Royal Canin Nutritional Information

16. Royal Canin Nutritional Information

Focus on: Arginine

For cats, arginine is an essential amino acid used in the synthesis of many proteins. It also plays a role in essential functions:

• As a mandatory intermediary in the synthesis of urea
• As a precursor in the synthesis of nitric oxide and biogenic amines
• As a stimulator of secretion of several hormones, such as insulin, glucagon and gastrin.

Consequences of Arginine Deficiency

While a kitten’s growth obviously depends on adequate intake of arginine through the food, it should not be forgotten that adult cats are extremely sensitive to even a shortterm deficiency of arginine. When it receives a food that contains a high amino acid content but no arginine, signs of ammonia intoxication appear within 1 - 3 hours: ptyalism, vomiting, ataxia, hyperesthesia and nervous problems (Morris and Rogers, 1978). In some conditions, the intoxication can be lethal.

The cat’s strong dependence on arginine can be explained by its excellent adaptation to a carnivorous diet. Arginine is abundant in animal protein. On the other hand, while ornithine and citrulline are possible arginine precursors in other mammals, the conversion rate is too low in cats to cover arginine requirements.

Figure 28. Synthesis of urea.

Recommended Arginine Intakes in Cats

For adult cats, the NRC (2006) recommends an intake of < 0.77 % DM (ME is around 4,000 kcal/kg) or 1.93 g/1000 kcal. The arginine should be raised in proportion to the protein content (+ 0.02 g of arginine by g of protein above the minimum level of 20%).

Arginine, a Promoter of Insulin Secretion

In cats, amino acids and especially arginine greatly stimulate the secretion of insulin by the pancreas (Curry et al, 1982). Arginine acts by producing direct depolarization of the membranes of the ß cells in the pancreas and induces a flow of calcium ions.

This secretion of insulin is also stimulated in the presence of glucotoxicity. In the event of chronic hyperglycemia, the secretion of insulin in response to arginine is normal or increased, while the secretion of insulin in response to glucose is decreased (Kitamura et al, 1999).

These observations may explain the benefit of very high protein diets for diabetic cats. A high arginine diet (>7 g/1000 kcal) helps stimulate insulin secretion and promotes the remission of the disease.

Diabetes mellitus is most often observed in mature cats, peaking around 10 - 12 years. (© C. Hermeline/Diffomédia (Burmese)).

Risk Factors for Diabetes Mellitus in Cats

Endocrine diseases are increasingly the new frontier of feline medicine. Together with hyperthyroidism, diabetes mellitus is one of the most common endocrinopathies in cats. For the last few years, the number of obese subjects in the cat population has been on the increase, as has the incidence of diabetes mellitus.

Obesity

This is the principle risk factor. It is responsible for the reduction in peripheral sensitivity to insulin. Compensatory hyperinsulinemia can then lead to the exhaustion of β cells in the pancreas.

Age

The disease is most common in mature individuals with insulin resistance (error in the peripheral action of insulin) and insufficient insulin secretion. A peak is observed around 10 - 12 years.

Sex

Males appear to be at greater risk of diabetes (in association with obesity).

Drugs

Glucocorticoids and synthesized progestagens reduce insulin sensitivity.

Endocrine disease

E.g., acromegaly and hyperadrenocorticism, which are uncommon in cats.

Clinical Signs

Diabetes mellitus is a heterogeneous disease characterized by pronounced hyperglycemia following an insulin secretion and/or action anomaly. By analogy with observations in humans, most cats appear to suffer from type 2 diabetes.

The most common symptoms observed by owners are:

• Polydipsia
• Weight loss over several weeks
• Anorexia
• Fatigue, lethargy
• Vomiting
• Polyphagia

Poor personal hygiene and locomotor problems (e.g., difficulty jumping) may sometimes cause owners to consult a veterinarian. All these signs are often mild and develop very slowly.

Figure 29. Decision-making algorithm when diabetes mellitus is suspected in a cat. (Dr. Dominique Péchereau). Chronic hyperglycemia results in a marked drop in the secretion of insulin. The normalization of glycemia during treatment helps restore this secretion in certain individuals. This is sometimes all that is needed to ensure glycemic balance, hence the notion of “transitory diabetes”. Twenty to fifty per cent of cats present a "remission" of diabetes between 1 and 4 months after the start of the treatment. For this reason, and with a view to sparing the pancreatic function as far as possible, insulin is the preferred initial treatment.

Figure 30.

Frequency of Insulin Therapy

Give preference to two daily insulin injections, while checking the activity of the selected insulin.

• Never start with more than 0.5 U/kg, twice per day (at least the first two weeks).
• Always make sure the owner is properly instructed to ensure the efficacy of the treatment. Practice the injection, emphasize the necessity of consistency with the dose, draw attention to the injection site and signs to be monitored (especially those connected to hypoglycemia).

Treatment Follow-up

Blood Glucose Concentration

Owners should monitor the blood glucose concentration using a "glucometer". The aim is to maintain the blood glucose between 120 and 160 mg/dl (6.66 and 8.88 mmol/L). If it falls below 120 mg/dl (6.66 mmol/L), the insulin dose should be reduced.

Monitor Water Consumption

Monitoring water consumption is a very reliable parameter for indicating the degree of glycemic control.

Regularly Check Glucosuria

It is important that owners know how to use and interpret a urine strip test. The renal glucose threshold in cats is between 200 and 270 mg/dl (11.1 and 14.99 mmol/L) of glycemia. Regularly monitoring the urine for glucosuria will provide an indication of when to reduce the insulin dose in cases of transient diabetes mellitus. If the glucosuria remains negative over several consecutive samples, the insulin dose maybe reduced.

Measurement of Fructosamine and Glycosylated Hemoglobin

The analysis of these parameters simplifies the control by the owner. Fructosamine must be kept below 500 μmol/L and glycosylated hemoglobin below 3%.

Dietary Rules

Control Excess Weight

Obesity is a major risk factor with respect to insulin resistance, so it is vital to select a food with a moderate energy and fat content, and a high protein content to promote an ideal body condition and maintain the lean mass. The supplementation of L-carnitine is also recommended to facilitate the use of fatty acids and so weight loss.

Minimize Stimulation of Β Cells by Glucose

High protein diets (> 45 % of dry matter (DM)) with a moderate starch content (< 20% DM) from a source with a low glycemic index helps limit post-prandial hyperglycemia peaks. These types of diet combat insulin resistance. The presence of psyllium, a soluble fiber that slows down gastric emptying and regulates digestive transit, also helps slow down glucose assimilation.

Stimulate Endogenous Secretion of Insulin

Several amino acids, especially arginine, promote endogenous secretion of insulin in cats. This is an additional argument in favor of using high protein diets in the event of diabetes mellitus in cats.

By following the nutritional rules, you can reduce the insulin dose or even achieve remission of the disease.