Main Difference – Monogastric vs Ruminant Digestive System
The digestive system of animals is involved in the mechanical and chemical digestion of food, absorption of nutrients, and elimination of indigestible materials from the body. The main difference between monogastric and ruminant digestive system is that the digestion in the monogastric digestive system mainly occurs in the stomach whereas the digestion in the ruminant digestive system is a foregut fermenter type digestion. The monogastric digestive system is composed of a single stomach while the ruminant digestive system is composed of four stomachs. Monogastric digestive systems mainly occur in omnivores and carnivores.
Key Areas Covered
1. What is a Monogastric Digestive System
– Definition, Components, Role
2. What is a Ruminant Digestive System
– Definition, Components, Role
3. What are the Similarities Between Monogastric and Ruminant Digestive System
– Outline of Common Features
4. What is the Difference Between Monogastric and Ruminant Digestive System
– Comparison of Key Differences
Key Terms: Carnivores, Foregut Fermentation, Herbivores, Human, Monogastric Digestive System, Ruminant Digestive System
What is a Monogastric Digestive System
The monogastric digestive system refers to the organ system which helps the digestion of both animal and plant materials. It is called as monogastric since this digestive system is composed of a single stomach. Human, horse, swine, fowl, dog, and rabbit-like animals have a monogastric digestive system. The system is composed of a mouth, esophagus, stomach, small and large intestine, and anus. The digestion begins with the entering of food to the mouth. Both chemical and mechanical digestion starts at the mouth. Saliva contains enzymes to digest carbohydrates. The esophagus is the passage that leads food to the stomach. Various enzymes are secreted into the lumen of the stomach to digest proteins in the food. The human digestive system is shown in figure 1.
Figure 1: Human Digestive System
Animals with a monogastric digestive system mainly take animal tissues as food. Their diet is easy to digest. Thus, a single stomach is enough for the purpose. Small intestine mainly absorbs the nutrients from the digested food. The large intestine absorbs water from the indigestible materials. The elimination of the indigestible materials occurs through the anus.
What is a Ruminant Digestive System
The ruminant digestive system refers to the organ system in which the digestion of plant materials occur. Cow, cattle, sheep, deer, and goat the examples of the animals having a ruminant digestive system. The top jaw of ruminant animals lacks teeth in the front, but instead, a hard pad of skin is present, which is called the dental pad. Other than the basic anatomy of an animal digestive system, the ruminant digestive system is composed of four stomachs. They are rumen, reticulum, omasum, and abomasum. The first three stomachs, the rumen, reticulum, and omasum, are involved in the breaking down of plant fibers. The population of microflora is involved in this process. It breaks down cellulose through fermentation, producing volatile fatty acids such as acetate, butyrate, and propionate. These fatty acids are utilized by the cow as a nutrient. Digestive enzymes are secreted in the fourth stomach called the abomasum. Therefore, fermentation occurs before the digestion of food in ruminant animals. Hence, this process is called the foregut fermentation. The four stomachs of the ruminant digestive system are shown in figure 2.
Figure 2: Four Stomachs of the Ruminant Digestive Systems
Furthermore, ruminant animals chew the partly digested food or cud by returning them from the first stomach. Small intestine and large intestine of cows are similar to the monogastric digestive system. However, ruminants comprise a large caecum for further digestion of the fibers.
Similarities Between Monogastric and Ruminant Digestive System
- Both monogastric and ruminant digestive systems are involved in the digestion of food, absorption of nutrients, and elimination of indigestible materials.
- Both digestive systems comprise teeth, mouth, esophagus, stomach, small and a large intestine.
Difference Between Monogastric and Ruminant Digestive System
Definition
Monogastric Digestive System: Monogastric digestive system refers to the organ system in which the digestion of both animal and plant materials occur.
Ruminant Digestive Systems: Ruminant digestive system refers to the organ system in which the digestion of plant materials occur.
Type of Animals
Monogastric Digestive System: The monogastric digestive system is found in omnivores, who eat both plant and animal materials and carnivores, who eat only animal material.
Ruminant Digestive System: The ruminant digestive system is found in herbivores.
Type of Diet
Monogastric Digestive System: Monogastric digestive system is adapted to digest both plant and animal materials.
Ruminant Digestive System: Ruminant digestive system is adapted to digest plant materials.
Length
Monogastric Digestive System: The monogastric digestive system is short.
Ruminant Digestive System: The rudiment digestive system is long.
Enzymes to Digest Proteins
Monogastric Digestive System: The monogastric digestive system secretes enzymes to digest proteins.
Ruminant Digestive System: The ruminant digestive system lacks enzymes to digest proteins.
Canines
Monogastric Digestive System: Monogastric digestive system comprises four, sharp canines.
Ruminant Digestive System: The ruminant digestive system comprises two, blunt canines.
Premolars and Molars
Monogastric Digestive System: Premolars and molars of the monogastric digestive system move in the vertical direction.
Ruminant Digestive System: Premolars and molars of the ruminant digestive system move in the lateral direction.
Saliva
Monogastric Digestive System: A human produces 1-1.5 liters of saliva per day.
Ruminant Digestive System: A cow produces 65 liters of saliva per day.
Digestive Enzymes in Saliva
Monogastric Digestive System: The saliva of the monogastric digestive system contains carbohydrate digestive enzymes.
Ruminant Digestive System: The saliva of the ruminant digestive system lacks digestive enzymes.
Regurgitation
Monogastric Digestive System: The monogastric digestive system has no regurgitation.
Ruminant Digestive System: The ruminant digestive system has regurgitation during digestion.
Rumen/Stomach
Monogastric Digestive System: The monogastric digestive system comprises a simple stomach.
Ruminant Digestive System: The ruminant digestive system comprises a complex rumen.
Number of Stomachs
Monogastric Digestive System: The monogastric digestive system contains a single stomach.
Ruminant Digestive System: The ruminant digestive system contains four stomachs.
Liver
Monogastric Digestive System: Human liver weighs about 1.5 kg.
Ruminant Digestive System: Cow’s liver weighs more than the human liver.
Length of the Small Intestine
Monogastric Digestive System: The small intestine of human is 6.1 m long.
Ruminant Digestive System: The small intestine of a cow is 46 m long.
Length of the Colon
Monogastric Digestive System: The colon of human is 5-6 m long.
Ruminant Digestive System: The colon of a cow is 11 m long.
Conclusion
Monogastric animals mainly eat animal tissues, which are easy to digest. However, ruminant animals mainly eat plant materials, which are difficult to digest. Therefore, ruminant animals use natural flora to digest plant materials in their stomach. For this purpose, they consist of a large stomach with four compartments. On the contrary, monogastric animals consist of a single stomach. The main difference between monogastric and ruminant digestive system is the type of food and the adaptation of each type of digestive systems.
Reference:
1. “Digestive Systems.” Digestive Systems | Boundless Biology, Available here.
Image Courtesy:
1. “303364” (Public Domain) via Pixabay
2. “Abomasum (PSF)” By Pearson Scott Foresman – Archives of Pearson Scott Foresman, donated to the Wikimedia FoundationThis file has been extracted from another file: PSF A-10005.png (Public Domain) via Commons Wikimedia
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