不同颗粒饲料硬度对实验小鼠生长繁殖、饲料利用率及环境粉尘量的影响

Effects of Different Pellet Feed Hardness on Growth and Reproduction,Feed Utilization Rate,and Environmental Dust in Laboratory Mice

目的研究不同颗粒饲料硬度对实验小鼠生长繁殖性能、饲料利用率和笼内环境粉尘的影响。方法选用3周龄的SPF级C57BL/6JGpt和ICR实验小鼠各150只,随机平均分成3组,雌雄各半,分别饲喂饲料硬度为18.62 kg(1kg=9.8N)、23.15 kg和27.89kg的日粮,记录并计算3~10周龄小鼠体重增加量、饲料利用率和笼盒内粉尘量。另外,两个品系各选取45只6周龄雄鼠和90只4周龄雌鼠,随机平均分为3组,分别饲喂3种不同硬度的颗粒饲料。饲喂同一种硬度饲料的同品系小鼠适应2周后,以1∶2的比例雄雌合笼饲养,3个月内每周统计每个繁殖笼内动物繁殖信息。结果C57BL/6JGpt小鼠4周龄时,饲料硬度23.15 kg组的雄鼠体重显著高于饲料硬度为18.62 kg和27.89 kg组(P<0.01),饲料硬度18.62 kg组的雌鼠体重显著高于27.89 kg组(P<0.05);不同饲料硬度组间3~10周龄ICR小鼠的体重无显著差异(P>0.05)。饲喂不同硬度饲料组中,两个品系各周龄雄鼠的饲料利用率均高于雌鼠(P<0.01)。与饲料硬度27.89 kg组相比,饲料硬度18.62 kg组和饲料硬度23.15 kg组4~8周龄(除7周龄C57BL/6JGpt小鼠外)两品系笼盒内50目粉尘量均显著增加(P<0.05)。C57BL/6JGpt和ICR小鼠在实验周期内初产胎间隔及月生产指数等基本繁育性能在3种不同硬度饲料组间均无显著差异(P>0.05);但C57BL/6JGpt小鼠月生产指数随饲料硬度升高先增加后降低,ICR小鼠月生产指数则随饲料硬度升高而增加,但差异尚无统计学意义(P>0.05)。结论不同品系、不同性别的实验小鼠对饲料硬度的耐受性不同,其中C57BL/6JGpt小鼠适合选择较低硬度的饲料,而ICR小鼠适合选择略高硬度的饲料。

Objective To study the effects of different pellet feed hardness on the growth and reproduction,feed utilization rate,and environmental dust in laboratory mice.Methods One hundred of fifty 503-week-old SPF-grade C57BL/6JGpt and 150 ICR laboratory mice were randomly divided into three groups,with an equal number of males and females.They were fed diets with different hardness of 18.62 kg,23.15 kg,and 27.89 kg.Body weight,feed utilization rate,and dust levels in cages were recorded and calculated for mice aged 3-10 weeks.Forty-five 6-week-old male mice and ninety 4-week-old female mice from each strain were randomly divided into three groups and fed pellet feeds with three different hardness levels.After 2 weeks of adaptation to the same hardness feed,the mice were paired at a 1∶2 male-to-female ratio and monitored for reproductive data for 3 months.Results At the age of 4 weeks,the body weight of male C57BL/6JGpt mice in 23.15 kg group was significantly higher than that in the 18.62 kg and 27.89 kg groups(P<0.01),and the body weight of females in the 18.62 kg group was significantly higher than that in the 27.89 kg group(P<0.05).There was no significant difference in body weight among ICR mice aged 3-10 weeks across different feed hardness groups(P>0.05).For both strains,feed utilization rate for males was higher than that for females across different feed hardness groups at all weeks of age(P<0.01).Compared to the 27.89 kg group,both the 18.62 kg and 23.15 kg groups showed a significant increase in the 50-mesh dust levels in cages for both strains aged 4-8 weeks(except for 7-week-old C57BL/6JGpt mice)(P<0.05).For both C57BL/6JGpt and ICR mice,there was no significant difference in basic reproductive performance such as interval between the first litter and the monthly production index among the three feed hardness groups during the experimental period(P>0.05).However,the monthly production index of C57BL/6JGpt mice first increased and then decreased with the increase of feed hardness,while that of ICR mice increased with increasing feed hardness,though these differences were not statistically significant(P>0.05).Conclusion Different strains and genders had different tolerance to feed hardness.C57BL/6JGpt mice are more adapted to lower hardness feeds,while ICR mice are better suited to slightly higher hardness feeds.