Effects of dietary yeast cell wall on faecal bacteria and fermentation products in adult cats

This study evaluated the effects of increasing concentrations of spray‐dried yeast cell wall (YCW) in diets for healthy adult cats on apparent nutrient digestibility and on bacterial composition and fermentation products in the stool. Fourteen cats with an average weight of 4.40 ± 1.05 kg and an average age of 6.2 ± 0.54 years were used and assigned to treatments in an unbalanced randomized block design (by experimental period) with two blocks and three or four cats per diet in each block. Treatments included: control (0% YCW), 0.2% YCW, 0.4% YCW and 0.6% YCW, totalling seven animals per experimental diet. We found that YCW did not affect body weight, nutrient and food intake, faecal production, faecal score, faecal pH or urine output (p > .05). Regarding faecal bacteria, we observed a linear reduction in Clostridium perfringens, a quadratic reduction in Escherichia coli, and linear increases in Bifidobacterium spp. and Lactobacillus spp. (p < .05) with the inclusion of YCW. Regarding the faecal short‐chain fatty acid profile, butyrate, valerate, total biogenic amines, putrescine, cadaverine and histamine increased linearly (p < .05) with the inclusion of YCW. It was concluded that in healthy adult cats, consumption of YCW modulates the faecal bacterial populations, with an increased presence of beneficial bacteria and a reduction in some potentially pathogenic bacteria. It was concluded that YCW modulated the levels of fermentation products. There was an increase in fermentation products coming from carbohydrate metabolism, an important effect that can potentially benefit the intestinal health of cats. The consumption of YCW also increased the fermentation of nitrogen compounds, which have not yet been defined as deleterious or beneficial. The fermentability of carbohydrates and nitrogen compounds may be associated. Therefore, YCW may cause rapid fermentation of both classes of compounds by enhancing the fermentability of one class.     

饲粮添加酵母寡聚糖对高密度养殖条件下蛋鸡生产性能、蛋品质、血清生化指标和肠道健康的影响

本试验旨在研究饲粮中添加酵母寡聚糖(YOS)对高密度养殖条件下蛋鸡生产性能、蛋品质、肠道黏膜形态结构及微生物区系分布、血清生化指标和肠道功能相关基因表达的影响。选取864只12周龄海兰褐蛋鸡,随机分为6个组,每组12个重复,每重复3个笼子,每个笼子3只(低密度)或5只(高密度)。对照组饲喂基础饲粮,试验组饲喂在基础饲粮中分别添加250和500 g/t YOS的饲粮,试验期18周。结果表明:1)饲粮添加YOS能显著提高蛋壳颜色的均匀度(P0.05)。2)饲粮添加YOS增加了蛋鸡肠道绒毛高度/隐窝深度值(P=0.059),其中250 g/t YOS组显著高于对照组(P0.05)。3)饲粮添加YOS使得蛋鸡空肠乳酸杆菌数量显著增加(P0.05),大肠杆菌数量显著减少(P0.05),其中250 g/t YOS组菌群变化较为明显。4)饲粮添加YOS显著降低了蛋鸡血清中内毒素含量(P0.05),提高了免疫球蛋白A含量(P=0.090),且250 g/t YOS组较对照组显著提高(P0.05)。由此可见,饲粮中添加YOS能够改善高密度养殖条件下蛋鸡肠道功能,添加剂量以250 g/t的综合效果较佳。     

离子交换树脂纯化大豆糖蜜上清液

大豆糖蜜上清液中除大豆低聚糖(蔗糖、棉子糖和水苏糖)外,还含有色素、无机盐、含氮组分和有机酸等杂质。本文主要研究了离子交换树脂纯化脱色糖蜜上清液过程中去除杂质的机理并优化了纯化工艺。结果显示:脱色上清液中主要的含氮组分有5种游离氨基酸(天冬氨酸、谷氨酸、天冬酰胺、丙氨酸、酪氨酸)和1种二肽(谷氨酸-酪氨酸)。用离子交换树脂直接处理脱色上清液的效率很低,含氮组分在3倍柱体积处理量时穿透;而离子交换树脂对纯含氮组分的吸附能力很强,处理量约为40倍柱体积。因此,无机盐(Na~+、K~+和Cl~-)和有机酸(柠檬酸)成为了树脂吸附含氮组分的制约因素。用电渗析法脱除无机盐后,阳离子交换树脂对含氮组分的吸附效果显著改善,处理量升高到35倍柱体积;继续用阴离子交换树脂吸附阳离子树脂流出液中的有机酸,即可获得高纯度的大豆低聚糖。同时通过拟合Thomas方程,分别计算了阳离子交换树脂吸附含氮组分和阴离子交换树脂吸附柠檬酸的最大固相吸附浓度。     

