| Myostatin(MSTN)is a negative regulator of muscle growth and development.MSTN gene edited cattle show the characteristics of fast muscle growth and strong meat production ability.However,the research on the edible safety and risk of gene editing products is very limited.This study refers to the Announcement No.323-27-2020 food safety detection of genetically modified plants and their products of the Ministry of agriculture and rural areas,and according to the standards of 90 day oral toxicity test(GB15193.13-2015)and teratogenicity test(GB15193.14-2015),in order to evaluate the food safety of MSTN gene edited beef and provide basis for further utilization and development of MSTN gene edited beef.(1)In order to study the subchronic effect of long-term feeding MSTN gene edited beef on mice,140 6-week-old Kunming mice,half male and half female,were randomly divided into 7 groups.They were fed with unedited Luxi beef(F10%,F20% and F30% groups)with10%,20% and 30% addition and Luxi beef(Z10%,Z20% and Z30% groups)with 10%,20%and 30% MSTN gene editing And commercial feed(control group),the feeding period was 90 days.During the experiment,the behavior of mice was observed,weighed every week and recorded the food intake.After the 90 day feeding period,the blood routine indexes and serum biochemical indexes of mice were detected,the organ coefficient of mice and histopathological examination were calculated.The results showed that the mice in each group had good mental state,normal behavior,no poisoning and no death during feeding;There was no significant difference in weekly weight gain and weekly food intake between male and female mice(P>0.05);There was no significant difference in average platelet volume,hematocrit,average erythrocyte volume,erythrocyte,erythrocyte distribution width,hemoglobin,average hemoglobin volume and platelet distribution width among the groups(P>0.05);Although the number of leukocytes in the control group was significantly higher than that in the Z30% group(P<0.05),the percentage of monocytes in the F10% and Z10%groups was significantly higher than that in the F20%,F30% and Z20% groups(P<0.05),the percentage of monocytes in the Z30% group was significantly higher than that in the F20% group(P<0.05),the percentage of lymphocytes in the Z30% group was significantly lower than that in the control group and F20% group(P < 0.05),and the average hemoglobin concentration in the Z20% group was significantly lower than that in the F30%group(P<0.05);Platelets in F30% group were significantly lower than those in F20%group(P<0.05),but all indexes were within the normal range.And.The results of blood biochemistry showed that there was no significant difference in triglyceride,aspartate aminotransferase,total protein,albumin and urea nitrogen among the groups(P>0.05),although the total cholesterol in the control group was significantly lower than that in other groups(P<0.05);Alanine aminotransferase in the control group was significantly higher than that in other groups(P<0.05);Glucose in the control group was significantly higher than that in other groups(P<0.05),but all indexes were within the normal range;In addition,the results showed that there was no significant difference in organ coefficient between groups after feeding for 90 days(P>0.05),and no obvious pathological changes were found in pathological sections.(2)In order to explore whether MSTN gene editing beef will affect the diversity and distribution of intestinal flora in mice,the intestinal microorganisms of mice were detected.A total of 25 6-week-old healthy male Kunming mice were randomly divided into 5 groups.After feeding different diets for 90 days,feces were collected for intestinal flora detection and analysis.The results showed that there was no significant difference in Shannon and Simpson index between Luxi beef group and MSTN gene edited Luxi beef group(P>0.05);There was no significant difference between Chao1 and ACE index(P>0.05);At the phylum level,the distribution proportion of dominant communities that can be identified in each group is Bacteroides,Firmicutes and proteobacteria.(3)In order to explore the effect of MSTN gene edited beef on fetal development of pregnant mice,10%,20% and 30% unedited Luxi beef,MSTN edited Luxi beef and commercial feed were fed to pregnant mice from day 3 to 15.The results showed that there was no significant difference in weight gain,fetal growth,embryonic development,organ weight and organ coefficient between MSTN gene edited beef group and Luxi beef group and commercial feed control group(P>0.05).In conclusion,MSTN gene edited beef obtained by gene editing technology has no adverse effects on mouse behavior,growth performance,intestinal flora and embryonic development and health during pregnancy.This experiment provides a certain reference for evaluating the safety of MSTN gene edited beef. |
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