脱氧雪腐镰刀菌烯醇暴露对仔猪海马神经细胞神经递质、脂质过氧化及钙稳态的影响北大核心CSCD

本试验旨在研究脱氧雪腐镰刀菌烯醇(DON)暴露对体外培养的仔猪海马神经细胞中神经递质、脂质过氧化及钙稳态的影响,探讨DON的神经毒性作用。以不同质量浓度的DON(0、125、250、500、1 000和2 000 ng/m L)处理仔猪海马神经细胞24 h后,检测细胞中5-羟色胺(5-HT)、多巴胺(DA)、乙酰胆碱(ACH)、γ-氨基丁酸(GABA)、去甲肾上腺素(NE)含量,总抗氧化能力(T-AOC)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和一氧化氮(NO)、丙二醛(MDA)含量,钙离子(Ca2+)、钙调蛋白(Ca M)含量以及Ca M m RNA相对表达量。结果表明:与对照组相比,1)当DON浓度为1 000 ng/m L时,5-HT、DA、ACH含量显著升高(P<0.05),GABA含量极显著升高(P<0.01),而NE含量显著降低(P<0.05);当DON浓度为2 000 ng/m L时,5-HT、DA、ACH含量极显著升高(P<0.01)。2)当DON浓度为250 ng/m L时,SOD活性和T-AOC极显著降低(P<0.01);当DON浓度为1 000 ng/m L时,GSH-Px活性显著降低(P<0.05),NO含量极显著降低(P<0.01),而MDA含量极显著升高(P<0.01);当DON浓度为2 000 ng/m L时,CAT活性显著降低(P<0.05),GSH-Px活性极显著降低(P<0.01)。3)当DON浓度为125 ng/m L时,Ca M含量极显著升高(P<0.01);当DON浓度为250 ng/m L及以上时,Ca2+含量和Ca M m RNA相对表达量极显著升高(P<0.01)。综上,DON暴露可改变仔猪海马神经细胞神经递质的分泌及脂质过氧化,并影响钙稳态,对仔猪海马神经细胞具有一定的神经毒性作用。     

乳化异氟醚全凭静脉麻醉对大鼠海马钙调蛋白信号转导系统的影响

旨在探讨海马中钙调蛋白信号转导系统在大鼠乳化异氟醚静脉麻醉过程中的调控作用和变化规律,将24只大鼠分为对照组、浅麻醉组、深麻醉组和苏醒组。采集各组大鼠海马组织,经RT-PCR检测海马样品中钙调蛋白(CaM)、钙调蛋白依赖性蛋白激酶Ⅱ(CaMKⅡ)和钙调神经磷酸酶(CaN)的mRNA表达水平。结果显示:浅麻醉组大鼠海马CaM、CaMKⅡ和CaN mRNA表达水平较对照组显著降低(P0.05),深麻醉组3种mRNA表达水平较对照组极显著降低(P0.01),苏醒期3种mRNA表达水平与对照组无显著差异(P0.05)。结果表明,乳化异氟醚抑制了海马CaM、CaMKⅡ和CaN mRNA表达,海马钙调蛋白信号转导系统参与了乳化异氟醚麻醉调控过程,本试验为揭示乳化异氟醚麻醉机理提供了新的研究方向。     

