12月龄伊犁马对维生素B1和维生素B2的需要量

本试验旨在研究维生素B1、维生素B2不同摄入量对12月龄伊犁马血液、尿液相关指标的影响,以得到12月龄伊犁马对维生素B1、维生素B2的需要量。试验选取12月龄±5日龄、平均体重(245.28±18.36)kg的伊犁马公马35匹,随机分为5组,每组7匹,分别为试验Ⅰ组、试验Ⅱ组、试验Ⅲ组、试验Ⅳ组、试验Ⅴ组,马匹饲喂相同的基础饲粮,并分别添加0、16、32、48和64 mg/(匹·d)的维生素B1和0、10、20、30和40 mg/(匹·d)的维生素B2,进行为期20 d的饲养试验。试验Ⅰ组、试验Ⅱ组、试验Ⅲ组、试验Ⅳ组、试验Ⅴ组实际摄入维生素B1量分别为19.00、33.49、48.27、62.96、77.53 mg/(匹·d),实际摄入维生素B2量分别为21.95、31.68、41.77、51.53、61.26 mg/(匹·d)。结果表明:随着实际摄入维生素B1量的增加,伊犁马血浆维生素B1含量、红细胞转酮酶活性(E-TKA)、尿液维生素B1排出量逐渐升高,焦磷酸硫胺素(TPP)效应逐渐降低。试验Ⅰ组血浆维生素B1含量显著低于试验Ⅲ组(P0.05),极显著低于试验Ⅳ组、试验Ⅴ组(P0.01);试验Ⅰ组E-TKA极显著低于试验Ⅲ组、试验Ⅳ组和试验Ⅴ组(P0.01);试验Ⅰ组TPP效应显著高于试验Ⅲ组(P0.05),极显著高于试验Ⅳ组、试验Ⅴ组(P0.01);试验Ⅰ组尿液维生素B1排出量极显著低于试验Ⅲ组、试验Ⅳ组、试验Ⅴ组(P0.01)。随着实际摄入维生素B2量的增加,伊犁马血浆维生素B2含量出现波动变化,红细胞谷胱甘肽还原酶活性系数(E-GRAC)逐渐降低,尿液维生素B2排出量逐渐增加。试验Ⅰ组血浆维生素B2含量显著低于试验Ⅲ组、试验Ⅳ组(P0.05),极显著低于试验Ⅱ组、试验Ⅴ组(P0.01);试验Ⅰ组E-GRAC极显著高于试验Ⅱ组、试验Ⅲ组、试验Ⅳ组、试验Ⅴ组(P0.01);试验Ⅰ组尿液维生素B2排出量极显著低于试验Ⅲ组、试验Ⅳ组、试验Ⅴ组(P0.01)。综合评价各指标,得到12月龄伊犁马对维生素B1的需要量为48.27 mg/(匹·d),对维生素B2的需要量为31.68 mg/(匹·d)。     

6月龄伊犁马对维生素B_1和维生素B_2适宜需要量的研究

试验旨在研究不同摄入水平维生素B_1(vitamin B_1,VB_1)、维生素B_2(vitamin B_2,VB_2)对6月龄伊犁马血浆VB_1含量、红细胞转酮酶活性(erythrocytetransketolase activity,E-TKA)、TPP效应及尿液VB_1排出量和血浆VB_2含量、红细胞谷胱甘肽还原酶活性系数(erythrocyte glutathione reductase activity coefficient,E-GRAC)及尿液VB_2排出量的影响,得到6月龄伊犁马对VB_1、VB_2的适宜需要量。试验选取月龄相近(6月龄)、平均体重为(117.12±13.33)kg、健康状况良好的伊犁马公马25匹,随机分为5组,每组5匹,分别为试验Ⅰ组、试验Ⅱ组、试验Ⅲ组、试验Ⅳ组、试验Ⅴ组,各组马匹每天饲喂相同营养水平日粮,分别添加0、10、20、30、40mg的VB_1和0、7、14、21、28mg的VB_2,进行为期20d的饲养试验。结果发现,随着VB_1实际摄入水平的升高,伊犁马血浆VB_1含量显著升高(P0.05),E-TKA显著提高(P0.05),TPP效应极显著降低(P0.01),尿液VB_1排出量显著增加(P0.05);随着VB_2实际摄入水平的升高,伊犁马血浆VB_2的含量显著升高(P0.05),E-GRAC极显著降低(P0.01),尿液VB_2排出量显著增加(P0.05)。以血浆VB_1含量、E-TKA、TPP效应及尿液VB_1排出量和血浆VB_2含量、E-GRAC及尿液VB_2排出量作为评价指标,得到6月龄伊犁马对VB_1、VB_2的适宜需要量分别为33.32和18.73mg/(匹·d)。     

