我国汽车零部件再制造产业的发展瓶颈与建议

本文介绍了我国再制造工程和汽车零部件再制造产业的市场潜力,从政策法规等方面探讨了制约产业发展的瓶颈,并在此基础上提出了促进我国汽车零部件再制造产业发展的几点建议.     

边鸡胰岛素生长因子结合蛋白-3基因外显子2MspⅠ位点对繁殖性状的遗传效应分析

本研究采用PCR-RFLP技术检测边鸡类胰岛素生长因子结合蛋白-3(insulin-like growth factor binding proteins-3,IGFBP-3)基因外显子2 MspⅠ位点的单核苷酸多态性,并与边鸡的繁殖性状进行相关分析。结果表明,在边鸡IGFBP-3基因的1087 bp处检测到1个C→T的突变,显示3种基因型(CC、CT和TT),C等位基因为优势等位基因。最小二乘分析结果表明,CT基因型的开产体重显著高于CC基因型(P<0.05)。不同基因型对其余4个繁殖性状(开产日龄、开产蛋重、300日龄产蛋数及300日龄蛋重)均无显著影响(P>0.05)。     

小黑杨胸径和树高的生长动态

以张家口市坝上地区张北县、沽源县无性繁殖苗造林的小黑杨为研究对象,采用树干解析法获取3种方式繁殖(插条、断根和埋桩)造林的小黑杨的树高和胸径生长数据,利用Richards生长曲线方程和加权平均法,比较分析小黑杨胸径和树高生长,结果表明:1)3种不同方式繁殖的苗木胸径生长曲线均呈“S”状,有较高的相关性; 2)利用Richards生长曲线推测出的胸径值表现为断根小黑杨>埋桩小黑杨>插条小黑杨; 树高推测值表现为埋桩小黑杨≈插条小黑杨>断根小黑杨。     

哈尔滨白条草蜥的两性异形和雌体繁殖

为比较白条草蜥不同种群形态和繁殖特征的地理变异,于2011年和2012年的4—8月,通过野外捕捉、实验室饲养的方法,对黑龙江省哈尔滨地区的白条草蜥(Takydromus wolteri)种群的两性异形和繁殖输出进行研究。结果表明：白条草蜥的哈尔滨种群具有明显的两性异形现象,雌性和雄性平均体长分别为55.86 mm和52.13 mm,雌性的体长显著大于雄性(F_1,62=15.337,P＜0.001)。去除体长的影响,雌性具有较大的腹长(F_1,61=4.937,P＜0.05),雄性具有较大的头部（头长：F_1,61=103.56,P＜0.001;头宽：F_1,61=68.524,P＜0.001）;较大的雌性具有较高的年生殖力(r=0.732,F_1,18=20.821,P＜0.01)和年繁殖输出(r=0.681,F_1,18= 15.579,P＜0.01)。与以往研究相比,白条草蜥的两性异形现象具有明显的地理变异,北方的哈尔滨种群两性的体长均明显大于南方的滁州种群两性的体长,符合贝格曼定律。     

水牛营养研究新进展

水牛在中国南方农业产业结构中占有非常重要的地位,大部分水牛都属于沼泽型水牛,长期以来作为役用家畜在广大农村分散饲养。随着中国农业机械化程度的提高,水牛在农村扮演劳役的角色逐渐发生了改变,水牛将由单一的役用向乳用和乳肉兼用方向发展。文章从水牛营养需要、饲料资源开发与利用、水牛瘤胃微生物与瘤胃发酵、水牛营养与繁殖,以及水牛乳、肉品质的营养调控等方面对近20年来水牛营养方面的研究进展进行了综述。     

Modelling salmon lice,Lepeophtheirus salmonis,reproduction on farmed Atlantic salmon,Salmo salar L

The aim of this study was to model sea lice levels and the effect on reproduction by a stochastic simulation model and to evaluate the uncertainty of lice estimates based upon counts. Two empirical data sets were examined to parameterize the models. An overall fit of the data to the Poisson distribution was found and thus was used as the base of the stochastic models. In the model, salmon lice reproduction is not linear with the number of adult females and at low lice loads a smaller proportion of the adult female lice will reproduce. Depending on the variance structure, it was estimated that between 40% and 60% of the adult female lice will reproduce at an abundance of 0.5 adult females per fish. Lice counts, especially when examining few fish at low lice loads, are uncertain and at a true abundance of 0.1 one may count between 0 and 5 lice when examining 10 fish. Understanding the dynamics of sea lice reproduction is a key factor in the development of sustainable control strategies.     

