<em>By Dawn Stone, Animal Keeper, Jason Wark, PhD Candidate and Research Assistant, and Dr. Pam Dennis, Veterinary Epidemiologist
Cleveland Metroparks Zoo, Cleveland, OH</em>

<strong>Introduction</strong>

Golden-bellied mangabeys are an Old World monkey species that has not been studied in the field.  Very limited documentation can be found on this endearing primate.  The captive population in the United States consists of 16 animals (7.9) in five institutions, and a mere 45 worldwide.

Cleveland Metroparks Zoo has a female golden-bellied mangabey, Janet Lee, who has been diagnosed with diabetes.  In the past, the zoo has also housed another diabetic female, the mother of our current male (Brandon).  Upon acquiring Janet Lee and diagnosing the diabetes, it has been Cleveland Metroparks Zoo’s goal to manage the disease through training, medication, and diet.

<strong>Overview of Diabetes</strong>

Diabetes mellitus is a disease characterized by abnormal insulin production or utilization, ultimately leading to increased blood glucose levels. In humans, diabetes is categorized as type 1 or type 2, depending on the production or utilization of insulin.  Type 1 diabetes is when the body does not produce insulin, a hormone needed to convert sugar, starches and other food into energy.  Type 2 diabetes is when the body does not produce enough insulin or the cells ignore the insulin.

Insulin is necessary for the body to be able to use glucose for energy.  When food is consumed the body breaks down all of the sugars and starches into glucose.  Insulin transports glucose from the blood into the cells.  When glucose builds up in the blood instead of going into cells it can lead to diabetic complications (American Diabetes Association). When glucose in the blood reaches a high enough concentration, the kidneys can no longer reabsorb all of it, and it spills over into the urine.

<strong>Janet Lee</strong>

Janet Lee arrived at Cleveland Metroparks Zoo (CMZ) on 9 October 2007.  She was brought to the zoo as a companion for its lone male golden-bellied mangabey and was quarantined in our hospital area. Janet Lee had been diagnosed with diabetes during her pre-shipment exam at the sending institution, but given the few available animals for pairing with Cleveland’s lone male, CMZ agreed to accept the animal with this medical condition. Three days after arrival, hospital keepers submitted a urine sample that showed high ketone and glucose levels. Ketones in the urine (ketonuria) is a condition seen when the body produces excess ketones as an alternative source of energy. Ketones are produced when the body starts breaking down fats instead of sugars for energy. Production of ketones is a normal response to a shortage of glucose, meant to provide an alternate source of fuel from fatty acids. Ketonuria can occur during unregulated diabetes mellitus.

Veterinarians at Cleveland Metroparks Zoo initially attempted to manage Janet Lee’s diabetes with oral medication. She was given Metformin® (125mg orally twice daily) and Glipizide (5 mg orally once daily). Glipizide stimulates the release of insulin from the pancreas. Metformin® has three functions: it slows absorption of sugar from the small intestine, it reduces the rate of glucose production by the liver (gluconeogenesis), and it enhances the sensitivity of cells to insulin. During this time, the only diagnostic test we could do to monitor her glucose was through urine tests. Janet Lee consistently had glucose in her urine, suggesting that the oral anti-diabetic medications were not working adequately to manage her diabetes.

Hospital keepers, along with veterinary technicians, began attempting injections on 27 November  2007.  They first began with an injection of 1 IU of saline that she accepted in her right hip.  The following day she received her first dose of insulin (Protamine Zinc insulin 4 IU IM once daily). Insulin injections were started despite the lack of sufficient behavioral training because oral anti-hyperglycemic medications were not working, and the presence of ketones in her urine caused concern of possible diabetic ketoacidosis. Diabetic ketoacidosis is a potentially life-threatening condition in which the lack of insulin results in metabolism of fats to ketones, metabolic acidosis, dehydration, and electrolyte imbalances.

Insulin injections were stopped on 13 December 2007 due to unreliability in giving the insulin injection.  The hospital keepers and veterinary technicians continued working with Janet Lee with the help of a training consultant to strengthen the behavior.

