Screening of gastrointestinal bacteria of Indian major carps for a candidate probiotic species for aquaculture practices

Probotic selection could be detrimental for the success of aquaculture practices. While, in most of the cases emphasis is given to the production of antibacterial compounds, and in vitro inhibitory activities of a bacterium for choosing a probiotic strain, however, other criteria like non‐antibiotic resistant, non‐haemolytic nature and non‐pathogenic potentiality of probiotic strain are often overlooked. We have screened gastrointestinal bacteria isolated from all the three species of Indian major carps viz., Labeo rohita, Catla catla and Cirrhinus mrigala for a suitable probiotic. Bacteria like Aeromonas (Aeromonas species, A. hydrophila), Micrococcus, Corynebacterium, Plesiomonas, Bacillus (Bacillus species, B. subtilis) and Pseudomonas (Pseudomonas species, P. aeruginosa) exhibited antibacterial activities against different pathogens. Among these, B. subtilis was found to grow at a wider range of temperatures, pH and salt concentrations and was non‐haemolytic, non‐antibiotic resistant, non‐pathogenic and inhibited all the tested primary and secondary pathogens. Dietary supplementation of the bacteria at 10⁸ CFU g^?1 feed also enhanced the growth of Indian major carp, L. rohita. Based upon these characteristics, we aimed to develop a suitable probiotic for aquaculture practices.     

Dietary microorganism and plant effects on the survival and immune response of Litopenaeus vannamei challenged with the white spot syndrome virus

The effect of plants and probiotics on the survival and immune response of Litopenaeus vannamei challenged with the white spot syndrome virus (WSSV) was evaluated. A probiotic mixture (PM), plant extract (PE) or powdered plants (PP) were added to feed with the attractant Dry Oil^®. An experiment was conducted with five treatments in triplicate. Shrimp (weighing 11.70±2.5 g) were cultured in 120 L plastic tanks and fed twice a day with commercial feed plus additives or with commercial feed plus WSSV. Animals were monitored for the occurrence of WSSV using single‐step and nested PCR. The PM and PP added to the commercial feed showed high survival, a decrease in WSSV prevalence in shrimp and an increase in the activity of lysosomal enzymes, N‐acetyl‐β‐glucosaminidase and acid phosphatase. The total haemocyte count in shrimp treated with PM was significantly higher than that in the control group (treatment I) and in shrimp fed with PE. The results of the present work indicate that PP and PM are good candidates for use as feed additives against WSSV in shrimp cultures.     

一株嗜盐光合菌的分离及对养殖污水的处理效果

以海南虾池特殊生境底泥为菌源,富集、分离出一株嗜盐光合菌,命名HPSB2,并对其进行形态学观察、特征峰值测定及生理生化检测.结果显示:其与红环菌科(Rhodocychceae)索氏菌属(Thauera)特性相似,16SrDNA序列比对显示与Thauera aminoaromatica和Thauera mechemich...     

Carnobacterium maltaromaticum vs. Vibrio (Listonella) anguillarum in the midgut of Atlantic cod (Gadus morhua L.): an ex vivo study

The present investigation addresses whether the midgut (MG) of Atlantic cod (Gadus morhua L.) is an infection route for Vibrio (Listonella) anguillarum serotype 02 β and if Carnobacterium maltaromaticum, a probiotic bacterium, can out‐compete the pathogen and modulate the autochthonous MG microbiota. This was investigated by using an ex vivo method the intestinal sac, utilized previously in studies on Atlantic cod and Atlantic salmon (Salmo salar L.). Exposure of the MG to V. (L.) anguillarum did not reveal any cell damage indicating that the MG does not appear to be an infection route for V. (L.) anguillarum in healthy Atlantic cod. This finding together with previous observations on Atlantic cod and Atlantic salmon indicate that intestine as an infection route might vary between these two species. When the MG was exposed to C. maltaromaticum, no cell damage or cellular disruptions were observed. As budding from the apices of microvilli was observed in all treatments exposed to bacteria, we suggest that budding might be involved in the primary barrier against bacterial infection. However, to clarify this hypothesis, further studies are needed. Exposure of the MG to the probiotics and pathogenic bacteria indicated that C. maltaromaticum, to some extent, is able to out‐compete V. (L.) anguillarum but the topic merits further investigation. Analysis of the MG microbiota after sterile saline solution and bacterial exposure indicates that bacteria related to Staphylococcus sciuri belong to the autochthonous gut microbiota in Atlantic cod.     

