Dietary thiamin requirement of juvenile grass carp, Ctenopharyngodon idella, was to investigate in this experiment. Eight purified diets were formulated with graded levels of thiamin (0.1, 0.6, 1.1, 2.1, 5.5, 9.8, 21.2, and 41.8 mg/kg, respectively). Each diet was fed to triplicate groups of 40 fish (initial average weight 10.7 ± 0.2 g) for 12 wk in 400‐L aquaria (R = 1 m, h = 0.6 m). Results showed that weight gain rate, specific growth rate, feed efficiency, protein efficiency ratio, and hepatosomatic indice of fish increased before dietary thiamin increased to the optimum level, then remained similar thereafter (P > 0.05). Thiamin concentration in fish liver was positively correlated with dietary thiamin and it stayed in stable when dietary thiamin level exceed 5.0 mg/kg. The serum biochemical indices analysis showed that dietary thiamin had significant effects on serum triglycerides, total cholesterol, glucose, pyruvate contents, and lactate dehydrogenase activity. Body composition was unaffected by dietary thiamin. Broken‐line regression analysis showed that, a dietary thiamin level of 1.3 mg/kg diet was adequate for optimum growth, and 5.0 mg/kg for maximum liver thiamin accumulation.

No abstract

Recent data showing the high incidence of typhoid fever in young children, the demonstration of safety and efficacy of a Vi conjugate for this age group, the safety and similar immunogenicity in infants when administrated concurrently with EPI vaccines, together with the interests of manufacturers and investigators in studying such conjugate vaccines prompted us to prepare a human IgG anti-Vi standard to facilitate this work. Volunteers were injected with an investigational Vi-recombinant Pseudomonas aeruginosa exoprotein A (Vi-rEPA) conjugate vaccine. Plasmas with the highest levels of IgG anti-Vi were pooled. The IgG anti-Vi content of this preparation, assayed by precipitin analysis with purified Vi, was 33μg/ml. Accordingly, the estimated IgG anti-Vi protective level of 3.5 ELISA unit/ml, derived from our efficacy trial of Vi-rEPA in 2-to-5 years old children, is equivalent to 4.3μg/ml. This reagent is suitable for comparison of immune response of Vi conjugate vaccines or for other purposes requiring anti-Vi titration.

A bioflocculant-producing bacterium, Bacillus megaterium SP1, was isolated from biofloc in pond water and identified by using both 16S rDNA sequencing analysis and a Biolog GEN III MicroStation System. The optimal carbon and nitrogen sources for Bacillus megaterium SP1 were 20 g L−1 of glucose and 0.5 g L−1 of beef extract at 30°C and pH 7. The bioflocculant produced by strain SP1 under optimal culture conditions was applied into aquaculture wastewater treatment. The removal rates of chemical oxygen demand (COD), total ammonia nitrogen (TAN), and suspended solids (SS) in aquaculture wastewater reached 64, 63.61, and 83.8%, respectively. The volume of biofloc (FV) increased from 4.93 to 25.97 mL L−1. The addition of Bacillus megaterium SP1 in aquaculture wastewater could effectively improve aquaculture water quality, promote the formation of biofloc, and then form an efficient and healthy aquaculture model based on biofloc technology.

The effect of the different dietary carbohydrate types and levels on growth performance, haematological indices and hepatic hexokinase (HK) and glucokinase (GK) genes expression involved in control of glucose metabolism, was studied in juvenile mirror carp (Cyprinus carpio). Two carbohydrates (glucose and starch) diets with two levels (250 and 500 g kg À1 ) were fed to triplicate groups of 35 fish for 60 days. The best weight gain rate and specific growth rate were observed in fish fed with 250 g kg À1 glucose diet and 500 g kg À1 starch diet (P < 0.05). Fish fed with 500 g kg À1 glucose showed low feed utilization, with the highest food conversion ratio and the lowest protein efficiency ratio (P < 0.05). Hepatosomatic index was significantly higher in fish fed with glucose diets and the 500 g kg À1 starch diet compared to 250 g kg À1 starch. CHOL, HDL-C and LDL-C were significantly highest in fish fed with 500 g kg À1 starch than all other diets (P < 0.05). Hepatic GK mRNA expression level and activity were positively related to glucose and starch levels (P < 0.05). Correlation analysis showed that hepatic glycogen concentration was increased by dietary carbohydrate content (P < 0.05). These results suggest that GK may play a major role in the postprandial glucose utilization in juvenile mirror carp.