The objective of this experiment was to establish different criteria to evaluate the requirements of digestible tryptophan for broilers from 22 to 42 d of age, using different regression models (quadratic, exponential and Linear Response Plateau) and in case of statistical significance the comparison of means by Duncan test at 5% probability was also adopted. A total of 1,920 Cobb 500 male broilers were distributed in a completely randomized experimental design, with 6 treatments (6 digestible tryptophan levels: 0.1395, 0.1610, […]

The objective of this study was to estimate the digestible lysine requirement of Japanese quails in the egg-laying phase. A total of 336 female Japanese quails (Coturnix coturnix japonica) of average initial age of 207 days were distributed in a completely randomized experimental design, composed of 6 treatments (lysine levels) with 7 replicates and 8 birds per experimental unit, with duration of 84 days. Experimental diets were formulated from a basal diet, with corn and soybean meal, with 2.800 kcal […]

The objective of this experiment was to evaluate the effect of two digestible lysine levels and four digestible arginine levels on laying hens from 24 to 48 weeks of age. Three hundred and twenty Lohmann LSL laying hens were allotted in a completely randomized design in a 2 × 4 factorial arrangement, with two levels of digestible lysine (700 and 900 mg/kg of diet) and four digestible arginine levels (700, 800, 900 and 1000 mg/kg of diet). Results indicated requirement […]

Two hundred and fifty-two Hy-Line W36 laying hens were allotted in a completely randomized design with 6 treatments, 7 replicates and 6 hens per experimental unit in order to determine the ideal ratio of isoleucine (Ile) in relation to lysine (Lys) to laying hens aged 42-58 weeks. Experimental diets contained digestible Ile at different levels, resulting in different Ile:Lys ratios (0.73:1; 0.78:1; 0.83:1; 0.88:1; 0.93:1 and 0.98:1). A basal diet was formulated to provide Isoleucine in levels below recommendations. This […]

The objective of this study was to determine the coefficients of apparent and true digestibility of protein and amino acids of five feedstuffs (corn, wheat bran, soybean meal, corn gluten meal and fish meal) in 900 sex-reversed Nile tilapia (Oreochromis niloticus) of the Thai strain during the growth phase, with an initial weight of 315±8.45 g. A total of 750 fish were distributed according to a randomized block design (repetitions in time) into five treatments with six replicates of 25 […]

The objective of this experiment was to establish different criteria for evaluation of the requirements of digestible threonine for broilers from 22 to 42 d of age, using different regression models (quadratic, exponential, and Linear Response Plateau). A total of 1,920 22-day-old male Cobb broilers were distributed in randomized experimental design, with six treatments (six threonine levels: 0.5904, 0.6441, 0.6977, 0.7514, 0.8051, and 0.8588%) and 8 replications containing 40 broilers each one. The level of 0.6977% digestible threonine was used […]

Chemical and amino acid composition and true digestibility coefficients of amino acids of feather and blood meals for birds from different suppliers were determined. Thirty cecectomized cocks were distributed in a completely randomized design, with 4 different feather and blood meals (meals 1, 2, 3 and 4) and one treatment in which the birds remained fasting, with six replications as the experimental unit composed of one rooster. The variations in the chemical composition of the feather and blood meals can […]

A total of 3,760 Ross male broiler chicks were used in two trials, one in the pre-starter (1-11 days) phase and the other in the starter (12-22 days) phase. Birds were distributed in a completely randomized experimental design with a factorial arrangement of 5 digestible lysine levels × 2 environments (clean and dirty environment), with eight replicates per treatment. The following dietary digestible lysine levels used were: 1.06, 1.12, 1.18, 1.24 and 1.30% in the pre-starter phase, and 1.00, 1.06, […]

This work evaluated levels of digestible lysine on performance and carcass composition of barrows with high genetic potential for meat deposition. It was used 80 animals with initial body weight of 95.55 ± 1.04 kg, distributed in a completely randomized block design, with 5 diets (0.540; 0.642; 0.744; 0.846 and 0.948% of digestible lysine), eight replicates and two animals per experimental unit. The experimental diets and water were provided ad libitum throughout the experimental period. Digestible lysine levels did not […]

The objective of this work was to estimate requirements of digestible methionine + cystine for broiler chickens from 1 to 42 days of age. It was carried out four experiments for each one of the following phases: pre-initial, initial, growing and final. The birds were distributed in a completely randomized experimental design, with six treatments and six replicates. Treatments consisted of a basal feed for each phase, deficient in digestible methionine + cystine and supplemented with DL-methionine to supply six […]