基于地统计学和GIS的喀斯特烟田土壤肥力综合评价——以贵州省毕节地区为例

以贵州省典型的喀斯特地区———毕节地区为研究区域,利用地统计学和GIS相结合的方法,对烟田土壤肥力进行综合评价。在确定评价因子隶属函数和权重的基础上,建立土壤肥力综合评价指标(IFI)。通过对土壤肥力综合评价指标进行半方差函数分析和普通克里格法(Kriging)最优内插,绘制了毕节地区烟田土壤肥力综合评价指标的空间分布图。描述性统计结果表明,毕节地区烟田土壤肥力综合评价指标值为0.35～0.92,变异系数为14.25%。半方差函数分析表明,毕节地区烟田土壤肥力综合评价指数的最适模型是指数模型;块基比为30%,表明具有中度空间相关性;烟田土壤肥力综合评价指数在空间分布上总体呈从内到外递减的趋势,其中以0.63～0.72和0.72～0.92范围内的面积较大,分别占到总面积的68.20%和20.63%。由此表明,该研究区域大部分土壤肥力状况良好。     

Effect of feeding frequency and feeding time on growth of Penaeus vannamei (Boone)

Abstract. An intensive growth trial conducted In pens in an earthen pond indicated that growth of Penaeus vannamei (Boone) increased with feeding frequency and suggested that day feedings produce greater growth than night feedings. The differences in growth due to feeding frequency were significant, instantaneous growth rates (IGR) increasing from 1·62% to 1·66% to 1·71%/day as the number of feedings increased from one to two to four per 24 h. Comparison of the IGR of shrimp fed at night (1·64%/day) to that of shrimp fed during the day (1·68%/day) suggested ( P = 0·0633) that growth was greater for shrimp given day feedings than for shrimp given night feedings. Survival of shrimp was not significantly different due to feeding frequency or due to time of feeding and averaged 74·7 ± 6·1%. Results indicate that P. vannamei cultured under conditions similar to those tested should be fed a minimum of four times daily and suggest that feeding during the day is at least as good as and may be preferable to feeding at night.     

牧区饲草储备量与牲畜出栏率的直线回归分析

饲草料储备量与牲畜出栏率之间存在着回归关系,建立回归方程;Y=-1.79 1.6x,预测和防止冬季牲畜缺草而形成的牲畜损失。     

Functional and Rheological Properties of Amaranth Albumins Extracted From Two Mexican Varieties

The functional and rheological properties of amaranth albumins isolates extracted from two new Mexican varieties were determined. Functional properties tested were protein solubility, foaming, water and oil absorption capacities, emulsifying activity, and emulsion stability. The maximum solubility values for both amaranth albumins were found above pH 6 and values were compared to the solubility of egg albumins. Albumins from amaranth showed excellent foaming capacity and foaming stability at pH 5, suggesting that this protein could be used as whipping agents as egg albumins, also the water and oil absorption capacities reached their maximum values at acidic pH, suggesting that amaranth albumins could be appropriate in preparation of acidic foods. The rheological test based on farinograms and alveograms showed that wheat flour supplemented with 1% amaranth albumins improves the dough properties due to higher mixing stability and the bread had better crumb characteristics. In addition of the known high nutritional values of amaranth albumins, our results indicate the high potential for use of these proteins as an ingredient in food preparations.     

Mechanical wounding induces the formation of extensive coated membranes in giant algal cells

Mechanically wounding giant cells of Boergesenia forbesii induces the formation of bristle-coated, plasma-membrane invaginations (coated pits) and coated vesicles, easily providing a plentiful source of coated membranes in a clean cellular system unencumbered by other tissues. Contractions evoked by wounding partition the cytoplasm into hundreds of spherical protoplasts with approximately 40 percent less total plasma-membrane surface area than the original cell. Ferritin labeling and the appearance of numerous large coated pits and vesicles at the peak period of contraction indicate that these organelles play a role in extensive endocytosis of the plasma membrane.     

不同季节牧草钙磷含量对放牧绵羊血清骨钙素的影响

研究了不同季节牧草钙磷含量对放牧绵羊血清骨钙素、碱性磷酸酶、血清钙、无机磷、血清钙磷比和血清钙磷乘积的影响。结果表明:这些血清指标随季节变化明显,血清骨钙素夏季含量为(2.009±0.888)ng/mL,极显著的低于冬春季(3.974±1.281)ng/mL和秋季(3.279±1.365)ng/mL的含量(P<0.05)。从相关分析中看出,骨钙素与AKP、血钙、无机磷、血钙/磷和血钙磷乘积呈正相关,相关系数分别为0.047、0.546、0.035、0.394、0.489。与牧草钙、磷和钙磷比呈负相关,尤其与牧草钙的相关系数达-0.657(P<0.01)。利用逐步回归的方法得出的骨钙素与牧草钙、血清钙的多元回归方程为:骨钙素=1.813-2.358牧草钙+0.945血清钙(P<0.05)。认为血清骨钙素可以作为反映放牧绵羊钙磷盈缺状况的灵敏指标。     

海西地区人工草地生产布局探讨

海西地区指州辖天峻县、乌兰县、都兰县、德令哈市、格尔木市以及西部大柴旦、冷湖、茫崖三镇,覆含柴达木盆地。畜牧业是海西州支柱产业之一,草地是其发展的基础,畜牧业发展需要人工草地生产支持,科学布局人工草地对于安全高效发展草地畜牧业具有积极重要的现实意义。     

Utilization of soybean meal as an alternative protein source in the Mediterranean yellowtail, Seriola dumerili

The availability of defatted soybean meal as a substitute for fish meal was evaluated in juvenile (450 g on average) yellowtail fed diets containing several levels of soybean meal (from 20 to 50%). After 153 days, liveweight averages were 980, 925, 795 and 670 g for fish fed diets in which fish meal was partially substituted with 20, 30, 40 and 50% soybean meal, and feed conversion ratios were 2.79, 3.09, 4.57 and 6.52, respectively. Regression analysis showed a negative effect of inclusion of soybean, although fish fed diets containing 20% and 30% of soybean did not present statistical differences and grew significantly more, and had a better feed conversion ratio, than fish fed 40 or 50% diets. Likewise, muscle protein level was lower and lipid content was higher in fish fed 20 or 30% soybean. No differences were obtained for protein digestibility coefficients of experimental diets.