温度对鸡离体小肠磷吸收的影响研究

采用单因子随机试验,24只35日龄体重相近的三黄肉公鸡的十二指肠、空肠和回肠肠囊随机分配到4个处理中,每个处理6个重复,每个重复1个肠囊,分别在30℃、34℃、38 ℃和42℃条件下水浴振荡培养50min,探讨不同培养温度对鸡离体小肠磷吸收和肠黏膜细胞活性的影响.结果表明:培养温度在30～38℃C时,肠囊磷吸收量与温度呈正相关,38℃时肠囊的磷吸收量显著高于30℃和34℃时肠囊的磷吸收量(P＜0.05),42℃时,肠囊的磷吸收量极显著降低(P＜0.01);培养液中LDH活性与培养温度呈线性关系,培养温度在30～38 ℃时,培养液中LDH活性没有明显差异(P＞0.05),但42℃时培养液中LDH活性极显著高于其它处理(P＜0.01).结果提示:鸡离体小肠适宜的培养温度是38℃.研究为鸡小肠离体培养温度的合理选择提供依据.     

培养液磷含量和pH值对鸡离体小肠磷吸收的影响

本研究主要探讨了培养液不同pH值和磷含量对鸡离体小肠磷吸收的影响,为体外培养鸡小肠合理选择培养液pH值和用外翻肠囊法评定饲料有效磷时合理选择培养液磷浓度提供参考依据。采用2个单因子随机试验,每个因子4个处理。48只30日龄体重相近的三黄肉公鸡的十二指肠、空肠和回肠肠囊随机分配到8个处理中,每个处理6个重复,每个重复1个肠囊,39℃培养50min。结果表明：pH5．0～7．0时,肠囊的磷吸收量线性增加;pH8．0时,肠囊的磷吸收量降低;与pH5．0比较,pH7．0时,肠囊的磷吸收量极显著增加（P〈0．01）。培养液磷含量在50～200μg／mL时,肠囊的磷吸收量与磷含量呈正相关;当磷含量增加到400μg／mL,十二指肠肠囊和空肠肠囊的磷吸收量开始降低;磷吸收率与培养液磷含量之间呈负相关,不同处理之间差异极显著（P〈0．01）。结果显示：以肉仔鸡为动物模型,用外翻肠囊法评定饲料有效磷时,培养液适宜pH为6．0～7．0;有效磷含量不能超过200μg／mL,以50μg／mL左右为宜。     

仔猪小肠对二肽吸收特点的研究

本试验采用体外外翻肠囊的方法研究了等摩尔浓度的Ｌ 甘氨酸 Ｌ赖氨酸组成的二肽（Ｇｌｙ－Ｌｙｓ）和游离甘氨酸和赖氨酸混合物（Ｇｌｙ＋Ｌｙｓ）在仔猪小肠各段的吸收特点。将仔猪小肠划分为空肠前段、中段、后段和回肠段,分别在各段设置了两个不同的培养液处理组,分别是浓度为２０ｍｍｏｌ／Ｌ的Ｇｌｙ－Ｌｙｓ和Ｇｌｙ＋Ｌｙｓ混合物培养液组。每个处理３个重复（回肠段无重复）,每个重复为一个外翻肠囊,将每个外翻肠囊置１０ｍｌ培养液中培养１５分钟。旨在比较：体外培养１５分钟后,同一浓度下的Ｇｌｙ－Ｌｙｓ和Ｇｌｙ＋Ｌｙｓ在外翻肠囊各部位的吸收差别,从而确定Ｇｌｙ－Ｌｙｓ在仔猪各肠段的吸收特点。结果表明,同等摩尔浓度下,Ｇｌｙ－Ｌｙｓ组中的赖氨酸和甘氨酸在仔猪空肠中段肠组织的累积量显著大于Ｇｌｙ＋Ｌｙｓ组;从肠囊在１５分钟培养后总的氨基酸摄入量上看,Ｇｌｙ－Ｌｙｓ组的赖氨酸和甘氨酸在空肠中段高于Ｇｌｙ＋Ｌｙｓ组,且二者在赖氨酸上的差异显著。这说明,二肽中甘氨酸和赖氨酸至少在空肠中段的运输系统有别于游离态的甘氨酸和赖氨酸,且对二肽的运输显得比对游离氨基酸的运载更有效。     

