Production of diatom–bacteria biofilm isolated from Seriola lalandi cultures for aquaculture application

Controlled incorporation of selected microalgae and bacteria in aquaculture systems can be beneficial because they can act as microbiological control. That is why the characteristics of biofilm generated naturally in Seriola lalandi culture cages were analysed, their potential benefit to the growth of larvae was studied, and their controlled use for improving the larval viability and as a vector to improve incorporation of previously studied probiotic bacteria was tested. According to biodiversity results, these biofilms are composed of a diatom–bacteria mix showing a decrease in biodiversity in laboratory culture conditions being dominated by Navicula phyllepta and bacteria of the family Rhodobacteraceae. This can be produced on mesh substrates incorporated in bioreactors with rapid growth rate and adhesiveness. Preliminary results from the addition of substrates with this specific biofilm in larvae culture systems showed that it is consumed by the larvae without negative effects, while positive effects on the viability of larvae in combination with probiotics were observed. Considering preliminary results, the addition of these specific substrates with diatom–bacteria biofilms could be a good improvement for aquaculture systems and together with the use of probiotics can contribute to maintaining a stable and controlled system improving the viability of the larval fish culture in its early stages.     

Effect of combined use of Bacillus and molasses on microbial communities in shrimp cultural enclosure systems

To assess the effect of addition of probiotics and carbon source on the microbial community structure within the shrimp culture, an enclosure system simulating a high density, intensive aquaculture of Litopenaeus vannamei was set up in Dianbai, Maoming, Guangdong province, China. The phylogenetic profiles of microbial communities in the enclosure system after addition of Bacillus and molasses were studied in the middle and final culture season (on the 45th, 75th and 95th day) using polymerase chain reaction‐denaturing gradient gel electrophoresis. A total of four groups, each containing a triplicate were set up: Group A (control), Group B (64% of daily feed was provided as molasses with Bacillus sp.), Group C (50% of daily feed amount provided as molasses with Bacillus sp.) and Group D (64% of daily feed amount as molasses alone). The results showed that α‐Proteobacteria, δ‐Proteobacteria, Bacteroidetes and Actinobacteria were the dominant bacteria. Moreover, the relative proportion of α‐Proteobacteria increased and that of Bacteroidetes decreased gradually with time. Pathogenic Flexibacter was the dominant genus in Group A on the 45th day, while the functional strains (Sphingomonas sp., Erythrobacter sp., Roseobacter sp., and Rhodobacter sp.) were detected multiple times in Groups B and C. Bacillus sp. was the cultivable, dominant bacterium in Groups B and C on the 95th day. Therefore, the combined use of Bacillus and molasses helped increase diversity of the microbial community, effectively inhibit pathogens, and promote the formation and development of a beneficial microbial community structure in the high density, intensive aquaculture of L. vannamei.     

A review of intestinal microbes in grass carp Ctenopharyngodon idellus (Valenciennes)

Grass carp, Ctenopharyngodon idellus, harbours complex intestinal bacterial communities, which are important in several physiological processes of their host. Intestinal microbiota of grass carp have been previously described in numerous studies. However, an overview on the bacterial community diversity, including their establishment, their functions in host's nutritional processes and immune‐related responses, and use as probiotics, is absent. This study aimed to summarize the current understanding of the grass carp intestinal microbiota. In this review, we provide general information on the establishment and composition of intestinal microbial communities and factors influencing the diversity of gut microbiota. Also, this review covers the dietary effects of probiotics, prebiotics and/or synbiotics on the grass carp intestinal microbial communities and physiological characteristics. Although our knowledge of the grass carp intestinal microbiota is expanding rapidly, further studies on the factors affecting the diversity of intestinal microbes, interactions between intestinal microbiota and their hosts and application of probiotics/prebiotics/synbiotics in aquaculture industry, are needed.     

