禁食、急性冷暴露和外源性注射Ghrelin对羔羊生理指标的影响

Effects of Fasting,Cold Exposure and Exogenous Ghrelin Injection on Physiological Indexes in Lambs

为了探究禁食、急性冷暴露和注射外源性生长激素释放肽Ghrelin对羔羊生理指标的影响,本研究监测了室温禁食24h后继续禁食并冷冻(-24.7℃±0.2℃)2h羔羊基本生命体征、血液生理指标和血糖浓度的变化,同时探究了外源性Ghrelin对于冷冻的禁食羔羊以上指标的影响。结果显示,在禁食后8、16、24h羔羊呼吸频率、心率和血糖浓度均较禁食前显著降低(P<0.05),在禁食后16h和24h直肠温度均较禁食前极显著降低(P<0.01),而血液生理指标变化不明显(P>0.05);在冷冻1.5h和2.0h后羔羊呼吸频率较保温组显著减慢(P<0.05),心率和血糖浓度在冷冻后1.0、1.5、2.0h显著增加(P<0.05),冷冻过程中羔羊直肠温度差异不显著(P>0.05);冷冻2h后颈静脉一次性注射Ghrelin未发现对羔羊以上指标的影响(P>0.05)。以上研究结果提示,羔羊在禁食和低温情况下可通过调整自身活动,以维持机体稳态,并且Ghrelin可能并未参与该调整过程。

In order to explore the effect of acute cold exposure and exogenous injection of ghrelin on physiological indexes of lambs, basic vital signs, physiological indexes and blood glucose concentration of lambs were monitored after fasting for 24 h,then freezing （-24.7 ℃± 0.2 ℃） for 2 h. Moreover,changes of above indexes of lambs by exogenous ghrelin injection were determined. The results showed that breathing rates,heart rates and blood glucose concentrations after fasting for 8 h, 16 h and 24 h were significantly decreased compared with that before fasting （P〈0.05）. Rectal temperature after fasting for 16 h and 24 h were significantly reduced compared with that before fasting （P〈0.01）, however, blood physiological indexes had no changes during the fasting period （P〉0.05）. Breathing rates after cold exposure for 1.5 h and 2 h were slowed compared to warm groups （P〈0.05）,however,heart rates and blood glucose concentrations after cold exposure for 1.0 h,1.5 h and 2 h were significantly increased （P〈0.05）. Changes of above indexes were not found by intravenously injecting ghrelin after 2 h of cold exposure （P〉0.05）. These results indicated that lambs in the fasting and low temperature conditions can adjust their activities to maintain the body homeostasis,and ghrelin may not be involved in the process.