Effect Of Methomyl On Growth And Antioxidant System Of Gift(Oreochromis Niloticus) In Presence Of Mint(Mentha Haplocalyx Briq.) As Floating Bed And Methomyl Residue In Plant

Using a broad range of chemicals is an essential aspect of agricultural practice in both developed and developing nations,to increase crop production and decrease post-harvest losses,thereby maximizing agricultural income.Methomyl is a carbamate insecticide widely used for crop protection against several species of insect,spider,tikes and mites through systemic poisoning and direct contact.However,pesticide affected not only target organisms,and water resulting from agriculture activities is a matter of concern worldwide.On the other hand,a growing interest has emerged in the use of mint in aquaculture,since they are effective with fewer side effect.Moreover,mint have been reported to produce numerous bioactivity effect such as appetite stimulation,growth and antioxidant promotion.This study was conducted to investigate the effect of methomyl on growth and antioxidant system of GIFT in presence of mint as floating bed,methomyl residue in mint and nutrient removal from tilapia cultivation wastewater using mint as floating bed.The effect of chronic sub-lethal dose of methomyl on growth performance and antioxidant system in liver of GIFT(Oreochromis nilolicus)in presence of mint(Mentha huploculyx Briq.)was investigated.Juveniles of tilapia(5.1±0.2 g)were exposed to sub-lethal concentrations of 0.2,2,20 and 200 μg/L for 45 days.After 6 weeks feeding trial,weight gain(WG)and specific growth rate(SGR)were decreased significantly(P<0.05)in the group with high concentration of methomyl(200 μg/L).Feed conversion ratio(FCR)was significantly increased(P<0.05)in the same treatment(200 μg/L).In addition,hepatic antioxidant system,including Superoxide dismutase(SOD),Catalase(CAT)Glutathione peroxidase(GPx)and Reduced glutathione(GSH),were measured at two,four and six weeks after starting the experiment.Compared with control,no significant(P>0.05)changes in SOD,CAT,GPx were detected in 0.2 μg/L group.However,the results showed significant increases(P>0.05)in activities of SOD,CAT and GPx accompanied by a diminution in GSH level resulting tilapia exposure to 2,20,or 200 pg/L over the 45 day exposure.The highest rates observed in SOD,CAT,GPx and GSH were 157.63%,164.05%and 167.46%of the control respectively,and the lowest inhibition rate in GSH was 66.42%of the control.Based on our results,it can be concluded that methomyl is toxic to GIFT.Mint as floating bed can alleviate the adverse affects of methomyl,such as growth retardation and oxidative stress.It can be used as dietary supplement in aquaculture.GIFT(Oreochromis niloticus,33.70±2.65 g,11.7±0.4 cm)cultivation wastewater,which containing N and P,was treated with mint(Mentha haplocalyx Briq.)as floating bed in static system.Treatment consisted of triplicate of T1(tilapia and 50 g of wet mint),T2(tilapia and 100 g of wet mint),T3(tilapia and 200 g of wet mint)and control(tilapia without mint).In our study,NH4+-N,NO2--N,NO3--N and TP in T3 was significantly lower(P<0.05)than that in T2,T1 and control.Moreover,treatment of cultivation wastewater with mint as floating bed was capable to reduce the concentration of NH4+-N(61.90%),NO2--N(31.59%),NO3--N(59.86%)and TP(45.92%)in 20 days.More mint density removed more N and P of tilapia cultivation wastewater.Analytical method for the determination of methomyl residue in mint collected from experimental aquaculture system with known concentration of methomyl(200 μg/L)was used,this method is based on solid-phase extraction(SPE)with cleanet TPT cartridge for sample preparation followed by ultra-high performance liquid chromatography-mass spectrometry(UPLC-MS).The aim of this work is to investigate the presence of methomyl residue,and the rate of disappearance in mint.The higher initial concentration was detected in roots 79.52μg/kg and 44.54 μg/kg in leaves and stems.During the 20 days study period,the residue levels decreased steadily to be lower than half in 15 days;16.73 μg/kg in hay and 25.29 μg/kg in roots compared with time zero sample.The present preliminary results showed that the recorded maximum residue was inferior to the Chinese maximum residue limits for methomyl in food(200 μg/kg),and below the acceptable daily intake(20μg/kg)after 15 days.