不同净能水平日粮对育肥猪生长性能、背膘厚度及眼肌面积的影响

试验研究不同净能水平日粮对育肥猪生长、背膘及眼肌面积的影响.选择420头(38.5±0.5) kg丹系三元育肥猪,随机分为5组,每组6个重复,每个重复14头猪,公、母各半.试验A、B、C、D、E组饲粮净能水平分别为9.84、10.05、10.26、10.46和10.67MJ/kg,预试期7d,正式试验期97 d.结果 ...     

妊娠母猪膘情对繁殖性能的影响

为研究妊娠母猪膘情与繁殖性能的关系,试验随机选用32头妊娠母猪,用B超活体测定其产前3 d倒数3、4肋骨间、胸腰椎结合处、腰荐椎结合处偏离背中线5~8 cm处背膘厚,并与其窝产仔数、产活仔数、死胎数、、仔猪初生重、初生窝重、18日龄断奶重、断奶窝重及断奶后发情天数等指标进行比较。结果显示,背膘厚度较薄组各项繁殖指标普遍优于背膘厚组,说明保持适当膘情对妊娠母猪繁殖性能的提高具有促进作用。     

不同日粮组成对蛋鸡生产性能及鸡蛋品质的影响

选用５７６只１５４日龄海赛克斯蛋鸡探讨不同日粮组成对蛋鸡生产性能及鸡蛋品质的影响。共计３个处理，每个处理４个重复，每个重复４８只鸡，全阶梯三层笼养，自由采食、饮水，进行产蛋率大于８０％的饲养试验。试验期为４周。试验结束后，对各处理的产蛋率、只日产蛋量、料蛋比、破蛋率、每千克蛋耗料成本及蛋的品质指标进行统计分析。试验结果表明，采食３种日粮的试鸡在产蛋量、破蛋率、采食量等指标差异不显著（Ｐ＞０．０５），但采食无鱼粉日粮的试鸡料蛋比、死淘率最低，每千克蛋饲料成本最低（Ｐ＜０．０５），且产蛋率最高（Ｐ＜０．０５）。蛋形指数、蛋壳厚度、蛋壳强度、哈氏单位４项指标上３个处理间无明显差异（Ｐ＞０．０５）。     

低粗蛋白质补充氨基酸日粮对妊娠母猪繁殖性能和蛋白质代谢的影响

选择胎次、预产期、体重相近的妊娠母猪24头,采用单因子试验设计,随机分为3个处理,每个处理设8个重复。对照组饲喂常规饲料,粗蛋白质（CP）水平为14.5%,试验组Ⅰ和Ⅱ为低CP补充氨基酸日粮,其CP水平分别为12.5%和10.5%。各处理氨基酸水平相同。试验期为从配种后20 d左右确定受孕后开始,直到产仔结束。试验结果表明：①与对照组相比,妊娠母猪采食低CP日粮,对其繁殖性能如总产仔数、活仔数、初生重及背膘厚无显著影响（P>0.05）。②对照组血清尿素氮的含量与试验组Ⅰ差异不显著（P>0.05）,而显著高于试验组Ⅱ（P<0.05）。试验组Ⅰ的血清尿素氮的含量与试验组Ⅱ差异显著（P<0.05）。血糖含量随CP水平的降低有下降的趋势,对照组血糖含量与试验组Ⅰ差异不显著（P>0.05）,而与试验组Ⅱ差异显著（P<0.05）;试验组Ⅰ和Ⅱ血糖含量差异不显著（P>0.05）。③饲料CP的表观消化率随着CP的降低有上升的趋势,试验组Ⅰ与对照组相比差异不显著（P>0.05）,而试验组Ⅱ显著高于试验组Ⅰ和对照组（P<0.05）。综上所述,妊娠母猪采食低CP补充氨基酸日粮,对其繁殖性能及背膘厚无显著影响。     

Porosity and capillarity of weft knitted spacer structures

A geometrical model of weft knitted spacer structures made with mono-filament yarn has been analysed to understand the spacer yarn path. Theoretical models have been created to predict the porosity and the radius of the capillaries of a knitted spacer structure depending on their geometrical parameters, such as course spacing, wale spacing, stitch length, fabric thickness, count of yarn and fibre density. Polyester knitted spacer fabrics were produced with different parameters; their porosity was determined by measuring the weight and compared with the theoretical porosity. The validity of the model was confirmed by experimental results. The porosity of knitted spacer structures made out of mono-filament yarn can be maintained above a certain level by adjusting the fabric parameters such as fabric thickness, course spacing and wale spacing.     

