| Aquatic products are an important source of protein for human life.Due to deterioration of the aquaculture environment,frequent aquatic diseases from large-scale and intensive stocking,inappropriate usage of fishery drugs,the quality and safety of aquatic products have become one of the focuses of society’s attention.In 2017,a special regulation plan for quality and safety of agricultural products was issued by the Ministry of Agriculture,which explicitly mentioned that special regulation work should be carried out for "three fish and two drugs",as turbot(Scophthalmusmaximus),Mandarin fish(Siniperca Chuatsi)and snakehead(Channa argus)for the key aquatic products,and Malachite green and Nitrofurans for the key drugs.Mandarin fish is one of the precious freshwater cultured fishes in China.It is a carnivorous fish and feeds on live fish and shrimps,the main aquaculture areas are from south China,east China and central China.In order to cooperate with the special regulation work of "three fish and two drugs",the content of malachite green(MG),nitrofurans(NFs),4-quinolones(4-Qs)and methylene blue(MB)in muscle of Mandarin fish sold in Shanghai aquatic markets,were determined by high-performance liquid chromatography(HPLC),the contents of Cr,Cd,inorganic arsenic As,Hg and Pb in muscles of Mandarin fish collected from mono-cultured ponds,mixed-cultured ponds and wild lakes from east China,were determined by atomic fluorescence spectrometry(AFS)and graphite furnace atomic absorption spectrometry(GFAAS),finally,the nutrients of muscle of the wild and cultured Mandarin fish were compared by determining the content of crude protein,fat,water,ash and amino acid composition.These works aimed to provide some data for quality supervision,safety assurance and healthy culture of Mandarin fish.The main results were as follows:(1)To investigate the levels of fishery drug residues in Mandarin fish from aquatic markets in Shanghai.High-performance liquid chromatography(HPLC)was used to determine the four categories of malachite green(MG),nitrofuran(NFs),4-quinolone(4-Qs),and methylene blue(MB)on 72 samples of Mandarin fish which sold in the Shanghai wholesale market between April 2018 and March 2019.The results showed that malachite green,leucomalachite green,furazolidone,and furaltadone were not detected,nitrofurazone and furadantin accounted for 50% of the sample,4-quinolones accounted for 76.39%,and methylene blue accounted for 15.3%.The detected concentration of NFs(furazolidone 0/72,furaltadone 0/72,nitrofurazone 8/72,furadantin 32/72),4-Qs(enrofloxacin 13/72,ciprofloxacin 51/72,norfloxacin,7/72)and MB(11/72)were(0,0,0.49±0.03,3.51±2.27)μg·kg-1,(27.95±4.17,20.98±6.85,25.52 ±10.36)μg·kg-1,and 120±14 μg·kg-1(wet weight),respectively.The detection of NFs was mainly concentrated between October and April of the following year,the MB was concentrated between April and September,and the 4-Qs was mainly concentrated between April and October,but the furadantin can be detected all the year.The above results indicated that there are still some banned and restricted fishery drugs existed in Mandarin fish from aquatic markets in Shanghai,and there is a seasonal difference for different drug residuals.(2)To understand the current situation of heavy metal contents in the muscles of Mandarin fish in east China.Sixty Mandarin fish were collected from 10 sampling sites in Nanchang,Chizhou,Chuzhou,Nanjing,Yangzhou and Jiande,the contents of five heavy metals(Cd,Cr,Pb,As and Hg)were detected,and their food safety and health risk were evaluated.The results showed that the detection rate and the rate of over standard of heavy metals in all samples reached 98.67%,and 11.67%.The over standard rate of Pb(17 samples),Cd(9 samples)and as(9 samples)was 5.67%,3% and 3%,respectively.The over standard concentration of Pb,Cd and As were(0.612±0.111),(0.181±0.031),and(0.118±0.008)mg·kg-1(wet weight),respectively.71.43% of the over-standard samples were from the wild fish.Cr and Hg content were below the national standard(GB 2762-2017).The distribution of heavy metal contents has consistency(Pb>As>Cr=Cd>Hg)in different regions.The contents of heavy metal in wild fish were higher than the cultured(P<0.05),but there was no obvious difference between the mono-cultured fish and mixed-cultured fish(P>0.05).The edible safety of heavy metals with maximum exposure in mandarin fish was acceptable,based on the model of health risk assessment recommended by USEPA.However,the content of Pb and As accounted for 14.42% and 21.54% of provisional tolerable weekly intake(PTWI),respectively.The result of health risk assessment indicated that the ingestion risk of heavy metals was below the maximal acceptable level(5×10-6 a-1)recommendation by International ICRP.In summary,the food safety of wild mandarin fish was lower than that of cultured fish,but the health risk was in opposite.(3)Comparison of muscle basic nutrients in cultured and wild mandarin fish.A total of sixty fish samples of cultured and wild fish,which collected from ten sampling locations(Nanchang,Chizhou,Chuzhou,Yangzhou,Nanjing,Jiande)in East China,were investigated to detect crude protein,crude fat,moisture,ash and amino acid content,and evaluate their nutritional values.The results showed that the protein content of wild fish(18.87%)was significantly higher than the cultured(17.21%)(P<0.05),and the crude fat content(1.13%)was significantly lower than the cultured(1.30%)(P<0.05),no obvious difference between wild fish and the cultured in moisture(80.17%,79.29%)and crude ash(1.15%,1.12%)(P>0.05).The first limiting amino acids of both cultured fish and wild was methionine + cysteine,and the second limiting amino acids was valine.The essential amino acid index of the wild fish(EAAI,82.97)was higher than the cultured(EAAI,78.59),and the EAA/TAA,EAA/NEAA(40.42%,67.86%)was similar to the cultured(40.83%,67.74%).The amino acid composition of wild and cultured fish were in line with the FAO/WHO standard ideal model(EAA/TAA ≥ 40.00%,EAA/NEAA ≥ 60.00%)and they belonged to high quality protein source.In summary,the protein content of the wild fish was higher than the cultured,the fat content was lower than the cultured,and the essential amino acid index was higher than the cultured.It indicated that the value of muscle nutrition of wild mandarin fish was higher than the cultured in East China. |
PDF Full Text Request