基于SPME-GC-MS和电子鼻的鱼粉挥发性物质分析

为了能够全面、快速分析鱼粉的新鲜度,将电子鼻与顶空固相微萃取气质联用技术结合,以挥发性物质含量辅助评价鱼粉的新鲜度。首先,采用顶空固相微萃取方法对18种储藏时间鱼粉的挥发性物质进行了分析,得到不同储藏时间鱼粉的挥发性物质种类和含量,以及挥发性物质变化规律;采用多元线性回归方法和最近邻回归方法对鱼粉各类挥发性物质和表征新鲜度的标记物与电子鼻传感器响应建立了模型。结果表明:顶空固相微萃取气质联用(Solid phase microextraction-gas chromatography-mass spectrometry,SPME-GC-MS)共鉴定出101种,主要包括醇类化合物、醛类化合物等11类挥发性物质,其中醛酮类化合物种类较多。随着鱼粉逐渐腐败,气味阈值较低的醛类化合物相对含量逐渐降低、酮类化合物相对含量逐渐升高,并出现了二甲基三硫、三甲胺等表征鱼粉新鲜度的标记物;在储藏过程中,醇类化合物相对含量呈先上升后下降趋势;酸类化合物、含氮化合物、含硫化合物相对含量则呈上升趋势。与多元线性回归方法相比,最近邻回归方法具有更好的预测能力,测试集相关系数在0.763 3～0.999 9之间,均方根误差在0.086 7%～8.465 5%之间。     

木材树种对刨花/EPS泡沫复合轻质刨花板性能的影响

为实现刨花板轻量化,通过向芯层引入聚苯乙烯(EPS)泡沫颗粒,制备平均密度为500 kg/m^3的刨花板,探索表芯层刨花构成对板材的剖面密度分布和物理力学性能的影响。结果表明:以杨木细刨花为表层、桉木粗刨花和EPS泡沫颗粒混合物为芯层制备的复合轻质刨花板,其表芯层密度差异最为显著,力学性能达到GB/T 4897-2015《刨花板》中干燥状态下使用的家具型(P2型)刨花板的要求。     

葵瓜子壳氯原酸的提取工艺研究

本试验采用3因素3水平的正交试验方法,以提取物的OD值为测定指标,探讨了葵瓜子壳主要抗菌成分氯原酸的最佳水浸提工艺条件。结果表明,葵瓜子壳主要抗菌成分氯原酸提取物的最大吸收波长为326nm,最佳水浸提工艺条件为料水比1∶10,浸提温度60℃,pH值为6。     

Effect of enzymes of microbial origin on in vitro digestibilities of dry matter and crude protein in soybean meal

The effects of supplementation with cellulase, xylanase, pectinase, hemicellulase, glucanase, phytase and protease of microbial origin on digestibility of crude protein (CP) and dry matter (DM) of soybean meal in vitro were examined in the present study. Changes in viscosity during in vitro digestion were also examined as an index of carbohydrate digestibility. Hemicellulase and all enzyme combinations without protease showed significant improvement of CP digestibility. Cellulase, xylanase, phytase and glucanase tended to improve CP digestibility. Dry matter digestibility was improved significantly by pectinase and all enzyme combinations. Cellulase and phytase tended to improve DM digestibility. Crude protein and DM digestibilities were the highest when all the enzymes except protease were added. Protease, cellulase, pectinase, xylanase, glucanase and hemicellulase significantly reduced viscosity, while phytase had no effect on viscosity. Viscosity was increased unexpectedly when all the enzymes were added. These results strongly suggest that a combination of carbohydrases improves the CP and DM digestibility of soybean meal while protease inhibits the actions of these enzymes. The present study also suggests that viscosity is not always a good index of digestibility. Moreover, excluding the protease from commercial crude enzyme preparations may improve digestibility.     

