Feline specific nutrient requirements Flashcards
(9 cards)
What are the implications for the strictly carnivorous status of cats
Cats are strictly carnivorous, which explains their unsual requirement for specific nutrients which cannot be endogenousely synthesized in sufficient amounts to meet their needs:
- arachidonic acid
- vitamins A, D and many B vitamins (particularly niacin)
- taurine
- arginine
Explain why cats are particularly adapted for high protein intake
They have a high, fixed rate of activity of the enzymes of protein degradation and disposal (including aminotransferases and urea cycle enzymes)
- this lack of metabolic flexibility becomes critically important when cats are inappetent, are consuming diets containing poor-quality protein, or are not consuming a suuficient amount of protein in the diet to meet their needs
What are the consequences of prolonged inadequate protein intake
Loss of muscle mass
Abnormal energy metabolism
Reduced or poor immune function
Reduced protein availability for structural repair
Abnormal function of critical metabolic pathways (e.g., glutathione or nitric oxide pathways)
Why taurine is essential in cats
Taurine is essential in cats because they cannot synthesize adequate quantities from the typical precursors (i.e., methionine or cysteine)
- enzymes required for synthesis of taurine are only minimally active in cats
- cats have a constant and obligate loss of taurine into bile, because they conjugate bile acids only with taurine
Requirements for taurine in cats is influenced by:
- the source of protein:
- taurine is found in animal-source proteins but must be supplemented when plant-source proteins are used
- commercial processing (heat processing reduces taurine bioavailability)
- content of sulfur-containing amino acids and amount of dietary fiber (diets high in fiber increase the need for taurine)
What are the most common signs of taurine deficiency
Prolonged (i.e., several months) deficiency of taurine is required before clinical signs appear
The most common signs of deficiency are:
- blindness (central retinal degeneration
- reproductive failure or neonatal loss
- development of dilated cardiomyopathy
Why arginine is an essential amino acid in cats
Because cats are unable to synthesize sufficient amounts of ornithine or citrulline for conversion to arginine
Cats continually use large amounts of arginine in the urea cycle
- because this cycle is not down-regulated in cats during periods of anorexia
- arginine supplements should be considered in anorectic cats
Arginine supplementation must be used to avoid deficiency in cats fed diets with plant-origin protein soources
Why cats have a higher requirement for methionine and cysteine
Methionine and cysteine are glucogenic amino acids in cats that are catabolized to pyruvate and then subsequently oxidized to provide energy
Deficiencies may develop in:
- anorectic cats
- cats fed diets that contain plant-origin proteins
- cats fed enteral formulations for use in humans
What are the physiologic adaptations of cats that reflect their low carbohydrate intake
Cats lack salivary amylase
Cats have low activities of intestinal and pancreatic amylase
Cats have reduced activities of intestinal disaccharidases
Cats have minimal activity of hepatic glycogen synthetase
The liver in cats does not contain fructokinase, an enzyme necessary for metabolism of simple sugars
What would be the consequences of high amounts of carbohydrates in cat’s diets
Decrease protein digestibility
Reduction in fecal pH due to an increased microbial fermentation in the colon and thus an increased production of organic acids
Poorly digestible carbohydrates or an overload of highly digestible carbohydrates may induce considerable digestive adverse effects such as diarrhea, flatulence and bloating
Additional starch in the diet that is not stored as muscle glycogen or used for energy is stored as fat
Cats that consume diets high in simple sugars become hyperglycemic and fructosuric
