-The objective of this study was to evaluate the mass of the forage and of the morphological components, and the sward structure in Piata palisadegrass (Brachiaria brizantha cv. Piata) deferred in function of different initial heights and nitrogen levels. Two levels of nitrogen (75 and 150 kg/ha) and one control without fertilization associated to three initial deferring heights (20, 30, and 40 cm) were evaluated. The design was of completely randomized blocks with three replications in a subdivided plot scheme. A raise in the initial deferment height and in the fertilization elevated the sward and extended tiller heights, the leaf area index, and the light interception by the sward. The piata palisadegrass deferred with an initial height of 40 cm presented a higher forage mass with lower percentage of leaf blades, and higher stem and dead tissue quantity.Additionally, this management strategy resulted in lower bulk density of leaf blade and in higher bulk densities of stems and dead tissue. The utilization of 150 kg/ha of nitrogen raised the production and the bulk density of deferred piata palisadegrass forage and increased production and bulk density of leaves and stems. In the region of Viçosa, Minas Gerais, the piata palisadegrass deferred with an initial height of 30 cm and fertilized with 75 kg/ha of nitrogen in the beginning of the fall presents adequate mass and structure to animal production in the winter.

Three experiments were conducted to evaluate the effect of β-mannanase (BM) supplementation on the performance, metabolizable energy, amino acid digestibility, and immune function of broilers. A total of 1,600 broilers were randomly distributed in a 4 × 2 factorial arrangement (4 nutritional levels × 0 or 500 g/ton BM), with 10 replicates and 20 broilers per pen. The same design was used in the energy and digestibility experiments with 8 and 6 replicates, respectively, and 6 broilers per pen. The nutritional levels (NL) were formulated to meet the nutritional requirements of broilers (NL1); reductions of 100 kcal metabolizable energy (NL2); 3% of the total amino acids (NL3); and 100 kcal metabolizable energy and 3% total amino acids (NL4) from NL1. The serum immunoglobulin (Ig) concentration was determined in two broilers per pen, and these broilers were slaughtered to determine the relative weight of spleen, thymus, and bursa of Fabricius. Throughout the experiment, the lower nutritional levels reduced (P < 0.05) body weight gain (BWG) and increased (P < 0.05) feed conversion (FCR) for the NL4 treatment. The BM increased (P < 0.05) the BWG values and improved (P < 0.05) the FCR of the broilers. The apparent metabolizable energy corrected for nitrogen balance (AMEn) values were reduced (P < 0.05) for NL2 and NL3. The BM increased (P < 0.05) the AMEn values and reduced (P < 0.05) the excreted nitrogen. NL3 and NL4 reduced (P < 0.05) the true ileal digestibility coefficients (TIDc) of the amino acids cystine and glycine, and BM increased (P < 0.05) the TIDc for all amino acids. The addition of BM reduced (P < 0.05) the relative weights of the spleen and bursa. NL2 increased (P < 0.05) the Ig values, whereas BM reduced (P < 0.05) the serum IgA, IgG, and IgM values of the broilers. This study indicates that using suboptimal nutrient levels leads to losses in production parameters, whereas BM-supplemented diets were effective in improving performance, energy values, and TIDc levels of amino acids and immune response of broilers.

-The objective of this study was to determine the deferment period and the most adequate initial sward height of Brachiaria brizantha cv. Piatã for deferment in the region of Viçosa, Minas Gerais. For so, the following characteristics were evaluated: masses and bulk density of forage and its morphological components, light interception by the sward, leaf area index, leaf angle, sward and extended tiller height and falling index of the deferred piatã grass. The three deferment periods assessed (65, 85 and 105 days) were randomized to the plots and the three sward heights (20, 30 and 40 cm), randomized in the subplots. The experimental design was of completely randomized blocks, with three replicates, in a subdivided plots arrangement. Masses of forage, green stem and dead tissue were higher in the piatã grass managed with deferment period of 105 days. The mass of green leaf blade was higher in the piatã grass deferred with 20 cm height associated to the deferment period of 85 days, which had, as consequence, greater bulk density of green leaf blade. The interception of light by the sward was greater in the piatã grass kept longer in deferment associated with the higher leaf area index, regardless of its initial height.The heights of the sward and extended tillers were greater in the piatã grass under periods of 85 and 105 days of deferment; however, the falling index was not affected by the factors studied. In the region of Viçosa, Minas Gerais, B. brizantha cv. Piatã fertilized with 75 kg/ha nitrogen and deferred with initial height of 20 cm and for a period of 85 days, from mid April, has adequate productivity and structure for animal production.

