马铃薯渣酶法水解液制备单细胞蛋白饲料的研究

本文研究了酶法水解马铃薯渣制备膳食纤维后的滤液制备单细胞蛋白的可行性。试验结果表明,单细胞蛋白边糖化边发酵的摇瓶培养的较优工艺条件为:底物浓度为8%(添加8%的麸皮水)、初始pH值为4.5、接种量为15%、葡萄糖淀粉酶加入量为100U/g(原料中淀粉)、青霉素加入量为80U/g(原料)、培养温度为28℃、培养时间为6h、转速为250r/min。在此条件下,干酵母产量最高为19.920g/L,单细胞蛋白中的蛋白质含量达12.27%。     

饲粮中添加抗菌肽对肉鸭增重及血清尿素氮、总蛋白水平的影响

240只1日龄肉鸭随机成分4组,每组设3个重复,对照组用基础日粮,试验组在基础日粮上每千克分别添加1、2、3mL抗菌肽制剂。结果显示:1)2、3mL/kg添加量组增重效果显著(P<0.05),3mL/kg添加量组最佳;净肉率升高,达到显著水平(P<0.05),其中主要是胸肌率上升;腹脂率降低但差异不显著(P>0.05);料重比无显著变化(P>0.05)。2)血清总蛋白浓度差异不显著(P>0.05),但尿素氮浓度下降,2、3mL/kg添加量组达显著水平(P<0.05),3mL/kg添加量组最低。     

反刍动物肽营养研究进展

本文综述了反刍动物肽的吸收特点及影响因素,肽的吸收代谢机制,肽对瘤胃微生物的调控及对反刍动物生产性能发挥的作用,以及饲料蛋白源活性肽的开发应用。     

酵母蛋白饲料培养条件的研究

对啤酒酵母进行发酵试验,结果表明:该酵母最优的培养条件是麦芽汁培养基稀释倍数2.5,培养时间20h,蔗糖添加量10Brix,尿素添加量0.02%,且酵母菌耐酸耐铜的性能好。     

哺乳犊牛的消化特点与蛋白质需要

本文从犊牛的消化生理特点出发,综述了犊牛出生后的生理特征及蛋白质、必需氨基酸的需要量,并对代乳品中蛋白质原料进行了论述。     

TOTAL ANOMALOUS PULMONARY VENOUS CONNECTION IN A FOAL

An 8-day-old Arabian-Morgan cross colt underwent cardiac evaluation. The foal was tachycardic, tachypneic, exercise intolerant and had a loud right-sided heart murmur and cyanotic mucous membranes. Total anomalous pulmonary venous connection was diagnosed with echocardiography and confirmed at postmortem examination. Total anomalous pulmonary venous connection is a very rare congenital cardiac abnormality that has not been reported before in the horse.     

Role of p38MAPK in production of pro-inflammatory cytokines in Kupffer cells from severe acute pancreatitis rats

AIM:To investigate the role of p38 mitogen-activated protein kinase (p38MAPK) signaling pathway in the Kupffer cells (KCs) production of pro-inflammatory cytokines, tumor necrosis factor-α(TNF-α) and interleukin-1β(IL-1β), in severe acute pancreatitis (SAP) rats.METHODS:Sprague-Dwaley rats were randomized into three groups:①sham operation rats, ②SAP rats, ③SAP rats given the p38 MAPK inhibitor CNI-1493(10 mg/kg, iv). The SAP model was induced by the bili-pancreatic duct infusion with 5% sterile soduim taurocholate solution. Rats from each group were killed at 12 h after sham operation or SAP and Kupffer cells (KCs) were isolated. The mRNA expressions of TNF-α and IL-1β (by quantitative real-time RT-PCR) and p38 MAPK activity (by Western blot analysis) in KCs were examined. The levels of TNF-α and IL-1β in plasma were determined by ELISA.RESULTS:There was a significant acvitation of p38 MAPK in KCs harvested from SAP rats than those from sham operation rats. SAP also promoted the mRNA expressions of TNF-α and IL-1β in KCs and the plasma levels of TNF-α and IL-1β. These events were significantly inhibited by treatment with CNI-1493.CONCLUSIONS:p38 MAPK activation is one important aspect of the signaling events that may mediate the KCs production of pro-inflammatory cytokines, TNF-α and IL-1β, in SAP rats. The inhibition of the p38 MAPK may be a potential target in the prevention and treatment of SAP.     

