A feeding trial was conducted in a recirculating water system to investigatethe effects of dietary protein levels on growth, feed utilization, hepatosomatic index and liverlipid deposition of juvenile red snapper, Lut...A feeding trial was conducted in a recirculating water system to investigatethe effects of dietary protein levels on growth, feed utilization, hepatosomatic index and liverlipid deposition of juvenile red snapper, Lutjanus argentimaculatus (average initial wet weight 8.0± 0.39 g and total length 3.14 ± 0.3 cm). In the experiment, six fishmeal-based diets wereformulated to contain various protein levels (20% to 45% in 5% increments), with dietary energyranging from 2210.7kJ100g to 2250.2 kJ 100g dry matter. The protein to energy ratios of diets rangedfrom 8.58 mg protein kJ^(-1) to 20.03 mg protein kJ^(-1). Diets were fed for 90 d to triplicategroups of fish stocked in 0.128 m^3 seawater tanks, 25 individuals each. The daily ration of 2% wetbody weight was offered to the fish thrice a day. The fish at the end of the study had more thanten-fold (77.0 g) increase in weight compared to the initial (8.0 g). Fish fed diets of 40% and 45%protein produced significantly (P【0.05) higher weight gain of 77.2 g and 76.5 g, and specific growthrate (SGR) of 2.65% and 2.62% than those of 67.0 g and 68.3 g, and 2.49% and 2.51% of the otherdiets. The broken-line regression of SGR against dietary protein level yielded an optimum dietaryprotein requirement of 42.6% (Y = - 1.6295 + 0.1114 X^2, P【0.05). Survival remained 100% amonggroups. Feed conversion ratio decreased from 0.45 for fish fed 20% dietary protein to 0.35 for fishfed 45% dietary protein. Nitrogen intake increased with an increase in dietary protein, which inturn resulted in an increase in nitrogen gain of fish whole body. Fish fed 40% and 45% protein dietsshowed higher (P【0.05) nitrogen gain (0.27g and 0.26g) than those (0.23g and 025g) fed all otherdiets. Gross energy intake (GEI) in fish fed 45% protein was lower (600.67kJ) than that (607.97 kJ)of 40% protein diet, though the differences were not statistically significant (P】0.05); GEI rangingfrom 677.31 kJ to 663.20 kJ at remaining four diets (20% to 35% protein) did not appear to differsignificantly (P】0.05). The highest energy gain of 518.33 kJ was obtained with fish fed 40% protein,resulting in the highest energy retention efficiency of 85.26%. The hepatosomatic index of fish feddiets of 20%, 25%, 30% and 35% protein were significantly (P【0.05) higher (2.09% to 2.57%) thanthose (1.44% and 1.41%) of fish fed diets containing 40% and 45% protein. Liver lipid contentsdecreased from 8.72% to 7.0% in fish fed dietary protein of 20% to 45% in 5% increments. Resultssuggest that the diet containing 40% to 42.6% protein with a P/E ratio of 17.6 mg protein kJ^(-1) isrequired for good growth of L. argentimaculatus weighing between 8.0 g and 85.2 g under the cultureconditions of the present study.展开更多
The Natural Forest Protection(NFP) program is one of the Six Key Forestry Projects which were adopted by the Chinese Government since the 1980s to address important natural issues in China. It advanced to protecting a...The Natural Forest Protection(NFP) program is one of the Six Key Forestry Projects which were adopted by the Chinese Government since the 1980s to address important natural issues in China. It advanced to protecting and restoring the structures and functions of the natural forests through sustainable forest management. However, the role of forest carbon storage and tree carbon pool dynamics since the adoption of the NFP remains unknown. To address this knowledge gap, this study calculated forest carbon storage(tree, understory, forest floor and soil) in the forest region of northeastern(NE) China based on National Forest Inventory databases and field investigated databases. For tree biomass, this study utilized an improved method for biomass estimation that converts timber volume to total forest biomass; while for understory, forest floor and soil carbon storage, this study utilized forest type-specific mean carbon densities multiplied by their areas in the region. Results showed that the tree carbon pool under the NFP in NE China functioned as a carbon sink from 1998 to 2008, with an increase of 6.3 Tg C/yr, which was mainly sequestrated by natural forests(5.1 Tg C/yr). At the same time, plantations also acted as a carbon sink, reflecting an increase of 1.2 Tg C/yr. In 2008, total carbon storage in forests covered by the NFP in NE China was 4603.8 Tg C, of which 4393.3 Tg C was stored in natural forests and 210.5 Tg C in planted forests. Soil was the largest carbon storage component, contributing 69.5%–77.8% of total carbon storage; followed by tree and forest floor, accounting for 16.3%–23.0% and 5.0%–6.5% of total carbon storage, respectively. Understory carbon pool ranged from 1.9 to 42.7 Tg C, accounting for only 0.9% of total carbon storage.展开更多
The author studied the issues of the present-day status of forest resources and forest management of the Selenge River Basin on the transboundary territory of the Buryat Republic and Mongolia. It is necessary to estab...The author studied the issues of the present-day status of forest resources and forest management of the Selenge River Basin on the transboundary territory of the Buryat Republic and Mongolia. It is necessary to establish a good policy for wood cutting of the main and secondary use and reforestation.展开更多
