饲粮精氨酸添加水平对冬毛期雌性蓝狐生产性能、营养物质消化率及氮代谢的影响

本试验旨在研究饲粮精氨酸添加水平对冬毛期雌性蓝狐生产性能、营养物质消化率及氮代谢的影响。选取120日龄、体重相近的60只健康雌性蓝狐,随机分为6组,每组10个重复,每个重复1只。各组饲粮精氨酸添加水平分别为0(对照组)、0.2%、0.4%、0.6%、0.8%和1.0%,预试期7 d,正试期80 d。结果表明:1)0.6%添加组蓝狐的平均日增重极显著高于其他各组(P0.01),体长和皮长较对照组分别提高了1.42%和1.26%(P0.05),料重比极显著低于对照组(P0.01);0.4%添加组蓝狐平均日采食量显著低于对照组(P0.05)。2)饲粮精氨酸添加水平极显著影响蓝狐脂肪消化率(P0.01),各组蓝狐脂肪消化率随着饲粮精氨酸添加水平的升高而提高;0.6%添加组干物质消化率极显著高于对照组和0.2%、0.4%添加组(P0.01),饲粮精氨酸添加水平对蓝狐蛋白质消化率和碳水化合物消化率无显著影响(P0.05)。3)0.4%添加组蓝狐食入氮显著低于除0.6%添加组外其他各组(P0.05);0.6%添加组粪氮和尿氮含量均最低,而氮沉积、净蛋白质利用率、蛋白质生物学价值和蛋白质效率比均最高。综合各项指标,冬毛期雌性蓝狐饲粮中添加0.6%精氨酸(饲粮总精氨酸水平为2.04%)可提高平均日增重,降低料重比。     

低蛋白质日粮中添加赖氨酸和蛋氨酸对生长前期蓝狐消化代谢及生产性能的影响

本试验旨在探讨降低日粮中蛋白质水平同时补充适当的限制性氨基酸对生长前期蓝狐消化代谢及生产性能的影响.随机选取75只8周龄健康公蓝狐,随机分成5组,每组15个重复,每个重复1只蓝狐.对照组日粮蛋白质水平为28.7%,试验组日粮初始蛋白质水平分别为27.4%(Ⅰ组)、24.5%(Ⅱ组)、23.2%(Ⅲ组)和22.4%(Ⅳ组),然后分别加入相应量的赖氨酸和蛋氨酸,使其水平与对照组相当.结果表明:与对照组相比,当日粮中蛋白质水平降到27.4%并加入相应量的赖氨酸和蛋氨酸,其终体重、日增重、氮沉积极显著升高(P<0.01),例料转化率、氮沉积率和氮生物学效价显著升高(P<0.05);当日粮中蛋白质水平降到23.2%并加入相应量的赖氨酸和蛋氨酸,蓝狐的消化代谢及生长性能的各项指标均差异不显著(P>0.05).综合各项试验指标,蓝狐生长前期日粮蛋白质水平降低1.0～1.5个百分点并添加相应量的赖氨酸和蛋氨酸,可显著提高监狐消化率、代谢率和生产性能;降低2.0～4.0个百分点并添加相应的赖氨酸和蛋氨酸,对蓝狐消化代谢及生产性能无显著影响;此外,添加限制性氨基酸的低蛋白质日粮降低了蓝狐的饲养成本,减少了氮排泄量.     