蒙药黄芩与制粒对紫花苜蓿维生素和化学成分的影响

研究制粒工艺(制粒前、后)和添加黄芩(0、0.5%、1.0%、1.5%)对紫花苜蓿的营养品质、维生素含量、大肠杆菌与霉菌数量的影响,旨在了解制粒过程中紫花苜蓿的营养品质、维生素含量和微生物数量变化规律,探讨蒙药黄芩添加剂对紫花苜蓿维生素含量的保存、稳定作用。结果表明:制粒后,紫花苜蓿维生素B₂、维生素B₅、维生素B₆含量显著降低,而维生素K₁、维生素C含量显著升高;紫花苜蓿干物质和粗脂肪含量显著增加;大肠杆菌数量显著降低。添加1.5%黄芩显著提高了紫花苜蓿维生素C、维生素B₂、维生素B₆含量,而添加0.5%~1.0%黄芩显著降低了维生素K₁含量,添加1.5%黄芩显著降低了维生素B₁含量。综合两个因素的影响考虑,添加1.5%黄芩可显著提高紫花苜蓿草颗粒维生素C、维生素B₆含量;添加1.5%黄芩和制粒能显著提高紫花苜蓿粗脂肪含量。     

饲粮维生素B1添加水平对产蛋期种鹅繁殖性能、血清生殖激素指标、肠道组织形态及盲肠菌群结构的影响

本试验旨在研究饲粮维生素B₁添加水平对产蛋期种鹅繁殖性能、血清生殖激素指标、肠道组织形态及盲肠菌群结构的影响。试验选用150只体况相近的34周龄五龙鹅种鹅，随机分为6组，每组5个重复，每个重复5只鹅(1公4母)。各组维生素B₁添加水平分别为0(对照组)、1、2、3、4、5 mg/kg。预试期1周，正试期10周。结果表明：1)各组之间种蛋合格率、种蛋受精率、种蛋孵化率差异不显著(P>0.05)。2)各组之间血清催乳素、促黄体生成素、雌二醇、睾酮含量差异不显著(P>0.05)。2 mg/kg维生素B₁组血清孕酮含量显著高于对照组和1、3、4、5 mg/kg维生素B₁组(P<0.05),2、3 mg/kg维生素B₁组血清促卵泡素含量显著高于对照组(P<0.05)。3)2 mg/kg维生素B₁组空肠和回肠绒毛高度/隐窝深度显著高于对照组和5 mg/kg维生素B₁组(P<0.05)。4)2 mg/kg维生素B     

补喂复合益生菌对3~6月龄伊犁马粪便纤维含量、挥发性脂肪酸浓度和血浆细胞因子水平的影响

试验旨在研究补喂复合益生菌对3~6月龄伊犁马粪便纤维含量、VFA浓度和血浆细胞因子水平的影响。选取体重相近（90.23 kg±11.02 kg）、健康状况良好的3月龄伊犁马哺乳马驹10匹,随机分为2组,每组5匹,分别为对照组和试验组。在分阶段补喂等量营养水平的精料补充料和苜蓿干草的基础上,试验组每匹马驹每天补喂0.075 g（2×10¹¹ CFU/g）枯草芽孢杆菌和0.133 g（3×10¹⁰ CFU/g）植物乳杆菌复合菌,进行为期90 d的饲养试验。结果显示,补喂复合益生菌能够显著或极显著降低马驹粪便中酸性洗涤纤维（ADF）和淀粉的含量（P < 0.05;P < 0.01）,分别比对照组低3.50%和11.32%;显著或极显著提高马驹粪便中乙酸和丙酸的浓度（P < 0.05;P < 0.01）,分别比对照组高14.65%和64.29%;极显著提高血浆中肿瘤坏死因子α（TNF-α）的水平（P < 0.01）,比对照组高16.17%。由此可见,补喂复合益生菌能够降低马驹粪便中纤维的含量、提高挥发性脂肪酸（VFA）的浓度,增加3~6月龄伊犁马血浆细胞因子水平。     

