Epithelium contains Absorptive and Goblet cells. Both Absorptive and Goblet cells are located within long tubular Intestinal Glands extending the full thickness of the mucosa. No circular folds, no villi, but microvilli are present on the absorptive cells. NO digestive enzymes. Microbes ferment digesta/fibre
Fermentation in the Equine Hindgut
The small intestine absorbs a significant amount of the simple sugars, starch, proteins and fats in the diet Fibre is indigestible by the enzymes in the small intestine Some starch and sugars, in addition to fibre, are swept to the cecum for fermentation Proper function of the hindgut requires: 1. Adequate substrate supply 2. Proper pH 3. Osmolarity (hyper and hypotonic solutions – swell/explode or shrink) 4. Anaerobiosis (no oxygen) 5. Adequate retention of substrate – keeps fibre in long enough to ferment 6. Prompt removal of waste products (bacterial) 7. Healthy population of microflora
Disruption of any of these disturbs digestion
Among the fermenters, two distinct strategies have evolved. The chief difference between the two groups is in positioning of their fermentation vat relative to the stomach and small intestine: 1. Cranial fermenters or ruminants have a large, multi-compartmented section of the digestive tract between the esophagus and true stomach. These forestomachs house a very complex ecosystem that supports fermentation. Examples of ruminants are cattle, sheep and deer. 2. Caudal fermenters, also known as cecal digesters, are similar to dogs and humans through the stomach and small intestine, but their large intestine, where fermentation occurs, is complex and exceptionally large. Examples of cecal digestors include horses and rabbits. The process and outcome of fermentation is essentially identical in the rumen of a cow or the cecum of a horse. However, the positioning of the fermentation vat in relation to the small intestine has very important implications for animal's physiology and nutrition. These similarities and differences can be summarized as follows:
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