Pet Health Guide - Liver

The liver performs many vital functions, which include:

• Secretion of bile necessary for digestion of fats and absorbing fat soluble vitamins.
• Storage of certain minerals and foodstuffs.
• Detoxification of ammonia by-product buildup.
• Metabolism of hormones and drugs.
• Production of certain proteins.
• Protein, fat, and carbohydrate metabolism for conversion into glucose and energy.

These functions are impaired to varying degrees in dogs and cats with liver disease. With liver disease, the liver is especially sensitive to meat proteins and typically results in reduced production of serum proteins and an increase of urinary/blood ammonia from nitrogen waste products.

Clinical Signs

• Poor appetite
• Weight loss
• Excessive drinking (polydipsia) and urination (polyuria) [PU/PD]
• Jaundice
• Abdominal swelling (ascites) primarily in dogs
• Intermittent fever
• Neurobehavioral abnormalities

Liver Disease & Diet Recommendations

Excessive protein intake should be avoided as it is associated with increased production of ammonia and the subsequent occurrence of liver encephalopathy. Poor quality proteins and meat based proteins have been implicated to exacerbate liver disease. If the liver is compromised, the by-products of protein digestion are not removed efficiently or effectively. Toxins begin to accumulate in the body, protein malnutrition resulting in muscle and weight loss occurs, and the normal response of overcompensating by feeding extra protein results in increased ammonia production and further advancement of liver disease. This is why a sufficient amount of protein is necessary to maintain lean body mass and protein synthesis.

Protein amounts should be limited to 15% dry matter (maximum) for dogs and 20% dry matter for cats with liver disease. This moderate reduction in protein intake, and substituting alternative vegetable proteins (containing lower amounts of nitrogen waste products) is recommended to prevent and reduce the clinical signs of liver disease and muscle wasting.

Dietary fat and carbohydrates are often needed in elevated amounts to minimize muscle wasting and compensate for feeding lower protein levels. Complex carbohydrates (starch & fiber) slows the rate of digestion in the small intestine which allows for more thorough digestion of food and the slower release of nutrients into the bloodstream. Fiber, therefore, maintains an even and continuous flow of nourishment without the spikes in hunger often seen without it.

Similarly, oats products (oatmeal) also have a regulatory capacity on the liver’s production of glucose thereby maintaining more consistent energy levels through the controlled release of glucose into the circulation. Carbohydrates help reduce fluctuations of blood glucose concentrations preventing secondary type II diabetes in animals.

Dogs

Feeding Plan Considerations

Daily feedings should be divided into 2-4 meals to help maximize energy intake, regulate digestion and improve protein and glucose tolerances. Individual requirement s may vary so consult your primary care veterinarian.

1. Vegetable and dairy proteins such as soy, peanuts and cheese are preferred over meat protein sources ~18%-22%. Vegetarian diets are optimal. Protein restrictions are limited to less than 18% in dogs suffering from potential liver encephalopathy's.
2. Fat restriction is not a major consideration unless malabsorption is occurring.
3. Complex carbohydrates (pasta, brown rice) should comprise ~20%-40% of the diet in order to provide the bulk of energy requirements.
4. A higher fiber diet ~10%-20% helps eliminated ammonia through fermentation in the colon. Higher fiber diets are difficult to maintain caloric requirements and body condition and should not be used in debilitated liver patients.
5. Psyllium and oat bran traps ammonia in the colon to reduce potential neuronal encephalopathy's.
6. Zinc acetate, zinc sulfate or zinc methionine (Pala-Z) can be given at 1-1.5 mg/lb/day.

Cats

Feeding Plan Considerations

Daily feedings should be divided into 4-6 meals to help maximize energy intake, regulate digestion and improve protein and glucose tolerances. Individual requirement s may vary so consult your primary care veterinarian.