维生素K3对14日龄北京鸭凝血时间和维生素K依赖蛋白的影响

旨在研究维生素K₃对1~14日龄北京鸭凝血时间和维生素K依赖蛋白的影响,筛选评价肉鸭维生素K营养状况的敏感指标,并得到育雏期北京鸭饲粮维生素K₃适宜添加量。试验采用单因子完全随机试验设计,设6个维生素K₃添加水平（0、0.5、1、2、3和4 mg·kg^-1）,通过在玉米-大豆分离蛋白型基础饲粮中添加6个不同添加水平亚硫酸氢钠甲萘醌配制试验饲粮。将180只1日龄健康雄性北京鸭随机分为6个处理组,每处理组5个重复,每重复6只鸭。试验期14 d。结果表明：不同添加水平维生素K₃对1~14日龄北京鸭平均日增重、平均日采食量和料重比等生长性能指标未产生显著影响（P>0.05）。0和0.5 mg·kg^-1维生素K₃添加组凝血酶原时间显著高于2、3、4 mg·kg^-1维生素K₃添加组（P<0.05）。0 mg·kg^-1维生素K₃添加组血清凝血酶原前体蛋白水平显著高于0.5、1、2、3、4 mg·kg^-1维生素K₃添加组（P<0.05）;0 mg·kg^-1维生素K₃添加组血清羧化不全骨钙素水平显著高于2、3、4 mg·kg^-1维生素K₃添加组（P<0.05）。以凝血酶原时间、血清凝血酶原前体蛋白和羧化不全骨钙素为评价指标,采用折线模型估算1~14日龄北京鸭维生素K₃需要量分别为2.00、0.56和1.27 mg·kg^-1。综上,饲粮中添加维生素K₃可增强肉鸭凝血功能,降低血清凝血酶原前体蛋白和羧化不全骨钙素水平。在本试验基础饲粮条件下,以凝血酶原时间为评价指标,采用折线模型估测1~14日龄北京鸭维生素K₃需要量为2.00 mg·kg^-1。     

17种植物性饲料原料中伏马毒素(B1+B2)、赭曲霉毒素A、T-2毒素、黄曲霉毒素B1污染状况调查检测分析

为了解掌握伏马毒素（B₁+B₂）、赭曲霉毒素A、T-2毒素、黄曲霉毒素B₁在植物性饲料原料中的污染状况,指导饲料生产企业和养殖企业开展霉菌毒素防控,降低霉菌毒素对饲料产品质量及畜禽养殖危害,减少经济损失,2019年对17种62份植物性饲料原料进行采集,采用液相色谱—串联质谱法、免疫亲和柱净化—高效液相色谱法检测,依据《饲料卫生标准》（GB 13078—2017）判定分析。结果表明：伏马毒素（B₁+B₂）、赭曲霉毒素A、黄曲霉毒素B₁在17种植物性饲料原料中的污染状况差别明显,伏马毒素（B₁+B₂）、赭曲霉毒素A、黄曲霉毒素B₁平均检出率分别为37.09%、8.06%、29.03%,最大检测值分别为15.96 mg/kg、26.60 μg/kg、351.00 μg/kg。从检测结果得出,4种霉菌毒素在17种植物性饲料原料中的污染较重,整体污染率达48.40%,玉米皮、喷浆玉米皮、花生粕3种植物性饲料原料中黄曲霉毒素B₁超标,污染率与超标率不一定呈正比,表明霉菌毒素在植物性饲料原料中污染普遍,对饲料产品及养殖安全造成严重影响。针对该问题,提出控制植物性饲料原料质量建议,为今后控制饲料原料中霉菌毒素含量提供参考。     

高效液相色谱法测定金荞麦超微粉原花青素B2含量

试验为测定金荞麦超微粉中有效成分原花青素B₂的含量,将四川金荞麦饮片粉碎至0.75 nm以下的超微粉,50%乙醇提取,并利用高效液相色谱测定原花青素B₂的含量。结果显示,在0.0352~1.4080 μg/mL范围内原花青素B₂与峰面积线性关系良好,回归方程为Y=59797X+592.3,r=0.996,金荞麦超微粉中原花青素B₂含量在1.305~1.541 mg/g之间。本试验结果表明该方法能快速、稳定、精确的检测原花青素B₂含量,为金荞麦制剂质量控制提供了科学依据。     