Quick detection of sex determining region protein gene in mouse fetuses

AIM: To detect quickly the Y-chromosome specific sex determining region protein (Sry) gene in mouse fetuses on embryonic day 14.5 with a PCR method. METHODS: We designed specific primers with the OLIGO 5. 0 software. Templates were prepared in 30 minutes by the following way. About 1 mg embryonic tissue but not fetal liver was suspended, and treated with 200μL of lysis buffer, consisting of PCR buffer containing 20 mg/L proteinase K, 0. 5% NP-40, and 0.05% Tween 40, at 60°C for 15 minutes, heated for 5 minutes at 100 °C, 10μL was used as template. The PCR react ion was performed in 50μL, using two sets of primers specific for Sry gene (chromosome Y) and IL-3 gene (chromosome 11) . PCR conditions and cycle numbers were optimized. The assessment of the results was done by electrophoresis in 3% agarose run at high voltage. The specificity of the method was conf irmed by fluorescent in situ hybridization (FISH) using a specific male probe on embryonic tissue cells. RESULTS: Electrophoresis showed that PCR product of male control DNA consisted of a 649 bp product representing the IL-3 gene and a 444 bp product representing the Y-specific Sry gene, female control DNA only one 649 bp product. Fetuses with two bands matching those as seen inmale control DNA are the presumpt ive male fetuses. Fetuses, only the IL-3-associated 649 bp band, are the presumptive female fetuses. These were confirmed by FISH. The ent ire procedure took <3. 5 h. CONCLUSION: The established PCR assay offers a quick, simple, accurate, and sensitive detection of sex determining region protein gene in mouse fetuses. This method allowed the preparation and culture of pure male and female hematopoietic stem cells from fetal tissue.     

Rat urotensin-II-induced main pulmonary artery contractions are mediated by MAPK

AIM: To investigate rat Urotensin-II(rat U-II)-induced vasoconstriction of rat main pulmonary arteries and the role of mitogen-activated protein kinase(MAPK). METHODS: The main pulmonary artery was dissected from the male Sprague-Dawley rats and artery ring width was 3-4 mm. Concentration-response curves were generated to rat U-II(0.03 nmol/L-30 nmol/L).Inhibitor of MAPK, PD 98059(0.1 μmol/L-10 μmol/L) were added into the medium after rat U-II(30 nmol/L)induced vasoconstriction had reached plateau to construct the relaxant concentration-response curves and their EC₅₀ and E_max. RESULTS：Rat U-II was a potent vasoconstrictor of isolated rat main pulmonary arteries [EC₅₀=7.95±0.40, E_max=(14.28±6.34)% of the response to 60 mmol/L KCl]; PD 98059 caused concentration-dependent relaxations of rat U-II precontracted arteries [EC₅₀=5.91±0.45, E_max=(81.39±13.65)%]. CONCLUSION: Rat U-II was a potent vasoconstrictor of rat main pulmonary arteries and this response was mediated through MAPK.     

Whole-Cell Fatty Acid Composition to Characterize and Differentiate Isolates of Rhizoctonia Species Associated with Turfgrass Diseases in Japan

Cellular fatty acids were analyzed to characterize and differentiate 34 isolates of Rhizoctonia species representing binucleate Rhizoctonia AG-D (I), AG-D (II), R. solani AG 2-2 IIIB, AG 2-2 LP, R. circinata var. circinata and var. oryzae associated with turfgrass diseases in Japan. Myristic, pentadecanoic, palmitic, palmitoleic, stearic, oleic, linoleic and linolenic acids were consistently present in varying quantities in all isolates. Heptadecanoic and 9-heptadecenoic acids were present in isolates of Rhizoctonia AG-D (I), AG-D (II), R. solani AG 2-2 IIIB and AG 2-2 LP but not in isolates of R. circinata var. circinata and var. oryzae. Palmitic, oleic and linoleic acids were the major fatty acids found, constituting 88.30-98.37% of the whole-cell fatty acid content. The remaining fatty acids were present in smaller amounts. Isolates within a single group were closely clustered, whereas isolates from different groups were clearly distinguishable based on average linkage cluster analysis of cellular fatty acids. Principal component analysis, based on all fatty acids detected, confirmed the distinct separation of isolates representing the six groups of Rhizoctonia species obtained from turfgrasses. These results suggested that fatty acid analysis is useful for the characterization and differentiation of isolates of Rhizoctonia species associated with turfgrass diseases. Received 21 May 2001/ Accepted in revised form 28 September 2001