高赖氨酸玉米主要品质性状的配合力分析

用4个软质胚乳和4个硬质（或半硬质）胚乳的高赖氨酸玉米自交系，进行8×8完全双列杂交试验，分析了后代籽粒品质性状的遗传表现和配合力。软质胚乳亲本和硬质胚乳亲本杂交时，当代F1籽粒的胚乳硬质度表现出显著的正反交差异，以硬质亲本作母本时F1籽粒硬质度较高，但F2籽粒的硬质度无显著的正反交差异。硬×硬类型杂交后代的     

Dietary selection for lysine by piglets at differing feeding regimen

The aim of the present study was to investigate preferences of piglets for diets varying in lysine (Lys) concentration and whether those preferences are influenced by changing position of diets on offer in feeders. For this purpose, a feeding trial was carried out over a period of 5 weeks. Piglets (equal proportions of barrows and gilts) with an initial BW of 7.4 ± 0.9 kg were randomly subdivided into four groups of 12 pigs each and were housed in single pens. Two reference groups were fed diets containing either 0.7% Lys (low-Lys group) or 1.0% Lys (high-Lys group). Two other groups had the choice from two diets containing 0.7 or 1.0% Lys offered simultaneously in identical feeders. For animals of one of these choice groups (Lys-choice 1 group) the position of diets in the feeders remained unchanged throughout the experimental period, but for animals of a second choice group (Lys-choice 2 group) position of the diets on offer in the feeders was changed two times a week.Average daily feed intake and daily gain were greatly (p < 0.05) decreased in animals of the low-Lys group compared to other treatments, and feed to gain ratio was increased. Performance of animals in Lys-choice 1 group was numerically decreased compared to animals of Lys-choice 2 group. Chosen diets of Lys-choice groups 1 and 2 contained on average 31 and 19% feed with 0.7% Lys, respectively. Resulting Lys contents of total diets were 0.94 and 0.98% for Lys-choice groups 1 and 2, respectively, as a mean of the experiment. In week 1 animals of both Lys-choice groups met approximately 50% of total feed intake by consumption of the 0.7% Lys diet. Animals of Lys-choice 1 group lowered this portion to 20% in the last experimental week and animals of Lys-choice group 2 to 11%. Preference for the 1.0% Lys diet was evident (p < 0.05) from week 3 to 5 in Lys-choice 1 group and from week 2 to 5 in Lys-choice 2 group.Piglets are able to distinguish between diets differing in Lys content and to prefer a better balanced diet over a Lys-deficient one. Changing the position of the diets on offer in the feeders two times a week does not impair the ability to select for a diet more adequate in Lys concentration, but led in contrary to a slightly higher preference for Lys.     

保护性蛋氨酸与赖氨酸在奶牛生产中的应用

乳蛋白是体现牛奶质量的重要指标,乳蛋白氨基酸来源于日粮氨基酸。乳蛋白中酪蛋白、乳白蛋白和乳球蛋白除了满足人体基本营养需求,还对人体生长、发育和健康发挥重要作用,是动物源优质蛋白质来源。蛋氨酸与赖氨酸是奶牛日粮限制性氨基酸,不仅是乳蛋白合成的重要底物,同时还作为信号分子调控乳蛋白基因表达。本文综述了奶牛氨基酸需要与来源、必需氨基酸、限制性氨基酸、保护性蛋氨酸和赖氨酸在日粮中的应用,阐述了氨基酸营养在蛋白质合成代谢中的核心作用,为指导奶牛日粮配方提供参考。     

不同赖氨酸添加水平对雏鸡前期体重发育的影响

[目的]了解商品性基础日粮赖氨酸含量是否适宜。[方法]将300只7日龄广西黄肉种鸡雏鸡随机分为5组,在基础日粮中另外添加不同含量的赖氨酸,以基础日粮为对照组进行为期20 d的饲喂试验。分阶段统计不同含量赖氨酸对增重情况的影响。[结果]添加0.15%赖氨酸的雏鸡在17日龄和27日龄的体重最大;27日龄时添加0.10%和0.25%赖氨酸组的体重最小。[结论]在商品性基础日粮中添加赖氨酸对雏鸡早期增重有影响。     

黄瓜发芽期耐冷性与赖氨酸脱羧酶基因表达

 经15℃低温诱导，采用cDNA-AFLP技术从耐冷性强的黄瓜品种长春密刺中分离到一条特异片段，该片段在耐冷性弱的北京截头中不能被诱导，命名为cctr132。将cctr132回收测序并翻译为氨基酸序列，用blastx和blsatp程序在NCBI GenBank数据库中进行同源性检索和相似性比对，结果发现cctr132与水稻推测的类赖氨酸脱羧酶蛋白同源性为88.37%，相似性为100%，并且在CCTR132中检测到了赖氨酸脱羧酶家族推测的保守结构域PGGXGTXXE，说明黄瓜发芽期耐冷性与赖氨酸脱羧酶基因表达有关。     