维生素E对H2O2诱导的奶牛乳腺上皮细胞氧化损伤及紧密连接相关基因表达的影响

试验通过研究维生素E （VE）对H₂O₂诱导的奶牛乳腺上皮细胞（MAC-T cells）氧化损伤及紧密连接相关基因表达的影响,旨在揭示维生素E对缓解奶牛乳腺细胞氧化应激的作用。试验设对照组（完全培养基处理组）、H₂O₂组和H₂O₂＋VE组。利用MTT法检测奶牛乳腺细胞存活率,比色法检测奶牛乳腺细胞培养液中超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性、丙二醛（MDA）和活性氧（ROS）含量;通过实时荧光定量PCR检测紧密连接基因ZO-1、occludin、claudin-1的相对表达量。结果显示,与对照组相比,H₂O₂组的奶牛乳腺上皮细胞存活率显著下降（P<0.05）,ROS和MDA含量显著增加（P<0.05）,SOD和CAT活性显著下降（P<0.05）;与H₂O₂组相比,H₂O₂＋20 μmol/L VE组的细胞存活率显著上升（P<0.05）,ROS和MDA含量显著下降（P<0.05）,SOD和CAT活性显著增加（P<0.05）。此外,与对照组相比,H₂O₂组极显著抑制了紧密连接基因的相对表达量（P<0.01）;而与H₂O₂组相比,添加维生素E极显著缓解了H₂O₂对紧密连接基因相对表达的抑制作用（P<0.01）。本研究结果证明,维生素E不仅能够减轻H₂O₂诱导的奶牛乳腺上皮细胞氧化损伤,还能缓解H₂O₂对紧密连接基因相对表达的抑制作用。     

AFB1降解剂对肉鸡生长性能、养分代谢及AFB1在体内残留的影响

通过在含有黄曲霉毒素B₁（aflatoxin B₁,AFB₁）的肉鸡日粮中添加AFB₁降解剂,测定其对肉鸡生长性能、养分代谢及AFB₁在血液、肝脏及肌肉中残留的影响。试验选择42日龄健康AA肉鸡75只随机分为5组,每组设5个重复。A组为对照组,饲喂基础日粮,B、C、D和E组在基础日粮中分别添加400、200、400和800 μg/kg AFB₁。B组为负对照组,C、D和E组分别添加0.15% AFB₁降解剂,试验期为30 d。试验结束时,测定肉鸡的生长性能、营养物质代谢率、体内AFB₁含量及抗氧化酶活性。结果表明：与AFB₁含量相同的B组相比,D组的平均日采食量和末重分别提高了32.45%、42.46%（P < 0.05）;与B组相比,其余各组的有机物、粗蛋白质、钙和磷的代谢率均有显著提高（P < 0.05）,D组的有机物和粗蛋白质消化率分别提高了9.50%和178.75%（P < 0.05）。血液、组织中AFB₁的测定结果表明,停喂AFB₁前,C组肝脏中AFB₁含量显著低于B组（P < 0.05）,停喂AFB₁24 h后,A和C组胸肌中AFB₁含量显著低于B、D和E组（P < 0.05）,停喂AFB₁48 h后,C、D组胸肌中AFB₁含量恢复到与对照组相同的水平。与B组相比,添加0.15% AFB₁降解剂的C、D和E组,血清和肝脏中谷胱甘肽过氧化物酶和超氧化物歧化酶活力显著提高（P < 0.05）。由此可见,在含有AFB₁的日粮中添加AFB₁降解剂,可缓解AFB₁对生长的抑制,提高养分消化率,加速AFB₁在肉鸡体内的代谢,减少AFB₁对机体的损伤。     

The effect of inflammation on the disposition of phenylbutazone in Thoroughbred horses