饲粮赖氨酸和蛋氨酸水平对冬毛生长期银狐生长性能、营养物质消化率、血清生化指标及毛皮性状的影响

本试验旨在研究饲粮赖氨酸和蛋氨酸水平对冬毛生长期银狐生长性能、营养物质消化率、血清生化指标及毛皮性状的影响。选取70只120日龄、平均体重为(5 973±94)g的健康雄性银狐,随机分成7组,每组10个重复,每个重复1只银狐。采用二因子试验设计,赖氨酸添加水平分别为0、0.50%,蛋氨酸添加水平分别为0、0.25%、0.50%、0.75%,基础饲粮中赖氨酸含量为1.15%,蛋氨酸含量为0.66%。试验期51 d。结果表明:1)饲粮赖氨酸和蛋氨酸水平对冬毛期银狐生长性能无显著影响(P>0.05)。2)饲粮赖氨酸和蛋氨酸交互作用对营养物质采食量、排出量及消化率无显著影响(P>0.05);饲粮赖氨酸水平对营养物质采食量、蛋白质排出量及蛋白质消化率无显著影响(P>0.05),对干物质排出量、干物质消化率、脂肪排出量及脂肪消化率产生显著或极显著影响(P<0.05或P<0.01);饲粮蛋氨酸水平仅对干物质排出量产生显著影响(P<0.05)。3)饲粮赖氨酸和蛋氨酸交互作用对血清总氨基酸含量产生极显著影响(P<0.01),对血清总蛋白、白蛋白、尿素氮含量及丙氨酸氨基转移酶、天门冬氨酸氨基转移酶活性无显著影响(P>0.05);饲粮赖氨酸水平对血清总氨基酸含量产生极显著影响(P<0.01);饲粮赖氨酸水平对血清天门冬氨酸氨基转移酶活性产生极显著影响(P<0.01)。4)饲粮赖氨酸和蛋氨酸交互作用对毛皮性状影响不显著(P>0.05);饲粮赖氨酸或蛋氨酸水平对毛皮性状无显著影响(P>0.05)。从降低饲养成本和减少排放角度考虑,冬毛期银狐在基础饲粮中添加0.50%赖氨酸(实际含量1.65%)和0.25%蛋氨酸(实际含量0.91%)对银狐生产有利。     

饲粮蛋氨酸添加水平对断奶至3月龄獭兔生长性能、免疫功能及血清生化指标的影响

本文旨在探讨饲粮蛋氨酸添加水平对断奶至3月龄獭兔生长性能、免疫功能及血清生化指标的影响。选用30日龄断奶生长獭兔200只,随机分成5组,每组40个重复,每个重复1只兔。各组分别饲喂在基础饲粮中添加不同水平(0、0.15%、0.30%、0.45%、0.60%)蛋氨酸的试验饲粮。预试期7 d,正试期53 d。结果表明:1)饲粮蛋氨酸添加水平对平均日采食量影响不显著(P>0.05);对平均日增重影响显著(P<0.05),在0.45%添加组时达到最大值16.76 g/d;对料重比影响极显著(P<0.01),在0.45%添加组时达到最小值3.55。2)饲粮蛋氨酸添加水平对摄入氮、粪氮、尿氮、可消化氮、沉积氮、氮表观消化率、氮利用率和氮生物利用率均无显著影响(P>0.05)。3)饲粮蛋氨酸添加水平对血清免疫球蛋白A、免疫球蛋白G和免疫球蛋白M含量均无显著影响(P>0.05)。4)饲粮蛋氨酸添加水平对血清总蛋白、白蛋白、甘油三酯含量及碱性磷酸酶活性均无显著影响(P>0.05),但极显著影响血清尿素氮含量(P<0.01),其中0.30%和0.45%添加组极显著低于0和0.15%添加组(P<0.01),在0.45%添加组时达到最小值5.70 mmol/L。综合考虑本试验所测指标,断奶至3月龄獭兔的蛋氨酸适宜添加水平为0.45%(饲粮总蛋氨酸水平为0.68%)。     

日粮中添加蛋氨酸和赖氨酸对奶牛乳产量和氮素利用的影响

试验研究了代谢蛋白质中赖氨酸和蛋氨酸含量对中国荷斯坦奶牛泌乳性能和氮素利用的影响。对照组日粮能量充足但代谢蛋白质轻微受限。代谢蛋白质中蛋氨酸和赖氨酸的浓度分别为1.87%和5.93%,处理组如下(可代谢蛋白质中蛋氨酸和赖氨酸的百分数):L=以干物质计,对照日粮中添加0.49%的L-蛋氨酸盐酸盐(蛋氨酸,1.87;赖氨酸,7.00);M=对照日粮添加0.15%的2-羟基-4-甲硫基-丁酸(HMB)(蛋氨酸2.35;赖氨酸5.93);ML=对照组日粮同时添加0.49%赖氨酸盐酸盐和0.15%的2-羟基-4-甲硫基-丁酸(蛋氨酸2.39;赖氨酸7.10)。以上日粮用于饲喂60头泌乳中期奶牛,连续饲喂8周。单独添加赖氨酸(1.5 kg/d)或蛋氨酸(2.0 kg/d)可提高牛乳产量,且同时添加2种氨基酸可进一步提高牛乳产量(3.8 kg/d)。不同处理组奶牛采食量差异不显著。与对照组和饲喂L日粮组奶牛相比,饲喂M和ML组日粮的奶牛乳脂肪含量较高,但乳蛋白、乳糖和体细胞数各处理组差异不显著。添加蛋氨酸或赖氨酸可显著提高动脉血浆中蛋氨酸和赖氨酸浓度。饲喂ML日粮奶牛摄入氮向乳氮的转化率高于对照组,而血清、尿液和乳中尿氮浓度低于对照组。饲喂可代谢蛋白质轻微受限的日粮时,添加HMB和L-蛋氨酸盐酸盐以提供2.3%蛋氨酸和7.0%赖氨酸提高了乳产量、乳蛋白产量和氮素利用率。     