脱氧雪腐镰刀菌烯醇暴露对仔猪海马神经细胞神经递质、脂质过氧化及钙稳态的影响

本试验旨在研究脱氧雪腐镰刀菌烯醇(DON)暴露对体外培养的仔猪海马神经细胞中神经递质、脂质过氧化及钙稳态的影响,探讨DON的神经毒性作用。以不同质量浓度的DON(0、125、250、500、1 000和2 000 ng/m L)处理仔猪海马神经细胞24 h后,检测细胞中5-羟色胺(5-HT)、多巴胺(DA)、乙酰胆碱(ACH)、γ-氨基丁酸(GABA)、去甲肾上腺素(NE)含量,总抗氧化能力(T-AOC)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和一氧化氮(NO)、丙二醛(MDA)含量,钙离子(Ca2+)、钙调蛋白(Ca M)含量以及Ca M m RNA相对表达量。结果表明:与对照组相比,1)当DON浓度为1 000 ng/m L时,5-HT、DA、ACH含量显著升高(P0.05),GABA含量极显著升高(P0.01),而NE含量显著降低(P0.05);当DON浓度为2 000 ng/m L时,5-HT、DA、ACH含量极显著升高(P0.01)。2)当DON浓度为250 ng/m L时,SOD活性和T-AOC极显著降低(P0.01);当DON浓度为1 000 ng/m L时,GSH-Px活性显著降低(P0.05),NO含量极显著降低(P0.01),而MDA含量极显著升高(P0.01);当DON浓度为2 000 ng/m L时,CAT活性显著降低(P0.05),GSH-Px活性极显著降低(P0.01)。3)当DON浓度为125 ng/m L时,Ca M含量极显著升高(P0.01);当DON浓度为250 ng/m L及以上时,Ca2+含量和Ca M m RNA相对表达量极显著升高(P0.01)。综上,DON暴露可改变仔猪海马神经细胞神经递质的分泌及脂质过氧化,并影响钙稳态,对仔猪海马神经细胞具有一定的神经毒性作用。     

脱氧雪腐镰刀菌烯醇(DON)暴露对断奶仔猪血清及小肠黏膜免疫功能的影响

旨在研究脱氧雪腐镰刀菌烯醇(DON)暴露对断奶仔猪血清及肠道黏膜免疫功能的影响。选择30头21日龄临床检查健康的"杜×长×大"三元杂交断奶仔猪,体质量(6.87±0.41)kg,随机分为3组,对照组饲喂基础日粮,低剂量组和高剂量组分别饲喂含1,2 mg/kg的DON日粮,试验期为60 d。试验结束时,所有仔猪经前腔静脉采血,分离血清,用于检测免疫因子含量;同时每组随机选择5头仔猪进行屠宰,收集免疫器官及各段小肠,用于检测免疫器官指数及小肠组织中免疫球蛋白的表达水平。结果显示:与对照组相比,DON处理组仔猪血清中分泌型免疫球蛋白A(sIgA)、免疫球蛋白M(IgM)、免疫球蛋白G(IgG)、补体3(C3)及补体4(C4)含量均显著或极显著降低(P<0.05或P<0.01);试验组仔猪脾脏指数较对照组显著或极显著降低(P<0.05或P<0.01);小肠各段肠黏膜中免疫球蛋白表达水平均随DON含量的增加而显著或极显著降低(P<0.05或P<0.01)。结果表明,在本试验条件下,DON可降低断奶仔猪的体液免疫及肠道黏膜免疫水平,改变仔猪的免疫功能。     

呕吐毒素处理对伴刀豆球蛋白A刺激鸡脾脏淋巴细胞的体外影响

本试验研究了呕吐毒素(DON)处理对伴刀豆球蛋白A(CoA)刺激脾脏淋巴细胞的体外影响。鸡脾脏分离得到的淋巴细胞用12.5μg/mL CoA刺激,然后用不同浓度(0~50μg/mL)DON处理18小时,测定了细胞内钙离子浓度、pH值、钙调蛋白(CaM)mRNA水平和Na~+,K~+-ATP酶及Ca~(2+)-ATP酶活性。结果显示,随着DON处理水平提高,细胞内钙离子浓度和CaM mRNA水平呈剂量依赖性升高,也相同程度提高了ATP酶活性,处理组和对照组间差异达到显著或极显著水平(P0.05或P0.01)。试验结果提示,细胞内钙稳态失调和酸化是DON对鸡淋巴细胞毒性的关键机制。     

醋酸铅对体外培养SD大鼠成骨细胞的毒性

利用不同浓度的醋酸铅溶液(0、20、40、80μmol/L)作用成骨细胞24 h,研究醋酸铅对体外培养新生SD大鼠成骨细胞增殖分化和钙调蛋白(Calmodulin,CaM)的影响。结果表明,成骨细胞的增殖功能和ALP活性随着醋酸铅浓度的增加而显著降低(P<0.05或P<0.01),呈现一定的剂量-效应关系;与对照组相比,染铅组成骨细胞ALP活性显著下降(P<0.05),而钙调蛋白mRNA和蛋白的表达逐渐增加,当铅浓度为40μmol/L时,差异显著或极显著(P<0.05或P<0.01)。表明醋酸铅通过影响成骨细胞的增殖分化活力、ALP活性和钙调蛋白的表达,发挥其毒性损伤作用。     

