How much food should be given to a rat each day? - briefly
Adult laboratory rats typically consume 15–20 g of standard pelleted feed each day, with amounts adjusted for size, age, and activity level. Juvenile rats require roughly 10–12 g daily, increasing as they mature.
How much food should be given to a rat each day? - in detail
A typical adult laboratory rat (250–300 g) requires roughly 15–20 g of a nutritionally complete pelleted diet each day. This amount supplies about 70–100 kcal, representing 3–5 % of the animal’s body weight in energy. Younger rats (weanlings) consume 5–7 g per 100 g of body mass, while pregnant or lactating females need 30–40 g to meet the increased metabolic demand.
Key variables influencing daily ration:
- Body weight: Provide 3–5 % of the current mass in dry feed.
- Age and growth stage: Juveniles require higher protein and caloric density per gram.
- Reproductive status: Gestating or nursing females need an additional 10–15 g of high‑energy pellets.
- Ambient temperature: Cooler environments raise the thermogenic requirement, adding 2–4 g per day.
- Activity level: Enriched cages or exercise wheels may increase intake by 5–10 %.
Feeding strategies:
- Ad libitum access: Unlimited supply of dry pellets; animals self‑regulate intake, typically staying within the 15–20 g range for adults.
- Measured portions: Provide calculated grams at the same time each day; useful for weight‑control studies.
- Supplemental wet food: Up to 5 g of moist diet can be offered, but water content reduces caloric density, so dry feed must be adjusted accordingly.
Water should be available continuously, as dehydration quickly alters food consumption and metabolic rate.
Example calculation for a 280 g adult male:
- Base intake: 280 g × 0.04 = 11.2 g (minimum) to 280 g × 0.07 = 19.6 g (maximum).
- Add 2 g for housing temperature of 20 °C.
- Total recommended: ≈ 21 g of dry pellets per day.
Monitoring body weight weekly ensures the diet meets the animal’s physiological needs and allows prompt adjustments.