低蛋白质饲粮中添加蛋氨酸对育成期蓝狐生长性能和营养物质消化代谢的影响

本试验旨在研究低蛋白质饲粮中添加蛋氨酸对育成期蓝狐生长性能、营养物质消化代谢的影响。选用平均体重为(2.21±0.60)kg的9周龄健康雄性蓝狐105只,随机分为7组,每组15个重复,每个重复1只。6个试验组分别饲喂在蛋白质水平为30%的基础饲粮(低蛋白质饲粮)中添加0(Ⅰ组)、0.2%(Ⅱ组)、0.4%(Ⅲ组)、0.6%(Ⅳ组)、0.8%(Ⅴ组)和1.0%(Ⅵ组)蛋氨酸的试验试粮。对照组(Ⅶ组)饲喂蛋白质水平为32%的基础饲粮(适宜蛋白质饲粮)。预试期7 d,正试期45 d。结果表明:Ⅴ组与Ⅵ组的末重(第45天体重)极显著高于其他试验组(P<0.01),并与对照组差异不显著(P>0.05)。第16~30天的平均日增重,Ⅳ组、Ⅴ组、Ⅵ组显著高于Ⅰ组(P<0.05),并与对照组差异不显著(P>0.05);第31~45天的平均日增重,Ⅴ组、Ⅵ组极显著高于其他试验组(P<0.01),且Ⅴ组还显著高于Ⅵ组和对照组(P<0.05)。Ⅴ组、Ⅵ组的干物质排出量极显著低于其他试验组(P<0.01),并与对照组差异不显著(P>0.05);Ⅴ组的干物质消化率显著高于Ⅰ组、Ⅲ组和Ⅳ组(P<0.05),并与对照组差异不显著(P>0.05);Ⅴ组、Ⅵ组的蛋白质消化率显著高于Ⅰ组、Ⅱ组和Ⅲ组(P<0.05),并与对照组差异不显著(P>0.05);Ⅰ组的脂肪消化率显著低于其他各组(P<0.05),其他各组间差异不显著(P>0.05)。Ⅴ组和Ⅵ组的胱氨酸排出量极显著低于Ⅱ组、Ⅲ组和对照组(P<0.01);Ⅵ组的胱氨酸消化率极显著高于其他各组(P<0.01),对照组的胱氨酸消化率与Ⅴ组无显著差异(P>0.05);随着蛋氨酸添加水平的提高,蓝狐的蛋氨酸消化率相应增高,Ⅵ组显著或极显著高于其他各组(P<0.05或P<0.01),Ⅴ组与对照组差异不显著(P>0.05)。Ⅳ组的总氮排出量显著低于Ⅰ组、Ⅱ组和Ⅲ组(P<0.05),其他各组间无显著差异(P>0.05);Ⅴ组的氮沉积极显著高于其他各组(P<0.01),其他各组间无显著差异(P>0.05);Ⅰ组的净蛋白质利用率显著低于其他各组(P<0.05),其他各组间无显著差异(P>0.05)。综合本试验的各项测定指标,在蛋白质水平为30%的低蛋白质饲粮中添加0.8%的蛋氨酸即饲粮中蛋氨酸水平为1.14%时能够满足育成期蓝狐对蛋氨酸的需要量,此时蓝狐的生长性能、蛋白质消化率和氮沉积较为理想。     