<strong>Glucometer</strong>

Initial blood glucose readings were done using an Alpha-TRAK® glucometer (Abbott Laboratories).  This glucometer was specifically designed for veterinary use with domestic cats and dogs.  The Alpha-TRAK® glucometer was giving inconsistent readings, so we switched to a Freestyle® glucometer (Abbott Laboratories).  The Freestyle® glucometer was designed for use with humans and provided more consistent blood glucose levels as compared to the Alpha-TRAK® glucometer.

<strong>Training for Insulin Injections</strong>

The ability of having Janet Lee receive insulin injections and voluntary glucose checks was imperative and operant conditioning was used in training the behaviors.  Janet Lee came to Cleveland with training but keepers still started with basics and established a bridge using a whistle.  The whistle is the bridge of choice with new behaviors for these keepers.  With the whistle, behaviors seem to be easily shaped because of the consistency and sharpness of the bridge.

The behaviors of hip and shoulder presentation to the caging were shaped while a capped syringe was in sight.  The insulin, protamine zinc was to be given as an intramuscular injection in the muscles of the hip.  Shoulder was trained as well so that multiple areas would be available if needed.  Keepers were doing five short sessions a day beginning 24 February 2008 and the behaviors took a few short days to shape.  It is when keepers picked up the syringe that Janet Lee would pull away from caging and not have her body completely against the wire.  The act of injecting Janet Lee previously when the behavior was not solid caused some set back in the current training.

It took about a week before she let us put a capped insulin syringe up to her.  Keepers decided to work this behavior as slowly as she needed with the cap on the syringe.  Over time the cap was cut back to expose a very small portion of the needle instead of taking the cap off entirely.  Initially the needle was rubbed across her skin.  This caused her to back away at first but when she did hold for the needle touching her she was jackpotted with sugar-free candy.

Over time, the needle was exposed more by cutting the cap back gradually and instead of just touching her with the needle, keepers would poke her with the needle.  This did cause a little regression at first but because of the amount and consistency of sessions it lasted only a day or two.

On 3 April 2008 Janet Lee began receiving 1 unit of saline IM in her hip in preparation of insulin injection.  By 11 April 2008 keepers were injecting four units of saline BID and on the 12th tested her blood glucose with an Alpha-Trak® reader that read HI and did not register.

The first dose of insulin was given on 13 April 2008.  She received two units of protamine zinc (PZI) IM in her right hip.  Blood glucose was taken prior to injection and read 407 mg/dl.  The behavior of getting blood glucose samples from her toes was not trained in the formal sense of the word. All of the training emphasis had been placed on training for insulin injections, and only when we realized that insulin injections were truly about to happen did we fully appreciate the need for blood glucose monitoring. As this was our first case of treating diabetes with insulin injections, the veterinarians were wary of treating without any ability to monitor blood glucose, so insisted that blood glucose monitoring behaviors become incorporated into the training protocol. Keepers had been working the behavior of hand and foot presentation through caging but had never incorporated the testing instruments until the day of the first insulin injection. Fortunately Janet Lee was a willing participant in the training, and the behavior was readily shaped to facilitate routine blood glucose monitoring.  In hindsight, we appreciate the importance of detailed communication of expectations and maintenance of open lines of communication between veterinary staff and keeper staff in cases requiring intensive clinical management.

<strong>Diet</strong>

The diet from her sending institution was Mazuri® Primate Maintenance Biscuit (70g), endive (180 g), carrot (35 g), yam (35 g), yellow corn (18.5 g), green peas (18.5 g), apple (35 g), red or green grapes (35 g) and banana (35g).   To decrease the amount of simple sugars, the diet was changed to Marion® Leaf Eater Biscuits (200g) Hi-Maize Resistant Starch (125g), green beans (80 g), broccoli (80g), summer squash (80g), sunflower seed kernels (56g), and endive (680g). The Mazuri® biscuit and Hi-Maize resistant starch combination was a biscuit available at the zoo as part of an ongoing study examining the effects of increased dietary fiber on gorilla (Gorilla gorilla) health. The biscuit was chosen for Janet Lee as a means of increasing the dietary fiber in her diet as well as providing resistant starch. Resistant starch is a starch that is not digested in the stomach but is fermented by bacteria in the large colon, providing nutrition without increasing blood glucose levels.

