Effects of foster mother usage in breeding on behavior and physical development of rat pups

Rat pups are born hairless, with closed eyes and ears. For their needs like balancing body heat and nutrition they need maternal care. When pups lose their mother for some reason, they're given to foster mothers in laboratory animal science breeding colonies. When grow older, these pups can be used in scientific research studies. Our aim is to evaluate if using foster mothers in breeding colonies may effect the physiological development and/or pups' behavior parameters. Wistar Hannover rats were used in this study. Six mothers and their pups were divided into foster mother and biological mother groups (3 mothers, 37 pups each). In foster mother group, pups were given to foster mother on PND4. Pups' physiological development was evaluated by their weight gain, time of eruption of insisors, eye opening and pinneal detechment. Anxiety-like behavior was evaluated with elevated plus maze and open field tests. Female pups' maternal behavior was scored. Kruskal-Wallis/ Mann-Whitney-U test was used for analysis of the data. At the end of our study, we found that the foster-bred pups gained weight significantly faster than biological mothers'. On the other hand control group female pups spend significantly more time in center area of EPM. Anxiety like behavior was not observed in the pups of both groups. According to results of the study, we rejected the hypothesis "foster mother breeding has negative impact on development of rat pups". We suggest using foster mothers in breeding units for preventing pup loss and for ethical reasons.