Effects of aflatoxin B1 on mitochondrial respiration,ROS generation and apoptosis in broiler cardiomyocytes

Aflatoxin B1 (AFB1) develops various toxic effects in the liver by impairing mitochondrial function, inducing cell apoptosis. However, little is focused on its toxicity to broiler cardiomyocytes (BCMs). Here, the mitochondrial membrane potential (MMP), reactive oxygen species (ROS) generation, cardiac troponin T (cTnT) location, apoptosis induced by AFB1, and antioxidative genes were investigated in BCMs. It was found that AFB1 evoked intracellular ROS generation, and induced apoptosis in BCMs. AFB1 treatment resulted in increased percentage of apoptotic cells, increased location range of cTnT in cytoplasm, upregulated messenger RNA (mRNA) expression of nuclear factor erythroid 2‐related factor 2 (Nrf2) and downregulated mRNA expressions of Mn‐superoxide dismutase in BCMs. These findings suggested AFB1 treatment caused significant cardiomyocyte damage and cardiotoxicity, impairment of mitochondrial functions, activated ROS generation, and induced apoptosis, and probably was involved in the Nrf2 signal pathway in BCMs.     

黄曲霉毒素B_1致雏鸭肝脏细胞DNA的损伤效应

【目的】(1)研究黄曲霉毒素B1(AFB1)不同染毒水平(3,30,300μg·kg-1BW)染毒后,在不同时间点导致雏鸭肝细胞DNA损伤情况;(2)探明AFB1染毒剂量及染毒时间与雏鸭肝细胞DNA损伤之间的关系,为AFB1遗传毒性提供研究模型。【方法】96只雄性北京鸭雏鸭,随机分为16组,每组6只。第1组为对照组,第2至6组为低剂量(染毒)组、第7至11组为中剂量(染毒)组、第12至16组为高剂量(染毒)组。对照组、低剂量组、中剂量组、高剂量组雏鸭分别灌胃25%DMSO水溶液,0.25,2.5,25μg·mL-1溶液各1mL,对照组于灌胃1h后,各剂量染毒组分别于灌胃染毒1、2、8、24、48h用彗星试验检测肝细胞DNA损伤。【结果】试验表明,雏鸭对于AFB1导致的肝细胞DNA损伤非常敏感,肝细胞DNA损伤程度与AFB1摄入量以及摄入时间有关。经口染毒2h左右DNA损伤达到高峰,所有染毒组在尾长、尾部DNA百分含量、尾矩、Olive尾矩等指标上均显著高于对照组(P0.05);随着AFB1染毒剂量增加,DNA损伤程度加深、持续时间延长。【结论】(1)AFB1致雏鸭肝细胞DNA损伤的效应非常强,低剂量(3μg·kg-1BW)AFB1暴露就能够引起雏鸭肝细胞DNA发生显著损伤。(2)经口染毒AFB12h后雏鸭肝细胞DNA损伤达到高峰,此时DNA损伤程度与AFB1暴露之间的量效关系最为明显。(3)雏鸭是研究AFB1遗传毒性的一个良好动物模型,彗星试验能够反映AFB1致雏鸭肝细胞DNA损伤的量效关系。     

一株黄曲霉拮抗菌的筛选、鉴定及特性研究

为获得拮抗黄曲霉和降解黄曲霉毒素的生物防治菌株,以烟台黄曲霉污染区域土壤为材料,采用稀释分离法和琼脂扩散法,筛选到一株对黄曲霉有抑制作用且可降解黄曲霉毒素的菌株Y-17-3。根据菌株的形态学特征、生理生化试验结合16S rDNA基因序列分析和系统发育树构建,确定菌株 Y-17-3 为空气芽孢杆菌(Bacillus aerius)。该菌株发酵液经硫酸铵沉淀的抗菌活性及稳定性试验,发现70%饱和硫酸铵沉淀的蛋白粗提物抑制黄曲霉活性最强,可降低黄曲霉孢子的萌发率,抑制菌丝的生长和菌丝球的形成,且该蛋白粗提物对温度、pH值和蛋白酶敏感。菌株Y-17-3能够降解黄曲霉毒素B₁,培养6 d时的降解率达90%。综上,所分离的空气芽孢杆菌Y-17-3菌株能够通过产生拮抗蛋白来抑制黄曲霉生长,且具有较强的黄曲霉毒素降解能力,在农业生物防治领域具有一定的应用前景。     

