<p style="text-align: justify;"><span id="result_box" lang="fr"><strong><span class="hps alt-edited">Digestion des</span> <span class="hps atn">hydrates de carbone (</span>sucres, l'amidon, la cellulose et <span class="hps">autres fibres</span>)</strong> <span class="hps">-</span> Les sucres s<span class="hps">olubles</span> <span class="hps"></span><span class="hps">sont décomposés et</span> <span class="hps">absorbés</span> <span class="hps">dans l'intestin grêle</span><span>.</span> <span class="hps">Les monosaccharides</span> <span class="hps">tels que le glucose</span> <span class="hps">et le fructose</span> <span class="hps">sont</span> <span class="hps">absorbés</span> <span class="hps">directement</span> <span class="hps">par</span> les <span class="hps">cellules intestinales.</span> Les <span class="hps">disaccharides</span> <span class="hps">et l'amidon</span> <span class="hps">seront</span> <span class="hps">hydrolysés par</span> <span class="hps alt-edited">des</span> <span class="hps">enzymes dans</span> <span class="hps">l'intestin grêle</span> <span class="hps atn">(</span><span>amylase et</span> <span class="hps">diverses</span> <span class="hps">disaccharidases</span><span>)</span> <span class="hps alt-edited">avant absorption</span>. <span class="hps">L'intestin grêle</span> <span class="hps">a une grande</span> <span class="hps">capacité d'absorption des</span> <span class="hps">sucres simples et</span> de <span class="hps">l'amidon.</span> <span class="hps alt-edited">La coupure</span> <span class="hps">des glucides alimentaires</span> <span class="hps">communs</span> <span class="hps">conduit à</span> <span class="hps alt-edited">des monosaccharides</span> <span class="hps">qui peuvent être absorbés</span> <span class="hps">(glucose,</span> <span class="hps">fructose et galactose</span><span>) selon</span> <span class="hps">le schéma général suivant </span><span>:</span></span></p>
<p><br />Sucre (S<span id="result_box" lang="fr"><span class="hps alt-edited">accharose</span></span>) -&gt; glucose + fructose<br />Sucre du lait (Lactose) -&gt; glucose + galactose<br />Maltose -&gt; glucose<br />Amidon -&gt; maltose -&gt; glucose</p>
<p>&nbsp;</p>
<p style="text-align: justify;"><span id="result_box" lang="fr"><span class="hps">Les jeunes</span> <span class="hps">poulains</span> <span class="hps">ne peuvent pas digérer le</span> <span class="hps alt-edited">saccharose</span> <span class="hps">en grandes quantités</span> <span class="hps">jusqu'à</span> <span class="hps">environ 7</span> <span class="hps">mois d'âge</span><span>.</span> <span class="hps">Le lactose,</span> <span class="hps">qui est le</span> <span class="hps">sucre</span> <span class="hps">naturel</span> <span class="hps">du lait,</span> <span class="hps">est bien</span> <span class="hps">digéré</span> <span class="hps">jusqu'au sevrage</span><span>, puis</span> <span class="hps">la</span> <span class="hps">production</span> <span class="hps">de l'enzyme</span> <span class="hps">lactase</span> <span class="hps">qui est requise pour</span> <span class="hps">le</span> <span class="hps alt-edited">découpage du</span> <span class="hps">lactose</span> <span class="hps">est progressivement réduite</span><span>.</span> <span class="hps">A 2</span> <span class="hps">ans</span> <span class="hps">l'activité</span> <span class="hps">est si faible</span> <span class="hps">que de grandes</span> <span class="hps">quantités de lait</span> <span class="hps">ne doivent pas</span> <span class="hps alt-edited">être amenées</span>. <span class="hps">De petites quantités</span> <span class="hps">de lactose</span> <span class="hps">peuvent néanmoins être</span> <span class="hps">amenés à</span> d<span class="hps">es chevaux adultes</span>. <span class="hps">Il passera</span> <span class="hps">inchangé</span> <span class="hps alt-edited">au </span><span class="alt-edited">gros intestin</span>, <span class="hps">où il</span> <span class="hps">sera une source</span> <span class="hps">d'énergie pour les</span> <span class="hps">microbes</span><span>.</span> <span class="hps">Des quantités plus importantes</span> <span class="hps alt-edited">bouleverseront</span> <span id="result_box" lang="fr"> <span class="hps alt-edited">invariablement</span> </span><span class="hps">la digestion et</span> <span class="hps alt-edited">pourraient</span> <span class="hps">entraîner des diarrhées</span>.</span></p>
<p>&nbsp;</p>
