Effect of phenolic nonprotein amino acid L-dopa (L-3,4-dihydroxyphenylalanine) on growth performance, metabolic rates and feed nutrient utilization of common carp (Cyprinus carpio L.)

Two experiments (I and II) were conducted to evaluate the effect of nonprotein phenolic amino acid, L ‐dopa (L ‐3,4‐dihydroxyphenylalanine) on growth, metabolism and feed assimilation of common carp. Six isonitrogenous and isoenergetic diets (diets 1–6 containing 0, 2.5, 7.0, 14, 28 and 56 g kg^–1L ‐dopa, respectively) were prepared by replacing wheat meal in the feed with L ‐dopa. For experiment I (8‐week duration), each treatment had two replicates with five fish each per replicate (mean initial body mass of 13.4 ± 1.0 g), whereas five groups of carp, each consisting of three fish, individually kept in respiration chambers, giving three replicates per treatment with a mean body mass of 25.0 ± 1.8 g were used for experiment II (4‐week duration). Fish were fed six times their maintenance ration daily (3.2 g feed kg^–0.8 day^–1). No fish died during either experiment. In experiment I, the growth rate, feed conversion ratio (FCR), protein efficiency ratio (PER) and apparent net protein utilization (ANPU) of carp fed diets 1, 2 and 3 were similar but they were significantly (P < 0.05) higher than those in dietary groups 4, 5 and 6. However, no significant differences were observed with regard to body composition (moisture, protein, lipid, ash and energy contents) between control (1) and the diets 2, 3, 4 and 5. Fish fed diet 6 had reduced lipid and energy contents (P < 0.05) when compared with other dietary groups. In experiment II, L ‐dopa significantly increased the oxygen consumption per unit body weight gain in treatments 4, 5 and 6. The average metabolic rate also tended to be higher in these groups. The energy expenditure was similar in treatment groups, but the energy retention was significantly lower and energy dissipated significantly higher in dietary groups 4, 5 and 6. The cholesterol level in blood plasma between the control and L ‐dopa containing diets was not significantly different. It may be concluded that at higher inclusion rates (>7 g kg^–1) L ‐dopa appears to be a major antinutrient and hence the protein sources of plant origin, containing high amounts of L ‐dopa (i.e. mucuna beans) should be used with caution as fish meal substitutes in carp diets.     

Aspergillus carneus M34聚木糖酶与植酸酶同步生产的评估及聚木糖酶最适化生产

半纤维素为自然界中仅次于纤维素的木质纤维素,而聚木糖为农业废弃物中最主要的半纤维素成分,与聚木糖降解有关的酵素总称为聚木糖酶群(xylanolyticenzymes)(Collinsetal.,2005)。植酸(phyticacid)广泛存在于自然界中,植物中的含磷化合物多以此形式存在(Cosgrove,1966),植酸酶(phytase)能将植酸分解成肌醇、肌醇磷酸及无机磷。利用培养条件探讨了同步提升聚木糖酶(xylanase)与植酸酶(phytase)活性的可行性,并以茭白笋壳中获得的半纤维素为碳源,利用反应曲面法进行聚木糖酶的最适化生产。以期了解AspergilluscarneusM34之聚木糖酶与植酸酶2种酵素的生产关系,并对农业废弃物的再利用有所贡献。依据磷源、碳源与实验设计之结果,显示聚木糖酶及植酸酶,在因子种类的选择以及阶层的调整时,无法由同一个因子的改变而达到活性同步提升之目的。中心混成实验所得到的数学模式,平稳点的形式为鞍点,预估的聚木糖酶活性为11.66U/mL;而在聚木糖酶最适化生产上,当碳源为1.5%茭白笋壳半纤维素,氮源为0.8%酵母萃取物与0.4%氯化铵,起始pH值为7.00,于30℃培养5d后,可获得的最大酵素活性为(27.31±1.14)U/mL。     

A leaf rust resistance gene, different from Lr34, associated with leaf tip necrosis in wheat

The gene Lr34 has contributed to durable resistance to leaf rust caused by Puccinia triticina in wheat worldwide. The closely associated leaf tip necrosis is generally used as the gene's marker. Lr34 has been postulated in many Indian bread wheat cultivars including ‘C 306’, based on the associated leaf tip necrosis and a few other field and glasshouse observations. The present study showed monogenic control of adult‐plant resistance in ‘C 306’ to leaf rust pathotype 77‐5 (121R63‐1). The F₂ segregation in the crosses between ‘C 306’ and the two known carriers of Lr34, ‘Line 897’ and ‘Jupateco 73’‘R’ fitted a digenic ratio. The F₃ families derived from the susceptible F₂ segregants were true breeding for susceptibility, proving the absence of Lr34 in ‘C 306’. The cross between ‘Line 897’ and ‘Jupateco 73’‘R’ did not segregate for susceptibility. Resistance in the cross ‘Agra Local’ (susceptible) × ‘C 306’ was associated with leaf tip necrosis, showing that the leaf rust resistance gene in ‘C 306’ was associated with leaf tip necrosis, but was different from Lr34. This gene is being temporarily designated as Lr‘C 306’. Hence, leaf tip necrosis cannot be considered as an exclusive marker for selecting Lr34 in wheat improvement.     

