安普霉素对仔猪内分泌的调控作用及血液生化指示的影响

采用单因子试验设计 ,28日龄大长北三元杂交断奶仔猪72头随机分为3组 ,研究饲料中添加不同剂量的安普霉素 (0、20、90mg/kg)对仔猪内分泌的调控作用及血液生化指标的影响。试验期为4周。结果表明 :仔猪日粮中添加90mg/kg的安普霉素可促进机体与生长有关的内分泌活动 ,提高内源激素 (生长激素、胰岛素、甲状腺激素T3)水平 (P<0.05),从而促进肌肉蛋白沉积 ;并具有显著降低血液中氨、尿素氮含量和提高血糖水平的作用 (P<0.05) ,表明安普霉素对仔猪具有增加氮沉积 ,促进蛋白质合成、抑制蛋白质分解的作用     

Inherited hyperchylomicro-naemia in the cat: Lipoprotein lipase function and gene structure

Hyperchylomicronaemia was identified in a four-week-old Siamese kitten with lethargy, in-appetence, hindlimb ataxia and profound anaemia. The kitten was euthanased and at necropsy a thrombus was found occluding the caudal aorta. Two littermates later presented with lethargy, inappetence and hypertriglyceri-daemia which resolved after being weaned on to a low fat diet. A similar condition was subsequently diagnosed in a kitten born to the same sire but a different queen. The expression of hyperchylomicronaemia in two related litters was suggestive of an inherited, familial defect in the function of lipoprotein lipase (LPL). The activity of this enzyme was reduced in all three parents, the two recovered cases and two related, but apparently unaffected kittens, compared with a control group of unrelated cats belonging to the breeder. This reduction in activity was not attributable to defective activation of LPL by its serum cofactor apolipoprotein C-II or the presence in plasma of a factor that inhibited LPL. The gene that codes for LPL was examined by restriction fragment length polymorphism analysis using a human LPL cDNA probe. The results showed that the cat has a similar, but not identical, LPL gene to man. However, there were no differences in the restriction fragment patterns obtained from affected, unaffected and control animals.     

Effect of prostaglandin F2 alpha on adrenal-produced steroid hormones in cows

Ovariectomized, nonlactating cows were treated with IM injections of either physiologic saline solution or prostaglandin F2 alpha. Plasma concentrations of cortisol increased significantly by 30 to 60 minutes after injection of prostaglandin F2 alpha, but there were no significant increases in plasma concentrations of estradiol, progesterone, or testosterone. After saline solution treatment, there were no increases in any of the hormones measured.     

Selective measurement of lipoprotein lipase and hepatic triglyceride lipase in heparinized plasma from horses.

Affinity chromatography on heparin sepharose was used to identify 2 lipolytic enzymes in heparinized plasma from horses. One enzyme was typical of hepatic triglyceride lipase (HTGL), because it was resistant to inactivation by high concentrations of NaCl, and it did not require the addition of serum for activity. The other enzyme was identified as lipoprotein lipase (LPL), because of its inactivation at NaCl concentrations in excess of 0.2M, and its dependency on addition of serum as a source of apolipoprotein C-II activator. The enzymes were purified by 347-(HTGL) and 442- (LPL) fold, with yields of 54 and 58%, respectively. The partially purified enzymes were used to design incubation conditions that gave optimal activities for each enzyme in vitro. A selective assay was then developed for direct measurement of LPL and HTGL activities in heparinized plasma from horses. Analysis of HTGL took advantage of the almost complete inactivation of LPL when serum cofactor was excluded from the assay at the NaCl concentration that gave optimal HTGL activity. Prior incubation of heparinized plasma with sodium dodecyl sulfate to inhibit HTGL was necessary for measurement of LPL, because HTGL retained 67% of its activity at the NaCl concentration required for optimal LPL activity. Activity of each enzyme was measured in heparinized plasma from 12 Shetland ponies. The mean activity +/- SD for LPL was 3.22 +/- 1.04 mumol of fatty acids/ml of heparinized plasma/h (mumol of FA/ml/h. The mean activity for HTGL was 4.9 +/- 1.56 mumol of FA/ml/h. The performance of the assay was assessed by replicate analysis of pools of each enzyme with high and low activities.(ABSTRACT TRUNCATED AT 250 WORDS)     

Plasma cholesterol and lipoprotein concentrations in the dog: The effects of age, breed, gender and endocrine disease

