Digestibilidade total e parcial e balanço nitrogenado em bovinos em pastejo no período das águas recebendo suplementos com nitrogênio não-proteico e/ou proteína verdadeira

Objetivou-se avaliar o efeito de diferentes relações entre proteína verdadeira e nitrogênio não-proteico sobre a digestibilidade, a síntese de proteína microbiana e o balanço de compostos nitrogenados em bovinos em pastejo durante o período das águas. Foram utilizados cinco novilhos mestiços Holandês × Zebu, castrados, com peso vivo inicial de 335±35 kg fistulados no rúmen e no abomaso. Os tratamentos foram: controle (somente pasto); e suplementos com ureia; com 2/3 de compostos nitrogenados oriundos da ureia e 1/3 de compostos nitrogenados oriundos da albumina; com 1/3 de compostos nitrogenados oriundos da ureia e 2/3 de compostos nitrogenados oriundos da albumina; e com albumina. Foram fornecidos 200 g/dia de proteína bruta (PB) a partir dos suplementos. O experimento foi conduzido segundo delineamento em quadrado latino 5 × 5, com cinco períodos experimentais, cada um de 15 dias. A suplementação não afetou os coeficientes de digestibilidade total nem o teor de nutrientes digestíveis totais da dieta; elevou as estimativas do coeficiente de digestibilidade aparente ruminal da PB, que migraram de negativa, no tratamento controle, para positivas, porém não diferentes de zero, nos tratamentos envolvendo suplementação. O fornecimento de suplementos elevou a concentração de nitrogênio amoniacal ruminal. O balanço de compostos nitrogenados aumentou com a suplementação. A substituição de ureia por albumina influenciou de forma cúbica o balanço de compostos nitrogenados, cuja estimativa foi maior para o suplemento com 1/3 de PB oriunda da ureia. A eficiência de síntese microbiana no rúmen não foi influenciada pelo fornecimento ou pela composição dos suplementos. A suplementação de bovinos em pastejo com fontes de compostos nitrogenados degradáveis durante o período das águas amplia a eficiência de uso do pasto, principalmente por ampliar a retenção de compostos nitrogenados no organismo.

Efeitos de dietas com polpa cítrica em substituição ao milho em grãos no concentrado sobre a degradabilidade e a fauna ruminal em bubalinos

Quatro búfalos com cânulas ruminais foram distribuídos aleatoriamente em quadrado latino 4 x 4, compreendendo quatro rações com feno de capim-coastcross (Cynodon dactylon) (50% MS) e níveis crescentes de polpa cítrica peletizada em substituição ao milho em grão moído no concentrado (0, 33, 66 e 100% MS). Foram avaliadas a degradabilidade dos nutrientes e a população de protozoários no rúmen. Houve efeito quadrático da fração solúvel dos nutrientes entre os tratamentos, com valores maiores nos dois extremos. A taxa de degradação da PB do feno e da MS da polpa cítrica apresentou-se linear com aumento da polpa cítrica na ração. As rações contendo polpa cítrica promoveram menores concentrações de Entodinium e número total de ciliados/mL que a dieta só com milho. Houve predominância dos Entodinium nas dietas contendo somente milho ou somente polpa cítrica, enquanto em mistura predominaram os ciliados da subfamília Diplodiniinae. Observou-se efeito de interação da polpa cítrica com o milho, promovendo modificações no metabolismo ruminal, especialmente na solubilidade dos nutrientes, na curva do pH e na composição da fauna.

In-vitro digestibility of the caged laying hen manure at different stocking times

In order to determine the in vitro digestibility of the dry matter, crude protein and gross energy of caged laying hen manure, an experiment was conducted at the Faculdade de Ciências Agrarias e Veterinarias, campus de Jaboticabal, using completely randomized design with four treatments and six replications. The treatments T1, T2, T3 and T4 consisted of manure stocked for 0, 7, 14 and 21-days, respectively. The in vitro digestibility mean values for T1, T2, T3 and T4 were, respectively, 49.25; 51.43; 49.60 and 46.27% for the dry matter, 60.20; 66.90; 59.40 and 49.21% for the crude protein and 57.30; 63.71; 61.17 and 54.50% for the gross energy. The digestibility regression equations for the dry matter, crude protein and gross energy were, respectively: Y = 49.37 + 0.44X - 0.028X2; Y - 60.77 + 1.23X - 0.086X2 and Y = 57.54 + 1.24X - 0.066X2 were Y = digestibility coefficients and X = stocking times.

Influence of condensed tannins from Brazilian semi-arid legumes on ruminal degradability, microbial colonization and ruminal enzymatic activity in Saanen goats

The present study aimed at determining the influence of condensed tannins present in the Brazilian legume species Mimosa hostilis, Mimosa caesalpinifolia and Bauhinia cheilantha on ruminal degradability, microbial colonization and enzymatic activity. Polyethylene glycol (PEG) was used to reduce the astringency and concentration of soluble condensed tannins. Four ruminally-cannulated Saanen goats (60 +/- 8 kg BW) were fed, in two experimental periods, with a hay diet based on the studied legumes treated or non-treated with PEG. Voluntary intake, microbial colonization, DM, CP, NDF, and ruminal degradability of PEG treated and non-treated forage leaves, as well as pH, ammonia and 1,4 P-endoglucanase activity of the rumen content were evaluated. Astringency and soluble tannin concentration of the studied legumes were reduced by approximately 70% and 50%, respectively, with PEG treatment. Average DM intake was higher for the treated diet (16.76 g DM/kg BW/day against 13.06 g DM/kg BW/day). Percentile values for degradation parameters and for potential and effective degradabilities of DM, CP and NDF were also affected by the tannins, but at different intensities. Electron microscopic observations of ruminally-incubated legume leaves showed a more effective microbial colonization of PEG-treated leaves for all legume species. A decrease in pH and an increase in ammonia concentration and in endoglucanase activity in the ruminal content was also observed for PEG-treated diets at all sampling periods. Condensed tannins of the studied legume species have influenced the adhesion conditions, colonization and enzymatic activity of the microbial ecosystem, and consequently the ruminal degradation of the different dietary fractions. For this reason, the reduction in condensed tannin would be of great importance to improve the nutrition of ruminant feeding of these species. (c) 2005 Elsevier B.V. All rights reserved.

In situ degradability of hand harvested or extrusa samples of Tanzania grass (Panicum maximum, Jacq.)

In order to compare the in situ degradability of tanzania grass samples obtained as by extrusa or hand plucked, three ruminal fistulated cows were used in a completely randomized block design with split-plot scheme. Five grams of extrusa or hand harvested grasses were placed in nylon bags rumen incubated during 3, 6, 12, 24, 48, 96 and 120 hours. The degradability of DM, CP, NDF and ADF were, in this sequence, 62.59, 80.88, 50.73 and 46.65%, for hand-harvested grass; and 79.53, 90.97, 71.21 and 65.68%, for extrusa. In situ degradability data of hand harvested samples were not reliable.

Degradabilidade in situ do Capim Panicum maximum cv. Tanzânia Incubado Cortado ou na Forma de Extrusa

The aim of this study was to compare the chemical composition, in vitro dry matter disappearance (IVDMD) and ruminal degradation of Panicum maximum, J. cv. Tanzania samples obtained by clipping (square method) or extrusa collection (animal selection). In the in situ trial, three ruminal fistulated dry crossbred cows, with 499 kg LW, were used in a completely randomized block design with split-plot arrangement design. Five grams of clipped (+/- 2 cm) grass or extrusa samples were placed in nylon bags (7 x 14 cm) and rumen incubated during 3, 6, 12, 24, 48, 96 and 120 hours. The IVDMD and the CP, NDF and ADF content were, respectively, 55.8, 7.6, 81.9 e 43.6%, for the clipped grass and .66.5, 12.1, 78.8 e 39.5%, for the extrusa samples. The potential degradability of DM, C P, NDF and ADF were 62.59, 80.88, 50.73 and 46.65%, for clipped grass; and 79.53, 90.97, 71.21 and 65.68%, for extrusa samples. The quality of the selected animal diet (extrusa) was better than the available forage in terms of IVDMD and chemical composition (high protein and low fiber content). In situ degradability trials carried out with clipped samples, and non selected by animal, could not supply reliable results closed to the animal diet.

Degradação ruminal de silagem de capim-elefante com adição de vagem de algaroba triturada

This research was carried out to evaluate the ruminal degradation of dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) of silages of elephant grass (Pennisetum purpureum) cutting in 70; 90 and 110 days after regrowth with inclusion of 0; 5; 10 and 15% of mesquite (Prosopis juliflora) meal, based on natural matter in a completely randomized design, in split plot arrangement. Samples of silages were incubated in the rumen of two Jersey cows for 3; 6; 12; 24; 48; 72 and 96 h, and the bags at time "zero" were only washed with water to determine the soluble fraction. There was not interaction (P> 0.05) incubation time x inclusion of mesquite pods x cutting age of the grass for DM degradability, there was only interaction (P <0.05) between these factors for CP and NDF degradability. The most effective DM degradability (42.54%) was observed for 15% inclusion of mesquite pods. The effective CP degradability was higher (69.04%) for elephant grass silage with 70 days after regrowth with 15% of mesquite pods. The inclusion of mesquite pods in elephant grass silages improve DM, CP and NDF degradability, while increment of the age after regrowth result in reduction of this parameters.

Determination of cobalt marker in cow ruminal fluid by EDXRF and SRTXRF

This article describes a comparison of conventional energy-dispersive X-ray fluorescence (EDXRF) and synchrotron radiation total-reflection X-ray fluorescence (SRTXRF) for Co determination in ruminal fluid from Holstein cow. This element is used as marker for animal nutrition studies. For EDXRF, 200 mu l of the sample were dried on 6.35 mu m Mylar filmat 60 degrees C. The excitation was carried out using an X-ray tube with Mo target and Zr filter operated at 30 kV/ 20 mA. For SRTXRF, 10 mu l of the samplewere pipetted on a Lucite carrier and dried at 60 degrees C. In both the techniques, Ga was used as internal standard and the acquisition time was 200 s. The trueness of both techniques was evaluated through the standard addition method, the recoveries obtained by SRTXRF and EDXRF were 76 and 99%, and the limits of detection, 13 and 240 mu g l(-1), respectively. Copyright (C) 2011 John Wiley & Sons, Ltd.

Apparent digestibility of protein, energy, and amino acids in some selected feed ingredients for pacu Piaractus mesopotamicus

The apparent digestibility coefficients (ADCs) of amino acids (AA), protein, and energy in six feed ingredients (Brazilian fish meal, soybean meal, corn gluten meal, alcoholic yeast, corn, and wheat bran) we evaluated for pacu juveniles. In general, all ingredients showed high digestibility values for all AA, and differences among ADCs of individual amino acid were detected (P < 0.01). Corn gluten, soybean, and fish meals had the highest ADCs of AA. The ADCs of protein in fish meal, yeast, and corn gluten meal should not be used as AA digestibility indicators, because those showed differences up to 6.7% between the ADCs of protein and AA. All ingredients had lower ADCs of energy than corn gluten meal (P < 0.01). Lysine was the first limiting amino acid in fish meal, corn gluten meal, wheat bran, and corn, and the second limiting amino acid in soybean meal, as methionine was the first limiting amino acid in soybean meal and yeast. However, the soybean meal was the best quality protein source, as it had the highest digestible essential amino acid index. This demonstrated that digestible amino acid values can be used to formulate practical diets for pacu, preventing potential deficiencies or excess that might cause environmental and economic losses.