放牧新疆褐牛年龄胎次对体尺体重的影响

通过在昭苏县测定的1 338头不同年龄新疆褐牛放牧条件下体尺体重等资料进行统计,分析了新疆褐牛年龄、胎次与体尺、体重之间的关系和放牧条件下新疆褐牛生长规律,为有计划的开展育种工作和提高褐牛的终生生产性能提供科学依据.结果表明:新疆褐牛年龄和胎次对体尺、体重有显著的影响.综合分析认为新疆褐牛在相同的饲养管理条件下2岁以前生长发育迅速,是牛生长发育最重要的时期,到2岁时平均体重可达成年(按4岁为成年)牛体重的80;以上,体高、体长等主要体尺指标可达成年牛的90;以上.     

刚体平面复合运动的动力学分析

本文从质点运动微分方程,推出相对运动为绕定轴转动,牵连运动兼有平动和转动的刚体动力学方程,并给出了方程的一般解法。     

水体质量综合评价的物元模型

对水体的可拓性做了充分地分析和研究,说明了利用可拓学方法对水体质量进行分析评价的适宜性.并且应用可拓学的理论和方法,对水体的物征和质量特性进行了全面分析,建立了相应的物元模型,为水体的质量评价提供了一种新的科学方法.     

Out-of-season spawning of cultured pikeperch [Sander lucioperca (L.)]

The aim of this study was to determine the effectiveness of out‐of‐season spawning of cultivated pikeperch (fish that were reared from the larval stage in re‐circulating systems and fed commercial feed exclusively) stimulated hormonally with human chorionic gonadotropin (hCG). The impact of fish age (2+ and 3+) and hormone dosage [200 or 400 IU hCG kg⁻¹ body weight (BW)] on spawning was analysed and expressed as the share of stripped females, commercial fecundity (% BW) and survival of embryos until the eyed‐egg stage (EES index). The possibility of utilizing changes in female pikeperch body weight (CBW index) that are observed following hormone injections as an additional indicator for determining maturity was also investigated. The age and hormone dosage were not noted to have a significant impact on the number of stripped females (≥80% on all groups), the latency period (90–100 h), commercial fecundity (11.3–13.3% BW) or the values of the EES index (61–73%; P>0.05). The mean value of EES from the 3+ age group females was higher than that in the 2+ females, and the interaction between the tested factors (fish age and hormone dosage) wasstatistically significant (P<0.05). In the fish from the control group (injected with a 0.9% NaCl solution), no progress was noted in the maturation of oocytes and no eggs were obtained from any female. It was noted that these females lost BW over the course of the subsequent 24 h of the measurements (P<0.05). In the groups of females that were stimulated hormonally, the opposite phenomenon was observed; in these groups, the CBW index increased significantly between 48 and 96 h following hormone injection. The value of the CBW index was not noted to have been statistically significantly determined by either hormone dose or fish age (P>0.05). The regression equations that described the dependence between CBW and the oocyte maturity stage were highly significant statistically, and the determination coefficient R² assumed a value of 0.76. The most significant increase in BW was related to the oocytes achieving maturity stage III. The BW of pikeperch females with oocytes in this stage was 103% higher than the initial BW. This might be a valuable and useful tool for determining maturity in females of this fish species.     

大肠杆菌BL21(DE3)中表达重组蛋白的研究

为了研究在大肠杆菌BL21 (DE3)中重组蛋白的表达特点,探讨重组蛋白在大肠杆菌中表达时可溶性蛋白与包涵体出现的特点,从表达载体中表达了植物ACC合成酶.经SDS-PAGE电泳与双波长扫描分析,确定目的蛋白随表达时间、菌液密度的增加而增加.但是其最佳表达时间为2.5 h,菌液密度OD600为0.6,IPTG的最佳浓度为0.6 mmol/L,此时目的蛋白含量占全菌蛋白含量之比最高.植物ACC合成酶在大肠杆菌中表达时以包涵体的形式存在,未能检测到可溶性蛋白的表达.     