60Coγ射线与EMS对小麦近等基因系TcLr10的复合诱变

为获得60Coγ射线与EMS对小麦近等基因系TcLr10的复合诱变体系,研究以小麦抗叶锈近等基因系为材料,应用60Coγ射线进行辐照并用EMS溶液进行处理,对小麦的发芽率、三叶期、致死率及抗病性进行分析。结果表明,本试验所用的诱变剂量对小麦近等基因的发芽率影响不显著。所用处理中到达三叶期的时间基本相同,但三叶期到四叶期的时间却随着浓度的增加而减少。当辐照剂量达到或大于0.15 kGy时,致死率显著增加。在EMS浓度为0.4%,60Coγ射线辐照剂量为0.15 kGy时,得到了3株小麦抗叶锈病近等基因系的突变体所得最佳诱变组合为EMS浓度为0.4%,60Coγ射线辐照剂量0.15 kGy。     

越桔大豆多肽复合保健饮料的加工技术研究

探讨了越桔果汁、大豆多肽溶液、绵白糖、蜂蜜、苹果酸、稳定剂等原辅料用量对产品风味及稳定性的影响,研制出越桔大豆多肽复合饮料.饮料配方经正交试验结果表明:大豆蛋白多肽溶液30%,越桔果汁9%,绵白糖9%,苹果酸0.03%,蜂蜜1.5%时风味最好.饮料的稳定性处理采用黄原胶0.08%,羧甲基纤维素钠(CMC)0.1%混合使用最为理想.     

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。     

帽儿山复层异龄天然林的林龄结构

应用地统计理论和数学模拟分析方法,对经过人工抚育和未经过人工抚育的复层异龄天然林林龄结构及树木胸径与林龄的关系、林木总的林分分布类型与种群林龄分布进行了分析探讨。结果表明:经过人工抚育的天然林在林龄结构上更具有优越性。而林木数量、林分密度上均要低于未经过人工抚育的天然林,并且在幼苗数量上明显高过未经抚育的天然林。     

4种复混肥料在含山县马肝田水稻产区推广的可行性分析

[目的]分析4种复混肥在含山县马肝田水稻产区推广与应用的可行性。[方法]通过小区对比试验,研究农家福40%BB肥、农家福45%BB肥、地泉有机无机肥、绿都有机无机肥4种复混肥在含山县马肝田水稻生产中的施用效果、增产幅度及经济效益。[结果]参试的4种复混肥对水稻有明显的增产效果,水稻平均株高、单株有效穗数、穗长、单株分蘖数和产量均高于不施肥处理。4种复混肥对水稻生育期都有明显的促进作用,产投比在1.52~2.51,高于不施肥处理,且施用有机无机复混肥的经济效益较好。[结论]参试的4种复混肥可在含山县马肝田水稻产区大面积推广应用。     

复合型饲料添加因素研究述评

[目的]探究复合型饲料添加因素分析及发展前景。[方法]综述当前复合型饲料添加剂主要复配的酶制剂、微生物、矿物质、中草药的种类与特点,作用机制,探讨复合型饲料添加剂中的酶、微生物在饲料加工和保存的稳定性及饲料酶测定方面问题。[结果]饲料添加剂从单一的酶制剂、微生物、矿物质、天然植物发展到用2种或2种以上复配成1种安全、高效、无毒副作用的绿色饲料添加剂。成分添加既能提高饲料的利用率,也能提高禽畜的免疫力、生产率,减少氮、磷的排泄量。[结论]该文为复合型饲料添加剂的应用与发展提供了依据。     

中药成分复方对兔外周血淋巴细胞增殖、IFN-γ和IL-10的mRNA表达以及兔出血症疫苗免疫效果的影响

【目的】研究两个中药成分复方（cCHMIs）的免疫增强作用和机理。【方法】选择黄芪多糖、淫羊藿多糖、蜂胶黄酮和人参皂苷4种中药成分组成两个复方,用MTT法和荧光定量RT-PCR法测定它们对兔外周血淋巴细胞增殖和IFN-γ、IL-10 mRNA的表达影响;并将两个复方作为佐剂,配合兔出血症疫苗免疫幼兔,以铝胶苗和无佐剂苗为对照,分别于免疫后7、14、21、35、49 d用MTT法和血凝抑制法测定外周血淋巴细胞增殖和血清抗体的动态变化,于免疫后63 d测定免疫器官指数和攻毒保护率。【结果】两个复方在体外均可以显著促进淋巴细胞增殖,提高淋巴细胞IFN-γ、IL-10 mRNA的表达;作为佐剂,两个复方可以显著提高免疫兔的血清抗体效价,促进体内淋巴细胞增殖,显著促进圆小囊、肠淋巴结等免疫器官的发育,有较高的攻毒保护效果。【结论】两个复方中药成分具有较强的免疫增强作用,可被开发成新型的免疫增强剂。