.5 ± 20.7 d). Two of the pastures were grazed season-long. Calves in one of the season-long treatments were fed a protein supplement during the second half of the grazing season; calves in the other season-long treatment were not supplemented (control group). The third pasture, an intensive early stocking (IES) treatment, was grazed at twice the stocking rate used in the season-long pastures for the first half of the grazing season (40 ± 11 d) and rested for the second half (39.5 ± 10 d). Individual stocker performance during the first half of the summer was similar among grazing treatments. Providing supplemental protein during the second half of the grazing season increased BW gain by 30 kg/ha during the last 40 d of the 80-d grazing season and increased BW gain by 12 kg/ha for the entire summer. Over the summer, IES stocker calves produced 24% more gain/ha than season-long stocked calves. Nonetheless, IES management was not more profitable than season-long grazing with or without protein supplementation. Under short-term ownership of calves in the IES system, fixed costs represented a large portion of the total cost.     

Effect of Different Carbohydrate Sources on Growth Performance,Body Size Indexes andNutrients Apparent Digestibility of Beef Calves

The objective of this study was to determine the effect of different carbohydrate sources on growth performance, body size indexes and nutrients apparent digestibility of beef calves. Twenty newborn Black Angus calves were randomly divided into 4 treatments,5 replications per treatment and 1 calve per replication. The calves in control group fed with milk,while that of groups A,B and C fed with glucose,whey powder and ripened corn powder as the main carbohydrate source of milk replacer,respectively. The test was start when the calves were 30 days of age,and the trial period lasted for 45 days. The body weight and body indexes of calves were measured at 30,45,60 and 75 days of age. Two digestion tests were arranged at 35-43 and 65-73 days of age,in addition,the incidence of diarrhea was documented daily. The results showed that the effect of different carbohydrate source on the calves was obvious in the first period. At 30-45 days of age,the average daily gain of group C was extremely significantly lower than that of control group (P< 0.01),and significant lower than groups A and B (P< 0.05),while that of group A was significantly lower than that of control group and group B (P< 0.05).The DM apparent digestibility rate of group C was significantly lower than that of groups A and B (P< 0.05),the apparent digestibility of CP was significantly lower than that of group A (P< 0.05) and extremely significantly lower than that of group B (P< 0.01),diarrhea rate was also high in this period. After 45 days of age,this influence decreased,the average daily gain of groups A and B began to increase,and there was no significant difference compared with control group (P> 0.05). The growth rate of group C increased rapidly,and there was no significant difference of average daily gain compared with group A at 75 days of age (P> 0.05).The nutrient apparent digestibility were improved in the second digestible test,and the diarrhea rate began to decrease which was 0 at the end of the test. During the whole experiment,the different carbohydrate source had little effect on the body indexes. In conclusion,whey powder showed the best effects in the experiment,flowed by glucose and the effect of ripened corn powder was poor in the early,but it became better with the increase of calves' age.     

不同糖源对肉用犊牛生长性能、体尺指数及营养物质表观消化率的影响

试验旨在研究不同糖源代乳料对肉用犊牛生长性能、体尺指数及营养物质消化率的影响。选取20头新生黑安格斯犊牛,随机分为4组,每组5头。对照组随母牛饲喂,A、B、C组分别饲喂以葡萄糖、乳清粉和熟化玉米粉为主要糖源的代乳粉,30日龄时开始正式试验,试验期为45 d。分别在犊牛30、45、60、75日龄时进行空腹称重,测量体尺,每天观察记录犊牛的腹泻情况。在35~43和65~73日龄进行两期消化试验,采集样品,测定表观消化率。结果显示,试验前期不同糖源对各试验组犊牛影响明显,30~45日龄时C组平均日增重显著低于A、B组（P< 0.05）,并极显著低于对照组（P< 0.01）,A组日增重显著低于对照组和B组（P< 0.05）;C组DM表观消化率显著低于A、B组（P< 0.05）;CP表观消化率显著低于A组（P< 0.05）,极显著低于B组（P< 0.01）;犊牛腹泻率在这一时期也偏高。45日龄后这种影响逐渐减小,A、B组犊牛日增重开始增加,与对照组差异不显著（P> 0.05）,C组犊牛生长速度也快速增加,到75日龄时平均日增重与A组差异不显著（P> 0.05）;第二期消化试验中各试验组犊牛营养物质的表观消化率均明显提高,犊牛腹泻率也开始降低,试验后期降至为0。而在整个试验期不同糖源对各组的体尺及体尺指数影响不大。综上,在试验中乳糖效果最好,葡萄糖次之,熟化玉米粉则在前期效果不佳,但随着犊牛日龄的增加效果逐渐改善。     

