Royal Canin Nutritional Information

Royal Canin Nutritional Information

The small breeds (Shih Tzu, Yorkshire Terrier, Miniature Schnauzer, Pekingese) are among the breeds of dog at most risk of urolithiasis. (© Psaila/Lanceau).

Key Points to Remember:

The Role of Nutrition in the Treatment and Prevention of Canine Urolithiasis

Stimulation of Water Intake and Diuresis

For all stone types, encouraging the dog to drink to promote the production of dilute urine is an essential part of preventing stone formation. Diluting the urine limits the concentration of the crystal precursors in the urine. There are three simple ways to encourage water intake: selecting a wet food, hydrating dry food before serving, and slightly increasing the food’s sodium content. A dietary sodium content of 3.2 g /1000 kcal does not have any effect on blood pressure in a healthy dog or a dog with moderate renal pathology.

Urinary pH

Acidifying the urine is the best method to lower urinary struvite saturation and therefore to prevent this type of urinary stone. Struvite stones are highly soluble in acid pH, so acidification will even help to dissolve the stones.

Calcium oxalate stones are not sensitive to urinary pH. Urinary alkalinization indirectly limits the presence of precursors in the urine (by limiting the calciuria and promoting the excretion of citrate, which forms a soluble salt with calcium), but at the same time it increases the risk of struvite formation. It is preferable to combine increased diuresis with a moderate pH (6 - 6.5) to simultaneously prevent the appearance of both oxalate and struvite stones.

Conversely, for both cystine and urate urolithiasis it is necessary to achieve a more alkaline pH (around 7) to increase the solubility of these stones. However, alkalinizing the urine further increases the risk of secondary calcium phosphate urolithiasis.

Proteins

Protein restriction has been recommended to help manage both urate and cystine urolithiasis. In particular, dogs predisposed to urate stones (Dalmatians, English Bulldogs) need a diet that is low in purines, without necessarily reducing the overall protein ingested. These two goals are compatible when a protein source that is low in purine content is selected.

If protein restriction is implemented to assist the management of cystine stones, the diet should be supplemented with taurine and Lcarnitine to help prevent the risk of dilated cardiomyopathy.

Focus on: Sodium

After calcium and potassium, sodium is the most abundant ion in the organism. It represents around 0.13% of the body weight of a mammal. Extracellular sodium is found in the skeleton (43% of total sodium), the interstitial fluid (29%) and the plasma (12%). The remaining body sodium is located intracellularly.

Sodium plays several essential roles in the function of the cell:

• It maintains the balance in osmotic pressure between the intra- and extra-cellular environments thus regulating the volume of extra-cellular fluids. This function of water balance regulation gives sodium an important role in the sense of hunger and micturition.
• It is involved in acid base balance
• It participates in nerve transmission

The digestive absorption of sodium is very important. The maintenance of a constant sodium level in the organism is based on regulation of both renal and intestinal excretion. Dogs do not sweat, hence they are not at risk of excessive sodium loss.

What Is the Sodium Content in the Various Sodium Salts?

• Sodium chloride (NaCl) contains 39% sodium.
  1% sodium in a food therefore corresponds to approximately: 1 / 0.39 = 2.5% NaCl.
• Sodium carbonate contains 37% sodium.
• Sodium bicarbonate contains 27% sodium.

1. Is Blood Pressure Affected by High Dietary Salt Content?

In dogs, increasing the sodium content in the food has a clear role in stimulating diuresis and lowering the urinary calcium oxalate saturation. The relationship between the salt content in human food and hypertension is a subject of intense debate, hence the question of the influence of salt (NaCl) on canine blood pressure is a logical one to ask.

Vienna University in association with Royal Canin studied the development of blood pressure based on the dietary NaCl content (Biourge et al., 2002).

Eight healthy female Beagles age 2 to 4 years were divided into two groups and fed for two weeks with the same dry (acidified) food. The only difference between the two diets was the NaCl content:

• The control diet contained: 0.38% Na and 1.40% Cl
• The NaCl-enriched diet contained: 0.96% Na and 2.40% Cl (DMB).

The two groups consumed the two formulations in turn, with a one-week transition period during which they were fed a standard maintenance food.

The results of this study clearly demonstrated that moderate enrichment of NaCl in the diet increased urine volume (p < 0.001) but did not alter blood pressure of healthy dogs when compared with a standard food. The blood pressure values observed are within the normal reference range (<160 mm Hg).

Four other studies have also failed to provide any evidence that moderate increases in dietary sodium (up to 3.2 g Na/1000 kcal) influences the blood pressure of dogs and cats, be they healthy or moderate renal disease patients (Burankarl et al., 2003; Greco et al., 1994; Kirk 2002; Luckschander et al., 2002).

The National Research Council Committee on Animal Nutrition (NRC) has been tasked with establishing nutritional requirements for the dog and cat by the U.S. Academy of Sciences. Their latest recommendations indicate that there is no adverse health risk for the dog when the sodium content of the diet contains 3.75 g /1000 kcal in a dry food providing 4000 kcal/kg. This is equivalent to a sodium content of 1.5%.

2. Determination of the Relative Supersaturation of Canine Urine