大小麦附加系的细胞学稳定性观察

对１Ａ，２Ａ，３Ａ，４Ａ，６Ａ及７Ａ等６个大小麦附加系的细胞学稳定性进行了观察。发现经两代繁殖后，其种子根尖细胞染色体有丢失现象。在减数分裂过程中，均观察到单价体、多价体、染色体断片、后期染色体落后、染色体桥及四分体微核等异常现象；经对四分体微核出现频率的统计，表明４Ａ，６Ａ及７Ａ等３个附加系在细胞学上相对较不稳定。     

添加葡萄糖对绿狐尾藻与麦麸混合青贮品质的影响

以鲜质量比7∶3的绿狐尾藻和麦麸为原料混合青贮,分别添加0%、2%、4%、6%的葡萄糖,固定添加植物乳杆菌,测定混合青贮饲料的发酵品质、营养品质及有氧稳定性。结果表明：添加葡萄糖能显著(P<0.05)降低混合青贮饲料的pH值和氨态氮与总氮质量分数之比,显著(P<0.05)提高乳酸质量分数,降低丁酸质量分数,改善青贮发酵品质;显著(P<0.05)降低粗蛋白和粗纤维质量分数,且显著(P<0.05)提高相对饲用价值;当葡萄糖添加量为4%时显著(P<0.05)降低中性洗涤纤维和酸性洗涤纤维质量分数;添加0%、2%、4%、6%葡萄糖处理的有氧稳定性分别为>360、226、>360、62 h。综合评价结果显示,鲜质量比7∶3的绿狐尾藻和麦麸混合青贮中添加2%葡萄糖,混合青贮有更好的发酵品质和营养品质及有氧稳定性。     

基于基因编辑技术创制高亚油酸水稻材料

【目的】亚油酸是一种人体必需的脂肪酸,能加快体内脂肪代谢与分解、减少胆固醇在血管壁上形成积存、有效预防动脉硬化的发生、提高人体免疫力、促进骨骼发育、提高记忆力、预防脑部功能退化等功能。利用基因编辑技术对控制脂肪酸合成途径的关键酶ω-3脂肪酸去饱和酶基因进行精准编辑,关闭下游产物的合成途径,以便提高水稻上游亚油酸的含量,为创制富集亚油酸水稻材料提供依据。【方法】水稻脂肪酸合成途径中的关键酶ω-3脂肪酸去饱和酶基因（OsFAD3）存在2个拷贝,分别分布在第11和第12染色体,且两者cDNA同源性达97.32%。根据基因编辑原理（编辑的特异性取决于引导RNA（gRNA）的特性）,在2个同源基因序列高度一致的外显子区域,分别设计合成2个gRNA,并分别构建植物基因编辑载体,利用农杆菌介导法转化本地受体材料（富源4号）。通过对基因编辑植株进行靶位点测序鉴定,分析2个位点的编辑效率和基因型。同时,对OsFAD3双突变体进行粒宽、粒长等主要籽粒农艺性状分析。采用气质联用检测法测量OsFAD3双突变体籽粒的37种脂肪酸含量。【结果】获得2个位点的纯合编辑材料,同时也获得了其他不同基因型组合的编辑材料;与对照材料相比,OsFAD3双突变体的粒宽、粒长等主要籽粒农艺性状均没有发生显著变化,但稻谷中亚油酸的相对含量提高了3.36个百分点。【结论】在不改变籽粒主要农艺性状的前提下,实现了利用基因编辑技术通过转化一个载体同时精准敲除2个ω-3脂肪酸去饱和酶基因,提高了籽粒中亚油酸的相对含量。     

NaOH预处理对青稞秸秆厌氧发酵特性的影响

为提高青稞秸秆的综合利用率,采用NaOH对青稞秸秆进行预处理,研究不同水平NaOH和预处理时间对青稞秸秆厌氧发酵性能的影响,探讨NaOH在青稞秸秆厌氧发酵中应用的可行性。结果表明,与未经处理的青稞秸秆相比,NaOH预处理可以显著提高青稞秸秆产甲烷性能（P<0.05）,且产气速率快、发酵周期短。其中,5% NaOH处理12 h青稞秸秆的累积甲烷产量高于多数木质纤维素类废弃物,为250.03 mL·g^-1,是优良的发酵原料。NaOH预处理增加了青稞秸秆中纤维素含量（13.37%~39.31%）,并有效降解了木质素（12.89%~64.34%）和半纤维素（0.96%~30.30%）含量。表明NaOH预处理是提高青稞秸秆厌氧发酵产甲烷性能的有效方法。     