Chilling Tolerance of Cucumber During Germination is Related to Expression of Lysine Decarboxylase Gene

Using cDNA-AFLP technique, a specific fragment was isolated from cucumber cultivar Changchun mici possessing chilling tolerance induced at low temperature （15℃）. This fragment, named cctr 132, could not be induced in the chilling sensitive cucumber cultivar Beijing jietou. After recovering the fragment, sequencing and translating, the results of blastx and blastp in GenBank of NCBI indicated that CCTR132 had 88.37% identities and 100% positives with Oryza sativa putative lysine decarboxylase-like protein respectively, and PGGXGTXXE, the putative conserved domain of lysine decarboxylase family, was detected from CCTR132, suggesting the cucumber chilling tolerance during germination is related to the expression of the lysine decarboxylase gene.     

棉仁(籽)饼—玉米型肉仔鸡饲粮的研究

用LOHMANN品种肉仔鸡608只进行两次试验,研究了棉仁(籽)饼—玉米型饲粮的应用问题,单因子设计。第一次试验给饲八种试粮:(1)、棉仁饼(CSM)为0,游离棉酚(FG)为0;(2)、CSM为7.5%,FG为111ppm;(3)、(2)+亚铁离子(Fe~(++))111ppm;(4)、CSM为15.0%,FG222ppm;(5)、(4)+F~(++)222ppm;(6)CSM为30％,FG为444ppm;(7)、(6)+Fe(++)444ppm;(8)、(6)+L—赖氨酸(Lys)。第二次试验给饲4种试粮:(9).CSM:大豆饼(SBM)=20:80,粉料;(10).CSM:SBM=50:50,粉料;(11).CBM:SBM=100:0,粉料;(12)、(11),颗粒料。结果:(1)、CSM配比为0—7.5—15.0—30.0%,FG为0—111—222—444ppm时,不经任何脱毒处理,各组49日龄增重(分别为1779.3—1853.8—1861.3—1819.0克)、累积耗料(分别为3978—4217—4208—4158克)、耗料比(分别为2.24—2.27—2.26—2.29)等均未随FG水平提高而产生有规律的明显差异;鸡肝脏残留FG均在安全水平以下;氰化高铁血红蛋白(CNMHb)在正常生理范围以内。(2)、日粮FG为111—222—444ppm时,分别添加111—222—444ppm的Fe~(++)后,对试粮各项生产指标、能量代谢率、蛋白质表现存留率、鸡肝脏残留FG水平、血液CNMHb量均未发生明显影响。(3)、当CSM:SBM分别为20:80、50:50、100:0,构成等蛋白质(%),不等能量浓度(不以饲料脂肪调整)的试粮,试鸡各项生产指标差异均不显著(P>0.05)。(4)、CSM配比为30%时,添加L—Lys,将Lys:精氨酸(Arg.)由1:1.6～1.7调整为1:1.2。结果,Lys:Arg.平衡组(为1:1.2时)试鸡49日龄体重明显较高,但累积耗料量、耗料比,试粮能量代谢率、蛋白质表观存留率差异均不显著(P>0.05)。(5)、用棉仁饼100%地取代豆饼的低能量浓度试粮,经颗粒加工后,其饲料进食量,增重量明显提高。     

玉米杂交种间蛋白质、脂肪、赖氨酸含量变异分析

根据对229个玉米杂交种的品质分析资料,研究了蛋白质、脂肪、赖氨酸含量的品种间差异和地区间差异。     

Improving the protein content and composition of cereal grain

Cereals are important sources of protein for human nutrition but have low quality due to limitations in the amounts of essential amino acids, notably lysine. These deficiencies result from the low levels of these amino acids in the prolamin storage proteins and hence are exacerbated when high levels of nitrogen fertiliser are used to increase yield and total protein content.Genetic and genetic engineering strategies to increase both total protein content and the composition of essential amino acids have been employed. These include the exploitation of mutant high lysine genes and the use of transformation to either express additional proteins which are rich in lysine and/or methionine or to increase the free pools of these amino acids.     

赖氨酸和蛋氨酸对商品肉鸡饲养效果的研究

研究了赖氨酸和蛋氨酸对商品肉鸡的饲养效益,结果表明:前期(0—4周龄)饲粮含代谢能3,100千卡和粗蛋白质19%,补添赖氨酸0.20%和蛋氨酸0.15%;后期(5—7周龄)饲粮合代谢能3,200千卡和粗蛋白质17%,补添赖氨酸0.15%和蛋氨酸0.12%,商品肉鸡七周龄体重可达1,816±241克,料肉比2.12:1,较之按标准饲粮饲喂的对照组鸡增重提高11.11%(P<0.01),饲料消耗减少11.30%,增重饲料成本则降低2.5%。饲粮代谢能和粗蛋白质无论含量过高或过低,补添赖氨酸和蛋氨酸均未显示明显效益。此外,补添赖氨酸和蛋氨酸对提高胴体可食肉比例可能有一定作用,但对肉组分无明显影响。