Effects of dietary vitamin K levels on bone quality in broilers.

This study was conducted to evaluate the effects of dietary vitamin K (menadione) on bone quality in cage-raised broilers. Three hundred and sixty male broilers were randomly allotted to one of six treatments, with six replicate pens per treatment and 10 chicks per pen. Broilers were fed one of six diets including a control diet or the control diet plus graded levels of vitamin K (0.5 mg/kg, 2 mg/kg, 8 mg/kg, 32 mg/kg and 128 mg/kg). Water and feed were provided ad libitum during the 7-week experimental period. Results indicated that vitamin K supplementation of broilers diets significantly effected bone quality and feed efficiency. The treatment containing vitamin K at 8 mg/kg improved growth performance (during weeks 6-7) and bone quality (during weeks 0-3). In our study, hydroxyapatite binding capacity of serum osteocalcin (during weeks 0-3), bone breaking strength, bone flexibility, bone ash weight increased linearly (P < 0.05) and bone mineral density, bone mineral content increased quadratically (P < 0.05) with increasing supplementation of vitamin K. In conclusion, to gain optimum bone quality and broiler performance, our studies suggest that the concentration of vitamin K in broilers diets should be 8 mg/kg, 2 mg/kg, and 2 mg/kg, for the starter, grower and finisher phases, respectively. Furthermore, it was shown that the starter period is an important phase for improving bone quality. In addition, this study validated the mechanism of vitamin K effects on bone quality. Vitamin K boosts the carboxylation of osteocalcin and decreases the concentration of serum under-carboxylated osteocalcin enhancing hydroxyapatite binding capacity of serum osteocalcin and improving bone quality.     

播量对水稻生长发育及干物质积累的影响

用盆栽方法进行播量对寒地水稻生长发育及干物质积累影响试验,结果表明:稀播的秧苗发根力强、分蘖多、茎基宽、充实度高。播量200g/m2的产量最高。     

迷宫螺旋槽的选取研究

以提高迷宫螺旋泵的扬程、流量、效率、汽蚀等性能参数为目标,给出不同使用条件下螺旋槽形状与几何参数的选取。     

S1核酸酶突变检测法的优化

优化了S1核酸酶突变检测体系,结果表明(1)扩增法比杂交法产生异源双链DNA更节省时间;(2)PCR产物可以直接作为突变检测的底物;(3)适当降低反应温度、适当增加反应缓冲液中的NaCl浓度、适当缩短反应时间可提高突变检测效果。     

BA—Dot—ELISA检测牛结核血清抗体的研究

利用BA—Dot—ELISA检测72份结核变反阳性牛血清,阳性率为69.5％,比常规ELISA(44.4％)高。用该法检测布鲁氏菌病、粘膜病、传染性鼻气管炎、白血病病牛血清及堪萨斯分枝杆菌、偶发分枝杆菌高免牛血清均无交叉反应,但对50份副结核变反阳性牛血清出现了一定的交叉。该法重复性好,简便快速,结果判定不需特殊仪器。     

Acid-induced autoagglutination found in chicken pathogenic Escherichia coli strain.

Chicken pathogenic Escherichia coli strains were found to autoagglutinate in a static culture of trypticase soy broth (TSB). One strain, designated PDI-386, was further studied for its autoagglutinating property. Acidity in the cultured medium caused by glucose degradation induced the autoagglutination. The bacterial cells grown in a glucose-free L-broth could be aggregated by adding acid, which suggests a potentiality of autoagglutination of the strain grown in the L-broth. The autoagglutinating parent (Agg) formed small colonies with irregular edges like rough colonies on the TS agar, whereas its non-autoagglutinating variant (Nag) formed larger smooth colonies with a perfectly round edge. The Nag colony was easily generated from the Agg colony on the TS agar. The autoagglutinating property was very unstable when the bacteria was passed in the TSB, but rather stable in the L-broth. Under electron microscope, the Agg were found to possess pili of more than 20 microns in length. However, the phenotypic expression of autoagglutination did not correlate with that of mannose-sensitive hemagglutination against guinea pig erythrocytes. Incubation of the Nag in the L-broth at room temperature for more than 10 days provoked the reversion of the autoagglutination. There was no difference between the Agg and the Nag in terms of surface hydrophobicity, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns of membrane proteins and LPS, and plasmid profiles. The virulence of the Agg was higher than that of the Nag. The autoagglutination property is, however, so unstable that the pathogenicity of E. coli isolates from chickens should be carefully evaluated.     