On the breeding behaviour and reproduction of the freshwater prawn,Macrobrachium rosenbergii (de Man 1879) (Decapoda‐Crustacea) under laboratory conditions

The giant freshwater prawn, Macrobrachium rosenbergii is one of the most common decapod species, and now getting more attention from the aquaculturists world wide due to its high market demand. It is commercially important because of its size as well as its eating flesh qualities. The breeding behaviour, reproduction and hatching of this species were observed for about 8 months during 2009. Juveniles (0.55 ± 0.177 g total weight and 2.7 ± 0.12 cm, total length) were reared in rounded fibre glass tanks (1.3 m, diameter). Pre‐mating moult occurs in prawns once the ovaries ripen in their carapace cavity so as to transform the prawn into berried stage. Recorded incubation period ranged from 18 to 24 days. The number of eggs ranged from 2050 to 150 500 and the fecundity ranged from 435.2 to 3849.1 eggs. Number of hatched larvae ranged from 1825 to 123 410 larvae for females of 4.71 to 39.1 g respectively. The number of eggs carried by female prawn was directly proportional to its body weight (no. of eggs = 3441.3 wt. of female – 32 292, r² = 0.819). (fecundity = 82.066 wt. of female ? 235.04, r² = 0.7779; fecundity = 317.86 length of female ? 2651, r² = 0.833). Hatching rate ranged from 65% to 91%, and there was a correlation between number of hatched larvae and size of female parent (no. of larvae = 10 369 length of female – 102 965, r² = 0.8159; no. of larvae = 2792.9 wt. of female – 26 268, r² = 0.829). This study can greatly help in the management strategies of prawn hatcheries and improve its hatching technology.     

Feeding the pearl oyster Pinctada margaritifera during reproductive conditioning

This study aimed to model the food intake of P. margaritifera to examine the relationship between food level and reproductive activity. The effect of microalgae concentration on ingestion rate and assimilation efficiency was studied over a broad concentration range, using a mixture of Isochrysis galbana and Chaetoceros gracilis. Reproductive effort was assessed using three microalgae concentrations of 0.5, 7 and 18 cell μL^?1. Reproductive status was assessed by gonad development index (GDI) – the ratio of the gonad surface to the visceral mass surface – and histological analysis of the gonad based on the presence (continuous or discontinuous) or the absence of gonial cells (GC). Ingestion is a saturating function of seston concentration for bivalves modelled with an adapted Michaelis‐Menten function. The maximum ingestion rate of P. margaritifera adults was 193.50 × 10⁶ cell h^?1 g^?1 dw and the half saturation coefficient was 15 cell μL^?1. The concentration of 18 cell μL^?1, supplied for 45 days, induced a significantly higher GDI than the other treatments. GC decreased significantly and even stopped when pearl oysters were under‐fed, suggesting that the mitotic process of the germinal stem cells was altered. Differentiation of germinal stem cells therefore appears to be controlled by food availability.     

金沙江下游中华沙鳅的资源现状、繁殖特性及人工繁育的初步研究

2011年5～12月,对金沙江屏山以下江段中华沙鳅(Botia superciliaris)的资源现状、繁殖特性进行了调查,并在实验室对该鱼的人工繁育进行了探索。所获中华沙鳅雄鱼(n=251)平均体长81.3 mm,平均体重8.7 g;雌鱼(n=486)平均体长109.7 mm,平均体重15.9 g。屏山调查点中华沙鳅占总渔获物(尾数)的2.68%,日均单船产量平均为0.12 kg;安边调查点中华沙鳅占总渔获物(尾数)的0.17%,日均单船产量平均为0.06 kg。雌雄性比为1.31∶1;雌、雄最小性成熟年龄均为2+龄。雌鱼的绝对怀卵量最大值为5 948粒,平均为4 455粒。中华沙鳅属一次性产卵类型,在流水中产漂流性卵;繁殖高峰期在5～6月。人工繁育时,受精卵在水温25～26℃孵化29 h仔鱼出膜,孵化率约70%,刚出膜仔鱼全长4.9～5.1 mm。半年后幼鱼的成活率为11.13%,全长约30 mm。     

A new classification of pre‐ovulatory oocyte maturation stages in pikeperch,Sander lucioperca (L.), and its application during artificial reproduction

This study aimed at improving the reproduction effectiveness and synchronization of ovulation in the pikeperch, Sander lucioperca (L.), during induced spawning, which is one of the main bottlenecks in the aquaculture of this species. For this purpose, a new categorization of maturation stages in pre‐ovulatory oocytes was applied. It is generally based on two morphological indicators: germinal vesicle migration or its breakdown (GVBD) and different oil droplet coalescence rates. This categorization covered seven stages (from I to VII) – from the end of vitellogenesis to ovulation. The categorization was verified by controlled reproduction with the use of hormonal stimulation (500 IU of hCG per kg of female body weight) and low spawning temperature (12 °C), which extended the latency time. In addition, some morphological indicators (pseudo‐gonadosomatic index, Fulton's condition coefficient) of females were calculated in order to determine their usability in determining the maturation stage. However, these indicators proved to be ineffective for this purpose, further highlighting the need to determine the maturational stages in pre‐ovulatory oocytes to synchronize ovulation in pikeperch. During the experiment, ovulation seemed to be synchronized among the experimental treatments. Statistical differences were found in terms of latency time between experimental groups at different maturity stages (II – 78–98 h; III – 57–78 h; IV – 48–58 h; V – 32–49 h; VI – 5–30 h) according to the proposed classification. This classification and the results presented in the study significantly improved the synchronization of ovulation, which may positively affect the effectiveness of pikeperch production under controlled conditions.