Optimization Of Breeding Conditions And Nutritional Requirements For The Juvenile Larvae Of Black Soldier Fly

Black Soldier Fly(Hermetia illucens,BSF)can convert organic waste such as kitchen waste,livestock manure and by-products of industrial and agricultural products into high quality protein and fat for use in the feed industry,food industry and medical industry,etc.BSF industry has attracted a lot of attention globally.However,in the actual production,it is found that the low day old(1-6 days old)BSF larvae(referred to as hatchlings)have problems such as too small breeding,low survival rate and poor stability in the large-scale rearing process that seriously affect production and bring economic losses,and there is no suitable standard for reference in the process of juvenile larvae culture.In this study,experiments were conducted mainly on the culture of juvenile larvae,and the main results were as follows:1.Optimal feeding frequency and distribution of juvenile larvae.The newly hatched(<24 h)larvae were first quantified and measured at 0.018 mg per first hatch.The frequency of feeding and the amount of individual feeding during the breeding process were then determined,and it was decided to divide the juvenile larvae period into 2 stages of feeding,1 stage for the first 3 days at 1/5 of the total amount fed and 1 stage for the last 3 days at 4/5 of the total amount fed.2.Effects of water content and proportion of feeding substrate on growth and development of juvenile larvae.The optimum water content of the culture was then determined and was in the range of70-75% for all 5 different rearing substrates.The weight of the juvenile larvae was the heaviest in this water content range,the survival rate was high and not significantly different from the other treatment groups,and the feed conversion rate,yield rate and feed utilization rate were more outstanding.The optimum feed ratio was verified to suit the actual production,and the best survival rate,feed conversion rate,yield and feed utilization rate were obtained when bran:kitchen waste=1:2.The average weight of juvenile larvae was not significantly different from that of other treatment groups,so the optimal feed ratio of bran:kitchen waste = 1:2 was finally chosen.3.Intestinal bacteria promote the growth and development of juvenile.The addition of Lactobacillus campestris to the culture process can promote the growth and development of juvenile larvae,increasing the average weight of juvenile larvae by2.41 mg when added at 5% and improving survival rates,as well as inhibiting the growth of weedy bacteria.4.Determination of weight reference for the culture of juvenile larvae.Next,the reference of juvenile larvae culture was determined,and after final experiments the juvenile larvae were ready for subsequent transformation when they reached 0.02 g,when they reached their maximum larval weight after transformation,and when the pre-pupation time was not very long and suitable for practical production.The density of culture was determined according to this criterion,and the weight of the juvenile larvae obtained from culture was 0.02 g when the larval-to-feed ratio was 46larvae/g.5.The effects of nutrients and proportion on the growth of juvenile larvae.The effects of dietary protein(P)and carbohydrate(C)macronutrients on the growth and development of juvenile larvae were studied.Finally,P:C had a greater influence on the weight,utilization rate of raw materials and crude fat content of juvenile larvae.Finally,the optimal P:C in the process of breeding was explored,and finally the best development was obtained when P:C=1:2.To sum up,this study summed up a set of basic breeding scheme.This scheme can bring guidance to the actual breeding production.Under this scheme,the enterprise is provided with the breeding reference of the juvenile larvae,that is,the weight of the juvenile larvae is 20 mg.The formulation of this reference solves the current situation that there is no scheme to rely on in enterprise breeding,and can make breeding more stable.Stable survival rate and weight of juvenile larvae can make the whole production orderly and stable.On this basis,lactic acid bacteria was added to promote the growth of the larvae,and the weight and survival rate of the juvenile larvae were improved to varying degrees.Finally,the study on the nutritional requirements of the juvenile larvae can provide a research basis for the precise feeding of the juvenile larvae and the development of special feeds for the juvenile larvae.