食物蛋白含量和限食对雌性东方田鼠生理特性的影响

为了研究食物蛋白含量和限食对雌性东方田鼠生理特性的影响,实验以成年雌性东方田鼠为对象,在控制其他因子一致的条件下,依据食物条件设置4个处理组:20％蛋白质+自由取食、20％蛋白质+70％限食、10％蛋白质+自由取食、10％蛋白质+70％限食.经过4周的食物驯化,测定了动物体重、动情周期、雌激素(雌二醇、孕酮、卵泡刺激素)和内脏器官(脾脏、肝脏、肾脏、子宫)湿重等指标.结果发现:(1)限食70％使东方田鼠体重减少,动情期缩短,脾脏、肝脏、肾脏及子宫湿重均显著减轻.(2)10％蛋白含量降低了脾脏湿重和肝脏湿重,但未显著影响体重、肾脏湿重和子宫湿重.(3)蛋白和限食均未影响雌二醇、孕酮、卵泡刺激素的含量及动情周期的长短.实验结果表明,在食物资源不理想的情况下,成年雌性东方田鼠通过降低体重来维持基本生存,内脏器官重量也相应地减轻,但是与繁殖相关的生理特性变化不显著.相对与食物蛋白含量,可获得的食物量的多少是引起东方田鼠生理变化的主要因素.实验结果反映出食物资源对成年雌性东方田鼠的生理特性产生了影响,但这些影响对其繁殖行为的调控强度及季节性的种群波动的作用还需结合其他相关方面做进一步探究.

Effects of dietary protein content and food restriction on the physiological characteristics of female Microtus fortis

Food plays a vital role in the survival of animals. Previous findings have shown that food restriction and food quality have a significant effect on body growth, endocrine, reproduction and other physiological characteristics. These results also indicated that changes in food consumption can affect breeding behavior and population fluctuation. Therefore, the present study aims to explore the effects of dietary protein content and food restriction on the physiology of adult female Microtu fortis. Forty animals were randomly divided into four groups and were allowed to acclimatize themselves to the following four regimens: (1) high-protein (20% protein content) and free-feeding diet, HF; (2) high-protein (20% protein content) and restricted to 70% free-feeding diet, HR; (3) low-protein (10% protein content) and free-feeding diet, LF; and (4) low-protein (10% protein content) and restricted to 70% free-feeding diet, LR. After a four-week treatment, body mass, estrous cycle, and fresh weight of the visceral organs (spleen, liver, kidney, and uterus) were determined. Female hormone level (estradiol, progesterone, and follicle stimulation hormone) were also measured using enzyme-linked immunosorbent assay. The results showed the following. First, the influence of food restriction was remarkable. When the food intake was restricted to 70% of the voluntary intake, the body mass significantly decreased, and the estrus period was shortened. Similarly, the fresh weight of the spleen, liver, kidney, and uterus was significantly lessened compared with that of the free-feeding groups. Second, the reduction in the level of protein content in the diet clearly lightened the fresh weight of spleen and liver. However, no significant difference was shown in terms of body mass and fresh weight of the kidney and uterus between the 10% and 20% protein content food group. Third, different protein contents and food-restricted degrees have no effect on the estrus cycle, serum estradiol, progesterone and follicle stimulation hormone level. In addition, an interaction between protein content and food restriction was not observed. In conclusion, the results indicated that when food resources are limited, female M. frotis reduced their body mass for basic survival, and accordingly, the fresh weight of their visceral organs was reduced. Compared with food protein content, the amount of food available played an important role in the physiology of adult female M. frotis. However, the role of food resources in the regulation of reproductive behavior and seasonal change in M. frotis needs further examination.