不同加工方式玉米粉对12月龄伊犁马消化代谢、血浆生化指标及体增重的影响

本试验旨在研究蒸汽压片玉米粉、膨化玉米粉对12月龄伊犁马消化代谢、血浆生化指标及体增重的影响,为蒸汽压片玉米粉、膨化玉米粉在马的饲养实践中的应用提供参考。选取体重相近[(261.95±14.73)kg]、年龄相近(12月龄左右)的伊犁马公马24匹,随机分为3组,每组8匹,分别为对照组、试验Ⅰ组、试验Ⅱ组。各组马匹每天每匹饲喂1.5 kg浓缩料和8 kg苜蓿干草,在此基础上对照组、试验Ⅰ组、试验Ⅱ组马匹每天每匹再分别饲喂1.5 kg的粉粹玉米粉、蒸汽压片玉米粉、膨化玉米粉,进行26 d的消化代谢试验,其中预试期19 d,正试期7 d。结果表明:试验Ⅱ组的干物质、有机物、粗蛋白质、中性洗涤纤维及酸性洗涤纤维的表观消化率分别比对照组高出4.93%(P0.05)、5.84%(P0.05)、7.10%(P0.05)、14.78%(P0.05)、17.45%(P0.05),而试验Ⅰ组的干物质、有机物、粗蛋白质及中性洗涤纤维的表观消化率与对照组相比均差异不显著(P0.05)。试验Ⅱ组的氮沉积量、氮沉积率显著高于对照组及试验Ⅰ组(P0.05),分别高出81.19%、79.86%及104.78%、97.50%,而对照组、试验Ⅰ组间差异不显著(P0.05);试验Ⅱ组的钙、磷沉积量及沉积率均高于对照组、试验Ⅰ组(P0.05)。试验Ⅱ组血浆中葡萄糖含量分别比对照组及试验Ⅰ组高出10.04%、20.79%(P0.05)。饲喂蒸汽压片玉米粉和膨化玉米粉对12月龄伊犁马的体增重和平均日增重无显著影响(P0.05),但试验Ⅱ组试验期内的体增重、平均日增重分别较对照组高出18.88%、20.37%,分别较试验Ⅰ组高出20.43%、20.37%。因此,饲喂膨化玉米粉可提高12月龄伊犁马对饲粮中营养物质的表观消化率及能量代谢,并促进马的生长;而饲喂蒸汽压片玉米粉对12月龄伊犁马的营养物质代谢、血浆生化指标及体增重均无显著影响。     

肉仔鸡休蛋白、胴体蛋白、羽毛蛋白潜在沉积速率模型的建立

本文通过饲养屠宰试验研究了肉仔鸡体组成、体组分的生长发育规律,并建立了肉仔鸡体蛋白、胴体蛋白、羽毛蛋白潜在沉积速率模型,旨在为建立精确的肉仔鸡生长预测模型奠定基础.试验选取180只体重相近的1日龄爱拔益加(AA)肉仔鸡按性别随机分为两个处理,每个处理5个重复,每个重复18只鸡,肉仔鸡饲喂NRC(1994)营养标准水平日粮.于0、7、14、21、28、35、42日龄08:00空腹称重后,每个重复选取接近平均体重的两只鸡进行屠宰试验.采用Gompertz生长模型拟合肉仔鸡体组成及体组分随时间变化的关系,采用曲线回归拟合肉仔鸡体蛋白、胴体蛋白、羽毛蛋白重与体重、胴体重及羽毛重间的异速生长关系,同时结合以上拟合方程推导肉仔鸡体蛋白、胴体蛋白、羽毛蛋白潜在沉积速率模型.结果显示,Gompeertz生长模型能够较好的拟合肉仔鸡体组成及体组分随时间变化的函数关系,拟合回归方程的相关指数(R2)均达到0.969以上,F检验达到显著水平(P＜0.01);曲线回归拟合试验数据得到体组成及体组分间幂函数形式的异速生长方程,其相关指数(R2)均达到0.998以上,F检验达到显著水平(P＜0.01);同时根据以上拟合回归方程建立了肉仔鸡体蛋白、胴体蛋白、羽毛蛋白与肉仔鸡体重、胴体重及羽毛重间的函数关系.以上结果表明,可以通过内仔鸡体重、胴体重及羽毛重对内仔鸡每日体蛋白、胴体蛋白及羽毛蛋白最大沉积量进行预测.     

