Assessment of the ochratoxin A production ability of Aspergillus tubingensis

Aspergillus tubingensis is a black Aspergillus frequently isolated from different agricultural products, including grapes. Conflicting results have been published in recent years about its ability to produce ochratoxin A (OTA), a potent nephrotoxic and carcinogenic mycotoxin. This study re-examined six A. tubingensis strains deposited in international culture collections for OTA production. OTA could not be detected in any A. tubingensis extract using HPLC coupled with a fluorescence detector (FLD), whereas it was easily detected in ochratoxigenic A. niger extracts used as positive control. The same outcome was obtained using LC-MS. The presence of other metabolites with retention times similar to the OTA signal in the A. tubingensis extracts or background noise of the growth media may be reasons for the misinterpretation of the chromatograms obtained by HPLC-FLD.     

饲养方式对新疆多浪羊肉品质的影响

分别以戈壁滩放养及工厂集约化饲养的6 月龄多浪羊背最长肌为对象,分析测定不同饲养条件下羊肉的屠 宰性能、pH值、持水力、嫩度、色泽、抗氧化能力、脂肪酸含量、肌原纤维超微结构等指标。结果表明：工厂集 约化饲养组多浪羊肉的嫩度、成熟7 d的亮度值和脂肪酸总量优于戈壁滩放养组（P＜0.05）,而戈壁滩放养组多浪 羊肉的持水力、抗氧化能力、宰后1 d的红度值及多不饱和脂肪酸含量优于工厂集约化饲养组（P＜0.05）;工厂集 约化饲养组多浪羊肉肌原纤维密度较大、直径小,肌原纤维之间排列紧密;而戈壁滩放养组的多浪羊肉肌原纤维密 度小、直径大,肌原纤维之间空隙较大。两种饲养方式各有优势,在生产中可考虑结合已有的饲养条件加以完善, 以生产出更优质的羊肉。     

冬荪液体深层培养不同时期胞外代谢物研究

为探究冬荪液体深层培养不同时期代谢物动态变化及其关系,基于液体深层培养技术,超高效液相色谱-串联飞行时间质谱联用技术研究了不同发酵时间菌丝体分泌物差异情况.结果表明,534种差异代谢物隶属于有机酸及衍生物、有机氧化合物、苯丙素和聚酮类化合物等13个不同化学类别,有机酸类化合物占比为17.978％是发酵环境成酸性的主要原...     

Effect of organic growing systems on sensory quality and chemical composition of tomatoes

Tomato plants were grown in the greenhouse in the soil, in confined beds, or in combined beds where the roots could also develop in the soil outside the bed. The beds were filled with compost based on clover grass hay, deep litter and peat and harvested in early summer and autumn in 2002 and 2003, and in the soil treatment the same compost was incorporated into the soil. The tomato fruit quality was assessed by sensory analysis and content of chemical components as, e.g. dry matter, soluble solids, citric acids and volatile components. The content of minerals was mainly determined to evaluate possible limitations in nutrient supply. Due to only minor effects of growing systems on sensory quality and chemical composition of tomato fruits it is concluded that it is possible to produce tomato fruits in confined and combined soil bed systems without any loss in eating quality. Actually the results indicate that a slight increase in quality of tomatoes from the confined and combined systems is obtained. The present result points to the fact that confined and combined growing systems may be new relevant commercial growing systems, in which the quality of tomatoes seems to be ensured, and in which nutrient loss and root diseases contamination can be reduced.     

葡萄籽提取物原花青素对肉兔抗氧化功能、脂质含量及血清代谢产物浓度的影响

研究葡萄籽提取物原花青素(grape seed proanthocyanidin extracts,GSPE)对肉兔抗氧化功能、脂质含量及血清代谢产物浓度的影响。采用单因子随机区组试验设计,选择128只60日龄、体重相近的健康新西兰兔,随机分为4组(1个对照组和3个试验组),每组32个重复,每个重复1只。对照组饲喂基础饲粮,3个试验组分别饲喂在基础饲粮中添加100、200及400 mg/kg GSPE的试验饲粮。试验期为39 d,其中预试期为6 d,正试期为33 d。结果表明:随饲粮中GSPE添加量升高,试验兔背最长肌、肝脏及血清总抗氧化能力、总超氧化物歧化酶与谷胱甘肽过氧化物酶活性均显著(P0.05)或极显著(P0.01)升高,而丙二醛浓度极显著(P0.01)降低;对照组试验兔背最长肌粗脂肪含量极显著(P0.01)高于200 mg/kg组和400 mg/kg组,而肝脏粗脂肪含量、血清三酰甘油与总胆固醇浓度均显著(P0.05)或极显著(P0.01)高于其余3组;对照组试验兔血清葡萄糖与尿素氮浓度均显著(P0.05)或极显著(P0.01)高于其余3组,而尿酸浓度显著(P0.05)或极显著(P0.01)低于200 mg/kg组和400 mg/kg组。研究结果提示:饲粮添加GSPE,可增强肉兔机体抗氧化功能,改善脂质、糖和氮代谢,且作用效果随添加量升高而增强。     

Lameness and lying behavior in grazing dairy cows

Lameness is a serious welfare issue for dairy cows. To date, the majority of studies have focused on its effect on health and behavior at the herd level. The objectives of this study were to identify (1) between-cow and (2) within-cow changes in lying behavior associated with consistent and changing lameness status in grazing dairy cows. Previous studies of lying behavior in grazing dairy cows have not considered the effect of precipitation, so a third aim was to determine the effect of precipitation on lying behavior. A total of 252 dairy cows from 6 pasture-based farms in southern Brazil were gait scored weekly to assess lameness using a 5-point scale [1–5, numerical rating score (NRS)] for 4 consecutive weeks. Cows were considered to have consistent lameness if they were scored as lame (NRS ≥3) on each of the 4 visits and considered to have a changing lameness status if scored as being nonlame (NRS <3) on at least 1 of the 4 visits. Cows classified as having a changing lameness status were further classified as developed, recovered, or inconsistent. Lying behavior (daily lying time, mean lying bout duration, and daily number of lying bouts) was recorded continuously for 3 wk using leg-mounted accelerometers. Cow-level variables included parity, days in milk, and body condition score. Regional precipitation and temperature were recorded hourly. Because only 1 primiparous cow was identified as lame at each of the 4 visits, the between-cow analysis of lameness was run on multiparous cows only. The overall prevalence of clinical lameness on the first visit was 39%, with development and recovery rates of 16 and 10% over the 4 visits, respectively. The between-cow effect of consistent lameness status on daily lying time and number of lying bouts was dependent on precipitation; consistently lame cows had reduced lying time and lying bouts on days with rain compared with days without rain. There was no within-cow effect of changing lameness status on any of the lying behaviors. Precipitation was associated with decreased daily lying time, increased mean lying bout duration, and decreased daily number of lying bouts. The results of this research provide the first evidence that the effect of consistent lameness status on lying behavior is associated with rainfall in grazing dairy cows. Future work measuring lying behavior of grazing dairy cows should include precipitation as a covariate.