微生物宏基因组学及其在瘤胃微生物研究中的应用

宏基因组学可以在非实验室纯培养的条件下直接获取环境微生物DNA,并对其基因组进行分析,将其克隆到合适的载体上,筛选所需要功能基因。就微生物宏基因组学及其在瘤胃微生物研究中的应用作一综述。     

Evaluation of innate immune responses in bovine forestomachs

Previous studies had indicated an active role of bovine forestomachs in the response to alimentary disorders as well as to inflammatory and infectious processes in both the gastro-intestinal (GI) tract and elsewhere. We investigated the potential of bovine forestomachs to receive, elaborate and produce signals and mediators of the innate immune response. Indeed, we detected the expression of Toll IL-1R8/single Ig IL-1-related receptor (TIR8/SIGIRR) and other receptors and cytokines, such as Toll-like receptor (TLR)4, interleukin (IL)-1β, IL-10 and Caspase-1 in the forestomach walls of healthy cows. Their presence suggests an active role of forestomachs in inflammatory disorders of the GI tract and other body compartments. Moreover, interferon (IFN)-γ was revealed in ruminal content. We confirmed and further characterized the presence of leukocytes in the rumen fluids. In particular, T-, B-lymphocytes and myeloid lineage cells were detected in the ruminal content of both rumen-fistulated heifers and diseased cows. An acidogenic diet based on daily supplements of maize was shown to inhibit leukocyte accumulation, as opposed to a control, hay-based diet, with or without a soy flour (protein) supplement. On the whole, results indicate that bovine forestomachs can receive and elaborate signals for the immune cells infiltrating the rumen content or other organs. Forestomachs can thus participate in a cross-talk with the lymphoid tissues in the oral cavity and promote regulatory actions at both regional and systemic levels; these might include the control of dry matter intake as a function of fundamental metabolic requirements of ruminants.     

Nutritive defaunation of the rumen in steers with subsequent refaunation using a cryopreserved monoculture of Entodinium caudatum

This study evaluated a technique for the nutritive defaunation of the rumen of cattle with subsequent single species refaunation using a cryopreserved monoculture of Entodinium caudatum (family Ophryoscolecidae). Four mature steers were nutritionally defaunated in two periods using two steers in each period. A diet containing (dry matter basis) 68% ground wheat grain, 7% wheat bran, 8% soybean oil and 17% wheat straw was used to decrease the pH of ruminal contents and to eliminate rumen ciliate protozoa. Protozoa‐free rumens were observed on day 8 and 9 in the first and second period, respectively, after the start of defaunation. A monoculture of E. caudatum (34/89/94) was transported from the Institute of Animal Physiology, Slovak Academy of Sciences in Ko?ice to the University of Kiel (Germany) in liquid nitrogen in October 1996. The inoculation was accomplished on day 15 in the second period by applying 30 ml culture medium with a monoculture of E. caudatum (34/89/94; average concentration of protozoal cells 2 650/ml) into the rumen of a defaunated steer via the ruminal fistula. The mono‐faunated steer was successfully inoculated with an average concentration of E. caudatum cells at 4.1 × 10³/ml (SD = 0.2) on day 2 after the inoculation.     

奶牛瘤胃积食的不同治疗方法及效果

本文对瘤胃积食的不同治疗方法及效果进行了统计分析,发现中西医结合治疗效果达到87.5%,显示高于纯中医50%和纯西医60%.     

全混合日粮中饲草长度对奶牛采食行为、瘤胃发酵和日粮消化率的影响

[目的]本研究旨在探讨奶牛TMR中,粗饲料羊草长度对奶牛采食行为、瘤胃发酵和日粮消化率的影响.［方法］试验动物为3头体重496士23 kg,安装有永久性瘤胃瘘管的健康中国荷斯坦奶牛.采用3×3拉丁方设计.用36% NDF不同羊草长度（9 cm、5 cm和1 cm）的三种全混合日粮饲喂奶牛.［结果］:①奶牛DMI和NDFI不受羊草长度影响;采食、反刍和总咀嚼时间随着羊草长度的减小显著减少.②羊草长度为1 cm时瘤胃pH显著低于9 cm和5 cm组;瘤胃内NH3-N浓度在5 cm组最高,与1 cm组差异明显;随着羊草长度减小,乙酸浓度和乙酸与丙酸的比例显著降低,丙酸浓度升高,总VFA和丁酸浓度不受羊草长度影响.③日粮中DM、CP、NDF和ADF消化率在羊草长度为5 cm时显著高于其他两组.表明饲草长度的减小会缩短采食、反刍和咀嚼时间,但过短会使瘤胃pH显著降低;适当长度可提高日粮营养成分的消化率.［结论］综合评价本试验结果以羊草长度为5 cm更适合全混合日粮配制.     

Abomasal bacteria produce an inhibitor of gastrin secretion in vitro

Previously, proliferating microflora transferred with abomasal nematodes, were suspected to be the source of the gastrin inhibitor in some parasite excretory/secretory products. Aerobic cultures in HBSS of abomasal fluid from uninfected sheep became inhibitory during the static growth phase, unless antibiotics were present. Basal gastrin secretion was reduced by up to 90%. Rumen fluid and incubates and medium in which Streptococcus bovis and ovine rumen Actinomycete spp. had been grown also contained the inhibitor. Unlike abomasal cultures, rumen fluid and incubates also reduced the measurement of gastrin standards. Rumen incubates were less potent after exposure to pH 2-3, suggesting that inactivation normally occurs in the unparasitised abomasum. Contaminating bacteria which generate the gastrin inhibitor in parasite ES products are probably rumen organisms which survive in the abomasum and proliferate during subsequent incubation. Significantly, rumen bacteria have been shown to be capable of affecting the secretory activity of the gastric mucosa.     

不同日粮蛋白质水平下梅花鹿瘤胃消化代谢参数的变化规律

选用 4头装置永久性瘤胃瘘管的成年梅花鹿 ,用 3种含有不同蛋白质水平的精料补充日粮 ,按 4× 3拉丁方试验设计 ,对瘤胃的 pH值、氨态氮 (NH3-N)、三氯乙酸沉淀蛋白(TCA -P)和总挥发性脂肪酸 (TVFA)浓度进行了测定 ,并研究了它们的动态变化规律以及VFA组分百分率     

体外产气法评定反刍家畜饲草料营养价值的研究前景

阐述了体外产气法的原理、影响体外产气量的因素及其研究前景。     

反刍动物过瘤胃蛋白的保护措施

过瘤胃蛋白就是将一些蛋白质经过处理，避免在瘤胃内被发酵、降解，而直接进入小肠后再被消化吸收，从而达到提高饲料蛋白质利用率的目的。保护饲料蛋白免遭微生物过量降解，提高蛋白质的总体利用率的方法有许多，主要有物理方法、化学方法、生物学调控、瘤胃外流速度的调控、利用食管沟反射提高过瘤胃蛋白等。本文就目前蛋白质的各种过瘤胃保护途径和效果进行了综述。