<p style="text-align: justify;"><span id="result_box" lang="fr"><span class="hps">Une grande partie</span> <span class="hps">de l'amidon</span> <span class="hps">sera décomposée</span> <span class="hps">en glucose</span> <span class="hps">par les enzymes</span> <span class="hps">dans l'intestin grêle</span> <span class="hps">et absorbé</span><span>.</span> Des v<span class="hps">ariations</span> <span class="hps">existent</span> <span class="hps">cependant,</span> <span class="hps">selon le type</span> <span class="hps">d'amidon</span> <span class="hps alt-edited">et les quantités</span> <span class="hps alt-edited">distribuées</span> <span class="hps">par repas</span><span>.</span> <span class="hps">Plus de 95%</span> <span class="hps">de l'amidon de</span> <span class="hps atn">l'avoine et de l'</span><span>orge</span> <span class="hps">est absorbé</span> <span class="hps">dans l'intestin grêle</span> <span class="hps">et</span> <span class="hps">environ</span> <span class="hps">80</span><span>% de l'amidon</span> <span class="hps">de</span> <span class="hps">maïs</span><span>.</span> La f<span class="hps alt-edited">écule de pommes de terre</span> <span class="hps">est beaucoup moins</span> <span class="hps">digeste et</span> <span class="hps">sera transportée</span> <span class="hps">en quantités importantes</span> <span class="hps atn alt-edited">au </span><span class="alt-edited">gros intestin</span> <span class="hps">où elle y sera</span><span class="hps"> fermentée</span><span>.</span> <span class="hps alt-edited">Lorsque</span> <span class="hps alt-edited">de gros repas</span> <span class="hps">de concentrés</span> <span class="hps alt-edited">sont amenés</span>, <span class="hps">d'importantes quantités</span> <span class="hps">d'amidon</span> <span class="hps alt-edited">atteignent le </span><span class="alt-edited">gros intestin</span> <span class="hps">et</span> <span class="hps">subissent une fermentation</span>. <span class="hps atn">L'</span><span>énergie est absorbée</span> <span class="hps">sous forme d'acides</span> <span class="hps">gras</span> <span class="hps">à chaîne courte</span><span>, mais seulement après</span> <span class="hps">qu'une partie substantielle de</span> <span class="hps alt-edited">l'énergie soit</span> <span class="hps">perdue sous forme de</span> <span class="hps">gaz</span> <span class="hps">et</span> <span class="hps">comme nourriture des</span> <span class="hps">micro-organismes</span>.</span></p>
<p style="text-align: justify;">&nbsp;</p>
<p style="text-align: justify;"><span id="result_box" lang="fr"><span class="hps">Le cheval</span> <span class="hps">ne produit pas</span> <span class="hps">les enzymes qui</span> <span class="hps">peuvent briser</span> les composés <span class="hps">complexes,</span> <span class="hps">appelées</span> <span class="hps">glucides</span> <span class="hps">végétaux</span> <span class="hps">structurels telles que</span> <span class="hps">la cellulose,</span> <span class="hps">l'hémicellulose</span><span>,</span> <span class="hps">pectines</span> <span class="hps">et</span> <span class="hps">pentosanes</span>. <span class="hps">Ces composés</span> <span class="hps">passent à travers</span> <span class="hps">l'intestin grêle,</span> <span class="hps">et</span> <span class="hps">seront d'abord</span> <span class="hps">digérés</span> <span class="hps">par les microbes</span> <span class="hps">dans le</span> <span class="hps alt-edited">gros intestin</span><span>.</span> <span class="hps">Les</span> <span class="hps">produits finaux de</span> <span class="hps">cette</span> <span class="hps">fermentation</span> <span class="hps">sont les acides</span> <span class="hps">gras à chaîne courte</span><span>:</span></span></p>
<p style="text-align: justify;">Acide acétique (C2) Acide propionique (C3), Acide lactique (C3, généralement formé en plus petites quantités) Acide butyrique (C4).<br /><br /><span id="result_box" lang="fr"><span class="hps"></span></span></p>