饲粮玉米油与棕榈酸配比对冬毛期蓝狐生产性能、营养物质消化率及氮代谢的影响

本试验旨在研究饲粮玉米油与棕榈酸配比对冬毛期蓝狐生产性能、营养物质消化率及氮代谢的影响。选取120日龄体重相近的健康雄性蓝狐60只,随机分成6组,每组10个重复,每个重复1只蓝狐。各组分别饲喂玉米油与棕榈酸配比为0∶12(Ⅰ组)、3∶9(Ⅱ组)、5∶7(Ⅲ组)、7∶5(Ⅳ组)、9∶3(Ⅴ组)和12∶0(Ⅵ组)的试验饲粮。预试期7 d,正试期67 d。结果表明:1)饲粮玉米油与棕榈酸配比对冬毛期蓝狐平均日增重有极显著影响(P0.01),对平均日采食量和料重比无显著影响(P0.05)。随着饲粮玉米油添加比例的升高,平均日增重逐渐升高。饲粮玉米油与棕榈酸配比对冬毛期蓝狐体长、针毛长度和绒毛长度均无显著影响(P0.05),Ⅵ组鲜皮长显著高于Ⅰ组(P0.05)。2)饲粮玉米油与棕榈酸配比对冬毛期蓝狐脂肪、碳水化合物和干物质消化率有极显著影响(P0.01),对蛋白质消化率无显著影响(P0.05)。3)饲粮玉米油与棕榈酸配比对冬毛期蓝狐食入氮、粪氮、尿氮、氮沉积、净蛋白利用率和蛋白质生物学价值均无显著影响(P0.05)。然而,氮沉积随饲粮中玉米油添加比例的升高呈上升趋势,Ⅰ组最低,Ⅵ组最高;净蛋白质利用率和蛋白质生物学价值均以Ⅴ组最高。综合各指标,从保证蓝狐生产性能和营养物质消化率考虑,冬毛期蓝狐干饲粮中玉米油与棕榈酸的适宜比例应当维持在9∶3(即亚油酸含量为3.76%)。     

不同蛋氨酸和赖氨酸添加水平对五龙鹅生产性能的影响

试验选用 4 2日龄健康五龙鹅 ,研究了饲粮中不同蛋氨酸和赖氨酸水平对五龙鹅育成期生产性能的影响。试验采用 3× 3二因子设计 ,饲粮中蛋氨酸和赖氨酸添加水平均为 0 .1%、0 .2 %和 0 .3%三个水平。结果表明 :当饲粮中蛋氨酸含量为 0 .33% ,赖氨酸含量为 0 .70 %时 ,鹅的生产性能和饲料利用率最好。     

蛋氨酸对梅花鹿仔鹿生长性能及血清生化指标的影响

本试验旨在研究在低蛋白质饲粮中添加蛋氨酸对梅花鹿仔鹿生长性能及血清生化指标的影响。选取24头健康的梅花鹿仔鹿,随机分成3组(Ⅰ、Ⅱ、Ⅲ组),每组8个重复,每个重复1只。Ⅰ组饲喂蛋白质水平为14.16%的饲粮,Ⅱ组饲喂添加了0.16%蛋氨酸的蛋白质水平为12.46%的低蛋白质饲粮,Ⅲ组饲喂添加了0.12%蛋氨酸的蛋白质水平为12.46%的低蛋白质饲粮。饲养试验于2015年10月2日开始,至2015年10月24日结束。为了测定其生长性能,在试验开始和结束时对仔鹿进行称重;为了测定其血清生化指标,在试验结束时进行采血。结果表明:各组梅花鹿仔鹿的增重、平均日增重、料重比均差异不显著(P0.05);各组梅花鹿仔鹿血清中总蛋白(TP)、球蛋白(GLOB)、尿素氮(UN)、葡萄糖(GLU)含量及丙氨酸氨基转移酶(ALT)、天冬门氨酸氨基转移酶(AST)、碱性磷酸酶(AKP)活性均差异不显著(P0.05);Ⅲ组血清中白蛋白(ALB)含量显著高于Ⅰ组(P0.05)。由此得出,与蛋白质水平为14.16%的饲粮相比,在蛋白质水平为12.46%的低蛋白质饲粮中添加0.16%蛋氨酸对梅花鹿仔鹿的生长性能及血清生化指标均无显著影响,说明在本试验范围内利用低蛋白质饲粮添加蛋氨酸代替高蛋白质饲粮是可行的。     

