Sexual dimorphism of fast muscle fibre recruitment in farmed Atlantic halibut (Hippoglossus hippoglossus L.)

Commercially farmed Atlantic halibut (Hippoglossus hippoglossus) were reared at the Aga Marin's facility located on Dønna (Norway) under ambient environmental conditions in duplicate 15 × 15 × 8 m netpens (May 2004 to May 2005). Twenty fish were sampled five times over a twelve month production period during which time the average body weight increased from 1.26 to 2.08 kg (n = 100 fish). Body mass, fork length (L_F), and the number and size distributions of fast muscle fibres were determined in male and female fish. All males matured during the autumn whereas no maturation was observed in females. From the point of maturation females had superior growth performance to males and body mass and the total cross-sectional area of muscle were 1.4-fold (P < 0.05) and 1.3-fold higher (P < 0.01) respectively by May 2005. The total number of fast muscle fibres per trunk cross-section at 0.55 L_F was 24.5% higher in females (7.58 × 10⁵) than males (5.80 × 10⁵) prior to sexual maturation. In females, muscle fibre recruitment slowed with short days and low water temperatures (< 6.5 °C), but had increased to 1.01 × 10⁶ by May 2005 (P < 0.001). In contrast, there was no growth and no increase in muscle fibre number in males following the onset of maturation. The distribution of muscle fibre diameters prior to maturation in males was also significantly different between male and female fish matched for L_F. The results illustrate a sexual dimorphism of muscle fibre recruitment patterns in Atlantic halibut and highlight the adverse affects of sexual maturation in males on muscle growth.     

Effects of species richness and functional groups on chemical constituents relevant for methane yields from anaerobic digestion: results from a grassland diversity experiment

Changes in livestock production systems have led to land‐use changes and abandonment, especially of semi‐natural grassland in agriculturally less favoured regions. The generation of energy from biomass of extensive, high‐diversity grasslands can be an alternative to their abandonment, and anaerobic digestion is one possible method for converting grassland biomass into energy. However, little is known about the effects of species richness (SR) and functional groups on chemical constituents relevant for anaerobic digestion and the resulting energy potential. In this study, changes in the herbage chemical constituents that are relevant for forage quality were studied along a well‐defined diversity gradient (one to sixty species) and across different combinations of functional groups (legumes, small herbs, tall herbs and grasses). Substrate‐specific methane yield (CH_4 sub) was estimated through the concentrations of forage‐quality parameters such as crude fibre (CF), crude protein (CP), crude lipid, nitrogen‐free extract and their documented digestibility values, as well as the respective methane yields. Results show that with increasing SR, the CF increased and CP decreased, even though these effects could not be fully disentangled from the presence of grasses. These trends led to a negative effect of SR on CH_4 sub, while the area‐specific methane yield (CH_4 area = CH_4 sub × biomass yield) increased due to a strong increase in biomass with increasing SR. The CH_4 sub was increased when legumes were present, and it declined with the presence of grasses. Generally, CH_4 sub and CH_4 area varied between functional‐group monocultures and all functional‐group mixtures.     

Improving cereal grain carbohydrates for diet and health

Starch and cell wall polysaccharides (dietary fibre) of cereal grains contribute to the health benefits associated with the consumption of whole grain cereal products, including reduced risk of obesity, type 2 diabetes, cardiovascular disease and colorectal cancer. The physiological bases for these effects are reviewed in relation to the structures and physical properties of the polysaccharides and their behaviour (including digestion and fermentation) in the gastro-intestinal tract. Strategies for modifying the content and composition of grain polysaccharides to increase their health benefits are discussed, including exploiting natural variation and using mutagenesis and transgenesis to generate further variation. These studies will facilitate the development of new types of cereals and cereal products to face the major health challenges of the 21st century.     

智能化沼气池粗纤维含量、微生物多样性及产气率相关性分析

为完善智能沼气池智能化控制系统,并对相关智能化沼气池运行提供理论基础,对智能化沼气池粗纤维含量、pH值、微生物多样性和产气率以及各因素间相关性进行分析研究,结果表明：相同发酵时间、不同发酵层的沼液粗纤维含量、pH值、微生物的多样性不存在显著差异;相同发酵层、不同发酵时间的沼液粗纤维含量、pH值、微生物多样性存在极显著差异;各发酵时间段内,最高产气率是6～16h时间段1.12m3·m -3·d-1,其次依次为14～24 h、0～6 h、24～48 h、48～72 h时间段;不同发酵时间产气率与粗纤维含量呈显著负相关,与pH值、Dsh指数、Jsh指数呈显著正相关。     

