微生态制剂对草鱼生产性能和肠道菌群的影响

在水温25~30℃下,将体质量为(110.23±0.43)g的草鱼饲养在3.0 m×2.0 m×1.2 m的加盖网箱中,分别投喂添加0%(对照组)、0.5%和2%的由芽孢杆菌、乳酸菌以及酵母菌复配且以麸皮为载体制成的微生态制剂(8.0×10~9 cfu/g)的膨化饲料饲养60 d,探究微生态制剂对草鱼生产性能和肠结构、菌群及酶活性的影响。试验结果显示,饲料中添加2%微生态制剂显著提高草鱼质量增加率、特定生长率(P<0.05),显著降低饲料系数、脏体比(P<0.05);饲料中添加2%微生态制显著提高肠伸展率、中肠肌层厚度和绒毛高度(P<0.05),提高中肠淀粉酶和脂肪酶活性(P<0.05)。饲料中添加微生态制剂增加草鱼肠道菌群α多样性、丰富度;改变草鱼肠道微生物组成,门水平上,对照组的草鱼肠道微生物中梭杆菌门和厚壁菌门含量最高(63.56%、32.52%)。0.5%添加组的草鱼肠道微生物中梭杆菌门和厚壁菌门含量最高(61.82%、20.27%)。2%添加组的草鱼肠道微生物中厚壁菌门含量最高(64.20%)。属水平上,2%添加组草鱼肠道优势菌属直接发生改变,Paeniclostridium和Erysipelatoclostridium丰度大幅上升。随着微生态制剂添加量的增加,肠道微生物的代谢功能增强,组成中与无机离子转运和代谢、碳水化合物转运与代谢、氨基酸转运与代谢等功能相关的菌群丰度升高。综上可知,饲料中添加芽孢杆菌、乳酸菌以及酵母菌等组成的微生物制剂可作为生产草鱼绿色饲料的重要措施。     

Biolog-ECO方法探究饲喂益生菌对凡纳滨对虾肠道微生物代谢及有效作用时间的影响

以霍氏肠杆菌(E3)和乳酸菌(R3)2株益生菌对凡纳滨对虾进行为期4周的养殖饲喂实验,饲喂后期利用Biolog-ECO方法对实验组及空白组的凡纳滨对虾肠道微生物菌群多样性的差异进行比较分析,以评价益生菌对凡纳滨对虾肠道微生物菌群代谢功能的影响。结果显示,添加霍氏肠杆菌(E3)或乳酸菌(R3)的实验组,与空白组相比较,平均每孔颜色变化率显著上升,表明益生菌增强了肠道微生物活性;凡纳滨对虾肠道微生物利用各类碳源的整体能力显著增强,表明益生菌可以促进水产动物的代谢功能;肠道微生物多样性指数(包括Shannon、Simpson和McIntosh指数)有明显差异,表明饲喂2株益生菌可以提高凡纳滨对虾肠道菌群的丰富度。其中,停喂霍氏肠杆菌后第1天和第5天取样结果表明,Shannon指数显著降低,Simpson和McIntosh指数显著升高;停喂乳酸菌后的第1天和第5天取样结果表明,Shannon指数无显著差异,Simpson和McIntosh指数显著升高;二者在第10天取样的结果中均无显著差异,表明饲料中添加益生菌可以改变凡纳滨对虾肠道内原有菌群的数量和结构,促进对虾肠道内微生物群落间复杂的相互作用,进而在维持或者促进对虾健康方面发挥着重要的作用,同时也表明此两株益生菌在凡纳滨对虾肠道中停留时间最少为5 d。     

Effects of a probiotic mixture (Bacillus subtilis YB‐1 and Bacillus cereus YB‐2) on disease resistance and non‐specific immunity of sea cucumber,Apostichopus japonicus (Selenka)