饲粮铜、锌添加水平对育成期蓝狐生长性能、营养物质消化率及氮代谢的影响

本试验旨在研究饲粮铜、锌添加水平对育成期蓝狐生长性能、营养物质利用率及氮代谢的影响.试验采用2×3完全随机试验设计,分别在基础饲粮中添加2个水平的锌(40和120 mg/kg)和3个水平的铜(30、45和60 mg/kg),另设对照组(添加0 mg/kg铜和40 mg/kg锌).选用(55±5)日龄、体重相近的健康雄性蓝狐84只,随机分成7组,每组12个重复,每个重复1只.预试期为7d,正试期为75 d.结果表明:1)饲粮中添加铜有提高蓝狐平均日增重(P=0.06)和降低料重比(P=0.08)的趋势,但并未观测到铜、锌之间的互作效应(P＞0.05).30 mg/kg铜+40 mg/kg锌和45 mg/kg铜+120 mg/kg锌组平均日增重显著高于对照组(P＜0.05),料重比显著低于对照组(P＜0.05).2)饲粮中添加铜能极显著提高蓝狐蛋白质和脂肪消化率(P＜0.01).60mg/kg铜+40mg/kg锌和60mg/kg铜+120mg/kg锌组蓝狐蛋白质消化率极显著高于对照组(P＜0.01),45 mg/kg铜+120 mg/kg锌组显著高于对照组(P＜0.05).30 mg/kg铜+40 mg/kg锌、45 mg/kg铜+40 mg/kg锌、30 mg/kg铜+120 mg/kg锌、60 mg/kg铜+120 mg/kg锌组蓝狐脂肪消化率极显著高于对照组(P＜0.01),45 mg/kg铜+120mg/kg锌组显著高于对照组(P＜0.05).饲粮铜、锌添加水平对粪便中铜排出量有极显著影响(P＜0.01);饲粮锌添加水平对粪便中锌排出量有极显著影响(P＜0.01).各组蓝狐铜排出量和锌排出量并未观测到铜、锌之间的互作效应(P＞0.05).3)饲粮中添加铜极显著降低了粪氮含量(P＜0.01),饲粮铜、锌添加水平并未对各组蓝狐食入氮、尿氮、氮沉积含量及蛋白质生物学价值、净蛋白质利用率产生显著影响(P＞0.05).综合试验结果得出,育成期蓝狐饲粮中添加30 mg/kg铜+40mg/kg锌(总铜、总锌水平为别37.68和80.08 mg/kg)时可提高蓝狐的生长性能和营养物质消化率,同时降低了粪便中氮的排放.     

Effects of diets with different protein and DL-methionine levels on the growth performance and N-balance of growing minks

This study was performed to evaluate the effects of diets with different protein and dl-methionine (Met) levels on nitrogen (N) retention, nutrient digestibility, growth performance, and some blood parameters in growing minks. Eighty healthy male minks were selected and randomly divided into five groups with different types of diet. The dietary protein levels, expressed as percentage of dry matter (DM), were 36% (HP) and 28% (LP), corresponding to average 363g and 295g protein/kg DM, respectively. LP was supplemented with Met (0.3%, 0.6% and 0.9% DM); the codes were LP+M1, LP+M2 and LP+M3, respectively. From July to middle of September, the average daily gain and feed: gain ratio (F/G) of the minks that received the diet with 0.6% Met added to the low protein diet was better than feeding HP and other groups. Fecal N and Urinary N of group LP+M2 were the lowest one, in contrast, the daily retention of N was the highest one. Digestibility of DM and CP were not affected by different diets, but digestibility of fat declined with dietary protein level decreasing. Serum urea nitrogen (SUN) was affected by different protein and Met levels. Considering all factors the best performance could be observed offering LP+M2, the prime level of Met was 13.87 g/kg DM in dietary, and 258.5 g digestible protein kg(-1) DM was enough for mink in growing period. Furthermore, addition of Met in low protein diets for minks would be beneficial in terms of reduced feed expenses and lower nitrogen emissions to the environment.     