不同诱食剂对安格斯犊牛生长性能、养分表观消化率及部分血清激素的影响

试验旨在研究日粮中添加不同诱食剂对安格斯犊牛生长性能、养分表观消化率及部分血清激素的影响。采用单因子随机区组设计,选用平均体重165.1 kg±35.5 kg、约6月龄的健康安格斯肉犊牛24头,随机分为A、B、C、D 4组,每组6个重复。A组为对照组,饲喂全混合日粮（TMR）;B、C、D组分别饲喂TMR+0.24%绿色素、TMR+1.2 g/d XTRACT^® 7065（香味剂）、TMR+0.4%甜蜜素。预饲期10 d,正饲期30 d。结果显示,与对照组相比,B、C、D组平均干物质采食量（ADMI）均显著提高（P < 0.05）。各诱食剂均能提高犊牛营养物质表观消化率,但各诱食剂的影响程度不同,其中B组酸性洗涤纤维（ADF）表观消化率显著高于其他诱食剂组（P < 0.05）,B组中性洗涤纤维（NDF）表观消化率显著高于对照组（P < 0.05）。在试验第31天采食后1 h,各组间神经肽Y（NPY）和5-羟色胺（5-HT）含量差异均不显著（P > 0.05）,B、D组NPY含量高于对照组,C组则低于对照组,B、D组5-HT含量均低于对照组,而C组则高于对照组。综合考虑,日粮中添加绿色剂、香味剂及甜味剂均可在一定程度上提高犊牛生长性能及营养物质消化率;绿色剂和甜味剂可以提高犊牛血清中NPY含量,而香味剂则使犊牛血清中5-HT含量升高。     

甘露寡糖添加方式对哺乳期犊牛生长性能、粪便菌群及血清免疫指标的影响

本试验旨在研究甘露寡糖的不同添加方式对哺乳期犊牛生长性能、粪便菌群及血清免疫指标的影响。试验选用日龄、体重相近,健康状况良好的新生荷斯坦公犊牛20头,随机分为4组,每组5个重复。Ⅰ组（对照组）不添加甘露寡糖;Ⅱ组在牛奶中添加5 g甘露寡糖;Ⅲ组在开食料中添加5 g甘露寡糖;Ⅳ组在牛奶和开食料中各添加2.5 g甘露寡糖。试验期56 d。结果表明：①在整个试验周期内,犊牛体长与体躯指数的组间差异不显著（P>0.05）。②整个试验周期内,各试验组犊牛平均干物质日采食量、平均日增重均高于Ⅰ组;各试验组料重比均低于Ⅰ组;且Ⅱ组试验效果优于其他两个试验组。③试验第21天时,各试验组犊牛粪便中双歧杆菌数均显著高于Ⅰ组（P<0.05）,且Ⅱ组显著高于其他两个试验组（P<0.05）;各试验组粪便中大肠杆菌数均显著低于Ⅰ组（P<0.05）,且以Ⅱ组为最低。试验第56天时,各试验组粪便双歧杆菌数均高于Ⅰ组,各试验组粪便中大肠杆菌数均低于Ⅰ组（P>0.05）,且Ⅱ组大肠杆菌数最低。④试验第21天时,Ⅱ组血清中IgA浓度显著高于Ⅰ组（P<0.05）,Ⅲ、Ⅳ组血清中IgA浓度略高于Ⅰ组（P>0.05）;IgG变化规律与IgA相似;Ⅳ组血清中IgM浓度显著高于Ⅰ组（P<0.05）,Ⅲ组在数值上略低于Ⅰ组（P>0.05）。试验第56天时,各试验组血清中免疫球蛋白含量均高于Ⅰ组（P>0.05）。综上所述,在犊牛饮用奶中添加甘露寡糖对于提高动物的生长性能及机体的抵抗力的效果优于其他两种方案。     