红芪粗多糖对免疫应激断奶仔猪生长性能、血清生化指标和抗氧化能力的影响

本试验旨在研究红芪粗多糖(CHPS)对细菌脂多糖(LPS)刺激断奶仔猪生长性能、血清生化指标和抗氧化能力的影响。选择健康的32头断奶仔猪,按体重相近的原则随机分为5组:对照组(基础饲粮)、LPS组(基础饲粮+LPS)、CHPS低剂量组(基础饲粮+LPS+200 mg/kg CHPS)、CHPS高剂量组(基础饲粮+LPS+800 mg/kg CHPS),每组8个重复,每个重复1头仔猪。试验期为28 d。试验期间记录每头猪日采食量,试验第1、21、28天称重,计算各阶段平均日采食量、平均日增重和料重比。试验第21天,LPS组以及CHPS低、高剂量组仔猪腹膜注射100μg/kg BW LPS,对照组注射等量的生理盐水,注射后3 h,前腔静脉采血,分离血清,测定血清生化指标。结果表明:1)与对照组相比,应激期(22～28 d)LPS组平均日采食量和平均日增重均极显著下降(P<0.01);血清碱性磷酸酶、谷丙转氨酶活性及甘油三酯、总胆固醇、尿素氮和丙二醛含量均显著或极显著升高(P<0.05或P<0.01),一氧化氮合酶活性显著下降(P<0.05)。2)与LPS组相比,CHPS高、低剂量组平均日采食量和平均日增重均显著升高(P<0.05);CHPS低剂量组血清甘油三酯、总胆固醇和丙二醛含量均显著或极显著降低(P<0.05或P<0.01);CHPS高剂量组血清碱性磷酸酶活性极显著降低(P<0.01)。结果提示,在饲粮中添加一定剂量的CHPS能够有效缓解LPS所致免疫应激引起的断奶仔猪生长性能下降,可降低血清甘油三酯、总胆固醇、丙二醛含量及碱性磷酸酶活性,说明CHPS可以有效缓解LPS所致仔猪免疫应激。     

脱氧雪腐镰刀菌烯醇与玉米赤霉烯酮联合暴露对体外培养鸡脾脏淋巴细胞内环境稳态的影响

本试验旨在研究脱氧雪腐镰刀菌烯醇(DON)与玉米赤霉烯酮与(ZEA)联合暴露对体外培养鸡脾脏淋巴细胞内环境稳态的影响。分别以0.012 50μg/mL DON+0.006 25μg/mL ZEA、0.050μg/mL DON+0.025μg/mL ZEA、0.2μg/mL DON+0.1μg/mL ZEA、0.8μg/mL DON+0.4μg/mL ZEA对体外培养鸡脾脏淋巴细胞进行联合暴露培养,48 h后测定细胞膜ATP酶(Ca~(2+)-ATP酶、Na~+/K~+-ATP酶)活性以及细胞内pH、Ca~(2+)水平和钙调蛋白(CaM)的mRNA表达水平。同时设不添加毒素的空白对照组。结果表明:添加毒素的各试验组间,细胞内Ca~(2+)水平、CaM mRNA表达水平随毒素浓度的升高而增加,且添加毒素的各试验组均显著或极显著高于空白对照组(P0.05或P0.01)。细胞内pH以及细胞膜Ca~(2+)-ATP酶与Na~+/K~+-ATP酶活性均随毒素浓度的升高而降低,且添加毒素的各试验组均显著或极显著低于空白对照组(P0.05或P0.01)。由此得出,DON、ZEA联合暴露导致体外培养鸡脾脏淋巴细胞内酸化、离子平衡失调等一系列细胞内环境稳态失衡,且呈剂量依赖性。     