Influence of salinity and moisture on the threshold shear velocity of saline sand in the Qarhan Desert,Qaidam Basin of China: A wind tunnel experiment

Determination of the threshold shear velocity is essential for predicting sand transport, dust release and desertification. In this study, a wind tunnel experiment was conducted to evaluate the influence of salinity and moisture on the threshold shear velocity of saline sand. Saline sand samples (mean particle size of 164.50-186.08 μm and the total silt, clay and salt content of 0.80%-8.25%) were collected from three saline sand dunes (one barchan dune and two linear dunes) in the Qarhan Desert, Qaidam Basin of China. Original saline sand samples were placed in two experimental trays for wet and dry processing to simulate deliquescence and desiccation, respectively. Surface moisture content ranging from 0.30% to 1.90% was generated by the steam method so that the saline sand can absorb water in a saturated water vapor environment. The motion of sand particles was determined by the observers with a solid laser. The laser sheet (0.80 cm thick), which was emitted by the solid laser, horizontally covered the sand surface and was bound to the sand. Results show that the cohesion of saline sand results from a combination of salt and water. The threshold shear velocity increases exponentially with the increase in crust thickness for the linear sand dunes. There is a positive linear correlation between the original moisture content and relative threshold shear velocity. The threshold shear velocity of dewatered sand is greater than that of wet sand with the same original moisture content. Our results will provide valuable information about the sand transport of highly saline soil in the desert.     

Reference Values and Repeatability of Transabdominal Ultrasonographic Gastrointestinal Tract Thickness and Motility in Healthy Donkeys (Equus asinus)

The present study aimed to provide reference ranges for the wall thickness and motility pattern of the gastrointestinal tract from a sample of donkeys (Equus asinus) population using B-mode ultrasonography. In the present study, 30 clinically healthy donkeys (Equus asinus) (15 males and 15 females), aged 2–20 year old and weighed 100–280 kg were randomly selected for B-mode ultrasonographic scanning of the abdomen. The wall thickness of the stomach, duodenum, jejunum, left colon, right colon, and cecum was assessed. Moreover, the motility pattern of the duodenum, jejunum, left colon, right colon, and cecum was evaluated over a period of 3 minutes. Abdominal ultrasonographic scanning of the gastrointestinal tract of healthy donkeys explored that the stomach, duodenum, jejunum, left colon, right colon, and cecum could be visualized easily. The wall thickness of the stomach, duodenum, jejunum, left colon, right colon, and cecum was 7.0 ± 0.9 mm, 3.3 ± 1.0 mm, 5.4 ± 0.6 mm, 5.1 ± 0.5 mm, 5.4 ± 0.5 mm, and 5.4 ± 0.6 mm, respectively. The thickest part of the gastrointestinal tract is the stomach, whereas the thinnest part is the duodenum. The motility pattern of the duodenum, jejunum, left colon, right colon, and cecum was 7.7 ± 1.3 contractions/3 minutes, 6.9 ± 1.1 contractions/3 minutes, 4.1 ± 1.2 contractions/3 minutes, 5.5 ± 1.3 contractions/3 minutes, and 4.0 ± 0.8 contractions/3 minutes, respectively. Both the duodenum and jejunum contractions were significantly higher than that of the left colon, right colon, and cecum. This is the first study reporting the reference values for both the wall thickness and motility pattern of the gastrointestinal tract in healthy donkeys (Equus asinus) in Egypt. Good knowledge of these standard and reference values of the wall thickness and motility pattern of gastrointestinal tract structures represents a step in the early diagnosis of the gastrointestinal disorders, including colic in such animal species.     

影响微种植钉支抗的临床稳定性因素研究

目的探讨微型种植钉作为增强支抗手段在临床应用中的稳定性,同时分析影响其成功率的相关因素,为今后的临床工作提供参考.方法 53例错颌患者共植入微型种植钉171枚,观察期1 a,并分析年龄、性别、下颌平面角、牙周组织肿胀、牙周炎史等因素对微型种植钉稳定性的影响.结果本组53例错颌患者的微型种植钉总成功率为90.57%（48/53）,其中患者的口腔卫生状况、牙周组织肿胀、牙周炎史、下颌平面角等是微型种植钉成活率的独立影响因素,而且患者的年龄、性别以及微型种植钉的设计因素对微型种植钉成功率的影响无显著性差异,不具有统计学意义（P〉0.05）.结论采用微型种植钉作为增强支抗手段的患者要注意保持口腔清洁,同时医师要根据患者的下颌平面角设计种植方案,避免牙周组织肿胀的发生,以提高微型种植钉的成功率.     

Effects of pyriproxyfen, a juvenile hormone analog, on development of the mealworm, Tenebrio molitor

Pyriproxyfen, an analog of the juvenile hormone (JH) in insects, has been evaluated in vivo and in vitro on an important stored product pest, the mealworm Tenebrio molitor. On newly ecdysed pupae, this insect growth regulator (IGR) was applied topically (at 0.10 and 0.20 μg/insect). Enzyme immunoassay measurements showed a decrease of the ecdysteroid titer in the hemolymph of treated specimens. In addition, the treatment induced an increase of the protein concentration in the hemolymph, however, there was no significant effect on the protein band pattern. Using in vitro pupal integument explant cultures, pyriproxyfen (at 1 and 10 μM in the medium) caused a significant inhibition of ecdysteroid amounts and of the thickness of new cuticle secreted. These new results are discussed in relation to the physiology of this IGR with a JH action.