Energy Metabolism and Protein Utilization in Chicken- A Review

Abstract

Evaluation of energy in the diet is very important in animal nutrition because food intake is strongly influenced by the energy content of the diet. This means that the intake of other nutrients, such as amino acids, is affected by their ratio to energy content. Poultry can control their energy intake over a range of energy: protein ratios. Energy: protein ratio also affects the growth and body composition. Therefore we need to know what extent the relationship between energy and dietary protein influences the bird's performance. To predict the energy value of the diet or its chemical constituents, researchers have been working on modelling using the equations of the major biochemical pathways in terms of ATP generation and utilization. The activity of feeding and the metabolism caused by digestion and assimilation of food increase the animal's heat production and it can be measured by calorimetry technique. Theoretically, surplus amino acids which are not needed for protein synthesis stimulate an additional increase in metabolic rate and lead to increased energetic costs of catabolism and excretion. However, it has sometimes been shown that there was no measurable diet-induced thermoregulatory effect when an imbalanced amino acid mixture was fed. All these aspects are discussed in this review.

Determination of metabolisable and net energy contents of corn fed to Arbor Acres broilers and Beijing You chickens

“…In addition, the result of the present study showed that HI decreased in the test diet group compared with the basal diet group of BJY1 and BJY2 chickens, which could be explained by the lower nitrogen excretion. Because the surplus amino acids would stimulate an additional increase in metabolic rate and lead to increased energetic costs of catabolism and excretion (Kim, 2014).…”

“…It may be that the fat content in gained body weight was higher in slow-growing chickens than in fast-growing chickens (Zelenka et al, 2011), fat tissue contributes little to HP compared with that of muscle, and animals with high-fat rates have lower energy requirements than animals with low-fat rates (Close, 1990). Macleod et al (1988) metabolic rate and lead to increased energetic costs of catabolism and excretion (Kim, 2014).…”

Energy Values of Corn and Rice Bran and Energy Levels for Ducks – Basis in Establishing Energy Requirement for Improved Philippine Mallard Duck

“…Evaluating the energy in the diet is imperative in animal nutrition because feed intake is strongly influenced by the energy content of the diet. This implies that the intake of other nutrients such as amino acids is affected by their ratio to the energy content of the feed consumed by the animal (Kim, 2014). For this reason, understanding energy metabolism in poultry is important to determine the exact energy utilization capacity and requirement of the poultry species specifically when comparing a native breed to their commercial breed counterparts.…”

“…Different energy evaluating systems have been used to formulate poultry diets including digestible energy, total digestible nutrients, true metabolizable energy, apparent metabolizable energy (AME), and effective energy. The ME system or AME values of raw materials are most commonly and widely used to formulate poultry diets (Barzegar et al, 2020;Kim, 2014). This is because of the exceptional digestive anatomy of poultry species where the feces and uric acid excreted by the birds are mixed in the cloaca, a single opening at the end of the digestive tract (Dunaway, 2019).…”