血府逐瘀汤对冠心病血瘀模型家兔氧化应激的影响

为观察血府逐瘀汤对冠心病(CHD)血瘀模型家兔氧化应激的影响,将清洁级健康家兔随机分为对照组,模型组,假手术组,血府逐瘀汤低剂量、中剂量、高剂量6组,每组8只。模型组、低剂量、中剂量、高剂量组采用左冠状动脉放置缩窄环方法,制备冠心病模型。低剂量、中剂量、高剂量组以血府逐瘀汤按10、20、40g/kg体重灌胃,每天1次,连续21d。对照组、模型组、假手术组则给予等体积生理盐水。检测血管紧张素Ⅱ(AngⅡ)、活性氧(ROS)、肌酸激酶(CK)、乳酸脱氢酶(LDH)、总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)、谷胱甘肽(GSH)、丙二醛(MDA)水平、NADPH氧化酶亚型2(NOX2)表达。结果表明,与对照组比较,模型组AngⅡ、ROS、CK、LDH、MDA水平显著或极显著升高(P0.05或P0.01),TAOC、SOD、GSH水平显著或极显著下降(P0.05或P0.01),NOX2表达增多。与模型组比较,中剂量、高剂量组AngⅡ、ROS、CK、LDH、MDA水平显著或极显著降低(P0.05或P0.01),而T-AOC、SOD、GSH水平显著或极显著升高(P0.05或P0.01),NOX2表达减少。提示血府逐瘀汤具有减轻心肌细胞氧化损伤作用,可能是其治疗CHD的部分起效环节。     

复方中药对高海拔肉鸡腹水综合征血液指标和抗氧化性能的影响

为了研究自制复方中药对患腹水综合征高海拔肉鸡血液指标和肺组织抗氧化性能的影响,试验将150只8日龄肉仔鸡随机分为3组,即模型对照组(高海拔环境),复方中药低剂量组(高海拔环境+低剂量复方中药添加剂)、复方中药高剂量组(高海拔环境+高剂量复方中药添加剂),3组均采用常规日粮+Na~+浓度为0.12%饮水复制肉鸡腹水综合征,42日龄检测血常规、血液生化指标和肺组织抗氧化指标。结果表明:与模型对照组比,复方中药低剂量组肉鸡的白细胞(WBC)、血细胞比容(PCV)、血小板压积(PCT)显著降低(P0.05),红细胞平均血红蛋白含量(MCH)、红细胞平均血红蛋白浓度(MCHC)、白蛋白浓度(ALB)、球蛋白浓度(GLB)显著升高(P0.05),红细胞数(RBC)、血红蛋白浓度(Hb)极显著降低(P0.01);复方中药高剂量组WBC、血小板总数(PLT)、PCT显著降低(P0.05),MCH、总蛋白(TP)、ALB、GLB显著升高(P0.05),RBC、Hb、PCV、平均血小板体积(MPV)极显著降低(P0.01),MCHC极显著升高(P0.01)。与模型对照组比,复方中药低剂量组和复方中药高剂量组鸡肺组织丙二醛(MDA)极显著降低(P0.01),复方中药低剂量组鸡肺组织超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性显著提高(P0.05);复方中药高剂量组鸡肺组织SOD和GSH-Px活性极显著提高(P0.01)。说明自拟中药复方可增强血液流通,肝脏蛋白代谢水平,改善血液指标;减少高原腹水综合征肉鸡肺组织自由基和脂质过氧化物数量,提高抗氧化能力,复方中药组方对预防高海拔肉鸡腹水综合征取得了较好地效果,且高剂量组优于低剂量组。     

不同青贮玉米品种抗病性评价

对10个青贮玉米品种自然发病情况进行调查,并采用病级分类方法对抗病性分类。结果表明:对锈病表现抗性和中抗的品种有3个和5个,分别占供试品种的30%和50%;对大斑病表现抗性和中抗的品种有4个和5个,分别占供试品种的40%和50%;对褐斑病表现抗性和中抗的品种有6个和3个,分别占供试品种的60%和30%;对小斑病表现抗性和中抗的品种有6个和3个,分别占供试品种的60%和30%。多数品种对青贮玉米4种病害抗性表现较好,可从青贮玉米供试材料中选用优良抗病材料用于四川地区种植。     

