The primary housing cage should be made of strong, easily cleaned material, such as stainless steel, polypropylene plastic, or glass (e.g., fish aquarium).  The cage must be equipped with a cover to prevent escape.  No resting surface is required as Xenopus frogs are totally aquatic.  Adult frogs should be kept one animal per two liters of water at 5-10 centimeters deep.  Low population densities result in healthier animals and improved water quality.  State of California regulations indicate, "Containers... shall be labeled with the identification of the current species and the number of animals contained inside."

Investigators who manage animal housing facilities must submit to the ARC a Standard Operating Procedure for maintaining these areas.

Water

Water systems may be continuous flow-through, recycling, or no flow.  Continuous flow systems are considered to be the best with respect to aspects of cleanliness, water quality, and temperature control.  Water should be chlorine-free and should be chemically dechlorinated because of the potential presence of chloramines in municipal water.  The pH should be from 7.5-8.5 and should be checked daily in flow-through systems.  The oxygen content of the water should be 5 mg O₂/ml H₂0.  An air bubbler is recommended for non-flow systems to prevent the water from being stagnant.  State of California regulations indicate, "There must be covers over all drains and openings to prevent escape of the amphibians from the building."

Detergents should be avoided for routine cleaning, and cages should be rinsed well.  Visually, the water should be clear with minimal debris.  Non-flow systems should be cleaned as needed to minimize cloudiness and debris.

Temperature

The cage should be placed in the room avoiding areas of fluctuating temperatures, e.g., windows, radiators, or vents.  Xenopus laevis should be housed at 20-23° C (68-75° F).  Xenopus tropicalis should be housed at 23-28° C (75-80° F).

Frogs should be kept with a diurnal light cycle (12 hours light: 12 hours dark).  Full spectrum lighting (including UV range) is recommended for animals kept longer than six months.

Xenopus frogs should be fed a commercial nutritionally balanced frog diet, following the recommendations of the manufacturer regarding the volume and frequency.  Frogs are usually fed daily or every other day.  It is recommended to feed only as much as will be eaten in one hour; this limits waste and preserves water quality.  Frogs should not be handled immediately following eating, as they may regurgitate. 

Tanks should be cleaned after feeding to remove uneaten food.  This can be done using a siphon.

Enrichment

Hiding places that are appropriate to the amphibian's nature minimize stress.  Floating sheets of dark plastic (or plastic mimics of large-leafed water plants) must be provided.  Refuges should be inspected regularly for sick or injured animals.  Materials used for enrichment devices should have smooth surfaces and rounded edges to minimize the risk of injury to the amphibian's skin.  They should be cleaned following the same schedule and procedures used for the cages.

Transportation

State of California regulations indicate, "Transfer containers shall have locked tops and shall be constructed in a manner which shall prevent the likelihood of escape."

The state of California's Department of Fish and Game requires a permit for import, transport, and possession of detrimental species.  Since Xenopus is considered a detrimental species, this requires UCLA to secure and maintain a Restricted Species Permit.  This permit authorizes UCLA and its investigators to acquire, maintain, and breed these animals for purposes of research, teaching, and testing.  This permit requires annual renewal, and is in addition to the other applicable regulations.  In keeping with the spirit of the regulations, the Division of Laboratory Animal Medicine (DLAM) needs the following information:

• Provide the facility veterinarian an inventory of the number of Xenopus frogs on July 1 of each calendar year, or more frequently as requested. The inventory must include the following information:

• Common name

• Scientific name

• Sex

• Age

 

• Xenopus log: The state of California requires a log be kept to document each animal's health care. "The log shall contain the following information:"

• Date of acquisition,

• Name and address of person from whom the animal was acquired,

• Identifying marks or characteristics,

• Date and description of illness and/or injury,

• Health care treatment provided with the name and signature of the person treating the animal.

Care for the first 2 weeks following arrival is critical for amphibian survival.  Below are recommendations to enhance survival:

• Quickly transfer the amphibians into clean and sanitized containers containing water from the shipment container.

• Slowly acclimate to dechlorinated laboratory water by gradual dilution of their shipment water.  Any temperature change should not exceed 1 °C/hr.

• Animals appearing ill or injured should be isolated from others and treated or sacrificed.

• "Red Leg" or bacterial septicemia is the most commonly reported problem in frogs.  Clinical signs include anorexia, lethargy, cutaneous ulcers, dull discoloration or skin pallor, and cutaneous hemorrhages.  Adding antibiotics to the water is generally ineffective.  This or any other health problem should be reported to the DLAM veterinary staff.

• Xenopus are susceptible to Chlamydophyla.  Feeding liver certified for human consumption or a commercially prepared diet, and preventing contact with feral animals, should prevent exposure to this potentially zoonotic agent.

• New arrivals must be quarantined for 2 weeks.  These animals must be handled last.

• Please contact a member of the DLAM veterinary staff (x42571) to discuss any problems with Xenopus frogs.

Schultz, T.W., Dawson, D.A. 2003. Housing and husbandry of Xenopus for oocyte production.  Lab Animal (NY) 32(2):34-39.

National Academy of Sciences. Amphibians: Guidelines for the Breeding, Care, and Management of Laboratory Animals. National Academy Press, Washington, D.C.

Major, N. and R.J. Wassersug. 1998. Survey of current techniques in the care and maintenance of the African clawed frog (Xenopus laevis). Contemporary Topics 37(5):57-60.

California Code of Regulations. February 1999. Listing of Endangered and Threatened Species. Title 14: Division 1, Subdivision 3, Chapter 3 (671).

California Code of Regulations. February 1999. Humane Care and Treatment Standards. Title 14: Division 1, Subdivision 3, Chapter 3 (671.2-3).

Approved 9/11/00

Revised 3/22/04