Characterization of phosphate species in urban sewage sludges by high-resolution solid-state 31P NMR

The mineral forms of phosphorus in three urban sewage sludges were characterized using high-resolution solid-state phosphorus-31 nuclear magnetic resonance (NMR) coupled to a sequential extraction. The sludges studied were an anaerobically-digested and heat-treated sludge (Paris-Achères), an activated sludge (Briare) and an anaerobically-digested sludge (Nancy). NMR observations were conducted using both single-pulse and cross-polarization sequences in order to distinguish between ³¹P nuclei far from ¹H nuclei, and ³¹P located within a fraction of a nanometre of ¹H. This approach showed that a complex mixture of P species was present in these sludges. A mixture of hydrogenated octocalcium phosphates and apatites was observed in the three samples. Monetite was present in the anaerobically-digested sludge and brushite in the activated sludge. Dehydrogenated condensed calcium phosphates (compounds with a Ca:P ratio higher than 1.0 such as fluorapatite or tricalcium phosphate) and dehydrogenated pyrophosphates were also probably present in the anaerobically-digested sludge. A poorly-ordered wavellite was observed in the three sludges after the HCl extraction. However, results were inconclusive as to whether this mineral was present in the three sludges, or had been precipitated during the sequential extraction.     

桃需冷量遗传特性的研究

对桃的９个杂交组合４６３株杂种实生苗需冷量进行测定,统计结果表明：桃需冷量是由多基因控制的,Ｆ＿１需冷量平均值较亲中值短,不同组合偏离程度不同,南山甜桃、红日、玛丽维拉、白凤、大久保需冷量育种值分别为１５９、２１６、３１９、８３１、８３４ｈ,遗传传递力分别为７９%、５４%、９２%、８３%、９３%。需冷量的遗传力为８９．６９%。萌芽开花与需冷量密切相关。     

松针叶绿素－胡萝卜素软膏稳定性的研究

松针叶绿素－胡萝卜素软膏中含有β－胡萝卜素、维生素Ｅ、叶绿素等生物活性物质，这些物质的不足之处是稳定性较差．试验结果表明，松针叶绿素－胡萝卜素软膏在室、温避光条件下贮藏１年，不同品种产品中生物活性物质降低幅度是不同的．马尾松针叶叶绿素－胡萝卜素软膏产品中生物活性物质降低幅度分别为（％）：β－胡萝卜素１２．４，维生素Ｅ９．９，叶绿素１０．４；赤松针叶叶绿素－胡萝卜素软膏产品中生物活性物质降低幅度分别为（％）：β－胡萝卜素２５，１，维生素Ｅ．１６．４，叶绿素１２．８；樟子松针叶叶绿素－胡萝卜素软膏产品中生物活性物质降低幅度分别为（％）：β－胡萝卜素１４．８，维生素Ｅ１２．３，叶绿素２４．０．马尾松针叶叶绿素－胡萝卜素软膏产品，在室温避光条件下贮藏１５年，β－胡萝卜素损失４８．１％，维生素Ｅ损失１８．９％，叶绿素损失２９．６％．     

分散松香施胶剂性能影响因素的探讨

对逆转法制备分散松香施胶剂过程中的主要因素如乳化剂的种类及用量、马来松香加合物含量、搅拌转速、加料速度和乳化温度等系统地进行了探讨，提出了合理的工艺条件，并对实际生产中可能出现的问题及解决办法进行了阐述。