深海鱼肽对肉仔鸡肠道氨基酸吸收的影响

为研究深海鱼肽对肉仔鸡肠道氨基酸(苏氨酸、甘氨酸、脯氨酸、异亮氨酸、亮氨酸、组氨酸、赖氨酸)吸收的影响,选取健康体重差异不显著的6周龄爱拔益加肉仔公鸡10只,随机分为两个处理,分别是深海鱼肽处理组和游离氨基酸处理组,每个处理5个重复.采用外翻肠囊法,将肠段进行离体培养.结果显示:在深海鱼肽系统中,7种氨基酸回肠中的总吸收高于游离氨基酸系统;对苏氨酸、甘氨酸、脯氨酸、组氨酸,深海鱼肽能很好的促进它们在小肠的吸收,且在小肠后段效果更明显;深海鱼肽系统中异亮氨酸、亮氨酸、赖氨酸的吸收相对于游离氨基酸系统要低.结果表明,深海鱼肽对不同肠段不同氨基酸作用效果不同.     

离体肉鸡小肠对纳米氧化铜吸收速率的研究

采用翻转肠囊法研究离体内鸡小肠对硫酸铜、氧化铜、纳米氧化铜的吸收速率.结果显示,在培养时间为0.5 h时,纳米氧化铜的吸收速率显著高于硫酸铜与氧化铜(P＜0.05);在1 h和1.5 h时,吸收速率纳米氧化铜高于硫酸铜与氧化铜,但三者之间差异不显著(P＞0.05);各组肠道吸收速率前段均高于后段(P＞0.05).试验表明,肉鸡小肠对纳米氧化铜的吸收速率高于硫酸铜和氧化铜.     

仔鸡外翻肠囊适宜培养时间的研究

试验旨在用乳酸脱氢酶法探讨仔鸡肠囊的最佳培养时间.采用单因素试验设计.将6只三黄公鸡的十二指肠、空肠和回肠肠囊随机分配到锥形瓶中,1只鸡为1个重复,每个肠段6个重复,然后在0,20,40,60和80 min用移液枪分别从每个锥形瓶中取100μL培养液分析乳酸脱氢酶活力.结果表明,在0～60min.培养液中乳酸脱氢酶活力上升较缓慢,60min后上升幅度较快;仔鸡肠囊的适合培养时间是40～50min.     

用外翻肠囊法研究有机锰在肉仔鸡小肠中的吸收特点

用外翻肠囊法研究肉仔鸡十二指肠、空肠和回肠对无机锰和有机锰的吸收特点。共包括2个试验，试验1是以硫酸锰为锰源，根据单位时间锰的吸收率与外翻肠囊培养时间的曲线关系确定最佳培养时间，试验2是在此培养时间下比较不同形态锰在肉仔鸡小肠中的吸收特点。2个试验均采用单因子完全随机设计。试验1培养时间分别为20、40、60和80min 4个处理组，将48只28日龄商品代AA肉公鸡随机分到4个处理组，每组6个重复，每个重复2只鸡(为了扣除内源影响，其中1只鸡作为零添加锰水平处理)，每只鸡的十二指肠、空肠和回肠分别用作相应部位肠段外翻肠囊的1个重复。在试验2中共设8个处理组，分别为：硫酸锰、甘氨酸锰螫合物、蛋氨酸锰螫合物、弱络合强度的蛋氨酸锰(Mn—Met E)、中等络合强度的氨基酸锰(Mn—AA A)和强络合强度的氨基酸锰(Mn—AA B)、硫酸锰与甘氨酸混合物及硫酸锰与蛋氨酸混合物的处理组。为了扣除内源影响，另设1组作为零添加锰水平处理。用于试验1中日龄相同的AA肉公鸡72只，随机分到9个处理组，每组8个重复，每个重复1只鸡，每只鸡的十二指肠、空肠和回肠分别用作相应部位肠段外翻肠囊的1个重复。结果表明：(1)锰的吸收率和培养时间在40min内呈线性关系，因此选择30min为试验2的培养时间；(2)体外培养回肠肠囊对无机锰的吸收率一般是十二指肠和空肠肠囊的2～6倍；(3)回肠中锰的吸收率受到添加锰源的显著影响，其中合成蛋氨酸锰组锰的吸收率明显高于硫酸锰和合成甘氨酸锰，中等和强络合强度的氨基酸锰组锰的吸收率也明显高于无机锰和合成甘氨酸锰。试验结果提示，在体外简单缓冲溶液培养的肉仔鸡小肠各段外翻肠囊中，回肠是肉仔鸡小肠吸收锰的主要部位；络合或螫合的有机态锰在体外培养的小肠外翻肠囊中的吸收率比无机形态的锰高；作为配体而言，蛋氨酸比甘氨酸更有利于促进锰的吸收。     