Isoleucine and valine supplementation of a low-protein corn-wheat-soybean meal-based diet for piglets: growth performance and nitrogen balance

The effects of Ile and Val supplementation of a low-CP, corn-wheat-soybean meal-based piglet diet on growth performance, incidence of diarrhea, and N balance were studied using 60 Landrace x Duroc male piglets in a 4-wk experiment. The 60 individually caged piglets were divided into 5 dietary treatments, each consisting of 12 piglets. Diet 1 was a positive control diet (20% CP); diet 2 was a low-CP negative control diet (17% CP); diets 3, 4, and 5 were low-CP diets to which Ile, Val, or the combination of Ile and Val were added, respectively. All diets were supplemented with Lys, Met, Thr, and Trp to provide the required concentrations of these AA according to the 1998 NRC. Average daily gain and ADFI were similar among pigs fed the positive control, Val-added, and the Val plus Ile-added diets. On wk-2 and wk-4, fecal score was greater (softer feces) in piglets fed the 20% CP level compared with the remaining treatments (P < 0.01). Nitrogen intake was decreased (P < 0.0001) in pigs fed diets containing low levels of CP compared with pigs fed the 20% CP diet. Fecal N excretion (g/d) was decreased (P < 0.05) in piglets fed low-CP diets at wk 1 and wk 4 of feeding, and in urine at wk 4 of feeding. Crude protein levels or AA supplementation had no effect on N retention efficiencies. These results indicate that the supplementation of Val alone, or in combination with Ile, to a low-CP piglet diet with adequate levels of Lys, Met, Thr, and Trp is necessary to achieve maximum performance in pigs consuming corn-wheat-soybean meal-based diets.     

Nitrogen balance in barrows fed low-protein diets supplemented with essential amino acids

This study was conducted to determine the effect of addition of essential amino acids (EAA) to low-protein diets on N balance in barrows. Thirty barrows (Duroc × Yorkshire) with an initial BW of 36 kg were fed 5 corn- and soybean meal-based diets containing 13.6 to 18.2% crude protein (CP) for 10 d in a randomized complete block design. The 18.2% CP diet was formulated without addition of EAA (Lys, Met or Thr). The other diets contained 13.6 to 16.5% CP and were supplemented with EAA to provide 0.83% true digestible lysine equal to that in the 18.2% CP diet. Fecal, urinary, and total N excretion as well as N retention (g/d) decreased with decreasing dietary CP level (P < 0.01). The apparent digestibility of N was almost the same for the 18.2 and 16.5 CP diets, but the value was 2% higher (P = 0.07) than that for the 13.6% CP diet. These findings indicate that, compared with the 18.2% CP diets, supplementation with three EAA to the lowest-protein diets (13.6 CP) is inadequate for maximum intestinal protein digestion, amino acid absorption, or tissue protein deposition in growing barrows.     

Effects of rumen-protected methionine and lysine on ruminant performance and nutrient metabolism

Four trials were conducted to determine the effects of supplemental rumen-protected methionine (RPMet) and lysine (RPLys) on lamb N metabolism and steer feedlot performance. In trial 1, 20 Suffolk-sired, crossbred lambs (avg weight 32 kg) were fed diets containing no supplemental methionine (Met) and lysine (Lys), .03% RPMet, .05% RPLys or .03% RPMet + .05% RPLys. Lambs fed .03% RPMet + .05% RPLys had a 33% increase in N retention compared with lambs fed no supplemental Met and Lys. In trial 2, to verify the protection and availability of these amino acids, five Targhee lambs (avg weight 35 kg) were fed corn-soybran flake diets supplemented with urea and were assigned in a 5 X 5 Latin square to one of the following treatments: 1) control; 2) .03% RPMet + .05% RPLys offered in the diet; 3) .03% RPMet + .05% RPLys abomassally infused; 4) .03% non-protected Met + .05% non-protected Lys offered in the diet and 5) .03% Met + .05% Lys abomasally infused. Treatments 2, 3 and 5 decreased (P less than .05) urinary N (g/d) and increased N retention (P less than .05) compared with the control diet (treatment 1). Increases (P less than .05) in plasma Met and Lys concentrations indicated that the amino acids were protected and available for animals at the site of absorption. In trial 3, 40 crossbred Angus steers (avg weight 247 kg) were fed diets composed of 53% corn silage and 47% concentrate and supplemented with soybean meal to 11.3% crude protein. Steers that were fed diets containing .19% RPMet + .11% RPLys had greater daily gain (P less than .05) than those fed diets containing no supplemental amino acids, .11% RPMet + .01% RPLys, and .15% RPMet + .06% RPLys (1.39 vs 1.23, 1.22 and 1.20 kg/d, respectively). Similar improvements in feed conversion resulted and increases in plasma Met concentrations followed the same trend. In trial 4, 40 crossbred Angus steers (avg weight 368 kg) were fed corn grain-corn silage diets supplemented with urea. Treatments were: no supplemental amino acids; .05% RPMet + .01% RPLys; .10% RPMet + .04% RPLys; and .15% RPMet + .07% RPLys. No differences in steer performance resulted due to supplemental RPMet and RPLys (P greater than .05). The results of these trials suggest that the RPMet and RPLys used in this study are protected from ruminal degradation, are available post-ruminally and can improve lamb N balance and growing steer performance.     

