Use of biofloc technology during the pre‐maturation period of Litopenaeus vannamei males: effect of feeds with different protein levels on the spermatophore and sperm quality

The objectives of this study were: (1) Compare two systems for pre‐maturation of Litopenaeus vannamei in terms of spermatophore and sperm quality, (2) Compare the effect of feeds with different protein levels on reproductive quality of males reared in a biofloc‐dominated system. Animals (36.40 ± 3.13 g) reared under biofloc technology (BFT) were used in the 30‐day experiment, which involved four treatments: one in a clear water system (CW) and other three in a BFT system. The BFT treatments were differentiated by feed: mix of fish, squid and crab (BFT+FF) composed of 68.48% dietary protein (DP); broodstock feed (BFT+BF) composed of 52.51% DP; and juvenile feed (BFT+JF) composed of 39.91% DP. Feed in the CW was also the mix of fresh food. Spermatophore and sperm quality were analyzed at the beginning and end of the experiment. Higher normal sperm rate was recorded in the CW compared with the BFT+FF. Among the BFT treatments, the BFT+FF had the lowest normal sperm rate. Thus, the use of BFT for pre‐maturation of L. vannamei allowed the reduction in dietary protein levels from 68.48% (BFT+FF) to 39.91% (BFT+JF) and the maintenance of spermatophore and sperm quality compared to the system based on high daily exchange rate.     

无芒雀麦引种适应性的观察

无芒雀麦是多年生根茎型丛生性禾本科牧草,在青海省贵南县海拔3400m的地区引种栽培,其结果表明:播种当年出苗整齐,第二年越冬良好,越冬率为91％;第二年、第三年的鲜草产量分别为10436.61kg/hm2、14100kg/hm2,其茎叶比分别为1.4:1、2.17:1,种子产量为87k/hm2,可以在贵南县进行大面积的推广种植,在无芒雀麦的开花盛期适时利用。     

冻融条件下沙丘土壤水分物理性提升的试验研究

基于乌兰敖都试验站内土壤冻融试验,探讨不同外界条件下土壤冻融作用对土壤中水分迁移的影响。结果表明:土壤冻结作用可以增加水分的迁移量,从而提高冻融层土壤水分含量,0-30cm和100-140cm深度土壤中水分迁移受冻结作用的影响比较显著,分别迁移了87.6,210.9mm,30-60cm和60-100cm深度受到的影响较小;冻融期内,稻草覆盖减小了水分向土壤上层迁移或者向下层的入渗;初始地下水埋藏较深能导致土壤水分迁移量变大。通过探究土壤冻融对水分物理性提升的影响作用,测定其提升数量,合理利用其提升的水分,改善固沙植被区浅层土壤水分条件,有利于固沙植物的生长和其他植物物种的侵入,提高固沙植被区的物种多样性,建立持久稳定的固沙植被。     

Assessing whether dairy cow welfare is “better” in pasture-based than in confinement-based management systems

ABSTRACT

Consumers perceive pasture-based systems of milk production as natural and therefore better for cow welfare than confinement systems. However both systems are heterogeneous and continually evolving, varying from total confinement to total pasture with many hybrid intermediaries. To compare the welfare of dairy cows in these various systems, we use the three spheres framework, comprising biological functioning, natural behaviour and affective states. Considering biological functioning, pasture-based cows are less at risk of subclinical and clinical mastitis, claw lesions, lameness, metritis, early embryonic mortality, culling and mortality, but at more risk of internal parasitism, malnutrition and delayed onset of oestrous activity postpartum than confined cows. Regarding natural behaviours, pasture-based cows exhibit less agonistic behaviour, better lying behaviour, more normal oestrous behaviours and better synchronicity of behaviours than confined cows. They also have the opportunity to graze, which is one of the main features of the behavioural repertoire of dairy cows, but, they may also experience long periods away from pasture in larger herds, and severe climatic stresses which will become increasingly important as the climate changes. Our current ability to assess the affective state of dairy cows is poor. For example, hunger is an important subjective state that cannot be measured directly. The growing focus on ensuring that animals have lives worth living, means that dairy cows should garner some positive emotions from their lives, and it seems clear that pasture access is essential for this. Clearly measurement of affective state is an important challenge for future dairy cow welfare research. At the extremes of management systems, there can be major differences in animal welfare but in hybrid systems, dairy cows experience elements of both confinement and pasture which may ameliorate the negative effects of each on cow welfare. Ultimately, the optimal system gives cows an element of choice between both environments. Moreover management of the system, whether it is confinement or pastured-based, may be as important as the system of management in ensuring good dairy cow welfare and addressing societal concerns.