胆盐和游离脂肪酸影响离体小肠细胞类胡萝卜素吸收的研究

用黄鸡小肠细胞进行了 β-胡萝卜素和黄体素的体外吸收试验 ,研究类胡萝卜素浓度、胆盐和游离脂肪酸对这两种类胡萝卜素吸收的影响。结果发现 :β-胡萝卜素和黄体素的吸收均呈浓度依赖性 ;牛磺胆酸钠极显著促进黄鸡离体小肠细胞类胡萝卜素的吸收(P<0.01) ,其促进 β-胡萝卜素和黄体素吸收的最佳浓度分别为3mM和10mM ;游离脂肪酸极显著促进了类胡萝卜素的吸收(P<0.01) ,其中油酸对类胡萝卜素的促吸收作用大于硬脂酸 ,促进 β-胡萝卜素和黄体素吸收的最佳油酸/硬脂酸比率分别为100 :0和3 :1。牛磺胆酸钠和游离脂肪酸影响 β-胡萝卜素吸收的动态变化模式与它们对黄体素的显著不同     

维生素D对动物小肠无机磷吸收的影响研究

维生素D对动物小肠无机磷吸收起着重要作用.本文综述了维生素D对动物无机磷吸收的影响机制,维生素D对动物血清中Pi含量、肠道组织Na+-Pi流通速度、肠道刷状缘膜囊泡中Pi吸收速度、动物肠道Na+-Pi-IIb mRNA及Na+-Pi-IIb蛋白数量的影响.从生理和分子方面为无机磷的吸收提供理论依据.     

日粮磷水平对肉鸡磷代谢及Na/Pi-Ⅱb基因mRNA表达的影响

本论文旨在探讨不同磷水平对肉鸡磷代谢及小肠Na/Pi-Ⅱb(钠依赖Ⅱb型磷转运载体蛋白)基因mRNA表达的影响。选择60日龄体质量约1.5 kg的三黄肉鸡40只,随机分配至日粮总磷水平分别为0.4%(A组)、0.6%(B组)、0.8%(C组)和1.0%(D组)(钙∶有效磷=2∶1)的4个处理中,每个处理设5个重复,每个重复2只鸡(1个代谢笼),其中B处理为对照组。试验结果表明,血清磷随日粮磷水平提高而升高,血清钙随日粮磷水平提高而下降;日粮总磷水平在0.8%时,血清AKP活性最低,而钙磷代谢率最高;与对照组相比,较低磷(TP 0.4%)提高肉鸡空肠前段(P<0.01)和空肠后段(P>0.05)Na/Pi-Ⅱb mRNA表达水平,而高磷(TP 0.8%,TP 1.0%)则降低肉鸡十二指肠(P<0.01)、空肠段(P>0.05)Na/Pi-Ⅱb mRNA表达水平;十二指肠和空肠前段对磷的吸收率随饲粮磷水平的提高而下降,各肠段对磷的体外吸收率在较低磷(TP 0.4%)时最高。结果提示,低磷日粮条件下,提高日粮磷水平可上调Na/PiⅡ-b mRNA表达量,促进磷的吸收,日粮磷水平过高时,则抑制Na/PiⅡ-b mRN...     

紫锥菊、黄芪对法氏囊病雏鸡的肝损伤及脾脏NK细胞活性的影响

给14日龄雏鸡灌服不同浓度紫锥菊、黄芪合剂,连续灌服7d,21日龄时雏鸡接种传染性法氏囊病病毒(IB-DV),来观察雏鸡血液转氨酶活性及脾脏NK细胞活性的变化。结果显示,攻毒后4d和攻毒后11d时用药组与攻毒对照组相比,谷草转氨酶(Ast)、谷丙转氨酶(Alt)均有所降低,差异显著(P<0.05);攻毒后11d时Ast/Alt比值极显著低于攻毒对照组(P<0.01)。脾脏NK细胞活性在感染后14d,高剂量组活性极显著高于攻毒对照组和空白对照组(P<0.01),感染21d后各组差异不显著。结果表明,紫锥菊、黄芪合剂在雏鸡感染IBDV后12d前后一段时间可显著降低传染性法氏囊病病毒对肝脏造成的损伤,促进脾脏NK细胞的活性,增强机体的防御功能,有利于该疾病的防治。     