The effect of inflammation on the disposition of phenylbutazone (PBZ) was investigated in Thoroughbred horses. An initial study ( n = 5) in which PBZ (8.8 mg/kg) was injected intravenously twice, 5 weeks apart, suggested that the administration of PBZ would not affect the plasma kinetics of a subsequent dose. Two other groups of horses were given PBZ at either 8.8 mg/kg ( n = 5) or 4.4 mg/kg ( n = 4). Soft tissue inflammation was then induced by the injection of Freud's adjuvant and the administration of PBZ was repeated at a dose level equivalent to, but five weeks later than, the initial dose. Inflammation did not appear to affect the plasma kinetics or the urinary excretion of PBZ and its metabolites, oxyphenbutazone (OPBZ) or hydroxyphenylbutazone (OHPBZ) when PBZ was administered at 8.8 mg/kg. However, small but significant increases ( P <0.05) in total body clearance ( CL _B; 29.2 ± 3.9 vs. 43.8 ± 8.1 mL/ h-kg) and the volume of distribution, calculated by area ( V _d(area); 0.18 ± 0.05 vs. 0.25 ± 0.03 L/kg) or at steady-state ( V _d(SS); 0.17±0.04 vs. 0.25 ± 0.03 L/ kg), were obtained in horses after adjuvant injection, compared to controls, when PBZ was administered at 4.4 mg/kg which corresponded to relatively higher tissues concentrations and lower plasma concentrations (calculated) at the time of maximum peripheral PBZ concentration. Soft tissue inflammation also induced a significantly ( P <0.05) higher amount of OPBZ in the urine 18 h after PBZ administration but the total urinary excretion of analytes over 48 h was unchanged. These results have possible implications regarding the administration of PBZ to the horse close to race-day.     

饲粮钙磷水平对伊犁马初乳成分、乳脂脂肪酸组成、产后血液钙磷及激素的影响

旨在研究妊娠后期饲喂不同钙磷水平饲粮对产后伊犁马初乳成分、乳脂脂肪酸组成、血液钙磷及钙磷代谢激素、繁殖及生长代谢激素等生理生化指标的影响，为明确伊犁马在妊娠后期对钙磷的适宜需要量提供参考。本试验选取健康、无亲缘关系、12~13周岁、体重为（380±32）kg、胎次为4~5胎、处于第10妊娠月左右的伊犁马25匹，随机分为5组，每组5个重复。各组饲粮钙饲喂水平分别为36.00、39.00、42.00、45.00和48.00 g·d^-1，磷饲喂水平分别为26.30、28.30、30.30、32.30和34.30 g·d^-1。试验预试期10 d，正试期从第11天至母马分娩后第2天结束。母马分娩后12 h内采集初乳用于测定乳成分和乳脂脂肪酸含量，空腹血液用于测定Ca、P、甲状旁腺素（PTH）、降钙素（CT）、骨钙素（OC）、胎盘催乳素（PL）、垂体催乳素（PRL）、雌酮（E₁）、雌二醇（E₂）、血清孕酮（PROG）、甲状腺素（T₄）、三碘甲状腺原氨酸（T₃）、生长激素（GH）、胰岛素样生长因子-Ⅰ（IGF-1）等激素浓度。结果表明：1）饲粮钙磷水平对初乳中钙、磷、乳脂率、乳糖率均无显著影响，组间乳蛋白率、总固形物、体细胞数、乳脂中饱和脂肪酸（SFA）和不饱和脂肪酸（UFA）比例存在显著差异（P<0.05）。随着饲粮钙、磷水平的增加，乳磷浓度、乳蛋白率和UFA比例呈显著线性增加（P<0.05），总固形物呈显著二次增加（P<0.05），而乳糖率、SFA及肉豆蔻酸比例呈显著线性降低（P<0.05）。2）饲粮钙磷水平显著影响血液中OC和PROG浓度（P<0.05），随着饲粮钙磷水平的增加，血液中离子钙、CT和OC浓度呈显著的线性降低（P<0.05），而PTH和PROG水平呈显著的线性升高（P<0.05）。饲粮钙、磷水平对PL、PRL、E₁、E₂等生殖激素以及T₃、T₄、GH和IGF-1等生长代谢激素浓度均无显著影响。由此可见，在本试验条件下，饲粮钙磷通过提高初乳中乳蛋白率和总固形物来改变乳脂中饱和脂肪酸含量和不饱和脂肪酸比例影响初乳成分；通过降低血液中OC浓度影响钙磷代谢；通过提高血液中PROG浓度影响繁殖状况。     

Analysis of Speed Characteristics on 1000 m Trot Training Race in Yili Horse

In order to provide some reference on scientific training and determination of horse trot training race, experiment was conducted on analysis of speed characteristic of Yili horse trot training race. The grade of 7 Yili horses 1000 m trot training race and the speed per 50 m were measured, which was used as a research object and sample, by statistical analysis, correlation analysis, the difference of the linear regression method for quantitative analysis. It was resulted that between subsection speed (2 to 18) and average speed were significantly or extremely significantly correlated (P<0.05;P<0.01), the 9^th subsection speed had the highest relevancy; 6 high correlation subsection speeds were choosed for regression analysis, equation:Y=4.039X₉+2.256X₈－2.653X₁₆－1.361X₅－3.739X₁₃+2.529X₁₉－0.728. The experiment preliminary proved the difference among every subsection speed of 1000 m speed training race and the correlation between subsection speed and average speed, establishing a regression equation of subsection speed and average speed.     