A combined ultracentrifugation and precipitation technique was used to quantify the plasma lipoprotein concentrations of control dogs (n=33) and dogs with diabetes mellitus (n=11), hyper-adrenocorticism (n=14), hypothyroidism (n=10) and obesity (n=20). In addition, the effect of breed type, age and gender on the lipoprotein phenotype was assessed. Breed type and age were found to have no effect upon cholesterol and lipoprotein concentrations but the high density lipoprotein cholesterol (HDL-C) concentration was greater in intact females than intact males. Cholesterol concentrations were significantly higher than those of the control group in dogs with diabetes mellitus (P<0·01), hyper-adrenocorticism (P<0·01) and hypothyroidism (P<0·001). In dogs with diabetes mellitus this was due to increased concentrations of very low density lipoprotein cholesterol (VLDL-C) (P<0·01) and HDL-C (P<0·05). The concentrations of low density lipoprotein cholesterol (LDL-C) (P<0·05) were significantly increased in dogs with hyperadrenocorticism, while in the hypothyroid dogs, VLDL-C (P<0·05), LDL-C (P<0·001) and HDL-C (P<0·05) were significantly higher than the control group. The cholesterol and lipoprotein concentrations in the obese population were not significantly different from control dogs.     

金霉素与赖氨酸和蛋氨酸交互作用研究

采用3×2×2因子饲养试验和2×2×2因子代谢试验,研究金霉素与赖氨酸和蛋氨酸的交互作用对肉仔鸡生产性能的影响,及金霉素对两种氨基酸代谢的影响。金霉素在饲料中添加150 mg/kg时,对0-3周肉仔鸡具有显著的促生长作用（P<0.01）;并显著提高肉仔鸡的饲料采食量和饲料转化率（P<0.01）,促进氮沉积（P<0.01）。对4-6周肉仔鸡的生产性能无显著影响（P>0.05）;金霉素、赖氨酸和蛋氨酸存在显著的互作关系（P<0.05）。金霉素的促生长效果受饲料中赖氨酸和蛋氨酸含量的影响,当日粮中赖氨酸水平为1.3％,蛋氨酸水平为0.6％时,肉仔鸡的生长性能最高。金霉素对赖氨酸的利用率没有显著影响（P>0.05）,对蛋氨酸和胱氨酸的表观利用率具有显著抑制作用（P<0.05）。研究结果表明持续低剂量金霉素与蛋氨酸和赖氨酸具有交互作用,这种互作关系影响彼此对肉仔鸡生产性能的作用效果,金霉素具有提高肉仔鸡赖氨酸需要量的作用。     

Quantitative analysis of canine plasma lipoproteins

A combined ultracentrifugationl/precipitation method for the measurement of lipoprotein cholesterol concentrations was developed and validated for use with canine plasma. Very low density lipoproteins (VLDL) were isolated by flotation ultracentrifugation and low density lipoproteins (LDL) separated from high density lipoproteins (HDL) by precipitation with heparin-manganese chloride. Effective separation of these classes was confirmed by agarose gel electrophoresis of native lipoproteins and by sodium dodecyl sulphate polyacrylamide gel electrophoresis of their apolipoprotein distributions. There was trace contamination of the LDL precipitate with HDL, but this represented less than 4 and 9 per cent of the total plasma HDL in normo- and hypercholesterolaemic dogs, respectively. The intra-assay and interassay coefficients of variation for LDL- and HDL-cholesterol concentrations were between 3·3 and 6·9 per cent, and 7·2 and 9·0 per cent, respectively, for plasma cholesterol concentrations between 2·67 and 8·14 mmoll/litre. The intra-assay coefficient of variation for VLDL-cholesterol was 53·8 and 18·4 per cent at plasma cholesterol concentrations of 2·67 and 8·14 mmol/litre, respectively. The interassay coefficient of variation for VLDL was 22·5 per cent. Storage of plasma at -20°C for between two and eight weeks did not affect VLDL-cholesterol concentrations, but led to an increase in LDL-cholesterol and a decrease in HDL-cholesterol concentrations of approximately 10 per cent. The method described is appropriate for the measurement of lipoprotein concentrations in plasma from normo- and hypercholesterolaemic dogs, but samples should not be subjected to prolonged storage before analysis.     

Dyserythropoeisis, sideroblasts/siderocytes and hemoglobin crystallization in a dog

Dyserythropoiesis characterized by enhanced intramedullary destruction, pathologic sideroblasts and siderocytes, and hemoglobin crystallization was detected in a female Cocker Spaniel presented for poor exercise tolerance. Examination of peripheral blood revealed intraerythrocytic crystals, granulation of erythrocytes, nucleated erythroid cells, reticulocytosis and marked variation in erythrocyte morphology in the absence of anemia. Bone marrow examination revealed sideroblasts, a low M:E ratio and evidence of enhanced intramedullary destruction of erythroid cells. Electron microscopy of peripheral blood and bone marrow confirmed pathologic mitochondrial iron accumulation in erythroid cells and the presence of intraerythrocytic hemoglobin crystals. A cause for the hematologic changes was not identified. After the animal became clinically normal, siderocytes disappeared from peripheral blood but intraerythrocytic crystals and reticulocytosis persisted.