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Toxicity of Fenthion in Lebaycid® to Tilapia, Oreochromis mossambicus (Peteres): effects on survival, growth and brain Acetylcholinesterace activity
Abstract
Effects of long term exposure to sublethal concentrations of organophosphorous insecticide, fenthion (used as Lebaycid®) on survival, growth and brain acetylcholinesterase (AchE) activity of fry and fingerlings of Oreochromis mossambicus, a widely distributed food fish species in the inland waterbodies of Sri Lanka were investigated. The 96h LC 50 values of fenthion for fry (0.19 - 0.26 g in body weight) and fingerlings (2.1 - 2.9 g in body weight) were 0.83 mgl -1 and 2.07 mgl -1 respectively. Exposure to sublethal concentrations of fenthion (0.1 mgl -1 and 0.2 mgl -1 for 10 weeks significantly decreased the survival and growth of fish compared to the control fish. Long term exposure to sublethal concentrations of fenthion also exerted significant inhibitory effects on brain AchE activity of fish, ranging from 26 - 29 % inhibition in the fingerlings and 38 - 40% inhibition in the fry. Upon transfer to insecticide free water for 10 weeks, AchE activity of the fry and fingerlings exposed to fenthion recovered completely but the fry stage exposed to high concentrations of fenthion continued to grow at a slower rate. The fry stage of O. mossambicus was more sensitive to fenthion exposure than fingerlings.
... Collares-Pereira & Cowx [20] reviewed various threats to freshwater fishes and ranked species introductions as the leading threat. Of the other potential threats, there is an increasing focus on pesticides in Sri Lanka, although the majority of studies have been conducted in the laboratory [21][22][23] and few are based on real exposure environments [24][25][26]. ...
Patterns of fish community composition in the Mahaweli ichthyological region of Sri Lanka were examined in agricultural tributaries of the Uma-oya catchment of the upper Mahaweli River in comparison to more pristine streams in a nature reserve in the Amban-ganga catchment. The Uma-oya catchment shows characteristics commonly observed in extensive agricultural exploitation such as impaired water quality and altered riparian vegetation. The most abundant fish species in the two regions were Garra ceylonensis, Devario malabaricus, and Rasbora daniconius, although their relative abundance differed between sites. G. ceylonensis and Neomacheilus notostigma were the only endemic fish species in common but the latter has been extremely depauperate. Endemism is higher in the reference sites (62.5%) than agricultural sites (ca. 25%); some of the reference streams showed greater diversity with unique fish species and a few species that have not been recorded previously in the catchment. The ichthyofaunal similarity between two catchments was 39% and fish species diversity was negatively correlated with stream gradients (Pearson correlation (-0.630); r 2 = 39.6% p = 0.028). Species density and biomass of G. ceylonensis and D. malabaricus were positively associated with some water quality parameters. The presence of exotic fish species were amongst the primary discriminants between human exploited and least-exploited (reference) streams. The possible negative impact of exotic Oreochromis niloticus (Nile tilapia) on indigenous G. ceylonensis is highlighted. This paper provides impetus for making several hypotheses for sustainability of stream fish assemblages in highly exploited agricultural catchments in Sri Lanka.
... RBC (Â 10 6 cells ll À1 ) WBC (Â 10 3 cells ll À1 ) tive, metabolic, immunological stress and growth retardation in all kind of living organisms [5,12,34]. In the present study, reduction in growth following fenvalerate exposure might have been from the enhanced metabolism in order to compensate for the high maintenance energy demands under pesticide stress [35][36][37][38][39]. However, the growth of the pesticide exposed fish on being fed with probiotic mixture was not much compensated, as the probiotics increased the food consumption and food conversion ratio and thereby helped to counteract the stress and hence better growth [40,41]. ...
Five experimental diets with various combinations of probiotics, namely T1 & T6 (basal feed (BF) without
probiotics), T2 & T7 (BF + Bacillus subtilis + Lactococcus lactis), T3 & T8 (BF + L. lactis + Saccharomyces
cerevisiae), T4 & T9 (BF + B. subtilis + S. cerevisiae) and T5 & T10 (BF + B. subtilis + L. lactis + S. cerevisiae)
were fed to Labeo rohita fingerlings for 30 days. Treatment groups T1, T2, T3, T4 and T5 were exposed
to Fenvalerate, at a concentration of 1.79 lg L�1. The SOD and CAT activity was significantly affected
(P < 0.01) in fenvalerate treated groups. However, the supplementation of the three-probiotic mixture
at equal concentration showed markedly reduced activity. Similarly, RBC, Hb, NBT, total protein and albumin
values were reduced significantly (P < 0.01) in the fenvalerate exposed fish as compared to the probiotic
supplemented fish. Fenvalerate exposure also showed increased serum ALP, ACP and Bilirubin
values (P < 0.01) in comparison to the non-exposed fish. Histological observations of the gills, kidney
and liver showed tissue degeneration after fenvalerate exposure, which however showed marked
recovery on the three-probiotic mixture supplementation. Therefore, these results indicate that a mixture
of multi-species probiotic supplementation in equal concentration acts beneficially in mitigating the
stressful effects of fenvalerate.
