影响麋鹿茸分枝和角重量的年龄因素分析

Analysis of age factors affecting the branching velvet and weight of antlers in Père David’s deer(Elaphurus davidianus)

角是反刍动物有别于其他动物的明显特征(Wang et al.,2019)。与牛科动物、羊科动物的洞角不同,鹿角为实心骨质、可年度周期性脱落、其分枝和重量受到众多因素的影响,是鹿类保护、养殖、育种领域关注的焦点问题(Bowyer,1991)。幼鹿每增长1岁,角增加1个分枝;角直径和重量也随之增加(夏志强等,2023);同一年龄组同一个体的不同阶段,茸生长速度和重量增加也不相同(Hassanin et al.,2012;李春义,2017;夏志强等,2023);鹿茸软骨与机体其他软骨组织不同,内有血管(鲍加荣等,2008;Chen et al.,2019),可供给茸生长所需的营养(Clements et al.,2010;Lin et al.,2019);血管内皮生长因子(Vascular endotheli‐al growth factor,VEGF)的含量变化对鹿茸的生长速度、茸直径、分枝数、分枝方向及角重和形态发育有重要影响(Clark et al.,2006)。

Père David’s deer(Elaphurus davidianus)is originally deer species native distributed in the plains and wetlands of China.Characterized by cylindrical antlers with a main branch in front and auxiliary branches behind,they shed their antlers after the winter solstice.In Père David’s deer,the relationship between external parameters and the weight of the antlers varies significantly for Père David’s deer.In this study,we conducted a comprehensive analysis by tracking and recording the dates of antler branching,the number of branches,and the weight of antlers from 2019 to 2023.Additionally,we utilized an infrared rangefinder to measure the length,diameter,and total length of antler branches across different age groups.In 2022,we further measured the parameters of shed antlers’cross-sections using a caliper and employed qRT-PCR to determine changes in the content of related molecules in the velvet tissue of different age groups.Subsequently,we conducted a correlation analysis of antler branching and weight parameters with age.The results showed that with each additional year of age,the antlers exhibited an increase of one branch.Between the ages of 3 and 7,the weight of antlers demonstrated the following progression:1223 g,872 g,884 g,899 g,and 699 g,respectively.Furthermore,for every additional centimeter of antler stem diameter,the weight of antler increases of 535 g,531 g,613 g,681 g,and 721 g,respectively.The content of vascular endothelial growth factor(VEGF)also exhibited an age-related increase(P=0.0007,n=18).Under consistent age conditions,the escalation in antler weight displayed the strongest correlation with the number of antler branches(r=0.8274,P=0.0054),antler diameter(r=0.8364,P=0.0007),and antler total length(r=0.7971,P=0.0073).Moreover,the weight of the antler cross-section positively correlated with outer diameter length(r=0.9470,P=0.0066),outer diameter width(r=0.9246,P=0.0018),and outer diameter length-width ratio(r=0.9217,P=0.0027).The rise in velvet weight exhibited positive correlations with the daily growth length,dry total length,and main stem circumference of velvet.However,from 20 to 60 days post-regeneration,the content of VEGF demonstrated a subsequent decrease accordingly.Nonetheless,these findings offer valuable insights into understanding the relationship between the number of antler branches and vascular endothelial regeneration factors,as well as screening molecular mechanisms associated with deer velvet production.Furthermore,they serve as a foundation for enhancing deer velvet production,breeding practices,and the scientific conservation of deer species.