镁在家禽中的营养作用及研究进展

镁在细胞代谢及骨骼发育过程中发挥很重要的作用。在体内,镁与钙、磷的代谢密切相关,所以在家禽日粮中添加适宜的钙、磷、镁非常重要。家禽镁元素需要量的研究很少,多数研究报告发表于35年前。尽管以植物为基础的日粮含大量镁元素,在生长阶段肉禽日粮中额外添加镁对禽肉品质和体增重仍有积极效应。而这种添加不能过量,否则会通过各种机制影响钙、磷的利用和代谢。了解日粮中添加镁对其他养分代谢、利用的影响及添加镁的副作用将有助于更好地配制平衡日粮,并保证家禽最佳的生产性能,反之亦然。因此,现将家禽镁营养的研究作一综述,探寻镁缺乏的问题。     

奶牛中镁元素吸收的定量预测

本研究的目的是在现有数据的基础上预测奶牛对镁元素的吸收。我们收集了来自15个不同研究的68种日粮和323头奶牛的平衡数据。其中12个研究采用粗饲料为主要的粗饲料来源;此外,约有一半的试验日粮采用氧化镁作为镁元素的补充形式。在68种日粮中,其中14种以碳酸氢钾、2种以氯化钾形式补充钾元素。钾元素的含量是6.9~75.6 g/kg干物质(平均29.4 g/kg干物质)。大多数研究(10/15)采用干奶期、非怀孕的奶牛作为试验动物。对泌乳期奶牛而言,产奶量处于4~22 kg/d(平均产奶量是15kg/d)的范围。所有研究都提供了镁元素和钾元素的定量吸收、以及镁元素在粪中的残留的相关数据。从这些数据可以看出,日粮镁的平均含量是4.5 g/kg干物质,含量范围为0.45~17.3 g/kg干物质。镁的平均吸收率是26.2%,范围为9.9~73.7%。日粮中钾元素浓度的不同可以部分解释镁吸收率的差异。0.31%单位/g K可以显著降低镁的吸收。K对Mg的吸收具有拮抗作用,当日粮中的K含量每增加10 g/kg干物质,镁摄入必需增加4 g/d才能保持稳定的镁吸收量。     

镁对蛋壳质量有重要影响

镁对蛋壳质量有重要影响产蛋鸡日粮中钙和磷的含量对蛋壳质量有举足轻重的作用，这是人所共知的，那么微量元素又怎样呢？据美国佛罗里达大学的研究人员报道，对４８周龄来航母鸡，按蛋壳轻重分组，日粮中均不添加铁、铜和锌，经过１０周之后，产蛋性能和蛋壳重量并无显著...     

高盐日粮诱发羔羊尿结石的试验研究

在自由饮水条件下给未阉割的雄性绵羊羔羊饲喂高磷和高镁组合日粮。经过1个月的饲喂后,对照组表现正常,并无尿石症相关症状出现;试验组在饲喂后期逐渐表现出尿结石的相关症状,血液中镁和磷的浓度也出现显著升高,尿液中尿沉渣出现增多且晶体形态与鸟粪石晶型相同。对出现尿闭的羔羊解剖后检出了尿结石,经测定其成分以磷和镁为主。试验结果表明,单纯饲喂添加高磷和高镁组合日粮可以诱导未阉割的雄性绵羊羔羊产生尿结石,且尿结石的形成与日粮中磷和镁元素的含量过高相关。     

鸡镁缺乏症预防要点

<正>镁缺乏症主要是由于日粮中镁含量不足引起的,是以雏鸡生长障碍、惊厥为特征的疾病。镁是糖代谢所需,可激活许多酶,2/3的碳酸镁存在于骨中,0.4%在蛋壳中。1)病因。日粮中镁含量不足。2)主要症状。雏鸡缺镁表现生长缓慢,直至生长停止,震颤,昏睡,骨灰分减少。受到惊吓时,患禽发生短暂的惊厥,伴同喘气,随后发生昏迷,有时出现死亡。     

日粮钙水平对老龄母鸡蛋品质的影响

本文研究了日粮中不同钙水平对老龄母鸡蛋品质的影响.选取60周龄宁都黄鸡600只,按照体重随机分为3个处理组,各组均采用豆粕-玉米基础型日粮,在日粮中添加不同水平的石粉,使日粮钙水平分别为3.0％、3.25％和3.5％,分析测定平均蛋重、蛋壳强度、蛋黄色泽、蛋壳厚度、蛋黄重以及蛋壳中钙、磷和氮含量.结果表明,随着日粮钙水平的提高,鸡蛋蛋壳强度、蛋黄重量、蛋壳中钙氮比均有所提高,以3.25％的钙水平为最适添加量.     