<p style="text-align: justify;"><span id="result_box" lang="fr"><span class="hps">Lorsque</span> <span class="hps">le régime alimentaire</span> <span class="hps">contient peu ou pas</span> <span class="hps alt-edited">concentrés</span><span>, l'acide</span> <span class="hps">acétique</span> <span class="hps">représentera</span> <span class="hps">une grande partie de</span> <span class="hps">l'énergie</span> <span class="hps">qui est absorbée</span> <span class="hps alt-edited">depuis l'intestin</span><span>.</span> <span class="hps">L'acide butyrique</span> <span class="hps">sera également utilisé</span> <span class="hps">dans le métabolisme énergétique</span> <span class="hps">et</span> <span class="hps alt-edited">pour produire</span> <span class="hps">des graisses</span> <span class="hps">tissulaires.</span> <span class="hps">En plus de ces</span> <span class="hps">utilisations</span><span>, l'acide propionique</span> <span class="hps">est métabolisée</span> <span class="hps">en glucose et</span> <span class="hps">fournit</span> <span class="hps alt-edited">une composante importante du</span> <span class="hps alt-edited">glucose sanguin</span> <span class="hps">des chevaux.</span></span></p>
<p style="text-align: justify;">&nbsp;</p>
<p style="text-align: justify;"><span id="result_box" lang="fr"><span class="hps"></span></span><span id="result_box" lang="fr"><span class="hps">Les concentrations des</span> <span class="hps">acides gras</span> <span class="hps alt-edited">à courte chaîne</span> <span class="hps">varient selon</span> <span class="hps">les</span> <span class="hps">types</span> <span class="hps">d'alimentation et</span> <span class="hps">le</span> <span class="hps">temps</span> <span class="hps">après le repas.</span> <span class="hps alt-edited">Le ratio entre</span> <span class="hps">la concentration de</span> <span class="hps">ces acides dans</span> <span class="hps">le caecum</span> <span class="hps">varie</span> <span class="hps">d'une manière</span> <span class="hps">telle que</span> <span class="hps">les régimes riches en</span> <span class="hps">fourrages </span><span class="hps">donneront une</span> <span class="hps">forte concentration</span> <span class="hps">d'acétate</span> <span class="hps">par rapport au</span> <span class="hps">propionate</span><span>, tandis que</span> <span class="hps">les régimes riches en</span> <span class="hps">céréales</span> <span class="hps">favoriseront la production</span> <span class="hps">de propionate</span> <span class="hps">sur</span> l'<span class="hps">acétate.</span> <span class="hps">Dans le côlon</span> <span class="hps">le rapport entre les</span> <span class="hps">acides</span> <span class="hps">est</span> <span class="hps">moins</span> <span class="hps">influencé par le type</span> <span class="hps">d'aliments</span> <span class="hps">donné.</span></span></p>
<p style="text-align: justify;">&nbsp;</p>
<p style="text-align: justify;"><span id="result_box" lang="fr"><span class="hps">Les acides</span> <span class="hps">qui sont produits</span> <span class="hps alt-edited">abaissent le pH</span> <span class="hps alt-edited">du contenu du</span> <span class="alt-edited">gros intestin</span>. <span class="hps">Un</span> <span class="hps">pH dans</span> <span class="hps">une plage comprise entre</span> <span class="hps">6,6 et 7,5</span> <span class="hps">est maintenu par</span> <span class="hps">les</span> <span class="hps">nombreuses glandes</span> <span class="hps">de</span> <span class="hps alt-edited">toutes les parois</span> <span class="hps alt-edited">du gros intestin</span> <span class="hps">qui sécrètent</span> <span class="hps alt-edited">un</span> <span class="hps alt-edited">liquide <span id="result_box" lang="fr"><span class="hps alt-edited">riche </span>en</span></span> <span class="hps">bicarbonate <span id="result_box" lang="fr"><span class="hps atn">(</span><span class="alt-edited">alcalin</span>)</span>.</span> <span class="hps">Un régime</span> <span class="hps">avec peu de</span> <span class="hps">fourrage</span> <span class="hps">et</span> <span class="hps">une grande proportion de</span> <span class="hps">concentrés</span> <span class="hps">peut</span> <span class="hps">fermenter</span> <span class="hps">trop rapidement</span> <span class="hps alt-edited">produisant de l'acide</span> <span class="hps">lactique et</span> <span class="hps alt-edited">provoquant une descente</span> <span class="hps alt-edited">du pH dans</span> <span class="hps alt-edited">le </span><span class="alt-edited">gros intestin</span> <span class="hps alt-edited">en dessous de</span> <span class="hps">la normale</span> <span class="hps alt-edited">(l'acide lactique</span> <span class="hps">est plus acide que</span> <span class="hps">le propionate</span><span>,</span> l'<span class="hps">acétate et le</span> <span class="hps">butyrate</span><span>)</span><span>.