Correction factors derived from measurements (cm) of length and circumference (measured at 3–5 points along its length) of the ileum, allowing comparisons of nerve density in the small intestine from the different groups of animals (see methods). Data for 24 month RD rats from Johnson and colleagues15
| Age group (months) | n | Length (cm) | Circ. (cm) | Area (cm2) | Correction factor |
| 4–6 m | 16 | 110 (3) | 1.3 (0.03) | 136 (5) | Standard |
| AL 16 m | 4 | 118 (10) | 1.5 (0.04) | 175 (15) | 1.29 |
| AL 24 m | 9 | 111 (4) | 1.4 (0.04) | 159 (7) | 1.17 |
| RD 24 m | 10 | 145 (4) | 1.3 (0.03) | 194 (5) | 1.43 |
| DRD 30 m | 4 | 110 (3) | 1.5 (0.01) | 159 (6) | 1.17 |
AL, ad libitum; RD, restricted diet; DRD, double restricted diet.