羔羊饲粮中添加镁对营养物质消化代谢的影响

Influence of magnesium supplement in lamb diets on digestion and metabolism of nutrients

选用5.5月龄无角陶赛特公羊与寒滩(小尾寒羊×滩羊)母羊的杂种公羔,研究饲粮中分别添加0(Ⅰ组)、0.075%(Ⅱ组)0、.150%(Ⅲ组))、0.255%(Ⅳ组)氧化镁,对营养物质消化代谢的影响.结果表明,羔羊日均食入镁量与粪镁排出量随镁添加水平增加而线性增高,Ⅱ组食入镁量显著高于Ⅰ组(P<0.10),Ⅳ组显著高于Ⅲ组(P<0.10);Ⅱ、Ⅲ组粪镁排出量显著高于Ⅰ组(P<0.10),Ⅳ组极显著高于Ⅰ、Ⅱ组(P<0.01);镁消化率和存留率随镁添加量提高而有所下降,Ⅲ、Ⅳ组的镁消化率显著低于Ⅰ组(P<0.10),Ⅳ组低于Ⅱ组(P<0.10).各饲粮间的干物质、有机物质、酸性洗涤纤维的食入量及消化率差异均不显著(P>0.10).Ⅱ、Ⅳ组氮表观消化率(ND)极显著高于Ⅰ组(P<0.01),Ⅲ组显著高于Ⅰ组(P<0.10);Ⅱ、Ⅲ组氮存留率(NR)显著高于Ⅰ组(P<0.10),Ⅳ组呈高于Ⅰ组的趋势(P=0.134).钙消化率随镁添加水平提高而下降(P>0.10),Ⅲ、Ⅳ组钙消化率呈低于Ⅰ组的趋势(P=0.217,P=0.113).磷消化率似与饲粮镁浓度无关,其中Ⅰ(P<0.10)、Ⅳ(P<0.10)、Ⅲ组(P=0.126)的磷消化率均高于Ⅱ组.

The influence of supplementing magnesium（MgO） at 0 %,0.075 %,0.150 % and 0.225 % in lamb diets on digestion and metabolism of nutrients was studied by using cross-bred male lambs Poll Dorset♂×（small tailed Han sheep×Tan）♀,at the age of five and a half months.The results showed that the intake of Mg（MgI） and Mg excreted in feces（MgF） increased linearly with the increasing of Mg levels in diets.MgI from groupⅡwas higher significantly than that of groupⅠ（P〈0.10）,and MgI from group Ⅳ was higher significantly than that of group Ⅲ（P〈0.10）.MgF from groupⅡand Ⅲ were significantly higher than that of groupⅠ（P〈0.10）,and MgF from group Ⅳ was significantly higher than that of groupⅠand Ⅱ（P〈0.01）.Digestibility and retention of Mg（MgD,MgR） were decreased linearly as the increasing of Mg level in diets.MgD from groups Ⅲ and Ⅳ were significantly lower than that from group Ⅰ（P〈0.10）,and MgD for group Ⅳ was significantly lower than that from group Ⅱ（P〈0.10）.There were no significant differences on DMI,OMI,ADFI,DMD,OMD,ADFD among all the diets（P〉0.10）.The apparent digestibility of nitrogen（ND）from groupⅡand Ⅳ were significantly higher than that of group Ⅰ（P〈0.01）,and ND from group Ⅲ was significantly higher than that of groupⅠ（P〈0.10）.Nitrogen retention（NR） of group Ⅱand Ⅲ was lower than those of groupⅠ（P〈0.10）.Calcium digestibility（CaD） decreased with the increasing of Mg levels in diets（P〉0.10）.CaD from group Ⅲ and Ⅳ trended to be lower than that of group Ⅰ（P=0.217,P=0.113）.Phosphorus digestibility（PD） seems to be not related to the levels of Mg in diets,but the PD from group Ⅰ（P〈0.10）,Ⅳ（P〈0.10）and Ⅲ（P=0.126）were higher than that of group Ⅱ.