Combined effects of dietary mannan‐ and fructo‐oligosaccharide on growth indices,body composition,intestinal bacterial flora and digestive enzymes activity of regal peacock (Aulonocara stuartgranti)

A 56‐d feeding trial was conducted to investigate the effect of dietary mannan‐oligosaccharides (MOS) and fructo‐oligosaccharide (FOS) on growth indices, body composition, intestinal bacterial community and digestive enzymes activity of regal peacock. A total of 240 fish were randomly distributed to 15 experimental units (40‐L aquariums) of 16 fish each. These replicates were randomly assigned to one of five treatments in a 2 × 2 + 1 factorial arrangement. The treatments were control diet (no MOS and FOS), diet A (2 gkg^?1 MOS + 1.5 g kg^?1 FOS), diet B (2 g kg^?1 MOS + 3 g kg^?1 FOS), diet C (4 g kg^?1 MOS + 1.5 g kg^?1 FOS) or diet D (4 g kg^?1 MOS + 3 g kg^?1 FOS). The results showed that feeding diet C increased specific growth rate and protein efficiency ratio and decreased feed conversion ratio compared with control diet. Higher intestinal trypsin activity and increased Lactobacillus counts were observed in fish fed diets B and C. All diets significantly elevated body protein deposition and intestinal amylase activity compared to the control diet. In conclusion, the diet supplemented with 4 g kg^?1 MOS + 1.5 g kg^?1 FOS was advantageous over other MOS + FOS‐supplemented diets, with respect to growth performance and health benefits of regal peacock.     

土壤养分、种植年限和种植方式对巴戟天寡糖含量的影响

目的 分析土壤养分、种植年限、种植方式(林下和非林下)等3个重要因子对巴戟天Morinda officinalis品质核心指标寡糖含量的影响,为我国“四大南药”之一的巴戟天种植提供理论与数据支撑。方法 在广东省德庆县巴戟天道地产区选择18个非林下种植点,采用随机多点采样法采集土样和不同生长年限巴戟天样品,测定土壤养分和巴戟天肉质根寡糖含量,分析土壤养分含量和不同生长年限与巴戟天寡糖含量的关系;分别采集林下和非林下种植的巴戟天样品,通过主成分分析探究林下和非林下种植方式巴戟天的品质差异。结果 土壤pH与巴戟天蔗糖含量呈极显著的负相关关系(P<0.01),与寡糖含量呈显著正相关关系(P<0.05);土壤全磷、速效磷、速效钾与1-蔗果三糖、耐斯糖含量呈显著正相关关系(P<0.05)。3年生巴戟天的蔗糖含量显著高于其他生长年限的巴戟天,4年生巴戟天的1-蔗果三糖含量显著高于2年生巴戟天。林下种植巴戟天的品质优于非林下种植。结论 提高土壤中速效磷与速效钾含量可以提高巴戟天品质,4年生巴戟天的药材品质最佳,林下种植有利于提高巴戟天品质。     

阿魏酰低聚糖的生理功能及其在动物生产中的应用前景

阿魏酰低聚糖(FOs)是由阿魏酸羧基与低聚糖羟基通过酯键联接而成的一种阿魏酰衍生物,其可通过酸、酶以及发酵处理植物细胞壁获得.FOs因具有抗氧化、调节免疫及益生等多种生理功能,在动物生产中有广阔的应用前景.本文对FOs的制备、结构与组成、消化吸收以及生理功能进行综述,旨在为其在动物生产中的研究和开发应用提供理论参考.     

壳寡糖对黄曲霉毒素B1致大鼠肝损的干预效果

黄曲霉毒素B₁(Aflatoxin B₁,AFB₁)分布广、肝毒性强,能够导致肝脏氧化性损伤。本研究通过注射AFB₁建立大鼠急性肝损伤模型,探究具有抗氧化活性的壳寡糖(Chitosan oligosaccharide,COS)对肝损伤的干预效果及方式。实验设置空白组、COS对照组、模型组、COS干预组、阳性对照组,连续灌胃8 d,模型组、COS干预和阳性对照组仅在第6天注射1 mg/kg AFB₁。以大鼠血清肝功能指标、脂质过氧化物含量、抗氧化酶活性以及肝脏组织切片,评价COS对肝损伤的干预效果,并利用RNA测序(RNA-Seq)技术获得差异表达基因(Differentially expressed genes,DEGs)以分析COS干预方式。结果表明：与模型组相比,COS干预组显著降低了血清肝功能指标和脂质过氧化物含量,提高了抗氧化酶活性;肝脏切片观察显示COS有利于改善大鼠肝脏形态;RNA-Seq数据表明,COS干预组和模型组比较共有968个DEGs,富集的基因本体(Gen...     