The effect of a commercially available compound probiotics product containing Bacillus subtilis YB‐1 (50%) and Bacillus cereus YB‐2 (50%) fed to sea cucumbers, Apostichopus japonicus (Selenka) on challenge infections and non‐specific immune responses was assessed. Sea cucumbers (were randomly allocated into nine aquariums at a density of 30 sea cucumbers per tank and triplicate groups) were fed diets containing 0 (control), 10⁷ and 10¹⁰ cfu (g diet)^?1 of the probiotics mixture for 32 days. The growth factors and immunological parameters were measured. In addition, the effects on resistance against Vibrio alginolyticus infection were also evaluated. The results indicate that all the immunological parameters (phagocytic activity, superoxide anion production, lysozyme activity, catalase activity and phenoloxidase activity) measured and the growth rate of sea cucumbers fed 10¹⁰ cfu of the probiotics mixture were significantly (P < 0.05) improved than control groups at 16 and 32 days. After challenging, the cumulative mortality for the control was 100%, whereas the cumulative mortality for sea cucumbers fed 10¹⁰ cfu of the probiotics mixture was 47% (P < 0.05). Although the total autochthonous intestinal heterotrophic bacterial counts were not affected by dietary treatment (P > 0.05), Bacillus sp. levels were significantly elevated in sea cucumbers fed the probiotics mixture (P < 0.05). These results confirmed that administration of the probiotics mixture in the diet stimulated non‐specific immune responses and enhanced the growth performance of sea cucumbers, and was effective in controlling infections caused by V. alginolyticus.     

Adhesion to sole, Solea senegalensis Kaup, mucus of microorganisms isolated from farmed fish, and their interaction with Photobacterium damselae subsp. piscicida

Abstract Most studies carried out to select microorganisms as candidate probiotics have focused on in vitro antagonism tests, such as the production of inhibitory compounds against pathogenic microorganisms. However, attachment to mucous surfaces could be another criterion to be considered when selecting potential probiotics for aquaculture. Nineteen isolates obtained from farmed Senegalese sole, Solea senegalensis Kaup, and gilthead sea bream, Sparus aurata L., have been evaluated for their capacity to adhere to skin and intestinal mucus of Senegalese sole, and their antagonistic effect against Photobacterium damselae subsp. piscicida, an important pathogen for farmed sole. The isolates from gilthead sea bream showed the highest percentage of adhesion to sole mucus, whilst the pathogenic microorganisms assayed and the isolates from sole showed, in general, a lower ability to adhere to sole mucus. The results suggest that the adhesion to fish mucus was more dependent on the isolate tested than on the host mucus. The isolates from gilthead sea bream also showed a higher antagonistic activity against P. damselae subsp. piscicida than those from Senegalese sole. Four isolates were selected, on the basis of their adhesive ability and antagonistic effect on P. damselae subsp. piscicida, to study their interactions with the pathogen in respect of adhesion to skin and intestinal mucus under exclusion, competition and displacement conditions. The results obtained show the ability of three isolates to reduce the adhesion of P. damselae subsp. piscicida to sole mucus under displacement and competition conditions. The adhesion of the pathogen to sole intestinal mucus was also significantly reduced when three isolates were assayed under exclusion conditions.     

Isolation and evaluation of putative probiotic strains from different teleost to prevent Pseudomonas aeruginosa infection in Cyprinus carpio

Probiotics renowned as valuable microbes serve as a potential alternative to control diseases in aquaculture and are considered as an efficient and environment‐friendly approach to reduce the use of antibiotics. The present study aims at the isolation of putative probiotic bacteria from the intestinal tract of different fish species from the Doaba region of Punjab, India. In this study, isolated bacterial strains were characterized based on their morphological, biochemical and molecular characterization by 16S rRNA gene sequencing, followed by in vitro evaluation of different selection parameters described in FAO/WHO guidelines. A total of 169 different bacterial strains were isolated from the gastrointestinal tract of 52 different fish species. After in vitro evaluation, out of 169 bacterial strains only five bacteria (S3, S7, BDK2', BDK7 and BDK9) identified as Enterococcus and Bacillus species showed antagonistic activity against the fish pathogen Pseudomonas aeruginosa (MTCC 4 673). These isolates were screened based on their response towards bile tolerance, pH tolerance, adhesion and drug susceptibility to different antibiotic discs. And, the in vivo results indicated improved growth and survival against the infection (P. aeruginosa) after oral administration of the probiotics. The observations of in vitro and in vivo evaluation indicate that these isolated probiotic strains serve as effective probiotics and can be used as a novel and safe treatment to cure current issues in aquaculture.     