In June 2008, her diet was adjusted to remove the Marion® Leaf Eater Biscuits to further reduce the amount of sugar in her diet. The diet was changed to canned black beans, no salt added (200g), Hi-Maize resistant starch (125 g), green beans (80g), broccoli (80g), summer squash (80g), sunflower seed kernels (30g), endive (340g ), chia seeds (28g) and vitamin D (400IU). Chia seeds were added to the diet as they have been shown in humans to help regulate blood glucose levels.

In December 2008, Janet Lee was included in a diet study examining the behavioral effects of dietary konjac and fenugreek used to ameliorate diabetes in our golden-bellied mangabey and Hamadryas baboons (Papio hamadryas).  We hypothesized that the addition of fenugreek and konjac to the diet of the diabetic animals will ameliorate the hyperglycemia, resulting in increased activity levels more closely resembling the activity levels of the clinically normal animals. Monitoring activity levels of the animals prior to and following the addition of konjac and fenugreek to the diet would provide a non-invasive means of assessing the effect of this dietary supplement. Medicinal plants have been used for centuries to treat diseases, and are the basis of many of our modern-day drugs. Fenugreek, a spice commonly used in Indian and Asian cooking, has been shown to have an anti-diabetic effect in dogs, rats, and mice. It also has an anti-hyperglycemic effect in humans with type 1 (insulin dependent) and type 2 (non-insulin dependent) diabetes.1  Konjac-mannan, a fiber derived from the root of the konjac plant (Amorphophallus konjac), has been used for centuries in Asia as a food. More recently, it is used in food processing as a stabilizer and gelling agent. It has a “generally recognized as safe” (GRAS) status in the United States.2 Konjac fiber has been shown to help control hyperglycemia in type 2 diabetes in humans.2  While we did not see significant changes in the behavior of Janet Lee during this study, the dietary supplement did appear to have a stabilizing effect on her blood glucose and the supplement was incorporated into her daily diet.

Diets in the zoo were evaluated in 2009 and in October 2009 this diet was adjusted to account for the fact that the animal consumed less food than was offered. The animal’s current diet is canned black beans, no salt added (50g), Hi-Maize resistant starch (8 g), green beans (65g), broccoli (65g), summer squash (65g), sunflower seed kernels (15g), endive (200g ), chia seeds (6g), fenugreek (4g), konjac (18g),  and vitamin D (400IU).

<strong>Birth Control</strong>

During the quarantine health exam she was implanted with a birth control implant of melengestrol acetate intramuscularly in the left shoulder.  MGA (melengestrol acetate) implants are a common birth control in primates and implants can function for up to two years. MGA is a synthetic progestin, and side effects of its use can include weight gain. MGA implant was selected based on its proven success as a contraceptive in primates including mangabeys. Following the quarantine period, Janet Lee was housed in an enclosure adjacent to the male mangabey until her diabetes could be managed, at which time she would be housed with the male.

Once Janet Lee was consistently receiving insulin injections, it was still challenging to regulate her blood glucose at levels within the range of 200-250mg/dl. One consideration was that the MGA implant was interfering with normal insulin regulation. As Janet Lee was not currently housed with the male, it was decided that the MGA implant would be removed to eliminate any adverse effects of the implant on diabetes management. Janet Lee went through multiple estrus cycles, and it did appear that the implant may have had adverse effects on her diabetes management. Determining this…

<strong><em><span>Want to read the rest of this article?  For this and many more fascinating articles every month, see Animal Keepers’ Forum.  AKF is available only by being a member of AAZK. </span><a href="http://aecetia.net/gws/aazk/join/">JOIN NOW!</a></em></strong>