Effect of Different Addition Schemes of Mannan Oligosaccharide on Growth Performance,Fecal Microorganism and Serum Immune Indexes of Calves

This experiment was conducted to study the effects of mannan oligosaccharides with different adding schemes on growth performance, fecal microorganism and serum immune indexes of calves.Twenty newborn Holstein calves were randomly divided into 4 groups with 5 replicates per group.The claves in group Ⅰ（control group）were not fed the mannan oligosaccharide.The calves in group Ⅱ were fed 5 g mannan oligosaccharide added into the milk,and that of group Ⅲ were fed 5 g mannan oligosaccharide added into the starter diet while calves of group Ⅳ were fed 2.5 g mannan oligosaccharide added into the milk and the starter diet,respectively.The feeding trial lasted for 56 days.The results showed as follows:①During the whole experiment period,body length an body structure of calves had no significant difference between the groups（P>0.05).②During the whole experiment period,the average daily dry matter intake（ADMI）and average daily gain（ADG）in the experiment groups was higher than the control group,the F/G was lower than the control group,and group Ⅱ was the best of the three experiment groups.③On 21th day,the number of Bifidobacterium in feces of the calves in the group Ⅰ was significantly lower than that in other groups（P<0.05),and that of group Ⅱ was the highest;The number of E.coli in feces of the calves in the group Ⅰ was significantly higher than that in other groups（P<0.05),and the group Ⅱ was the lowest.On 56th day,the number of Bifidobacterium of experimental groups were higher than that of control group.The change of E.coli number of four groups were as the same as 21th day.④On 21th day,the serum IgA content of experimental groups were higher than group Ⅰ,and that of group Ⅱ were significantly increased（P<0.05);IgG had a similar change with the IgA;The serum IgM content of group Ⅳ was significantly higher than group Ⅰ（P<0.05), while that of group Ⅲ was lower than control group;On 56th day,the serum immune indexes of experimental groups were all higher than control group（P>0.05).In conclusion,adding mannan oligosaccharides could promote calf growth performance,gut health and immunity,while adding mannan oligosaccharide to milk had better effects.     

益生菌对断奶后犊牛生长性能及血清指标的影响

[目的]为探究益生菌对断奶后犊牛采食量、增重、胴体率和血液指标的影响。[方法]本试验选取了16 头（60±5）日龄荷斯坦奶公犊,随机分成4 组,分别为CK组（基础日粮+0%益生菌）、处理1组（基础日粮+1%益生菌）、处理2组（基础日粮+2%益生菌）、处理3组（基础日粮+3%益生菌）,预试期3 d,正式饲喂42 d。[结果]与CK组相比,处理1组、处理2组、处理3组的平均日采食量分别提高了6.05%、7.44%、7.91%（P>0.05）,平均日增重分别提高了7.11%、21.84%、21.24%（P<0.05）,胴体率分别提高了6.78%、9.75%、8.47%（P<0.05）,处理1组和CK组料重比差异不显著（P>0.05）,而处理2组、处理3组与CK组相比,料重比分别显著下降了11.84%和10.90%（P<0.05）,不同益生菌处理的断奶公犊牛血清中总蛋白、白蛋白、球蛋白含量均呈显著增加趋势（P<0.05）,但尿素氮、肌酐和尿酸指标差异不显著（P>0.05）。[结论]在断奶后公犊牛日粮中添加适量的益生菌,可以促进犊牛体重增加,刺激采食,提高免疫力,综合各个指标和饲喂成本,适宜的益生菌添加量为2%。     

