tailieunhanh - Small-scale chicken production - Part 3

5 Nutrition This chapter describes nutritional requirements, feeding methods and feed composition. Also water is treated as a nutrient, since it is necessary for life. The nutritional requirements of chickens are shown in figure 24 and table Figure 24: Feeds and nutrients (Poultry Network) | 5 Nutrition This chapter describes nutritional requirements feeding methods and feed composition. Also water is treated as a nutrient since it is necessary for life. The nutritional requirements of chickens are shown in figure 24 and table 4. Figure 24 Feeds and nutrients Poultry Network Nutrition 33 Table 4 Essential nutrients in a poultry diet Letter in Figure 24 Nutrient category Possible nutrient source Top water rainwater tap water spring water a energy starch from grains or tubers fat from seeds b protein soy beans fish insects d vitamins fruit green vegetables animal products c minerals bone-ash shells limestone Water The body of a bird is made up of 70 water and eggs are approximately 65 water. Poultry must have a continuous supply of clean fresh water so that nutrients can be absorbed and toxic materials removed from the body. This is especially vital for young chicks. A lack of water will reduce feed intake seriously retarding growth and impairing egg production. This is particularly true in hot climates where deprivation can rapidly lead to death. Water is also essential for birds to control their body temperatures in hot weather. Birds need a lot more water at high temperatures than at low temperatures and lack of water quickly leads to death by overheating. It is undesirable to restrict any bird s water intake particularly in the tropics. Even a 10 restriction in the amount of water available can reduce the growth rate and feed conversion efficiency amount of feed needed per kg growth of broilers. With layers the effect is even more devastating. Short periods of deprivation can result in moulting and the cessation of egg production. Energy requirements The energy intake means the calories that are taken in by the chicken with its feed see figure 25 for a schematic design. The amount of energy contained in feedstuffs is normally expressed in units of metabolisable energy ME per unit weight. The metabolisable energy refers 34 Small-scale chicken