Animal Protocol for Xenopus,
African Clawed Frog Colony
All Xenopus animals in our colony have been lab-bred in our Wisconsin facility. All are at least five generations removed from any wild-caught stock. Animals are maintained in well water at temperatures ranging from 16º C to 20º C. Nasco's well water tests out at 340 mg/L hardness, 350 mg/L alkalinity, and 490 µmhos/cm conductivity. Note: µmhos/cm = µS/cm (microSiemans per centimeter).
Animals receive a 100% water change daily. They are fed our custom frog diet, Nasco Frog Brittle, which is produced for us by Purina Mills®. The animals are very robust. We maximize animal husbandry to minimize health problems. In the rare event of injury, animals may be bathed in a mild saline solution to promote healing. We avoid use of antibacterial compounds so the usefulness of the animal as a research specimen is not compromised. A prophylactic parasiticidal treatment is given to all mature animals in the colony as standard procedure.*
Recommendation for Care of Xenopus Frogs, Adult
Optimal Temperature: 16º C - 18º C.
Optimal pH: Animals can tolerate a wide range of pH. Aim for somewhere in the 5 to 9 range, neutral preferred.
Light Cycle: 12 dark/12 light acceptable. For long-term care maintain under full spectrum fluorescent lights. Most commercial light manufacturers offer specialty tubes that would be suitable.
Density: Adult frogs should be allotted 1 gallon of water per frog.
Water: Use good quality water. If chlorine or chloramine are present, they should be removed from water prior to use. Not all water treatments or filtering systems can remove chloramine. Check with your municipal water department to see if chloramine has been added to your tap water. If you choose to use deionized water, you may wish to adjust osmotic balance by adding salts back into the water before use.
Do not expose animals to excessive fresh tap water. If you use a flow-through water exchange system, you will need to monitor incoming flow rates. Avoid sudden water temperature fluctuations. Animals can usually tolerate a 5º F increase or 10º F rapid decrease. Adult animals can slowly adjust to temperatures almost down to freezing and up to 90º+ F.
Change water as needed. Depending on the density, this may be once a week, twice a week, or on a daily basis. NOTE: A healthy frog will continuously shed skin. If you choose to incorporate a filtering system, you should plan to frequently change most filters because of this.
Food: Feed at a quiet time of the day when the animals are calm. Avoid disturbing them before or after. The frogs will either ignore the food in the first instance or regurgitate what they've consumed in the latter. We recommend cleaning tanks first thing in the morning and feeding late in the afternoon. The animals can digest their food during the night while they are calm. Animals will not eat if the tank is too dirty. We recommend feeding your colony Nasco's Frog Brittle as a complete, balanced diet. Feed 1 gram/frog, twice a week.
Health: Xenopus are very robust amphibians. Of the few problems that might arise in the lab, most can be linked to stress or water quality. Many of the causative organisms are ubiquitous in standing water, but multiply out of control when water quality declines or the animal's natural defenses are compromised by stress.
Female Xenopus for Oocyte Harvest: It is important to maintain cool temperatures (16º-18º C). Temperatures in the mid-twenties, even for a few hours, can leave the frogs unharmed but their oocyte quality jeopardized. Problems like this can occur in the summer during transit or if temperature controls fail in the lab. Oocytes will have weak membranes and/or spotty demarcations if this happens.
There can be seasonal variations. The animals go through a natural breeding phase around May through June. Hormone levels are higher in the females at this time and you may see fluctuations in the oocytes they produce.
"Old" oocytes can show up in virgin females that have never had an opportunity to lay eggs. To continue quality egg production, mature females should have ovulation induced every four months. Colonies where large numbers of frogs are held for long periods should schedule females through ovulation four to eight weeks prior to use. Seasonal variations in hormone levels and water temperatures will affect when a frog might rebuild stage 5 or 6 oocytes. There will be individual variations from frog to frog.
Ovulation can be induced by a single injection of 500 I.U. of HCG hormone into the dorsal lymph sac. Most frogs will shed eggs within 36 hours of injection.
Instructions for feeding Xenopus frogs
Please contact us for further information or to place your order.
Eve Swenson, Live Biologicals Manager
Debra Tipton, Biology Operations Manager
PHONE: 1.920.568.5565 (for information)
PHONE: 1.800.558.9595 (to place an order)
FAX: 1.920.568.5573 E-mail: biology@eNasco.com