In my lab. normally we don't use a reference of VLDL, LDL or HDL, because there may be changes due to age, sex, food you provide. Usually, we use a small control group of same characteristics to have as normal.
You may be able to obtain serum levels of various parameters from many strains of rats that companies like Harlan sell by contacting them directly and asking for the specific strain that interests you. However, things like VLDL can change based on what they are fed and their age. As Renan pointed out, it is always a good idea in a study to have a control group of animals.
if you are using the kit for detection of VLDL OR LDL it will be benificial for you, because by using very less amount of serum is required to detect the LDL and VLDL , so you go for that
VLDL serum values depends on the strain, diet, age and fasting condition. As the previous answers, I agree that a control group is very useful. For young adult male Albino Wistar rat with a weigth circa 180 g in fasting condition TG/VLDL are 20-30 mG /dL