复合微量营养素对营养缺乏小鼠游泳耐力的影响及其机制

目的 研究复合微量营养素的抗疲劳效果及可能机制.方法 取SPF级雄性昆明种小鼠125只,分别以下述不同的饲料喂养.全营养素饲料.即AIN-93M饲料,主要成分和比例为:玉米淀粉46.6％、酪蛋白14％、糊精15.5％6.蔗糖10％、豆油4％、纤维素5％、矿物盐粉3.5％、维生素粉1％、胱氨酸0.18％、叔丁基氢醌8ppm.营养素缺乏饲料,在AIN-93M饲料的基础上将维生素粉和矿物盐粉减少为原来的70％、50％或30％(后称70％、50％、30％微量营养素饲料),其余以淀粉补足.复合微量营养素粉添加饲料,在营养素缺乏30％饲料的基础上,将减少的维生素粉和无机盐粉以复合微量营养素粉补足,其主要成分及含量(g/kg)为:VitA 0.25、VitB10.3、Vit B2 0.3、Vit B6 0.35、烟酸1.5、VitD 0.05、VitC50、VitE 10以及碳酸钙180、甘氨酸铁1、乳酸锌1、玉米淀粉755.25.分别干喂养14d和28d后取不同饲料(AIN-93M饲料及70％、50％、30％微量营养素饲料)喂养的小鼠,于尾部系5％体重的铅丝进行负重游泳,记录小鼠游泳力竭时间.于喂养至28d时,取不同饲料(AIN-93M饲料及70％微量营养素饲料、复合微量营养素粉添加饲料)喂养的小鼠,使其负重游泳60min,游泳后立即取外周血测定生化指标,取肝组织测定肝糖原含量.结果 与AIN-93M饲料喂养小鼠相比,30％微量营养素饲料喂养小鼠的摄食量显著减少(P＜0.05),50％和70％微量营养素饲料喂养小鼠的摄食量变化并不显著,但70％、50％、30％饲料喂养小鼠的负重游泳时间均显著缩短(P＜0.05).与AIN-93M饲料喂养小鼠相比,营养素缺乏饲料喂养的小鼠负重游泳时间显著缩短(P＜0.05),复合微量营养素粉饲料喂养小鼠游泳时间与营养素缺乏饲料喂养小鼠比较差异无统计学意义(P＞0.05),但延长了13.2％.小鼠游泳后生化指标的变化趋势主要表现为血糖和肝糖原水平下降.乳酸、游离脂肪酸(NEFA)和尿素氮(NPN)水平升高.营养素缺乏饲料喂养小鼠的前述变化更为明显,而复合微量营养素粉饲料可有效缓解营养缺乏所致血糖和肝糖原水平下降,下调血乳酸、NEFA和NPN水平.结论 微量营养素摄入不足对小鼠游泳耐力有明显影响,复合微量营养素具有一定的抗疲劳作用,其机制可能与运动过程机体能量代谢的调控有关.

Effect of micronutrient compound on swimming endurance in mice with nutritional deficiency and its mechanism

Objective To investigate the anti-fatigue effect and possible mechanisms of micronutrient compound.Methods One hundred and twenty-five male Kunming mice(SPF) were fed following different feeding stuffs: sufficient feed,i.e.AIN-93M feed(corn starch 46.6%,casein 14%,dextrinized corn starch 15.5%,sucrose 10%,soybean oil 4%,fiber 5%,mineral mix 3.5%,vitamin mix 1%,L-cystine 0.18% and tert-butylhydroquinone 8 ppm);insufficient feed(composed the same ingredients as the AIN-93M diet,replacing 30%,50% or 70% of the content of mineral and vitamin mix with corn starch);compound micronutrient-added feed(CMAF,replacing 30% of the content of mineral and vitamin mix of AIN-93M diet with micronutrient compound composed of(g/kg) Vit A 0.25,Vit B1 0.3,Vit B2 0.3,Vit B6 0.35,nicotinic acid 1.5,Vit D 0.05,Vit C 50,Vit E 10,calcium carbonate 180,ferrous glycine 1,zinc lactate 1 and corn starch 755.25).The mice were fed for 14 or 28d,and then subjected to forced swim test with a load on their tails to exhaustion.The maximal swimming time was recorded.In another experiment,the Kunming mice were fed with corresponding feed for 28d,and then subjected to forced swim test for 60min,thereafter the samples of blood and liver were collected immediately.The serum contents of glucose,lactate,nonprotein nitrogen,nonesterified fatty acids and hepatic glycogen were measured.Results The dietary intake of 30% nutritional insufficient group(30% group) was significantly decreased compared with normal control group(fed with AIN-93M diet,P<0.05);and there were no significant difference in dietary intake between the two other nutritional insufficient group(50% and 70% group) and normal control group.The swimming time was shorter in three nutritional insufficient groups than in normal control group(P<0.05).Compared with nutritional insufficient group,swimming time to exhaustion for mice CMAF were prolonged by 13.2%,however,the difference was not significant(P>0.05).The serum glucose and hepatic glycogen decreased and serum lactate,nonprotein nitrogen and nonesterified fatty acids increased in the control group,which were aggravated in nutrient insufficient group and reversed in micronutrient supplementation group.Conclusions Insufficient intake of micronutrients has significant influence on swimming endurance in mice and compound micronutrient supplementation may be of an anti-fatigue effect and improve the endurance of mice with malnutrition during exercise,which may be related to the regulation of energy metabolism during swimming.