Tatiana Cristina da Rocha

Níveis de lisina digestível em rações para poedeiras no período de 24 a 40 semanas de idade

The objective of this study wast to determine the requirement of digestible lysine for light-weight laying hens 24 to 40 weeks of age. Two hundred and sixteen Hy-Line W36 light-weight laying hens were allotted to a randomized complete blocks with six treatments, six blocks and six hens per experimental unit. The treatments consisted of a basal diet, with 14.54% crude protein, deficient in digestible lysine (0.545%), supplemented with six levels of L-lysine HCl (78%) 0.00; 0.059; 0.118; 0.177; 0.237 and 0.295%. Considering the digestibility of the lysine to be 97.6%, the amount of L-lysine. HCl added in each diet supplied 0.00; 0.045; 0.090; 0.135; 0.180 and 0.225 digestible lysine, respectively, resulting in diets with 0.545; 0.590; 0.635; 0.680; 0.725 and 0.770% digestible lysine. Feed intake, lysine intake, egg production, average egg weight, egg mass, feed conversion (kg feed/egg dozen), albumen index and final weight gain of the chickens showed a linear response with increase in the digestible lysine levels. There was a quadratic effect for the levels of digestible lysine on feed conversion/egg mass but no significant effect on Haugh Units, yolk index and egg components was detected. The digestible lysine requirement was estimated to be at least 0.770% of the diet, corresponding to the intake of 759 mg of lysine digestible/hen/day.

Níveis de metionina + cistina digestível para poedeiras leves no período de 42 a 58 semanas de idade

Aiming at determining levels of digestible sulfurous amino acids to establish the ideal methionine + cystine/lysine relationship in rations for light-weight laying hens in the period from 42 to 58 weeks of age, 216 birds of the commercial brand Hy- Line W36 were distributed in a randomized block design with 6 diets, 6 repetitions and 6 birds per experimental unit. The level of digestible lysine used in the experimental diet was 0.770% for an expected average consumption of 731 mg/hen/day of lysine and 95 g/hen/day of ration. Levels of digestible sulfurous amino acids were obtained from a basal diet deficient in digestible methionine + cystine (0.65%), supplemented with 0.00; 0.05, 0.10, 0.15, 0.20 and 0.25% of DL-methionine (99.2%), so to provide a methionine + cystine/lysine relationship of 84, 91, 97, 104, 110 and 117%. The experimental period lasted for 16 weeks and it was subdivided in 4 cycles of egg collection, each one corresponding to 28 days. There was a quadratic effect of the digestible methionine + cistine levels of 0.826% and 0.775% on the egg production and lysine utilization efficiency for total egg production, respectively. The digestible methionine + cystine level considered as a requirement for light-weight laying hens in the period from 42 to 58 weeks of age were 0.775%, corresponding to digestible methionine + cystine consumption of 708 mg/hen/day, and a methionine + cystine/lysine relationship of 101%.

Exigência nutricional de lisina para codornas européias machos de 21 a 49 dias de idade

The trial was carried out to estimate the requirements of total lysine for male European quails (Coturnix coturnix coturnix) from 21 to 49 days old. Three hundred and fifteen quails averaging 80 g BW were fed diets with corn, soy crumb and corn gluten crumb. The basal diet was not supplementated with L-lysine, containing 20% of crude protein, 2,900 kcal of energy metabolizable/kg and 0.9% of total lysine, supplemented with 0.125, 0.231, 0.357, and 0.483 g of L-lysine (79%), resulting in 1.0, 1.1, 1.2, and 1.3% of total lysine, respectively. The trial was analyzed as a completely randomized experimental design with five treatments, seven replicates and nine birds per experimental unit. The following variables were studied: feeding intake, final body weight, body weight gain, feed:gain ratio, productive efficiency index, breast yield and carcass. No significant effect was observed for all the variables. It concluded that the dietary total lysine requirement is of 0.9% for male European quails from 21 to 49 days old, corresponding to a daily intake of 207 mg of lysine.