Evaluation of Oxygen-dependent Immunodefences of the Polymorphonuclear Cells of Some Tropical Ruminants

Activation of polymorphonuclear cells (PMNs) leads to the formation of superoxide, which is in turn dismutated to H₂O₂ by superoxide dismutase (SOD) and is partly responsible for oxygen-dependent microbicidal activity. However, no comparative information is available on the effect of SOD inhibition before PMN activation to allow simulation of the SOD defects that are known to occur in some ruminants. This paper attempts to examine the degranulative and phagocytic responses in buffalo, cattle and goat PMNs exposed to diethyldithiocarbamate, a known SOD inhibitor. The activity of glutathione peroxidase and reductase was increased in the presence of SOD inhibitor. On activation, H₂O₂ production increased significantly (p<0.01), while SOD inhibition before the activation of PMNs caused a significant decline in the production of H₂O₂ (p<0.05) in all the species studied. There was a significant increase (p<0.05) in the phagocytosis of Candida albicans spores by buffalo PMNs activated with opsonized zymosan. Activation of bovine PMNs after exposure to the SOD inhibitor resulted in a significant decline (p<0.05) in phagocytic activity; in the other species, the two values only approached significance. Among the activators, opsonized zymosan caused a significant increase in phagocytic activity as compared to lipopolysaccharide, particularly in the PMNs of buffaloes (p<0.05). Increased fungicidal activity (p<0.05) occurred with opsonized zymosan-activated PMNs of all the species studied. The fungicidal activity was found to decline in PMNs exposed to SOD inhibitor before activation (p<0.05). Interestingly, the phagocytic activity of caprine PMNs was found to be lower than that of PMNs from cattle (p<0.05).     

Effect of dietary stable isotopic ratios of carbon and nitrogen on the extent of their incorporation into tissues of rats

This study was conducted to investigate the effect of different dietary ratios of ¹³ C to ¹² C or ¹⁵ N to ¹⁴ N on their relative incorporation into tissues. Eighty male rats were used in two 21-day feeding trials in which they were fed diets with either high δ¹³C levels (δ¹³C = −13.89‰ and δ¹⁵N = 2.37‰ in experiment 1 and δ¹³C = −19.34‰ and δ¹⁵N = 4.73‰ in experiment 2) or low δ¹³C levels (δ¹³C = −17.90‰ and δ¹⁵N = 3.08‰ in experiment 1 and δ¹³C = −21.76‰ and δ¹⁵N = 0.53‰ in experiment 2), meanwhile, the dietary δ¹⁵N levels were designed to two ranks. Blood, liver, adipose and muscle tissues were collected on day 0, 3, 7, 14, and 21 for determination of ¹³ C, ¹² C, ¹⁵ N and ¹⁴ N isotopes. Rat growth rate, antioxidant capacity and metabolic parameters were also assessed. The results indicate that adipose tissue tend to deplete ¹³ C before the stable isotopic ratios achieved final equilibrium. Therefore, feeds with different isotopic signatures had different incorporation rates into tissues. Low dietary ¹³ C levels decreased tissue δ¹³C values whereas high dietary ¹³ C levels did not alter tissue δ¹³C values during the 21-d experiment. Blood δ¹⁵N values were a reliable parameter in assessing the relative contribution of dietary nitrogen to tissues. This study revealed a relationship between dietary isotopic signatures and their incorporation rates into rat tissues. However, more studies are needed to illustrate the mechanism through which dietary isotopic ratios influence the extent of isotopic incorporation into the tissues.     

