低蛋白日粮补充天冬氨酸对断奶至育肥阶段猪生长性能及肉品质性状的影响

旨在研究低蛋白日粮补充天冬氨酸对断奶至育肥阶段猪生长性能、血液生化指标和游离氨基酸、养分表观消化率以及肉品质性状的影响。选取20头45日龄,体重相近（（10.93±0.79） kg）的健康三元杂交（杜×长×大）断奶仔猪,随机分成两组,每组10个重复,每个重复1头猪,仔猪单栏饲养,试验期84 d。对照组饲喂玉米-豆粕型低蛋白基础日粮,试验组饲喂在基础日粮中添加0.5%天冬氨酸的试验饲粮。结果表明：1）添加天冬氨酸可显著提高猪断奶阶段平均日增重（P<0.05）并极显著降低料重比（P<0.01）,但在育肥和生长阶段对生长性能无显著影响（P>0.05）;2）添加天冬氨酸可显著提高断奶阶段血清白蛋白水平和碱性磷酸酶活性（P<0.05）,但对生长和育肥阶段血液生化指标均无显著影响（P>0.05）;3）添加天冬氨酸可显著降低断奶阶段血清中Pro、Met、Thr、Asp、His、Tyr含量（P<0.05）和提高Lys水平（P<0.01）,生长阶段血清中Asp、Lys含量和育肥阶段Asp、Thr含量显著降低（P<0.05）,对其他氨基酸含量无显著影响（P>0.05）;4）天冬氨酸处理可使育肥猪总能、粗蛋白、粗脂肪、粗灰分、粗纤维表观消化率极显著升高（P<0.01）;5）天冬氨酸处理可有效提高熟肉率（P<0.01）和背最长肌中MyHC1的mRNA表达水平（P<0.05）。综上可知,低蛋白日粮全程添加0.5%天冬氨酸可有效提高猪断奶阶段的生长性能,有利于促进其后期肌纤维的发育和改善其肉品质性状。     

Growth and hepatopancreas performances of gibel carp fed diets containing low levels of aflatoxin B1

The effects of aflatoxin B₁ (AFB₁) on growth, physiological responses and histological changes were investigated in juvenile gibel carp (Carassius auratus gibelio). Triplicate groups of gibel carp (3.53 ± 0.02 g) were fed seven semipurified diets (Diet 1 to 7) containing 3.20, 5.37, 7.08, 9.55, 12.70, 17.90 and 28.60 μg AFB₁ kg^?1 diet for 3 months. The results showed fish weight gain fed Diet 6 was 112.6% of that of control group (Diet 1) after 3 months, but there was no significant difference of weight gain between fish fed Diet 7 and the control group. Alanine aminotransferase (ALT) of fish hepatopancreas fed Diet 7 was significantly higher than the control group (P < 0.05), but no significant difference was observed in ALT activities of the fish fed with more than 10 μg AFB₁ kg^?1 (Diet 4, 5, 6 and 7). No significant histological lesions were identified between the control and increasing AFB₁ treatments. AFB₁ accumulated in hepatopancreas was logarithmically related to the dietary AFB₁ levels, and AFB₁ also accumulated in muscles and ovaries of gibel carp fed Diet 3 to Diet 7. The present results indicated that fish fed with more than 10 μg AFB₁ kg^?1 diet showed impaired physiological responses and more AFB₁ residue of muscles and ovaries above the safety limitation of European Union.     

氧化鱼油对草鱼幼鱼磷酸酶和转氨酶活性的影响

为研究不同程度的氧化鱼油对草鱼幼鱼体内2种磷酸酶及2种转氨酶活性的影响。选取平均初始体质量为(30.0±2.6)g的健康草鱼幼鱼204尾,随机分成4组,每组3次重复。在草鱼幼鱼饲料中分别添加不同鱼油,分别为对照组(新鲜鱼油,过氧化值4.54 mmol/kg)及鱼油氧化程度逐渐加深的3个氧化鱼油组(OX1过氧化值24.86 mmol/kg,OX2过氧化值72.32 mmol/kg,OX3过氧化值172.73 mmol/kg)。试验58 d后取样,分别测定草鱼幼鱼血清、肝胰脏、脾脏、肾脏等组织中碱性磷酸酶(AKP)、酸性磷酸酶(ACP)、谷草转氨酶(AST)及谷丙转氨酶(ALT)活性,并计算血清和肝胰脏AST/ALT值。结果表明:与对照组相比,3个氧化鱼油组肝胰脏和脾脏中AKP活性显著升高(P0.05),OX3组血清及OX1、OX2组肠道中AKP活性显著升高(P0.05);OX2组肝胰脏和脾脏中ACP活性显著升高(P0.05)。与对照组相比,OX3组血清、OX2组肝胰脏及OX2、OX3组肠道中AST活性显著升高(P0.05),而OX3组肾脏中AST活性显著降低(P0.05);OX1、OX2组背肌及OX2、OX3组肠道中ALT活性显著升高(P0.05);OX3组血清和肝胰脏中AST/ALT值显著升高(P0.05)。综上所述,氧化鱼油对草鱼幼鱼血清及不同组织中的AKP、ACP、AST及ALT活性变化存在较大差异;同时随着鱼油氧化程度加深,草鱼幼鱼各组织细胞受损,免疫功能降低。     

