Effects of Taurine on Broiler Aortic Endothelial Apoptosis Induced by Heat Stress.

Heat stress is an environmental factor that causes severe economic loss to the current intensive breeding industry and induces huge impact on the long-term growth in livestock and poultry industry. Many animal experiments confirmed that heat stress is a major cause of heat stroke death, which is due to severe damage to endothelial cells. In order to provide a theoretical basis for the treatment or mitigation of heat stress related diseases in broilers, the effect of taurine on injury and apoptosis of aortic endothelial cells in broilers under heat stress was investigated in the present study. Ten days healthy broilers were sacrificed, then aortic tissue was used to isolate and cultivate primary broiler aortic endothelial cells. The third to the fifth generations of cells were used in the experiment. The cells were randomly divided into five groups, including control group (C), heat stress group (HS), low taurine (HS+LTau) group, mild taurine (HS+MTau) group and high taurine (HS+HTau) group. Cells in all groups were cultivated for 24 h in cell incubator (37 °C, 5% CO2). Then the heat stress group cells were cultivated in a 43 °C thermostatic water bath for 6 h under heat stress, and then re-incubated under 37 °C for 1 h. The results showed that compared with the control group, expression levels of Bax, Caspase-9, Caspase-3, Cyt-c, P53 and other pro-apoptosis factors in HS groups were significantly increased (P < 0.05), while expression levels of anti-apoptosis factor Bcl-2 showed a significant decrease (P < 0.05). Compared with HS group, expression levels of Bcl-2 in endothelial cells were significantly increased by taurine administration (P < 0.05), while expression of Bax, Caspase-9, Caspase-3, Cyt-c and P53 were significantly increased by taurine (P < 0.05). In summary, the present data indicated that taurine could protect against injury and apoptosis of aortic endothelial cells under heat stress by inhibiting the activation of mitochondria-mediated apoptotic pathways.

Effects of recombinant goose adiponectin on steroid hormone secretion in Huoyan geese ovarian granulosa cells.

Adiponectin is an adipokine associated with the regulation of reproductive processes. To determine whether recombinant goose adiponectin contributes to the goose ovarian steroidogenesis, the native and then purified goose recombinant adiponectin protein was produced using recombinant DNA technologies. The effect of recombinant adiponectin on the progesterone (P4) and estradiol (E2) production in Huoyan geese ovarian granulosa cells was examined. Furthermore, the effect of recombinant adiponectin (2.5 µg/mL) on the abundance of StAR (steroidogenic acute regulatory protein), CYP11A1 (cytochrome P450scc, cholesterol side-chain cleavage enzyme) and CYP19A1 (cytochrome P450 aromatase) mRNA and protein in granulosa cells was evaluated. Results indicate that a 24-h treatment with recombinant adiponectin (2.5 µg/mL) affected P4 and E2 production by geese ovarian granulosa cells by stimulating P4 production (P < 0.01) and weakly inhibiting E2 production (P > 0.05). Furthermore, when the results with treatment were compared to when there was not adiponectin treatment, the abundance of StAR and CYP11A1 mRNA was greater (P < 0.05) while the CYP19A1 mRNA slightly decreased (P > 0.05). In addition, the fluorescence intensity of StAR tended to be greater compared to PBS-treated (P < 0.05) and control groups (P > 0.05) and StAR protein abundance was greater (P < 0.05) compared to the other two groups. The fluorescence intensity and protein abundances of CYP11A1 increased (P < 0.05) while those for CYP19A1 tended to decrease (P > 0.05) after adiponectin treatment. The results indicate recombinant goose adiponectin affects steroidogenesis and/or hormone secretion of geese ovarian granulosa cells. There may, therefore, be important functions of adiponectin in goose reproductive physiology.

Effects of Taurine on ACE, ACE2 and HSP70 Expression of Hypothalamic-Pituitary-Adrenal Axis in Stress-Induced Hypertensive Rats.

The experiment was to elucidate protective mechanism of taurine against stress-induced hypertension. Thirty two male Wistar rats were randomly divided into four groups. Normal control group and stress control group were intragastrically administered saline; ß-alanine stress group were fed with ß-alanine (200 mg/kg/day) and taurine stress group with taurine (200 mg/kg/day). The hypertensive model was established by giving rats stress for 3 weeks.Results showed that significant expression levels of angiotensin converting enzyme (ACE) in the hypothalamus, pituitary and adrenal were observed in ß-alanine stress group and stress control group (P < 0.05), but significant mRNA expression levels of angiotensin-converting enzyme 2 (ACE2) in taurine stress group and normal control group (P < 0.05). All the groups showed no significant differences in HSP70 mRNA expression levels in hypothalamus (P > 0.05), while taurine stress group exhibited the highest HSP70 mRNA expression levels both in pituitary and in adrenal (P < 0.05). It was also found that ß-alanine stress group and stress control group had significantly higher protein expression levels of ACE in hypothalamus, pituitary and adrenal (P < 0.05), but significantly lower protein expression of ACE2 compared to taurine stress group and control groups (P < 0.05). The results indicated that taurine regulated the hypothalamus pituitary adrenal (HPA) axis of the renin-angiotensin-aldosterone system (RAAS) by inhibiting ACE gene and protein expressions and promoting ACE2 and HSP70 protein expressions, thereby contributing to the prevention of stress-induced hypertension.

Effects of Replacement of Methionine in Diets with Taurine on Growth Performance and Blood Index in Broilers.

We studied effects of replacement of methionine with taurine on growth performance and blood index of AA+ broilers. Six hundred 1 day broilers were divided into 5 groups, with 3 replicates of 40 broilers in each. The experiment lasted for 42 days.The control group were fed on formulated diets containing 2% methionine; the other groups were offered feed with equal nitrogen and calories to the control group, but contained 25, 50, 75 and 100% taurine in place of methionine.Compared with the control group, no significant differences were observed in growth performance of 1-21 days broilers, or the serum LDL-C, TC, IgG and SOD of the experimental groups (P> 0.05). ADG and F/G from days 1-42, ADG, ADFI and F/G from days 22-42 were significantly different between the experimental groups and the control group (P < 0.05). ADFI and Mortality in 50, 75 and 100% taurine groups were significantly different compared with the control group (P < 0.05). IgM and GSH-PX of 50 and 75% taurine groups were significantly different compared with the control group (P < 0.05). Serum HDL-C, T-AOC levels in 50, 75 and 100% taurine groups were significantly different compared with the control group (P < 0.05). Based on the quadratic regression analysis, the best replacement ratios were 58%, 61% and 61% on days 1-21, 22-42, and 1-42, respectively. In conclusion, appropriate levels of taurine supplement can improve growth performance, immune system, T-AOC, and lipid metabolism.