Four experiments were conducted to determine the arginine and lysine requirements of male chickens for 2- to 3-wk intervals from the time of hatching until 8 wk of age. Weight gain, breast muscle growth, and feed efficiency were used as response for each interval. Dietary requirements for lysine and arginine were estimated by broken-line regression analysis of responses to six or seven dietary levels of each amino acid. Dietary crude protein levels were 22, 21, 20, and 18% in four consecutive experiments from 0 to 2, 2 to 4, 3 to 6, and 5 to 8 wk of age. An occasional estimate of requirement was not determined (ND) because the response did not conform to the regression model. The values for lysine and arginine requirements determined from breast muscle gain (weight gain of pectoralis major plus pectoralis minor) were not significantly higher than those from body weight gain. However, they tended to be higher than for feed efficiency for 0-to-2 and 2-to-4-wk-old broilers. Lysine and arginine requirements, as percentages of total amino acid in the diet, for maximum breast muscle growth were, respectively, 1.32+/-0.01% and 1.27+/-0.00% to 2 wk of age, 1.21+/-0.06% and ND for 2 to 4 wk of age, 0.99+/-0.02% and 0.97+/-0.02% for 3 to 6 wk of age, and 0.81+/-0.01% and 0.83+/-0.02% for 5 to 8 wk of age. Calculated digestible lysine and arginine requirements were, respectively, 1.24 and 1.19% to 2 wk of age, 1.11% and ND for 2 to 4 wk of age, 0.92% and 0.91% for 3 to 6 wk of age, and 0.75 and 0.78% for 5 to 8 wk of age. The requirements for lysine and arginine were similar except for the earliest age group for which the lysine requirement appeared to be slightly higher than that of arginine.

BackgroundThis study was to determine if feeding laying hens with defatted diatom microalgal biomass (DFA) from biofuel production affected their egg production and health status.MethodsFive replicates of 5 individually caged ISA Babcock White leghorn hens were fed 4 diets, including a corn-soybean meal control diet, a diet containing 7.5% DFA substituting for soybean meal, and diets containing 7.5% or 15% DFA substituting for corn and soybean meal. Body weights, feed intake, feed conversion ratio (FCR), rate of egg production, egg size, egg mass, and several characteristics of eggs were determined at 4 and 8 wk. Venous blood was sampled at 4 and 8 wk for measurement of 5 biomarkers of health.ResultsThe 15% DFA diet decreased (P < 0.05) feed intake, egg production, and plasma uric acid concentrations as compared with the control diet, but increased (P < 0.05) egg albumen weight and height compared with the 7.5% DFA diets. The two levels of DFA produced dose-dependent (P < 0.05) changes in three color measures of egg yolk, without affecting four hen plasma biochemical indicators of health.ConclusionsFeeding laying hens with 7.5% DFA in the corn-soybean meal diet for 8 wk had no adverse effect on their health, egg production, or egg quality, but 15% inclusion reduced feed intake, egg production, and efficiency of feed utilization.