青翅蚁形隐翅虫毒素粗提物对菜青虫3种酶活性的影响

[目的]研究青翅蚁形隐翅虫毒素的杀虫机制,为研制开发该杀虫剂提供理论依据。[方法]采用青翅蚁形隐翅虫毒素粗提物饲喂和点滴菜青虫,测定和分析了虫体组织中肠酯酶、谷-丙转氨酶、乙酰胆碱酯酶和乙酰胆碱的变化情况。[结果]饲喂夹毒叶片的3龄菜青虫在48h后中肠酯酶含量下降明显,酶活性略受抑制。经毒素点滴处理的3龄菜青虫谷-丙转氨酶含量24、48h后均降低,24、48h后酶比活力均呈现增强趋势;经毒素粗提物处理的菜青虫24、48h后乙酰胆碱酯酶含量变化不大,但均有明显的降低,酶比活力增强。毒素粗提物对乙酰胆碱有抑制作用。[结论]青翅蚁形隐翅虫毒素粗提物对菜青虫幼虫具有较好的抑制作用。     

不同光周期对高粱叶片和蚜虫体内营养物质含量和相关酶活性的影响

为明确光周期对高粱和高粱蚜体内物质含量的影响,该研究设置了5个光周期,分别为2L∶22D、6L∶18D、10L∶14D、14L∶10D、18L∶6D,测定不同光周期下高粱叶内可溶性蛋白、可溶性糖、游离氨基酸、淀粉和叶绿素含量,同时检测了高粱蚜体内的谷草转氨酶(aspartate aminotransferase,AST)、谷丙转氨酶(alanine transaminase,ALT)、超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)的活性,以及可溶性蛋白、可溶性糖、游离氨基酸、总脂肪的含量。结果表明:在长光照(10L∶14D、14L∶10D、18L∶6D)下,高粱叶片的可溶性糖、游离氨基酸、淀粉和叶绿素含量高于短光照(2L∶22D、6L∶18D),极短光照(2L∶22D)和最适光照(14L∶10D)条件下高粱叶片的可溶性蛋白含量低于其他光周期;在极长光周期(18L∶6D)条件下,高粱蚜体内的ALT和AST活性最高,光周期为10L∶14D时高粱蚜体内ALT和AST活性均达最低值;短光照(2L∶22D、6L∶18D)条件下高粱蚜体内保护酶SOD和CAT活性高于长光照(10L∶14D、14L∶10D、18L∶6D)条件;在光周期为10L∶14D时高粱蚜体内可溶性蛋白、可溶性糖和总脂肪含量达最高值,光周期为14L∶10D时高粱蚜的游离氨基酸含量最低。说明在极端光周期时,为了应对不良环境高粱蚜体内转氨酶活性呈上升趋势,保护酶活性在短光照条件下升高;10L∶14D的光周期适合高粱蚜生长发育,高粱蚜体内营养物质含量较高;极端光周期条件下高粱蚜的可溶性蛋白、可溶性糖、总脂肪含量呈下降趋势。     

Activities of Enzymes in the Malate–Aspartate Shuttle in the Peripheral Leukocytes of Dogs and Cats

The activities of the enzymes involved in the malate–aspartate shuttle and the expression of malate dehydrogenase (MDH), a rate-limiting enzyme in the NADH shuttle that produces ATP in glucose metabolism in leukocytes, were determined to investigate the differences in this shuttle system in the peripheral leukocytes of dogs and cats. There were no significant differences between dogs and cats in plasma glucose, immunoreactive insulin, free fatty acid or triglyceride concentrations. The activities of cytosolic and mitochondrial MDH and of mitochondrial glutamate dehydrogenase (GLDH) in canine leukocytes were significantly higher than in feline leukocytes. High activities of MDH in canine leukocytes were confirmed by RT-PCR analysis on the total RNA extracted from leukocytes. It was concluded that there were significant differences between dogs and cats in the NADH shuttle system.