Ultimobranchial gland of a freshwater teleost, Heteropneustes fossilis, in response to cadmium treatment

Nerium indicum, a botanical pesticide affects ultimobranchial gland of the catfish Heteropneustes fossilis

Heteropneustes fossilis were subjected to 11.27 mg L(-1) (80% of 96 h LC50 ) and 2.81 mg L(-1) (20% of 96 h LC50 ) of Nerium indicum leaf extract for short-term and long-term, respectively. After sacrificing the fish, blood was collected on 24, 48, 72, and 96 h in short-term and after 7, 14, 21, and 28 days in long-term experiment and analyzed for plasma calcium levels. Also, ultimobranchial glands (UBG) were fixed on these intervals. Serum calcium levels of H. fossilis exhibited a decline after 48 h following exposure to Nerium indicum leaf extract. This decrease continued till the end of the experiment (96 h). Ultimobranchial cells exhibited a decrease in the cytoplasmic staining response after 72 h following the treatment. The nuclear volumes of these cells were slightly decreased. These changes were exaggerated after 96 h following the treatment. Chronically exposed fish exhibited a decline in serum calcium levels of H. fossilis on day 14. The level progressively declined till the end of the experiment. Up to day 14 following the treatment there was no change in the histological structure of UBG. A decrease in the nuclear volume of ultimobranchial cells was noticed on day 21. Moreover, the cytoplasm of these cells displayed weakstaining response. The nuclear volume of these cells recorded a further decrease following 28-day treatment. Also there was noticed vacuolization and degeneration at certain places. To the best of our knowledge, the effects of any botanical pesticides on fish UBG have not been reported yet.

Alterations in blood electrolytes of a freshwater catfish Heteropneustes fossilis in response to treatment with a botanical pesticide, Nerium indicum leaf extract

The present study aimed at investigating the effects of Nerium indicum leaf extract on the blood electrolytes of Heteropneustes fossilis for short- and long term. Fish were subjected to Nerium indicum leaf extract for short term (11.27 mg/L i.e. 0.8 of 96 h LC₅₀) and long term (2.81 mg/L i.e. 0.2 of 96 h LC₅₀). Fish were killed on each time intervals from control and experimental (Nerium indicum) groups after 24, 48, 72, and 96 h in short-term exposure and after 7, 14, 21, and 28 days in long-term experiment. Blood samples were analyzed for calcium and inorganic phosphate levels. Acute exposure of Nerium indicum leaf extract caused a progressive decrease in the serum calcium levels after 48 h in fish H. fossilis, which persists till the close of the experiment (96 h). The serum inorganic phosphate levels remain unaffected till 48 h in the Nerium indicum leaf extract-exposed fish. After 72 and 96 h, the levels exhibit a decrease. Chronic Nerium indicum leaf extract treatment provoked a decrease in serum calcium levels at day 14. This decrease continues till 28 days. The serum phosphate level of the Nerium indicum leaf extract-treated fish decreases on day 14 and 21. However, on day 28, the levels become close to the normal values. We conclude that Nerium indicum leaf extract exposure alters the blood electrolytes of the fish, thus causing physiological disturbances which might affect seriously the normal vital functions, growth rate, reproduction, and their survival in nature.

Histological alterations in the ultimobranchial gland of teleost Heteropneustes fossilis in response to chlorpyrifos treatment

In this study, an experiment was performed on Heteropneustes fossilis for short-term (1.76 mg/L chlorpyrifos, i.e., 0.8 of 96-h LC50) and long-term (0.44 mg/L chlorpyrifos, i.e., 0.2 of 96-h LC50) exposure. The fish were sacrificed after 24, 48, 72 and 96 h in the short-term experiment and after 7, 14, 21 and 28 days in the long-term experiment. On these intervals, blood was collected and analysis of serum calcium was done. Ultimobranchial glands were also fixed for histological study. The serum calcium levels of H. fossilis exhibit a decline after 24 h following exposure to chlorpyrifos. This decrease continues until the end of the experiment (96 h). The serum calcium levels of chronically exposed fish exhibit a decrease on day 7. Thereafter, the levels continue to fall progressively until the end of the experiment (28 days). The ultimobranchial gland of chlorpyrifos treated fish exhibits no histological change up to 48 h. After 72 h, there is a decrease in the staining response of cytoplasm of the ultimobranchial cells. The nuclear volume of these cells is slightly decreased. After 96 h following chlorpyrifos exposure, these changes become exaggerated. In chlorpyrifos-treated fish there is no change in the histological structure of the ultimobranchial gland up to 14 days. After 21 days, the cytoplasm of ultimobranchial cells stain feebly and the nuclear volume of these cells exhibits a decrease. Following 28 days treatment, the nuclear volume of these cells records a further decrease and the gland depicts vacuolization and degeneration at certain areas.

Blood electrolytes of the freshwater catfish Heteropneustes fossilis in response to treatment with a botanical pesticide (latex of Euphorbia royleana)

The aim of the present study was to determine changes in blood electrolytes (calcium and phosphate) in the freshwater catfish Heteropneustes fossilis following short- and long-term exposure to latex of Euphorbia royleana. To investigate the effects of short-term exposure, fish were exposed to 80% of the 96-h LC(50) of E. royleana latex (2.47 mg/L) for 96 h. To assess the effects of long-term exposure, fish were exposed to 20% of the 96-h LC(50) of E. royleana latex (0.618 mg/L) for 28 days. Fish were killed after 24, 48, 72 and 96 h (short-term experiments) or after 7, 14, 21 and 28 days (long-term experiments). Blood samples were collected and sera were analyzed to determine calcium and inorganic phosphate levels. Serum calcium levels decreased progressively in H. fossilis after 48 h exposure to E. royleana latex. This decrease persisted until the end of the experiment (96 h). Serum inorganic phosphate levels in treated fish decreased progressively from 72 h. After 7 days exposure to E. royleana latex, decreased serum calcium levels were noted in H. fossilis that persisted until the end of the experiment. Serum phosphate levels were decreased in H. fossilis on days 21 and 28 of exposure to E. royleana latex. It is concluded that E. royleana latex alters the blood electrolyte content of the fish. The change in these electrolytes, particularly calcium levels, may cause disturbances in the normal vital physiological functions of the fish, its growth rate, and even its ability to survive in nature.