微波水解制备复合氨基酸的研究

以鸡羽毛为原料,采用正交试验研究了微波水解法制备复合氨基酸的工艺条件。结果表明,影响羽毛微波水解的主要因素为固液比和硫酸浓度,而水解时间与微波功率变化影响较小。试验确定的微波水解制备复合氨基酸的优化条件为:固液比1:5、水解时间3h、硫酸浓度3mol/l、微波功率500W。微波水解法与传统水解法相比,具有水解时间短的优势。     

饲用复合酶制剂酶学特性研究

饲用复合酶制剂的主要酶种包括纤维素酶、蛋白酶、脂肪酶和淀粉酶。利用高产菌株S6-5、Y7-6和B5-12混合发酵生产复合酶制剂,发现纤维素酶催化反应最适宜的酸碱度在pH=5.0,反应体系温度为60℃时,纤维素酶活力达到14293U/g;蛋白酶酶活在pH=6.0时酶催化能力最强;而脂肪酶和淀粉酶在50℃时催化能力最强,在60℃催化能力下降,但不明显。     

山羊多头蚴及其异位寄生病例的诊治

多头蚴病俗称脑包虫病,是带科多头属多头绦虫的幼虫寄生于牛、羊脑或脊髓内发生的疾病。多头蚴的成虫寄生于狗、狼等肉食动物的小肠内,孕卵节片随粪便排出体外,从孕卵节片内释放出大量虫卵,污染饲草、饲料或饮水,牛、羊等中间宿主吞食后,六钩蚴钻人肠黏膜的毛细血管,随着血液循环带到脑和脊髓等易寄生部位,以脑部寄生为多。     

Genetic differences in oestrous signs and oestrogen metabolism‐related genes between Chinese Mi and European Landrace‐Large White pigs

Oestrous signs affect timely mating and reproductive efficiency in swine breeding herds. To study the genetic difference of oestrous signs between Chinese and European pigs, 100 Landrace‐Large White (LLW) cross gilts and 50 Chinese Mi gilts were assessed for oestrous signs and the concentrations of serum estradiol‐17β and progesterone were determined. The genotype of 39 single nucleotide polymorphisms (SNPs) in 11 oestrogen metabolism and function‐related genes was determined by Sequenom iPLEX platform. Compared with LLW gilts, Mi gilts had longer time of standing reflex (p < .001), higher scores of vulva reddening (p = .001) and greater serum estradiol‐17β concentration (p < .01). Gilts with greater serum estradiol‐17β concentrations also had greater (p < .05) scores for oestrous signs. Genetic polymorphisms of nine genes in oestrogen metabolism pathways had significant differences (p < .05) between LLW and Mi gilts. There were three and six haploblocks of SNPs in LLW and Mi, respectively. Compared with LLW, the distribution of haplotypes was more centralized in Mi pigs. Genetic polymorphisms of oestrogen metabolism‐related genes have considerable differences between Chinese Mi and European LLW pigs. Because of the important roles of oestrogen during the oestrus, some genes of oestrogen metabolism pathway could be considered as candidate genes for oestrous signs.     

维生素D_3疯狂上涨的背后

<正>1维生素D3价格的井喷也许没有多少人会想到,维生素D3———这个维生素大家族中的小品种会搅的整个饲料养殖行业如此躁动不安,突然无货可供,价格陡然飙升。2009年7月下旬,饲用级50万单位维生素D3粉的价格(下同)在50元/kg左右徘徊,虽显启动迹象,但市场关注度不高。当时有先见之明的市场人士预测,其价格可能在9月份升至300元/kg,但也     

Pharmacokinetics of oxytetracycline in hemolymph from the Chinese mitten crab, Eriocheir sinensis

Feng, Q., Wu, G. H., Liang, T. M., Ji, H. Y., Jiang, X. J., Gu, W., Wang, W. Pharmacokinetics of oxytetracycline in hemolymph from the Chinese mitten crab, Eriocheir sinensis. J. vet. Pharmacol. Therap. 34 , 51–57. The purpose of this study was to investigate the hemolymph kinetics and depuration time of oxytetracycline following intramuscular administration at doses of 2, 8 and 40 mg/kg body weight, respectively. The concentration of OTC in hemolymph was assayed using solid phase extraction and high performance liquid chromatography. The elimination half‐life of the terminal part of the elimination phase (t_1/2β) ranged from 87.9 to 114.3 h. The total body clearance (CL_b) was 0.0430 L/kg/h at the lower dose, 0.0123 L/kg/h at the medium dose and 0.0013 L/kg/h at the higher dose. The apparent volume of the central compartment (V_c) was found to be 1.383, 0.699 and 0.143 L/kg respectively. The depuration time for each dose was 13.6, 29.6 and 57.6 days, respectively. Results from the present study suggest that the 40 mg/kg dose might have the best therapeutic efficacy following intramuscular administration.     

沙拉沙星对大鼠生殖毒性和致畸性的研究

本文报道沙拉沙星对Wistar大鼠生殖毒性和致畸性的研究，在孕鼠妊娠经7－15d，分别经口灌服5、50和500mg/kg b.w.剂量沙拉沙星溶液。试验结果显示，沙拉沙星对孕鼠的健康状况、行为和增重均无明显影响；各剂量组受孕鼠的活胎数、死胎数和吸收胎数均无明显影响；除500mg/kg b.w.剂量组胎鼠的体长明显低于对照组外，各组间的胎鼠体重、体长、尾长和胎盘重均未见明显差异；各剂量组和对照组均未出现外观畸形和内脏畸形，仅500mg/kg b.w.剂量组胎鼠的骨骼畸形出现率（36.3%）显著高于对照组（8.7%），但不存在剂量－反应关系。作者认为沙拉沙星对Wistar大鼠无明显的生殖毒性和致畸性。     

自动进排料密闭式固态发酵罐的设计

为解决当前固态发酵劳动强度大,生产效率低的问题,设计内置纵向排列带扇形缺口的浅盘组和升降旋转控制刮板的中心轴来实现自动进排料和翻料的固态发酵罐,可实现自动化生产,原位灭菌,提高生产效率。     

阿拉善荒漠区主要盐生植物水势日变化

以内蒙古阿拉善盟荒漠区的代表性盐生植物胡杨(Populus euphratica)、柽柳(Tamarix ramosissima)、梭梭(Haloxylom ammodendron)、沙枣(Elaeagnus angustifolia)和小叶杨(P.simonii)等5种优势植物为研究对象,对其叶片水势的日变化进行了测...     

Eimeria tenella搭载科学卫星对虫体生物学特性影响的初探

为探讨微重力与太空辐射等因素对鸡球虫生物学特性的影响，我们首次将一株已孢化的柔嫩艾美耳球虫搭载于返回式科学试验卫星。卫星运行７天后返回地面。