不同净能水平的低蛋白日粮对猪生长性能和养分消化率的影响

选取120头22kg左右的杜×长×大三元杂交健康生长猪,随机分成5个处理,每个处理6个重复,每个重复4头,探讨低蛋白不同净能水平(10.54、10.28、9.96、9.63、9.45MJ/kg)日粮对生长猪生长性能和养分消化率的影响。结果表明:日粮蛋白降低4个百分点,不同净能处理间的采食量和饲料转化率没有显著差异(P>0.05),日增重随净能的下降呈线性增加,以9.45MJ/kg组最高(P<0.05);养分消化率中,除钙的消化率外,其余养分的消化率均随净能水平的增加而线性下降(P<0.05)。降低净能水平后,血清赖氨酸含量线性增加(P=0.03),对其余氨基酸影响差异不显著(P>0.05);对血清尿素氮含量的影响不显著(P>0.05)。由此可得出,低蛋白日粮中净能水平的降低并不影响生长猪的生长性能和养分消化率。     

复合矿物质舔砖对湖羊羔羊生长性能的影响试验

浙江各地的湖羊养殖,日粮多以粗饲料为主,精饲料所占比例很低,且无添加预混料的习惯,由此导致了因日粮矿物质缺乏而引起生长缓慢等亟待解决的问题。本试验采用复合矿物质舔砖形式补充湖羊日粮中的矿物质,这种方式不但操作方便、节省劳动力而且还利于湖羊的摄食和吸收,是一种较好的矿物质添加方式。现将试验结果报告如下。     

Cattle Grazing Distribution and Efficacy of Strategic Mineral Mix Placement in Tropical Brazilian Pastures

A study was conducted in Brazil to identify factors affecting grazing distribution of yearling Nelore cross heifers and to evaluate the efficacy of placement of a salt–mineral mix away from water to improve uniformity of grazing. Two pastures (25 ha and 42 ha) were evaluated for four 15-d sessions. Mineral mix was placed 590 m to 780 m from water during two sessions and at water for two sessions. Stubble heights were measured at the beginning and end of each session in 1-ha subunits of each pasture. Cattle locations were recorded on day 13 and 14 of each session by horseback observers. Heifers avoided areas with a preponderance of forbs and taller grass (P < 0.001). For the first 15 days of the study cattle avoided subunits farther from water. Thereafter, horizontal distance from water had no affect on grazing use (P > 0.10). Stubble height reduction was more uniform (P < 0.05) when the mineral mix was at water compared to away from water. In contrast, heifers spent less time farther from water when mineral mix was placed at water (P = 0.02) based on visual observations. Strategic placement of a salt–mineral mix away from water does not appear to be a reliable tool to improve cattle grazing distribution in humid tropical pastures from 25 ha to 45 ha in size.     

不同精粗比全混合日粮对湖羊生长性能、血清激素浓度和屠宰性能的影响

本试验旨在研究不同精粗比全混合日粮对湖羊生长性能、血清激素浓度和屠宰性能的影响。选择体重相近、体况良好且健康的湖羊羔羊40只,随机分为4组,每组10只(公母各占1/2)。4组试验羊分别饲喂精粗比为70∶30(试验Ⅰ组)、60∶40(试验Ⅱ组)、50∶50(试验Ⅲ组)和40∶60(试验Ⅳ组)的全混合日粮。试验期为70 d,其中预试期为14 d,正试期为56 d。结果显示:1)正试期第14天和第35天,试验Ⅰ组羔羊平均日增重(ADG)极显著高于试验Ⅲ和Ⅳ组(P<0.01);正试期第35天和第56天,试验Ⅱ组羔羊体重(BW)显著高于试验Ⅳ组(P<0.05)。2)正试期第14天,试验Ⅱ组羔羊体斜长以及试验Ⅰ组羔羊胸围和管围均显著高于试验Ⅳ组(P<0.05);正试期第35天,试验Ⅰ组羔羊胸围和管围均显著高于试验Ⅳ组(P<0.05),试验Ⅰ组羔羊血清瘦素(LEP)浓度显著高于试验Ⅱ组(P<0.05);正试期第56天,试验Ⅰ组羔羊血清生长激素(GH)和四碘甲状腺原氨酸(T4)浓度显著高于试验Ⅳ组(P<0.05),试验Ⅱ组羔羊血清三碘甲状腺原氨酸(T3)浓度显著高于试验Ⅲ和Ⅳ组(P<0.05)。3)试验Ⅱ组羔羊宰前活重、胴体重、屠宰率、后腿重和背膘厚均极显著高于试验Ⅳ组(P<0.01),试验Ⅱ组羔羊肋肉厚、心脏和肝脏重量均显著高于试验Ⅳ组(P<0.05)。综上所述,在本试验条件下,育肥湖羊饲喂精粗比为60∶40的全混合日粮可获得最佳的生长性能和屠宰性能。     