Groundnut (Arachis hypogaea L.) improvement in sub-Saharan Africa: a review

Groundnut (Arachis hypogaea L.) is a multi-purpose legume crop widely cultivated in sub-Saharan Africa (SSA). However, yield levels of the crop has remained relatively low in SSA owing to a range of biotic, abiotic and socio-economic constraints. A dedicated groundnut improvement programme integrating new tools and methodologies to breed varieties suitable for current and emerging agro-ecologies and market needs is essential for enhanced and sustainable groundnut production in SSA. The objective of this review is to highlight breeding progress, opportunities and challenges on groundnut improvement with regard to cultivar development and deployment in SSA in order to guide future improvement of the crop. The review analysed the role of new tools in breeding such as, high-throughput and automated phenotyping techniques, rapid generation advancement, single seed descent approach, marker-assisted selection, genomic selection, next-generation sequencing, genetic engineering and genome editing for accelerated breeding and cultivar development of groundnut.     

AFB1 Bio-Degradation by a New Strain - Stenotrophomonas. sp

The paper was to find the bacteria to degrade aflatoxin B 1 （AFB 1） and realize the application of biological degradation on AFB 1. Using cumarin as the carbon source and energy on the first screening, then the ten strains which were first screened out were taken to degrade AFB 1 100 pg kg^-1. Strain NMO-3 was screened out of ten strains, the degradation ratio of AFB 1 reached 85.7%, which was more prominent than the others （P 〈 0.01）. With the analysis of colony morphology, physiological and biochemistry experiments, and 16S rDNA gene sequence, the strain NMO-3 was finally identified as Stenotrophomonas sp. Using cumarin as the carbon source and energy could screen out the AFB 1 degradation strains. Acute toxicity tests show that the viable number of NMO-3 lower than 3.12 × 10^10 cfu mL-1 is safety. The crude enzyme was obtained by 65% ammonium sulfate fractionation, and it could degrade AFB1. It is the first report for the strain＇s detoxi- AFB1.     

加热对花生黄曲霉毒素含量的影响

将花生在不同加热温度和时间下进行加热,测定黄曲霉毒素(AFT)在不同温度及时间下的含量。结果表明,加热可降低花生中的黄曲霉毒素的含量,并随温度升高和加热时间的增加,毒素含量也明显下降。同时毒素含量的减少速率与样品最初被污染水平有关,AFTG1的热稳定性较AFTB1差。     

黄曲霉毒素对猪生长性能及内脏器官的影响

选用60头体质量28 kg左右的杜长大三元杂交猪,随机分为2组,每组3个重复,每个重复10头猪(公母各半),分别饲喂基础日粮(C组)、基础日粮添加0.1 mg/kg黄曲霉毒素(AF组),试验期90 d,研究黄曲霉毒素(AF)对猪生长性能及内脏器官的影响。结果表明:AF显著影响试验猪的生长性能和内脏器官相对重量,与C组相比,AF组试验猪日增重降低了12.90%(P<0.01),料重比提高了7.54%(P<0.01);AF组试验猪肝脏、肾脏、脾脏、胰脏的相对重量分别提高了8.24%(P<0.05)、27.27%(P<0.01)、41.18%(P<0.01)、42.86%(P<0.01);AF组试验猪肝细胞和肾细胞发生了严重的脂肪变性和空泡变性。提示:长期饲喂0.1 mg/kg黄曲霉毒素污染的日粮可诱发猪黄曲霉毒素的慢性中毒。     

