不同越冬饲料对蜜蜂中肠消化酶活性、组织发育状态以及抗氧化酶基因表达的影响

本试验旨在研究不同越冬饲料对蜜蜂中肠消化酶活性、组织发育状态以及抗氧化酶基因表达的影响,以便为广大蜂农选择越冬饲料提供参考。在2015年10月底选取群势相当的本地意大利蜜蜂(Apis mellifera L.)越冬蜂群(群内无储备越冬饲料脾)9群(5框蜂/群),随机分为3个试验组(3群/组),从11月2号开始分别以蜂蜜(蜂蜜组)、果葡糖浆(果葡糖浆组)和白砂糖水(白砂糖∶水=2∶1,蔗糖组)为越冬饲料进行饲喂,饲喂至11月下旬蜂群进入越冬期。整个试验期为2015年10月底至2016年3月初。分别于越冬前(11月初)、越冬中期(1月初)和越冬后(3月初)采集蜜蜂中肠,测定中肠消化酶(淀粉酶、蔗糖酶和蛋白酶)活性,在越冬中期采集蜜蜂中肠用于中肠组织发育状态和抗氧化酶基因超氧化物歧化酶1(Sod1)、超氧化物歧化酶2(Sod2)和过氧化氢酶(CAT)]相对表达量等指标的检测。结果表明:在越冬中期,果葡糖浆组和蜂蜜组的蜜蜂中肠内淀粉酶活性显著高于蔗糖组(P0.05)。在越冬中期和越冬后,饲喂不同越冬饲料的蜜蜂中肠内蔗糖酶活性差异不显著(P0.05)。在越冬中期,果葡糖浆组的蜜蜂中肠内蛋白酶活性显著高于蔗糖组和蜂蜜组(P0.05)。蜂蜜组和蔗糖组的蜜蜂中肠肠壁厚度极显著大于果葡糖浆组(P0.01),且蜂蜜组和蔗糖组的蜜蜂中肠隐窝深度也极显著大于果葡糖浆组(P0.01)。在越冬中期,蔗糖组的蜜蜂中肠Sod1基因的相对表达量显著高于蜂蜜组和果葡糖浆组(P0.05)。由此得出,蜂蜜能够提高越冬蜂中肠消化酶活性,蜂蜜和白砂糖有利于越冬蜂中肠组织的发育,而且白砂糖能够提高越冬蜂中肠抗氧化酶基因的表达。因此,蜂蜜和白砂糖比果葡糖浆更适合作为蜜蜂的越冬饲料。

Effects of Different Overwintering Feeds on Midgut Digestive Enzyme Activities,Tissue Development Status and Antioxidant Enzyme Gene Expression of Honeybees

The experiment was conducted to study the effects of different overwintering feeds on midgut diges-tive enzyme activities, tissue development status and antioxidant enzyme gene expression of honeybees, in or-der to provide reference for the beekeepers choose winter feed overwintering feeds. At the end of October 2015, nine overwintering colonies ( without overwintering feed reserve) of local Italian honeybees ( Apis mel-lifera L.) with equal colony population were randomly divided into 3 experimental groups ( 3 colonies per group) , and were fed honey ( honey group) , fructose corn syrup ( fructose corn syrup group) and white sugar water (white sugar :water=2:1, sucrose group) as overwintering feed from November 2 to late November when bee colonies entered into overwintering period, respectively. The experiment lasted from the end of Octo-ber 2015 to early March 2016. In order to determine the midgut digestive enzyme ( amylase, sucrase and prote-ase) activities, midgut samples were collected in early November ( before overwintering) , early January ( the middle period of overwintering) and early March ( after overwintering) , respectively. And, in early January, midgut samples were collected to determine the midgut tissue development status and the relative expression lev-els of antioxidant enzyme genes, such as superoxide dismutase 1 ( Sod1) , superoxide dismutase 2 ( Sod2) and catalase ( CAT) genes. The results showed as follows:the midgut amylase activity of fructose corn syrup group and honey group was significantly higher than that of sucrose group in early January ( P<0.05) . Different over-wintering feeds did not significantly affect the midgut sucrase activity in early January and early March ( P>0.05) . The midgut protease activity of fructose corn syrup group was significantly higher than that of sucrose group and honey group in early January (P<0.05). The midgut wall thickness of sucrose group and honey group was significantly higher than that of fructose corn syrup group ( P<0.01) , and the midgut crypt deepness of sucrose group and honey group was also significantly higher than that of fructose corn syrup group ( P<0.01) . The relative expression level of Sod1 gene from midgut of sucrose group was significantly higher than that of fructose corn syrup group and honey group in early January ( P<0.05) . In conclusion, honey can im-prove midgut digestive enzyme activities of overwintering honeybees, honey and white sugar are beneficial to the development of midgut tissue of overwintering honeybees, and white sugar can improve the midgut antioxi-dant gene expression of overwintering honeybee. Therefore, honey and white sugar as the overwintering feed for honeybee are better than fructose corn syrup.