Perturbed metabolism and hormonal profiles in calves infected with Sarcocystis cruzi

Plasma concentrations of growth hormone (GH), thyroid stimulating hormone (TSH), insulin (IN), thyroxine (T₄), and triiodothyronine (T₃) in addition to metabolic parameters [N balance (NB), urinary 3-methylhistidine (TMH), urinary creatinine (CR), and urinary hydroxyproline (HP)] were measured in 4-mo-old Holstein steers divided equally among groups infected with Sarcocystis (I), noninfected ad libitum fed (C), and noninfected pair fed to I (PF) (7 steers per treatment). Effects of infection on these parameters beyond those attributable to altered dietary intake were determined using orthogonal contrasts (effect of intake, C vs I + PF; effect of infection, PF vs I). NB was higher in C than I and PF (P<.05) and lower in I than PF (P<.02). Hydroxyproline and CR were influenced by intake (P<.05) and HP excretion was reduced in association with infection (P<.05). Reduced intake was associated with lowered mean basal plasma concentrations of GH, IN, T₃ and T₄ (P<.05). Infection further reduced (P<.001) plasma T₃ concentration.

Triiodothyronine and T₄ responses following an intravenous bolus of thyrotropin releasing hormone (TRH) were measured. The magnitude of the responses in I and PF were lower than those observed in C (P<.05). Plasma T₃ responses were further reduced in association with infection (P<.05). Insulin responses to intravenous arginine infusion (ARG) were also low in association with reduced intake. Growth hormone responses to TRH or ARG were affected by the level of feed intake only. These data suggest that hormonal perturbations associated with the insult of infection further compromise metabolism and the direction of nutrient partitioning that would ordinarily be associated with developmental growth in young steers beyond those responses anticipated from solely the reduction of feed intake.     

Effects of dietary protein and oathull fiber on nitrogen excretion patterns and postprandial plasma urea profiles in grower pigs

The objectives of this study were: 1) to determine if dietary protein reduction or oathull fiber inclusion would reduce urinary N excretion in grower pigs, 2) to determine if plasma urea could predict urinary N excretion among diets differing in protein and fiber content with an expected range in N excretion patterns, and 3) to determine the postprandial time point to sample blood for the best prediction. Three dietary protein concentrations (high, 19.7; medium, 16.9; low, 13.8%) and two fiber levels (high, 5.0; low, 3.6% crude fiber) were tested in a 3 x 2 factorial arrangement. Diets (wheat, barley, soybean meal; oathulls as fiber source) were formulated to 3.25 Mcal of digestible energy (DE)/kg and 2.2 g of digestible lysine/Mcal DE for low- and medium-protein diets, and 2.4 g/Mcal of DE for high-protein diets, and supplemented with lysine, methionine, tryptophan, threonine, isoleucine, or valine to meet an ideal amino acid profile. Pigs (32 +/- 3.4 kg; n = 42) were housed in metabolism crates for 19 d. On d 10 or 11, catheters were installed by cranial vena cava venipuncture. Daily feeding allowance was adjusted to 3x maintenance (3 x 110 kcal DE/kg body weight(0.75)), and was fed in two equal meals. Feces and urine were collected from d 15 to 19. Five blood samples were collected in 2-h intervals on d 16 and 19. Fecal, urinary, and total N excretion was reduced linearly with a reduction of dietary protein (P < 0.001); the reduction was greater for urinary (48%) and total N excretion (40%) than for fecal N excretion (23%). Similarly, the ratio of urinary to fecal N was reduced linearly with a reduction of dietary protein (P < 0.001). Retention of N (g/d) was reduced linearly, but N retention as a percentage of N intake was increased linearly with a reduction of dietary protein (P < 0.001). The addition of oathulls did not affect N excretion patterns and plasma urea (P > 0.10). Dietary treatments did not affect average daily gain or feed efficiency (P > 0.10). A dietary protein x time interaction affected plasma urea (P < 0.001). For medium- and high-protein diets, plasma urea increased postprandially, peaking 4 h after feeding, and then decreased toward preprandial levels (P < 0.05). Plasma urea did not alter postprandially for the low-protein diet (P > 0.10). Urinary N excretion (g/d) was predicted by 3.03 + 2.14 x plasma urea concentration (mmol/L) at 4 h after feeding (R2 = 0.66). Plasma urea concentration is indicative of daily urinary N excretion and reduction of dietary protein is effective to reduce total and urinary N excretion.     

