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Effect of cereal type and commensal bacteria on availability of methionine sources and intestinal physiology in pigsMalik, Gita 21 September 2009
An investigation was conducted to determine the contribution of the gastrointestinal microbiota to variation in bioefficacy of methionine sources and the interrelationship between intestinal microbiota and cereal grain type with respect to gastrointestinal physiology. Apparent gastrointestinal absorption of DL-methionine (MET) and 2-hydroxy-4-methylthiobutanoic acid (MHA-FA), post-weaning intestinal morphology, digestive physiology, mucin dynamics and digesta flow were studied in a series of experiments using conventional and gnotobiotic pigs. At 14 d of age, sow - reared conventional (CON) pigs and isolator - reared monoassociated gnotobiotic pigs (EF) were weaned to corn or wheat/barley based diets supplemented with MET or MHA-FA. At 24 d of age, after an overnight fast, pigs were fed experimental diet supplemented with 107 Bq of either 3H-L-MET or 3H-L-MHA-FA per kg of feed and chromic oxide (0.5% wt/wt). Pigs were killed 3 h after consuming the meal to collect digesta and tissue samples from the stomach and along the small intestinal (SI) length. Conventional pigs fed a wheat/barley-based diet had increased (P < 0.05) total aerobes, whereas supplementation with MHA-FA increased (P < 0.05) total aerobes and lactobacilli populations in proximal SI. Among the gnotobiotic pigs, 8 pigs (2 isolators) were monoassociated with a bacteria closely related to <i>Providencia</i> spp. and 16 pigs (4 isolators) were monoassociated with <i>Enterococcus faecium</i> (EF). Species of bacterial contaminant and diet composition did not affect residual MET or MHA-FA in digesta. Decreased (P < 0.05) apparent residual MET in digesta compared with MHA-FA in CON but not monoasscoiated pigs, along with significantly higher (P<0.05) MET associated radioactivity at 5% SI tissue suggested that microbial metabolism of MHA-FA increases its retention in small intestinal digesta and contributes in part to the lower bioefficacy of MHA-FA compared to MET. A comparison of CON and EF pigs showed that wheat/barley diets increased digesta viscosity (<i>P</i> < 0.01) and proliferating cell nuclear antigen (PCNA) expression (<i>P</i> < 0.001) and tended to decrease (<i>P</i> < 0.07) aminopeptidase N (APN) activity. Monoassociation decreased (<i>P</i> < 0.01) body weight, relative spleen weight, crypt depth, PCNA expression, caspase-3 activity, sucrase expression, total goblet cells in crypts and mucin gene expression and increased (<i>P</i> < 0.01) relative SI length, digesta viscosity, villus height, APN and sucrase activity. Interactive effects between cereal grain type and microbial status were observed only as trends (<i>P</i> < 0.1) for PCNA, Muc2, APN and sucrase suggesting these effects were mediated indirectly through microbial changes. Decreased % retained chromic oxide in digesta at all SI locations and no chromic oxide at 95% SI length in monoassociated pigs indicated slower small intestinal transit of digesta in monoassociated pigs. We successfully developed the chromic oxide microassay for estimating chromic oxide in 1/20th of original sample size (2.0 g). Results of this study indicate that microbial metabolism of MHA-FA contributes in part to the lower bioefficacy of MHA-FA compared to MET. Monoassociation had major effects on intestinal physiology whereas limited indirectly mediated effects of cereal type were observed suggesting no major influences of cereal grain type during the short early post-weaning phase.
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Effect of cereal type and commensal bacteria on availability of methionine sources and intestinal physiology in pigsMalik, Gita 21 September 2009 (has links)
An investigation was conducted to determine the contribution of the gastrointestinal microbiota to variation in bioefficacy of methionine sources and the interrelationship between intestinal microbiota and cereal grain type with respect to gastrointestinal physiology. Apparent gastrointestinal absorption of DL-methionine (MET) and 2-hydroxy-4-methylthiobutanoic acid (MHA-FA), post-weaning intestinal morphology, digestive physiology, mucin dynamics and digesta flow were studied in a series of experiments using conventional and gnotobiotic pigs. At 14 d of age, sow - reared conventional (CON) pigs and isolator - reared monoassociated gnotobiotic pigs (EF) were weaned to corn or wheat/barley based diets supplemented with MET or MHA-FA. At 24 d of age, after an overnight fast, pigs were fed experimental diet supplemented with 107 Bq of either 3H-L-MET or 3H-L-MHA-FA per kg of feed and chromic oxide (0.5% wt/wt). Pigs were killed 3 h after consuming the meal to collect digesta and tissue samples from the stomach and along the small intestinal (SI) length. Conventional pigs fed a wheat/barley-based diet had increased (P < 0.05) total aerobes, whereas supplementation with MHA-FA increased (P < 0.05) total aerobes and lactobacilli populations in proximal SI. Among the gnotobiotic pigs, 8 pigs (2 isolators) were monoassociated with a bacteria closely related to <i>Providencia</i> spp. and 16 pigs (4 isolators) were monoassociated with <i>Enterococcus faecium</i> (EF). Species of bacterial contaminant and diet composition did not affect residual MET or MHA-FA in digesta. Decreased (P < 0.05) apparent residual MET in digesta compared with MHA-FA in CON but not monoasscoiated pigs, along with significantly higher (P<0.05) MET associated radioactivity at 5% SI tissue suggested that microbial metabolism of MHA-FA increases its retention in small intestinal digesta and contributes in part to the lower bioefficacy of MHA-FA compared to MET. A comparison of CON and EF pigs showed that wheat/barley diets increased digesta viscosity (<i>P</i> < 0.01) and proliferating cell nuclear antigen (PCNA) expression (<i>P</i> < 0.001) and tended to decrease (<i>P</i> < 0.07) aminopeptidase N (APN) activity. Monoassociation decreased (<i>P</i> < 0.01) body weight, relative spleen weight, crypt depth, PCNA expression, caspase-3 activity, sucrase expression, total goblet cells in crypts and mucin gene expression and increased (<i>P</i> < 0.01) relative SI length, digesta viscosity, villus height, APN and sucrase activity. Interactive effects between cereal grain type and microbial status were observed only as trends (<i>P</i> < 0.1) for PCNA, Muc2, APN and sucrase suggesting these effects were mediated indirectly through microbial changes. Decreased % retained chromic oxide in digesta at all SI locations and no chromic oxide at 95% SI length in monoassociated pigs indicated slower small intestinal transit of digesta in monoassociated pigs. We successfully developed the chromic oxide microassay for estimating chromic oxide in 1/20th of original sample size (2.0 g). Results of this study indicate that microbial metabolism of MHA-FA contributes in part to the lower bioefficacy of MHA-FA compared to MET. Monoassociation had major effects on intestinal physiology whereas limited indirectly mediated effects of cereal type were observed suggesting no major influences of cereal grain type during the short early post-weaning phase.