吖啶橙免疫荧光菌团培养浓集法快速检出鸡白痢和禽伤寒沙门氏菌的研究

本文报告经作者实验研究提出的吖啶橙免疫荧光菌团培养浓集法(AOIFBC法)用于人工感染雏肠内容物中S.P和S.g检出的结果:从109例感染雏中分离S.p.,并与常规分离培养对照。本法阳性率31.2％,漏检率3.7％;常规法阳性率17.4％,漏检率17.4％,二者阳性率差异显著(P<0.05),漏检率差异非常显著(P<0.01)离心沉淀物荧光菌团检查与沉淀物分离培养验证结果比较,二者符合率85.3％。从92例感染雏中分离S.g.,与常规分离培养对照。本法阳性率26.1％,漏检率2.2％;常规法阳性率19.6％,漏检率8.7％,二者阳性率和漏检率差异不显著(P>0.05)。离心沉淀物荧光菌团检查与沉淀物分离验证结果比较,二者符合率90.2％。     

四川冕宁县缺硒饲粮对雏鸡的影响及不同品种雏鸡适宜补硒量的研究

采用四川严重缺只硒地区冕宁县实用雏鸡饲粮饲喂泸宁鸡(当地地方鸡)、白洛克和来杭三个品种共682只雏鸡,作了两个试验,结果表明:谷实类缺硒饲粮(含硒0.0051ppm)引起雏鸡严重营养性胰腺萎缩和纤维化;泸宁鸡和白洛克缺硒死亡率分别为83％和63％,添加维生素E可起到轻微缓解作用(缺硒死亡率52％);补硒显著促进生长和改善饲料利用率。饲粮中添加动物性饲料(使基础日粮含硒0.1018ppm)后雏鸡未出现明显缺硒病变,但补硒显著提高谷胱甘肽过氧化物酶(GSH-px活力、组织硒含量和生长速度。雏鸡对缺硒的敏感程度、组织硒含量和GSH-px活力存在明显品种差异。以GSH-px活力和组织硒含量作为评定标准结合对生长速度的考察表明:对于生长较快的泸宁鸡和白洛克,基础饲粮补加0.20ppm硒是适宜的,而对于蛋用型来杭鸡则以添加0.10ppm效果较好。     

GS豫麦21号选育技术及高产稳产性分析

ＧＳ豫麦２１号在１９８３－１９９３年黄淮流域三年区试和河南省两年生产试验中产量均居首位。地区、省、国家三级６年８５点次试验，平均亩产４１６．２ｋｇ，比４个对照种平均增产１１．６７％。其中，１９９２年黄淮流域１１处试验，平均亩产５０６．９ｋｇ。     

强筋优质超高产小麦新品种豫麦68号的选育

豫麦 68号是通过多亲本复合杂交 ,经Co60 辐射选育而成的集强筋优质、高产、抗病于一体的小麦新品种。该品种产量三要素协调 ,具 90 0 0kg/hm2 潜力 ,品质达强筋小麦国家标准 ,高抗主要病害。 2 0 0 0年通过河南省农作物品种审定委员会审定。     

硒和蛋氨酸对雏鸡营养性胰腺萎缩及某些生化指标的影响

用京白Ⅲ系雏鸡进行2×2因子试验(添加蛋氮酸O,0.3％,硒O,0.2PPM),研究了饲粮硒和蛋氨酸缺乏与适量对雏鸡胰腺萎缩(NPA)及胰谷胱甘肽过氧化物酶(GSH-Px)和谷胱甘肽(GSH)的影响。结果表明,雏鸡耗硒一周后出现胰腺变性。缺硒使雏鸡胰、肝脏GSH-Px活性、GSH含量显著降低(P<0.05),GSH/GSSG比例降低。缺硒时1—4周血浆及四周的胰GSH-Px活性、胰硒含量在缺蛋氨酸组显著高于加蛋氨酸组。四周时胰脏GSH含量、GSH/GSSG比例显著低于加蛋氨酸组(P<0.01)。缺硒饲粮中添加蛋氨酸可使缺硒引起的NPA病变程度减轻。     

木粉增强P34HB生物复合材料的制备及其结构性能表征

【目的】通过木粉纤维增强生物塑料聚3-羟基丁酸酯-co-4-羟基丁酸酯(P34HB),为生物复合材料的理论研究和生物可降解塑料的广泛应用提供科学依据和理论支持。【方法】以毛白杨木粉和P34HB为原料,采用共混热压法制备P34HB/木粉生物复合材料,基于电子扫描显微镜(SEM)、差示扫描量热法(DSC)、热重分析(TGA)、傅里叶红外光谱(FTIR)、动态热机械分析(DMA)和力学性能分析等手段对其结构和性能进行表征。【结果】随着木粉含量增加,生物复合材料的拉伸强度、断裂伸长率和弯曲强度先增加后减小,冲击强度逐渐下降,拉伸强度、弹性模量和杨氏模量分别增加89%、59%和103%,储能模量E′逐渐增加,tanδ峰值先下降后上升。生物复合材料的高频率模量大于低频率模量,动刚度比静刚度好。相比P34HB,生物复合材料的热分解区间变宽,热解速率变慢,热解剩余质量增加。【结论】随着木粉含量增加,P34HB分子链运动受阻,生物复合材料的储能模量和脆性增大;同时,木粉纤维的成核作用诱导P34HB形成结晶度高、层状结构发达的横晶层,木粉与P34HB之间界面结合力增强,力学性能和热稳定性明显提高。综合考虑,P34HB/木粉生物复合材料的最佳木粉加入量为50%。