不同断奶日龄羔羊瘤胃组织显微及超微结构比较

Comparative Study on Ruminal Histo-ultra Microstructure of Lambs Weaned at Different Time

试验通过比较不同断奶日龄的湖羊羔羊瘤胃组织结构的差异,特别是瘤胃乳头超微结构变化,旨在为羔羊适宜断奶日龄的确定提供瘤胃生长发育的依据。选择新生湖羊羔羊24只(初生重:2.80 kg±0.08 kg),随机分为3组,每组8只,分别为30日龄早期断奶组(EEW-30)、45日龄早期断奶组(EW-45)和60日龄常规断奶组(NW-60)。在各断奶日龄及75日龄时每组分别屠宰4只羔羊,测定体重及瘤胃空重,计算瘤胃相对重量;采集瘤胃组织进行显微及超微形态学测定。结果显示:①EEW-30组羔羊断奶体重极显著低于NW-60组(P<0.01),而EW-45组与NW-60组断奶体重无显著差异(P>0.05);75日龄时3组羔羊的体重无显著差异(P>0.05)。各组羔羊瘤胃相对重量与其体重变化规律相同。②光镜下可见:断奶时,EEW-30组瘤胃壁厚度极显著低于NW-60组(P<0.01),EW-45组与NW-60组无显著差异(P>0.05);75日龄时,EW-45组羔羊瘤胃壁厚度显著高于NW-60组(P<0.05)。断奶时EEW-30组瘤胃乳头较短小,极显著短于NW-60组(P<0.01),EW-45组也显著短于NW-60组(P<0.05)。断奶时瘤胃乳头宽度和面积在3组间差异均不显著,在75日龄时也无显著组间差异(P>0.05)。③扫描电镜观测结果显示:EEW-30组断奶时单位面积瘤胃微乳头(ruminal micro-papillae)数量极显著低于NW-60组(P<0.01),而EW-45与NW-60组间无显著差异(P>0.05);75日龄时,3组羔羊单位面积瘤胃微乳头数量无显著差异(P>0.05)。上述试验结果显示,断奶时羔羊瘤胃形态结构在EEW-30与NW-60组间差异明显,而EW-45与NW-60组较为接近,瘤胃微乳头状结构也呈相同变化趋势。提示45日龄时断奶较为适宜。

The purpose of the experiment was to compare the differences of rumen tissue structure,especially the changes of ultrastructure of ruminal papillae in Hu lambs at different weaning age,so as to provide the basis for determining the suitable weaning age of Hu lambs.Twenty-four newborns of Hu sheep with birth weight of 2.80 kg±0.08 kg were randomly divided into three groups,8 lambs in each group,weaning at 30 days old(EEW-30),45 days old(EW-45)and 60 days old(NW-60),respectively.Four lambs in each group were slaughtered at corresponding weaning time and at the age of 75 days,respectively.The body weight and rumen weight were measured,and the ruminal relative weight was calculated.The rumen was sampled for morphological measurement.The results showed that:①The body weight of lambs at weaning time in EEW-30 group was extremely lower than that in NW-60 group(P<0.01),but there was no significant difference between EW-45 and NW-60 groups(P>0.05),and neither was any significant difference of the body weight among 3 groups at 75 days old(P>0.05).The change of the ruminal relative weight in 3 groups was in accord with that of the body weight.②Under the light microscope,the tunica mucosa thickness of rumen in EEW-30 group was significantly lower than NW-60 group(P<0.01),and there was no significant difference between EW-45 group and NW-60 group(P>0.05)at weaning age.At 75 days,the tunica mucosa thickness of rumen in EW-45 group was significantly higher than that in NW-60 group(P<0.05).At weaning age,the rumen papillae of EEW-30 group was extremely significant shorter than that in NW-60 group(P<0.01),and EW-45 group was also significantly shorter than NW-60 group(P<0.05).However,there was no significant difference in the width and area of rumen papilla at different weaning time and at day 75(P>0.05).③Under scanning electronic microscope,the number of ruminal micro papillae structure perμm2 at weaning age in EEW-30 group was extremely significantly lower than that in NW-60 group(P<0.01),but there was no significant difference between EW-45 group and NW-60 group(P>0.05).At the age of 75 days,there was no significant difference in the number of ruminal micro-papillae structure perμm2 among the three groups(P>0.05).The results showed that there was significant differences in ruminal morphology between EEW-30 and NW-60 groups at weaning age,while EW-45 and NW-60 groups were more similar,and the change trend of ultra-microstructure of ruminal micro-papillae was the same.It was suggested that weaning at 45 days of age was more appropriate.