DIETARY ARGININE AND LYSINE RATIOS IN LARGE WHITE TOMS - 2 - LACK OF INTERACTION BETWEEN ARGININE-LYSINE RATIOS AND ELECTROLYTE BALANCE

The effect of dietary Arg:Lys ratios and dietary electrolyte balance ( DEB) on growth and carcass parameters of Large White toms was evaluate d in one experiment from 8 to 20 wk of age. Growth, feed conversion, a nd carcass composition were measured. All toms received a common basal diet from 0 to 8 wk of age. At 8 wk of age, 600 tom were randomly pla ced into 40 pens (15 toms per pen). The corn-soybean meal-based experi mental diets were fed from 8 to 12, 12 to 16, and 16 to 20 wk of age a nd evaluated two Arg:Lys ratios (0.98 vs 1.22) and two DEB levels (148 vs 202 mEq/kg of diet) in a complete factorial arrangement. All exper imental diets were pelleted. Composite samples of protein-contributing ingredients and complete experimental diets were analyzed for all ami no acids, CP, DM, Cl, Na, and K. High and low average house temperatur e for the 8 to 20 wk period were 19 and 15 C, respectively. No interac tions occurred between Arg:Lys ratios and DEB for any parameter measur ed except litter moisture. Increasing the Arg:Lys ratio improved 20-wk BW (P less than or equal to 0.027) and 8 to 20 wk gain (P less than o r equal to 0.023). Feed:gain from 0 to 20 wk Of age was decreased by i ncreasing the Arg:Lys ratio (3.01 vs 2.94; P less than or equal to 0.0 26) and by increasing the DEB (3.01 vs 2.95; P less than or equal to 0 .045). Dietary treatments did not affect mortality. Increasing DEB dec reased cold carcass yield (P less than or equal to 0.020). Total breas t meat yield was increased (P less than or equal to 0.076) by 1% in to ms fed the diets containing the 1.22 Arg:Lys ratio vs toms fed diets c ontaining the 0.98 Arg: Lys ratio. Toms responded favorably to increas ing the Arg:Lys ratio for growth, feed conversion, and breast meat yie ld independent of DEB level.