<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>1405-3195</journal-id>
<journal-title><![CDATA[Agrociencia]]></journal-title>
<abbrev-journal-title><![CDATA[Agrociencia]]></abbrev-journal-title>
<issn>1405-3195</issn>
<publisher>
<publisher-name><![CDATA[Colegio de Postgraduados]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S1405-31952007000600597</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Concentración de urea en plasma y respuesta productiva de cerdos en iniciación alimentados con dietas sorgo-pasta de soya bajas en proteína]]></article-title>
<article-title xml:lang="en"><![CDATA[Plasma urea concentration and growth performance of nursery pigs fed sorghum-soybean meal, low-protein diets]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Trujillo-Coutiño]]></surname>
<given-names><![CDATA[Josué E.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Figueroa-Velasco]]></surname>
<given-names><![CDATA[José L.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Martínez-Aispuro]]></surname>
<given-names><![CDATA[Manuel]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Zamora-Zamora]]></surname>
<given-names><![CDATA[Vicente]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Cordero-Mora]]></surname>
<given-names><![CDATA[José L.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Sánchez-Torres]]></surname>
<given-names><![CDATA[Ma. Teresa]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Cuca-García]]></surname>
<given-names><![CDATA[Manuel]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Cervantes-Ramírez]]></surname>
<given-names><![CDATA[Miguel]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Colegio de Postgraduados Campus Montecillo ]]></institution>
<addr-line><![CDATA[Montecillo Estado de México]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Universidad Autónoma de Baja California Instituto de Ciencias Agrícolas ]]></institution>
<addr-line><![CDATA[Mexicali Baja California]]></addr-line>
<country>Mexico</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>09</month>
<year>2007</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>09</month>
<year>2007</year>
</pub-date>
<volume>41</volume>
<numero>6</numero>
<fpage>597</fpage>
<lpage>607</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S1405-31952007000600597&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S1405-31952007000600597&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S1405-31952007000600597&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen: Existe poca información acerca del uso de dietas con baja proteína cruda (PC) para cerdos en iniciación. Por tanto, se realizaron dos experimentos para determinar el porcentaje mínimo de PC en dietas sorgo-pasta de soya que no afecte el comportamiento productivo, utilizando urea en plasma como indicador. En el experimento 1, los tratamientos (% PC) fueron: T1) testigo 20.5; T2) 19.0; T3) 17.5; T4) 16.0; T5) 14.5, y se aplicaron a 10 cerditas en iniciación usando un diseño cruzado con periodos de 7 d. El último día de cada periodo se obtuvo una muestra de sangre de la vena cava para determinar urea. La menor concentración de este metabolito indicó que la PC en la dieta puede reducirse hasta 16%. Mediante regresión no lineal exponencial se determinó que la PC en la dieta se puede reducir hasta 14.86% y aumentar hasta 20.12% para obtener la mínima y máxima concentración de urea en plasma. En el experimento 2, los tratamientos (%PC y Mcal EM kg-1) fueron: T1) dieta estándar, 20.5 y 3.265; T2) 20.5 y 3.165; T3) 16 y 3.265; T4) 16 y 3.165; T5) 14.5 y 3.265; T6) 14.5 y 3.165, para 24 machos castrados usando un diseño en bloques completos al azar. El menor nivel de proteína redujo la urea en plasma, mientras que al reducir la energía disminuyó la grasa dorsal y aumentó la conversión alimenticia. Lo anterior indica que la urea se reduce al disminuir la PC en la dieta; que la grasa dorsal es menor al bajar la energía; y que otros factores como el peso inicial también influyen en la respuesta de los cerdos en iniciación.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract: There is little information on the use of low crude protein (CP) diets for nursery pigs. Therefore, two experiments were conducted to determine the minimum percentage of CP in sorghum-soybean meal diets that would not affect growth performance, using plasma urea as a marker. In experiment 1, the treatments (%CP) were: T1) control 20.5; T2) 19.0; T3) 17.5; T4) 16.0; T5 14.5, applied to 10 nursery female pigs using a cross over design with periods of 7 d. The last day of each period, a blood sample was obtained from the cava vein to determine urea. The lowest concentration of this metabolite indicated that the CP in the diet can be reduced by as much as 16%. Using exponential non-linear regression, it was determined that the CP in the diet can be reduced by as much as 14.86% and increased by as much as 20.12% to obtain the minimum and maximum plasma urea concentration. In experiment 2, the treatments (%CP and Mcal EM kg-1) were as follows: T1) standard diet, 20.5 and 3.265; T2) 20.5 and 3.165; T3) 16 and 3.265; T4) 16 and 3.165; T5) 14.5 and 3.265; T6) 14.5 and 3.165, for 24 barrows using a randomized complete blocks design. The lowest protein level reduced plasma urea, while backfat was reduced with a reduction in energy and food conversion increased. The above indicates that the urea is reduced when CP is reduced in the diet; that backfat is lower when energy is decreased; and that other factors such as initial weight also influence the performance of nursery pigs.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Cerdos iniciación]]></kwd>
<kwd lng="es"><![CDATA[dietas con baja proteína]]></kwd>
<kwd lng="es"><![CDATA[respuesta productiva]]></kwd>
<kwd lng="es"><![CDATA[urea en plasma]]></kwd>
<kwd lng="en"><![CDATA[Nursery pigs]]></kwd>
<kwd lng="en"><![CDATA[low protein diets]]></kwd>
<kwd lng="en"><![CDATA[growth performance]]></kwd>
<kwd lng="en"><![CDATA[plasma urea]]></kwd>
</kwd-group>
</article-meta>
</front><back>
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<given-names><![CDATA[W.]]></given-names>
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<article-title xml:lang=""><![CDATA[Effect of dietary energy concentration and apparent ileal digestible lysine:metabolizable energy ratio on nitrogen balance and growth performance of young pigs]]></article-title>
<source><![CDATA[J. Anim. Sci.]]></source>
<year>2003</year>
<volume>81</volume>
<page-range>1227-36</page-range></nlm-citation>
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