母乳低聚糖及其在婴幼儿配方乳粉中的替代品研究进展

母乳低聚糖（human milk oligosaccharides，HMOs）是母乳的重要成分，研究非母乳低聚糖与HMOs之间的差异是实现婴儿配方乳粉母乳化、提升婴儿配方乳粉营养功能、满足婴儿营养健康的基础性工作。本文综述近几年关于HMOs种类、结构特征、HMOs对肠道微生物的调节、肠道健康及免疫系统发育影响的研究成果，同时比较常见动物乳中低聚糖的构成与HMOs的差异，阐述目前婴儿配方乳粉中常用低聚糖的特点及其功能，提出低聚糖在婴幼儿配方乳粉中应用存在的问题与展望，为开发新型婴儿配方乳粉提供理论指导。     

Conditions of Imbedded Immobilization for the Treatment of Methanol Wastewater by Immobilized Microorganism

Methanol-concentrated wastewater is chosen to optimize the conditions of imbedded immobilization of microorganisms through a series of experiments. Activated sludge is imbedded in some little balls with the imbedding materials of Sodium Alginate and PVA, then orthogonal experiments of methanol wastewater treatments are done based on the decomposition of the indicator of COD. Whereafter, the optimum imbedding conditions of Sodium Alginate and PVA are determined and the performance of immobilized ball is improved under those conditions. Meanwhile, the study analyses the performance of the ball based on such parameters as the specific surface area, penetrability and electronic-microscope photo. It is concluded that reaction time is the most important factor, both SA and PVA are reticulations and their structures are suitable to grow for microorganisms, and the mechanical performance of the PVA immobilized ball is improved to a large scale after adding some chemicals.     

不同功能性寡糖组合对锦江黄牛瘤胃固相微生物多样性的影响

研究功能性寡糖组合对锦江黄牛的瘤胃固相微生物多样性的影响。选择3头健康且体重相近的安装有永久性瘤胃瘘管的锦江黄牛,采用自身对照方法,试验分3期进行,第1期:对照期,饲喂基础日粮,不添加任何寡糖;第2期:GT1添加期,饲喂基础日粮+0.8%甘露寡糖+1.0%果寡糖+0.8%大豆寡糖,第3期:GT2添加期,饲喂基础日粮+0.8%甘露寡糖+1.20%果寡糖+1.0%大豆寡糖,每期持续14 d。利用PCR-DGGE方法进行分析牛瘤胃固相微生物PCR-DGGE图谱条带数及相似性。结果发现:添加功能性寡糖组合后,对锦江黄牛瘤胃固相微生物PCR-DGGE图谱条带数影响不明显。3头牛3个试验期DGGE图谱的相似度较高。对锦江黄牛瘤胃液相微生物多样性影响有待下一步研究。     

可食性抗菌膜的研制及其在草莓保鲜中的应用

[目的]研制出可用于草莓的抑茵保鲜的可食性果蔬保鲜抗菌膜.[方法]先用浓度为80％的乙醇溶液分别提取大黄、地榆、丁香和肉桂,然后进行中草药抑茵试验探索其对草莓灰霉菌的抑菌效果;再以膜的力学性能、吸水率、水蒸气透过率以及抑菌性能为依据,分别确定海藻酸钠的浓度、交联剂的种类、交联剂溶液的浓度、交联时间和丁香与海藻酸钠的比例;最后,将可食性抗菌膜处理草莓后,分别测定草莓腐烂率、失重率、呼吸强度和维生素等指标的变化,来探索抗茵膜的保鲜效果.[结果]试验表明,丁香和肉桂具有广普抑菌性,其中丁香的抑菌性最佳,尤其对草莓灰霉菌的抑菌效果最好;海藻酸钠的浓度为2％,交联剂为4％的CaCl2、交联20 min以及丁香与海藻酸钠比例为7:43时抗菌膜具有最佳的物理和抑菌性能;保鲜组草莓烂果率、失重率、呼吸强度和维生素等指标的变化速度均低于空白对照组,保鲜效果较好,草莓在室温下能保存3d,比空白对照组能延长保存2d.[结论]可食性果蔬保鲜膜制作工艺简单、成本低、保鲜效果好、易降解、可食用、对环境无污染,是一种极具开发潜力的果蔬保鲜膜.     