... recovered after a recovery period of 7 days (Venkateswara Rao, 2006). In the present study, there was a significant recovery in all the biochemical parameters, in liver of fish after a recovery period of 21 days. At the end of the present study, carbosulfan exposed fish had a significantly less weight gain than that of the control fish (p < 0.05).Pathiratne (1999)emphasized that the chronic exposure of fenthion significantly decreases the survival and growth of fish. Pesticide has a significant impact on the growth of fish (Kashiwada et al., 2008;Cong et al. 2006). These studies focused on the effects of the pesticides (e.g., carbaryl and diazinon) on fish under stressful conditions for longer pe ...
Catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), and selenium-dependent glutathione peroxidase (Se-GPx) activities in liver of rainbow trout (Oncorhynchus mykiss; 116.88±21.69g) were evaluated after exposing fish to sublethal concentrations (25μg/L) of carbosulfan in flow-through tanks for 60 days. During the experiment activities of CAT, SOD, GST, and Se-GPx and histopathological effects were determined once a week and once at the end of the 21 days of recovery period. All enzymes were affected by carbosulfan when compared to control fish. Fish had intracellular oedema, cell necrosis, pycnotic nucleus, and increase of sinusoidal space in the liver. After 21 days of the recovery period, all enzyme activities had returned to control levels and fish had no histological lesions in liver. Therefore all the changes observed during exposure were reversible. Results indicate that the liver CAT, SOD and GST enzymes are highly sensitive to carbosulfan as their activities altered significantly, suggesting they could be useful in predicting sublethal pesticide toxicity and useful as an indicator for assessment of pesticides in contaminated water.
... Symbol meanings: k 1 is the uptake rate constant, k 2 is the elimination rate constant, k r is the damage recovery rate constant, k k is the killing rate constant, and D 0 is the threshold of damage, a is the inverse proportion to the life-cycle duration, b is the biological parameter, k is the fitted coefficient, ET is the exposure time, R max is the maximum response of growth inhibition, n is the Hill coefficient, EC50 is the copper concentration for 50 % growth inhibition, IECx is the body burden for x % growth inhibition, W b0 and W max0 are the body mass at birth and the maximum body mass in control groups (g), respectively, A 0 is the species-specific growth coefficient in control groups, m and d are the fitted coefficients, E is the egg eclosion rate, and F mi is the proportion of mature female in stage i a Mean ± SE b Adopted from Chen et al. (2012) c Adopted from Liao et al. (2006) d Estimated from Pathiratne (1999) h Estimated from Houde (1992) and Lin et al. (2001) i Adopted from Chotivarnwong (1971) j Estimated from Riedel (1965) based on Eq. (T1-7) ...
The impact of environmentally pulsed metal exposure on population dynamics of aquatic organisms remains poorly understood and highly unpredictable. The purpose of our study was to link a dynamic energy budget model to a toxicokinetic/toxicodynamic (TK/TD). We used the model to investigate tilapia population dynamics in response to pulsed waterborne copper (Cu) assessed with available empirical data. We mechanistically linked the acute and chronic bioassays of pulsed waterborne Cu at the scale of individuals to tilapia populations to capture the interaction between environment and population growth and reproduction. A three-stage matrix population model of larva-juvenile-adult was used to project offspring production through two generations. The estimated median population growth rate (λ) decreased from 1.0419 to 0.9991 under pulsed Cu activities ranging from 1.6 to 2.0 μg L(-1). Our results revealed that the influence on λ was predominately due to changes in the adult survival and larval survival and growth functions. We found that pulsed timing has potential impacts on physiological responses and population abundance. Our study indicated that increasing time intervals between first and second pulses decreased mortality and growth inhibition of tilapia populations, indicating that during long pulsed intervals tilapia may have enough time to recover. Our study concluded that the bioenergetics-based matrix population methodology could be employed in a life-cycle toxicity assessment framework to explore the effect of stage-specific mode-of-actions in population response to pulsed contaminants.
Patterns of fish community composition in the Mahaweli ichthyological region of Sri Lanka were examined in agricultural tributaries of the Uma-oya catchment of the upper Mahaweli River in comparison to more pristine streams in a nature reserve in the Amban-ganga catchment. The Uma-oya catchment shows characteristics commonly observed in extensive agricultural exploitation such as impaired water quality and altered riparian vegetation. The most abundant fish species in the two regions were Garra ceylonensis, Devario malabaricus, and Rasbora daniconius, although their relative abundance differed between sites. G. ceylonensis and Neomacheilus notostigma were the only endemic fish species in common but the latter has been extremely depauperate. Endemism is higher in the reference sites (62.5%) than agricultural sites (ca. 25%); some of the reference streams showed greater diversity with unique fish species and a few species that have not been recorded previously in the catchment. The ichthyofaunal similarity between two catchments was 39% and fish species diversity was negatively correlated with stream gradients (Pearson correlation (-0.630); r 2 = 39.6% p = 0.028). Species density and biomass of G. ceylonensis and D. malabaricus were positively associated with some water quality parameters. The presence of exotic fish species were amongst the primary discriminants between human exploited and least-exploited (reference) streams. The possible negative impact of exotic Oreochromis niloticus (Nile tilapia) on indigenous G. ceylonensis is highlighted. This paper provides impetus for making several hypotheses for sustainability of stream fish assemblages in highly exploited agricultural catchments in Sri Lanka.
