Food restriction is a strategy to improve the productive efficiency of some aquatic organisms.It is expected with the implementation of food restriction programs to first reduce the feed consumption by the cultivated ...Food restriction is a strategy to improve the productive efficiency of some aquatic organisms.It is expected with the implementation of food restriction programs to first reduce the feed consumption by the cultivated species and consequently reduce the waste load in the water.In addition,there is a lower employment of labor during periods of food restriction.However,the efficiency of the feed restriction and the compensatory gain of weight by the organisms cultivated will depend on the adaptation and the characteristics of the species in question.Several methodologies have tested forms of food restriction applied to fish farming.Some of them are addressed in this review,as well as results and comparisons made with several authors on the subject in question.The purpose of this paper was to describe the main reasons for using food restriction,its implications on fish organism and to compare results from previous studies.展开更多
About 75% of the entire surface of the planet Earth is covered by water, with only about 3% of freshwater. The Amazon region has the largest freshwater basin in the world and the uncontrolled growth of the population ...About 75% of the entire surface of the planet Earth is covered by water, with only about 3% of freshwater. The Amazon region has the largest freshwater basin in the world and the uncontrolled growth of the population in this region has become a problem concerning water contamination since a large part of the region’s population obtains water from artesian wells. This study aimed to investigate some physical-chemical parameters of groundwater in the municipality of Caapiranga, Amazonas (AM), Brazil. Water samples obtained from 14 tubular wells were evaluated, as well as a sample of surface water from Lake Caapiranga that passes in front of the municipality. The vast majority of water samples showed low pH, and were of the parameters established for drinking water, aquaculture and animal watering. High levels of nitrate are also found in most samples, which indicates contamination of these waters by domestic effluents. In wells 1, 6, 9 11, and 13 the levels of nitrate were very high and can cause serious diseases in people who use this water for consumption. According to the parameters evaluated, the quality of groundwater in 5 of the 14 wells is unfit for human consumption.展开更多
The development of more adequate food programs regarding the intensity and duration of the restriction can be an effective way to minimize the effects of exaggerated food consumption and its negative consequences for ...The development of more adequate food programs regarding the intensity and duration of the restriction can be an effective way to minimize the effects of exaggerated food consumption and its negative consequences for the economy of the business.In this sense,juvenile Nile tilapia(Oreochromis niloticus)(137±3 g)were submitted to different feeding strategies in a recirculation system.Five feeding strategies were tested in subsequent weekly cycles:continuous feeding;skipping one meal a week;suppression of two non-consecutive meals a week;suppression of three non-consecutive meals a week;suppression of four non-consecutive meals a week.Productive performance,feed consumption in the post-restriction period and economic indicators were evaluated through projections and profitability analyses.Compensatory intake occurred in all tested groups,so that the total feed intake(FI)did not differ significantly between them(p>0.05).Moderate food restriction provided a linear increase in the relative gross margin for each treatment with each change in salary level,as well as greater profitability when compared to the respective control group(p<0.05).展开更多
文摘Food restriction is a strategy to improve the productive efficiency of some aquatic organisms.It is expected with the implementation of food restriction programs to first reduce the feed consumption by the cultivated species and consequently reduce the waste load in the water.In addition,there is a lower employment of labor during periods of food restriction.However,the efficiency of the feed restriction and the compensatory gain of weight by the organisms cultivated will depend on the adaptation and the characteristics of the species in question.Several methodologies have tested forms of food restriction applied to fish farming.Some of them are addressed in this review,as well as results and comparisons made with several authors on the subject in question.The purpose of this paper was to describe the main reasons for using food restriction,its implications on fish organism and to compare results from previous studies.
文摘About 75% of the entire surface of the planet Earth is covered by water, with only about 3% of freshwater. The Amazon region has the largest freshwater basin in the world and the uncontrolled growth of the population in this region has become a problem concerning water contamination since a large part of the region’s population obtains water from artesian wells. This study aimed to investigate some physical-chemical parameters of groundwater in the municipality of Caapiranga, Amazonas (AM), Brazil. Water samples obtained from 14 tubular wells were evaluated, as well as a sample of surface water from Lake Caapiranga that passes in front of the municipality. The vast majority of water samples showed low pH, and were of the parameters established for drinking water, aquaculture and animal watering. High levels of nitrate are also found in most samples, which indicates contamination of these waters by domestic effluents. In wells 1, 6, 9 11, and 13 the levels of nitrate were very high and can cause serious diseases in people who use this water for consumption. According to the parameters evaluated, the quality of groundwater in 5 of the 14 wells is unfit for human consumption.
文摘The development of more adequate food programs regarding the intensity and duration of the restriction can be an effective way to minimize the effects of exaggerated food consumption and its negative consequences for the economy of the business.In this sense,juvenile Nile tilapia(Oreochromis niloticus)(137±3 g)were submitted to different feeding strategies in a recirculation system.Five feeding strategies were tested in subsequent weekly cycles:continuous feeding;skipping one meal a week;suppression of two non-consecutive meals a week;suppression of three non-consecutive meals a week;suppression of four non-consecutive meals a week.Productive performance,feed consumption in the post-restriction period and economic indicators were evaluated through projections and profitability analyses.Compensatory intake occurred in all tested groups,so that the total feed intake(FI)did not differ significantly between them(p>0.05).Moderate food restriction provided a linear increase in the relative gross margin for each treatment with each change in salary level,as well as greater profitability when compared to the respective control group(p<0.05).