钙对成骨细胞活性、[Ca~（2＋）]_i及GJIC的影响

在体外培养4日龄SD大鼠成骨细胞（OB）的基础上,添加不同浓度钙（0、1、2、4mmol/L）,钙作用2d后,观察细胞活性、间隙连接通讯（GJIC）,测定钙离子（[Ca2＋]i）浓度;钙作用2、5、8d测定OB内总蛋白及Ⅰ型胶原（Col-Ⅰ）含量。与对照组比较,钙作用2d后,OB内线粒体增多,内质网扩张,细胞内[Ca2＋]i浓度增加,GJIC的荧光扩散距离缩小。总蛋白含量,在2d,钙1、4mmol/L组高于（P〈0.05或P〈0.01）对照组,在5、8d低于对照组,但仅在8d差异显著（P〈0.05或P〈0.01）。第2天后,钙抑制Col-Ⅰ分泌（P〈0.01）,在5、8d均促进（P〈0.05或P〈0.01）其分泌。结果表明,添加钙作用2d后,促进OB代谢及[Ca2＋]i沉积,抑制细胞间通讯,促进总蛋白分泌,抑制Col-Ⅰ分泌,促进了细胞增殖。增殖期过后,则抑制总蛋白分泌,促进Col-Ⅰ分泌,使OB较早的进入基质成熟期,利于骨骼的重建。     

Effect of sampling method and incubation temperature on fungal culture in canine sinonasal aspergillosis

O bjectives : To evaluate the most appropriate sampling procedure and the effect of incubation temperature on fungal culture in the diagnosis of canine sinonasal aspergillosis (SNA).
M ethods : Sixteen dogs with SNA and 20 dogs with non-fungal nasal disease entered a prospective study. Nasal secretions and mucosal biopsies were collected in all dogs. Fungal plaques were also sampled in dogs with SNA. Each specimen was taken in duplicate from each dog and incubated at room temperature and 37°C.
R esults : In dogs with SNA, nasal secretions, mucosal biopsies and fungal plaques yielded fungal growth at room temperature in one, one and seven dogs, respectively, whereas fungal growth was obtained at 37°C in three, 12 and 14 dogs, respectively. No specimen collected from any dog with non-fungal nasal disease yielded fungal growth at room temperature or at 37°C.
C linical S ignificance : The diagnosis of canine SNA is more likely to be confirmed following culture of mucosal biopsies or fungal plaques than nasal secretions sampled blindly with swabs. Incubating cultures at 37°C is more likely to provide a diagnostic outcome than when samples are cultured at room temperature. Fungal culture of nasal specimens has good specificity for the diagnosis of SNA in dogs.     

Effect of culture media and incubation temperature on growth of selected strains of Francisella tularensis.

The rate and amount of growth of 4 field isolates and reference strain ATCC 6223 of Francisella tularensis were evaluated on isolation media with 2 different agar bases and with different supplements and incubated at 25 C, 35 C, and 42 C. Biochemical reactions on conventional differential media with and without cysteine were evaluated. Two of the field isolates and the reference strain were F. tularensis subspecies tularensis (formerly biovar tularensis or Type A), and 2 isolates were subspecies holarctica (formerly subspecies palaearctica or Type B). Bacto cystine heart blood agar supplemented with 1% hemoglobin, glucose cystine heart blood agar, and brain-heart infusion blood agar supported good growth of all 4 field strains, with the most luxuriant growth occurring on Bacto cystine heart blood agar with hemoglobin. Heart infusion blood agar and trypticase soy blood agar supported growth of the field isolates, although growth was diminished and delayed. Strain 6223 was distinctly fastidious and failed to grow on heart infusion or trypticase soy blood agars. Growth of strain 6223 was best on Bacto cystine heart blood agar with hemoglobin. The agar base did not affect growth unless the supplements became limiting, in which case Bacto agar base generally supported growth better than BiTek agar base. Incubation at 35 C was optimum for all 5 strains. Growth at 42 C was slow, with the greatest decrease in the rate and amount of growth occurring with field isolates of F. tularensis subspecies tularensis. Strain 6223 did not grow at 25 C, and the 4 field isolates grew slowly at the lower temperature.(ABSTRACT TRUNCATED AT 250 WORDS)     