外源寡糖对奶山羊粪便微生物区系的影响

本试验旨在研究不同外源寡糖对奶山羊粪便微生物区系的影响.试验采用不完全拉丁方设计,选用平均体重为(32.80±2.45)kg、安装有永久性瘤胃瘘管的崂山奶山羊6只,分为6组,试验组羊分别饲喂在基础饲粮中添加1％的甘露寡糖(MOS组)、半乳甘露寡糖(GMOS组)、寡木糖(XOS组)、低聚异麦芽糖(IMO组)和果寡糖(FOS组)的试验饲粮,对照组(CT组)羊饲喂基础饲粮.共进行4期试验,每期35 d,其中预试期14d,正试期21 d.于正试期第1、7、14、21天晨饲前采集新鲜粪便,测定粪便中乳酸杆菌、双歧杆菌、大肠杆菌和沙门氏菌的数量.结果表明:与CT组相比,试验组乳酸杆菌数量均有所增加,其中FOS组第7天开始达到极显著水平(P＜0.01);试验组双歧杆菌数量增加,其中FOS组各采样时间均达到极显著水平(P＜0.01);试验组大肠杆菌数量有所降低,其中MOS组和FOS组第7天达到极显著水平(P＜0.01).本试验条件下,不同外源寡糖对增加奶山羊粪便乳酸杆菌、双歧杆菌数量,降低大肠杆菌数量的作用效果不同,其中果寡糖效果较明显.     

甘露寡糖脂质体纳米制剂对鸡生长发育和免疫功能的影响

为研究甘露寡糖脂质体纳米制剂对鸡生长发育及免疫功能的影响,在饲料中添加不同剂量的甘露寡糖脂质体纳米制剂(100、50、25mL g/kg),饲养49d后,测定了鸡体重、料肉比、免疫指标及血液中免疫球蛋白G(IgG)含量。结果表明,甘露寡糖脂质体纳米制剂能提高正常鸡的平均日增重,降低料肉比,其中在1日龄～21日龄阶段,高剂量组和低剂量组平均日增重明显高于药物对照组,差异极显著(P<0.01),与空白对照组比较,差异显著(P<0.05);甘露寡糖脂质体纳米制剂高、中、低剂量组鸡血浆中一氧化氮含量,与药物对照组、空白对照组比较均极显著升高(P<0.01)。说明甘露寡糖脂质体纳米制剂对鸡的免疫功能具有一定的调节作用,发挥抗病促生长作用。     

Alginate as a new biomaterial for the growth of porcine retinal pigment epithelium

Objective Determine the effect of a 3‐dimensional alginate matrix on the growth and differentiation of cells isolated from porcine retinal pigment epithelium (RPE). Procedures Porcine RPE cells were harvested from enucleated eyecups, isolated by differential gravity sedimentation and cultured in either alginate alone (Group 1) or on plastic tissue culture plates followed by alginate (Group 2). Group 1 cells were cultured in alginate to evaluate the efficacy of the matrix as a culture medium. Group 2 cells were initially cultured on plastic to induce dedifferentiation. The cells were then harvested, suspended in alginate beads, and incubated for a second culture period to determine if the induced dedifferentiation was reversible. Results The number of Group 1 cells was significantly greater (P ≤ 0.01) at the end of the culture period. The amount of pigment and cell morphology of Group 1 cells at the end of the culture period was similar to that seen at initial cell isolation. The initial culture of Group 2 cells on plastic showed characteristic features of dedifferentiation marked by the loss of pigment and alterations in microscopic appearance. Secondary culture of dedifferentiated Group 2 cells in alginate beads resulted in a return to pigmentation and characteristic morphology for a majority of the cultured cells. Conclusions Porcine RPE cells can be propagated in alginate culture with a significant increase in cell numbers while maintaining normal morphology. Under the conditions described in the present study, the dedifferentiation of porcine RPE induced by standard in vitro culture methods is reversible.