Fishmeal is the most preferred source of protein in aquafeeds, but it is expensive and scarce. Hence, Achatina fulica meat meal (AFM), which is much less preferred for human consumption out of three species of African...Fishmeal is the most preferred source of protein in aquafeeds, but it is expensive and scarce. Hence, Achatina fulica meat meal (AFM), which is much less preferred for human consumption out of three species of African giant land snails, was tested as a fishmeal substitute for Clarias gariepinus growth. Five iso-nitrogenous and iso-calorific diets were formulated, in which AFM substituted fish meal at 0% (control or Diet A), 25% (Diet B), 50% (Diet C), 75% (Diet D) and 100% (Diet E). These dietary treatments were each replicated thrice in a completely randomized design experiment, using 36-L plastic tanks in which the fish were fed daily rations corresponding to 5% of their body weight, for 8 weeks. Water quality parameters in the tanks were monitored. Proximate analyses were conducted on the fish meal, snail meal and experimental diets before the feeding trials. Cost-benefit analysis of the different diets was performed. The crude protein content of AFM (69.18%) was significantly higher than that of fish meal (55.81%). There was no significant difference (P > 0.05) in the mean weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio and survival rate in fish fed Diet A and Diet B. The best protein efficiency ratio (0.77) was recorded in fish fed Diet B. Furthermore, the survival rate of fish increased with increased levels of AFM substitution. Water quality parameters were within a suitable range for tropical fish culture, indicating that the AFM did not pollute the water. The fish fed 25% AFM diet significantly (P Clarias gariepinus diets at a 25% substitution level. The aquaculture industry can thus exploit the availability of this feed resource.展开更多
We investigated a breeding population of Common Coots (Fulica atra) from April to June in 2008 and 2009.We found that each pair of coots built display platforms beside their nest in their territory during the breeding...We investigated a breeding population of Common Coots (Fulica atra) from April to June in 2008 and 2009.We found that each pair of coots built display platforms beside their nest in their territory during the breeding season.On average,3.1 (range 2-7) platforms were built by each pair of coots.Display platforms were simpler with less coverage and were significantly lower above the water surface than nests; however,their depth below the water surface was not significantly different.Platforms were primarily used for roosting,preening and mating in the breeding season,but they were also used to store animal food.In the breeding season,nest was usually built later than platforms,the use ratio (total and daily frequency) of platforms decreased after nest was built,and more mating behavior was performed on the nest than on the platform.We compared the use ratio of both sexes to the nest and platforms in different breeding phases; the results show that females used the nest more than the platforms,while males used the platforms more than the females,suggesting that females pay more attention to breeding,while males put more energy in territorial defense.Since coots are territorial during the breeding season,the platforms may play an important role in confirming and recognizing territorial boundaries.展开更多
Territory and territorial behavior of the Common Coot（Fulica atra） were studied in two breeding sites,Anbanghe Nature Reserve and Daqing Longfeng wetland,in Heilongjiang Province,China from April to October in 2008 ...Territory and territorial behavior of the Common Coot（Fulica atra） were studied in two breeding sites,Anbanghe Nature Reserve and Daqing Longfeng wetland,in Heilongjiang Province,China from April to October in 2008 and 2009.In the breeding season,the breeding pairs occupied an area and protected it throughout the reproduction,and both interspecific and intraspecific conflicts were observed.Territory activities became severe since early May,the peak of territory behaviors appeared at late May,and then declined gradually.The territorial activities level was higher than that in the nest building period than in the laying and incubation periods.The most adopted behavioral model was expelling,which was the least energy cost.The degree of territorial behavior tended to be descended since the development of breeding phase.The territory size differed from 1 333 m2 to above 5 000 m2.Wintering population was observed in Poyang Lake of Jiangxi Province.The coots gathered in the open water;however,there was no territory behavior both in the interspecies and intraspecies in wintering sites.The hypotheses why there was territory behaviors for coots both in the interspecies and intraspecies were also discussed.展开更多
2,4-Dichlorophenoxyacetic (2,4-D), glyphosate, and nicosulfuron, because of their modes of action and selectivity, are the most widely used herbicides in Ivorian horticulture. Fuels toxicity was the reason of many deb...2,4-Dichlorophenoxyacetic (2,4-D), glyphosate, and nicosulfuron, because of their modes of action and selectivity, are the most widely used herbicides in Ivorian horticulture. Fuels toxicity was the reason of many debates in the world because of their massive and uncontrolled use. They are frequently blamed for the reduction of soil fertility and terrestrial biodiversity observed in agricultural areas. In view of the debates raised by their toxicities, the use of these herbicides requires the greatest caution and clear information on the real risk incurred by the edaphic fauna by conducting ecotoxicity studies. The present study aims to evaluate the effect of 2,4-D, glyphosate and nicosulfuron herbicides on the growth and reproduction of Achatina fulica snails in microcosm. To do this, we treated each plot on which snail microcosms were placed with 2,4-D, glyphosate or nicosulfuron herbicides according to the manufacturer’s recommendations. The results showed for all the herbicides used, that after 28 days of exposure, the growth of juvenile snails was slowed down. The number of eggs laid per pair was reduced in adult snails. The egg hatchability test revealed a reduction in egg hatchability. In addition, each effect was dependent on the herbicide used. Thus, toxicity was found to be greater according to the following order: nicosulfuron ? glyphosate ? 2,4-D. From the results obtained, we concluded that 2,4-D, glyphosate, and nicosulfuron treatments under field conditions are a potential threat to the sustainability of snail species and therefore to soil life. The intensity of the effect depends on the toxicity of the herbicides used.展开更多