Níveis de metionina+cistina digestível em rações para poedeiras leves no período de 24 a 40 semanas de idade

The objective of this work was to determine digestible sulfurous amino acids levels to establish the ideal methionine+cystine:lysine relationships in meals of light-weight laying hens in the period from 24 to 40 weeks of age. It was used 216 Hy-Line W36 birds distributed in a randomized block design with 6 levels each one with 6 repetitions and 6 birds per experimental unit. The digestible sulfurous amino acids levels were obtained from a basal diet with low levels of digestible metionin+cistine (0.65%) supplemented with 0.00; 0.05; 0.10; 0.15; 0.20 and 0.25% of DL-methionine (99.2%) to provide a relationship methionine+cystine:lysine of 84, 91, 97, 104, 110 and 117%. The experimental period lasted 16 weeks and it was subdivided in 4 subperiods of collection of the eggs, each one corresponding to 28 days. Levels of digestible methionine+cistine affected egg production and lysine utilization efficiency per total egg production, reaching a plateau in 0.811 and 0.772% of digestible methionine+cistine, respectively. The digestible methionine+cystine level considered as a requirement for light-weight laying hens in the period from 24 to 40 weeks of age is of 0.772%, corresponding to digestible methionine+cystine consumption of 682 mg/hen/day, and the relationship methionine+cystine:lysine of 100%.

Digestible tryptophan:digestible lysine ratio in diets for laying hens from 24 to 40 weeks of age

The objective of this study was to determine the ideal digestible tryptophan:digestible lysine ratio in diets for laying hens from 24 to 40 weeks of age. Two hundred and forty Hy-Line W-36 laying hens at 24 weeks of age were distributed in a completely randomized design, with five treatments, eight replicates and six birds per experimental unit. The digestible tryptophan levels in the experimental diets were 1.57; 1.68; 1.79; 1.90 and 2.01 g/kg, providing ratios of digestible tryptophan:digestible lysine of 0.215; 0.230; 0.245; 0.260 and 0.275. The increase in the levels of digestible tryptophan in the diet linearly improved the feed intake, digestible tryptophan intake, digestible lysine intake, egg production, egg mass, feed conversion per egg mass and utilization efficiency of digestible lysine for eggs mass. There were quadratic effects from the digestible tryptophan levels on egg weight. For the efficiency of utilization of digestible lysine for egg mass, there was better adjustment of the data to the LRP model. The level of digestible tryptophan in the diet from which the plateau occurred was 0.184%. This level corresponded to the intake of 142 mg/bird/day of digestible tryptophan and digestible tryptophan:digestible lysine ratio of 0.252. The ideal digestible tryptophan:digestible lysine ratio recommended in diets for laying hens from 24 to 40 weeks of age is 0.252 (25.2%).

Digestible threonine to lysine ratio in diets for laying hens aged 24-40 weeks

Two-hundred sixteen white laying hens were used to assess the ideal ratio of digestible threonine:lysine in diets for laying hens at 24 to 40 weeks of age. Birds were assigned to a randomized block design, with six treatments, six replicates per treatment and six birds per experimental unit. The cage was used as the blocking criterion. Experimental diets contained different digestible threonine:digestible lysine ratios (65, 70, 75, 80, 85 and 90%) with 142 g/kg of crude protein. Experimental diets were formulated to be isonitrogenous and isocaloric with different contents of L-glutamic acid. Feed intake (g/hen/d), egg production (%), egg weight (g), egg mass (g/hen/d), feed conversion ratio (kg/dozen and kg/kg egg), eggshell weight (g), albumen weight (g), yolk weight (g) and body weight gain (g) were assessed. The maximum egg production was observed at 78% digestible threonine:digestible lysine ratio, while the best values of feed conversion ratio (kg/dozen egg) and feed conversion ratio (kg/kg of egg) were observed at 77.6% and 75%, respectively. Feed intake, egg mass and egg contents (yolk, albumen and eggshell) were not affected by treatments. The estimated digestible threonine:digestible lysine ratio of Hy-Line W36 laying hens at 24 to 40 weeks of age is 78%, corresponding to 5.70 g/kg of dietary digestible threonine.

Determination of digestible isoleucine: lysine ratio in diets for laying hens aged 42-58 weeks

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 diet was supplemented with L-isoleucine to make up the 6 diets. Each diet was made isonitrogenous by varying the dietary contents of glutamic acid and isocaloric by adjusting the contents of cornstarch. All essential amino acids were provided proportionally to lysine. Egg production, egg weight, egg mass, feed conversion ratio, albumen, yolk and eggshell contents were recorded and compiled at every 28-day period. No differences were observed in the performance over a wide range of dietary isoleucine concentrations from 5.76 to 7.73 g/kg corresponding to 0.73:1 to 0.98:1 Ile:Lys ratios. The lowest Ile:Lys ratio (0.73:1) was sufficient to ensure satisfactory performance of birds, corresponding to the consumption of 534 mg of isoleucine and 731 mg of lysine/day.