Mononuclear phagocyte receptors in rhesus monkeys (Macaca mulatta) and their role in hemolytic disease of the newborn

Hemolytic disease of the newborn does not develop in rhesus monkeys because placentally-transferred maternal antibodies do not induce immune clearance of the newborn's erythrocytes. In an in vitro RBC adherence assay, rhesus peripheral blood monocytes did not bind newborn's RBC which had been coated in utero or in vitro with maternal antibodies. Nevertheless, rhesus phagocytes possess receptors that are specific for the Fc portion of IgC and for the C3b. Using purified human IgG subclasses as inhibitors of RBC adherence, rhesus Fc receptors preferentially bind IgG1 and IgG3. Thus, it may be that maternal antibodies are non-opsonic because they belong to IgG subclasses that do not bind effectively to rhesus Fc receptors. Also, RBC adherence appears to be controlled by the level of antibody coating which in turn is determined by avidity of the antibodies and by the number of RBC membrane determinants. The failure of maternal antibodies to opsonize the newborn's RBC and thus cause hemolytic disease is very likely due to the low avidity of antibodies and to the weak expression of blood group determinants on the membranes of these RBC.     

用复合蛋白素替代豆饼饲喂黄牛的效果研究

用复合蛋白素替代精料中 1 0 0 %的豆饼 (试验Ⅰ组 )和 50 %的豆饼 (试验Ⅱ组 )饲喂黄牛。结果表明 :精料成本分别降低了 1 3 .45 %和 6 .76 % ;试验I组平均日增重比对照组提高了 62g(P <0 .0 5) ,试验Ⅱ组平均日增重未得到显著提高 (P >0 .0 5) ;试验Ⅰ组和试验Ⅱ组经济效益 (日均粗收益 )分别比对照组提高 76 .1 9%和 40 .2 9%。     

脱毒菜籽饼对鸡饲养效果的评价——Ⅱ.代谢能与氨基酸消化率的测定

在京黄肉鸡和京白蛋鸡上应用 Sibbald“鸡真代谢能”快速测定法,测定了脱毒菜籽饼,菜籽饼、豆饼和鱼粉的表观代谢能含量和氨基酸的消化率。试验结果表明:(1)酸法脱毒工艺生产的脱毒菜籽饼与原菜籽饼的表观代谢能含量相近,分别为8.91和9.41MJ/kg(蛋鸡);(2)在13种饲料氨基酸中,脱毒菜籽饼和菜籽饼低于鱼粉和豆饼,各占21.65%,20.41%;(3)脱毒菜籽饼在蛋鸡体内氨基酸的平均消化率为87.73%,比鱼粉或豆饼中氨基酸的平均消化率仅低4.25%或2.36%,但比原菜籽饼高15.32%,说明脱毒工艺提高了菜籽饼中氨基酸的消化率。试验证明,用脱毒菜籽饼代替鸡饲粮中的豆饼是可行的。同时,还测得肉鸡对饲料中能量的利用和氨基酸的消化率高于蛋鸡,用四种蛋白质饲料饲喂京黄肉鸡的 AME 值平均比京白蛋鸡高3.74%,氨基酸的消化率京黄肉鸡比京白蛋鸡高5.79%。     

青钱柳醇提取物对糖尿病小鼠降血糖作用的研究

采用四氧嘧啶选择性破坏昆明种小鼠的胰岛β细胞,造成实验性糖尿病模型小鼠共160只,随机分成5组,每组2个重复,设消渴丸组、四氧嘧啶组,青钱柳提取物高、中、低浓度组。尔后用青钱柳醇提取物给该小鼠灌胃,测定其空腹血糖浓度,观察小鼠血糖浓度和体重变化,最后进行糖耐量试验。结果表明:在灌胃青钱柳70%醇提取物2周和3周后,高、中浓度的青钱柳醇提取物组小鼠的血糖浓度明显低于糖尿病模型组小鼠的血糖(P<0 05);给药4周后,高、中浓度组和消渴丸组小鼠的血糖浓度明显低于糖尿病模型组的血糖浓度(P<0 05);给药5周和6周后,低浓度组和消渴丸组小鼠的血糖浓度明显低于糖尿病模型组的血糖浓度(P<0 05),而高、中浓度组小鼠的血糖浓度与糖尿病模型组的血糖浓度相比,差异极显著(P<0 01);在第4周和第5周时,低浓度组小鼠的体重明显低于空白对照组小鼠的体重(P<0 05);同时,青钱柳对试验性小鼠的糖耐量具有显著的增强作用。     

双低菜籽饼作雏鸡日粮营养价值研究

研究结果表明，日粮双低菜籽饼比例为１０％、１５％时，与全豆饼日粮比较，雏鸡生长发育、饲料增重比差异不显著。甲状腺无明显肿大，血清Ｔ３、Ｔ４、ＴＳＨ、ＴＧ、Ｔｍ未见异常。