Effect of feeding acidified or fermented barley using Limosilactobacillus reuteri with or without supplemental phytase on diet nutrient digestibility in growing pigs

Fermentation of cereal grains may degrade myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate) (InsP₆) thereby increasing nutrient digestibility. Effects of chemical acidification or fermentation with Limosilactobacillus (L.) reuteri with or without phytase of high β-glucan hull-less barley grain on apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients and gross energy (GE), standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AAs), and standardized total tract digestibility (STTD) of P were assessed in growing pigs. Pigs were fed four mash barley-based diets balanced for water content: 1) unfermented barley (Control); 2) chemically acidified barley (ACD) with lactic acid and acidic acid (0.019 L/kg barley grain at a ratio of 4:1 [vol/vol]); 3) barley fermented with L. reuteri TMW 1.656 (Fermented without phytase); and 4) barley fermented with L. reuteri TMW 1.656 and phytase (Fermented with phytase; 500 FYT/kg barley grain). The acidification and fermentation treatments occurred for 24 h at 37 °C in a water bath. The four diets were fed to eight ileal-cannulated barrows (initial body weight [BW], 17.4 kg) for four 11-d periods in a double 4 × 4 Latin square. Barley grain InsP₆ content of Control, ACD, Fermented without phytase, or Fermented with phytase was 1.12%, 0.59%, 0.52% dry matter (DM), or not detectable, respectively. Diet ATTD of DM, CP, Ca, and GE, digestible energy (DE), predicted net energy (NE) value, and urinary excretion of P were greater (P < 0.05) for ACD than Control. Diet ATTD of DM, CP, Ca, GE, DE and predicted NE value, urinary excretion of P was greater (P < 0.05), and diet AID of Ca and ATTD and STTD of P tended to be greater (P < 0.10) for Fermented without phytase than Control. Diet ATTD of GE was lower (P < 0.05) and diet ATTD and STTD of P, AID and ATTD of Ca was greater (P < 0.05) for Fermented with phytase than Fermented without phytase. Acidification or fermentation with/without phytase did not affect diet SID of CP and AA. In conclusion, ACD or Fermented without phytase partially degraded InsP₆ in barley grain and increased diet ATTD of DM, CP, and GE, but not SID of CP and most AA in growing pigs. Fermentation with phytase entirely degraded InsP₆ in barley grain and maximized P and Ca digestibility, thereby reducing the need to provide inorganic dietary P to meet P requirements of growing pigs.     

热稳定脱脂米糠蛋白质碳水化合物酶-蛋白酶分步提取法酶的筛选和条件优化

热稳定脱脂米糠(HDRB)中蛋白质已严重变性,采用常规方法很难提取其中蛋白质。本研究其目的在于评价不同碳水化合物酶和蛋白质水解酶组合在HDRB蛋白质提取的作用,以及利用响应曲面方法优化蛋白质提取组合条件。结果发现使用果胶酶P-Ⅱ处理HDRB,继后对其残渣进行蛋白酶P处理,蛋白质提取率可达到80%。采用中心成分回归设计进一步对果胶酶P-Ⅱ、蛋白酶P、水糠比、温度、pH、提取时间进行RSM优化,最大蛋白质提取率可达到89%。本研究为合理利用米糠蛋白及利用米糠蛋白制备功能性短肽提供了可靠的方法。     

Effects of partial and complete replacement of freshwater shrimp meal (Caridinea niloticus Roux) with a mixture of plant protein sources on growth performance of Nile tilapia (Oreochromis niloticus L.) in fertilized ponds

