The basic study on heat stability of polyphenol oxidase (PPO) from purple sweet potato (PSP) was mainly carried out here. Research on thermal stability showed that PPO from PSP was very sensitive to the changes of temperatures. The optimum temperature of PPO was 16°C with the second optimum temperature of 30°C and PPO activity dropped rapidly when temperature was below 5°C or above 45°C. Half-lives of PPO were 450, 240, 66, 50, 21 and 13s respectively at tested temperatures from 65 to 90 °C at 5°C intervals.
[Objective] A feeding trial was conducted to estimate the optimum requirement of dietary available cobalt for juvenile Ctenopharyngodon idellus.[Method] Cobalt chloride was added to the basal diet at 0,0.1,0.2,0.4,0.8 and 1.6 mg/kg diet providing the actual dietary value 0.05(control),0.13,0.22,0.44,0.95 and 1.63 mg/kg diet respectively.Casein and gelatin were used as protein sources,dextrin as carbohydrate source and fish oil and corn oil as lipid source respectively.Each experimental diet was randomly assigned to triplicate groups of fish,and each group was stocked with 60 fish [initial body weight,(3.21±0.35) g].Fish were fed three times daily (9:00,13:00 and 18:00) to satiation for 70 days.During the experimental period,the water temperature fluctuated from 25 to 28 ℃,and dissolved oxygen was approximately 5.0 mg/L.[Result] The results showed that the weight gain rate,specific growth rate and protein efficiency ratio of the juveniles increased significantly with the increase of dietary cobalt levels (P0.05).There were no significant differences in survival rate (P0.05).Maximum weight gain,specific growth rate,protein efficiency ratio and minimum feed efficiency occurred for group at 0.22 mg/kg dietary cobalt,which were significantly different from the other five groups (P0.05).Supplementation of dietary cobalt had no significant effect on the moisture,crude protein,crude liquid and crude ash content of the juvenile (P0.05).When the juveniles were fed 0.22 mg Co per kg diet,the cobalt contents in liver,kidney and muscle reached the peak,which were significantly higher than 0.05 mg/kg group,0.13 mg/kg group and 1.63 mg/kg group(P0.05).There was no significant difference in cobalt content in liver,kidney and muscle when the fish were fed the diets of 0.22-0.95 mg Co per kg diet (P0.05).Supplementation of dietary cobalt increased hemoglobin (HGB),platelet count (PLT),hematocrit (HCT) and red blood count (RBC).These values reached the peak when the juveniles were fed 0.22 mg Co per kg diet,which were significantly higher than 0.05 mg/kg group (P0.05).[Conclusion] Broken-line regression analyses of specific growth rate and kidney cobalt against dietary cobalt level indicated that the dietary cobalt requirement for optimal growth and accumulation level of tissue cobalt of juvenile Ctenopharyngodon idellus was about 0.20 mg Co/kg diet.
The effect of the dietary immunopolysaccharide(yeast cell wall)on non-specific immune function in juvenile soft-shelled turtle(Pelodiscus sinensis)was studied.The turtles were divided into 6 groups and were fed with feed supplemented with different ratio of yeast cell wall,that was 0 mg/kg(control group),500.0 mg/kg.B.W.(group I),1000.0 mg/kg.B.W.(groupⅡ),1500.0 mg/kg.B.W.(groupⅢ),2000.0 mg/kg.B.W.(groupⅣ)and 2500.0 mg/kg.B.W.(groupⅤ) respectively.28 days later,the turtles were blooded,and the phagocytic activityof the leucocytes,serum lysozyme activity and complement activity were monitored.The results showed that the phagocytic activityand lysozyme activity in group I,Ⅱ andⅢ were significantly higher than the control group(t-test,P(0.05)).However,there were no significant differences among groupⅣ,Ⅴ and the control group(t-test,P0.05).The highest complement activity was observed in groupⅡandⅢ,which was significantly higher than the control group(t-test,P0.05).As the complement activity was concerned,there were no significant differences between group I,Ⅳ,Ⅴ and control group(t-test,P0.05).The results demonstrate that the best supplementation ratio of the yeast cell wall in the soft-shelled turtle is about 1000.0 mg/kg.B.W,and immunosuppression in soft-shelled turtles will probably occurwhen the supplementation ratio go beyond 1500.0 mg/kg.B.W.
Non-point source pollution from the Agri-sector (especially nitrogen (N)) due to the application of conventional urea with heavy rates not only depleted the water quality of Erhai Lake but also declined the nitrogen use efficiency (NUE) of different crops grown in the Erhai Lake Basin, Dali, Yunnan, China. It is imperative to mitigate the total nitrogen and its forms (nitrate (NO3−)-N and ammonium (NH4+)-N) loading to the surface and subsurface water flow through optimum fertilizer management for crop production in the region. To achieve this goal, a balanced crop nutrition system was practiced with different fertilizer types for rice-broad bean crop rotation system. The crop nutrition system consisted of No Fertilizers (CK), Conventional Fertilizer Practice (CF), Conventional urea as environmental Fertilizer (T1), Refined Organic Fertilizer applied solely (T2), Refined Organic Fertilizer applied with conventional urea (T3), Refined Organic Fertilizer applied in T2 was increased 4 times (T4), Refined Organic Fertilizer applied in T3 was increased 4 times but the same amount of conventional urea (T5), and Controlled Release Fertilizer (CRF) application (T6). The same rate of nitrogen (20% lower than CF) was applied in T1, T2, T3, and T6. All the former mentioned treatments were compared to CF with respect to different variables. In case of crop production, T6 gave maximum rice grain yield (9.9 t ha−1) and broad bean yield (5.1 t ha−1). Treatments T1 and T5 were at par for rice grain yield (7.8 t ha−1) and this quantity was not significantly lower than CF. Treatments T6, T5, and T1 were observed 29%, 47%, and 46%, respectively lower in TN loading to the surface and percolating water than the CF. Conventional urea and refined organic fertilizer combined with conventional urea at reduced nitrogen rates can be a reliable option for crop production in the Erhai Lake Basin with optimum yield under the rice-broad bean crop rotation system. CRF at reduced nitrogen rate can be a better option for higher yield and lower NO3–N, NH4+-N and total nitrogen losses to the surface runoff and leached water.
The paper briefly summarized the recent research progress of Auricularia, especially on species diversity, phylogeny and genetic diversity of cultivated species. Three issues are in desperate need of being solved in future studies: 1) lacks systematical investigation of Auricularia; 2) exploration of phylogenetic relationships among species of Auricularia; and 3) analysis of genetic diversity on the wild populations of Auricularia auricula‐judae, an important cultivated species.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)