Deleterious changes in metabolism, growth performance and body composition may be observed if fish are constrained to swimming continuously or intermittently at over-speeds. Fish Hemoglobin and red blood cells at 1. Key words: body composition, exercise, fish growth, hematology, sustained swimming. There is a direct relationship among fish health, nutrient assimilation, ability to respond to diet changes and body composition Shearer, ; Jobling, The body composition BC of fingerling fish age while lipid contents increase, but proteins are a fixed fraction in fish carcass Yogata and Oku, ; Rasmussen, ; Weatherley and Gill,
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Deleterious changes in metabolism, growth performance and body composition may be observed if fish are constrained to swimming continuously or intermittently at over-speeds. Fish Hemoglobin and red blood cells at 1. Key words: body composition, exercise, fish growth, hematology, sustained swimming. There is a direct relationship among fish health, nutrient assimilation, ability to respond to diet changes and body composition Shearer, ; Jobling, The body composition BC of fingerling fish age while lipid contents increase, but proteins are a fixed fraction in fish carcass Yogata and Oku, ; Rasmussen, ; Weatherley and Gill, Enhancement of food conversion and growth rate is fundamental in aquaculture operations.
Both endogenous factors are directly related to size and body mass. Among exogenous factors, food intake is also critical. For instance, dietary lipid composition is reflected There is a direct relationship among fish health, nu-in quality and fatty content of fillet, which is basically trient assimilation, ability to respond to diet changes and protein Kiessling et al. Culture environment ver body composition Shearer, ; Jobling, The sus habitat, or rest state versus exercise condition are also body composition BC of fingerling fish age while lipid relevant external factors Rasmussen, Fish culture contents increase, but proteins are a fixed fraction in fish under sustained swimming may result in growth stimucarcass Yogata and Oku, ; Rasmussen, ; lation, increased protein synthesis, feeding efficiency, Weatherley and Gill, Enhancement of food con-glycogen storing, lipid increase in liver and muscle, inversion and growth rate is fundamental in aquaculture creased haemoglobin concentration, reduced aggressive-operations.
Both endogenous factors are directly related ness Davison and Goldspink, ; Johnston and Moon, to size and body mass. Hackbarth and Moraes, , improvement of meat quality Bugeon et al. Therefore, it is interesting to evaluate the relevance of exercise intensity on body composition, growth and hematological profiles of juvenile matrinxa submitted to sustained swimming. Next, fish were parted into uniform-sized groups Fish were individually tagged with a microchip for posterior assessment of individual growth.
Tanks were supplied by biologically filtered water under controlled temperature. Since the tangential speed decreases from the edge to the centre of cylindrical containers, these columns allowed fish to swim into a circular, narrow water column under constant, regular speed. Water parameters were checked three times a week and the average values during the trials were: temperature The fish were acclimated in such system for one week before trials.
Fish ordinarily swam counter water flow. The water speed was monitored at distinct positions and adjusted as needed each two weeks. The water speeds were 0 control , 1. At the end of trial, feeding was discontinued for 24h; 10 fish were randomly sampled from each tank and blood samples drawn from the caudal vein in heparinized syringe.
Hematocrit Collier, , total haemoglobin Drabkin, , and red cell counting Lima et al. Data concerning the Uniformity Index were submitted to angular transformation before analyses.
The growth of matrinxa was affected by the swimming speed. No significant differences were observed on body weight of fish kept at 1. The increase of the swimming speed from 1. Fish kept at 1. Condition factor was higher 1. Fish encouraged swimming at 1. The most efficient feed conversion and the highest daily weight gain was observed at 1. Fish kept in flowing water systems at different speeds positioned against the water flow showing typical reofilic, schooling behavior, crowding near tank bottom.
Fish surfaced usually only at feeding time during the day but dispersed across the entire water column during the night. Fish swimming at 1. No variations were detected in the other hematological parameters Table 2. Protein content of white muscle of fish kept at 1.
Red muscle of fish encouraged to swimming at 1. However, there are not enough data which may elicit evaluating the relevance, for instance, of effects of exercise intensity in body composition of the species. Matrinxa originally inhabits river rapids and otherl well-aerated, flowing water courses, and has a fusiform shape with excellent hidrodynamic performance, well suited for exercise physiology studies Zaniboni Filho et al.
As stated, sustained swimming at 1. Growth performance of fish swimming at 2. Comparative studies with wild populations of lotic species have shown that these are better swimmers than lentic species Davison, Previous studies with matrinxa have shown that fish reared for 72 days at 1. Some salmonids submitted to sustained swimming at moderate speeds were shown to present better growth performance Davie et al. The maximum growth rate in this group of species is reached at 1.
