Crop Straw Fermentation By Microorganism To Improve The Feeding Effect Of Musca Domestica

China is a vital agricultural country traditionally and one of the most abundant crop straw resources in the world.As such,how to effectively utilize the straw resource has become the key issue for sustainable development of agriculture in China.Straw diet is a critical component of the comprehensive utilization of crop straw,however,its high content of cellulose,hemicellulose,lignin,low nutritional components and poor palatability restrict its development to be animal diet.Thus,in this paper,we screened several microorganisms that can degrade corn straw and wheat straw effectively,formulated the artificial diets to feed on housefly,Musca domestica,and investigated the effects of fermented straw diets on rearing of M.domestica.The goal is to improve the efficiency of crop straw digestion and provide a new insight for the utilization of straw resource.The main results are as follows:1.Effect of crop straw fermentation by Bacillus subtilis on raising M.domesticCorn and wheat straw were fermented with Bacillus subtilis,and used as artificial diets for rearing of the M.domestica.The results suggested that:（1）After B.subtilis fermentation,the absolute content of cellulose,hemicellulose and lignin in corn straw were decreased 11.84%,16.67%,19.28%respectively,the absolute content of soluble sugar in corn and wheat straw were increased 93.74%and 42.48%,the absolute content of cellulose hemicellulose and lignin in wheat straw were decreased16.96%,2.64%,5.88%respectively.After M.domestica larval feeding,the absolute content of soluble sugar,cellulose,hemicellulose and lignin in corn and wheat straw were decreased significantly.（2）The optimum formulation for mass rearing of the M.domestica was as follows:corp straw and wheat bran mixed with the ratio 1:1 by weight,then followed by the fermentation with 3 ml(3.2×10¹¹cfu/ml)B.subtilis for3 days,200mg of the M.domestica newly-hatched larvae were supplied with 250g of diet.（3）It is verified that B.subtilis can colonize in the intestines of the M.domestica by PCR and q-PCR technology.B.subtilis can help the M.domestica larvae convert to crop straw.The M.domestica fed with B.subtilis fermented corn straw diet for 5 d,the relative content of B.subtilis in the intestinal is 5.64 times than control group.（4）After being used as artificial diet,the organic content of the residues of corn and wheat straw was far more than the national standard,the total content of nutrient approaches to national standards.2.Effect of mixed fermentation of crop straw with Trichoderma viride and yeast on raising M.domesticIn order to improve the degradation rate of three major components in crop straw,crop straw was fermented with T.viride and yeast,U6（6⁴）was designed by uniform experiment,and used as artificial diet for rearing of the M.domestica.The results suggested that:（1）After the mixed fermentation with T.viride and yeast,the absolute content of cellulose,hemicellulose and lignin in corn straw were decreased 30.21%,22.65%,12.17%respectively;the absolute content of cellulose,hemicellulose and lignin in wheat straw were decreased 11.13%,15.50%,10.77%respectively.Comprehensive considerations combined with cost,the best diet formulation for mass rearing of the M.domestica was crop straw mixed with wheat bran at the proportion1:1 and the amount of T.viride and yeast was 7%+1%,with fermentation time of 5days,200 mg of M.domestica newly-hatched larvae were supplied with 250 g of diet.（2）By using different diets to rear M.domestica,the conversion rate of different diets were from high to low,corn straw>wheat straw>wheat bran.The highest conversion rate was 16.19%by houseflies reared with corn straw,and the conversion rate of wheat bran was the lowest（8.89%）.3.Analysis of the nutritional quality of M.domestica larvae reared on different dietsThe nutritional quality of maggot powder made from M.domestica larvae that were previously fed with optimal diets were analyzed.Our results revealed that:When the M.domestica larvae fed with corn and wheat straw,the moisture content of the M.domestica larvae was 79.41%～81.69%,protein content was 63.17%～64.57%,fat content was 15.95%～18.56%,ash content was 7.74%～9.55%.There was no significant difference in the protein,fat and ash content of the corn and wheat straw diets compared with control group.The protein content of the M.domestica larvae was up to 64.57%,which is higher than that found in fish meal.4.Effects of maggot powder supplementation on growth performance and immunity of broilersIn order to evaluate the effects of different diets on the growth of broilers,fish meal,maggot powder and yellow mycin were added to the basal diets.The results suggested that:（1）the weight of broilers was significantly increased by the addition of maggot powder in the first two weeks.After feeding,the average daily gain of maggot powder group increased by 13%compared with control group.The feed weight ratio of control group,fish meal group,maggot powder group and antibiotic group were 1.66,1.73,1.53,1.82,and the income of maggot powder group increased by 31.75%compared with control group.（2）The results showed that the thymus index of maggot powder and antibiotic group was significantly higher than control group and fish meal group.The thymus index of control group,fish meal group,maggot powder group and antibiotic group were 4.87,4.14,6.27,5.36.The spleen index and bursa index of maggot powder group had no difference with control group,spleen index were 1.80,2.04,2.13,2.15,bursal index were 4.01,4.11,4.38,3.96.（3）The analysis of antioxidant index showed that the addition of maggot powder significantly increased the activity of GSH-PX and SOD in the serum of broilers,and had little effect on the content of MDA.In conclusion,B.subtilis,T.viride/yeast were selected as high efficient strains for straw diets.The nutrient content and utilization ratio of straw were improved.These results shows that the crop straw can be effectively transformed after fermentation with B.subtilis or T.viride/yeast and fed to M.domestica larvae.Supplementing maggot powder significantly increased the growth performance and immune function of broilers.The above results provide an important theoretical basis for the resource utilization of crop straw and the industrial development of the M.domestica.