Pharmacokinetics of three formulations of vitacoxib in horses

The pharmacokinetic properties of three formulations of vitacoxib were investigated in horses. To describe plasma concentrations and characterize the pharmacokinetics, 6 healthy adult Chinese Mongolian horses were administered a single dose of 0.1 mg/kg bodyweight intravenous (i.v.), oral paste, or oral tablet vitacoxib in a 3-way, randomized, parallel design. Blood samples were collected prior to and at various times up to 72 hr postadministration. Plasma vitacoxib concentrations were quantified using UPLC-MS/MS, and pharmacokinetic parameters were calculated using noncompartmental analysis. No complications resulting from the vitacoxib administration were noted on subsequent administrations, and all procedures were tolerated well by the horses throughout the study. The elimination half-life (T_1/2λz) was 4.24 ± 1.98 hr (i.v.), 8.77 ± 0.91 hr (oral paste), and 8.12 ± 4.24 hr (oral tablet), respectively. Maximum plasma concentration (C_max) was 28.61 ± 9.29 ng/ml (oral paste) and 19.64 ± 9.26 ng/ml (oral tablet), respectively. Area under the concentration-versus-time curve (AUC_last) was 336 ± 229 ng hr/ml (i.v.), 221 ± 94 ng hr/ml (oral paste), and 203 ± 139 ng hr/ml, respectively. The results showed statistically significant differences between the 2 oral vitacoxib groups in T_max value. T_1/2λz (hr), AUC_last (ng hr/ml), and MRT (hr) were significantly different between i.v. and oral groups. The longer half-life observed following oral administration was consistent with the flip-flop phenomenon.     

Determination of optimal dietary selenium levels by full expression of selenoproteins in various tissues of broilers from 1 to 21 d of age

The current NRC dietary selenium (Se) requirement (0.15 mg/kg) of broilers is primarily based on growth performance data reported in 1986. Our study aimed to determine optimal dietary Se levels of broilers fed a practical corn-soybean meal diet for the full expression of selenoproteins in various tissues. A total of 384 one-d-old male broilers (n = 8 replicates/diet) were fed a basal corn-soybean meal diet or the basal diet supplemented with 0.1, 0.2, 0.3, 0.4 or 0.5 mg Se/kg in the form of Na₂SeO₃ for 21 d. Regression analysis was conducted to evaluate the optimal dietary Se levels using broken-line, quadratic or asymptotic models. The activity of glutathione peroxidase (GPX) in the plasma, liver, kidney and pancreas, iodothyronine deiodinase (DIO) in the plasma, liver and pancreas, and thioredoxin reductase (Txnrd) in the liver and pancreas, the mRNA levels of Gpx1, Gpx4, Dio1, selenoprotein (Seleno) h, Selenop and Selenou in the liver, Gpx4, Dio1, Txnrd1, Txnrd2, Selenoh, Selenop and Selenou in the kidney, and Gpx1, Gpx4, Selenoh and Selenou in the pancreas, and the protein levels of GPX4 in the liver and kidney of broilers were influenced (P < 0.05) by added Se levels, and increased quadratically (P < 0.05) with the increase of added Se levels. The estimates of optimal dietary Se levels were 0.07 to 0.36 mg/kg based on the fitted broken-line, quadratic or asymptotic models (P < 0.001) of the aforementioned selenoprotein expression in the plasma, liver and kidney, and 0.09 to 0.46 mg/kg based on the fitted broken-line models (P < 0.001) of the aforementioned selenoprotein expression in the pancreas. The results indicate that the optimal dietary Se levels would be 0.36 mg/kg to support the full expression of selenoproteins in the plasma, liver and kidney, and 0.46 mg/kg to support the full expression of selenoproteins in the pancreas of broilers fed a practical corn-soybean meal diet from 1 to 21 d of age.     

Influence of fibre and betaine on development of the gastrointestinal tract of broilers between hatch and 14 d of age

