Exploiting calcium-specific appetite in poultry nutrition

Calcium is the most prevalent mineral in the body and is important for many physiological processes. However, the amount of calcium in modern diets has both economic and nutritional consequences for producers. Dietary calcium has been shown to reduce the efficacy of both endogenous and exogenous phytases resulting in decreased phytate-phosphorus availability, increased phosphorus excretion as well as facilitating the formation of mineral-phytate complexes. Reducing the concentration of dietary calcium has been reported to improve phytase efficacy and phytate-phosphorus availability, however, this is often at the expense of optimal skeletal integrity. Choice feeding employs the principle that poultry have the ability to select a nutritionally balanced diet from multiple sources and previous studies have shown that poultry have a calcium specific appetite. However, the evaluation of choice feeding systems for broilers has predominantly focussed on the effects of providing separate sources of protein and energy concentrates. Though literature is available for laying hens, scant information is available pertaining to choice feeding of a separate calcium source for broilers. This paper reviews the available information on choice feeding systems in poultry with focus on the application of this in broiler production systems.