Back to: Animal Husbandry SS 2
The enzymes are the following: (a) Lipase which converts fats and oil to fatty acids and glycerol. (b) Erepsin converts polypeptides to amino acids. (c) Maltase converts maltose to glucose. (d) Sucrase converts sucrose to glucose and fructose. (e) Lactase converts lactose to glucose and galactose.
The end products in digestion include the conversion of: (i) protein to amino acids (ii) starch to glucose (iii) fats and oil to fatty acids and glycerol.
These end products (amino acids, glucose and fatty acid and glycerol) are absorbed in the small intestine by a structure called the villi. The undigested food materials are passed to the large intestine from where they are ejected through the anus as faeces or dung.
The digestion of food in rabbit (a non ruminant) is just like the pig except that rabbit can feed properly on grasses which are digested in the large caecum which contains micro organisms like bacteria and protozoa.
Digestion in Domestic Fowls
The domestic fowl is a monogastric animal and has a simple stomach. The digestion in fowls can be explained properly with the help of the diagram.
The fowl has no teeth but the food is picked up by the beak. This food then passes on to the crop through the oesophagus. This food is stored temporarily in the crop where it is moistened and fermented by some bacteria. The food now passes on to the proventriculus where digestive enzymes are secreted on the food.
The proventriculus is often regarded as the glandular stomach because it secretes digestive enzymes on the food like pepsin and amylase.m From the proventriculus, the food moves to the gizzard where grinding takes place. With the aid of small stones or grits, the food is ground by the gizzard. From the gizzard, the food now moves to the duodenum and small intestine where further digestion and absorption take place while the undigested food materials are removed from the tract as faeces.
Importance of Digestive System
(i) It aids the ingestion of feed.
(ii) It promotes the digestion of feed.
(iii) It ensures the absorption of digested feed.
(iv) It helps in the ejection of undigested feed.
(v) It aids the secretion of productive hormones and digestive enzymes.
CIRCULATORY SYSTEM
Circulatory system involves all the organs and tissues which are concerned with the movement of materials from one part of the body to another where they are either used or removed. These organs and tissues include the heart, the blood and the blood vessels.
Composition of Blood
Blood is a fluid tissue. It is made up of two parts: the fluid plasma and the blood cells or corpuscles.
Plasma: Plasma is the liquid portion of the blood. It is made up of water, blood protein like globulin, fibrinogen, prothrombin, dissolved mineral salts and other organic substances like hormones, enzymes, digested food and waste products within the body.
(2) The Blood Cells (Corpuscles): There are three blood cells or corpuscles. These are:
(i) Red Blood Cells (Erythrocytes): These are biconcave and circular in shape, non nucleated when mature. They are manufactured by the bone marrow and any excess is stored in the spleen. Erythrocytes contain an iron pigment called haemoglobin which helps to transport oxygen.
(ii) White Blood Cells (Leucocytes): They are irregular in shape, larger but fewer than red
blood cells. They have nuclei and are produced in the lymphatic tissues. The phagocytic leucocytes attack and destroy foreign organisms in the body. In other words, white blood cells defend the body against foreign germs.
(iii) The Blood Platelets (Thrombocytes): They are irregular or star-shaped, tiny and non nucleated. They are produced in the red bone marrow. The white blood cells are responsible for blood clotting.
Functions of the Blood
(1) It maintains body temperature by distributing heat during circulation.
(2) The red blood cell carries oxygen with the help of haemoglobin to different parts of the body. to quobem et son on
(3) It transports hormones from ductless glands to their areas of activities.
(4) It transports waste products like carbon dioxide, mineral salts, urea and water to where they are removed.
(5) Leucocytes helps to defend the body against germs.
(6) It helps in blood clotting with the aid of platelets.
(7) It also helps to transport digested food to the cells.
(8) It also helps to maintain the water level of the body.
The Heart
The heart is the most powerful organ in the circulatory system. It helps to pump blood round the body. Each pumping action of the heart is known as heartbeat.
The heart is made up of muscles called the cardiac muscles which contract and relax continuously, making the heart to beat ceaselessly. It is covered and protected by a thick membrane called pericardium which keeps the heart in good position in the thoracic cavity.
The heart consists of four chambers: the upper auricles (right auricle and left auricle) and the lower ventricles (right ventricle and left ventricle). A central wall called the septum divides the heart into right and left halves.
Between the left auricle and the left ventricle is an aperture guarded by a biscupid or mitral valve and another valve. The triscupid valve is found between the right auricle and the right ventricles. These valves only permit one direct flow of blood.
Heartbeat occurs in two stages: (i) Diastole (ii) Systole.
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