INTRODUCTION
Cattle and horses predominantly consume plant matter. They possess voluminous gastrointestinal tracts, often featuring complex structures like multiple-chambered stomachs, as seen in ruminants.
Digestion in herbivores primarily relies on symbiotic microbial fermentation processes to break down fibrous plant material. Carnivores exhibit comparatively simpler and smaller digestive systems optimized for rapid enzymatic breakdown of proteins and fats derived from animal sources. Species such as pigs and certain avian varieties display dietary versatility, consuming both plant and animal matter. Their digestive physiology encompasses a combination of enzymatic processes akin to carnivores and microbial fermentation similar to herbivores, facilitating the digestion of a diverse range of foodstuffs. Animals exhibit varied digestive adaptations aligned with their dietary preferences, ranging from specialized herbivores to carnivores and adaptable omnivores. Although animals consume food in its natural state, the conversion of nutrients from a non-absorbable to an assimilable form is imperative for proper utilization by the organism. This transformative process, known as digestion, is orchestrated by the gastrointestinal tract (GIT). Key facets of digestion include• Movement of Food: Food traverses the alimentary tract through peristaltic contractions, ensuring its sequential passage from the oral cavity to the stomach and onward through the intestines.
• Secretion of digestive juices: Specialized glands within the GIT secrete digestive juices replete with enzymes and other requisite compounds essential for the enzymatic breakdown of food constituents.
• Enzymatic/ microbial digestion: Upon arrival in the stomach and intestines, food undergoes enzymatic degradation facilitated by the enzymes present in digestive secretions. In certain instances, microbial communities also contribute to the breakdown of complex substrates.
• Absorption of nutrients: The intestinal mucosa, furnished with villi and microvilli, orchestrates the absorption of digested nutrients into the circulatory and lymphatic systems for subsequent distribution to cells and tissues throughout the organism.
• Control of digestive function: Regulatory mechanisms, encompassing neural reflexes and hormonal signaling pathways, orchestrate the precise coordination and modulation of digestive processes to optimize nutrient assimilation and waste elimination.
15.2