Effect of Pasteurized Colostrum on Growth Performance and Development of Gastrointestinal Tract of Calves

The effects of pasteurized colostrum on growth performance and development of the gastrointestinal tract of calves were studied in this test. Twenty healthy newborn Holstein calves with similar body weight were randomly divided into two groups. The calves in control group were fed non-pasteurized colostrum while that in experimental group were fed on pasteurized colostrum. The experiment lasted for 90 days. The body weight,average body gain (ADG),average daily feed intake (ADFI),F/G and diarrhea rate were determined and at 0,30,60 and 90 days old,the body indexes were measured. The results showed that compared with control group,the ADFI and ADG of calves at 90 days old in experimental group were increased 1.74% and 2.33% (P> 0.05),and cannon circumference and body length were increased 2.68% and 1.41% (P> 0.05),while the diarrhea rate and F/G were decreased 0.67% and 2.40% (P> 0.05).There was no significant effect of pasteurized colostrum on the complex stomach weight,small intestine weight and small intestine length (P> 0.05). However,the ratio of complex stomach weight to body weight in control group was significantly higher than that of experimental group (P< 0.05). In conlusion,the pasteurized colostrum had a positive impact on growth performance for calves in 90 days old.     

Effects of chronic obesity and weight loss on plasma ghrelin and leptin concentrations in dogs

The objective of this study was to evaluate, in dogs, the effects of obesity and weight loss on plasma total ghrelin and leptin concentrations. Twenty-four Beagle dogs, 12 control lean and 12 obese dogs of both genders and aged between 1 and 9 years, were used for the experiments. Mean body weight was 12.7+/-0.7 kg for the lean group and 21.9+/-0.8 kg for the obese group. The trial was divided into three phases. During phase 1, all 24 Beagle dogs were fed a maintenance diet. During phase 2, the obese dogs were submitted to a weight loss protocol with a high protein-low energy diet. The weight loss protocol ended once dogs reached optimal body weight. During phase 3, the dogs that were submitted to the weight loss protocol were maintained at their optimal body weight for 6 months. Plasma total ghrelin, leptin, insulin and glucose concentrations were measured to evaluate the effects of obesity and weight loss on these parameters in dogs. Body weight, body condition score, thoracic and pelvic perimeters, and ingested food amounts were also recorded during the study. Obese dogs demonstrated a significant decrease in plasma ghrelin and a significant increase in plasma leptin and insulin concentrations when compared with control dogs. During weight loss, significant increases in plasma total ghrelin and glucose and significant decreases in plasma leptin and insulin were observed. The increase in plasma ghrelin concentrations seemed to be transient. Body weight and the morphometric parameters correlated positively with leptin concentrations and negatively with total ghrelin concentrations. These results suggest that ghrelin and leptin could play a role in dogs in the adaptation to a positive or negative energy balance, as observed in humans.     

担子菌发酵产物对肉鸡血糖的影响

本研究选用的药用真菌为担子菌变种,探讨其在山芋渣等(称营养基质,下同)混合配方进行固体发酵(其发酵产物称药用菌质)和在山芋渣等混合物加黄芪(称药性基质,下同)组成的复合配方(称全性基质,下同)进行固体发酵(其发酵产物称药性菌质)。初步进行了菌质对肉鸡血糖和增重效应的研究,结果显示,菌质作为饲料添加剂饲喂AA肉鸡,对AA肉鸡的血糖代谢有明显的调节作用,试验组的血糖浓度显著高于对照组(P<0.05),在20日龄~42日龄中,试验组的动态性血糖浓度变化在25日龄、30日龄有降低趋势,而对照组在20日龄~42日龄中则变化不明显;菌质对AA肉鸡有显著性的增重作用,药用菌质与药性菌质之间差异显著(P<0.05)。