生防木霉菌株Tr10诱变改良

利用亚硝酸盐和紫外线复合诱变对生防木霉菌Tr10进行了改良。采用平板对峙法、摇瓶液体发酵法、发酵产物平板活性测定法研究了突变株的生长速度、拮抗作用、代谢产物的抑茵活性和突变株的遗传稳定性。研究结果表明.适宜诱变条件是0.01mol／L亚硝酸溶液诱变20min,然后在距20W紫外灯20cm处照射3min;遗传稳定突变株NUV147和NUV218生长速度分别是出发菌株的2倍和2.1倍,产孢量显著增加,突变株对病原菌的拮抗作用增强,拮抗机制没有变化。     

杨树林下经济效益与优化模式构建研究

通过连续监测,总结分析杨树林下经济效益并提出优化模式,结果表明:杨树林下种养模式既有良好的经济效益,又能节约林分管理成本和促进林木生长,但不同模式的适用范围和经济效益存在显著差别;适当加大株行距和宽行窄株配置能有效提高林下经济的效益.文章同时提出了适合不同立地和林分的多个杨树林下经济优化模式.     

基于模糊数学法复合茯砖茶饮料配方优化及其香气品质分析

在单因素试验考察各原料添加比例对茶饮料感官得分的影响基础上,利用Design Expert(V.10.0.4)软件最优混料设计方法,采用模糊数学法对复合茯砖茶茶饮料的色泽、香气和口感进行感官评分,优化复合茶饮料的配方.结果表明,利用软件的优化功能和验证试验得出最佳配方为:茯砖茶40.2％、龙眼干36.2％、灵芝粉15....     

益生素“绿禽康”对肉鸡生产性能的影响及防病效果

将益生素＂绿禽康＂（益生菌短短芽孢杆菌YSJ-0401活菌含量为1×109cfu/g）以不同浓度添加入饲料,当使饲料中益生菌YSJ-0401的含菌量分别为102～106cfu/g时,饲养12周后＂绿禽康＂处理组肉鸡平均体重分别为863～933g,较对照比增61～131g,比增率为7.50%～16.25% 肉鸡肉料比分别为0.50～0.57,较对照比增0.02～0.09,比增率为4.17%～18.75% 肉鸡死亡率在3.03%～12.12%之间,低于对照组18.18%,绿禽康对病鸡的防治效果分别为33.33%～83.33%。其中,＂绿禽康＂1%添加量的增重、提高肉料比和防病的效果最佳。试验初步表明：益生素＂绿禽康＂可增强肉鸡的抗病能力,提高肉鸡体重和肉料比。益生素＂绿禽康＂在肉鸡日粮中适宜添加量为1%。     

黄曲霉毒素B_1吸附菌株的筛选及吸附机理研究

为获取能够高效吸附黄曲霉毒素B1(AFB1)的益生菌,研究16株益生菌对培养基中AFB1的吸附效果。结果表明,11株菌株对AFB1具有明显的吸附效果,其中酿酒酵母Y1吸附效果最佳,对其菌体处理方式和吸附时间进行优化后,对AFB1的吸附率可达81.16%。复合物稳定性试验结果表明,Y1与AFB1通过物理方式结合,且该结合可逆。加热处理可使各菌株的AFB1吸附能力显著增强。扫描及透射电镜观察发现,加热处理后Y1菌体表面由光滑变得凹凸不平,并且其细胞壁厚度增加至原来的148.73%,与AFB1的接触面积增加,从而导致Y1对AFB1的吸附能力明显增强。