Toxicity studies of detoxified Jatropha meal (Jatropha curcas) in rats.

Jatropha curcas, a tropical plant introduced in many Asian and African countries is presently used as a source of biodiesel. The cake after oil extraction is rich in protein and is a potential source of livestock feed. In view of the high toxic nature of whole as well as dehulled seed meal due to the presence of toxic phorbol esters and lectin, the meal was subjected to alkali and heat treatments to deactivate the phorbol ester as well as lectin content. After treatment, the phorbol ester content was reduced up to 89% in whole and dehulled seed meal. Toxicity studies were conducted on male growing rats by feeding treated as well as untreated meal through dietary source. All rats irrespective of treatment had reduced appetite and diet intake was low accompanied by diarrhoea. The rats also exhibited reduced motor activity. The rats fed with treated meals exhibited delayed mortality compared to untreated meal fed rats (p0.02). There were significant changes both in terms of food intake and gain in body weight. Gross examination of vital organs indicated atrophy compared to control casein fed rats. However, histopathological examination of various vital organs did not reveal any treatment related microscopic changes suggesting that the mortality of rats occurred due to lack of food intake, diarrhoea and emaciation. Further studies are in progress for complete detoxification of J. curcas meal for use in livestock feed.

Effect of the carotenoid-producing alga, Dunaliella bardawil, on CCl4-induced toxicity in rats.

Dunaliella bardawil is a carotenoid-producing alga that is being considered for use in nutraceuticals. To evaluate potential protective effects of consumption of this alga, rats were treated with two different doses of D. bardawil (2.5 and 5.0 g kg(-1) body weight [bw]) as a biomass suspension daily for 14 days. Animals were tested against Carbon tetrachloride (CCl4; 2 ml kg(-1))-induced liver toxicity as measured by various biochemical marker enzymes in liver and blood. All measurements were taken 6 h following the single dose of CCl4. The results of this study show that there was a slight, but statistically significant mean serum enzyme values, with D. bardawil treatment, compared to higher mean values in animals receiving CCl4 alone. Lipid peroxidation is measured by thiobarbituric acid-reactive substance (TBARS) activity was likewise slightly less elevated with algae treatment. The results also demonstrated protection against DNA strand breaks in hepatocytes, as measured by single cell gel electrophoresis. Liver histopathology was less severe with D. bardawil treatment, supporting the apparent protective action of 14-day treatment on hepatic oxidative injury.

Stimulatory effect of honey on multiplication of lactic acid bacteria under in vitro and in vivo conditions.

The effect of honey and sucrose on lactic acid bacteria in vitro and in rat gut was studied to determine whether these organisms were affected differently by honey compared with sucrose. Under in vitro conditions, the number of Lactobacillus acidophilus and Lactobacillus plantarum counts increased 10-100 fold in the presence of honey compared with sucrose. Feeding of honey to rats also resulted in significant increase in counts of lactic acid bacteria. Although there was no significant difference in the counts of lactic acid bacteria in the small and large intestines of different groups, the honey-fed group showed a significant increase (P<0.05) in counts over the control and sucrose-fed animals. The results support the fact that consumption of honey has a beneficial effect on the physiological constitution of animals fed with it.

Influence of melatonin on blood morphology in male albino mice.

Influence of melatonin on diurnal changes in hematological profiles was examined in male albino mice, at six hourly interval. Melatonin treatment either once daily (25 micrograms at 1700 hrs) or twice daily (25 micrograms at 0900 and 1700 hrs) for two weeks resulted in an alternation in the RBC rhythm. Generally the effect was suppressive though at some times the counts were marginally increased. Total WBC counts were increased and there was apparently a change in their rhythm too. Interestingly the differential WBC counts exhibited different patterns in, once and twice daily melatonin-treated mice. Melatonin given once daily predominantly stimulated the absolute lymphocyte count whereas the twice daily regimen predominantly stimulated the neutrophil count. This perhaps is related to the varied exposures of the animals to melatonin in the two experimental setups. Erythrocyte indices like mean cell volume, mean cell hemolglobin and mean cell hemoglobin concentration in both the experiments correlated with hemoglobin and hematocrit values. It may be concluded that melatonin has a modulatory role in hemopoiesis and its rhythms. The stimulatory effect of melatonin on WBC supports its purported immunopotentiating action.

Behaviour of rats in their home cages: daytime variations and effects of routine husbandry procedures analysed by time sampling techniques.

The behaviour of laboratory rats in their home cages was observed on both the mornings and the afternoons of days when cages were cleaned and compared to days when cages were not cleaned. Two different time sampling methods, 'instantaneous sampling' and 'one/zero sampling', were used and compared. In general the rats were more active in the mornings than in the afternoons. Activity, particularly locomotion and that associated with manipulation of the bedding was increased during both the mornings and the afternoons of cleaning days. Defaecation also increased on cleaning days whereas sitting decreased. The cleaning regime appeared to have a greater effect on behaviour than did time of day and the effect of cleaning lasted for several hours after the procedure had been completed. The implications for experimental design are discussed.

Melatonin in the control of the estrous cycle of the Indian desert gerbil (Meriones hurrianae: Jerdon).

Daily administration of melatonin for 8 weeks, either in the morning (9 a.m.) or late in the afternoon (5 p.m.), resulted in significant prolongation of the estrous cycle in the Indian desert gerbil Meriones hurrianae. The gonadosomatic index increased significantly (p < 0.01) in the melatonin-treated gerbils compared to the control animals. Histological study of the ovaries revealed enlargement of follicles and corpora lutea with hypertrophied granulosa cells in the melatonin-treated gerbils in comparison to their controls. The data suggest that the mechanism involved in the gonadal response to melatonin may not be the same in the temperate and tropical species.

Light intensity and the oestrous cycle in albino and normally pigmented mice.

The effects of light intensity (15-20 lux & 220-290 lux) on the oestrous cycle of albino and normally pigmented mice were examined. The oestrous cycle of both types of mice was shorter at the lower intensity but the difference was significant only with the black mice. The proportion of albino mice from which embryos were recovered was significantly smaller than the proportion of black mice at 15-20 lux but not at 220-290 lux. No significant differences due to strain or light intensity were found in the number of embryos recovered. We conclude that pigmented mice respond in the same way as albino mice to changes in light intensity within the range normally found in laboratory animal accommodation. That is, increased light intensity prolongs the oestrous cycle and the period of vaginal cornification.