I was just about to modify the last post that mentioned that MM...hang on
taken from
http://www.veterinarypracticenews.com/vet-cover-stories/feline-nutrition-in-search-of-top-performance.aspxIndeed, veterinary concerns related to struvite and calcium oxalate uroliths, and the difficulties in managing each, have been recognized by many veterinary diet manufacturers.
Royal Canin Veterinary Diets in St. Charles, Mo., for example, has used the relative supersaturation (RSS) urinalysis technique, adapted from human medicine, as a means of measuring ion saturation in feline urine samples to predict the chance that struvite and calcium oxalate crystals will form.
With such data in hand, the company formulates its Urinary S/O diets to promote a urinary environment unfavorable to the development of both types of crystals.
“Using RSS is a lot more effective than just looking at pH,” says Brent Mayabb, DVM, technical services manager for Royal Canin.
“Veterinarians have had a lot of success managing struvite according to dietary pH, but it isn’t the driving factor with calcium oxalate. So in practice, veterinarians may see cats that constantly go back and forth between stone types. Those cats can be hard to manage medically, especially if the cat is a picky eater.”
These are the uroliths retrieved from the bladder of the cat pictured in the radiograph. They were removed non-surgically using a basket retrieval technique. Quantitative mineral analysis revealed that the stones were composed of 100 percent calcium oxalate monohydrate and the shell was composed of 10 percent calcium oxalate monohydrate and 90 percent calcium oxalate dihydrate. (Courtesy of Jody Lulich, Ph.D., University of Minnesota)
Royal Canin’s diets are formulated on the premise that, although control of urinary pH is effective in dissolving struvite crystals, it can’t be relied on to manage both struvite and calcium oxalate. In this respect, Royal Canin reports that urinary dilution has been shown as an effective way of limiting formation of both struvite and calcium oxalate.
Such dilution is achieved by increasing dietary sodium levels, producing an increase in urine volume.
“Sodium stimulates more drinking,” Dr. Mayabb says. “And that means the cat is urinating more frequently. So precursors to crystal or stone formation are flushed from the body quickly.”
In establishing sodium levels for its diets, Royal Canin refers to independent published studies as an indication that its foods are well within acceptable limits. Although absolute maximum levels of sodium have not been determined in cats, the company points to a 2006 report, National Research Council’s “Nutrient Requirements of Dogs and Cats," which concluded that cats can tolerate a sodium concentration of 15 grams per kilogram per meal, so long as they have access to water.
(i have to say i thought the the above sodium levels to be alarmingly high, this is the acceptable recommended daily amounts for children , i know cats are different and concentrate urine etc much more but even though it shocked me ) ---
The guidance says babies aged up to six months should consume less than one gramme of salt per day.
Older babies aged seven months to one year should consume around one gramme.
Children between one and six should consume no more than two grammes.
And children aged seven to 14 should have a maximum of five grammes.