An experiment was designed to determine the influence of fibre and betaine on the development of the intestine, liver and pancreas of broilers from hatch to 14 d of age. A total of 250-day-old Cobb 500 male broilers were allocated to 16 cages with 15 broilers each. Treatments were arranged in a 2 × 4 factorial design, consisting of 2 feed formulations (low and high fibre diets) and 4 levels of betaine (0, 1, 3 or 5 kg/t). At hatch, 10 birds in total were euthanised, and samples of the liver, pancreas, yolk sac and intestine were collected for reference of the analysed parameters before the start of the trial. On d 4, 9 and 14, 5 birds per cage (10 birds per treatment) were selected, euthanised and treated as the same as the birds at hatch. Villus height and width and crypt depth were determined on the duodenum samples, and absorptive area was calculated. The number of enterocytes in mitosis at the villus was determined by a positive reaction to antibody for Ki67 protein, and fused villus was evaluated visually. The relative weight of the yolk sac reduced (P < 0.05) as birds aged while the intestine and liver reached a maximum (P < 0.05) at around d 4 and the pancreas at d 9. Birds fed the high fibre diet had greater feed intake, lower relative weight of the pancreas and higher villus (P < 0.05) than birds fed the low fibre diet. Villus width increased (P < 0.05) at 4 d of age, and this was associated with fused villus. Betaine inclusion reduced (P < 0.05) villus width, increased (P < 0.05) villus size and absorptive area, and reduced (P < 0.05) the number of enterocytes with positive reaction for the antibody Ki-67. Betaine inclusion reduced the width and increased the absorptive area and the villus height of the duodenum of birds up to 14 d of age. The higher fibre diet increased feed intake and villus height, yet reduced pancreas relative weight, while not affecting body weight gain. This response was possibly due to a dilution effect of the fibre, reducing nutrient absorption and consequently stimulating villus growth to improve absorption rates.     

Effects of GnRH treatment on initiation of pulses of LH,LH release,and subsequent concentrations of progesterone

Progesterone is essential for establishment and maintenance of pregnancy. One proposed method to increase progesterone is administering GnRH at insemination. However, this method has resulted in conflicting results. Therefore, 2 experiments were conducted to evaluate how administering GnRH at insemination affected pulses of luteinizing hormone (LH) and subsequent progesterone. In Experiment 1, cows were allotted to 2 treatments: (1) GnRH (100 μg) given approximately 12 h after initiation of estrus (n = 5); and (2) Control (n = 5). Blood samples were collected at 15-min intervals for 6 h at 12 (blood sampling period 1), 26 (blood sampling period 2), 40 (blood sampling period 3), 54 (blood sampling period 4), and 68 (blood sampling period 5) h after onset of estrus. Daily blood samples were collected for 17 d. In Experiment 2, cows were allotted into 2 treatments: GnRH administered 10 to 11 h (n = 10) or 14 to 15 h (n = 10) after onset of estrus. Daily blood samples were collected for 17 d. Cows treated with GnRH tended (P ≤ 0.075) to have greater LH release during blood sampling period 1, tended (P = 0.095) to have fewer pulses during blood sampling period 2, tended (P = 0.067) to have greater concentrations of progesterone, and had an earlier (P = 0.05) increase in progesterone than control cows. Cows treated with GnRH 10 to 11 h after onset of estrus had greater (P = 0.01) progesterone and an earlier (P = 0.04) increase in progesterone than cows treated 14 to 15 h. In conclusion, timing of GnRH treatment following onset of estrus influenced pulses of LH and subsequent progesterone.     

In Vitro Evaluation of the Effects of Selected Plants on the Growth of the Mycelial Form of Histoplasma capsulatum Variety farciminosum in Ethiopia

Epizootic lymphangitis is prevalent in equines in Ethiopia, causing remarkable economic and welfare impacts but often neglected. Lack of effective treatment contributed to its continued occurrence, and hence, search for an effective treatment should be considered a priority area to minimize its impacts. Previous ethnobotanical studies have reported that Curcuma longa, Phytolacca dodecandra, and Datura stramonium were used to treat cutaneous fungal infections and reduce their incidence. The treatment effects of these plants against epizootic lymphangitis should be studied. The in vitro growth inhibitory effects of methanol extracts of the root of C. longa, berry of P. dodecandra, and leaf of D. stramonium were evaluated. Histoplasma capsulatum var farciminosum was isolated from clinical cases of epizootic lymphangitis in carthorses in central Ethiopia. The nested polymerase chain reaction was used to confirm the identity of the isolates. Serial twofold dilutions of the extract of berries of P. dodecandra and leaves of D. stramonium were done in sterile water, whereas dilution of the extract of roots of C. longa was done in dimethylsulphoxide. The effects of the plants on the growth of Histoplasma capsulatum var farciminosum were assessed by agar dilution assay. Culture media with no antifungal agent and media containing ketoconazole served as negative and positive control, respectively. The methanol extract of C. longa showed inhibitory effects at concentrations ranging from 0.07 to 5 mg/mL. Similarly, the methanol extract of P. dodecandra showed growth inhibitory effects at concentrations ranging from 0.156 to 5 mg/mL. That is, the growth inhibitory concentration of C. longa was 0.07 mg/mL, whereas that of P. dodecandra was 0.156 mg/mL. In contrast, D. stramonium showed no inhibitory effect. This preliminary observation showed that methanol extracts of C. longa and P. dodecandra showed inhibitory effects on the growth of Histoplasma capsulatum var farciminosum requiring further repeated in vitro evaluation so as to generate adequate evidence, which would justify in vivo trials.     

