Diabetes in rabbits

 

 

Esther van Praag, Ph.D.

 

 

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Diabetes is caused by a dysfunction of the pancreas, an endocrine organ that possesses islets of Langerhans. Those islets secrete insulin in the blood circulatory system in order to control the glucose level in the blood and stimulate absorption of glucose into cells. In experiments where the pancreas of rabbits was ligated, a strong decrease of insulin secretion (hypoinsulinemia) was observed, accompanied by an increase of glucagon (hyperglucagonemia). As a consequence the glucose level in the blood increased considerably.

DW ductus, V pylorus, Vf, gall bladder with ductus) from: “Das Kaninchen”, by Dr. U. Gerhardt, 1909

 

Pancreas of the rabbit

In human medicine, there are several types of diabetes:

·        Type 1 diabetes (also known as insulin-dependent or juvenile-onset diabetes) is a condition that is characterized by the destruction of the islets of Langerhans. The underlying cause remains under speculation, including autoimmune, viral, or a combination of both, with the latter resulting in an autoimmune reaction against the virus and the cells of the islets due to mimicry of surface proteins. Individuals diagnosed with diabetes type 1 require regular insulin injections.

·        Type 2 diabetes is primarily observed in obese individuals. Initially, insulin production remains within normal parameters; however, cells develop a mechanism of resistance to the hormone, resulting in a failure to respond. As a result, the level of sugar in the blood remains elevated. Individuals diagnosed with type 2 diabetes require medication to manage their condition, aiming to reduce blood glucose levels.

True diabetes is a very rare to inexistant condition in rabbits, and there is limited information about it in the literature. The exception is obese rabbits and experimentally drug-induced diabetes (e.g., alloxan or streptozotin induced diabetes). Type 1 and type 2 have both been observed. Type 2 symptoms are more prevalent in obese rabbits.

During the onset phase of the disease, rabbits are able to compensate for the lack of insulin production in the pancreas. It was determined that insulin may play a less significant role in rabbits and herbivores' sugar metabolism than in carnivores' metabolism. Many plants have indeed hypoglycemic properties and, when ingested, may help the rabbit adjust its glucose level. A well-balanced diet, comprising a wide variety of fresh vegetables and hay, can effectively manage true diabetes or symptoms similar to diabetes in rabbits, eliminating the need for daily insulin injections. It is imperative to note that rabbits should never receive injections of insulin, as this can be detrimental to their health and even lead to fatal consequences. 

Clinical signs

In cases of experimentally induced diabetes, the presence of hyperglycemia is often accompanied by symptoms such as polydipsia (excessive thirst), polyuria (excessive urination), and polyphagia (strong desire to eat).

Pathology

In rabbits of the New Zealand breed afflicted with type 1 diabetes, endocrine cells of the Langerhans islets were compromised, and hypergranulation was detected, contrasting with the healthy, non-diabetic rabbit population. In other animals, degranulation is typically observed. The lack of insulin production was accompanied by glycosylation of the hemoglobin (attachment of glucose molecules to hemoglobin, the protein responsible for oxygen transport in red blood cells). Untreated diabetes can lead to a range of health complications in rabbits, including mineralization of the kidneys, eye problems, and blood vessel issues. These effects can occur even with a corrected diet.

Medirabbit

Obese rabbits are more prone to develop diabetes-like symptoms

Diagnosis

During a veterinary examination, manipulation of the rabbit can lead to an increase in blood glucose levels to 8.6 mmol/L and higher, resulting in an inaccurate representation of the actual level. This phenomenon is triggered by the release of adrenaline (epinephrine), a molecule that counteracts the effect of insulin and enables a rise in the blood glucose. Knudtzon J. has documented this phenomenon in his research on diabetes in rabbits.

Consequently, diabetes cannot be diagnosed with a single blood test; a series of blood and urine tests must be conducted over time to confirm the diagnosis.

Blood chemistry tests should include:

- blood glucose;

- serum osmolarity;

- elevated BUN;

- electrolytes disbalance (sodium and potassium);

- glucose in urine;

- glycosylation of protein (fructosamine test);

- glycosylated hemoglobin (HbAc1).

Hyperglycemia (excess glucose in the blood) has also been linked to stasis, which often has a poor prognosis for rabbits. This appears to relate to fatty degeneration of the liver. If the rabbit survives, its glucose level, which can reach up to 25 mmol/L, will return to normal.

Differential

Diabetes must be differentiated from:

•         endocrine disorders, e.g. overproduction of cortisol or glucagon, Cushing disease;

•         disorders of the target organs (liver, fat tissue, muscle);

•         pancreatitis (inflammation of the pancreas);

•         renal glycosuria.

Treatment

The treatment of choice a healthy diet:

•         hay;

•         fresh vegetables;

•         good quality pellets;

•         no "junk" food, treats, rich in carbohydrates.

If the rabbit is overweight, a weight-reduction plan must be implemented. This process should be conducted gradually, over a period of weeks, as opposed to days. It is imperative to note that insulin injections should never be administered to a rabbit diagnosed with "diabetes." Compared to dogs and cats, they enjoy a healthier lifestyle with a healthy diet and no insulin injections.

Further Information

Catala J, Daumas M, Chanh AP, Lasserre B, Hollande E. Insulin and glucagon impairments in relation with islet cells morphological modifications following long term pancreatic duct ligation in the rabbit--a model of non-insulin-dependent diabetes. Int J Exp Diabetes Res. 2001; 2(2):101-12.

Conaway HH, Faas FH, Smith SD, Sanders LL. Spontaneous diabetes mellitus in the New Zealand white rabbit: physiologic characteristics. Metabolism. 1981; 30(1):50-6.

Roman-Ramos R, Flores-Saenz JL, Alarcon-Aguilar FJ. Anti-hyperglycemic effect of some edible plants. J Ethnopharmacol 1995; 48(1):25-32

Roth SI, Conaway HH, Sanders LL, Casali RE, Boyd AE 3rd. Spontaneous diabetes mellitus in the New Zealand white rabbit: preliminary morphologic characterization. Lab Invest. 1980; 42(5):571-9.

 

  

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