Seasonal Changes in the Milt Quality of Waigieu Seaperch,Psammoperca waigiensis: Implications for Artificial Propagation

Milt quality of Waigieu seaperch was sampled at the beginning, the middle, and the end of the spawning season to assess if the sampling season has an effect on milt quality parameters. The milt volume and total sperm production were higher at the middle of the spawning season while the sperm concentration in milt was significantly higher at the beginning and the end of the spawning season. Sperm morphology and the major parameters of seminal plasma (pH, total protein, Mg²⁺, or Ca²⁺ concentrations) did not differ throughout the spawning season. The concentrations of Na⁺ and the osmolality increased throughout the spawning season. The percentage of motile cells did not differ during the spawning season while the duration of sperm motility (swimming duration) and velocity (swimming speed) were significantly different during the spawning season. The fertilization rate (75.7 ± 6.8%) and hatching rate (56.5 ± 3.1%) at the middle of the spawning season were higher than at the beginning and end periods. Results indicated that milt quality parameters and fertility success in the middle of the spawning season were higher compared to earlier and later sampling dates. Thus, we recommend collecting milt during this time for maximal fertilization and hatching success.     

Fate of Escherichia coli and Escherichia coli O157 in soils and drainage water following cattle slurry application at 3 sites in southern Scotland

Abstract. Slurry from farm animals may contaminate water supplies, rivers and bathing waters with faecal coliforms, such as Escherichia coli . Where animals harbour the O157 strain the hazard to human health is particularly high, but both the hazard level, and the low incidence and sporadic nature of the excretion of E. coli O157 make it difficult to study this strain under field conditions. The survival of total E. coli and of E. coli O157 were compared in the laboratory for two soils under controlled temperature and moisture. E. coli O157 die-off rate was the same as or quicker than for total E. coli . This result meant that field experiments studying the fate of total E. coli should give a satisfactory evaluation of the risk of water contamination by the O157 strain. In four field experiments at three sites, slurry containing total E. coli numbers of 2.2 × 10⁴ to 5.7 × 10⁵ colony forming units per mL (c.f.u. mL^–1) was applied to drained field plots. Field die-off was faster than expected from laboratory experiments, especially in one experiment where two weeks dry weather followed application. In all but this experiment, the first drain flow events after slurry application led to very high E. coli concentrations in the drains (10³ to 10⁴ c.f.u. mL^–1). E. coli O157 was present in the slurry used for two of the experiments (33 c.f.u. per 100 mL in each case). However the proportion of E.coli O157 was very low (about 1 in 10⁵) and it was not detected in the drainage water. After the first week E. coli drainage water numbers decreased rapidly but they were 1–10 c.f.u. mL^–1 for much of the sampling period after slurry application (1–3 months).     

中国平背树螽属两新种(直翅目:螽斯科:树螽亚科)

描述了平背树螽属2新种,定名为双刺平背树螽(Isopsera bicuspidota Yang etKang)和广西平背树螽(I.guangziensis Yang et Kang)。     

Biochemical Changes in Freshwater Prawn Macrobrachium rosenbergii During Larval Development

Abstract.— Quantitative changes in the protein, lipid and carbohydrate were studied in the early larval stages of developing freshwater prawn Macrobrachium rosenbergii reared under fed and starved conditions to understand the relative importance of these nutrients in energy metabolism of the growing larvae. Larvae obtained from several females were stocked into three 250-L tanks at a density of 30 larvae/L. The feeding regime consisted of newly hatched Artemia nauplii. Protein was always the major organic constituent followed by lipids and then carbohydrates of both fed and starved larvae. Protein levels of both fed and starved larvae increased during development, suggesting an important role in morphogenesis. The decline of lipid during the larval growth that was more rapid for starved larvae, suggests a probable utilization of lipid as the major metabolic source of energy. Carbohydrates formed less than 5 and 2.4% of the larval dry weight of fed and starved larvae, respectively, suggesting their limited role in larval metabolism.     