补饲复合微生态制剂对泌乳期伊犁母马血液生化指标及抗氧化能力的影响

试验旨在研究补饲复合微生态制剂对泌乳期伊犁母马血液生化指标及抗氧化能力的影响.根据年龄、胎次、泌乳月龄相近的原则选择泌乳期伊犁母马24匹,随机分为4组,分别为对照组、试验Ⅰ组、试验Ⅱ组和试验Ⅲ组.对照组饲喂基础日粮,试验Ⅰ、Ⅱ、Ⅲ组在饲喂基础日粮的基础上分别补饲0.05 g枯草芽孢杆菌(活菌数为2.0×10¹¹ CFU/g)和0.133 g植物乳杆菌(活菌数为3.0×10¹⁰ CFU/g)、0.10 g枯草芽孢杆菌和0.266 g植物乳杆菌、0.15 g枯草芽孢杆菌和0.399 g植物乳杆菌.结果表明,与对照组相比,补饲复合微生态制剂对泌乳期伊犁母马血液中总蛋白、白蛋白、血尿素氮含量和谷胱甘肽过氧化物酶、超氧化物歧化酶活性的影响均差异不显著(P> 0.05);但补饲复合微生态制剂泌乳期伊犁母马血液中总蛋白、白蛋白含量和超氧化物歧化酶活性呈升高的趋势;试验Ⅱ组泌乳期伊犁母马血液中球蛋白含量显著高于对照组和试验Ⅰ组(P <0.05),其他各组之间差异不显著(P> 0.05).过氧化氢酶的活性试验Ⅱ组显著高于对照组和试验Ⅲ组(P <0.05),试验Ⅰ组与其他各组之间差异不显著(P> 0.05);总抗氧化能力试验Ⅱ组显著高于试验Ⅰ和Ⅲ组(P <0.05),其他各组之间差异不显著(P> 0.05).因此,补饲植物乳杆菌和枯草芽孢杆菌复合物对泌乳期母马增强免疫机能,改善氮沉积,提高机体抗氧化能力起到了一定作用,且补饲0.10 g枯草芽孢杆菌和0.266 g植物乳杆菌复合物时效果较为明显.     

The effect of vitamin C supplementation on plasma concentration and urinary excretion of vitamin C in cattle

We investigated the plasma concentration and urinary excretion of vitamin C in cows supplemented with vitamin C. Five cows (mean BW = 597 kg) were allocated to a 5 x 5 Latin square design and supplemented with a vitamin C preparation coated with hydrogenated soybean oil at 0, 10, 20, 40, or 60 mg of vitamin C per kg of BW per day for 9 d. Plasma and urine samples were collected for measuring vitamin C concentration. Urinary excretion of vitamin C was expressed as the ratio of vitamin C to creatinine. Plasma vitamin C concentration and urinary vitamin C excretion increased quadratically as dietary vitamin C increased (P < 0.001); that is, the lowest dose affected neither plasma vitamin C concentration nor urinary vitamin C excretion but the plasma vitamin C concentration and urinary vitamin C excretion increased (P < 0.05) with increasing supplementation of vitamin C at greater doses. This suggests that plasma vitamin C concentration affects urinary excretion of vitamin C in cattle and that plasma vitamin C concentration exceeded the renal threshold for vitamin C in the cows receiving vitamin C at 20 mg/kg of BW per day. Furthermore, increased urinary excretion of vitamin C appears to limit plasma vitamin C concentration in response to vitamin C intake. The daily excretion of vitamin C was estimated by the reported value of daily creatinine excretion, indicating that the daily amount of vitamin C excreted into urine was more than half of supplied vitamin C. Therefore, a large part of supplied vitamin C probably escapes ruminal degradation and is absorbed but excreted into urine.     