不同锰源与锰水平对肉仔鸡生产性能和组织矿物元素沉积的影响

为研究不同锰源与锰水平对肉仔鸡的生产性能与组织矿物元素沉积的影响,试验采用2×5完全随机试验设计,在玉米—豆粕型基础日粮(锰含量为37.66mg/kg)中添加0、45、90、130、180mg/kg(5个锰添加水平)的复合氨基酸锰和硫酸锰(2种锰源),构成10个日粮处理组,将540只1日龄健康艾维茵肉仔鸡随机分为10个处理组,开展肉仔鸡饲养试验(共42d)。于35日龄时测定其生产性能指标,计算料肉比;于42日龄时测定其胫骨、肝脏、肾脏组织中铜、铁、锌浓度以及胫骨灰分、钙及磷含量。结果表明,在上述日粮中,锰添加量在45~130mg/kg时,无论是添加复合氨基酸锰组还是添加硫酸锰组35日龄肉仔鸡体重和采食量较未添加组差异显著(P≤0.05),经分析,锰水平对其平均体重及采食量有极显著影响(P<0.01);不同锰源的35日龄肉仔鸡体重、采食量、料肉比差异不显著(P >0.05)。42日龄肉仔鸡胫骨、肝脏、肾脏组织中铜、锌、铁含量及胫骨灰分、钙磷含量未受锰源和锰水平及两者互作的显著影响(P >0.05)。由以上结果可以得出,锰水平对肉仔鸡生长性能有极显著影响(P<0.01);锰源对肉仔鸡生产性能无显著影响(P >0.05);锰源和锰水平及两者互作对肉仔鸡组织矿物元素沉积无显著影响(P >0.05)。     

Effect of High Concentrations of Cholecalciferol on Growth,Bone Mineralization,and Mineral Retention in Broiler Chicks Fed Suboptimal Concentrations of Calcium and Nonphytate Phosphorus

An experiment was conducted to examine the effects of supplementing high concentrations (200 vs. 1,200, 2,400, and 3,600 ICU/kg) of cholecalciferol (CC) on performance, bone mineralization, and mineral retention in broiler chickens (2 to 42 d of age) fed a basal diet containing suboptimal concentrations of Ca and nonphytate P (NPP; 0.5 and 0.25%, respectively). A reference diet (RD) containing recommended levels of Ca, NPP, and CC was considered as control. Each diet was fed ad libitum to 21 replicates containing 5 birds in each. Body weight gain, feed efficiency, tibia ash, and serum Ca and inorganic P decreased significantly (P < 0.05) in broilers fed suboptimal concentrations of Ca and NPP compared with those fed the RD. The BW gain (2,400 ICU/kg) and feed efficiency, leg abnormality score, and bone mineralization characteristics (3,600 ICU/kg) in broilers fed suboptimal concentrations of Ca and NPP with high concentrations of CC were similar to those fed the RD. The concentrations of Zn, Mn, Fe, and Cu in liver increased significantly (P < 0.05) with increase in concentrations of CC in the basal diet. Based on the results, it is concluded that performance and bone mineralization in broilers could be maintained with suboptimal concentrations of Ca and NPP (0.5 and 0.25%, respectively) and higher concentrations of CC (3,600 ICU/kg) in the diet.     