In vitro culture of equine respiratory mucosa explants

An in vitro model of the upper respiratory tract of the horse was developed to investigate mechanisms of respiratory diseases. Four tissues of the upper respiratory tract of three horses were collected. Explants were maintained in culture at an air–liquid interface for 96 h. At 0, 24, 48, 72 and 96 h of cultivation, a morphometric analysis was performed using light microscopy, scanning electron microscopy and transmission electron microscopy. The explants were judged on morphometric changes of epithelium, basement membrane and connective tissue. Viability was evaluated using a fluorescent Terminal deoxynucleotidyl transferase-mediated dUTP Nick End Labelling (TUNEL) staining. No significant changes in morphometry and viability of any of the explants were observed during cultivation. Hence, the in vitro model may be useful to study infectious and non-infectious diseases at the level of the equine respiratory tract, with potential application to the development of vaccines and treatments for diseases of the respiratory tract.     

不同供磷水平对胡麻磷素养分转运分配及其磷肥效率的影响简

 以“坝选３号”胡麻为材料,研究了不施磷、低磷、中磷和高磷４ 个不同施磷（Ｐ_２Ｏ_５）水平（０,３５,７０ 和１０５ｋｇ／ｈｍ^２）对胡麻植株中磷素累积、转运、分配和磷肥利用效率的影响。结果表明,低磷、中磷和高磷水平时,胡麻各器官不同生育阶段磷素养分吸收和累积量的基本趋势一致,但其变化量与施磷量有极大关系。胡麻地上茎、叶、非籽粒和籽粒中,磷素的日增量增幅因器官而异;胡麻只有叶片中有磷素转移,中磷处理比低磷和高磷处理磷转移量增加５４．９３％～７３．８３％和８．１９％～１０．００％（P＜０．０５）,籽粒中２０．４６％～３５．９３％ 的磷素是靠叶片转运而来。胡麻植株磷素累积主要在生殖生长阶段,占整个生育期总累积量的７９．０２％～９２．１７％。施磷（Ｐ_２Ｏ_５）量为７０ｋｇ／ｈｍ^２时磷肥表观利用率和农学效率最高,分别为２０．２２％～２０．５３％和７．３０～７．４４ｋｇ／ｋｇ。胡麻产量随施磷量增加而增加,增幅最高达２８．９６％～３１．４６％。结合产量与磷肥表观利用率和农学效率,本实验区同等肥力土壤条件下,以施磷（Ｐ_２Ｏ_５）量为７０ｋｇ／ｈｍ^２（中磷）为宜。     

Effect of dietary phosphorus content on milk production and phosphorus excretion in dairy cows

Background

Phosphorus (P) supplementation is costly and can result in excess P excretion. This study investigated the effects of reducing dietary P on milk production and P excretion in dairy cows over a full lactation.

Method

Forty-five multiparous Holstein dairy cows were divided into 15 blocks according to expected calving date and previous milk yield, and assigned randomly to one of the three dietary treatments: 0.37, 0.47, and 0.57% P (DM basis); these P levels represent the NRC recommendations, Chinese recommendations, and the amount of dietary P commonly fed by Chinese dairy farmers, respectively. Average daily feed intake was calculated from monthly data on feed offered and refused. Milk yields of individual cows were recorded weekly, and milk samples were taken for analysis of protein, fat, solids-not-fat, lactose, and somatic cell count. Blood samples were collected on days −6, −3, 0, 3, 6 relative to calving, and then monthly throughout lactation, and analyzed for P and Ca concentrations. Spot samples of feces and urine were collected for 3 consecutive d during weeks 12, 24, and 36, and P concentrations were analyzed. Reproduction and health data were recorded.

Results

Dietary P did not affect dry matter intake or milk yield (P > 0.10). Milk fat content was slightly higher in cows fed 0.37% P than in cows fed 0.47% P (P = 0.05). Serum concentrations of P and Ca did not reflect dietary P content (P > 0.10). Fecal and urinary P both declined linearly (P < 0.05) as dietary P decreased from 0.57 to 0.37%. Fecal P content was 25% less when dietary P was 0.37% compared to 0.57%. Health events and reproductive performance were not associated with dietary P content (P > 0.05).

Conclusions

Lowering dietary P from 0.57 to 0.37% did not negatively affect milk production, but did significantly reduce P excretion into environment.