title: Importance of amino-acid and electrolyte balance in experimental diets used to determine the apparent metabolisable energy (AME) value of wheat.
abstract: 1. An experiment was done with male, Ross broiler chicks to study the effect of diet composition and electrolyte balance on the measurement of diet AME and performance parameters in diets containing high levels of wheat inclusion. 2. The control diet (G) was based on wheat (667 g/kg) with full-fat soya, soyabean meal, Extrupro and herring meal providing the protein supplements. The experimental treatments were based on 2 diets, one based on wheat (790 g/kg) with casein as the protein supplement and the other containing 667 g/kg wheat plus casein, cellulose and starch. Each of these was formulated to contain one of three concentrations of sodium and potassium bicarbonate giving final values for dietary electrolyte balance of approximately 90, 180 and 280 meq/kg diet. 3. DM intake was numerically lower with the lower level of wheat inclusion and LWG (P < 0.05) and gain:food (P < 0.001) were reduced. ME:GE was similar for the two levels of wheat/casein but higher (P < 0.001) than for the control diet. 4. The two higher electrolyte balances improved DM intake (P < 0.01), LWG and gain:food (P < 0.01) compared with the diets containing no added bicarbonate. ME:GE was unaffected by electrolyte inclusion. 5. Viscosity of ileal digesta supernatant fell (P < 0.01) with increasing bicarbonate inclusion but the value for the highest electrolyte level was still higher than for the control diet. 6. It is concluded that addition of both arginine and electrolyte is needed with a wheat/casein diet to improve performance to levels seen with a more commercial diet but that the determination of diet AME, with the type of fat addition used in this study, is unaffected by electrolyte balance. The interaction between electrolyte balance and in vivo viscosity requires further study.
authors.affiliation: Queen's University of Belfast.
authors.forename: K J
authors.initials: KJ
authors.lastname: McCracken
authors.forename: R A
authors.initials: RA
authors.lastname: Stewart
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000821:Animal Feed; D000818:Animals; D001835:Body Weight; D002645:Chickens / Q000378:metabolism* / Q000502:physiology; D004044:Dietary Proteins; D004573:Electrolytes / Q000378:metabolism*; D004734:Energy Metabolism / Q000502:physiology*; D008297:Male; D009753:Nutritive Value; D011897:Random Allocation; D014908:Triticum / Q000378:metabolism*; D014882:Water-Electrolyte Balance
chemical_list: D000596:Amino Acids; D004044:Dietary Proteins; D004573:Electrolytes