Lecture 14- Cat nutrition Flashcards
What are the differences in feeding production vs. companion animals?
- feeding mature vs growing animals
- inactive vs production animals
- maintenance vs growth/production + maintenance • can live into old age
What are the requirements of companion and farm animals?
-Companion animals: • mature • inactive • live to old age -Farm animals: • growing • production • live to maturity • ....to end of productive life
What are the specific dietary requirements for cats?
- Cats require dietary - • arachadonic acid
- pre-formed vitamin A • Taurine and felidine
- All are obtained from meat
- Cats = obligate carnivores • Dogs are more omnivore
What are the characteristics of cats?
- adult domestic cat • 2to6kg
- kitten
- rapid growth in first 6 months • to 3/4 of mature size
- Domestic cats remain the least changed domesticated species • Behaviour
- Nutrition etc.
What are cat teeth like?
- specific to being carnivorous
- tear meat
What is cats’ feeding behaviour like?
• Cats are solitary hunters (except lion)
• Domestic cats will search out wild prey (insects, rodents etc) more often when meat is not
included in the diet
• 1 mouse or small bird = 30 kcal
• Thus need 8-12 per day!
• Cats will voluntarily eat 12-20 meals per day
• Cats do not have clear cut circadian rhythms
• Core temperature is not circadian
• Both diurnal & nocturnal
• Some cats do not adapt well to once daily feeding
• Not so in dogs
• Can become ‘fixed’ on one diet type
• Generally select wet over dry foods
What affects the way they like some foods?
- Sugar will not increase the palatability of cat diets • Cats will not eat powdered diets
- Will eat pellets, mash or gels
- Hydrogenated fats (such as coconut oil) that contain medium-chain fatty acids have negative palatability in cats
- As little as 5% can cause avoidance • Not true for dogs
- Cats are more sensitive to bitter tastes than other species
What are metabolism peculiarities in cats?
- Most animals will adjust the activity of enzymes involved in protein digestion to suit protein intake
- Cat’s DO NOT adjust
- Permanently set to ‘high activity’= energy expensive
- BUT cats can conserve nitrogen and adapt protein oxidation to match diet provided their maintenance requirements are met
- Protein turnover rate in cats is slow but requirements are high • Paradox
- Believed to be due to the large brain of the cat demanding that protein > gluconeogenesis > glucose
- High requirement for sulphur containing AA’s • ???
- High requirement for B vitamins
Do cats control feed intake?
- There are reports of cats not regulating body weight • Contentious
- Regulated by palatability & energy loss in urine
- Interestingly, predatory behaviour takes precedence over eating
- Cats will stop eating to kill a rodent then return to their food without eating the rodent
What types of food there are for cats?
- Cat food needs to be processed properly so that the cat can chew it
- Cats lack molar teeth
- Need to incise rather than grind food
- Food needs to be appropriate size/shape
- Dry
- 6-10% water
- Semi-moist
- 15-30% water
- Canned
- 75% water
What is water consumption like for cats?
• Cats can concentrate urine more than dogs or humans • Slow to rehydrate after dehydration (weak thirst)
• Evolution as desert animals? • Can drink saltwater!
-prefer running water
What are the energy requirements of catsM
• maintenance (4 kg)
• adult, active - 335
• adult, inactive - 293
• kitten
• 10 weeks - 1046 (1 kg) • 30 weeks - 484 (3 kg)
-adjust for body size and life stage, when old similar to a kitten
What are the essential amino acids?
- arginine
- histadine • isoleucine • lysine
- leucine
- methionine
- phenylalanine
- threonine
- tryptophan
- valine
- Taurine & felidine
Why the high AA requirement?
-Possible reasons:
• High requirement for one or more EAA
• Higher than normal requirement for N
What is the case with enzyme adaptation in most animals?
- Most mammals have the ability to adapt enzyme activity to protein intake
- Conservation of AA when consuming low-protein diets • Catabolism of AA when consuming high-protein diets • Rat enzyme activity can increase 2.75 to 13.0 fold
What is the enzyme adaptation like normally?
- Ammonia resulting from AA deamination is continually diverted to urea and lost from the body pool
- Cat cannot conserve N from the body pool
- Must consume high levels of protein to maintain body N pool
- Lack of enzymatic adaptation due to carnivorous nature of cats
- High obligatory N loss regardless of protein intake
What is urinary nitrogen excretion in cats?