中纤板生产中红外水分测定仪在线检测应用影响因素浅析

通过在中密度纤维板生产线中TIR-E四光束红外水分测定仪的调试和应用，分析了可能影响其检测精度的一些因素，并提出了在使用中的注意事项。     

盐胁迫下胡杨和毛白杨叶细胞中的离子区隔化

该文以抗盐的胡杨和盐敏感的毛白杨组培再生苗为实验材料,利用X--射线微区分析技术研究盐胁迫下(为期20d的盐处理)叶片各种类型细胞内主要元素Na+、Cl-、K+的分布情况,测定的细胞类型包括:①叶脉细胞(叶脉维管束导管、叶脉维管束内部和外部的薄壁细胞);②叶肉细胞(栅栏组织、海绵组织);③表皮细胞(上、下表皮细胞).结果表明,胡杨和毛白杨叶细胞对盐离子的区隔化有明显差异:与毛白杨相比,盐处理后的胡杨叶细胞不但具有较高的拒Na+能力,即将Na+贮存在质外体中,而且液泡区隔Na+的能力也强于毛白杨.在Cl-的区隔化方面,对照处理胡杨各种类型的细胞(包括叶脉、叶肉和表皮细胞)Cl-浓度都高于毛白杨,但在盐胁迫下,胡杨叶片的细胞壁、液泡甚至叶绿体中Cl-的含量都低于毛白杨,这是胡杨根细胞限制Cl-离子根冠运输的结果.盐处理使胡杨叶片各种类型细胞中的K+浓度降低;与胡杨不同,毛白杨叶片细胞中质外体的K+浓度下降,而液泡中的K+水平却相应提高,这是毛白杨细胞内K+重新分配的结果:由于盐处理后毛白杨液泡内积累了过多的Cl-,K+从细胞壁进入液泡,用以平衡液泡内Cl-积累所带来的负电荷.     

力克斯兔被毛生物学特性研究

力克斯兔的初级毛囊、次级毛囊于胚胎的18－24天先后出现，基皮肤表皮、真皮的发生与分化于胚胎的24天已基本完成，26胎龄时，初级毛囊结构分化完全，并可见到皮脂腺，26胎龄至仔兔出生，是表皮和毛囊分化出的各组成成分的进一步生长阶段。仔兔出生以后，皮肢表皮和毛囊的结构均无明显变化，但表皮厚度稍有增加、毛囊仍继续向真皮，只是远不及胚胎期迅速。表上的增长及毛囊的生长速度，在不同部位之间无显著差异，而不同胎龄（月龄）之间存在显著或极显著的差异。力克斯兔皮肤的毛囊群结构很有规律，每一毛囊群由2－6个扇形分布的亚毛囊群组成，每一亚毛囊群中又含有5－12个分生毛囊和衍生分生毛囊。力克斯兔出生以后，其衍生分生毛囊数的增加几科与体表面积的增大呈比例，致使各月龄之间毛囊密度无显著差异，但不同部位之间，毛囊密度差异显著。力克斯兔被毛因粗毛含量少、分布均匀、直径也小， 毛纤维短、细，且粗细毛长度一致，密度大、强度大、伸度小（与新西兰白兔比较），从而构成了力克斯兔被毛具有弹性强、柔软性好、平整、美观、经久耐磨等特征。通过扫描电镜及光学显微镜对力克斯兔、新西兰白名锿安哥拉兔三个不同类型的兔种的兔毛纤维鳞片排列形态及髓腔结构的观察，发现不同类型之间，鳞片的排列形态不同，但髓腔结构的差异不明显。     

农艺因素对杂交棉浙杂166纤维产量和品质的影响及若干生理性状的杂种优势

在三个地区进行了大田试验和盆栽试验,研究农艺因素对杂交棉浙杂166的纤维产量和品质的影响及杂交种若干生理性状的杂种优势。结果表明,最佳种植密度和氮肥用量因地区而异,金华点要比杭州和慈溪要求较低的种植密度和较高的氮肥用量;播种日期以4月15日播种地膜覆盖的处理铃数最多。从纤维产量和衣指上看,最适密度和氮肥用量分别为每公顷4.5万株和180kg,播种日期为杭州和慈溪为4月15日,金华为4月20日,播种后全部地膜覆盖。不同密度、氮肥用量及播种期之间,纤维品质无显著差异,但慈溪点表现为N1(135kg·hm 2)处理的纤维长度显著低于其它氮肥用量较多的处理。叶绿素含量(以SPAD表示)生育期间变异很大,在初花期和吐絮期,杂交种浙杂166高于其双亲和常规品种泗棉3号,而在盛花期和结铃期恰好相反。杂种及其双亲的MDA含量在生育期间也表现出较大的变化,且杂种的变化模式与不育系相似,表现为蕾期较低,而初花期及此后保持较高。与双亲相比,浙杂166具有明显的SOD杂种优势,生育期间的变化模式也与不育系相似。