An orthogonal experimental design OA9 （33） was used to evaluate the effects of vitamins （A, B2, and B6） on the growth and digestive ability of the juvenile Chinese soft-shelled turtle, Pelodiscus sinensis （initia...An orthogonal experimental design OA9 （33） was used to evaluate the effects of vitamins （A, B2, and B6） on the growth and digestive ability of the juvenile Chinese soft-shelled turtle, Pelodiscus sinensis （initial weight, 5.9-0.2 g）. A total of 135 turtles were divided into 9 groups, which each included 15 individuals. The results revealed that vitamin A （VA） had the strongest impacts on the growth rate and feed utilization among the three vitamins; 35,000 IU kg^-1 VA had optimal effects on the feeding intake and specific growth rate, and 20,000 IU kg^-1 VA had optimal effects on protein digestibility and the feed conversion ratio. Vitamin B2 （VB2） was essential for regulating protein deposition and the energy efficiency for growth of the turtles; 120 mg kg^-1 VB2 resulted in increased protein and energy deposition, and 180 mg kg^-1 VB2 had greater beneficial effects on the growth rate. Vitamin B6 （VB6） had important effects on protein and feed efficiency; however, VB6 at an excessive level （120 mg kg^-1） restricted turtle growth. Based on the above growth results, dietary supplementation ofVA, VB2 and VB6 at levels of 35,000 IU kg^-1, 180 mg kg^-1 and 70 mg kg^-1, respectively, were recommended for the juvenile soft-shelled turtle.展开更多
The water quality in the surface microlayer （SML） and subsurface water （SSW） in the Guangzhou segment of Pearl River, a eutrophic urban river section in China, were ana- lyzed. The spatial and temporal dynamics of...The water quality in the surface microlayer （SML） and subsurface water （SSW） in the Guangzhou segment of Pearl River, a eutrophic urban river section in China, were ana- lyzed. The spatial and temporal dynamics of nutrient concentrations, heavy metals and bac- teria were examined from two sampling sites in monthly samples throughout 2010. The mean concentrations of total nitrogen, ammonia, nitrate and nitrite were higher than 7.0 mg/L, 3.1 mg/L, 1.1 mg/L and 0.3 mg/L, while total phosphorus and orthophosphate were 0.5 mg/L and 0.1 mg/L, respectively. These results indicated that the water quality was rich in minerals and eutrophic. The mean concentrations of Mn and Fe were higher than 0.013 mg/L; and Ni, Cr and Pb were higher than 0.001 mg/L. The mean concentrations were in the order of Mn 〉Fe 〉 Ni 〉 Pb 〉 Cr. The concentrations of heavy metals in the Guangzhou segment were lower than the limit of the surface water quality standards in China and the World Health Organization （WHO）, but higher than the median values in the world＇s freshwater. The density of bacteria ranged from 3.30×10^5 to 5.23×10^6 cells/mL, and the amount of cultivable heterotrophic bac-teria ranged from 1.30×10^3 to 1.89×10^6 cfu/mL. Fecal coliform levels were beyond the V class of China water quality standard. The SML was enriched in nutrients, heavy metals and bac- teria, with the maximum enrichment factor of 3.84 for nutrients, 8.00 for heavy metals, and 3.04 for bacteria, suggesting that the water quality of the SML of the Guangzhou segment of the Pearl River was more serious than in the SSW.展开更多
基金supported by the National Natural Science Foundation of China (Nos.30972261,31172085,31272315 and 41606137)
文摘An orthogonal experimental design OA9 （33） was used to evaluate the effects of vitamins （A, B2, and B6） on the growth and digestive ability of the juvenile Chinese soft-shelled turtle, Pelodiscus sinensis （initial weight, 5.9-0.2 g）. A total of 135 turtles were divided into 9 groups, which each included 15 individuals. The results revealed that vitamin A （VA） had the strongest impacts on the growth rate and feed utilization among the three vitamins; 35,000 IU kg^-1 VA had optimal effects on the feeding intake and specific growth rate, and 20,000 IU kg^-1 VA had optimal effects on protein digestibility and the feed conversion ratio. Vitamin B2 （VB2） was essential for regulating protein deposition and the energy efficiency for growth of the turtles; 120 mg kg^-1 VB2 resulted in increased protein and energy deposition, and 180 mg kg^-1 VB2 had greater beneficial effects on the growth rate. Vitamin B6 （VB6） had important effects on protein and feed efficiency; however, VB6 at an excessive level （120 mg kg^-1） restricted turtle growth. Based on the above growth results, dietary supplementation ofVA, VB2 and VB6 at levels of 35,000 IU kg^-1, 180 mg kg^-1 and 70 mg kg^-1, respectively, were recommended for the juvenile soft-shelled turtle.
基金Foundation： National Natural Science Foundation of China, No.41173079 The Project of Department of Science and Technology, China, No.2012BAC07B05, No.2012BAD18B01 Jinan University Project, No.21612324
文摘The water quality in the surface microlayer （SML） and subsurface water （SSW） in the Guangzhou segment of Pearl River, a eutrophic urban river section in China, were ana- lyzed. The spatial and temporal dynamics of nutrient concentrations, heavy metals and bac- teria were examined from two sampling sites in monthly samples throughout 2010. The mean concentrations of total nitrogen, ammonia, nitrate and nitrite were higher than 7.0 mg/L, 3.1 mg/L, 1.1 mg/L and 0.3 mg/L, while total phosphorus and orthophosphate were 0.5 mg/L and 0.1 mg/L, respectively. These results indicated that the water quality was rich in minerals and eutrophic. The mean concentrations of Mn and Fe were higher than 0.013 mg/L; and Ni, Cr and Pb were higher than 0.001 mg/L. The mean concentrations were in the order of Mn 〉Fe 〉 Ni 〉 Pb 〉 Cr. The concentrations of heavy metals in the Guangzhou segment were lower than the limit of the surface water quality standards in China and the World Health Organization （WHO）, but higher than the median values in the world＇s freshwater. The density of bacteria ranged from 3.30×10^5 to 5.23×10^6 cells/mL, and the amount of cultivable heterotrophic bac-teria ranged from 1.30×10^3 to 1.89×10^6 cfu/mL. Fecal coliform levels were beyond the V class of China water quality standard. The SML was enriched in nutrients, heavy metals and bac- teria, with the maximum enrichment factor of 3.84 for nutrients, 8.00 for heavy metals, and 3.04 for bacteria, suggesting that the water quality of the SML of the Guangzhou segment of the Pearl River was more serious than in the SSW.