饲粮铜水平对冬毛期雌性蓝狐生长性能、营养物质消化率、血清生化指标及毛皮品质的影响

本试验旨在研究饲粮铜水平对冬毛期雌性蓝狐生长性能、营养物质消化率、血清生化指标及毛皮品质的影响。试验选取115日龄左右的健康雌性蓝狐50只,随机分成5组,每组10个重复,每个重复1只。以五水硫酸铜(Cu SO_4·5H_2O)为铜源,在基础饲粮中分别添加0、12.22、32.22、72.22、152.22 mg/kg的铜配成5种试验饲粮,5种试验饲粮铜水平分别为7.78(Ⅰ组,作为对照组)、20(Ⅱ组)、40(Ⅲ组)、80(Ⅳ组)、160 mg/kg(Ⅴ组)。预试期为7 d,正试期为60 d。结果表明:1)Ⅲ、Ⅳ和Ⅴ组蓝狐的平均日增重显著高于对照组(P0.05),料重比显著低于对照组(P0.05);各组蓝狐的终末体重及平均日采食量差异不显著(P0.05)。2)各组蓝狐的干物质消化率、蛋白质消化率及氮沉积差异不显著(P0.05);Ⅲ、Ⅳ组蓝狐的脂肪消化率显著高于对照组(P0.05),其他各组间差异不显著(P0.05);铜排出量随着饲粮铜水平的升高极显著的增加(P0.01)。3)Ⅴ组蓝狐血清总蛋白和白蛋白含量显著高于对照组和Ⅱ组(P0.05);Ⅴ组蓝狐血清尿素氮含量显著高于Ⅱ组(P0.05);各组蓝狐血清铜蓝蛋白活性差异不显著(P0.05),Ⅳ组蓝狐血清铜锌超氧化物歧化酶活性显著高于对照组及Ⅱ和Ⅲ组(P0.05)。4)Ⅴ组蓝狐肝脏铜含量显著高于对照组(P0.05),血清铜、锌、铁含量各组间差异不显著(P0.05)。5)饲粮铜水平并未显著影响蓝狐的体长和干皮长(P0.05);Ⅲ和Ⅴ组蓝狐针毛长和绒毛长显著大于Ⅱ和Ⅳ组(P0.05);Ⅴ组蓝狐皮张颜色显著深于对照组(P0.05)。由此可见,在饲粮中添加32.22 mg/kg铜即铜水平为40.00 mg/kg时,冬毛期雌性蓝狐可获得较好的生长性能、营养物质消化率及毛皮品质,同时铜的排放量较低。     

0～21和22～42日龄黄羽肉鸡可消化蛋氨酸需要量的研究

试验一和试验二分别选用1日龄和22日龄岭南黄鸡各2 000只和1 600只,按性别和体重分成10处理组(公、母鸡各5组),每组4重复栏,每栏50(试验一)和40只鸡(试验二)。2个试验均采用5(饲粮蛋氨酸水平)×2(性别)两因子试验设计,试验一和二分别设0.35%、0.40%、0.45%、0.50%和0.55%以及0.30%、0.35%、0.40%、0.45%和0.50%5个饲粮蛋氨酸水平。结果表明:随着饲粮蛋氨酸水平提高,0～21日龄和22～42日龄公、母鸡每日总蛋氨酸摄入量和真可消化蛋氨酸摄入量呈线性或二次曲线升高(P<0.05);0～21日龄公、母鸡的日增重呈二次曲线升高(P<0.05),0～21日龄和22～42日龄公、母鸡的饲料增重比呈二次曲线降低(P<0.05或0.1)。可见,在基础饲粮中添加适量蛋氨酸改善了黄羽肉鸡的生产性能。根据二次回归模型估测黄羽肉鸡获得最佳生产性能95%处的总蛋氨酸需要量和真可消化蛋氨酸需要量,0~21日龄母鸡为0.433%~0.435%和0.404%~0.406%,公鸡为0.445%~0.454%和0.416%~0.425%,22～42日龄母鸡为0.463%和0.437%,公鸡为0.375%和0.349%。     

