Effects Of Sublethal Levels Research Articles

Effects of aluminum on some tissue enzymes of gills, liver and muscles in common carp (Cyprinus carpio)

The purpose of this study was to evaluate the effects of aluminum on the tissue enzymes of gills, liver and muscles in common carp. In this study, the effects of sub lethal levels of aluminum on metabolic enzymes, Aspartate aminotransferase, Alanine aminotransferase and alkaline phosphatase (AST, ALT and ALP) in organs including gills, liver and muscles of common carp (Cyprinus carpio) were evaluated after 24, 48, 72 and 96 h exposure under laboratory conditions. Tissue extracts were prepared from each group. Enzymes were measured using commercial kits and auto-analyzer Selectra-PRO. According to statistical data analysis, it was found that the activity of this enzyme in tissues increased significantly compared to that in the control group. AST enzymes in the liver and muscle increased significantly but were reduced at 96 h. ALP levels in muscle tissue significantly increased at 72 h but were reduced at 96 h. The alterations in the activities of these enzymes indicated that the presence of aluminum interfered with transamination and metabolic process in tissues. As a biomarker in various organs, it can also be useful for toxicology

Alterations in Glutathione Reductase, Superoxide Dismutase and Lipid Peroxidation of Tadpoles (Xenopus laevis) Exposed to Bonny Light Crude Oil and its Fractions

We determined the effects of sub-lethal levels of Bonny Light crude oil (WC) and its water soluble (WSF) and insoluble (WIF) fractions on malondialdehyde (MDA) and stress enzymes in tadpoles (Xenopus laevis) following two and 4 weeks exposure at different concentrations. We observed that the treatment of tadpoles with WC, WSF, or WIF decreased the weight of tadpoles, increased MDA levels, and increased superoxide dismutase (SOD) and glutathione reductase (GR) at lower concentrations of exposure and decreased the enzymes at higher doses of exposure. We found that the WC had a lesser negative effect on the parameters of tadpoles compared to the WSF. Longer exposure of tadpoles to WC, WSF, or WIF even at lower concentrations resulted in a negative effect on MDA, SOD, and GR activities The study shows that sub-lethal contaminations with WC, WSF, or WIF induces membrane lipid peroxidation and reduce the ability of tadpoles to produce SOD and GR which may have metabolic costs.

Effect of linear alkylbenzene sulphonate (LAS) on non-specific defence mechanisms in rainbow trout ( Oncorhynchus mykiss)

Linear alkylbenzene sulphonate (LAS) is among the most widely disseminated xenobiotics to enter waste streams and the aquatic environment. In the present investigation, we present a novel approach to evaluate in toxicity of LAS. The effects of sublethal levels (0.2 and 0.4 mg/l) of LAS on non-specific immune system, phagocytosis, respiratory burst and lyzosyme activity, and specific growth rate in the rainbow trout, Oncorhynchus mykiss, during a 54-day exposure were examined by a static bioassay test procedure. The phagocytic activity of leukocytes from fish exposed to 0.4 mg/l LAS statistically decreased compared with the control fish values. No significant reductions were observed in the extra-intracellular respiratory burst and lysozyme activities after exposure to LAS at any of the concentrations tested. The final body weight in fish groups exposed to the LAS were found to be significantly lower than in the control. The specific growth rate results also supported the result above. The results of this study showed sublethal doses (0.2–0.4 mg/l) of LAS caused to statistically insignificant supression of non-specific immune system mechanisms excluding phagocytosis in fish at laboratory conditions. These doses of LAS may produce potential synergism on immune system when presented with other environmental pollutants.

Comparative toxicity of two herbicides, molinate and thiobencarb, to Brachionus calyciflorus

Acute and chronic toxicity tests with the rice herbicides molinate (S‐ethyl hexahydro‐1H‐azepine‐1‐carbothioate) and thiobencarb (S‐4‐chlorobenzyl diethyl thiocarbamate) were conducted on the rotifer Brachionus calyciflorus. The 24‐hr static LC50's were 11.37 and 47.82 mg.L‐1 for molinate and thiobencarb, respectively. The effects of sublethal levels of both herbicides on the rotifer B. calyciflorus were evaluated using some demographic parameters: intrinsic rate of natural increase (r), generation time (T) and net reproductive rate (Ro). All the parameters studied decreased with increasing toxicant concentrations. The maximum acceptable toxicant concentration (MATC) was calculated for both herbicides using the intrisic rate of natural increase (r) as parameter of evaluation and the chronic data was used to calculate aplication factors (AF) of 0.062 and 0.066 mg.L‐1 for molinate and thiobencarb, respectively. Finally, the EC50 values were derived for the selected life history parameters (Ro, T, r) of B. calyciflorus after exposure to both herbicides.

Effects of dietary carbofuran on bobwhite activity patterns.

