Screening and investigation Lactobacillius spp. to improve Secale cereale silage quality

Silage is a high‐moisture‐content forage that is used to feed livestock. Using silage as feed is economically feasible and suitable for cattle management. Secale cereale is considered as a high‐quality forage plant. After the heading stage the biomass of S. cereale increases by up to 30%; however, lignification in the cell wall causes low fermentation efficiency and coefficient digestibility, and it may also be contaminated by mycotoxin‐producing fungi and can impair the quality of the silage. Therefore, the aim of this study was to screen beneficial Lactobacillius spp. for S. cereale silage to reduce fungi contamination and to increase fibrinolytic ability in the silage. Up to 100 days fermentation period and total 180 lactic acid bacteria were isolated and only a single isolate, R4‐26, showed strong acidification ability and antifungal activities against mycotoxin‐producing fungus. According to quantitative RT‐PCR results, the mycotoxin‐producing fungal contamination was significantly reduced in the S. cereale silage containing the R4‐26 isolate. In enzymatic assays, only a single isolate, R48‐27 demonstrated cellulase, xylanase, chitinase and esterase activities. In conclusion, the beneficial Lactobacillius spp. strains have the ability to reduce mycotoxigenic fungi contamination and increase fibrinolytic activity to improve quality of the S. cereale silage.     

玉米赤霉烯酮检测方法研究现状

玉米赤霉烯酮是一种常见的饲料霉菌毒素,是世界范围内污染农作物最严重的霉菌毒素之一.当畜禽采食了被玉米赤霉烯酮污染的饲料后,会对机体造成生殖毒性、肝肾毒性、细胞毒性、免疫毒性,甚至还可在机体组织中残留,通过动物性食品危及人类的健康,所以,精准的检测出饲料及饲料原料和食品中玉米赤霉烯酮毒素含量,对于保证食品安全具有重要的意...     

Saccharomyces Cerevisae and Arabidopsis Thaliana: Useful Model Systems for the Identification of Molecular Mechanisms Involved in Resistance of Plants to Toxins

Secondary metabolites produced by pathogens during the infection process are thought to play a role as pathogenicity or virulence determinants in many plant diseases. Baker's yeast and the plant Arabidopsis thaliana are attractive models for elucidating molecular mechanisms of resistance to toxic substances. For the Fusarium mycotoxin deoxynivalenol, the following resistance mechanisms were identified in yeast: (1) reduced toxin uptake due to the ABC transporter protein Pdr5p (molecular efflux pump), (2) detoxification by the acetyltransferase Ayt1p, and (3) modification of the ribosomal target by amino acid changes in the ribosomal protein L3 (Rpl3p). PDR5-like genes exist in plant genomes as large gene families and could play an important role as a first line of defence against a broad range of toxic metabolites. Amino acid alterations in the highly conserved RPL3 genes could likewise play a role in trichothecene resistance in plants. The knowledge obtained using model systems should be valuable in biotechnological approaches to disease control and marker-assisted resistance breeding.     

Role of Deoxynivalenol in Aggressiveness of Fusarium graminearum and F. culmorum and in Resistance to Fusarium Head Blight

The data available indicate that aggressiveness of Fusarium graminearum and F. culmorum depends on their deoxynivalenol (DON) and nivalenol-producing capacity: toxin-producing ability correlated closely with the level of aggressiveness measured. This agrees well with other literature findings. However, the resistance of a cultivar influenced DON production significantly. In the most resistant genotypes, toxin contamination remained near zero, whereas the same isolates and inoculum produced very high toxin levels in susceptible cultivars. As toxin levels were correlated with the ratio of Fusarium-damaged kernels (FDK) and this ratio is very low in highly resistant cultivars, the conclusion is that the level of resistance level is more important in governing DON accumulation in a given cultivar than is the aggressiveness of an isolate. In susceptible cultivars, DON producing ability is decisive, but in highly resistant cultivars resistance is the major factor in suppressing disease development and DON accumulation. In different years, the same FDK values were associated with different DON concentrations and this depended very much on the precipitation towards the end of May, the time of inoculation.     

