Definition of Nutrition
Ene-obong (2020) defined food as any substance-liquid or solid, which when consumed is capable of performing one or more of the following functions:
• Provide the body with energy to work
• Provide the materials that are used for growth, repair, maintenance, reproduction etc.
• Protect the body against disease, and regulate body processes. Food is therefore the first necessity of life and the most important factor in relation to the building and maintenance of life.
The study of the use of food in the body and the interpretation of the relationship between food and the functioning of the living organism is what we refer to as nutrition. In other words, nutrition is defined as the science of feeding and the scientific investigations into the food supplied or fed. The materials in food that perform the functions of energy provision, growth, repairs and regulation of body functions are known as nutrients.
Food Stuffs
Food stuffs vary in composition and nutrient contents. Succulent foods are rich in water, while grains are regarded as dry food. Food may also be classified based on their nutrient contents e.g. carbohydrates, proteins, fats, minerals and vitamins. Whatever the methods of classification, food stuffs must generally provide all the nutrient requirements and it is essential to study how best these allowances can be met by a combination of suitable foodstuffs.
The feeding stuffs of domestic animals may be taken to consist of some of the following groups of feeds:
• Energy feeds
• Plant and animal by-products
• Food additives, and
• Forage.
This classification is based on the nutrient composition of the feed, the use of the feed and the bulkiness.
(i) Energy Feeds: The feeds that belong to this group are the:
• Roots and tubers such as cassava, yam and potatoes
• Cereals such as maize, sorghum, millet and rice
• Other seeds of energy origin that do not belong to the above groups e.g. cowpea, Soya-beans, groundnut etc.
Roots and tubers are high in energy content but low in protein content. Yams are usually consumed by human beings and therefore generally not grown for livestock feeding.
Cassava and potatoes are produced both for livestock and human consumption. The dry matter content of roots and tubers is very small. They supply very little vitamins and are low in calcium but have a fair amount of phosphorus. They are highly digestible, and can be processed and made into meals.
Cereals are very important in the feeding of livestock especially nonruminants. Human beings also compete with livestock for cereals. Cereals are high energy feeds with appreciable amount of protein. Their fiber content is low and most of them lack essential amino-acids, minerals and vitamins. Legumes in addition to being used extensively as forages provide seeds which have high protein content. Legume seeds are generally deficient in methinine which is one of the essential amino-acid. The meals got after extracting the oil are very good feeding stuffs for livestock.
(ii) Plant and Animal By-Products: Plant and animal by-products are normally referred to as concentrates. They are feeds prepared from cereals and other materials used in feeding farm animals. Concentrates consist of the followings: carbohydrate products such as processed wheat, maize, millet, sorghum, plant proteins such as groundnut cake, cotton seed cake, Soya-beans cake etc. roots and tubers processed into pellets etc. animal protein such as fish meal, bone meal, blood meal and miscellaneous by-products such as wheat bran, rice bran, maize bran, brewer’s yeast and grains. Plant and animal by-products are used to feed livestock to supply all the necessary requirements of the body for the optimum growth and production of meat, milk, egg, wool, hides and skins etc.
(iii) Forages Forages: These are characterized by the relative large amount of crude fiber. That their dry matter contains forages constitute complete food for ruminant farm animal as long as they are not grown on soils that are deficient in essential nutrients. Forages consist of the following: plant legumes such as centrosema, pueraria, stylosanthes, calapogonium etc., grasses such as guinea grass, elephant grass etc., roughages like hay, straws, dry grasses and haulms from maize, sorghum, rice, millet, groundnut etc.
(iv) Food Additives: Most feeding stuffs are deficient in the essential amino-acids, vitamins and mineral nutrients. It may not be possible to supplement all the require nutrients through the feeds. It becomes necessary therefore to look for other sources of making up for the deficiencies. This can be done through the addition of food supplements called food additives. Compounds of animal feeds normally add vitamins, minerals, aminoacids and growth stimulating compounds to the rations.
Examples of food additives include:
• Antibiotics
• Hormones
• Synthetic and natural vitamins
• Salts
• Proteins
• Amino acids like lysine
• Pre-mix • Anti-oxidants
• Grits • Anti-fungal
• Drugs etc