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Avaliação de componentes da fibra como marcadores internos e de alcanos para estimar o fluxo de digesta no duodeno de bovinos / Evaluation of fiber components as internal markers and alkanes for duodenal digesta flow estimation in cattleMesquita, Francisco Rondon 01 March 2012 (has links)
The use of ADF as internal Marker of duodenal digesta flow was evaluated, for this
the intestinal degradability of fiber was studied. Four Holstein calves (156± 33 kg), fitted with
duodenal cannula T simple, and one calve fitted on the rumen, fed diet base with black oat
and supplement, was used. Seven feeds were weighted on the polyester bags (7x5,5cm;
25μm) and treated at different ruminal incubation times (12, 24, 36 and 48 hours). After the
respective incubations times, the bags were introduced in the duodenum of animals, recovered
on the faeces and analyzed. The means of fiber fraction obtained posruminally and on the
samples recovered on the faeces, were significantly different (P<0,05). The percent difference
was 6,44, 2,07 e 0,90% on DM basis, for NDF, ADF and ADL, respectively. The
disappearance of ADL indicated loss of particles through the pores of the bags, thereby the
means were corrected for the loss of ADL, improving the regression coefficients and intercept
of the regression equations, demonstrating the potential of using the ADF as an internal
marker of digesta flow in ruminants. Additionally, was evaluated the duodenal digesta flow
on cattle, with different markers. The means obtained from the ADF and ADL were similar,
2,025 and 2,135 kgDM/day, respectively. The n-alkanes presented low fecal recovery (C31=
63,3%; C32=46,7% e C33=75,6%), this may have contributed to the high variability of the
results obtained from the n-alkanes. The n-alkane C32 overestimated the duodenal flow of
DM, 3,855 kgDM/day. The ADF was useful for to measure the duodenal digesta flow, even
small loss was detected, this did not prejudice the assessment. The ADF was efficient for
measure digesta flow of DM, differently of the n-alkanes that overestimated (C32) and
presented high variability (C31, C32 and C33). / Este estudo foi conduzido com o objetivo de avaliar o potencial do uso de
componentes da fibra como marcadores internos e alcanos na estimativa do fluxo duodenal
em bovinos. Para tanto foi avaliada a degradabilidade intestinal das frações fibrosas de
diferentes alimentos. Foram utilizados quatro bovinos da raça holandesa dotados de cânula
tipo T simples no duodeno e um bovino dotado de fistula ruminal, com dieta a base de
Aveia Preta e concentrados (60:40). Foram conduzidos ensaios com sete diferentes alimentos,
estes sendo submetidos a diferentes tempos de incubação ruminal, (12, 24, 36 e 48 horas). Por
meio da técnica dos saquinhos móveis, foi avaliada a degradação intestinal dos alimentos. As
médias das frações fibrosas obtidas pós-ruminalmente e recuperadas nas fezes diferiram
significativamente de FDN, FDA e LDA (P<0,05). O desaparecimento em percentual da MS
foi de 6,44, 2,07 e 0,90%, para FDN, FDA e LDA, respectivamente. No entanto a análise de
regressão linear indicou altos coeficientes de determinação para todos os tempos de
incubação. O desaparecimento em proporção de FDA e LDA foram estatisticamente iguais
em todos os tempos de incubação (P>0,05), indicando perda de partículas pelos poros dos
saquinhos. A correção dos teores de FDA, pela perda de LDA não afetou os coeficientes de
determinação que permaneceram elevados. A estimativa do fluxo de duodenal de MS com a
FDA e a LDA foram similares, 2,025 e 2,135 kgMS/dia, respectivamente. Os n-alcanos
apresentaram baixa recuperação fecal (C31= 63,3%; C32=46,7% e C33=75,6%),o que pode
ter contribuído para alta variabilidade dos resultados. O C32 superestimou os valores de fluxo
duodenal de MS, sendo que fluxo médio obtido pelo C32, corrigido pela excreção fecal do
alcano, foi de 3,855 kgMS/dia, enquanto o observado com o FDA foi de 2,065kgMS/dia e
2,135 kgMS/dia com base no LDA. O FDA foi eficiente para medir o fluxo duodenal de MS, ,
diferentemente do n-alcano dosado, o C32, que superestimou este parâmetro e, como C31 e
C33, apresentou resultados com alta variabilidade.
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