| Trace elements play an important role in animal growth and production performance.Some data indicate that the growth and reproduction of bees require trace elements of manganese,and it also has the effect on improving the antioxidant capacity of the bees and enhancing immunity.In order to further explore the effects of manganese on the growth and physiology of bees,this survey used the Italian honeybee(Apis mellifera L)as the research object.By adding different levels of manganese to the bee larvae and adult worker bees,the indoor larvae feeding test and the out-of-person adult worker bee feeding experiment were carried out,the growth and development,survival rate,physiological and biochemical indexes and related gene expression of the bees were measured and observed,so as to find out the nutritional effects and mechanisms of manganese on bees.The following experiments were carried out:The first one: The effect of manganese on the growth and development of Italian bee larvae.In the experiment,1200 larvae of the Italian honeybee were selected,randomly divided into 5 groups,and each group had 5 repetitions,each of which had 48 larvae.One of the group was the control group and fed the basic diet.The remaining 4 groups were experimental groups,and the basal diets with added manganese levels were 2.00 mg/kg,3.00mg/kg,4.00 mg/kg and 5.00 mg/kg.The 2 d worker bee larvae were housed in an indoor constant temperature and humidity incubator at a temperature of 34? and a humidity of 50%±5%.The feed was changed daily before the pupation and raised to the feathering room.Larval samples were collected for 3 d,5 d,and 7 d,and physiological and biochemical indexes and related gene expression levels were determined.The phlegm rate and emergence rate of each group were counted.According to statistical analysis,the results showed:(1)Compared with the control group,when the Mn addition level in the larvae diet was 3.00mg/kg and 4.00 mg/kg,manganese could increase the rate of bee sting and the rate ofemergence.(2)Compared with the control group,manganese increased the glucose and total protein concentration in the hemolymph of bee larvae when the Mn addition level was 3.00mg/kg(P<0.05).(3)Manganese had significant effects on arginase activity and antioxidant-related enzyme activities in the larvae of bees.When Mn added 3.00 mg/kg and4.00 mg/kg in larvae diet,the antioxidant enzyme and arginase activity in larvae increased significantly(P<0.05).(4)Manganese had significant effects on arginase gene expression and antioxidant enzyme-related gene expression of Italian bee larvae(P<0.05).When Mn was added to the larvae diet at 4.00 mg/kg,the expression of antioxidant enzymes in the larvae increased significantly(P<0.05).When Mn added 2.00 mg/kg and 3.00 mg/kg in larvae diet,the expression of arginase gene in larvae increased(P<0.05).The second one: The effect of manganese on the physiological function of the adult bees.2500 new emerged adult bees were collected and randomly divided into 5 groups with 10 repeat,each repeat take 50 bees rearing in the feeding box.One group of them was a control group and was fed with syrup diet.The remaining four groups were experimental groups fed syrup diets with Mn levels of 50.00 mg/kg,100.00 mg/kg,150.00 mg/kg,and 200.00 mg/kg,respectively.Put each group of bees into a special bee feeding device(patent number: ZL 20142 0503643.3),put 50 bees in each feeding device,put them in a constant temperature and humidity incubator,set the temperature in the incubator at 30 ?,humidity 50% ± 5%.Regularly use a syringe to feed 3 mL of different manganese levels of sugar solution,observe bee performance,remove dead bee body,and feed until the end of the experiment.Each group was sampled at 7,14 and 21 days of age,and the physiological and biochemical indexes and related gene expression levels were measured,and the survival rates of each group were counted.The experimental results showed that:(1)According to the survival curve of bees,the survival rate of the group with manganese concentration of 50.00 mg/kg and 100.00 mg/kg was significantly higher than that of the group with manganese concentration of 150.00 mg/kg and 200.00 mg/kg.(2)When the concentration of manganese added in the diet increased constantly,the manganese content of the bee body increased significantly(P<0.05).(3)Compared with the control group,the addition of appropriate concentration of manganese in the adult worker bee feed,the antioxidant enzymes and arginase activity of the isolated bees in each treatment group were significantly increased(P<0.05).(4)Manganese had asignificant effect on the expression of arginase gene and the expression of antioxidant enzyme-related genes(P<0.05).Compared with the control group,when the level of manganese added in the diet of the bees increased(50.00 mg/kg to 150.00 mg/kg),the expression of antioxidant genes in the bees also increased(P<0.05);Compared with the control group,when the dietary manganese level of bees was increased,the expression level of arginase gene in bees also increased(P<0.05).This study shows that the level of manganese in the diet affects the growth and physiology of the bees.When the proper amount of manganese is added to the bee larvae feed,and the addition level of manganese is about 2.96 mg/kg,it can improve the physiological functions of the larvae such as antioxidant capacity and immunity.When the adult bee diet is supplemented with an appropriate amount of manganese,and the manganese level is about80.00 mg/kg,it can improve the survival performance,antioxidant capacity,immunity and other physiological functions of the bees. |
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