Toxicological Effect Of Aqueous Extract From Camellia Oleifera Seedcake On Cyprinus Carpio

Camellia oleifera seedcake was used as a plant molluscicide to control Oncomelania hupensis. The aims of the present study were to assess the toxicological effect of water extract from Camellia oleifera seedcake on common carp (Cyprinus carpio). It was a safe evalution of Camellia oleifera seedcake to common carp. Furthermore, we tried to provide the scientific evidence to use Camellia oleifera seedcake killing Oncomelania hupensis. In the toxicity tests, water extract from Camellia oleifera seedcake was used as the experimental toxicant and common carp as the experimental creature. The main conclusions were summarized as follow:Water extract of Camellia oleifera seedcake had a certain effect on the hatching of common carp embryos. The hatching success significantly decreased in response to concentrations of the toxicant increasing, above 20.0 mgL^-1. When at 50.0 mgL^-1, all the embryos died before they were hatched. There was no effect on the time to hatch and visible teratogenic effect.The acute toxicity tests on the different developmental stages of common carp showed that: the fries (30g) was the most sensitive to the toxicant, the embryos was the opposite one. The 96h LC50 values for common carp embryos, the newly hatched larvae and the fries were estimated at 36.15, 11.0 and 10.98 mgL^-1, respectively. So water extract from Camellia oleifera seedcake was considered as lowly toxic, according to the different developmental stages of common carp.The subacute toxicity test (exposed 21 days) showed that: in different low concentration of the toxicant (1/10, 1/6, 1/4, 1/3 and 1/2 of 48h LC₅₀), the effects on haematological biochemical indices, frequencies of micronuclei in erythrocytes and pathological changes of. common carp (100g) were obvious. Compared with the control, the effect of the toxicant on haematological physiological and biochemical indices were significant. The RBC numbers and Hb content reduced, appearing anaemia. Erythrocytes became smaller, because of immature erythrocytes increasing in the peripheral blood. Na⁺ and Ca²⁺ concentrations in serum dropped obviously, so the balance of serum electrolyte interrupted. Total serum protein (TP) and glucose (GLU) contents decreased, but blood urea nitrogen (BUN) increased, which affected the metabolite in serum. Glutamic-oxalacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT) and alkaline phosphatase (ALP) activities increased notably, which indicated pathological changes were obvious. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were slightly activated at the beginning and then restrained, especially in the higher concentration groups, which caused active oxygen damage. At the 3rd day, the indices didn't change greatly, but since the 7th day, most of them changed notably, especially in the highest group.The toxicant had a certain mutagenic activity on common carp. Exposing in higher concentration and with longer time, the frequencies of micronuclei in erythrocytes significantly increased. The results of routine tissue dyeing assay indicated that pathological changes in different tissues were obvious. Hyperaemia, swell, curve, hyperplasia formed cell splate and slough in the gill lamella epithelium. Blood vessels of the gill lamella congested, as well as blooded-swollen in some areas. Swell, fatty and vacuolar degeneration in the liver cells. And partial putrescence of liver tissue. The area of the pathological changes in liver tissue began from margin to the central. Hyperemia, swell, vacuolar and desquamated degeneration in the nephric tubular epith epithelium. And the atrophy of glomerulus. Pathological changes were notably in the highest group at the 7th day; and the influences became severity with the time extending. The lower groups were not obvious, even though in the end of the test.