ABSTRACT Three experiments were conducted to estimate the optimal digestible threonine to lysine ratios (Thr:Lys) of meat-type quails during the pre-starter (1 to 7 days), starter (8 to 14 days) and grower I (15 to 21 days) phases. In each experiment, 600 birds were distributed according to a completely randomized experimental design into five treatments, consisting of five dietary Thr:Lys ratios (0.66, 0.71, 0.76, 0.81 and 0.86%), with eight replicates of 15 quails each. Performance parameters and intestinal morphology were evaluated. During the pre-starter phase, feed intake, threonine intake, weight gain, and ileal villus height linearly increased (p<0.01) as dietary digestible Thr:Lys increased. During the starter phase, increasing digestible Thr:Lys ratios had a linear effect (p<0.01) on threonine intake and livability, and linear and quadratic effects (p<0.01) on feed intake. During the grower I phase, increasing digestible Thr:Lys ratios promoted linear increase in threonine intake and feed conversion ratio (p<0.05), and a linear decrease in weight gain. The estimated digestible Thr:Lys ratios recommended for meat-type quails are 0.85, 0.73 and 0.66%, for the pre-starter, starter and grower I phases, respectively.

ABSTRACT The poultry market has changed due to a higher consumer interest on products with differentiated organoleptic characteristics, making of free-range broiler production a promising activity. This experiment was conducted to determine the digestible lysine requirements of Redbro Cou Nu male and female chickens during the starter phase (one to 21 days of age). Six hundred and thirty Redbro Cou Nu broilers were distributed into 30 pens (21 chickens/pen) according to a randomized complete design in a 5 x 2 factorial arrangement, consisting of five levels of digestible lysine and two sexes, with three replicates (pens) per treatments. Diets with increasing digestible lysine levels (8.1, 9.5, 10.9, 12.3 and 13.7 g of digestible lysine per kg of diet) were offered ad libitum. The following performance traits were evaluated at the end of the experiment (d 21): feed intake, lysine intake, body weight gain, and feed conversion ratio. No interaction between dietary lysine level and sex was observed for the evaluated traits. The effect of sex was only detected on body weight gain, while effects of dietary lysine level were only detected on the feed intake. Males presented higher body weight gain than females. Lysine intake and body weight gain increased, and feed conversion ratio decreased as the level of dietary lysine increased. The best feed conversion ratio was obtained when birds were fed 12.95 g of digestible lysine per kg of diet.

The aim of this work was to compare the efficiency of total (TC) or partial (PC) collection excreta methods to determine metabolizable energy in poultry feeds. A number of 180 12- to 21-day-old broilers were distributed into two treatments of six replicates of 10 birds each. A reference-diet was formulated to supply broiler requirements, and the test-diets consisted of 60% of reference diets and 40% of corn or soybean meal. Celite was added at 1% to the diets as a marker. Excreta and diet samples were analyzed for dry matter, energy, nitrogen, and acid-insoluble ash (AIA). AME of corn determined by partial collection (PC) was higher (3544 kcal/kg) as compared to total collection (TC) (3133 kcal/kg). However, no difference were observed for soybean meal (1797 vs. 1821 kcal/kg) between both methods. Marker recovery rates in the excreta were 101, 111, and 96% for the basal-diet, and the test-diets with corn or soybean meal, respectively. This result indicates the importance of marker recovery rate in the excreta to evaluate feed AME and digestibility.