How litter size influences the body composition of Rattus norvegicus

The management during the lactation period is crucial for the development of animals, positively or negatively impacting their growth depending on the quality of the practices adopted. Studies have shown that animals subjected to proper management tend to present higher weights at weaning compared to those that do not receive such care. The present study randomly selected ten cages containing female Mercois that gave birth on the same day. Among them, five cages (Batch 1) were limited to eight pups per female, while the remaining were discarded. The five remaining cages (Batch 2) retained the total number of born pups, varying between 14 and 21. At weaning, the animals of Batch 2 exhibited sizes and weights consistent with the expected standards, with average sizes of 7.5 cm and average weights of 22 g. In contrast, individuals from Batch 1 presented average sizes of 9.5 cm and average weights of 34 g. Additionally, Batch 1 displayed an average of 204 kcal/g, while Batch 2 recorded 175 kcal/g. Statistical analysis indicated a significant difference in the caloric averages between the two batches, with a p-value of 0.0276 and a 95% confidence interval for the difference between the means. It is concluded that the size of the litter during the lactation period exerts a significant influence on the weight, dimensions, and energetic values of rodent carcasses.