Effects of different dl‐selenomethionine and sodium selenite levels on growth performance,immune functions and serum thyroid hormones concentrations in broilers

This trial was conducted in a 2 × 3 + 1 factorial arrangement based on a completely randomized design to evaluate the effects of different dl ‐selenomethionine (dl ‐Se‐Met) and sodium selenite (SS) levels on growth performance, immune functions and serum thyroid hormones concentrations in broilers. A total of 840 Ross 308 broilers (7 days old) were allocated by body weight to seven treatments (three replicates of 40 birds each treatment) including (1) basal diet (containing 0.04 mg of selenium (Se)/kg; control) without supplementary Se; (2, 3 and 4) basal diet + 0.05, 0.15 or 0.25 mg/kg Se as SS; (5, 6 and 7) basal diet + 0.05, 0.15 or 0.25 mg/kg Se as dl ‐Se‐Met. The experiment lasted 42 days. The results revealed that dietary Se supplementation improved (p < 0.05) average daily gain, feed efficiency, immune organ index, serum immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM) and triiodothyronine (T₃) concentrations and decreased (p < 0.01) thyroxine (T₄)/T₃ ratio in serum compared with the control. Broilers receiving the dl ‐Se‐Met‐supplemented diets had higher (p < 0.05) feed efficiency, thymus index, the amounts of IgA, IgG, IgM and T₃ as well as lower (p < 0.05) serum T₄ concentrations and T₄/T₃ ratio than those consuming the SS‐supplemented diets. Serum IgA and IgM levels of broilers fed 0.15 mg Se/kg were significantly higher (p < 0.05) than those of broilers fed 0.05 or 0.25 mg Se/kg. In summary, we concluded that dl ‐Se‐Met is more effective than SS in increasing immunity and promoting conversion of T₄ to T₃, thus providing an effective way to improve the growth performance of broilers. Besides, based on a consideration of all experiment indices, 0.15 mg Se/kg was suggested to be the optimal level of Se supplementation under the conditions of this study.     

Effect of dietary probiotic,prebiotic and synbiotic supplementation on performance,immune responses,intestinal morphology and bacterial populations in broilers

This study was conducted to investigate the effects of probiotic (Primalac), prebiotic (TechnoMos) and synbiotic (Primalac + TechnoMos) supplementation on performance, immune responses, intestinal morphology and bacterial populations of ileum in broilers. A total of 240 one‐day‐old broiler chicks were randomly divided into four treatment groups which included 60 birds. Control group did not receive any treatment. The chicks in the second, third and fourth groups were fed probiotic (0.9 g/kg), prebiotic (0.9 g/kg) and probiotic (0.9 g/kg) plus probiotic (0.9 g/kg; synbiotic), respectively, at entire period. Daily feed intake, daily weight gain and feed conversion ratio were evaluated. The birds were immunized by sheep red blood cell (SRBC) on days 12 and 29 of age and serum antibody titres were measured on days 28, 35 and 42. Newcastle vaccines administered on days 9, 18 and 27 to chicks and blood samples were collected on day 42. Intestinal morphometric assessment and enumeration of intestinal bacterial populations were performed on day 42. The results indicated that consumption of probiotic, prebiotic and synbiotic had no significant effect on daily feed intake, daily body weight gain, feed conversion ratio, carcass traits, intestinal morphology and bacterial populations of ileum (p > 0.05). Consumption of prebiotic increased total and IgM anti‐SRBC titres on days 28 and 42 and antibody titre against Newcastle virus disease on day 42 (p < 0.05). Synbiotic increased only total anti‐SRBC on day 28 (p < 0.05). It is concluded that consumption of prebiotic increased humoral immunity in broilers. Therefore, supplementation of diet with prebiotic for improvement of humoral immune responses is superior to synbiotic supplementation.     

