13a Nutrition of Fish, Birds, Reptiles

Question 1

Aquarium fish as pets.

Answer 1

• > 5000 species kept in aquariums
• no detailed info about nutrient requirements
• extrapolation of data from aquaculture
• no need for so many different feeds
• examples: koi carp, coral butterfly
• few carnivorous, many omnivorous, many herbivorous
• major classifications: warm or cold temp, top bottom or middle feeding, night or day feeding, single or mixed population

Question 2

Describe digestive physiology of fish.

Answer 2

• only few have teeth
• food eaten whole or in large particles
• stomach small (large in omnivores or herbivores)
• in small fish, no stomach and food passes directly to intestines (bite size is swallow size)
• pancreatic duct enters at proximal end of intestine where stomach would be

Question 3

Describe energy requirements of fish.

Answer 3

• ectothermic fish do not maintain a constant body temperature ‘cold blooded’
• live and carry out chemical reactions at the whim of the environmental temperature they live in
• major survival benefit -> require less energy to maintain normal life
• energy need is direct correlate of water temp

Question 4

Describe nutrient requirements of fish

Answer 4

• rely more on amino acids than carbs
• higher protein turnover than mammals
• omnivorous and carnivorous fish can utilize starch (better in gelatinized form)
• herbivorous fish not adapted to large meals (3-4 small meals better)

Question 5

Describe some special nutrient requirements of fish.

Answer 5

• do not need as much Ca and P as don’t have hard bones. uptake and excretion regulated through gills
• high amounts of iron can interfere in oxygen transfer
• can cope with a range of mineral concentrations (sodium, potassium, chloride)
• water soluble vitamins quickly dissolved in water so feed often over supplemented
• vit C essential; deficiency leads to lordosis
• pigmentation due to carotenoids (astaxanthin and canthaxanthin); beta carotene can not be used by all fish so feed should contain specific carotenoid
• omega 3 and 6 fatty acids needed because of big changes in water temp; linolenic acid need to keep fish membranes fluids even with cool temps; saturated fats will solidify and clog digestive system

Question 6

What are the 2 orders of ornamental birds?

Answer 6

• order Psittaciformes

- order Passeriformes

Question 7

Describe the digestive physiology of birds.

Answer 7

• cecum and colon small or absent
• transit time <12h; budgies and finches 3-6 hours
• small birds suffer from starvation in less than 3 days so food must be available at all times

Question 8

Describe the nutrient requirements of birds.

Answer 8

• main source of glucose: starch from variety of seeds
• many small ornamental birds can not use fibre because no cecum and colon, so do not feed many fresh fruit and veg
• berries, dark green or yellow veg, peas, kidney and pinto beans
• some large psitterines can use fibre as part of diet
• birds can also pick and choose which seeds to meet requirements

Question 9

Describe life cycle feeding management

Answer 9

• growth very rapid
• body size increase ten fold in 10 days
• feather growth requires greater amounts of amino acids: proline, glycine, methionine and cysteine
• uric acid synthesis needs more energy to make than urea (increased energy requirement)
• urea synthesized from glycine and acetic acid so glycine essential amino acid for growing and reproducing birds

Question 10

Describe feeding during moult

Answer 10

• replacement of feathers by new ones
• usually on annual basis in fall
• large amounts of well balanced amino acids especially methionine, cysteine and glycine
• good sources include canola seed and white millet
• overall increased protein and energy requirements

Question 11

Describe general feeding management of birds.

Answer 11

• feed balanced diet
• provide mix of different types of seeds and vegetative parts to meet mineral and vitamin requirements
• birds learn feeding from their parents
• when weaning birds from one diet to another, offer in morning

Question 12

Do we have lots of research on reptiles?

Answer 12

• nutritional research is limited
• dietary recommendations based on knowledge of natural diets and feeding histories, clinical experience and principles of comparative nutrition
• herbivorous, omnivorous and carnivorous

Question 13

How are the GI tracts of omnivorous/ carnivorous and herbivorous reptiles different?

Answer 13

• cecum larger volume and greater relative length of herbivore hind gut

Question 14

Describe reptilian digestion, metabolism and nutrition

Answer 14

• digestive system of herbivorous reptiles different than mammals (numerous fold and partitions to slow down passage and increase fermentation)
• herbivorous reptiles larger than carnivorous (more room for fermentation, habitat and optimal temp range also influence size, carnivorous need to move faster)

Question 15

Describe water requirements of reptiles.

Answer 15

• water delivery must fit environment of animals, proper depth, smell and taste, proper humidity
• dehydration can cause gout or dyscedysis (drying of skin and inability to shed)
• too high humidity can cause hyperkeratinization

Question 16

Describe energy requirement of reptiles

Answer 16

• ectothermic: too low temp causes decrease in food intake; too high temp causes excessive metabolism, decreased food intake and growth
• only require 1/4 of energy of mammals
• inverse relation between metabolic rate and body size

Question 17

Describe protein requirement of reptiles

Answer 17

• carnivorous: 30-60%
• herbivorous: less than that
• high requirements os use animal proteins or high protein seeds and nuts

Question 18

Feeding management of carnivorous reptiles.

Answer 18

• invertebrate prey like worms too low in Ca
• feeding of only meat leads to excess protein and energy and deficiencies in Ca and other nutrients
• wide variety should be fed
• cat food may be option
• aquatic turtles: trout food or other aquaculture food