The degree to which poultry in general and young chicks in particular is deprived of energy determines how much they are able to resist or succumb to any disease infection. During out-breaks of diseases caused by viruses’ it is the amount of energy that a chick has which determines the degree to which it is able to resist attack by such viruses.
Energy is acquired by poultry as glucose (the last product of carbohydrate metabolism) is catabolysed. Therefore in order to acquire energy, there has to be glucose which must be broken down to release energy. This energy is a’sine-qua-non1 for virtually every activity of the bird, whether external or internal activity. Consequently, external activities like running about, eating, drinking, lying down or getting up, all require the presence of this offspring of glucose (i.e. energy) before they can happen. Similarly, internal activities like respiration, absorption and assimilation of digested feed, formation of antibodies, formation of blood cells, etc. also require expenditure of energy before they can take place. It is thus clear that every aspect of the very existence of poultry requires energy.
The importance of energy to life is such that even when the bird is denied food for long periods, the law of self defense takes over the struggle for survival. In attempting to prevent the deadly consequences of lack of energy, all the energy which has been stored up in the body begin to be released, as none is being supplied through feeding. Firstly, energy stored up in the muscles and in the liver as triglycerides are, released and broken down to glucose
which then yields the energy as earlier described. Next, free fats stored all over the body are converted to glucose to yield the energy. As this is taking place, the animal emaciates gradually. When the fats are exhausted the proteins which constitute the muscles are called to the rescue. Proteins are broken down step by step until they yield fats and later glucose At this time the animal is so emaciated that bones of the skeleton become very prominent.
It is important to point out that in poultry, it is only after the birds have taken all the energy it required for all external and internal activities, and there are left-overs that egg production can take place. In effect, eggs are produced with extra energy derived from extra ration fed after enough ration for its basic needs have been fed. Fortunately, poultry does not even require up to half of the recommended daily feed level, before it satisfies all its basic metabolic and other vital needs. It is only when this recommended level is ignored or not met, that no products are got from it.
When too much energy has been spent, the animal feels very weak. When it is weak it is no longer able to vigorously fight disease-causing micro-organisms which are always present. The result is that resistance falls, and the animal becomes sick.
As has been described above, every activity of the body, no matter how slight, requires expenditure of energy. One of such many activities during which energy is wasted is maintenance of balance. When a bird is standing up several activities are going on in the brain and in the skeletal muscles which enable that bird not to fall over. Even when it
is lying down in a particular way, it is assisted to remain lying in that position by these brain and muscular activities. When young chicks are transported from the hatchery to the farm where they are to be raised, they spend a lot of energy in maintaining balance inside the cartons used in transporting them. If the journey is long and the road is rough, the amount of energy lost is so much that chicks are so weak and almost sickly by the time they get to the farm. The smoother the road, the less the energy lost. Transportation by air conserves much more energy than road transportation.
It will be seen from what has been said so far that one of the things a farmer should know as his birds arrive is that he has just received a group of weakened chicks whose resistance to disease has been lowered by transportation and other stress factors like handling; and something urgent should therefore be done to help them regain strength and thus be able to ward off the persistent aggression by disease causing agents.