1. Proteins from foods such as shellfish, fish meal, spleen, liver etc. should be restricted because these foods increase uric acid precursors which require increased liver function. Reduced protein levels at ~2.27 g/lb should be fed.
2. Dietary fat levels ~10%-20% are recommended in order to provide sufficient energy. Fat restriction is not a major consideration unless malabsorption or lipidosis (fatty liver disease) is occurring.
3. Complex carbohydrates (pasta, brown rice) should comprise ~20%-40% of the diet in order to provide the bulk of energy requirements.
4. A higher fiber diet ~10%-20% helps eliminated ammonia through fermentation in the colon. Higher fiber diets are difficult to maintain caloric requirements and body condition and should not be used in debilitated liver patients.
5. Zinc acetate, zinc sulfate or zinc methionine (Pala-Z) can be given at 1-1.5 mg/lb/day.
6. Restricted salt (sodium) intake ~240 mg is recommended if edema or swelling is present.

Feeding Plan Considerations - Liver Encephalopathy (Increased Blood Ammonia Levels)

1. Proteins from foods such as shellfish, fish meal, spleen, liver etc. should be restricted because these foods increase uric acid precursors which require increased liver function. Protein levels should be restricted to ~1.36-1.82 g/lb.
2. Psyllium and oat bran traps ammonia in the colon to reduce blood ammonia levels.
3. The amino acid arginine is often needed above and beyond that included in a balanced diet, ~250-500 mg twice per day.
4. Dietary fat levels ~10%-20% are recommended in order to provide sufficient energy. Fat restriction is not a major consideration unless malabsorption or lipidosis (fatty liver disease) is occurring.
5. Complex carbohydrates (pasta, brown rice) should comprise ~20%-40% of the diet in order to provide the bulk of energy requirements.
6. Zinc acetate, zinc sulfate or zinc methionine (Pala-Z) should be given at 1-1.5 mg/lb/day.
7. Restricted salt (sodium) intake ~240 mg is recommended if edema or swelling is present.

Feeding Plan Considerations - Liver Lipidosis (Fatty Liver Disease)

1. Proteins from foods such as shellfish, fish meal, spleen, liver etc. should be restricted because these foods increase uric acid precursors which require increased liver function. Protein levels should be restricted to ~1.36-1.82 g/lb.
2. Reduce dietary fat levels ~10% in order to provide sufficient energy. Fat restriction is a major consideration with fatty liver disease.
3. Complex carbohydrates (pasta, brown rice) should comprise ~20%-40% of the diet in order to provide the bulk of energy requirements.
4. Zinc acetate, zinc sulfate or zinc methionine (Pala-Z) should be given at 1-1.5 mg/lb/day.
5. Restricted salt (sodium) intake ~240 mg is recommended if edema or swelling is present.
6. Carnitine ~250-500 mg/day; choline ~10-15 mg/lb/day; arginine ~250-500 mg/twice per day; vitamin B-12 have all benefited cats with fatty liver disease.

Note: The veterinary prescription food formulations and their ingredients are specific for liver disease dogs. Potential allergic ingredients (wheat, corn, soy) if included, are discount in lieu of the benefits afforded by this diet.

Dog & Cat Supplements

Zinc (a stomach irritant to some dogs) is an important cofactor involved in the detoxification and removal of ammonia and copper which often accumulates in animals with liver disease. Certain breeds of dogs, like the Doberman Pincher, West Highland White Terrier and Bedlington Terrier, have genetically related liver disease or copper storage disease which causes liver dysfunction.

Supplementation with a multi-vitamin containing B-1, B-6 and B-12 are very beneficial to cats and dogs with fatty liver disease. Marin for Dogs, or Marin for Cats is a liver specific supplement that contains zinc and Vitamin E to help reduced copper accumulation, reduce the incidence of liver fibrosis, inflammation and free radical injury. Antiox for Dogs and Antiox for Cats is another antioxidant rich supplement that inhibits free radical cell aging throughout the body but is non-specific for the liver as the other supplements mentioned here.

Denosyl for Dogs and Denosyl for Cats is a liver specific supplement containing SAMe which increases liver glutathione levels. Glutathione is a potent liver antioxidant formed when dogs and cats metabolize SAMe.

New to the market is the supplement Denamarin for Dogs and Denamarin for Cats which combines the ingredients found in Marin and Denosyl. Zinc and Vitamin E are not added to this products, however, it delivers a very specific and beneficial formulation to help protect your pet’s liver.

Canine Prescription Liver Diets

(**) contains beet pulp sugars

Feline Prescription Liver Diets