Dietary mannitol increased the absorption of calcium and magnesium in rats

The effect of mannitol on bone‐related mineral absorption and retention and the mechanism was investigated in this study. Fourteen 8‐week‐old male Wistar rats in experiment 1 and same number and age cecectomized Wistar male rats in experiment 2 were divided into two subgroups of seven animals, respectively, fed diets containing 0 or 4% mannitol for 28 days. Mineral balance tests were determined twice during days 8–12 and days 22–26, and the rats were slaughtered on day 28 both in experiment 1 and experiment 2. The whole caecum and colon were collected with the content to analyse tissue weight, content weight, content's pH and moisture, organic acids' concentration and mineral levels. In experiment 1, Ca absorption and retention and Mg absorption were significantly increased by mannitol feeding during days 8–12. Caecal total weight, tissue weight and content weight were increased, the pH of caecum and colon was reduced, and the concentrations of caecal short‐chain fatty acids (SCFAs) were modified by mannitol feeding. In experiment 2, during days 8–12 and days 22–26, Ca absorption and retention were significantly lowered by mannitol feeding in cecectomized rats; however, mannitol feeding decreased Mg absorption during days 8–12, but did not impact Mg retention. Colonic total weight, tissue weight and content weight were significantly increased, and colonic pH was reduced by mannitol feeding. In conclusion, dietary mannitol increased the absorption of Ca and Mg and the caecum markedly contributed to this promoting effect of mannitol.     

丹参药渣栽培糙皮侧耳和毛头鬼伞

采用不同比例丹参(Salviae miltiorrhiza)药渣替代玉米芯对糙皮侧耳(Pleurotus ostreatus)、毛头鬼伞(Coprinus comatus)供试菌株进行栽培实验.经栽培收获两茬子实体,分别对不同配方两个菌种的菌丝长速、单位料重产量、生物学效率等指标进行统计分析.结果表明:在单位料重产量及生物学效率表现上,随培养料中所含丹参药渣比例增加而增加;在菌丝长速表现上则相反.经丹参药渣、玉米芯的碳氮比分析(28.5∶1;88.1∶1)得知,栽培料中随药渣含量的增加氮素含量相应提高(碳氮比55.27∶1～27.44∶1,氮含量为0.76％～2.43％),成为两个菌种产量增加的主要原因.     

一类二维加权积分数值求积方法及其误差分析

针对一类二维加权积分的数值计算方法及误差分析进行研究,参照一维广义高斯积分数值求积方法提出一种具有较高代数精度的计算方法并对其误差做分析,同时给出几个简明的结果。这些结果可用到诸如小波分解,图像处理与多分辨数字信号处理等领域。     

网络"恶搞"电影作品的法律问题研究

对电影作品的网络"恶搞"是我国网络产业发展的新产物,在形式和内容上都有其显著特点。网络"恶搞"能够迅速流行有深刻的文化和技术背景。从性质上说,网络"恶搞"属于新型文艺评论,也具备构成改编作品的条件。网络"恶搞"在网络的传播可能对电影作品的著作权、相关主体的名誉权和肖像权构成侵犯,尽管如此,我们应当在保护公民言论自由的基础上寻求对其进行规制。     

上海松江中心城区道路绿化类型及景观分析

将松江中心城区道路绿化的配置形式归纳为14个类型,并对各类型的绿化景观效果进行了分析。     

一个水稻三倍体×二倍体杂交F2群体的微卫星杂合性丧失

DB102为一田间发现的三倍体水稻,利用它做母本与二倍体水稻中作59杂交,得到一个早世代(F2)稳定群体,通过微卫星分析发现,该群体中有一些微卫星位点发生了杂合性丧失,且至少6条染色体上发生微卫星位点杂合性丧失(loss of heterzygoisity LOH)可能有DNA序列变化。而微卫星位点的杂合性丧失又可能与该杂交组合早世代稳定有关。     

对北京市新型农村合作医疗制度的调查与思考

自2002年7月北京市大兴区率先在全国开展新型合作医疗试点至今,北京市新型农村合作医疗制度运行已经5年了.在对北京市新型农村合作医疗制度运行情况进行充分调研的基础上,总结了所取得的成效,分析了存在的问题,要进一步完善这项制度应提高筹资水平,实行动态缴费;提高补偿水平,提升制度吸引力;充实管办资源,重视调研能力建设等.     

SrNi2Fe16O27铁氧体的合成与性能研究

采用柠檬酸法合成出超微W型铁氧体。用XRD、VSM测试其结构和磁性能。试验结果表明,该法在1000℃制得的铁氧体性能优于其他方法制得的铁氧体,控制pH值、水量和柠檬酸的量对铁氧体的结构和磁性能都有一定的影响。