No abstract

This study was undertaken to evaluate the effects of dietary calcium levels and supplementation with organic trace minerals selenium, copper, iron, zinc and manganese on performance, tissue deposition and litter mineral concentration. A total of 2,496 one-day-old male Cobb 500 broilers were randomly assigned to a 3 × 4 factorial experimental design with three levels of dietary Ca [8, 10 and 12 g kg-1 , while maintaining the same Ca:nPP (non-phytate phosphorus) ratio (2:1)] and four levels of micromineral supplementation (0.62, 0.72, 0.82 and 0.92 g kg-1). There was a total of 12 treatments, with eight replicates of 26 birds per pen. Micromineral supplementation (MS) was achieved by adding different levels of the product Bioplex TR Se ® and Ca supplementation was achieved by adding increasing levels of limestone and dicalcium phosphate. An interaction between Ca and MS levels was observed (p < 0.05) for the parameters of performance, liver Cu concentration, breast Se and Cu concentrations and litter Se, Mn and Zn concentrations. No interactions were observed (p > 0.05) for Ca, P or ash concentrations in the tibia, which were influenced only by dietary Ca levels (p < 0.05). The Ca level of 10 g kg-1 promoted higher Ca and P concentration in the tibia and lower micromineral excretion in the litter. The combination of MS level of 0.82 g kg-1 with Ca level of 10 g kg-1 led to the best BWG response. The supplementation conditions that led to higher micromineral levels in the liver and breast varied for each mineral.

Dois experimentos foram realizados na Unidade de Ensino, Pesquisa e Extensão em Produção e Nutrição de Suínos da Universidade Federal de Viçosa com os objetivos de determinar a exigência de lisina digestível para suínos machos castrados em crescimento, através da exigência diária de nitrogênio para mantença, máxima retenção diária de nitrogênio, utilizando o método de balanço de nitrogênio e, determinar a relação ótima dos aminoácidos essenciais para suínos machos castrados em crescimento, por meio do método de deleção. Ambos os experimentos utilizaram modelos matemáticos do método de Göettingen. No primeiro experimento foram realizados dois ensaios de balanço de nitrogênio, para animais com peso médio de 25,20±0,24 kg e 56,08±0,67 kg, respectivamente. Para cada ensaio foram utilizados 24 suínos machos castrados (Camborough x AGPIC 337), totalizando 48 animais, alojados individualmente em gaiolas de metabolismo. Foi formulada uma dieta concentrada (N6) à base de milho, farelo de soja e glúten de milho, com 27,0% de PB, 1,585% de lisina digestível e 3230 kcal de EM e uma dieta isenta em proteína (DIP) à base de amido de milho utilizada para diluir a dieta concentrada, através da técnica da diluição e assim compor os tratamentos com diferentes níveis de proteína bruta (N1 a N5): 6,22; 10,37; 14,53; 18,69 e 22,84% e com 0,365; 0,609; 0,853; 1,097 e 1,341% de lisina digestível, respectivamente. Cada ensaio consistiu em cinco dias de período de adaptação e dois períodos de cinco dias de coletas de fezes e urina. Para suínos com peso médio de 25 kg os valores de NMR, ND max T e a exigência de lisina digestível considerando 60% do ND max T foram, respectivamente, 170,32 mg/PC kg0,75 /d, 3322,38 mg/PC kg0,75 /d e 1,236%. Para os animais com peso médio de 56 kg os resultados para NMR, ND max T e a exigência de lisina considerando 80% do ND max T foram, respectivamente, 204,31 mg/PC kg0,75 /d, 1667,45 mg/PC kg0,75 /d e 0,900%. No segundo experimento, foram realizados dois ensaios de balanço de nitrogênio, com suínos machos castrados (Camborough x AGPIC 337) de 23,81±2,39 kg e 59,48±0,93 kg. Em cada um dos ensaios foram utilizados 11 tratamentos com duas repetições, dois períodos consecutivos de coletas e um animal por gaiola, totalizando 4 repetições com 22 animais por ensaio. Uma dieta balanceada (DB) foi formulada para atender as exigências de todos os nutrientes. As outras dietas foram formuladas de forma a deletar 30% o aminoácido (AA) testado em cada tratamento. Cada ensaio consistiu em cinco dias de período de adaptação e 10 dias de coletas de fezes e urina (cinco dias em cada período). Para obter a relação ideal dos aminoácidos (RIAA) foram considerados os valores de bc -1 (eficiência de utilização do aminoácido limitante). A RIAA para suínos com peso médio de 25 kg foi Lis 100%, Met+Cis 57%, Treo 63%, Trip 18%, Arg 49%, Val 67%, Ile 57%, Leu 109%, Fen+Tir 112% e His 30%. Para suínos com peso médio de 60 kg, a RIAA foi Lis 100%, Met+Cis 57%, Treo 63%, Trip 23%, Arg 55%, Val 63%, Ile 56%, Leu 109%, Fen+Tir 118% e His 33%. Palavras-chave: Aminoácido. Balanço de nitrogênio. Diluição. Deleção. Suínos.