</span> <span class="hps">Un</span> <span class="hps">faible pH</span> <span class="hps">dans le</span> <span class="hps alt-edited">gros intestin</span> <span class="hps">peut être préjudiciable</span> <span class="hps">aux microbes</span> <span class="hps">digérant les fibres</span> <span class="hps">qui sont</span> <span class="hps">moins tolérants</span> <span class="hps">à un pH</span> <span class="hps">plus bas que</span> <span class="hps">les</span> <span class="hps">espèces</span> <span id="result_box" lang="fr"><span class="hps alt-edited">digérant</span></span> <span class="hps alt-edited">l'amidon</span><span>.</span> <span class="hps">Dans de telles situations</span><span>, la formation</span> <span class="hps alt-edited">de gaz est augmentée</span><span>, provoquant une accumulation</span> <span class="hps">de gaz</span> <span class="hps">et éventuellement</span> des <span class="hps">coliques.</span></span><br /><br /><span id="result_box" lang="fr"><span class="hps"></span></span></p>
<p style="text-align: justify;"><span id="result_box" lang="fr"><span class="hps">Les régimes</span> <span class="hps">contenant</span> <span class="hps">des</span> <span class="hps">fourrages de</span> mauvaise <span class="hps">qualité avec une</span> <span class="hps">faible teneur en azote</span> <span class="hps">peuvent</span> <span class="hps">affamer les</span> <span class="hps alt-edited">microorganismes</span> <span class="hps">à un point tel</span> <span class="hps">que cela peut entrainer une faible</span> <span class="hps">efficacité de la digestion</span>. Les r<span class="hps">ations</span> <span class="hps">mixtes avec</span> <span class="hps">quelques</span> <span class="hps">matières amylacées</span> <span class="hps">bénéficient donc</span> <span class="hps">également</span> <span class="hps alt-edited">à la digestion des fibres</span> <span class="hps">en fournissant une source</span> <span class="hps">d'énergie facilement</span> <span class="hps">disponible pour</span> <span class="hps">les</span> <span class="hps alt-edited">microorganismes</span>.</span></p>
<p style="text-align: justify;"><span id="result_box" lang="fr"><span class="hps alt-edited">Ratio entre</span> <span class="hps">les acides</span> <span class="hps alt-edited">gras à courte chaîne</span> <span class="hps">dans</span> <span class="hps">le caecum</span> <span class="hps">et le colon</span> <span class="hps">d'animaux</span> <span class="hps alt-edited">recevant une ration</span> <span class="hps alt-edited">avec des ratios différents de fourrages et concentrés</span> <span>:</span></span></p>
<p style="text-align: justify;">&nbsp;</p>
<table style="width: 599px; height: 238px;" border="1">
<tbody style="text-align: left;">
<tr style="text-align: left;">
<td style="text-align: center;">Foin: Concentrés</td>
<td style="text-align: center;">Acétique%</td>
<td style="text-align: center;">Propionique%</td>
<td style="text-align: center;">Butyrique%</td>
</tr>
<tr style="text-align: center;">
<td style="text-align: left;" colspan="4">Caecum</td>
</tr>
<tr style="text-align: left;">
<td style="text-align: center;">1:0</td>
<td style="text-align: center;">76.2</td>
<td style="text-align: center;">14.8</td>
<td style="text-align: center;">8.0</td>
</tr>
<tr style="text-align: left;">
<td style="text-align: center;">3:2</td>
<td style="text-align: center;">70.4</td>
<td style="text-align: center;">21.2</td>
<td style="text-align: center;">7.2</td>
</tr>
<tr style="text-align: left;">
<td style="text-align: center;">1:4</td>
<td style="text-align: center;">61.2</td>
<td style="text-align: center;">26.0</td>
<td style="text-align: center;">10.2</td>
</tr>
<tr style="text-align: center;">
<td style="text-align: left;" colspan="4">Côlon</td>
</tr>
<tr style="text-align: left;">
<td style="text-align: center;">1:0</td>
<td style="text-align: center;">69.5</td>
<td style="text-align: center;">16.2</td>
<td style="text-align: center;">7.6</td>
</tr>
<tr style="text-align: left;">
<td style="text-align: center;">3:2</td>
<td style="text-align: center;">68.2</td>
<td style="text-align: center;">15.0</td>
<td style="text-align: center;">8.8</td>
</tr>
<tr style="text-align: left;">
<td style="text-align: center;">1:4</td>
<td style="text-align: center;">67.0</td>
<td style="text-align: center;">17.0</td>
<td style="text-align: center;">9.0</td>
</tr>
</tbody>
</table>