Natural occurrence of citrinin in rice grains and its biocontrol byTrichoderma hamatum

Paddy rice was sampled from El-Sharkia, El-Gharbia, El-Dakahlia and Kafr El-Shekh governorates, Egypt. Of the 30 samples taken, ten were contaminated with the mycotoxin citrinin. An average of 6.79 × 10⁴ fungal spores per gram rice was found. The isolated fungi represented 47 species and 28 genera. The predominant genera wereAspergillus, Cladosporium andPenicillium. Aspergilli were represented by 22 species;Aspergillus niger andA. flavus had the highest occurrence.Penicillium viridicatum produced the highest amount of citrinin on glucose ammonium nitrate salts broth and rice grains, and hence this isolate was selected as a good producer of citrinin in this study. The presence ofTrichoderma hamatum reduced the amount of citrinin produced byP. viridicatum compared with its respective control. The excessive growth ofT. hamatum onP. viridicatum was increased with time. Viability ofP. viridicatum conidia decreased byT. hamatum with an increase in the incubation period. Chitinases and 1,3-β-glucanase enzyme activity ofT. hamatum increased with extending the incubation period onP. viridicatum mycelia up to maximum values at 72 and 84 h, respectively.T. hamatum led to a decrease in the production of citrinin byP. viridicatum on rice grains compared with the respective control values. http://www.phytoparasitica.org posting Dec. 19, 2004.     

镰刀菌毒素对断奶仔猪的抗营养效应及葡配甘露聚糖吸附剂的保护作用

选择125头始重(8.04±0.64)kg去势约×荣仔猪,采用2×2+1因子设计,研究被镰刀菌毒素自然污染的玉米以25%和50%的比例等量替换基础饲粮中的正常玉米并在此基础上加或不加葡配甘露聚糖(EGM)霉菌毒素吸附剂霉可吸TM对断奶仔猪生产性能、养分利用率的影响。结果表明:饲喂被镰刀菌毒素污染的饲粮降低了仔猪的生产性能,随霉变玉米替代比例增加,采食量和日增重降低程度增加(P<0.05或P<0.01);显著或极显著降低仔猪饲粮中有机物质、蛋白质、钙、磷的表观消化率(P<0.05或P<0.01)和蛋白质生物学价值(P<0.05),25%污染玉米饲粮对钙的表观消化率无影响(P>0.05);在被镰刀菌毒素污染饲粮中添加0.2%EGM吸附剂可使上述不良效应得到改善,尤以在25%污染玉米饲粮中添加0.2%EGM吸附剂可获得显著的保护效应。     

饲料中霉菌毒素的检测方法研究

饲料被霉菌毒素污染会导致营养价值降低,引起动物疾病,并直接或间接地危害人类健康,应当建立相应的体系对其监控.饲料中霉菌毒素的检测方法主要有酶联免疫吸附法(ELISA)、荧光检测法(FLD)、近红外光谱法(NIR)、薄层色谱法(TLC)、气相色谱及气相色谱-质谱联用法(GC、GC-MS)和高效液相色谱及高效液相色谱-质谱联用法(HPLC、HPLC-MS/MS)等.综述了霉菌毒素常见检测方法的研究进展和应用.     

蛋鸡饲料中有毒有害物质研究进展

饲料作为动物营养的主要来源,其安全性关乎动物健康和人类食品安全.然而饲料在生产、加工、贮存、运输等过程中可能污染有毒有害物质,并通过食物链在畜禽体内富集,最终进入人类体内,危害人体健康.现代社会人们对食品安全关注度日益增强,为畜禽提供绿色、健康、无污染的饲料,确保畜禽产品的卫生安全已成为重要的研究方向.文章简要概述蛋鸡...     

柑橘褐斑病菌毒素研究进展

本文从链格孢菌毒素种类,柑橘褐斑病菌毒素化学结构,生物活性,产毒遗传背景及致病机理等方面对毒素进行了综述,以便更好地了解该毒素,为防治链格孢菌提供理论依据。