How can a rat be force‑fed? - briefly
A small‑gauge gavage tube or oral syringe can be used to deliver a measured amount of liquid or soft food directly into the rat’s mouth while it is gently restrained. Insert the lubricated tip at the back of the oral cavity, advance slowly, and dispense the feed at a controlled rate to avoid choking or aspiration.
How can a rat be force‑fed? - in detail
Force‑feeding a laboratory rat requires precise equipment, gentle restraint, and strict adherence to welfare guidelines. The process consists of preparation, restraint, tube insertion, delivery, and post‑procedure monitoring.
Equipment
- Flexible gavage tube (1–2 mm outer diameter, appropriate length for the animal’s size)
- Syringe (1–3 mL) compatible with the tube
- Lubricant (sterile, water‑based)
- Soft cloth or restraining board
- Warm water (for tube softening)
- Recording sheet for volume and time
Preparation
- Warm the gavage tube in warm water for 30 seconds, then dry and lubricate the tip.
- Prepare the meal or liquid diet, ensuring it is at body temperature (37 °C) and free of clumps.
- Fill the syringe with the measured volume; typical dose ranges from 0.5 mL to 1 mL per 100 g body weight, not exceeding 10 mL/kg.
Restraint
- Place the rat on a soft cloth, gently but firmly hold the forepaws with one hand.
- With the other hand, support the head and neck, keeping the mouth slightly open.
Tube insertion
- Align the tube with the oral cavity, advance along the palate, avoiding the tongue.
- Insert until the tip reaches the esophagus, approximately the length from the mouth to the sternum (measure on a dummy rat).
- Confirm placement by observing a brief pause in breathing and a slight resistance; do not force the tube further.
Delivery
- Depress the syringe plunger steadily, delivering the pre‑measured volume over 5–10 seconds.
- Observe the rat for signs of regurgitation or choking; if resistance occurs, stop immediately and withdraw the tube.
Post‑procedure monitoring
- Keep the animal in a quiet area for at least 15 minutes.
- Check for normal respiration, activity, and absence of vomit.
- Record any adverse reactions and the exact volume administered.
Safety and ethical considerations
- Use only when oral intake is insufficient and alternative methods (e.g., voluntary feeding) are unavailable.
- Perform the technique only by trained personnel.
- Follow institutional animal care protocols; excessive frequency or volume can cause esophageal injury, aspiration, or stress.
By following these steps, the practitioner can administer nutrients to a rat reliably while minimizing physiological harm and ensuring compliance with ethical standards.