| Lipid plays an important role in honeybee’s growth and development. The currentresearch on the nutrient requirement of honeybees is relatively weak, and the addition level offatty acid in substitute pollen is not clear. This experiment was conducted to study the effectsof honeybee’s growth and development, lipid content in hemolymph and tissue, adulthoneybee’s longevity, related enzyme activity and gene expression by adding differentα-linolenic acid (ALA) levels in substitute pollen. The objective of this study was to exploreoptimal α-linolenic level of fatty acid in substitute pollen, and provide a theoretical basis andreference for lipids need, formulating feeding standards and compound honeybee substitutepollen. Study was divided into spring multiplication and autumn multiplication, and theresults as follows:Thirty-six colonies of honeybee from a local apiary were used in the study during springmultiplication. The honeybee colonies were randomly allocated to6groups with6replications each. One of the groups was fed no ALA adding diet as control group, and theothers were fed diet with supplementation of ALA at levels of2%,4%,6%,8%and10%,respectively, as experimental groups. The results showed that:(1) The colony intake amountof4%group was significantly higher than control group and6%~10%ALA adding groups(P<0.05), but4%group had the lowest midgut lipase activity(P<0.01).(2)2%~6%ALA levelcould effectively improve the24d and the36d colony development, and4%ALA group wasthe best(P<0.05), which, compared with the control group, increased32.63%and28.28%,respectively.(3) Compared with the control group, the emergent weight of honeybee in4%and6%ALA groups increased by7.94%and6.33%respectively (P<0.05),.However, whenALA level in diet exceeded10%, the honeybee was small. As we know, the emergent weightof honeybee is closely related with lifespan, and2%~6%ALA levels in diet strengthenedhoneybee’s longevity.Fifteen colonies of honeybee from a local apiary were used in the study during autumnmultiplication. The honeybee colonies were randomly allocated to3groups with5replications each. One of the groups was fed no ALA adding diet as control group, and the others were fed diet with supplementation of ALA at levels of4%and8%, respectively, asexperimental groups. The results showed that:(1) Lipid content in honeybee was different atall development stage. Adult honeybee in4%ALA group had higher lipid content and intakethan the other two groups (P<0.05). At the same time, larva, pupa and0d imago was moreweight in this group.(2) The total population of bee colony and total amount of sealed broodwere better than control group and8%ALA level group(P<0.05), but there was no significantdifference between control group and8%ALA level group(P>0.05).(3) The ALA levels insubstitute pollen significantly affected the fatty acid composition and lipid content of eachdevelopment stage of the honeybee. In larva and pupa stage, the ratio of UFA/SFA was lessthan2, and UFA content in experimental group was significantly higher than that in thecontrol group(P<0.05).(4) Compared with the control group, ALA level in experimentalgroup significantly reduced TG content (P=0.0099), TC content (P<0.0001) and LDL content(P=0.0143) in honeybee hemolymph, but HDL content in hemolymph was increased withALA level increased in diet (P=0.0251).(5) After honeybee feed experimental group diets, thebody three major lipid metabolism gene (FAS, ACC and LSD) expression levels decreased(P<0.05), but the gene HSL expression level increased (P<0.05).This study showed that ALA level in substitute pollen affected colony intake, colonydevelopment and emergent weight during spring multiplication and autumn multiplication,and ALA level too high or too low would have adversely effect on honeybee’ growth andlifespan.4%ALA level in diet was able to meet the nutritional needs of honeybee.Furthermore, honeybee feed the ALA-rich substitute pollen, resulting hemolymph TG, TC,LDL and HDL concentration occurred corresponding changes, and these changes regulatedhoneybee gene FAS, ACC, HSL and LSD mRNA expression level decreased or increased,thereby regulating enzyme activity and hormone levels change in the body, thus impacting onthe body lipid content and fatty acid composition to regulate the lipid metabolism. |
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