文摘A feeding trial was conducted in a recirculating water system to investigatethe effects of dietary protein levels on growth, feed utilization, hepatosomatic index and liverlipid deposition of juvenile red snapper, Lutjanus argentimaculatus (average initial wet weight 8.0± 0.39 g and total length 3.14 ± 0.3 cm). In the experiment, six fishmeal-based diets wereformulated to contain various protein levels (20% to 45% in 5% increments), with dietary energyranging from 2210.7kJ100g to 2250.2 kJ 100g dry matter. The protein to energy ratios of diets rangedfrom 8.58 mg protein kJ^(-1) to 20.03 mg protein kJ^(-1). Diets were fed for 90 d to triplicategroups of fish stocked in 0.128 m^3 seawater tanks, 25 individuals each. The daily ration of 2% wetbody weight was offered to the fish thrice a day. The fish at the end of the study had more thanten-fold (77.0 g) increase in weight compared to the initial (8.0 g). Fish fed diets of 40% and 45%protein produced significantly (P【0.05) higher weight gain of 77.2 g and 76.5 g, and specific growthrate (SGR) of 2.65% and 2.62% than those of 67.0 g and 68.3 g, and 2.49% and 2.51% of the otherdiets. The broken-line regression of SGR against dietary protein level yielded an optimum dietaryprotein requirement of 42.6% (Y = - 1.6295 + 0.1114 X^2, P【0.05). Survival remained 100% amonggroups. Feed conversion ratio decreased from 0.45 for fish fed 20% dietary protein to 0.35 for fishfed 45% dietary protein. Nitrogen intake increased with an increase in dietary protein, which inturn resulted in an increase in nitrogen gain of fish whole body. Fish fed 40% and 45% protein dietsshowed higher (P【0.05) nitrogen gain (0.27g and 0.26g) than those (0.23g and 025g) fed all otherdiets. Gross energy intake (GEI) in fish fed 45% protein was lower (600.67kJ) than that (607.97 kJ)of 40% protein diet, though the differences were not statistically significant (P】0.05); GEI rangingfrom 677.31 kJ to 663.20 kJ at remaining four diets (20% to 35% protein) did not appear to differsignificantly (P】0.05). The highest energy gain of 518.33 kJ was obtained with fish fed 40% protein,resulting in the highest energy retention efficiency of 85.26%. The hepatosomatic index of fish feddiets of 20%, 25%, 30% and 35% protein were significantly (P【0.05) higher (2.09% to 2.57%) thanthose (1.44% and 1.41%) of fish fed diets containing 40% and 45% protein. Liver lipid contentsdecreased from 8.72% to 7.0% in fish fed dietary protein of 20% to 45% in 5% increments. Resultssuggest that the diet containing 40% to 42.6% protein with a P/E ratio of 17.6 mg protein kJ^(-1) isrequired for good growth of L. argentimaculatus weighing between 8.0 g and 85.2 g under the cultureconditions of the present study.
基金Under the auspices of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05060200)National Key Technology Research and Development Program of China(No.2012BAD22B04)Visiting Professorship for Senior International Scientists of Chinese Academy of Sciences(No.2012T1Z0006)
文摘The Natural Forest Protection(NFP) program is one of the Six Key Forestry Projects which were adopted by the Chinese Government since the 1980s to address important natural issues in China. It advanced to protecting and restoring the structures and functions of the natural forests through sustainable forest management. However, the role of forest carbon storage and tree carbon pool dynamics since the adoption of the NFP remains unknown. To address this knowledge gap, this study calculated forest carbon storage(tree, understory, forest floor and soil) in the forest region of northeastern(NE) China based on National Forest Inventory databases and field investigated databases. For tree biomass, this study utilized an improved method for biomass estimation that converts timber volume to total forest biomass; while for understory, forest floor and soil carbon storage, this study utilized forest type-specific mean carbon densities multiplied by their areas in the region. Results showed that the tree carbon pool under the NFP in NE China functioned as a carbon sink from 1998 to 2008, with an increase of 6.3 Tg C/yr, which was mainly sequestrated by natural forests(5.1 Tg C/yr). At the same time, plantations also acted as a carbon sink, reflecting an increase of 1.2 Tg C/yr. In 2008, total carbon storage in forests covered by the NFP in NE China was 4603.8 Tg C, of which 4393.3 Tg C was stored in natural forests and 210.5 Tg C in planted forests. Soil was the largest carbon storage component, contributing 69.5%–77.8% of total carbon storage; followed by tree and forest floor, accounting for 16.3%–23.0% and 5.0%–6.5% of total carbon storage, respectively. Understory carbon pool ranged from 1.9 to 42.7 Tg C, accounting for only 0.9% of total carbon storage.
文摘The author studied the issues of the present-day status of forest resources and forest management of the Selenge River Basin on the transboundary territory of the Buryat Republic and Mongolia. It is necessary to establish a good policy for wood cutting of the main and secondary use and reforestation.
