Nutrition in Animals - Types, Process of Nutrition in Animals
Nutrition in animals depends upon the feeding habits of the animals. Animals derive their nutrition either by eating plants directly (herbivores), or indirectly by eating animals which have consumed plants (carnivores). Some animals feed on both plants and animals; these animals are termed as omnivores. All organisms require food for their survival and growth.
NUTRITION IN ANIMALS
WHAT IS NUTRITION ?
MODE OF INTAKE OF FOOD
FOOD HABITS OF ANIMALS
UTILISATION IN THE BODY
TYPE OF NUTRITION IN ANIMALS
- Fluid feeding: obtaining nutrients by consuming other organisms’ fluids. Honey bees, mosquitos exhibit this mode of food intake.
- Filter Feeding: obtaining nutrients from particles suspended in water. Commonly used by fish.
- Ram feeding and suction feeding: ingesting prey via the surrounding fluids. This mode of ingestion is usually exhibited by aquatic predators such as bony fish.
- Bulk feeding: obtaining nutrients by eating the whole of an organism. Example: Python.
- Deposit feeding: obtaining nutrients from particles suspended in the soil. Earthworms use this mode of ingestion.
PROCESS OF NUTRITION IN ANIMALS
Amoeba
- Amoeba ingests its food with the help of pseudopodia.
- The food is engulfed by forming a vacuole and is digested with the help of digestive enzymes.
- The digested food is absorbed directly into the cytoplasm by the process of diffusion.
- Energy is obtained from the absorbed food that helps in its growth.
- The undigested food is egested out of the body of amoeba by rupturing the cell wall.
Ingestion
The food is ingested with the help of the tongue and chewed. Ruminants have sharp incisors and large molars to bite and chew grass. They also have powerful jaw muscles.
Digestion
After being chewed once, the food passes down the 2 to 3 feet long oesophagus. The oesophagus leads into the stomach. The stomach of ruminants has four chambers: rumen, reticulum, omasum, and abomasum.
Rumen: The rumen helps in storing the large quantities of food that has been quickly consumed. The food is partially digested here and is now called the cud. The cud is then brought back to the mouth, re-chewed, and re-swallowed in a process called cud-chewing. The rumen has billions of bacteria and protozoa, which break down the carbohydrate called cellulose found in hay and grass.
Reticulum: The reticulum helps in moving the swallowed food back into the mouth for thorough chewing. The reticulum opens into the omasum.
Omasum: The omasum absorbs excess water.
Abomasum: The walls of the abomasum secrete digestive juices.
Absorption
Absorption begins in the four-chambered stomach, but the main absorptive organs are the intestines. The food from the abomasum passes into the small intestine, where it mixes with secretions from the pancreas and liver. Most of the digestion of- carbohydrates, proteins, and fats takes place here. Several villi are present here, which help in increasing the surface area for absorption.
The small intestine leads into the large intestine. The main function of the large intestine is to absorb water and eliminate the undigested food as faeces.
- Ingestion is the process the food is taken inside through mouth and broken down by teeth and initial digestion takes place in the mouth by saliva.
- Digestion is the process in which food is digested by using few enzymes and is used by the cells for producing energy.
- Absorption is the process in which cells use the energy from the digested food and helps in building tissues in our body.
- Assimilation is the process in which digested food moves into the cells of the body.
- Egestion is the process in which undigested food is removed out from the body through excretion.
TWO MOST ASKED QUESTIONS IN EXAMS
What are the two important modes of nutrition?
The two important modes of nutrition include:
- Autotrophic nutrition: In this type of nutrition, the plants and other photosynthetic organisms prepare their own food with the help of sunlight, water and carbon dioxide.
- Heterotrophic nutrition: The animals cannot prepare their own food. Therefore, they have to rely on other animals for nutrition. This is known as heterotrophic nutrition.
Why is nutrition important for animals?
Nutrition helps in proper growth and maintenance of the cells. It provides energy to carry out different life processes.
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