What are laboratory mice fed? - briefly
Laboratory mice receive a sterile, nutritionally complete rodent diet formulated with precise amounts of protein, carbohydrates, fats, vitamins, and minerals, often supplied as pelleted or powdered chow. Specialized studies may add defined supplements or custom formulations, but the baseline feed is a controlled, pathogen‑free chow designed for consistent growth and health.
What are laboratory mice fed? - in detail
Laboratory mice receive nutritionally balanced, sterilized chow formulated to meet the physiological demands of specific strains and experimental protocols. The primary product is a pelleted diet containing 18–20 % protein (usually casein or soy), 4–6 % fat, 5–7 % fiber, and defined levels of carbohydrates, vitamins, and trace minerals. Energy density is typically 3.0–3.5 kcal g⁻¹, providing sufficient calories for growth, reproduction, and maintenance.
Supplementary feeds address particular research needs:
- Purified (synthetic) diets: chemically defined ingredients, low in unknown variables, used for metabolic studies.
- High‑fat formulations: 45–60 % calories from fat, employed to model obesity or insulin resistance.
- Low‑protein or amino‑acid‑defined diets: adjust protein content to 5–10 % for studies of protein restriction.
- Vitamin‑ or mineral‑deficient versions: enable investigation of specific nutrient deficiencies.
Water is supplied ad libitum through autoclaved bottles or automated dispensing systems, ensuring constant access while preventing microbial contamination. Some protocols incorporate sucrose or electrolyte solutions to evaluate taste preference or fluid balance.
Feeding schedules vary according to experimental design. Most facilities adopt ad libitum access, but controlled restriction (e.g., 70–80 % of normal intake) is applied to study caloric limitation or to synchronize physiological states. Automated feeders can deliver precise portions at defined intervals, reducing human handling and variability.
Quality assurance measures include:
- Sterilization: gamma irradiation or autoclaving eliminates pathogens.
- Batch testing: analysis of nutrient composition, mycotoxin levels, and microbial load before release.
- Documentation: lot numbers, expiration dates, and storage conditions recorded for traceability.
Age, sex, and genetic background influence dietary requirements. Juvenile mice need higher protein (≈22 %) for rapid growth, while aged animals may benefit from increased fiber and reduced fat to support gastrointestinal health. Sex‑specific formulations adjust calcium and phosphorus to accommodate reproductive demands.
Overall, the diet of laboratory mice is a rigorously controlled component of experimental design, tailored through ingredient selection, nutrient density, and feeding regimen to align with the scientific objectives of each study.