title: Pesticide-contaminated feeds in integrated grass carp aquaculture: toxicology and bioaccumulation.
abstract: Effects of dissolved pesticides on fish are widely described, but little is known about effects of pesticide-contaminated feeds taken up orally by fish. In integrated farms, pesticides used on crops may affect grass carp that feed on plants from these fields. In northern Vietnam, grass carp suffer seasonal mass mortalities which may be caused by pesticide-contaminated plants. To test effects of pesticide-contaminated feeds on health and bioaccumulation in grass carp, a net-cage trial was conducted with 5 differently contaminated grasses. Grass was spiked with 2 levels of trichlorfon/fenitrothion and fenobucarb. Unspiked grass was used as a control. Fish were fed at a daily rate of 20% of body mass for 10 d. The concentrations of fenitrothion and fenobucarb in pond water increased over time. Effects on fish mortality were not found. Fenobucarb in feed showed the strongest effects on fish by lowering feed uptake, deforming the liver, increasing blood glucose and reducing cholinesterase activity in blood serum, depending on feed uptake. Fenobucarb showed increased levels in flesh in all treatments, suggesting bio-concentration. Trichlorfon and fenitrothion did not significantly affect feed uptake but showed concentration-dependent reduction of cholinesterase activity and liver changes. Fenitrothion showed bioaccumulation in flesh which was dependant on feed uptake, whereas trichlorfon was only detected in very low concentrations in all treatments. Pesticide levels were all detected below the maximum residue levels in food. The pesticide-contaminated feeds tested did not cause mortality in grass carp but were associated with negative physiological responses and may increase susceptibility to diseases.
authors.affiliation: Life Science Center, and Institute of Soil Science and Land Evaluation, Biogeophysics, University of Hohenheim, 70599 Stuttgart, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Pucher
authors.forename: T
authors.initials: T
authors.lastname: Gut
authors.forename: R
authors.initials: R
authors.lastname: Mayrhofer
authors.forename: M
authors.initials: M
authors.lastname: El-Matbouli
authors.forename: P H
authors.initials: PH
authors.lastname: Viet
authors.forename: N T
authors.initials: NT
authors.lastname: Ngoc
authors.forename: M
authors.initials: M
authors.lastname: Lamers
authors.forename: T
authors.initials: T
authors.lastname: Streck
authors.forename: U
authors.initials: U
authors.lastname: Focken
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D002219:Carbamates / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity; D002347:Carps; D005247:Feeding Behavior; D005278:Fenitrothion / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity; D005393:Fish Diseases / Q000139:chemically induced; D007306:Insecticides / Q000493:pharmacokinetics / Q000633:toxicity*; D014236:Trichlorfon / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity; D014874:Water Pollutants, Chemical / Q000633:toxicity; D015430:Weight Gain / Q000187:drug effects
chemical_list: D002219:Carbamates; D007306:Insecticides; D014874:Water Pollutants, Chemical; C019276:BPMC; D014236:Trichlorfon; D005278:Fenitrothion