Ideal digestible isoleucine: digestible lysine ratio in diets for laying hens aged 24-40 weeks

Two hundred fifty-two Hy-Line W36 laying hens were allotted in a randomized block design with 6 treatments, 7 replicates and 6 hens per experimental unit in order to determine the ideal digestible isoleucine: digestible lysine (Ile:Lys) ratio for laying hens aged 24-40 weeks. Experimental diets contained 5.92, 6.33, 6.73, 7.14, 7.54 and 7.95 g/kg of digestible isoleucine, 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). Experimental diets were isonitrogenous, with different dietary contents of glutamic acid, and made isocaloric by adjusting the levels of cornstarch. All essential amino acids were provided proportionally to digestible lysine. Feed intake, egg production, egg weight, egg mass, feed conversion ratio per egg mass, feed conversion ratio per dozen eggs, albumen, yolk and eggshell content were assessed. Feed intake, egg production, egg mass and feed conversion ratio were influenced by Ile: Lys ratios quadratically. The egg weight was not affected by Ile: Lys ratio. No differences were observed in the egg quality according to Ile: Lys ratios. The data indicates that the optimum digestible isoleucine: digestible lysine ratio for laying hens aged 24-40 week is 0.84:1, corresponding to the consumption of 681 mg of isoleucine and 811 mg of lysine/hen day-1.

Requirement of available phosphorus by female broiler chickens keeping the calcium:available phosphorus ratio at 2:1

Four trials were conducted to determine the requirements of available phosphorus (aP) of female broiler chicks from 1 to 10 (exp.1), 11 to 21 (exp.2), 22 to 33 (exp.3), and from 34 to 46 (exp.4) days of age, keeping the calcium:available phosphorus ratio equal to 2:1. In each trial, 480 Cobb broilers were randomly allotted in a completely randomized design with 6 treatments, 8 replicates and 10 birds per pen. The levels of aP ranged from 2.0 to 5.5 g/kg (Exp. 1), 1.9 to 5.4g/kg (exp. 2), 1.8 to 5.3 g/kg (exp. 3) and 1.7 to 5.2 g/kg of diet (exp. 4), in increments of 0.7 g/kg. The experimental diets were formulated using corn and soybean meal and the available phosphorus was considered 33% of total phosphorus. The characteristics evaluated were body weight gain, feed intake, feed conversion ratio and bone parameters. For female broiler chicks from 1 to 10; 11 to 21; 22 to 33; and from 34 to 46 days of age, the levels of available phosphorus and calcium recommended are 4.59 and 9.18; 3.88 and 7.76; 3.58 and 7.16; and 2.56 and 5.12 g/kg of diet, respectively.

Composição química e energética de alimentos para frangos de corte

The aim of this work was to determine the chemical composition and values for apparent metabolisable energy (AME), and apparent metabolizable energy corrected for nitrogen (AMEn), in broiler feeds. In the experiment, 432 male broiler chicks, 14 to 24 days old were used, distributed in a completely randomised design with 12 treatments (11 feeds and a reference diet), six replications and six birds per experimental unit. The method employed was the total collection of excreta. The feeds under study were: Two of viscera meal (VM), two feather and blood meal (FBM), two meat and bone meal (MBM), roasted whole soybean (RWS), soybean meal (SM), ground corn (GC), wheat bran (WB) and millet (M). The values for crude protein and ether extract (%), AME and AMEn (kcal/kg) were respectively: 58.84, 12.64, 3705 and 3340 for VM1; 57.64, 11.66, 3565 and 3241 for VM 2; 80.58, 6.79, 3070 2740 for FBM 1; 82.27, 6.38, 3060 2703 for FBM 2; 48.06, 9.60, 1574 and 1283 for MBM 1; 41.21, 9.08, 1353 and 1088 for MBM 2; 36.45, 20.78, 3192 and 2989 for RWS; 46.22, 1.72, 2648 and 2336 for SM; 8.51, 3.61, 3354 and 3265 for GC; 17.11, 3.14, 1948 and 1788 and for WB; and 12.01, 4.09, 3072 and 2948 for M. The differences found in chemical and energy composition highlight the need for research to revise the nutritional values of feed.