酸活化坡缕石对肉鸡日粮中黄曲霉毒素B1的去毒效果

480只1日龄艾维因商品代肉鸡，按饲养试验要求分为4组：基础日粮组(对照组)；I．基础日粮 0.25％活化坡缕石组；Ⅱ．霉变玉米50％代替基础日粮中的玉米组，使黄曲霉毒素B1前期为97μg／kg，后期为108μg／kg；Ⅲ，第1组日粮 0．25％活化坡缕石组。研究了酸活化坡缕石对肉鸡日粮中黄曲霉素B1的去毒作用。结果表明，与对照组相比，添加0．25％活化坡缕石对肉鸡生长性能、内脏器官相对重量、血清生化指标和免疫指标均无显著影响，而霉变玉米可使肉鸡生长性能显著降低，肝脏率、心脏率、肾脏率、腺胃率、谷草转氨酶、谷丙转氨酶、碱性磷酸酶、谷胱甘肽硫转移酶活性显著提高，血清中IgG、IgA、C3、C4显著降低；联合饲喂霉变玉米／活化坡缕石可使肉鸡生长性能、内脏器官相对重量、血清生化指标和免疫指标均恢复至对照组水平。上述结果提示，活化坡缕石对肉鸡日粮中黄曲霉毒素B1具有较好的去毒作用。     

Lactobacillus plantarum BS22 promotes gut microbial homeostasis in broiler chickens exposed to aflatoxin B1

Probiotics promote the health of the host by maintaining intestinal microbial homeostasis. This study aimed to investigate the benefits of Lactobacillus plantarum BS22 (LP) in the gastrointestinal tract (GIT) microbial homeostasis of broiler chickens exposed to aflatoxin B₁ using the PCR‐DGGE, viable count and real‐time PCR. The toxin adsorption experiment demonstrated that treatment R5 (1.0 × 10⁸ CFU/g LP) exhibited good absorptive effect in adsorbing the aflatoxin B₁ (AFB₁) in vitro. DGGE showed that the composition and structure of gut microbiota were more similar in the mucosa than in the content of all the samples. In addition, higher diversity of the microbiota was observed in the caecum and glandular stomach than in other segments. Lactobacillus, Enterococcus and Enterobacteriaceae were more abundant in the ileum than in the other segments. Enterobacteriaceae in groups I (basal diet) and II (basal diet+50 μg/kg AFB₁) showed a significant difference in group III (basal diet + 50 μg/kg AFB₁ + 1 × 10⁸ CFU/g LP) in the crop content and duodenum mucosa (p < .05). This investigation indicates that the L. plantarum BS22 promotes GIT microbial homeostasis in broiler chickens exposed to AFB₁, particularly for the intestine mucosa microbiota. Thus, L. plantarum BS22 is a possible candidate for degrading AFB_1.     

Impact of BSE on Livestock Production System

A total of 240 unvaccinated day-old broiler chicks, which had been found to be negative for antibodies against FAV-4, were divided into four groups of 60 chicks each. Group A was fed aflatoxin at 1 ppm from 7 days to 7 weeks of age. Group V was infected intra-abdominally at 14 days of age with 0.2 ml of FAV-4, having a titre of 10^5.5 TCID₅₀ per 0.2 ml. The combined group AV was given the aflatoxin and infected with FAV-4. The fourth group C served as the control. More pronounced clinical signs, a higher mortality rate (56.7%), and reductions in body weight gain and in the organ to body weight ratios of the bursa and spleen were recorded in group AV. A significant (p<0.01) reduction in the HI antibody titre following vaccination against Newcastle disease, and of skin thickness in the delayed hypersensitivity test following sensitization with DNCB, indicated an additive immunosuppressive effect from aflatoxin and FAV-4 on the humoral and cell-mediated immune responses in group AV compared to groups A and V. Microscopically, marked depletion and degeneration of lymphocytes in the thymus, bursa, spleen and caecal tonsils were observed in group AV up to 5 weeks PI.