不同氨化处理黄曲霉毒素B_1脱毒效果及其对奶牛瘤胃体外发酵的影响

试验旨在研究不同氨化处理对黄曲霉毒素B_1(AFB_1)的脱毒效果及其对奶牛瘤胃体外发酵的影响。本研究分为两个试验。试验一:对人工感染2 550μg/kg AFB_1的玉米和大米混合物(1∶3)进行氨化处理,分为对照组(Ⅰ组,未处理)和试验组Ⅱ(0.1Mpa,1h)、Ⅲ(0.1 Mpa,2h)、Ⅳ(0.1 Mpa,3h)、Ⅴ(0.2 Mpa,1h)、Ⅵ(0.2 Mpa,2h)、Ⅶ(0.2Mpa,3h)、Ⅷ(0.3Mpa,1h)、Ⅸ(0.3Mpa,2h)、Ⅹ(0.3Mpa,3h)组,每组3个重复,测定不同氨化处理的AFB_1的脱毒效果及混合物的营养成分。试验二:研究氨化处理AFB_1对奶牛体外发酵指标的影响。试验设对照组(Ⅰ组,未处理)和试验组Ⅱ(0.3Mpa,1h)、Ⅲ(0.3Mpa,2h)、Ⅳ(0.3Mpa,3h)组,每组3个重复,测定体外发酵2、4、8、12、24和48h的产气量、发酵液pH、体外干物质降解率(IVDMD)、氨态氮(NH3-N)和挥发性脂肪酸(VFA)。结果显示:在试验一中,试验组粗蛋白质(CP)含量均显著高于对照组(P<0.05);Ⅹ组(0.3 Mpa,3h)AFB_1含量显著低于其他组(除Ⅶ组外)(P<0.05)。在试验二中,Ⅳ组(0.3 Mpa,3h)发酵液pH显著低于对照组(P<0.05),体外发酵产气量、挥发性脂肪酸、氨态氮含量和体外干物质降解率(除48h外)均显著高于对照组(P<0.05),而Ⅱ(0.3Mpa,1h)和Ⅲ组(0.3Mpa,2h)组效果不明显。综上所述,氨化处理能够显著降低样品中AFB_1含量,提高CP含量,改善瘤胃发酵,其中0.3Mpa、3h处理效果最佳。     

日粮粗蛋白质水平对伊犁鹅产蛋规律、繁殖激素分泌及相关基因mRNA表达的影响

为探讨日粮粗蛋白质水平对伊犁鹅的产蛋规律、繁殖激素分泌及生殖轴相关基因mRNA表达量的影响,本研究随机选取200只3岁伊犁鹅（年龄、饲养管理水平一致及体重相近）,随机分为4个组,每组10个重复。对照组及公鹅饲喂鹅场自配料（粗蛋白质水平11.20%）,试验组母鹅分别饲喂粗蛋白质水平为13.86%、15.20%和16.48%的日粮,其余营养指标基本一致。预试期1周,正试期9周。结果表明：①试验期内伊犁鹅的产蛋率呈波动变化,对照组伊犁鹅的产蛋率在第1~2周逐渐上升,第4~5周出现小幅度增长,其余阶段表现为下滑趋势;各试验组伊犁鹅的产蛋率在第1~2、4~5周出现较大幅度增长,且在第5周时达到产蛋高峰,此后逐渐下滑。15.20%粗蛋白质组伊犁鹅就巢率显著低于11.20%、13.86%粗蛋白质组。②与对照组相比,13.86%粗蛋白质组血清促性腺激素释放激素（GnRH）浓度极显著升高（P<0.01）,且血清雌二醇（E₂）、促黄体素（LH）浓度均显著升高（P<0.05）;15.20%、16.48%粗蛋白质组血清GnRH、E₂及LH浓度均极显著升高（P<0.01）,且血清促卵泡素（FSH）浓度显著升高（P<0.05）。各试验组血清催乳素（PRL）浓度均显著降低（P<0.05）。③与对照组相比,15.20%粗蛋白质组下丘脑GnRH、LHR基因表达量显著上调（P<0.05）,PRL、PRLR基因表达量显著下调（P<0.05）;垂体中LH基因表达量显著上调（P<0.05）;卵巢中LH与ESR2基因表达量显著或极显著上调（P<0.05,P<0.01）。综上所述,基于日粮粗蛋白质水平对伊犁鹅的产蛋率、就巢率、血清生殖激素浓度及生殖轴相关基因mRNA相对表达量影响的综合评估,建议产蛋期伊犁鹅日粮粗蛋白质水平为15.20%。