不同铜源对育成期乌苏里貉生长性能、营养物质消化率及血清生化指标的影响

本试验旨在研究不同铜源对育成期乌苏里貉生长性能、营养物质消化率及血清生化指标的影响。随机选取(60±5)日龄、健康的雄性乌苏里貉60只,随机分为4组,每组15个重复,每个重复1只。在基础饲粮中分别添加硫酸铜(Ⅰ组)、碱式氯化铜(Ⅱ组)、混合铜(Ⅲ组,碱式氯化铜和蛋氨酸铜,添加比例为1∶1,以铜元素计)和蛋氨酸铜(Ⅳ组),添加水平均为40 mg/kg。预试期7 d,正试期55 d。每组选取8只动物进行消化代谢试验。试验结束后,每只动物后肢静脉采血。结果表明:1)Ⅲ组的末重和平均日增重显著高于Ⅰ组(P<0.05),各组间料重比和平均日采食量差异不显著(P>0.05)。2)Ⅱ组的粗脂肪消化率显著高于Ⅰ、Ⅲ、Ⅳ组(P<0.05)。Ⅲ组的铜消化率显著高于Ⅰ、Ⅱ和Ⅲ组(P<0.05),干物质消化率、粗蛋白质消化率各组间差异不显著(P>0.05)。3)粪氮、尿氮含量及氮沉积各组间差异不显著(P>0.05)。Ⅰ、Ⅱ、Ⅳ组的粪铜含量显著高于Ⅲ组(P<0.05)。Ⅳ组尿铜含量显著高于Ⅰ、Ⅱ、Ⅲ组(P<0.05)。Ⅲ组的铜沉积显著高于Ⅰ、Ⅱ、Ⅳ组(P<0.05)。4)Ⅱ组血清中总蛋白含量显著高于Ⅲ、Ⅳ组(P<0.05)。Ⅲ、Ⅳ组血清尿素氮含量显著低于Ⅰ组(P<0.05),其余血清生化指标各组间差异不显著(P>0.05)。在本试验条件下,饲粮中混合添加适宜水平的碱式氯化铜和蛋氨酸铜,可提高育成期乌苏里貉生长性能、营养物质消化率、氮沉积和铜沉积,更有利于其生长发育。     

不同硒源及硒水平对大鼠生长性能、血清抗氧化能力和组织硒沉积的影响

本试验旨在考察不同硒源及硒水平对大鼠生长性能、血清抗氧化能力及组织硒沉积的影响,并以亚硒酸钠和商品酵母硒(酵母硒B)为参比,对本课题组用糖蜜和尿素为发酵底物研制的酵母硒(酵母硒A)生物学效价进行评定.将硒耗竭2周后的70只8周龄左右Wistar雌性大鼠称重,随机分到10个处理,每个处理7个重复,每个重复1只大鼠,分别饲喂不同处理的饲粮21d.处理1不添加任何形式的硒源,处理2～9在基础饲粮中分别以亚硒酸钠或酵母硒A的形式添加0.1、0.2、0.3和0.4mg/kg硒,处理10以酵母硒B形式添加0.3mg/kg硒.结果表明:1)不同硒源及硒水平对大鼠生长性能、血清谷胱甘肽过氧化物酶(GSH-Px)和超氧化物歧化酶活性影响不显著(P＞0.05);2)组织硒含量随饲粮硒水平的升高极显著增加(P＜0.01),添加酵母硒A组大鼠组织硒含量显著高于亚硒酸钠组(P＜0.05);3)以亚硒酸钠为参比,血清GSH-Px活性及肝脏、肾脏和肌肉硒含量作为判定指标,酵母硒A的相对生物学效价分别为95.9％、127.5％、114.5％和101.2％;4)添加酵母硒A和酵母硒B对大鼠生长性能、血清抗氧化能力的影响不显著(P＞0.05),但添加酵母硒A组大鼠肾脏硒含量极显著高于酵母硒B组(P＜0.01),而酵母硒B在肌肉中有更多的硒沉积(P＜0.01).结果提示:1)硒源对大鼠组织硒沉积有较大影响,酵母硒相对于亚硒酸钠具有更高的生物学效价,但不同酵母硒之间存在一定的差异;2)饲粮硒水平对大鼠血清抗氧化能力影响较小,以血清GSH-Px活性为衡量标准,0.1mg/kg硒的酵母硒和亚硒酸钠都能满足大鼠的需要,但更高水平的酵母硒可以使大鼠组织中有更多硒的储备.