低蛋白质饲粮中苏氨酸水平对离乳前期梅花鹿仔鹿生长性能和营养物质表观消化率的影响

Effects of Threonine Level in a Low Protein Diet on Growth Performance and Nutrient Apparent Digestibility of Early Weaning Sika Deer

本试验旨在研究低蛋白质饲粮中苏氨酸水平对离乳前期梅花鹿仔鹿生长性能和营养物质表观消化率的影响。选择24只健康无病的3月龄雄性梅花鹿,随机分为4组,每组6只。4组仔鹿限量饲喂4种不同的饲粮,各组饲粮赖氨酸、蛋氨酸水平均分别为0.87%、0.28%。其中,高蛋白质饲粮对照组(Ⅰ组)仔鹿饲喂蛋白质水平为16%的高蛋白质饲粮,低蛋白质饲粮试验组(Ⅱ~Ⅳ组)仔鹿饲喂蛋白质水平为14%并添加不同水平苏氨酸的低蛋白质饲粮,各组饲粮中苏氨酸水平分别为0.54%(Ⅰ组)、0.46%(Ⅱ组)、0.59%(Ⅲ组)、0.72%(Ⅳ组)。预试期为15 d,正试期为30 d。结果表明:1)高蛋白质饲粮对照组的平均日增重(ADG)极显著高于Ⅱ组(P<0.01),与Ⅲ、Ⅳ组差异不显著(P>0.05);高蛋白质饲粮对照组的料重比(F/G)极显著高于Ⅲ、Ⅳ组(P<0.01),极显著低于Ⅱ组(P<0.01)。2)高蛋白质饲粮对照组的粗蛋白质表观消化率极显著低于Ⅲ和Ⅳ组(P<0.01),极显著高于Ⅱ组(P<0.01);高蛋白质饲粮对照组能量表观消化率极显著低于Ⅲ、Ⅳ组(P<0.01),与Ⅱ组无显著差异(P>0.05);Ⅲ组钙表观消化率极显著高于Ⅱ组(P<0.01),与其他组差异不显著(P>0.05)。3)高蛋白质饲粮对照组的组氨酸、天冬氨酸、谷氨酸、甘氨酸、半胱氨酸表观消化率显著高于Ⅱ组(P<0.05),与Ⅱ组其他氨基酸表观消化率无显著差异(P>0.05);高蛋白质饲粮对照组赖氨酸、蛋氨酸、苏氨酸、精氨酸、丙氨酸、酪氨酸表观消化率极显著低于Ⅲ组(P<0.01),缬氨酸、亮氨酸、苯丙氨酸、丝氨酸表观消化率显著低于Ⅲ组(P<0.05);高蛋白质饲粮对照组除丙氨酸的表观消化率极显著低于Ⅳ组(P<0.01)以及赖氨酸、苏氨酸、缬氨酸、丙氨酸表观消化率显著低于Ⅳ组(P<0.05)外,其他氨基酸的表观消化率与Ⅳ组无显著差异(P>0.05)。由此得出,低蛋白质饲粮中适宜水平的苏氨酸对离乳前期梅花鹿仔鹿的生长性能和营养物质消化利用具有促进作用;当饲粮赖氨酸、蛋氨酸水平相同时,饲喂蛋白质水平为14%、苏氨酸水平为0.59%的低蛋白质饲粮的梅花鹿仔鹿的生长性能和营养物质表观消化率均优于饲喂蛋白质水平为16%的高蛋白质饲粮的梅花鹿仔鹿。

This experiment was conducted to investigate the effects of threonine （Thr） level in a low protein diet on growth performance and nutrient apparent digestibility of early weaning sika deer. Twenty-four healthy 3-month-old male sika deer were randomly divided into 4 groups with 6 deer per group. Infant deer restricted feeding 4 different diets and lysine （Lys） and methionine （Met） levels in all diets were 0.87% and 0.28%, respectively. Infant deer in high protein diet control group （group I ） were fed a high protein diet with 16% protein level, and infant deer in low protein diet test groups were fed a low protein diet with 14% protein level and different levels of Thr. The Thr level in 4 diets was 0.54% （ group I ）, 0.46% （ groupⅡ）, 0.59% （group Ⅲ ）, 0.72% （group IV ）. The pretrial period was 15 days, and the formal period was 30 days. The re- sults showed as follows ： 1 ） the average daily gain （ADG） of high protein diet control group was extremely significantly higher than that of group Ⅱ （ P〈0.01 ）, and had no significant difference compared with groups HI and IV （P〉0.05）. The feed/gain （F/G） of high protein diet control group was extremely significantly higher than that of groups III and IV （ P〈0.01 ）, which was extremely significantly lower than that of group lI （ P〈0.01 ）. 2） The apparent digestibility of crude protein of high protein diet control group was extremely sig- nificantly lower than that of groups Ill and IV （ P〈0.01 ）, which was extremely significantly higher than that of group lI （ P〈0.01 ）. The apparent digestibility of energy of high protein diet control group was extremely sig- nificantly lower than that of groups 11 and IV （P〈0.01）, which had no significant difference compared with group II （P〉0.05）. The apparent digestibility of calcium of group lI[ was significantly higher than that of group II （P〈0.01）, which had no significant difference compared with other groups （P〉0.05）. 3） The ap- parent digestibility of histidine （ His）, aspartic acid （ Asp）, glutamic acid （ Glu）, glycine （Gly） and cysteine （Cys） of high protein diet control group was significantly higher than that of group II （P〈0.05）, and the ap- parent digestibility of other amino acids in group lI had no significant difference （P〉0.05）. The apparent di- gestibility of Lys, Met, Thr, arginine （Arg）, alanine （Ala） and tyrosine （Tyr） of high protein diet control group was extremely significantly lower than that of group Ill （P〈0.01）, and the apparent digestibility of valine （Val）, leucine （Leu）, phenylalanine （Phe） and serine （Ser） was significantly lower than that of group Ill （P〈0.05）. The apparent digestibility of Ala of high protein diet control group was extremely signifi- cantly lower than that of group IV （ P〈0.01 ） and the apparent digestibility of Lys, Thr, Val and Ala was sig- nificantly lower than that of group IV （P〈0.05）, but it was no significant difference in the apparent digestibili- ty of other amino acids （ P〉0.05）. It can be seen that the appropriate threonine level in the low protein diet can promote the growth and nutrient digestion and utilization of early weaning sika deer. Under the same dietary Lys and Met levels, the growth performance and nutrient apparent digestibility of sika deer fed 0.59% Thr low protein diet with protein level of 14% are better than those fed high protein diet with protein level of 16%.