Performance and nutrient balance in growing swine fed low-protein diets supplemented with amino acids and potassium

Five experiments, using 216 barrows and gilts (initial weight 19.9 to 23.7 kg), were conducted to evaluate the effects of improving amino acid balance by supplementing low-protein corn-soybean meal diets with essential amino acids. Three experiments were growth studies lasting approximately 3 wk, and the other two were 4-d metabolism trials. The control diets in each of the experiments were formulated to contain .80% lysine and contained approximately 17% CP. The other diets were formulated from a basal diet containing a 10.9% CP, fortified corn-soybean meal mixture, which included crystalline L-lysine.HCI, L-tryptophan, L-threonine, L-isoleucine, DL-methionine and L-valine to correct amino acid deficiencies. Nonessential N (glutamic acid or urea) also was added to some of the diets to increase the CP equivalent to 12 or 13%. Supplemental K (as a salt of bicarbonate or glutamate) was included in selected diets to increase the K concentration to the same level as that of the control diet. Growth rate of pigs fed the basal diet was similar (P greater than .05) to that of the control diets in only one growth study. Added glutamic acid and urea did not improve either growth rate or N retention. Added K improved K digestibility but did not increase K retention, N retention or growth rate. Improving amino acid balance by adding essential amino acids to low-protein diets did not benefit performance beyond that of a typical corn-soybean meal diet. Under our conditions, K, N, and nonessential N were not limiting.     

不同水平脂肪对冬毛期蓝狐生产性能及消化代谢的影响

采用单因素随机试验设计,选择冬毛期蓝狐72只,随机分成4组(Ⅰ、Ⅱ、Ⅲ、Ⅳ组),公母各半,分别饲喂在基础日粮中添加1%、4%、7%和10%豆油的4种试验饲粮,以探讨不同水平脂肪对冬毛期蓝狐生产性能和消化代谢的影响。结果表明:不同水平脂肪对日采食量和干物质消化率影响差异不显著(P>0.05);Ⅱ组的日增重高于其他组,Ⅱ组公狐的日增重显著高于Ⅲ组(P<0.05);Ⅱ组的料肉比低于其他组,其中Ⅱ组母狐的料肉比显著低于其他组(P<0.05)。公狐Ⅱ组的日食入氮显著高于Ⅰ组(P<0.05);日粪氮排出量各组间差异不显著(P>0.05);Ⅳ组公狐和母狐的日尿氮排出量分别显著(P<0.05)和极显著(P<0.01)高于其他组;Ⅱ组的日沉积氮、氮沉积率、氮表观消化率和氮生物学效价高于其他组,并且日沉积氮、氮沉积率和氮生物学效价显著(P<0.05)或者极显著(P<0.01)高于Ⅳ组。随着脂肪添加量的增加,蓝狐的食入脂肪量、脂肪消化率和可消化脂肪量也随之增加,达到了显著(P<0.05)或者极显著(P<0.01)的差异。母狐Ⅰ组的总胆固醇极显著地低于Ⅱ组和Ⅲ组(P<0.01);甘油三酯以Ⅲ组最低,公狐Ⅲ组的甘油三酯显著低于Ⅰ组和Ⅳ组(P<0.05),母狐Ⅲ组极显著低于其他组(P<0.01);对高密度脂蛋白胆固醇无影响(P>0.05);随着脂肪水平的提高,血清总蛋白呈现先升后降,公狐以Ⅱ组最高,Ⅰ组最低,两组之间差异极显著(P<0.01)。不同水平脂肪对冬毛期蓝狐的体长、干皮长、针毛长度和针毛直径的影响差异不显著(P>0.05),母狐Ⅱ组的绒毛长度极显著地高于Ⅳ组(P<0.01),公狐Ⅰ组的绒毛直径显著地高于Ⅲ组(P<0.05)。综合各项试验指标,冬毛期蓝狐日粮中添加4%的豆油效果较好。