新型生防农药0.4%低聚糖素防治水稻病害试验报告

通过对比试验,了解新型生防农药0.4%低聚糖素防治水稻病害情况。结果表明:0.4%低聚糖杀菌剂能较好的防治水稻稻瘟病、叶鞘腐败病和水稻纹枯病等细胞壁为甲壳质的真菌性病害。使用量以150～200ml/667m2为宜。     

20%寡聚酸碘对水稻白叶枯病的田间防治效果

以20%噻森铜SC 417倍稀释液为对照药剂,进行了20%寡聚酸碘用于防治水稻白叶枯病(病原Xanthomonas oryzae)的大田药效试验。结果表明,对水稻白叶枯病的防治效果从大到小依次为20%寡聚酸碘1 000倍稀释液、20%噻森铜SC 417倍稀释液、20%寡聚酸碘1 500倍稀释液、20%寡聚酸碘2 000倍稀释液和20%寡聚酸碘3 000倍稀释液,防治效果分别为69.28%、67.99%、64.63%、61.36%和56.45%。对防效进行差异性显著分析表明,在0.05水平,20%寡聚酸碘1 000、1 500、2 000倍稀释液与3 000倍稀释液之间差异显著,20%寡聚酸碘1 000、1 500倍稀释液与对照药20%噻森铜SC 417倍稀释液无显著差异。与喷施对照药剂和清水的小区相比,喷施20%寡聚酸碘稀释液的水稻长势更旺盛。证实20%寡聚酸碘对水稻白叶枯病具有一定的防治效果,并能促进水稻生长,建议田间施用1 000~2 000倍稀释液。     

甘露寡糖对半滑舌鳎（Cynoglossus semilaevis GUnther）稚鱼生长、肠道发育和非特异性免疫水平的影响

通过投喂经甘露寡糖强化的卤虫无节幼体,探索其对半滑舌鳎稚鱼（初始体长为1.4 cm左右）生长性能、肠道发育和非特异性免疫水平的影响。试验设两个处理组（对照组和甘露寡糖组）,分别投喂经裂壶藻或甘露寡糖＋裂壶藻强化的卤虫无节幼体。试验进行34 d,每17 d取样1次。结果显示,17 d时甘露寡糖组体长显著大于对照组（P〈0.05）。两组间的特定生长率和存活率无显著性差异（P〉0.05）。RNA/DNA和protein/DNA的比值在17 d时两组间均无显著性差异（P〉0.05）;34 d时甘露寡糖组的RNA/DNA和protein/DNA比值均大于对照组。甘露寡糖组17 d时淀粉酶比活力和34 d时胰蛋白酶比活力显著高于对照组（P〈0.05）。甘露寡糖组的过氧化物歧化酶、过氧化氢酶、过氧化物酶和溶菌酶活性均显著高于对照组（P〈0.05）。甘露寡糖组的微绒毛长度和皱襞高度显著大于对照组（P〈0.05）;黏膜厚度大于对照组,但无显著性差异（P〉0.05）。试验结果表明,甘露寡糖可以提高半滑舌鳎稚鱼肠道发育和非特异性免疫水平。     

Cloning and Characterization of a Novel Endo-Type Metal-Independent Alginate Lyase from the Marine Bacteria Vibrio sp. Ni1

The applications of alginate lyase are diverse, but efficient commercial enzymes are still unavailable. In this study, a novel alginate lyase with high activity was obtained from the marine bacteria Vibrio sp. Ni1. The ORF of the algB gene has 1824 bp, encoding 607 amino acids. Homology analysis shows that AlgB belongs to the PL7 family. There are two catalytic domains with the typical region of QIH found in AlgB. The purified recombinant enzyme of AlgB shows highest activity at 35 °C, pH 8.0, and 50 mmol/L Tris-HCl without any metal ions. Only K⁺ slightly enhances the activity, while Fe²⁺ and Cu²⁺ strongly inhibit the activity. The AlgB preferred polyM as substrate. The end products of enzymatic mixture are DP2 and DP3, without any metal ion to assist them. This enzyme has good industrial application prospects.     

不同药剂防治水稻病害效果试验

通过对几种药剂的防病效果进行试验研究,结果表明:0.4%低聚糖菌剂150～200 ml/667 m2可有效地防治水稻稻瘟病、叶鞘腐败病和水稻纹枯病等病害。     

The Endo-α(1,3)-Fucoidanase Mef2 Releases Uniquely Branched Oligosaccharides from Saccharina latissima Fucoidans

Fucoidans are complex bioactive sulfated fucosyl-polysaccharides primarily found in brown macroalgae. Endo-fucoidanases catalyze the specific hydrolysis of α-L-fucosyl linkages in fucoidans and can be utilized to tailor-make fucoidan oligosaccharides and elucidate new structural details of fucoidans. In this study, an endo-α(1,3)-fucoidanase encoding gene, Mef2, from the marine bacterium Muricauda eckloniae, was cloned, and the Mef2 protein was functionally characterized. Based on the primary sequence, Mef2 was suggested to belong to the glycosyl hydrolase family 107 (GH107) in the Carbohydrate Active enZyme database (CAZy). The Mef2 fucoidanase showed maximal activity at pH 8 and 35 °C, although it could tolerate temperatures up to 50 °C. Ca²⁺ was shown to increase the melting temperature from 38 to 44 °C and was furthermore required for optimal activity of Mef2. The substrate specificity of Mef2 was investigated, and Fourier transform infrared spectroscopy (FTIR) was used to determine the enzymatic activity (Units per μM enzyme: U_f/μM) of Mef2 on two structurally different fucoidans, showing an activity of 1.2 × 10⁻³ U_f/μM and 3.6 × 10⁻³ U_f/μM on fucoidans from Fucus evanescens and Saccharina latissima, respectively. Interestingly, Mef2 was identified as the first described fucoidanase active on fucoidans from S. latissima. The fucoidan oligosaccharides released by Mef2 consisted of a backbone of α(1,3)-linked fucosyl residues with unique and novel α(1,4)-linked fucosyl branches, not previously identified in fucoidans from S. latissima.