文摘Fishmeal is the most preferred source of protein in aquafeeds, but it is expensive and scarce. Hence, Achatina fulica meat meal (AFM), which is much less preferred for human consumption out of three species of African giant land snails, was tested as a fishmeal substitute for Clarias gariepinus growth. Five iso-nitrogenous and iso-calorific diets were formulated, in which AFM substituted fish meal at 0% (control or Diet A), 25% (Diet B), 50% (Diet C), 75% (Diet D) and 100% (Diet E). These dietary treatments were each replicated thrice in a completely randomized design experiment, using 36-L plastic tanks in which the fish were fed daily rations corresponding to 5% of their body weight, for 8 weeks. Water quality parameters in the tanks were monitored. Proximate analyses were conducted on the fish meal, snail meal and experimental diets before the feeding trials. Cost-benefit analysis of the different diets was performed. The crude protein content of AFM (69.18%) was significantly higher than that of fish meal (55.81%). There was no significant difference (P > 0.05) in the mean weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio and survival rate in fish fed Diet A and Diet B. The best protein efficiency ratio (0.77) was recorded in fish fed Diet B. Furthermore, the survival rate of fish increased with increased levels of AFM substitution. Water quality parameters were within a suitable range for tropical fish culture, indicating that the AFM did not pollute the water. The fish fed 25% AFM diet significantly (P Clarias gariepinus diets at a 25% substitution level. The aquaculture industry can thus exploit the availability of this feed resource.
基金supported by the National Natural Science Foundation of China (No. 200904012)the Jiangxi Agricultural University Research Start Fund for Doctor (09003274)
文摘We investigated a breeding population of Common Coots (Fulica atra) from April to June in 2008 and 2009.We found that each pair of coots built display platforms beside their nest in their territory during the breeding season.On average,3.1 (range 2-7) platforms were built by each pair of coots.Display platforms were simpler with less coverage and were significantly lower above the water surface than nests; however,their depth below the water surface was not significantly different.Platforms were primarily used for roosting,preening and mating in the breeding season,but they were also used to store animal food.In the breeding season,nest was usually built later than platforms,the use ratio (total and daily frequency) of platforms decreased after nest was built,and more mating behavior was performed on the nest than on the platform.We compared the use ratio of both sexes to the nest and platforms in different breeding phases; the results show that females used the nest more than the platforms,while males used the platforms more than the females,suggesting that females pay more attention to breeding,while males put more energy in territorial defense.Since coots are territorial during the breeding season,the platforms may play an important role in confirming and recognizing territorial boundaries.
基金supported by Natural Science Foundation of Heilongjiang Province (C201036)
文摘Territory and territorial behavior of the Common Coot（Fulica atra） were studied in two breeding sites,Anbanghe Nature Reserve and Daqing Longfeng wetland,in Heilongjiang Province,China from April to October in 2008 and 2009.In the breeding season,the breeding pairs occupied an area and protected it throughout the reproduction,and both interspecific and intraspecific conflicts were observed.Territory activities became severe since early May,the peak of territory behaviors appeared at late May,and then declined gradually.The territorial activities level was higher than that in the nest building period than in the laying and incubation periods.The most adopted behavioral model was expelling,which was the least energy cost.The degree of territorial behavior tended to be descended since the development of breeding phase.The territory size differed from 1 333 m2 to above 5 000 m2.Wintering population was observed in Poyang Lake of Jiangxi Province.The coots gathered in the open water;however,there was no territory behavior both in the interspecies and intraspecies in wintering sites.The hypotheses why there was territory behaviors for coots both in the interspecies and intraspecies were also discussed.
文摘2,4-Dichlorophenoxyacetic (2,4-D), glyphosate, and nicosulfuron, because of their modes of action and selectivity, are the most widely used herbicides in Ivorian horticulture. Fuels toxicity was the reason of many debates in the world because of their massive and uncontrolled use. They are frequently blamed for the reduction of soil fertility and terrestrial biodiversity observed in agricultural areas. In view of the debates raised by their toxicities, the use of these herbicides requires the greatest caution and clear information on the real risk incurred by the edaphic fauna by conducting ecotoxicity studies. The present study aims to evaluate the effect of 2,4-D, glyphosate and nicosulfuron herbicides on the growth and reproduction of Achatina fulica snails in microcosm. To do this, we treated each plot on which snail microcosms were placed with 2,4-D, glyphosate or nicosulfuron herbicides according to the manufacturer’s recommendations. The results showed for all the herbicides used, that after 28 days of exposure, the growth of juvenile snails was slowed down. The number of eggs laid per pair was reduced in adult snails. The egg hatchability test revealed a reduction in egg hatchability. In addition, each effect was dependent on the herbicide used. Thus, toxicity was found to be greater according to the following order: nicosulfuron ? glyphosate ? 2,4-D. From the results obtained, we concluded that 2,4-D, glyphosate, and nicosulfuron treatments under field conditions are a potential threat to the sustainability of snail species and therefore to soil life. The intensity of the effect depends on the toxicity of the herbicides used.
