紫花苜蓿甘氨酸脱羧酶H-蛋白基因MsGDC-H1功能分析

光呼吸通过清除2-磷酸乙醇酸（2-PG）使氧合光合作用成为可能,该过程对C3植物至关重要。H-蛋白是光呼吸过程中将甘氨酸转化为丝氨酸的甘氨酸脱羧酶（GDC）的关键组成蛋白之一。本研究克隆了紫花苜蓿MsGDCH1,该基因编码166个氨基酸,具有1个硫辛酰基附着位点保守结构域和1个N6-硫辛酰赖氨酸保守位点。进化分析表明,MsGDC-H1蛋白与双子叶植物的甘氨酸脱羧酶H-蛋白（GDC-H）亲缘关系近。表达模式分析表明,MsGDC-H1在苜蓿叶中表达丰度高,且受光诱导。为了探究MsGDC-H1基因对拟南芥生长的影响,分别使用光诱导的茎叶特异性启动子ST-LS1和组成型启动子CaMV 35S驱动MsGDC-H1(ST-LS1::MsGDC-H1;CaMV35S::MsGDC-H1)在拟南芥中异源表达。检测过表达植株生物量、淀粉、可溶性糖含量以及光合速率。数据分析显示,CaMV 35S::MsGDC-H1过表达拟南芥（G系列植株）生长受阻,淀粉含量比ST-LS1::MsGDC-H1特异性表达拟南芥（GS系列植株）增加了34%～67%,比野生型（WT）增加了7。3%～33。7%;可溶性糖含量比GS...     

断奶仔猪的糖类营养及主要来源

早期断奶仔猪易受生理、营养和环境的影响,而产生应激影响其正常生长,其中营养因素最为重要,本文阐明了仔猪料中碳水化合物的作用及其消化酶的分布特点,描述了仔猪对碳水化合物的消化吸收机理,并对几种主要的碳水化合物来源和利用性能进行分析和总结,为合理配制断奶仔猪饲料提供理论基础。     

Effects of dietary carbohydrate on weight gain and gonad production in small sea urchins,Lytechinus variegatus

In experiment 1, juvenile sea urchins (n = 80, 0.088 ± 0.001 g wet weight and 5.72 ± 0.04 mm diameter) were held individually and fed ad libitum one of three semi‐purified formulated diets (n = 16 individuals treatment^?1). In the diets, protein was held constant (310 g kg^?1 dry, as fed) and carbohydrate level varied (190, 260, or 380 g kg^?1 dry, as fed). Wet weights were measured every 2 weeks. Total wet weight gain was inversely proportional to dietary carbohydrate level and energy content of the respective diet. In experiment 2, sea urchins (5.60 ± 0.48 g wet weight, n = 40) fed 190 g kg^?1 carbohydrate consumed significantly more dry feed than those fed 260 g kg^?1, but not more than those fed 380 g kg^?1 carbohydrate. Based on differential feed intake rates, sea urchins that consumed more feed also consumed higher levels of protein and had the highest weight gain. Consequently, protein content and/or protein: energy ratio may be important in determining feed utilization and growth among sea urchins in this study. The average digestible energy intake was approximately 70 kcal kg^?1 body weight day^?1, suggesting daily caloric intake of juvenile Lytechinus variegatus is lower than in shrimp and fish.     

不同种类碳水化合物对吉富罗非鱼生长性能、体组成和血清生化指标的影响

为了解罗非鱼对不同种类碳水化合物(CBH)的利用效果,研究了6种碳水化合物对罗非鱼生长性能、体组成和血清生化指标的影响。实验选用720尾初重为(3.0±0.3)g的健康吉富罗非鱼,随机分为6组,每组4个重复,每个重复30尾,分别投喂设计含30%南方糙米、次粉、玉米淀粉、马铃薯淀粉、甘薯淀粉和木薯淀粉的6种不同CBH的等氮、等能饲料,实验周期为8周。结果显示,南方糙米、玉米淀粉组的终末均重、增重率、特定生长率和蛋白效率显著高于其他组,而饲料系数明显最低(P0.05)。CBH种类明显影响全鱼、肌肉的组成(P0.05)。玉米淀粉组肝糖原含量明显高于马铃薯淀粉、甘薯淀粉和木薯淀粉组(P0.05),而马铃薯淀粉和甘薯淀粉组的血糖明显低于木薯淀粉、玉米淀粉和次粉组(P0.05)。CBH种类对血清CHO、TG影响明显(P0.05),但对TP、SOD、T-AOC和MDA的影响不明显(P0.05)。研究表明,不同种类CBH对罗非鱼生长性能的影响明显(P0.05),以特定生长率为指标,罗非鱼对南方糙米和玉米淀粉的利用效果较好。     

Effect of dietary protein/carbohydrate ratio on activities of hepatic enzymes involved in the amino acid metabolism of Nile tilapia, Oreochromis niloticus (L.)

This study investigated the influence of different dietary protein/carbohydrate ratios on activities of enzymes involved in the amino acid metabolism as well as on growth performance and body composition of Nile tilapia (Oreo- chromis niloticus). Fish were fed semi-synthetic diets differing in their protein/carbohydrate ratio. The diets were formulated to be isolipidic and isoenergetic (on the basis of metabolizable energy). Fish were reared individually. After a prefeeding phase, tilapia were randomly assigned to three groups and were fed the experimental diets at a relatively low level. The study lasted 9 weeks. Proximate composition, gross energy content, and activities of aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) in the liver of fish were determined. While the mean growth rate and feed conversion efficiency did not differ significantly among the feeding groups, the body composition showed significant differences. The dietary protein/carbohydrate ratio had no significant effect on the protein and energy gain, but the lipid gain was significantly higher in tilapia fed the low-protein diet. The activities of ASAT and ALAT per gram of liver and per gram of soluble protein were significantly increased in fish fed the high-protein diet. There was a significant positive correlation between the activities of ASAT and ALAT. The activities of both enzymes in the liver were significantly higher in fish with a higher protein gain. Measuring the activities of enzymes involved in the amino acid metabolism can provide more information about the metabolic utilized dietary protein.     

