energy (AME) of the diet and gross energy (GE) of the diets and excreta were determined according to the method described by Khan et al.
Along with phytase, xylanase (Econase XT, AB Vista, Marlborough, UK) at 16,000 BXU/kg was incorporated to all experimental diets, and a contribution of 75 kcal/kg of metabolizable
energy from this enzyme was considered.
energy was calculated following NRC (1994) procedures of estimation.
Total digestible nutrients (TDN = DCP + 2.25DFA + DNDFP + DNFC - 7), digestible energy [DE = (DCP/100)5.6 + (DFA/100)9.4 + (DNFC/100)4.2 + (DNDF/100)4.2 - 0.3] and metabolizable
energy (ME= DE0.82) were calculated according to the National Research Council (NRC, 2001), in which: DCP = digestible crude protein, DFA = digestible fatty acids, DNDF = digestible neutral detergent fiber, [DNDF.sub.P] = digestible neutral detergent fiber free of digestible proteins, and DNFC = digestible nonfiber carbohydrates.
Por ultimo, se estimo el balance de energia neta de lactancia (ENL), el cambio de peso y los balances de proteina metabolizable
(PM) y de proteina degradable en rumen (PDR) utilizando el software (NRC 2001).
Ironically, the volatile fatty acids that ultimately become the glucose required for the ruminant's metabolizable
energy are actually a byproduct of the life cycle of the rumen microbes as they consume cellulose and other carbohydrates.
Researchers working in INRA Units, educators, and others in France who specialize in the nutrition and feeding of ruminants provide 26 chapters that describe biological concepts and equations used to predict intake, including in grazing situations, and nutrient supply from dietary intake; animal requirements and responses to diets, in terms of net energy, metabolizable
protein and amino acids, water, minerals, and vitamins; their use in dealing with new issues in rationing and the evolution of systems to address multiple responses of animals to diet, rather than building the appropriate diet for a given productive performance; and the reference methods and prediction equations to assess tabulated feed values of forage, concentrate, and byproducts, including feed resources in warm areas.
The energy content evaluation of feedstuffs used for pig diets is generally based on their digestible (DE) or metabolizable
(ME) energy values.
"Providing accurate information about metabolizable
energy (ME) content--calories--of foods is important for reliable food labeling and has health ramifications," says Novotny.
We easily see why reputable dog food companies now provide super premium products for hard working dogs in the range of 1,900 Kcal of metabolizable
energy per pound.
The presence of readily metabolizable
carbon sources like glucose, cellobiose, xylobiose, or xylose represses the synthesis of xylanase enzymes for the utilization of certain carbon sources such as xylan or cellulose and the process is known as catabolite repression.