Effects of diets with different energy and bile acids levels on growth performance and lipid metabolism in broilers.

This experiment was conducted to evaluate the effects of bile acids (BAs) on the growth performance and lipid metabolism of broilers fed with different energy level diets. 480 one-day-old Arbor Acres broilers (45.01 ± 0.26 g) were allotted to a 2 × 2 factorial design with 2 levels of energy (basal or high-energy level) and 2 levels of BAs (with or without BAs supplementation), resulting in 4 groups of 8 replicates; the experiment lasted 42 d. High-energy diets decreased the feed/gain ratio (F/G) from 1 to 21 d (P < 0.05), and increased the liver index and abdominal fat percentage at 42 d (P < 0.05). The serum total triglyceride (TG) and high-density lipoprotein cholesterol at 42 d were increased by high-energy diets (P < 0.05), while the hepatic lipoprotein lipase (LPL) activity at 21 and 42 d was decreased (P < 0.05). BAs supplementation increased the body weight at 21 d and decreased the F/G during entire period (P < 0.05), as well as improved the carcass quality reflected by decreased abdominal fat percentage at 42 d and increased breast muscle percentage at 21 and 42 d (P < 0.05). The serum TG at 21 and 42 d were decreased by BAs (P < 0.05), and the hepatic LPL activity at 42 d was increased (P < 0.05). In addition, high-energy diets increased the expression of sterol regulatory element binding transcription factor 1, acetyl-CoA carboxylase, and fatty acid synthase (P < 0.05), while BAs diets decreased these genes expression (P < 0.05). Moreover, BAs supplementation also increased the expression of carnitine palmitoyltransferase 1 (P < 0.05), which was increased in high-energy groups (P < 0.05). In conclusion, BAs supplementation could increase growth performance, elevate carcass quality, and improve lipid metabolism in broilers.

Effects of Ilexonin A on circulatory neuroregulation.

Ilexonin A (IA), a pentacyclic triterpene, has been semisynthesized in china for the first time. It is extracted from the root of Ilicis pubescentis, a commonly used herbal medicine in Guangdong for the treatment of cardiovascular, cerebrovascular and peripheral vascular diseases and heart failure with satisfactory effects. The pharmacokinetic studies indicated that the elimination half-life after oral and i.v. dosing were 17.7 +/- 2.4 h and 22.5 +/- 2.9 h respectively. The total clearance was 4.6 +/- 0.51/h. The bioavailability of IA capsules was 0.39 +/- 0.14 and LD50 was 234 mg/Kg. We have adopted modern techniques, including cellular electrophysiology, isotope tracing methods, molecular biology, electromicroscopy, etc., to probe into the pharmacologic mechanisms of the effects of IA on cardiovascular system. The results indicated that IA can increase the contractility of isolated guinea pig auricular myocardium, attenuate vascular smooth muscle tension induced by noradrenaline in the rabbit aorta. IA can exert a biphasic regulatory effect on arterial blood pressure. IA also can prolong A-V duration of Hiss bundle electrograph (HBE) in rabbits and prolong the action potential duration and the effective refractory period (ERP) of myocardial cells in guinea pigs. The results showed that IA can increase the cAMP content in the smooth muscle of aorta and exert a calcium-blockade effect. Therefore, the peripheral resistance vessels are relaxed and the cardiac afterload is lowered. IA-blocked calcium channels are correlated with both the potential-dependent channel and the receptor operated channel in vascular smooth muscles. IA also increases the cAMP content of myocardium and accelerates the cellular calcium influx and efflux, and this may be responsible for the direct mechanism of the positive inotropic action of IA. Under electron microscopy, it is observed that IA can alleviate the defect of succinate dehydrogenase in the myocardial mitochrondria of rabbit chronic congestive heart failure (CF) model and reduce the microstructural damage of the failed myodardium, therefore the anoxic tolerance of myocardium is increased, the effect of IA on the platelet stretching activity and microstructure in the patients with CF is also studied. It is found that IA can reduce the hypercoagulability of blood, decrease the severity of blood stagnation and improve the status of microcirculation. Effects of IA introventricular and cardiovascular central microinjection (nucleus tractus solitarius, paraventricular nucleus) on arterial blood pressure and heart rate were studied. It demonstrated that IA possess circulatory neuroregular effects by the medium of alpha-receptor and beta-receptor of cardiovascular motoneurons.