17β-雌二醇-ARIS构建及其标准曲线的质量评估

以 1 7β-雌二醇 -黄素腺嘌呤二核苷酸结合物为标记物 ,以葡萄糖氧化酶为全酶 ,建立了 1 7β-雌二醇脱辅基酶再激活免疫测定系统 (1 7β- E2 - ARIS) ,完成了两条标准曲线的制作 ,通过 logit代换法对两条标准曲线进行了直线回归。两条标准曲线的拟合度 (r)分别为0 .996 7* * 和 0 .9991 * * ,灵敏度分别为 1 1 .5 4pg· m L- 1 (2 . 31 pg·孔 - 1 )和 1 4.88pg·m L- 1 (2 . 98pg·孔 - 1 ) ,平均变异系数(CV% )分别为 4.6 4%和 9.34% ,测定范围为 31 .2 5～ 1 0 0 0 pg·m L- 1 。     

江西省古树资源系统研究报告

研究对象只限于散生于江西省山下及村落的30851株古树，不涉及自然保护区、森林公园中的古树。根据古树生长特征，分析其时间分布(古树级及树龄)、空间分布(设区市分布、县域分布)，借助于动态聚类统计分析方法从不同方向进行数量分类，并对数量分类成果用判别分析进行检验。最后对各县域每km^2和每万人负荷古树数进行核算，用数据资抖说明县域保护古树的重要性，增强县域保护古树的责任感。     

17β─雌二醇主动免疫对公兔生殖的影响

以１７β－雌二醇－６－人血清白蛋白对新西兰公兔进行主动免疫，用ＲＩＡ检测抗体滴度和１７β－雌二醇及睾酮浓度，并检测睾丸重量和间质细胞面积。结果，试验组各兔均不同程度地产生了１７β－雌二醇抗体，其血浆１７β－雌二醇浓度极显著地低于对照组〔（２０．３±２１．６）ｎｇ／Ｌ，（１６７．７±４９．６）ｎｇ／Ｌ，Ｐ＜０．００１〕，睾酮浓度极显著地高于对照组〔（７．３±７．１）μｇ／Ｌ，（０．５２±０．２９）μｇ／Ｌ，Ｐ＜０．０１〕。每侧睾丸重量和间质细胞面积均极显著地大于对照组〔（３．９４±０．９３）ｇ和（２５２．２５±８５．７８）μｍ２，（２．９８±０．７２）ｇ和（１６１．７９±３６．４５）μｍ２，Ｐ＜０．０１和Ｐ＜０．００１〕。提示１７β－雌二醇主动免疫可望成为提高雄性动物生育力的有效途径之一     

Effects of timing and size of daylength change on brown egg laying domestic hens: Plasma luteinising hormone concentration and sexual maturity

1. Brown egg laying pullets were transferred from an 8‐h photoperiod to an 8‐, 10‐, 13‐ or 16‐h photoperiod at 6, 9, 12, 15, 18 or 20–3 weeks of age. Plasma luteinising hormone (LH) concentrations were measured at transfer and 7 and 14 d afterwards.

2. Significant increases in plasma LH occurred following light stimulations at 6, 9 and 12 weeks of age.

3. Changes in LH concentration 7 d after a light increase from 8 h to 8, 10, 13, 16 h were highly correlated with photoperiod length at 9 and 12 weeks of age.

4. Changes in LH were generally poorly correlated with age at sexual maturity, although the reduced influence on age at first egg of a light increase given close to sexual maturity was reflected in minimal LH responses at 18 and 20.3 weeks.     

An economic evaluation of the differences between intensive and extensive beef production systems

A model to evaluate economic criteria involved when cattle are raised on high-forage diets prior to finishing or finished directly after weaning was developed using data from two experiments. In Exp. 1, each year for 3 yr, 136 Charolais-cross calves were weaned and allotted to either an intensive system, in which they were immediately finished on a high-grain diet, or an extensive system, in which they were wintered on crop residues, grazed on summer pasture and finished on a high-grain diet. In Exp. 2, 160 British breed steers were wintered, in one of eight different wintering systems utilizing crop residues, using supplemental protein and(or) alfalfa hay. After wintering, the steers grazed summer pasture and then were finished on a high-grain diet. Overall cost of gain and final "break-even" price were lower for cattle finished through the extensive system except when the price of corn was very low in relationship to other inputs. Interest costs were higher for cattle in the extensive system. Increasing the feeder calf purchase price had almost no effect on differences between the systems. Corn price and purchase price affected both systems similarly, whereas interest rate, wintering yardage and finishing yardage affected each system differently. Because of the additional weight produced through the extensive system, it yielded lower final "break-even" prices in most situations.