益生菌治疗奶牛乳腺炎的研究进展

乳腺炎是影响奶牛生产性能及健康最常见、最严重的疾病之一,可以导致奶牛淘汰、养殖场（户）经济损失。该病常用抗生素治疗,但易产生耐药性,畜产品存在抗生素残留,不利于奶牛养殖业绿色健康发展。益生菌具有增强奶牛免疫力、降低发病率和改善生产性能的优势,可替代抗生素,有良好的应用价值。本文对奶牛乳腺炎危害、益生菌有益作用和替代抗生素治疗的潜质进行综述,推动奶牛养殖业绿色、健康发展。     

蔬菜复合可溶性膳食纤维酶法提取及抗氧化活性研究

以西蓝花、苦瓜、金针菇、魔芋4种蔬菜为试验原料,通过正交优化研究复合酶法提取复合可溶性膳食纤维的最佳工艺参数,并对提取所得的可溶性膳食纤维的抗氧化活性进行了比较研究。结果表明,复合酶法提取蔬菜复合可溶性膳食纤维最佳工艺为淀粉酶、蛋白酶、糖化酶最适添加量分别为200、1250、25 U/g,最佳提取温度分别为90、45、60℃,最佳酶解时间均为60 min。在此条件下,可溶性膳食纤维的提取得率可达4.97%。体外抗氧化试验表明:四种蔬菜的复合可溶性膳食纤维具有一定的体外抗氧化作用,且与浓度呈正相关,在浓度为3 mg/mL时,对DPPH自由基、·OH自由基的清除率分别为82.42%和57.97%,均高于金针菇、苦瓜、魔芋、西蓝花这4种蔬菜单一提取的可溶性膳食纤维。本试验为蔬菜复合可溶性膳食纤维的提取及综合利用提供了一定的指导。     

复配种衣剂对豌豆生长及产量的影响

选用亮盾（杀菌种衣剂）、高巧（杀虫种衣剂,间接防治病毒病）和凯普克（植物生长调节剂）3种药剂进行复配,对甜豌3号、绿宝、宝峰6号和食荚大菜豌1号等4个菜豌豆品种进行种子包衣,根据出苗率、主要农艺性状和产量表现等,研究确定最佳药种比。结果表明,药种比为1∶0.5时,甜豌3号和绿宝出苗受抑制;药种比为1∶7.5时,出苗率、农艺性状和产量无显著变化;药种比为1∶5.0时出苗率最高,幼苗长势最好,平均产量比对照增加20.5%。因此,复配种衣剂处理豌豆种子的最佳配比是：亮盾10mL、高巧20mL和凯普克10mL混匀包衣5.0kg豌豆种子。     

益生菌微胶囊包埋方式的研究进展

益生菌可以改善人体肠道菌群、提升肠道健康水平,但经过胃酸和胆汁的作用后,进入肠道活性降低,无法发挥其作用。通过不同壁材制备的微胶囊对益生菌进行包埋,可对益生菌起到较好的保护作用。综述不同的包埋壁材形成的单层、双层和三层结构的特点,总结不同包埋结构的优缺点,并从包埋原料、设备和工艺3个方面对未来益生菌的微胶囊包埋进行了展望。     

Prevalence of a fish pathogen, Listonella anguillarum, in the intestinal tract of fish collected off the coast of Japan

This study evaluates the influence of temperature manipulation on circulating levels of sex steroids and gonadal maturation in F1 generation Senegalese sole Solea senegalensis breeders kept under either continuous light (LL) or natural photoperiod (NP). Under LL, progressive water temperature reduction during early winter [treatment MT (modified temperature)] significantly elevated [compared with exposure to LL and constant temperature (CT)] plasma steroid levels in females (January–February) and males (January) and proportion of females initiating maturation (January), suggesting a modulatory role of decreasing temperature in the early phases of sole gonadal recrudescence. Under NP, treatment MT did not stimulate female gonadal maturation despite the significantly higher plasma testosterone levels (February) compared with exposure to NP and CT, which may indicate that females at early‐intermediate phases of ovarian development, the predominant stages of maturation at early winter, were less responsive to the treatment. Conversely, treatment MT significantly enhanced male androgen production from January onwards, together with an increase in proportions of running individuals (March), indicating that males were also responsive to this treatment at mid‐late phases of testicular development. Our data further support the strong influence of water temperature on the overall control of gonadal maturation in Senegalese sole.     

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。