Finding suitable growth models for turbot (Scophthalmus maximus L.) in aquaculture 1 (length application)

Growth data of two different commercial turbot (Scophthalmus maximus) strains reared in recirculating aquaculture systems were analysed with the aim to determine the most suitable model for turbot. To assess the model performance three different criteria were used: (1) The mean percentage deviation between the estimated length and actual length; (2) the residual standard error with corresponding degrees of freedom and (3) the Akaike information criterion. The analyses were carried out for each strain separately, for sexes within strains and for a pooled data set containing both strains and sexes. We tested a pre‐selection of six models, containing three to four parameters. Models were of monomolecular shape or sigmoid shape with a flexible point of inflection including the special case of monomolecular shape in defined cases of their parameters. The 4‐parametric Schnute model achieved best fit in 62% of all cases and criteria tested, followed by the also 4‐parametric generalized Michaelis–Menten equation in 48% and the 4‐parametric Janoschek model (38%). The von Bertalanffy growth function achieved only 29%, Brody 24% and a new flexible function 19% best fit. In a 1–1000 day growth‐simulation sigmoid shaped curves were produced by the Schnute model in 71% of cases. The Janoschek and the Michaelis–Menten model each produced sigmoid curves in 57% of all cases. This indicates that a flexible 4‐parametric function reflects the growth curve of turbot the best and that this curve is rather sigmoid than monomolecular shaped.     

大菱鲆幼鱼对饲料中泛酸最适需求量的研究

为研究大菱鲆(Scophthalmus maximus)幼鱼对泛酸的最适需求量，在基础配方中添加不同梯度的泛酸钙，制成6组泛酸含量分别为6.24、10.64、15.02、23.81、41.40和76.57 mg/kg等氮等能实验饲料，投喂初始体重为(24.73±0.10) g的大菱鲆幼鱼80 d。结果显示：1)泛酸对幼鱼成活率(SR)无显著影响(P>0.05)，10.64~76.57 mg/kg饲料组增重率(WGR)和特定生长率(SGR)显著提高(P< 0.05)；泛酸含量超过23.81 mg/kg时，肝体比(HSI)显著降低(P<0.05)；2)随着饲料中泛酸含量的提高，全鱼粗蛋白、粗脂肪和肌肉粗蛋白均呈先升后降趋势，肝脏脂肪含量显著下降(P<0.05)；3)肠道消化酶、Na+, K+-ATPase和肝脏胆碱酯酶(ChE)活力随泛酸添加量的增加呈先上升后下降趋势，10.64~76.57 mg/kg饲料组肠道肌酸激酶(CK)活力显著提高(P<0.05)；4)血清、肝脏中过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活力均呈先升后降趋势；6.24 mg/kg饲料组血清丙二醛(MDA)含量显著高于其他5组(P<0.05)；5)随泛酸含量的增加，肝脏脂肪合成酶(FAS)基因表达量先升后降，脂蛋白酯酶(LPL)基因表达量显著上升(P<0.05)。研究表明，饲料中添加适宜的泛酸能显著增强大菱鲆幼鱼肠道消化、吸收能力和机体抗氧化能力，并可提高脂肪代谢相关基因的表达水平，从而提高其生长性能。以增重率为判据，经折线模型拟合得出，初体重为24.73 g的大菱鲆幼鱼对泛酸的需求量为16.08 mg/kg饲料。     

红松幼龄材与成熟材力学性质的差异

本文研究了人工林和天然林红松幼龄材与成熟材力学性质的差异.结果显示,成熟材的所有力学性质均高于幼龄材.幼龄材与成熟材的抗弯弹性模量差异在人工林红松中达0.01水平显著,天然林红松也达到0.01水平显著;人工林红松抗弯强度和弦向横纹抗压强度差异达0.05水平显著.抗弯强度、顺纹抗压强度、横切面硬度和弦向横纹抗压强度4项指标的差异达0.05水平显著.     

中国主要人工林树种幼龄材与成熟材及人工林与天然林木材性质比较研究

本文对中国１０种人工林和４种天然林的幼龄材与成熟材及４个树种的人工林木材与天然林木材的构造特征、化学性质、物理性质、力学性质的３３项材性指标差异进行了比较研究。结果表明,在幼龄材与成熟材之间,在统计上表现出差异显著性的为幼龄材比成熟材生长轮宽,管胞列数多,管胞短,直径小,微纤丝角大,密度小,径向干缩小,差异干缩大,流体扩散性高,抗弯强度、抗弯弹性模量、顺纹抗压强度、径面顺纹抗剪强度、径面抗劈力和冲击韧性低等１５项,即４６％的测试项目差异显著;表明在木材加工和用作结构材时应将幼龄材和成熟材视作两个性质不同的总体来考虑,在培育结构材时应研究如何缩短幼年期或改善幼年期材性。在人工林与天然林木材之间,采取人工林幼龄材性质与天然林幼龄材性质相比,人工林成熟材性质与天然林成熟材性质相比,结果表明,多数性质在统计上差异不显著,只有人工林木材比天然林木材胞壁率小、顺纹抗压强度低、差异干缩大、流体扩散性高等４项,即只有１２％的很少数测试项目差异显著;表明有可能通过人工培育的方法培育出与天然林木材性质相近的木材。     