饲料糖水平对点篮子鱼生长性能的影响

以鱼粉为蛋白源,糊精为糖源,配制等蛋白质(含量为35%)、等能量糖水平分别为5%,10%,15%,20%,25%,35%(标号分别为T1、T2、T3、T4、T5、T6)的6组配合饲料,对点篮子鱼(Siganus guttatus)投喂56d,研究了饲料中糖水平变化对体重为34.45±10.61 g点篮子鱼生长、体成分和生物学指标的影响。结果显示,随着饲料糖水平的增加,点篮子鱼的摄食率和生长率呈先增加后降低的趋势,特定生长率(SGR)与饲料糖水平之间适宜的二次方程:y=0.455 1+0.012 5x-0.000 3x2(R2=0.913 7),点篮子鱼饲料中糖的最适添加水平为20.83%;饲料系数(FCR)和肌肉中粗脂肪含量与饲料中糖水平变化成正相关;高糖组(T6)鱼的肝脏中粗脂肪含量显著高于低糖组(P<0.05)。综合实验结果认为:点篮子鱼饲料糖适宜添加量为15%～25%。     

饲料中非蛋白能源物质对红螯光壳螯虾幼虾生长、生理、生化指标的影响

在等蛋白质、等能量基础上,研究碳水化合物与脂类比例(CHO∶L)为10.75∶1、4.81∶1、2.66∶1、1.52∶1和0.87∶1的5组试验饲料对红螯光壳螯虾[初始体质量(1.72±0.01)g]相关生长、生理、生化指标的影响。8周试验结果表明,CHO∶L比例为2.66∶1时,红螯光壳螯虾的增重率、特定生长率和饲料利用率达到最高。高比例的CHO∶L(10.75∶1)和低比例的CHO∶L(0.87∶1)都会显著地抑制(P<0.05)红螯光壳螯虾的生长和饲料的利用。饲料脂肪水平为40～145 g/kg时,虾的脂肪酶和碱性磷酸酶活力显著升高(P<0.05),己糖激酶和丙酮酸激酶活力则呈显著降低趋势(P<0.05)。CHO∶L对虾胃蛋白酶活力影响显著(P<0.01),CHO∶L为2.66∶1和1.52∶1表现出比较高的活力,显著高于(P<0.05)其它试验组。碳水化合物为156.3～360.4 g/kg范围内,虾淀粉酶活力随饲料中碳水化合物的升高而显著升高(P<0.01)。红螯光壳螯虾增重率分别与饲料中碳水化合物和脂肪水平进行二次回归分析得出,红螯光壳螯虾对配合饲料中碳水化合物和脂肪的最适需求量分别为268.28和120.22 g/kg,相对应的CHO∶L为2.20∶1,且红螯光壳螯虾对碳水化合物的利用能力要高于对脂肪的利用。     

可发酵碳水化合物减少猪场臭气的机理和应用

可发酵碳水化合物,添加在猪日粮中到达后肠作为微生物发酵的底物,通过改变猪肠道和粪便中的微生物及其发酵过程,改变粪尿的理化特性,来减少氨的挥发以及臭气的产生.本文对臭气和除臭方法进行了简单的介绍,并综述了通过在猪日粮中添加可发酵碳水化合物来控制猪场臭气的机理和应用效果.     

齐口裂腹鱼幼鱼对蛋白质、脂肪和碳水化合物需要量研究

试验设21个日粮组, 蛋白质、脂肪、碳水化合物梯度变化范围分别在33% ~ 51%、3% ~ 18%、23% ~ 32%。在水温( 25. 25 ? 1. 91) e 条件下, 在水泥池中对平均体重为( 2. 01 ? 0. 04) g的360尾齐口裂腹鱼进行了60 d的生长试验, 研究日粮中蛋白质、脂肪和碳水化合物对齐口裂腹鱼生长、体组成和肝脏组织的影响。结果表明: 各组鱼特定生长率随着日粮蛋白质水平的增加而增加; 体蛋白含量不受日粮组成的影响, 体脂肪随着日粮脂肪水平的增加而增加, 体碳水化合物受日粮碳水化合物的影响极显著, 而不受日粮蛋白质和脂肪的影响。齐口裂腹鱼幼鱼能耐忍23% ~ 26%的碳水化合物水平, 且能利用6% ~ 12%的日粮脂肪。基于齐口裂腹鱼幼鱼对日粮碳水化合物和脂肪含量需求分别为23% ~ 26%和6% ~ 12%时, 蛋白质需求量为42% ~ 48%, 能蛋比为41. 3 kJ/g。     

几个水稻品种碳素代谢特征的比较

结合饲料稻品种选育,在不同生育期对5个水稻品种（组合）进行了光合作用、呼吸作用、茎鞘非结构碳水化合物的积累和转运以及籽粒充实特性的比较研究。结果表明,不同品种其碳素代谢特性各不相同,杂交组合威优56光合作用、呼吸作用较强,茎鞘非结构碳水化合物在孕穗期积累丰富,到成熟期残留较少,后期籽粒充实速度下降缓慢,是一个碳素代谢十分旺盛的组合。常规稻辐丰早92－124在灌浆后期仍维持较高的光合强度和较强的籽粒充实速度,且成熟期茎鞘内非结构碳水化合物残留最少,也是一个后期碳素代谢较为理想的水稻品种。