ABSTRACT
In this study, four light color treatments (red blue, white, natural light) were tested to determine effects of light spectrum on the growth of larval Whitmania pigra (30 days old) at the same intensity. The experiment lasted for 50 days. The specific growth rate (SGR) under blue light condition was significantly higher during 30 days to 40 days. At the end of the experiment, specific growth rate (SGR) and weight gain rate under red light condition were higher (P<0.05) than those under other groups. Meanwhile, the enzymes activities of digestive enzymes (protease, amylase and lipase) were higher under red light condition. However, the enzymes activities of antioxidant enzymes (SOD, CAT, ALP) were lower under white light condition compared with the other treatments（P＜0.05）. In addition, no significant changes were observed for water content, total ash, acid insoluble ash, pH and antithrombin activity in the all treatments. After 50 days, the digestive enzymes and growth rate were higher under red light condition but antioxidant enzymes were lower under white light condition. Furthermore, light spectrum has no significant effect on the internal quality of Wh. pigra.
ABSTRACT
The biological characteristics, oxygen consumption, oxygen consumption rate, and activities of amylase, lipase and protease of Whitmania pigra at different temperature were studied by using direct observational method, the still water method and 3, 5-dinitrosalicylic acid colorimetry, right-nitrophenyl palmitate ester（ρ-NPP）colorimetry and folin-phenol method.The results revealed that with decreasing water temperature, the daily activity and the daily feeding ration were decreased. As the temperature was lowered to 4 ℃, the head and tail of Wh.pigra curved, showing a crescent-shape without feeding and daily activity. Oxygen consumption, oxygen consumption rate and digestive enzyme activities reduced along with temperature drops. The downward trend slowed below 10 ℃, began to stabilize below 4 ℃ and doesn't change with the decrease of temperature since then. During the 40 days treatment at 4 ℃, the changes of amylase were not significant, the lipase and protease activity decreased at the 20th day, and the lipase showed an slightly increase after the decrease and finally remained at a low level.In conclusions, the pivotal temperature of hibernation of Wh.pigra is 4 ℃ and the crescent shape can be considered as a symbol of hibernation.
ABSTRACT
The oxygen consumption, oxygen consumption rate and suffocation point of different quality Whitmania pigra and Bellamya purificata were determined by hydrostatic breathing room method. The effects of feeding modes on growth of W.pigra were determined by biomass. The results showed that the oxygen consumption correlated positively with the weight of W.pigra and B. purificata（P<0.05）, suffocation point increased with the increases of the weight（P<0.05）.Oxygen consumption correlated negatively with the weight of W. pigra, the oxygen consumption rate of B.purificata first increased and then decreased with the increasing of the weight. Feeding modes had no significant effects on the finial weight, SGR, WGR, death rates of W. pigra. Feeding modes had significant effects on eating ratio. It suggested that the optimum feeding frequency of W. pigra was once every three days. Scientific and reasonable feeding amount of B. purificata should be calculated based on oxygen consumption and suffocation point of W.pigra and B.purificata at every period. Meanwhile, stocking density, water area and water exchanging frequency should be taken into consideration.
ABSTRACT
The effects of stocking density and exchanging water frequency on growth, digestive enzyme activity, anti-oxidative enzyme and inner quality of Whitmania pigra Whitman were evaluated with corresponding measures. The results showed that the eventual biomass, specific growth rate, gained weight rate, activities of amylase, lipase, protease, SOD, CAT, and ALP correlated positively with stocking density and negatively with exchanging water frequency (P<0.05). Exchanging water frequency had negative correlation with ammonia nitrogen, nitrite, and hydrogen sulfide while revealed positive correlation with dissolved oxygen in the water. Stocking density and exchanging water frequency showed no significant effects on the contents of moisture, total ash, and acid-insoluble ash. It suggested that the optimum stocking density was 7.5 million per hectare and the appropriate exchanging water interval was 72 h.
ABSTRACT
The effects of harvest and different processing methods on the anti-thrombin activity of Poecilobdella manillensis were respectively studied. The indicators included processing methods (vacuum freeze drying, fresh homogenate, drying under sunlight, freezing, scalding, baking under different temperatures), different parts (entire body, cephalon, pygidium, exudate) and body weights (≤10, 10-20, 20-30, 30-40, ≥40 g). The anti-thrombin activities of P. manillensis with different processing methods were evaluated by direct anti-thrombin titration. The results indicated that the processing methods significantly affected the anti-thrombin activities of P. manillensis. Among the 11 groups, the anti-thrombin activity of P. manillensis processed with vacuum freeze drying (1 303.56 U•g⁻¹) was significantly highest than the other groups (P<0.05), and that processed with baking under 90 ℃ (15.44 U•g⁻¹) was the lowest. The anti-thrombin activity of the cephalon of P. manillensis (226.42 U•g⁻¹) was the highest, and that of the pygidium (102.12 U•g⁻¹) was lowest; the anti-thrombin activities for different body weights were significantly different (P<0.05); and among the five groups, the body weight of ≤10 g (328.86 U•g⁻¹) was the highest (P<0.05), and the body weight of ≥40 g (87.71 U•g⁻¹) was the lowest. In conclusion, harvest and different processing methods had a significant impact on the anti-thrombin activities of P. manillensis. In the study, for the optimal processing method for P. manillensis, the body weight between 20-30 g is recommended, and the vacuum freeze drying is preferred, which is followed by the drying under sunlight.