Effects of dietary electrolyte balance on the chemistry of blood and urine in lactating sows and sow litter performance

One hundred fifty-three sows (average parity of 2.2) were used to determine the effects of dietary electrolyte balance (calculated as mEq/kg of diet for Na + K - Cl) on sows and their litters during lactation. The sows were fed corn-soybean meal-based diets (1.0% lysine, 1.0% valine, 0.95% Ca, and 0.80% P; as-fed basis) starting on d 109 of gestation and throughout the 21-d lactation experiment. Dietary electrolyte balance (dEB) was 0, 100, 200, 350, and 500 mEq/kg (as-fed basis), well above and below the dEB of 185 mEq/kg found in a simple corn-soybean meal-based lactation diet. To achieve the desired dEB, diets had the following: 1) 1.8% HCl (6 N) and 1.06% CaCl2, 2) 1.0% CaCl2, 3) 0.04% NaHCO3, 4) 1.29% NaHCO3, and 5) 2.54% NaHCO3 (as-fed basis). Increasing dEB increased blood pH (linear and quadratic effects, P < 0.001), partial pressure of carbon dioxide (linear effect, P < 0.001), HCO3- concentration (linear and quadratic effects, P < 0.001), and blood base excess (linear and quadratic effects, P < 0.001). However, increased dEB resulted in lower blood concentrations of K (linear and quadratic effects, P < 0.04), Cl (linear and quadratic effects, P < 0.001), and ionized Ca (linear and quadratic effects, P < 0.001). Changing dEB did not affect ADFI; water usage, litter weight gain; sow weight change; sow backfat change; percentages of CP, lactose, and fat in the milk; percentage of sows returning to estrus; days to estrus; and number of pigs born alive in the subsequent litter (P = 0.06). However, piglet survivability to d 10 and overall was greatest with the lower dEB treatments (linear effect, P < 0.05). The pH (linear and quadratic effects, P < 0.001) and colony forming units of total bacteria (linear effect, P < 0.03) in the urine increased as dEB of the diet was increased. In conclusion, dEB had pronounced effects on the physiological status of sows and decreasing dEB below that in a simple corn-soybean meal-based diet decreased bacterial counts in the urine and increased piglet survivability. However, milk composition, sow and litter weights at weaning, and subsequent rebreeding performance of the sows were not affected by dEB.     

冬小麦品种‘兰天23号’苗期抗条锈性遗传分析

2014年在甘肃省农业科学院植物保护研究所兰州温室,进行了‘兰天23号’/‘铭贤169’组合的亲本及其F1、F2、BC1代对条锈菌主要流行小种CYR32、CYR33及新菌系G22-9的遗传分析。结果表明,接种CYR33,F2代植株抗感分离比为144R∶54S,符合3R∶1S的理论比值;接种CYR32,F2代植株抗感分离比为62R∶22S,符合3R∶1S的理论比值;接种G22-9,F2代植株抗感分离比为85R∶24S,符合3R∶1S的理论比值;F1代植株对供试菌系均表现免疫,BC1代植株抗感分离比均符合1R∶1S的理论比值,表明‘兰天23号’对3个供试条锈菌系的抗病性均由1对显性抗性基因控制。通过系谱分析推知,该抗病基因来源于抗病亲本‘SXAF4-7’。     

豇豆生产使用不同类型肥料的效果

肥料除了对作物有增产的效果外,在改良土壤结构、维持土壤营养相对平衡方面的作用也不容忽视。众所周知,过量施用化肥能降低土壤肥力,还会引起环境污染。本研究采用不同类型的肥料进行对比试验,探讨肥料对土壤肥力状况变化的影响,为蔬菜生产合理选择肥料提供依据。1　材料与方法1. 1　材料　供试蔬菜品种为丰产 3号豇豆,由广东省农业科学院蔬菜研究所提供, 2003年 3月 28日直播于大田。1. 2　方法　试验在广州市番禺区万顷沙进行,设 3个处理,处理 1 (对照 ):每小区基施挪威复合肥(N-P-K: 15-15-15)1. 7kg 过磷酸钙 7. 5kg,追施复合肥(…     

甘薯膨大素对慈菇生长发育的影响

施用甘薯膨胀大素可改善慈菇营养生长状况,促进慈菇球茎的膨大,球茎开始膨大时叶面喷施甘薯膨大素,可显著增加早期产量;定植时及球茎开始膨大时２次施用甘薯膨大素,早期产量增加不显著,总产量显著增加。     

辣(甜)椒抗黄瓜花叶病毒(CMV)研究进展

黄瓜花叶病毒病(CMV)是为害辣(甜)椒的重要病毒,国内外对其研究较多。通过综述CMV的株系分化、抗性遗传、分子标记、抗CMV基因工程以及抗CMV育种等方面的研究结果和报道,旨在为辣(甜)椒抗CMV育种提供参考依据。     

小菜蛾抗药性研究进展

综述了小菜蛾抗药性的发展，抗性的消长规律，对不同种类农药的交互抗性及抗性对策。     

Water retention capacity of typical roof greening matrices

The water retention capacities of commonly used roof greening matrices, concluding ceramsite, peat and super absorbent polymer, under fully saturated, cyclic wetting-drying and natural evaporation conditions were studied. The saturated water retention capacity of matrices were obtained by vacuum saturated test. It showed that the fully measured saturated degree of saturation of mixed matrix was greater than that calculated by the combination of all components. The reason which increases the water contents to porous skeleton was analysed. In cyclic wetting-drying tests, the water retention capacities of ceramsite and peat were almost unchanged. However, due to the main molecular chain broken under drying in relatively high temperature, the water retention capacity decreased rapidly after several wetting-drying cycles. In natural evaporation tests, the evaporation rates of ceramsite, peat, super absorbent polymer and free water were almost identical in the condition of high water content. As the water content decreasing, the evaporation rate of the matrix which had lower water retention capacities decreases faster. The matrix with a reasonable proportion of super absorbent polymer can remarkably improved its water retention capacity.     

水稻胚乳细胞增殖和充实与子房生理活性变化关系的研究

结合水稻不同粒位籽粒的胚乳增殖动态和单细胞充实状况,分析了胚乳细胞增殖过程中子房若干生理指标的变化特点,结果表明：籽粒呼吸量较大的时期为胚乳细胞物质充实期,而单位鲜重呼吸强度最大在胚乳细胞分裂期,弱势粒呼吸强度在花后有一低水平期,随着细胞分裂的起动开始上升;胚乳细胞分裂期保持有较物质充实期高得多的含水率;子房ＡＴＰ水平在胚乳细胞分裂期处于较高水平;可溶性糖含量强势粒在胚乳细胞分裂期水平较高,至细胞     

基因型和供体植株生长环境对大白菜游离小孢子胚胎发生的影响

１７个用于大白菜常规育种的基因型在ＮＬＮ－１３液体培养基中进行游离小孢子培养，结果有１６个基因型经由小孢子胚胎发生途径获得小孢子胚。这些基因型包括从早熟晚熟的各种类型。各基因之间在小孢子胚胎发生频率方面存在很大差异，产量最高的两个基因型Ｔ１１和ＣＣ１１，平均每百花蕾分别达３５９２８和３４１３２个胚。供体植株生长环境对小孢子胚胎发生具有明显影响；在１０／２０℃（液／昼）的部分控温温室生长的供体植株，     

玉米种子纯度检验方法研究

本文阐述了检验玉米种子纯度的形态学方法、生理生化方法和分子生物学方法的研究及应用情况,并对各种方法的优缺点进行了述评.