L 24 - Bacteria in Digestion

Question 1

What role do bacteria play in digestive function?

Answer 1

*particularly herbivores * foregut and hindgut serve as bacterial fermentation chambers

Question 2

How do bacteria contribute to digestive health?

Answer 2

*Protective role against colonization *Promote enterocyte maturation

Question 3

What 2 crucial roles to bacteria play in the digestive processes?

Answer 3

1. Digestive function 2. Digestive health

Question 4

What are the advantages of microbial digestion in the foregut?

Answer 4

• Large quantities of food can be stored rapidly for later mastication and fermentation • Bacterial cell contents (a source of protein) are released at an early stage in digestion • The main products of fermentation have ample opportunity to be absorbed in the remainder of the tract

Question 5

What are the disadvantages of microbial digestion in the foregut?

Answer 5

• All food constituents are exposed to bacterial breakdown

Question 6

What are the advantages of microbial digestion in the hindgut?

Answer 6

• Not all food constituents are exposed to bacterial breakdown • Dietary protein, fats and non-structural carbohydrates can be digested and utilised by the animal in a similar way to the carnivores and omnivores • The amount of easily digestible substrates such as starch reaching the hindgut is much reduced and it is mainly the indigestible fibre which is acted on by the bacteria

Question 7

What are the disadvantages of microbial digestion in the hindgut?

Answer 7

• Only one opportunity to chew the food, therefore animals must chew thoroughly as it ingestsfeed • Digesta may not be held in the GI tract for sufficient time to allow optimal/complete bacterial action • Not all products of bacterial action will be absorbed (e.g. decreased amounts of bacterial amino acids absorbed)

Question 8

What are the two major benefits of colonic microbiota in carnivores?

Answer 8

1. may be to promote proliferation of intestinal epithelial cells 2. to help prevent the colonisation and proliferation of harmful bacterial species within the intestine

Question 9

How many bacteria per gram content are found in the rumen?

Answer 9

10^10 - 10^11 - mostly attached to fibres of food material

Question 10

How many protozoa per gram are found in the rumen?

Answer 10

10^5 - 10^6 - infiltrate cellulose and break it down from the inside

Question 11

What is bacterial symbiosis?

Answer 11

Some bacteria produce substrates necessary for other processes to be able to occur and vice versa - all the bacteria are working together

Question 12

What is the pH of a rumen?

Answer 12

pH = ~6.5

Question 13

how early is normal rumen flora established?

Answer 13

As early as 6 weeks in age

Question 14

What are the 4 main homeostatic balances that need to remain in check in the rumen for optimal efficiency?

Answer 14

1. pH 2. Low oxygen 3. Temperature - constant 4. Osmotic pressure - similar to blood

Question 15

what are the 2 most important bacterial species in ruminants and hindgut fermentors?

Answer 15

Ruminococcus spp. are the most important type, along with Fibrobacter spp.

Question 16

Are the numbers and different species more constant in a hindgut or ruminant?

Answer 16

The relative numbers of the different species are generally much less constant in the hindgut of the horse compared with the rumen of the cow.

Question 17

what bacteria ferment starch to lactic acid?

Answer 17

Streptococcus spp. and Lactobacillus spp.

Question 18

what is dysbiosis associated with?

Answer 18

Canine IBD

Question 19

What causes this?

Answer 19

Endotoxaemia - Systemic inflammatory response syndrome (SIRS)

Question 20

What is laminitis?

Answer 20

Sequela to grain overload and endotoxaemia - inflammatory response occurring within hoof capsules

Question 21

what is it called with you transfer microbe-rich digestive contents from one individual to another?

Answer 21

Transfaunation - repopulate gut with healthy microbiota

Question 22

what are seizures and clostridium indicative of in guinea pigs?

Answer 22

Enteritis

Question 23

What are these? What do they contain?

Answer 23

Caecotrophs: - contain microbes, Amino acids, VFAs, vitamins -mucous coated

Question 24

Who’s intestinal tract is this?

Answer 24

Kangarroooooo

Question 25

What causes carbohydrate overload in horses?

Answer 25

Too much starch in diet - escapes into the colon and the mammalian digestive enzymes are overwhelmed and most of the starch is now available for rapid fermentation in hindgut - streptococci and lactobacilli can increase dramatically and produce lactic acid.

Can lead to toxic shoc ksyndrome (endotoxaemia) which causes circulatory disturbances, organ failure and laminitis.

Question 26

What causes enteritis in guinea pigs?

Answer 26

Changes in diet, stress, illness or anesthesia which may alter gut motility and/or gut microbiota resulting in diarrhea, anorexia = clostredial enteritis secondary to antibiotic therapy.

Question 27

Which two animals do you need to be cautious when perscribing antibiotics?

Answer 27

Guinea pigs and Horses = never give oral penicillin