Abbreviations: BCS: Body condition score; TMR: Total mixed ration     

青海互助土族民间利用野生植物调查

采用民族植物学和人类学的研究方法,对青海互助土族民间利用野生植物进行了调查.结果表明,与当地土族直接相关的野生植物包括32种,经常食用的有12种.     

黄河上游高寒地区建植人工草地引种试验

对8种多年生禾本科牧草品种在黄河上游高寒草地进行人工草地引种试验.结果表明:当年均出苗且生长良好,但种子不能成熟,只能达到拔节期;第2年越冬率达90%以上,无芒雀麦Bromus inermis,垂穗披碱草Elymus mutans,多叶老芒麦E.exceisns,老芒麦E.sibiricus青干草产量均达3 000 kg/hm2以上,冷地早熟禾Poa crymphila,草地早熟禾P.pratensis青干草产量在1 500 kg/hm2左右;种子成熟好的有冷地早熟禾、多叶老芒麦、老芒麦、垂穗披碱草,说明供试的8种多年生禾本科牧草品种在青海省黄河上游海拔3 400 m左右的地区推广种植,效果良好.     

Effect of DHA Containing Oils and Powders on Baking Performance and Quality of White Pan Bread

Different sources of DHA and/or n-3 (omega-3) rich oils, oil emulsions and microencapsulated (ME) powders were tested at two different concentrations with the aim of producing fortified pan bread. Three oils (S-algae, fish and flax), two emulsified algae oils (Emulsion-P and Emulsion-L) and two ME oils (ME-S algae and ME-C algae) were compared. The DHA and n-3 oils replaced part of the shortening in order to obtain 32 g slices enriched with 25 or 50 mg DHA, 35 or 70 mg total n-3 from fish oil and 90 or 180 mg linolenic from flax oil. Addition of oils did not significantly affect water absorption but reduced mix time whereas addition of the ME oils decreased both water absorption and mix time. Breads enriched with flax or ME-C oils had lower volume and higher density than the control, ME-S algae, Emulsion-P and Emulsion-L breads. All breads lost texture throughout 14 d storage, the major changes occurred after 3 d. The ME-S algae oil bread had the best softness after 14 d storage whereas breads produced from ME-S algae or ME-C algae oils had the poorest texture. Sensory evaluations indicated that the color of the ME-S algae oil fortified bread was significantly less preferred than the other loaves. After 6 d the control bread had higher acceptability compared with the rest of the breads enriched with high levels of DHA or omega-3 oils. The high-enriched fish oil bread was well accepted during the first days of storage but had the least preferred acceptability after 13 d. The best fortified breads were those supplemented with S-algae oil, Emulsion-P and Emulsion-L oils.     

锌素营养对作物叶片解剖结构的影响

采用水培方法,调节锌素营养供应,观察芹菜、玉米、小麦幼苗生长及幼苗叶片解剖结构。结果看出,锌素营养不足时植株含匀量降低,生长受到抑制:叶肉细胞收缩,细胞间隙增大,叶肉细胞中叶绿体数量减少。禾本科作物维管柬鞘细胞中叶绿体减少尤为明显,但对叶绿体的体积无影响;辅导组织发育受到抑制,机械组织不发达。锌素营养过剩时细胞结构破坏,叶肉细胞严重收缩,叶绿体明显减少。