Early pesticidal research focused primarily on the determination of LD~ 0 concentrations and measuring changes in D reproductive performance and/or number and survival of offspring (BROWN 1978). More recently, research has evaluated effects of pesticides on aggression, motor activity, stress, growth response, susceptibility to disease, and other nonletha! impacts. Because of the complexity of natural ecosystems and strong selective forces operating within them, slight pesticide-induced behavioral changes could be extremely important to the survival of certain organisms. Physiological and behavioral rhythms are part of the phylogenetic make-up of an organism and have obvious ecological and biological significance (PITTENDRIGH 1961, ASCHOFF 1964). Earlier we reported on the effects of carbaryl and carbofuran on bobwhite (Colinus virginianus) food intake, body weight, and locomotor activity (ROBEL et al. 1982). Herein we report on the effect of sublethal levels of carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) on activity patterns of bobwhites.

Toluene toxicity: Effects of sublethal levels on enzyme activities in seawater adapted tilapia(Sarotherodon mossambicus Peters)

The effects of exposing seawater adapted cichlid fish, tilapia(Sarotherodon mossambicus Peters) to sublethal concentrations of toluene on the activities of lactate dehydrogenase, succinate dehydrogenase and acetylcholinesterase were studied. The activity of lactate dehydrogenase increased while those of succinate dehydrogenase and acetylcholinesterase were inhibited in most tissues of the exposed fish. The alterations in the dehydrogenases suggested that some changes in carbohydrate metabolism may have occurred. Acetylcholinesterase inhibition in brain and other tissues indicated impairment of nervous function in toluene-intoxicated tilapia.

Adoptive Behavior of Caged Pheasants Exposed to Chicks and Dieldrin

Adoption studies in 1969 and 1970 showed respectively that 37 and 49% of confined hen pheasants (Phasianus colchicus) adopted and brooded introduced chicks, 38 and 26% intentionally killed chicks, and 18 and 11% neither adopted nor killed chicks. The hens were exposed to only sound stimulus or sight-and-sound stimuli from chicks 8 to 22 days just prior to adoption tests. There was no difference in rates of adoption or killing of chicks by hens subjected to the two treatments. Stublethal doses of dieldrin had no apparent effect on chick adoption under conditions of this study. INTRODUCTION Many workers have attempted to induce parental behavior in gallinaceous birds. Stanford (1952) studied chick adoption in bobwhite quail (Colinus virginianus) for the purpose of propagation and release of adult quail with adopted broods. Most studies of parental behavior in pheasants have involved administration of hormones, especially prolactin, in an attempt to induce broodiness for stocking purposes. Breitenbach and Meyer (1959) studied pituitary prolactin levels at different stages of the reproductive cycle, and Crispens (1956) and Nelson (1963) gave injections of prolactin to hen pheasants for the purpose of propagation and subsequent release of hens and adopted broods. Goodale (1916) induced broody behavior in capons by introduction of chicks, and Burrows and Byerly (1938) were able to stimulate broodiness in domestic hens by placing them singly in cages with chicks. Ramsay (1953) stated that visual and auditory stimuli alone may trigger broodiness in fowl. He also induced broodiness in 14 bantam hens by introducing small chicks. A field study by Linder and Agee (1965) demonstrated that stimuli provided by pheasant chicks caused nesting pheasant hens to abandon their clutches. They theorized that in areas of high pheasant density the total number of young produced may be limited by the number of unattached chicks which come in contact with nesting hens. During recent years emphasis has been placed on testing effects of sublethal levels of insecticides on behavior. Sheep exposed to dieldrin exhibited a decrement in the performance of a vigilance task (Sandler et al., 1969). However, a significant effect on detour behavior in sheep could not be detected (Sandler et al., 1968). Jackson et al. (1970), studying salmon parr (Salmo salar) and yearling speckled trout (Salvalinus fontinalis), concluded that sublethal doses of DDT, per se, 1 South Dakota Agricultural Experiment Station Journal Series No. 1006. 2 Present address: Lt. Kay L. Cool, 504-52-5128, Co. A 2132 Armor, APO 09045, New York.

Food Intake and Growth of Burro Foals after 250 Roentgens of Cobalt-60 Whole-Body Gamma Irradiation

Possible late effects of sublethal levels of whole-body gamma irradiation on growth of burro foals were studied. Two trials included 31 nonirradiated foals and 32 foals that were exposed to 250 R of 60Co gamma radiation during their fourth month of life. The foals were weaned 90 days postirradiation and allotted into treatment groups based on radiation treatment, weight, sex, and size. Each group was then randomly selected to be fed a ration containing either 9 %, 14 %, or 18 % crude protein in the first trial and either 9 % or 18 % in the second trial. The length of these trials was 364 days. Criteria used to evaluate the treatments included feed consumption, body weight gains, feed efficiency, increase in height, and increase in heart girth. Least-squares analysis of these data indicated that radiation had no significant effect on any of the traits tested. There was a consistent though nonsignificant trend for irradiated foals to be less efficient in feed utilization than their nonirradiated counterparts.