Effects of the ruminal comminution rate and microbial contamination of particles on accuracy of in situ estimates of ruminal degradability and intestinal digestibility of feedstuffs

Effects of considering the comminution rate (k_c) and the correction of microbial contamination (using ¹⁵N techniques) of particles in the rumen on estimates of ruminally undegraded fractions and their intestinal digestibility were examined generating composite samples (from rumen‐incubated residues) representative of the undegraded feed rumen outflow. The study used sunflower meal (SFM) and Italian ryegrass hay (RGH) and three rumen and duodenum cannulated wethers fed with a 40:60 RGH to concentrate diet (75 g DM/kgBW^0.75). Transit studies up to the duodenum with Yb‐SFM and Eu‐RGH marked samples showed higher k_c values (/h) in SFM than in RGH (0.577 vs. 0.0892, p = 0.034), whereas similar values occurred for the rumen passage rate (k_p). Estimates of ruminally undegraded and intestinal digestibility of all tested fractions decreased when k_c was considered and also applying microbial correction. Thus, microbial uncorrected k_p‐based proportions of intestinal digested undegraded crude protein overestimated those corrected and k_c?k_p‐based by 39% in SFM (0.146 vs. 0.105) and 761% in RGH (0.373 vs. 0.0433). Results show that both k_c and microbial contamination correction should be considered to obtain accurate in situ estimates in grasses, whereas in protein concentrates not considering k_c is an important source of error.     

Effects of oral supplementation of probiotic strains of Lactobacillus rhamnosus and Enterococcus faecium on diarrhoea events of foals in their first weeks of life

Foal first diarrhoea is one of the most prominent problems in the early life of horses. Probiotics might have the potency to prevent or at least diminish neonatal diarrhoea. We hypothesised that the treatment of foals with probiotic strains of Lactobacillus rhamnosus and Enterococcus faecium starting early after birth and then daily over 2 weeks would prevent or mitigate foal heat diarrhoea. The influence of this probiotic treatment on diarrhoea incidence and growth and health performance of young foals was investigated. Thirty‐four foals were randomly allocated to two groups. From day 1 to 14 of life, the foals received either placebo (PG, n = 16) or the probiotic treatment (TG, n = 18). Clinical examination was performed, and the faeces consistency score (FCS, 1–5; with diarrhoea defined by ≤3) was recorded once per day in weeks 1 and 2 and once weekly in weeks 3–8 of life (WL). The body height was measured at birth and after two and eight WL. Diarrhoea occurred in the 1st WL in 19% and 61% of PG and TG foals respectively. In the 1st WL, diarrhoea lasted 0.3 ± 0.8 and 1.6 ± 1.4 days in PG and TG foals respectively. In the 2nd WL, diarrhoea occurred in 94% and 84% of PG and TG foals, respectively, and lasted for 3.0 ± 1.5 and 3.7 ± 1.6 days respectively. At least two periods of diarrhoea developed in 33% and 65% of PG and TG foals respectively. The TG foals grew slightly slower than the PG foals. The results indicated that the probiotic treatment of neonatal foals as performed in this study was not suitable to reduce diarrhoea within the first two WL, because contrary to the hypothesis, the TG foals suffered more frequently and for longer periods from diarrhoea than the PG foals.