# Pancreatic amylase activity and development of the gastrointestinal tract in C57BL/6J mice before and after weaning

## TL;DR

This study examines how pancreatic amylase activity and gastrointestinal development change in mice before and after weaning.

## Contribution

The study provides new insights into the timing and patterns of pancreatic amylase activity during weaning in C57BL/6J mice.

## Key findings

- Pancreatic amylase activity significantly increased from 3 to 4 weeks of age, coinciding with weaning.
- Relative pancreas weight increased significantly until 6 weeks of age.
- Relative liver weight increased abruptly from 3 to 4 weeks of age.

## Abstract

In mammals, the period of weaning represents the change from milk consumption to a solid, species-specific diet. This is associated with adaptations of the gastrointestinal tract, including the digestive enzymes. This study aimed to investigate the amylase activity in pancreas tissue and small intestinal content before, at and after weaning in C57BL/6J mice, in addition to determining blood glucose levels, body weight, organ weights and the length of the small intestine and colon. In total, 59 mice were sacrificed at the ages of 12 d, 3, 4, 5, 6, 8 and 10 weeks, to obtain these parameters. Weaning had been set to take place at 21 d. Age groups were statistically compared with one-way analyses of variances (α = 0.05). Body weight followed a non-linear function of age. Relative liver weight increased abruptly from 3 to 4 weeks of age, while relative spleen weight decreased from 4 to 8 weeks of age. Relative pancreas weight increased significantly until 6 weeks of age. Pancreatic amylase activity significantly increased from 3 to 4 weeks of age, corresponding to increasing intake of solid diet at weaning. Amylase activity in small intestinal content did not follow this pattern, possibly because of a non-representative nature of the samples. Further studies are warranted to test for the effect of weaning age, diet and genetic background on amylase activity in mice.

The online version contains supplementary material available at 10.1038/s41598-026-44974-8.