Superovulation and Embryo Recovery in the Guinea Pig
Mice and rats are the most popular lab animals used in experiments across the world. They are also routinely used in studies about the reproductive system due to their large litter number, short gestation period and the ease of inducing ovulation. A large oocyte supply is also crucial for the preservation of genetic resources, conservation of endangered species, transgenesis, or cloning by nuclear transfer (Coello et al.). They are cheap and easy to maintain, while readily available in every country. The guinea pig (Cavia porcellus) has been used as a laboratory animal since the 1700’s (Terrill and Clemons, 1998) but has decreased in popularity in the lab throughout time. Despite being a rodent, the guinea pig is thought to be evolutionary different from mice and rats; there are many anatomical, reproductive and physiological differences which will be discussed later on.The reason why it has been used less frequently in the field of reproduction is the fact that they have a smaller litter number and a longer gestation period. It is also relatively difficult and time consuming to induce superovulation, especially since ovulation cannot be induced spontaneously as in mice and rats. Even so, there are many reasons why the guinea pig has been preferred for the study of human reproduction, all of which have motivated scientists across the world to work on improving methods of superovulation in order to collect larger amounts of oocytes or embryos for their studies.