Feed intake adjustments by hens to feeding regimens in which dietary methionine is varied

At 20 wk of age, 315 ISA Brown pullets were individually caged and randomly assigned to one of seven feeding regimens for the next 20 wk. In Regimen 1 Diet A was fed, in Regimen 2 Diet B was fed, Regimens 3 and 4 alternated Diets A and B weekly (the week Diet A was fed in Regimen 3, Diet B was fed in Regimen 4), Regimens 5 and 6 alternated Diets A and B monthly (reversing as with 3 and 4), and in Regimen 7 pullets were given a choice of Diets A and B. Diet A was methionine-deficient (.23%) and Diet B was balanced for methionine (.33%). Feed and nutrient consumption, egg production, egg weight, and egg mass were lower in Regimen 1 than 2. Pullets in Regimen 1 lost body weight and those in Regimen 2 gained weight. Overall feed consumption for Regimens 3 through 7 was similar to that for Regimen 2. For Regimens 3 through 6, however, consumption increased when the balanced diet was fed and decreased when the deficient diet was fed. Concomitant with these oscillations in feed consumption were changes in egg mass, so that means for these traits were intermediate and different from those for Regimens 1 and 2. For Regimen 7, in which Diets A and B were continuously available, no preference of diet was observed during the first 4 wk.(ABSTRACT TRUNCATED AT 250 WORDS)