How much should a rat eat per day? - briefly
An adult rat needs about 15–20 g of dry feed per 100 g of body weight daily, which translates to roughly 20–30 g of standard lab chow for a 200‑g animal. Juvenile rats require slightly more, around 25 g per day, to support rapid growth.
How much should a rat eat per day? - in detail
Rats require a diet that supplies roughly 15–20 % of their body weight in fresh food each day. For an adult weighing 300–500 g, this translates to about 45–100 g of combined dry and moist feed. The caloric target is 70–100 kcal per day, with protein making up 18–20 % of the total calories and fat 5–7 %.
A typical feeding plan includes:
- Pelleted laboratory or commercial rodent chow: 20–30 g per day. Pellets provide balanced nutrients and meet the majority of protein, vitamin, and mineral requirements.
- Fresh vegetables and fruits: 15–30 g daily. Suitable items are carrots, broccoli, apple slices, and berries. Limit high‑sugar produce to avoid excess calories.
- Protein supplements: 5–10 g of cooked egg, lean meat, or insect larvae for breeding or growing rats. Adjust upward for pregnant, lactating, or rapidly growing individuals.
- Treats and enrichment foods: No more than 5 g per day. Use sparingly to prevent obesity and digestive upset.
Water must be continuously available in a clean bottle. Rats drink 10–30 ml per 100 g body weight each day; a 400 g adult typically consumes 40–120 ml.
Special circumstances alter the intake:
- Juvenile rats (under 8 weeks): Require 25–30 % of body weight in food, emphasizing higher protein (22–24 %) to support growth.
- Pregnant or nursing females: Increase overall calories by 20–30 % and protein by 2–3 % to sustain litter development and milk production.
- Obese or sedentary rats: Reduce daily ration by 10–15 % and prioritize low‑calorie vegetables to promote weight loss.
Monitoring body condition score weekly helps adjust portions. A healthy rat maintains a sleek coat, visible but not protruding ribs, and an active demeanor. Adjustments should be made gradually to avoid gastrointestinal disturbances.