Hindgut Fermenters Flashcards
Which linkages in soluble carbs?
Alpha
Which linkages in insoluble carbs?
Beta
List the macronutrients
Carbohydrates, Proteins, Lipids
Unit of measuring macronutrients?
g/kg
What are micronutrients?
Vitamins and minerals
Unit of measuring micronutrients
mg/kg
How are proteins, lipids and alpha linked soluble carbs digested?
Enzymatic (secreted by animal)
How are insoluble beta linked carbs digested?
Microbial fermentation
Describe diet of herbivores
High in CHO, low protein, low E
Consume lots to satisfy nutrient and E requirements
Spend lots of time eating
What 2 things does hindgut fermenter GIT need to enable?
Enzymatic digestion of soluble compounds
Microbial fermentation of insoluble compounds
Is enzymatic a quick or slow process?
Quick (0.5 hrs in equids)
Where does enzymatic digestion take place?
Stomach and/or si
Is microbial fermentation a quick or slow process?
Slow (1-2 days in equines)
Where does microbial fermentation take place in ruminants and hindgut fermenters? (What are the fermentation chambers?)
Ruminant: foregut (rumen)
Hindgut fermenters: hindgut (caecum and colon)
Describe generally the GIT components of hindgut fermenters
Have unremarkable si and large caecums and/or colons
List 4 cæcal fermenters
Guinea pig
Hamster
Rabbit
Koala
List 4 colon fermenters
Orangutans
Equids
Rhinoceros
Elephants
Aside from herbivores, which other feeders utilise hindgut fermentation and provide 2 examples
Hint: also benefit from a diet higher in protein and soluble CHO but still have fairly well developed caecum, and/or colon
Omnivores
Rats have well developed caecum
Pigs have well developed caecums and colons
Do rabbit and Guinea pig teeth continually grow or erupt?
Grow
Do horse teeth continually grow or erupt, what do you call this?
Erupt, hypsodont teeth
Which teeth continually grow in rats?
Incisors
What is the morphology and purpose of the incisors in hindgut fermenting herbivores?
Sharp and overlapping for cutting leaves and twigs
What is the purpose of having flat molars creating an occlusal surface?
To grind fibrous ingests into smaller particles
In terms of dentition, why must fibrous feed be provided?
To wear down teeth
What are the caecum and/or colon called in hindgut fermenters?
Fermentation chambers
What is the role of saliva from salivary glands?
Lubricate food when swallowed and buffer acid in stomach
Which additional salivary gland (to parotid, mandibular and sublingual) do rabbits have?
Zygomatic
Describe saliva prod in rabbits
Continually from mandibular gland and in response to food intake by others
Describe saliva prod in horses
In response to chewing only
What three components are always present in saliva?
Water and mucus for lubrication and bicarbonate to buffer acidic contents of stomach
What else is present in rabbit and and rat saliva but not in horses?
Alpha amylase (starch digestion) but action is low
Describe the stomach of hindgut fermenters
Small and simple
Describe their feeding strategy
Trickle
How fast does ingests pass thru the stomach?
Fairly rapidly (usually 15mins to 2hrs but slightly slower in rabbits)
Through what structure does food enter the stomach?
Cardiac sphincter (prevents regurgitation in horse, rat, gp, rats)
Describe cardiac region of stomach
Non glandular, pH 6-7, no secretions = no protective mucus lining
Describe funding and pyloric regions of stomach
Main secretory part
Parietal cells secrete HCl
Chief cells secrete pepsin
Mucus secreted to protect against acid
pH 1-2
Describe pyloric region of stomach
Gastric secretion stimulates HCl production
Which species needs continuous HCl secretion in stomach to help prevent ulcers?
Equines
Where does ingesta exit stomach
Pyloric sphincter
Which type of bonds are targeted by enzymatic secretions in the stomach and si?
Alpha bonds
How long does it take for ingesta to pass through si of hindgut fermenters?
1-3hrs
Describe how ingesta passed from si to colon in equids
Ileum to caecum via iléocaecal valve then leave caecum via caecoventral colonic valve
Describe how ingesta passed from si to colon in rabbits
Three way connection btwn ileum, caecum and colon, called the iléocaecocolic junction
What is the function of the ileocaecocolic junction structure in rabbits?
Facilitâtes selective retention of fluid and small particles and expulsion of fibrous material
Remember rabbits are cæcal fermenters whilst horses ferment in caecum and colon
Which food materials remain upon entry to the large fermentation chambers?
Insoluble fibrous materials: hemicellulose, cellulose, lignin (completely indigestible)
Why do fermentation chambers need to be able to store ingesta?
The process of microbial fermentation in the caecum and colon takes time
Describe the function of the caecum and colon in hindgut fermenters
Provide space for mixing ingesta with microbial populations and a large surface area for abs of nutrients, fermentation prods and water