Effects Of Wheat Germ As Diet’s Protein Source On The Honeybee (Apis Mellifera L.)

Protein plays an important role in the reproduction of bee colonies in early spring.In practical production,it’s necessary to feed pollen substitutes to satisfy the growth and reproduction of the swarm.Due to the lack of pollen in the honeycomb during spring,wheat germ has some advantages as protein feed.For example,the protein content is high,the nutrition is rich.In addition to this,the wheat germ is used in piglets and fish.In this research,the swarm of potential,feed intake,worker bee birth weight,lifetime,true nutritive value,crude protein content of bee body,mesenteric development,intestinal digestive enzyme activity and gene expression were measured by adding different levels wheat germ in substitute pollen to explore the influence on honeybees(Apis mellifera L.).This research provided a theoretical basis and reference for formulating feeding standards and compound honeybee substitute pollen.Experiment 1: The effect of wheat germ as feed protein source on the digestibility of Apis mellifera L.750 newly emerged workers(<24 h old)in 15 cages were randomly and equally divided into five groups(n = 3 cages in each group,each cage contained 50 workers).The control group was fed pollen substitutes without wheat germ,and the experiment groups were fed diet with supplementation of wheat germ at levels of 25%,45%,65% and 83.74%,respectively.The raw materials of pollen substitutes were composed of wheat germ,rape pollen,sucrose and premix.Determine the digestibility of 6 – day old worker bee for different pollen feeds.Statistical analysis shows that,the rate of worker bee protein digestion showed a downward trend with the addition of wheat germ level and the control group had the highest digestibility(P<0.05).Experiment 2: Test two: The effects of wheat germ as feed protein source on bee colonies in Apis mellifera L.during the spring.The honeybee colonies were randomly allocated to 5 groups with 3 replications each.The control group was fed pollen substitutes without wheat germ,and the test groups were fed diet with supplementation of wheat germ at levels of 25%,45%,65% and 83.74%,respectively.The raw materials of pollen substituteswere composed of wheat germ,rape pollen,sucrose and premix.During 36 days trial,the feeding amount of the colony was recorded every 3 days,and the colony potential was recorded every 12 days.On the 21 st day,the birth weight of new bees was measured and then numbers of new bees were marked.The marked bees were dissected to observe the development of intestinal tissue after 14 days.The marked bees were dissected to measure the digestive enzyme activity of midgut at 1,7 and 14 day after marking.The marked bees were removed the intestine to measure the crude protein content of bee body at 1,7 and 14 day after marking.And the marked bees were dissected to measure the mRNA expression levels of SOD1,SOD2,CAT at the 1 and 14 day.Statistical analysis shows that,(1)Experimental groups with 65%,83.74% wheat germ level could significantly decreased feed intake than the other groups(P < 0.05).(2)Experimental groups with 65%,83.74% wheat germ level could significantly decreased feed intake than the other groups(P < 0.05).(3)Experimental group with 45% wheat germ level could improve significantly the mesenteric tissue development situation than control group(P < 0.05)and could improve significantly the birth weight than25% test group(P < 0.05).(4)Experimental groups with 45% and 65% wheat germ level could improve significantly the crude protein content of bee body than 25% test group,45%test group(P < 0.05)and could improve significantly the midgut proteinase than other groups(P < 0.05),indicated that adding the appropriate proportion of wheat germ can improve the crude protein content of bee body and stimulate the activity of mesenteric protease.(5)There was no significant effect on the expression of SOD1 in bee colonies(P > 0.05),but the expression of other genes was significantly affected(P < 0.05).This study showed that,with the increase of the proportion of wheat germ in the pollen feed,the rate of digestibility was decreased.Pollen feed was prepared with different proportion of wheat germ to feed normal bee colonies,and the increase of the proportion of wheat germ was reduced.The proportion of wheat germ in the pollen feed affected the growth of honeybee population,the worker bee birth weight,the crude protein content of bee body,the intestinal tissue development in the worker bees and the protease activity in the middle intestine.Wheat germ can be used as the protein source for bee pollen feed,and the appropriate proportion of wheat germ in pollen feed is about 45% to 65%.