Studies on the use of indigenous or endemic fish species for the assessment of agricultural impacts on fish populations are lacking in tropical South and Southeast Asia. This paper describes the steps involved in developing an agricultural impacts assessment program focused on river health, using recent studies on wild fish in Sri Lanka. The assessment methodology includes the selection of fish species for monitoring, and development of a strategy for sample timing, sample size requirements, and selection of appropriate reference site(s). Preliminary fish sampling data from several tributaries of the Uma-oya and the Amban-ganga (Knuckles streams) from the Mahaweli River basin were evaluated and temporal patterns of gonadal recruitment were investigated for three common species: Garra ceylonensis, Devario malabaricus, and Rasbora daniconius. The data on reproductive development were statistically incorporated to evaluate appropriate sample timing and sample size requirements. For this study, we proposed a cluster gradient design with a range of assessment endpoints and suitable statistical methods; an alternate assessment in different agricultural catchments would facilitate verification. The review and preliminary data support provide a template for study design considerations for agricultural impact assessments in South and SE Asian countries.
The present study was aimed at applying condition factor (CF), brain acetylcholinesterase (AChE) and gill histology as biomarkers for detecting possible exposure/effect induced by pesticides in fish residing rice field associated waterbodies in Sri Lanka. Biomarkers of an indigenous fish, Rasbora caverii collected from five sampling sites including canals near rice fields, a river and a reservoir (the reference site) were evaluated at four sampling stages covering pesticide application periods during rice cultivation season in 2004. Results indicated that CF of the fish did not show significant alterations regardless of the sampling sites or sampling stages. Site specific differences in AChE activities of the fish were not evident either prior to application of pesticides or at 7 days after Paraquat application to the rice fields. Two days after the application of a mixture of Fenthion and Phenthoate to the rice fields, AChE activity of the fish collected from canals near rice fields was significantly depressed (65-75%) compared to the fish in the reference site. The activities remain depressed to 50-56% even at 65 days after the insecticides application. Laboratory studies showed that prior exposure of R. caverii to Paraquat (2 microg l(-1), 7 days) enhanced the extent of inhibition of brain AChE activity induced by Fenthion (3 microg l(-1)) or a mixture of Fenthion (3 microg l(-1)) and Phenthoate (5 microg l(-1)). Gills of fish collected from canals near rice fields exhibited abnormal multiple divisions at the tips of some secondary lamellae in addition to hyperplasia, hypertrophy and club shaped deformities. Results indicate that application of pesticides in rice culture could manifest a threat to native fish populations residing rice field associated waterbodies. The response of brain AChE and histological changes in the gills of R. caverii allowed differentiating sampling sites after insecticide applications to the rice fields. Hence, R. caverii may be considered as a surrogate species in ecotoxicological risk evaluation of agrochemicals in the region.
Health status of feral Nile tilapia following repeated applications of fenthion as a mosquito larvicide to selected water canals in Sri Lanka was assessed. With three spray applications of fenthion to the study sites at weekly intervals at the concentration recommended for mosquito control, condition factor and brain acetylcholinesterase activity of the fish were depressed in a time dependent manner. Prominent histopathological alterations displayed were gill hyperplasia and telangiectasis and vacoulation of hepatocytes. Observed ill health effects of fenthion on the fish demonstrate probable ecological risk to the fish populations inhabiting the water canals which receive repeated inputs of fenthion.
Exposure to 10 ppb phosphamidon depressed the feeding and conversion rate to 35 and 47% of controls; that of methyl parathion reduced the feeding and conversion rate to 27 and 43% respectively. Efficiency of the fish to convert the food into flesh was also depressed significantly when exposed to both pesticides. Inhibition of food consumption and elevated maintenance cost may be responsible for reduction in growth and conversion efficiency. Methyl parathion is more toxic. -from Authors
Exposure of a freshwater teleost, Heteropneustes fossilis, to a concentration of 14 . 625 mg per 1 (0.9 of 96 h LC50) fenthion induced muscle and hepatic glycogenolysis with concomitant hyperglycaemia at 2, 6, 12 and 48 h after treatment. The pesticide evoked an initial fall (at 2 and 6 h) and later a rise (at 48 and 96 h) in blood chloride concentration. The treatment also caused anaemia with simultaneous increase in ESR and hypo-coagulability of whole-blood. The results are compared with organophosphate poisoning in this and in other fish species.