Despite the well‐documented herbivorous food habits, commercial feeds for production of Oreochromis niloticus usually contain between 7% and 15% animal protein. However, animal protein feedstuffs are expensive, hence the need to search for cost‐effective alternatives in plant‐protein sources. Such alternatives are probably more effective in semi‐intensive systems where natural pond food forms part of the diet. This study evaluated the performance of O. niloticus after feeding diets in which fresh shrimp meal (SM) was gradually replaced by a mixture of plant‐protein sources in fertilized ponds. Three isonitronegenous (24% crude protein) diets containing 12 (control), 6% and 0% SM were fed to three groups of O. niloticus in four replicates per group for 250 days. Fish were fed daily at 2% body weight and sampled monthly to monitor growth and make feed adjustments. Growth, yields, survival and feed conversion ratio were not significantly different (P>0.05) among treatments. Growth of males was double that of females, while the sex ratio was skewed towards females. Although complete substitution of SM by plant protein did not affect the growth of tilapia, production cost was reduced by 36%. In conclusion, animal protein is not required in diets for production of O. niloticus in fertilized ponds.     

Potential longevity (Ki) of malting barley (Hordeum vulgare L.) grain lots relates to their degree of pre-germination assessed through different industrial quality parameters

Barley (Hordeum vulgare L.) grain germination is required to perform the malting process. Maintenance of barley seed viability during storage is crucial for the malt industry; and modern cultivars are bred for rapid grain dormancy release after physiological maturity. Low dormancy level combined with rain close to harvest induces pre-germination/pre-harvest sprouting damage. Pre-germination might not affect viability in the short term after harvest, but it could reduce potential longevity (K_i) of a barley seed lot. K_i value is inherent for each barley lot; however, its determination is time-consuming which precludes its assessment at an industrial scale. In this study we sought quantitative relationships between K_i and the pre-germination degree of barley grain lots, assessed through quality tests routinely performed by malthouses [Falling Number (FN), α-Amylase Activity and Carlsberg]. Field pre-germinated lots from one old barley cultivar (Quilmes Palomar) and artificially pre-germinated lots from major varieties currently grown in Argentina were used. Associations between K_i and values obtained from all quality tests analysed were found for Q. Palomar. However, FN was the parameter that yielded the best and simplest explanation of K_i variability. A significant positive linear K_i -FN relationship was also obtained for each modern barley cultivar.     

青稞Hva1基因的表达模式及表达载体的构建

为了解青稞种子胚胎成熟晚期丰富蛋白(LEA)基因Hva1与青稞抗旱性的关系,以抗旱性强的旱地紫青稞和抗旱性弱的大麻青稞为材料,研究了不同浓度PEG胁迫下Hva1基因在两个青稞品种中的表达模式。结果表明,Hva1基因在抗旱性不同的两个青稞品种中的表达均呈单峰模式,且抗旱性强的旱地紫青稞表达峰值和对应的PEG胁迫浓度均高于抗旱性弱的大麻青稞;PEG胁迫浓度大于13.18%时,旱地紫青稞的Hva1基因表达量高于大麻青稞。可见,Hva1基因的表达在青稞的抗旱中起到重要的作用,为此我们成功构建了青稞Hva1基因的过量表达载体,期望为抗逆性基因在青稞中的应用和抗旱新品种的选育奠定基础。     

谷特菌对青稞生长及土壤生态效应的影响

为了解生物肥对西藏青稞生长的影响,开展了谷特菌不同施用时期(播前、青稞拔节期),不同施用量对青稞产量影响的试验,供试生物肥为谷特菌,供试青稞品种为春青稞藏青320。在青稞收获期采样分析了青稞生物产量和经济产量,同时采集土样分析了土壤蔗糖酶、微生物量N等指标。结果表明:(1)施用谷特菌促进青稞分蘖,增加成穗数,在拔节期施用还能提高青稞灌浆能力,增加青稞穗粒数,提高青稞产量;(2)施用谷特菌对土壤0~10 cm土层蔗糖酶活性影响大,表现为土壤蔗糖酶活性随谷特菌施用量增加而增强,当施用量相同时,拔节期施用谷特菌导致土壤蔗糖酶活性增强,但对土壤微生物量N影响无统一规律。