樟子松种源试验幼林期生长性状变异初探

对樟子松在五台，宁东，太白三个地点的苗期和幼林期的生长性状进行了分析。结果表明：不同种源间高生长存在极显著的差异，种源内个体变异也十分明显。高生长是随纬度增高而递减的渐变模式，而发芽率和发芽速度则无明显的地理变异。初步选择出生长良好，稳定性强的１３、１６、２０、１５、２号种源。     

Physiological response of temperature shocks in turbot and sole

In the present study, selected temperature drops were examined to investigate the effects of live chilling on stress and welfare in turbot and sole. This study demonstrated that rapid temperature drops from 11°C–12°C and 18°C–18.7°C to 4°C–0°C in turbot resulted in higher blood sodium and potassium at 0°C (164 mmol l^?1, 4.4 mmol ^?1) compared to 4°C (153 mmol l^?1, 3.1 mmol ^?1), indicating osmoregulatory disturbance. A rapid temperature drop from 18°C to 0°C in Senegal sole also resulted in higher blood sodium and potassium at 0°C (164 mmol l^?1, 4.8 mmol ^?1) compared to the control group at 18°C (157 mmol l^?1, 3.2 mmol ^?1). Based on present findings, we conclude that immersion in ice water will have a negative effect on the animal osmoregulatory capacity, and we recommend that turbot and sole are stunned before slaughter.     

The effects of dietary Eucommia ulmoides Oliver on growth,feed utilization,antioxidant activity and immune responses of turbot (Scophthalmus maximus L.)

The present study was conducted to evaluate the effects of dietary Eucommia ulmoides (EU) on growth, feed utilization, antioxidant activity and immune responses of turbot fed a basal diet (CON) or EU‐supplemented diets with 5.0 g/kg (EU1), 10.0 g/kg (EU2) and 20.0 g/kg (EU3) EU leaf powder. After 70‐day trial, EU supplementation did not affect nutrient utilization, but reduced feed intake (FI) and specific growth rate (SGR) of fish at doses above 5.0 g/kg. Superoxide dismutase (SOD), catalase (CAT) and total antioxidant capacity (T‐AOC) activities in the EU‐supplemented groups were significantly higher than those in the control group at a dose of 20.0 g/kg. Significantly reduced malondialdehyde (MDA) contents were observed in EU‐supplemented groups at doses over 5.0 g/kg. Furthermore, fish fed 20.0 g/kg EU showed the highest lysozyme (LZM) activity among groups. The EU‐supplemented diets with doses above 5.0 g/kg significantly enhanced the mRNA expressions of cytokines. The expression level of major histocompatibility complex II alpha (MHC IIα) was significantly upregulated compared to that of the control fish when the supplemental level was at 20.0 g/kg. Taken together, the present study indicated that the EU could remarkably enhance the antioxidant activity, non‐specific immunity and maintain an active immune response in turbot.     

Taurine alone or in combination with fish protein hydrolysate affects growth performance,taurine transport and metabolism in juvenile turbot (Scophthalmus maximus L.)

The study was conducted to investigate the effects of taurine (Tau) alone or in combination with fish protein hydrolysate (FPH) on growth performance, the expression of Tau transporter (TauT) and metabolic profile in juvenile turbot. FM, FPH0, FPH0+T, FPH10 and FPH10+T diets, respectively, contained 300, 150, 150, 80, and 80 g/kg fishmeal. FPH10 and FPH10+T diets contained 62 g/kg FPH. FPH0+T and FPH10+T diets were, respectively, prepared by supplementing the FPH0 and FPH10 diet formulations with 8 g/kg Tau. Specific growth rate was the highest in FM group and the lowest in FPH10 group. TauT mRNA levels in fish fed Tau supplemented diets were significantly lower than that in Tau unsupplemented diets. NMR‐based metabolomics analysis showed that Tau contents in liver of FPH0+T and FPH10+T were significantly higher than that of FM, FPH0 and FPH10. In muscle, Tau contents were significantly decreased in the FPH10+T versus FPH0 and the FPH10+T versus FPH10 comparisons. In conclusion, 62 g/kg FPH to replace fishmeal may not affect Tau synthesis, transport and metabolism. However, Tau supplemented alone or in combination with a certain level of FPH could reduce the requirement for Tau synthesis and transport and increased Tau levels in muscle and liver.     

论青少年体质健康的耗散结构*

目的：从耗散结构理论的角度研究解决我国青少年体质健康普通下降的严重问题，对解决我国青少年体质健康问题不仅具有独特的理论价值，而且具有显著的实践意义。方法：理论思辨法和逻辑分析法。结论：1.青少年体质健康普通下降的重要原因是其系统的耗散结构无法形成；2.解决青少年体质健康问题的重要途径在于促进其系统的耗散结构形成；3.开放性,远离平衡与非线性是青少年体质健康系统形成耗散结构的前提；4.满足青少年自我实现的愿望和体育锻炼的需求是青少年体质健康系统能够形成耗散结构的关键。