丁酸梭菌对产蛋后期汶上芦花鸡生产性能和蛋品质的影响

本试验旨在研究丁酸梭菌对汶上芦花鸡产蛋后期生产性能和蛋品质的影响。选用120只体重相近的330日龄汶上芦花鸡,分为5组,每组4个重复,每个重复6只鸡,自由采食和饮水。对照组只饲喂基础日粮,复合益生菌组在基础日粮中添加复合益生菌;3个水平的丁酸梭菌组(CB组)在基础日粮中分别添加1×10~7CFU/kg、1×10~8CFU/kg、1×10~9CFU/kg丁酸梭菌。试验期8周,比较分析生产性能和蛋品质。结果显示,在试验开始的第2周,10~8CB组的蛋黄指数显著高于对照组(P<0.05);在试验开始的第6周,丁酸梭菌3个处理组蛋壳指数均显著高于对照组(P<0.05),10~9CB组蛋壳强度与对照组相比显著增加;在试验开始的第8周,10~7CB组哈氏单位和蛋白高度以及蛋黄颜色均显著高于对照组(P<0.05),但丁酸梭菌对产蛋后期汶上芦花鸡产蛋率、平均蛋重、蛋壳厚度及蛋壳重量无显著影响(P>0.05)。综上结果,饲粮中添加丁酸梭菌有助于提高产蛋后期汶上芦花鸡鸡蛋品质,提高蛋禽经济效益。     

蛋禽不能喂羊骨粉

在养羊较多的地方 ,人们常常把羊骨加工成羊骨粉 ,添加到畜禽饲料中 ,代替其他骨粉。这对于大多数畜禽而言 ,是可以的 ,效果也不错。但是 ,对蛋禽就不行了。因为蛋禽所产的蛋 ,蛋壳在禽体内形成时 ,要求温度不宜过高。而羊骨粉属热性 ,在被禽体吸收利用参与蛋壳形成时 ,禽体内的温度会升高。这不仅会影响蛋壳的形成 ,而且会降低产蛋率。因此 ,蛋禽不能喂羊骨粉蛋禽不能喂羊骨粉@戎平     

油脂在蛋禽生产中应用研究进展

油脂是动物重要的能量来源,是良好的脂溶性营养物质载体,能够参与机体的多种生命活动,在动物生产中的应用较为广泛。随着养殖业规模化程度的提高,多种油脂被广泛应用于动物饲粮中以提高养殖业生产效益。文章综述了饲粮中添加油脂在蛋禽生产中的应用研究进展,介绍了蛋禽脂肪消化吸收特点及油脂对蛋禽的营养作用,并讨论了饲粮中添加不同种类及不同水平的油脂对蛋禽产蛋性能、蛋品质、蛋中营养物质和蛋禽健康的影响,为油脂在蛋禽饲粮中的高效应用提供参考。     

影响蛋壳品质的日粮因素:微量元素与添加剂

本文概述了近期关于蛋壳品质影响因素的研究进展,特别是微量元素及添加剂方面的研究,总结和探讨了日粮钙、磷及维生素D3的水平和来源对蛋壳品质影响的研究成果。近年来,关于营养对蛋壳指数影响的多数研究主要集中在日粮中微量元素的水平及来源,而饲料添加剂对肠道健康及矿物质利用率的影响也越来越受到关注。产蛋鸡日粮中添加剂和微量元素利用的研究结果并不一致。多项研究发现,一定条件下,日粮锰的水平及锰的存在形式,还有其他添加剂如预混剂、益生菌、有机酸及中草药提取物等,对蛋壳品质有显著的影响。     

商会自治的基石——商会自治规范研究

在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

猪毛色遗传的研究进展

本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.     

不同样本商品蜂蜜中硒含量的测定

用硝酸和高氯酸消化蜂蜜,使硒游离出来,在微酸性环境下,硒和2,3-二氨基萘(DAN)生成有较强荧光的物质,用环己烷萃取,在激发波长378nm,荧光波长518nm处测定其荧光强度。蜂蜜中硒含量范围:0.10～0.82μg/g。表明:蜂蜜应视为天然富硒营养品。     

乳酸杆菌益生作用机制的研究进展

乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分（表面蛋白、脂磷壁酸和肽聚糖）与肠道受体（Ｃ型凝集素受体、Ｔｏｌｌ样受体和 Ｎｏｄ样受体）,阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.     

Mechanism of Action of Probiotic Function of Lactobacilli

乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制.     

Evaluation of serum concentrations of biomarkers of skeletal metabolism and results of radiography as indicators of severity of osteochondrosis in foals

OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis.