Markers in cattle omasal digesta collection and gastrointestinal tract flow kinetics

Autor: Dias, Marcia
Přispěvatelé: Detmann, Edenio, Valadares Filho, Sebastião de Campos, Leão, Maria Ignez, Saliba, Eloísa de Oliveira Simões, Valadares, Rilene Ferreira Diniz
Jazyk: portugalština
Rok vydání: 2009
Předmět:
Zdroj: LOCUS Repositório Institucional da UFV
Universidade Federal de Viçosa (UFV)
instacron:UFV
Popis: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior It was aimed to evaluate markers and markers systems in omasal digesta collection; to compare the estimate of particles and fluids flow kinetics by different markers and mathematical models; to evaluate the estimate of the flow rate by ruminal emptying technique and by the no-linear mathematical model adjustment; using two roughages (sugarcane and corn silage) and two concentrate levels (0 and 25%) in heifers diet. Three experiments were conducted. In the first experiment, four rumen fistulated Nelore heifers were used, which were confined, fed Tifton-grass (Cynodon spp.) hay ad libitum and 1 kg of concentrate (16% CP) for 32 days, with four periods of four days each. The adaptation to the experimental diet was of seven days and interval of three days between the periods. The four treatments evaluated consisted of four Co-EDTA and YbCl3 infusion times in different omasal digesta phases: one (T1v), two (T2v), four (T4v) and six (T6v) times a day with the same intervals. The times of omasal digesta collection comprehended a period of 24 hours and interval of two hours. The nictimeral profile was determined by the Fourier series model. The Co and Yb average concentration did not differ (P>0.05) among the different infusion times and omasal digesta phases, presenting variation index inferior to 10%. The variation index and the oscillation amplitude for both indicators went smaller for T4v. The variation index were inferior to 10%, with smaller values for iNDF (0.66-2.07%), iADF (1.16-4.46%) and LIPE (0.64- 2.96%) and greater for Cr2O3 (2.52-9.64%) and TiO2 (2.75- 3.49%). Comparing the fundamental dimension of the excretory cycle (c) in omasal digesta phases, excepting the liquid phase, the best values (P0.05) of the collection period on omasal and ileal flows. The omasal flow was better estimated by iNDF, iADF and associations with the Co-EDTA and YbCl3. In the third and last experiment, four Holstein-Zebu heifers fistulated in rumen and ileum were used in a 4x4 Latin square. The diets consisted of a 2x2 factorial, with two roughages (sugarcane and corn silage) and two concentrate levels (0 and 25% of total diet DM). From the 8th to the 14th day the estimate of digesta flow was estimated with markers, the chrome (Cr) mordent fiber and complexed with európio (Eu) and ytterbium (Yb) to mark the solid phase of the roughages, and the cobalt-etilenodiaminotetracetic acid (Co-EDTA) for the liquid. In the 8th day, collection of ruminal liquid was done and, from the 14th to the 16th day, ruminal emptying. The curves of concentration of solid phase indicators were adjusted to the multicompartimental (G1(n) → 0) and bi-compartimental (G2 → G1 → 0) models and of fluids to the time-independent (G1 →) and time-dependent (G2 →) uni-compartimental models. The k2 of the multi-compartimental model was approximately the double of that of the bi-compartimental model, while the k1 were similar. Both in the multi as in the bi-compartimental models, the use of Yb resulted in the least behavior and uniformity of the points among the evaluated markers, while Cr was the one which best represented the data of solids passage rate. Comparing the models, the multicompartimental model was better than the bi-compartimental. The models evaluated for fluids passage rate presented similar behavior, but the asymptotic standard deviation was smaller for the time-dependent model. Chrome and Co-EDTA were good indicators to evaluate particles and fluids passage rate, respectively. The models recommended for particles passage rate was the multi-compartimental (G1(n) → 0) and, for fluids, the time-dependent unicompartimental (G2 →). This way, the diets and the methods of estimate particles passage rate were compared using these indicators and models. Greater (P0.05) of the roughage on ruminal mass, but the concentrate addition reduced (P0,05) entre os diferentes tempos de infusão e fases da digesta omasal, apresentando índice de variação inferior a 10%. O índice de variação e a amplitude de oscilação para ambos os indicadores foram menores para o T4v. Os índices de variação foram inferiores a 10%, com menores valores para a FDNi (0,66-2,07%), FDAi (1,16-4,46%) e LIPE® (0,64- 2,96%) e maiores para Cr2O3 (2,52-9,64%) e TiO2 (2,75- 3,49%). Comparando a dimensão fundamental do ciclo excretório (c) nas fases da digesta omasal, excetuando a fase líquida (FL), os melhores valores (P0,05) do período de coleta sobre os fluxos omasal e ileal. O fluxo omasal foi melhor estimado pela FDNi, FDAi e associações com o Co-EDTA e o YbCl3. No terceiro e último experimento, utilizaram-se quatro novilhas Holandês-Zebu com fístulas no rúmen e íleo, em quadrado latino 4x4. As dietas consistiram de fatorial 2x2, dois volumosos (cana-de-açúcar e silagem de milho) e dois níveis de concentrado (0 e 25% da MS da dieta total). Do 8º ao 14º dia realizou-se a estimativa de trânsito de digesta com indicadores, a fibra mordantada com cromo (Cr) e complexada com európio (Eu) e itérbio (Yb) para marcar a fase sólida dos volumosos, e o complexo de cobalto-ácido etilenodiaminotetracético (Co-EDTA) para a líquida. No 8º dia foi realizada coleta de líquido ruminal e, do 14º ao 16º dia, esvaziamento ruminal. As curvas de concentração dos indicadores de fase sólida foram ajustadas aos modelos multicompartimental (G1(n) → O) e bicompartimental (G2→ G1→ O) e de fluidos ao modelo unicompartimental tempo- independente (G1 →) e tempo-dependente (G2 →). A k2 do modelo multicompartimental foi aproximadamente o dobro daquela do modelo bicompartimental, enquanto os k1 foram semelhantes. Tanto nos modelos multi como bicompartimental, a utilização do Yb resultou no comportamento gráfico e na uniformidade dos pontos menos adequado dentre os indicadores avaliados, enquanto que o Cr representou melhor os dados da taxa de passagem de sólidos. Comparando os modelos, o modelo multicompartimental foi melhor que o bicompartimental. Os modelos avaliados para a taxa de passagem de fluidos apresentaram comportamento semelhante, mas o desvio-padrão assintótico foi menor para o modelo tempodependente. O cromo e o Co-EDTA foram bons indicadores para avaliação da taxa de passagem de partículas e fluidos, respectivamente. Os modelos recomendados para a taxa de passagem de partículas foi o multicompartimental (G1 (n) → 0) e para fluidos o unicompartimental tempo- dependente (G2 →). Desta forma, compararam-se as dietas e os métodos de estimação da taxa de passagem de partículas utilizando esses indicadores e modelos. Foi verificado maior (P0,05) do volumoso sobre a massa ruminal, mas a adição de concentrado reduziu (P
Databáze: OpenAIRE
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