- Cats excrete 360 mg urinary nitrogen/kg body weight -0.75 per day • Excretion of dogs is 110 mg/kg BW -0.75/d
- Protein utilization in the cat is not efficient
- Cats need excess protein to provide substrate for hepatic enzymes
What is the importance of Arginine?
- Essential amino acid
- Can be synthesized by animals.
- But required for growth in rat, chick, dog.
- NOT required for maintenance of most species. • Exceptions: cat, ferret, dog
What happens to cats if they don’t have Arginine in their diet?
- After fed a single arginine-free meal: • Cats had severe hyperammonemia
- Lethargy
- Emesis
- Hyperglycemia
- Hypersalivation
- Inability to stand
- Rapid weight loss (5-10% BW in 24h)
Why did increased NH3 produce hyperglycemia?
- Increased plasma NH3 leads to:
- Increased glucagon release by pancreas causing: • Decreasedglucoseutilization
- Blood glucose does not respond to insulin
- Seen in other species (humans, rats) with ammonia intoxication
Why such drastic response to NH3?
- Does not occur with other amino acid deficiencies
* Most result in decreased feed intake, weight loss, but take days to weeks for death
What happens when arginine is deficient?
- Less ornithine available to condense with NH3
- NH3 builds up in blood
- In most animals Ornithine synthesized in intestinal mucosa from glutamine and glutamic acid
- Using enzymes, pyrroline-5-carboxylate synthase and ornithine amino transferase
- These enzymes not active
- So, little endogenous ornithine synthesized.
What are the reasons for Arginine requirement in cats?
- Extreme sensitivity to deficiency
* Constitutively high AA catabolism and high NH3 production • Limited capacity to synthesize ornithine
What is taurine?
• Sulphur amino acid
• Not found in plant proteins
• Synthesized from methionine or cysteine
• Limited array of enzymes for conversion of methionine to taurine
-this is why cats have to eat meat!
What is taurine needed for?
- Taurine used in bile acid conjugation
- Cats can only use taurine (taurocholic acid)
- carnivores
- Cats can not conjugate with glycine (glycocholic acid) • Herbivores
- Both found in omnivores
What are some other functions of taurine?
- Retinal function
- Normal myocardial function
- Retina and myocardium contain 300-400x the taurine found in plasma • Necessary for normal reproduction in queens
What happens to cats that are taurine deficiency?
- FCRD – feline central retinal degeneration
- Cats fed low protein/vitamin A deficient diet had retinal and corneal lesions
- Vitamin A corrected corneal lesions
- Taurine deficiency caused retinal lesions
- Taurine deficiency can cause blindness within 9 months
What is the role of taurine in retinal tissue?
- Taurine regulates Ca2+ /K+ flux in retina
- Without taurine,
- Photoreceptors are disrupted/ dysfunctional • Degeneration of retina tissue
- Abnormal electroretinograms at 5-6 months • Blindness at 9-12 months
What else happens when taurine deficient?
- DCM – dialated cardiomyopathy
- Without taurine, decreased myocardial contractivity
- Cardiac failure
- Reversible with taurine re-supplementation
- May play role in Ca2+ /K+ flux in myocardial cells (improves membrane integrity)
What are the practical concerns with Taurine?
- Taurine sources:
- Plant-based feedstuff sources do not contain taurine
- Animal products (meat, poultry, fish) contain 0.1 – 0.2% taurine (DM basis) • Crystalline taurine
What is catnip?
- Nepetacataria
- Native to parts of Europe, Middle East, Central Asia and parts of China
- Naturalized to New Zealand and North America • Looks like mint
- Made into tea, used as a herb, smoked
- Contains feline attractant nepetalactone-hallucinogen
- Causes cats (domestic and others) to “get high” for ~15 mins
- Rubbing on the plant
- Drooling
- Sleeping
- Anxiety
- Purring
- Erratic hyperactive behaviour (leaping)
- Growling, meowing, biting
Summary?
- Cats are obligate carnivores
- No requirement for carbohydrates
- Need to consume most of their water from food • Low drive for drinking water
- Specific requirement for AA’s • Taurine
- Arginine