Juvenile striped bass Morone saxatilis also present the best growth performance at moderate swimming speeds of circa 0.
In addition to the best growth performance, homogeneity of the fish stock is a very important farming characteristic.
Accompanying the homogeneity index Furuya et al. Exercise seems to reduce this adverse effect. Size homogeneity is also observed in salmonids endured swimming as compared to non-exercised fish Jobling et al.
In lentic waters some fingerling fish tend to eat more, therefore growing faster and precociously reaching juvenile stage. In addition, factors as individual, genetic differences may contribute for the size heterogeneity. The assembly of genetic traits results in the development of specimens better suitable for best food conversion, adaptation to the farming environment and resistance to stressing agents.
Specimens bearing such set of traits are usually called head-water fish in opposition to the retardatory ones Jobling et al. In addition to such intrinsic factor, proper fish farming management are essential. The feeding practices and stocking density can affect homogeneity.
High stocking density and inadequate feed allowance will result in higher competition so hampering size uniformity. Hence, larger, dominant and more aggressive fish eat more and hold back the submissive fish Carter et al. Sustained swimming can reduce such undesirable effect Jobling et al. Salmonids submitted to intense water flow find their bearings against the flow forming schools and reducing conflict occurrences Christiansen and Jobling, The behavior of matrinxa submitted to continuous swimming was noticeably changed.
The fish were tranquil, swimming in schools during the light periods and spreading during the dark. Considering such behavior was accompanied by increased size homogeneity, it is fair to infer that competition was reduced, that is, this behavior more likely resulted in uniform food intake, maximizing growth rate. The exercise resulted in adaptive responses at hematological level.
Regardless of being discreetly higher among the most exercised fish, these parameters were significantly higher in those submitted to 1. The metabolic demand imposed by different swimming speeds should have contributed to this effect. Hemoglobin concentration is reportedly higher in exercised matrinxa, so these observations strongly suggest that matrinxa is responsive to exercise concerning hematological profile.
Other relevant element to be considered is the fact that matrinxa originally inhabits lotic environments. There is a correlation between red blood cells size and oxygen transport capacity Lay and Baldwin, Particularly, there is an inverse correlation between red blood cells size and the fish ability to aerobic swimming.
High Hb concentration and smaller red blood cells volume is observed in the family Carangidae, active swimmers characterized by well developed red muscles fitted to hold sustained swimming. Sedentary species, typical from lentic environments, present low Hb concentrations associated to large red blood cells.
Furthermore, they present a poorly developed red muscle, which are quickly exhausted during burst-swimming Lay and Baldwin, Even though it is known that factors such as sustained swimming can effective alter BC improving productivity, most correlated works focus in nutritional composition of diets, especially in regard to effects of sources and levels of protein, lipid and carbohydrate on BC.
Changes in such parameter resulting from sustained swimming depend not only on diet composition but also on exercise intensity and fish size Rasmussen, ; Kiessling et al. Remarkable changes were observed in the BC of matrinxa submitted to increasing swimming speeds. Such changes are directly related to metabolism adaptations. Previous work has shown that matrinxa's metabolism is responsive to sustained swimming Hackbarth and Moraes, A small increase in protein content was observed in matrinxa enduring 1.
Such protein deposition resulted from the best feed conversion. Changes in body composition versus exercise seem to be dependent on fish species, feeding, and intensity and duration of the exercise Davison, The muscle phenotypic plasticity is very expressive in response to exercise, and the muscle protein delivery is a result of muscle fiber hypertrophy Totland et al.
Concerning the lipids, its deposition increased and the reduction of water content, either in red muscle or liver of fish submitted to swimming speed of 1. Similar results were observed in white muscle of brown trout Salmo trutta submitted to sustained swimming at 1. At higher speeds, up to 3. In Arctic charr Salvelinus alpinus kept under sustained swimming Christiansen et al.
The same pattern of response was observed in matrinxa. However, matrinxa presented an opposite response, since the adaptations observed to the swimming speed were reflected in enhanced body weight and increased lipid stores in the liver, red and ventral muscle, making up for metabolic, energetic demands.
Moreover, the crude energy contents increased in the liver, white and red muscle of fish under sustained swimming. In conclusion, juvenile matrinxa grew better and more homogeneously under sustained swimming of 1. The species' hematological parameters and BC were enhanced in response to the metabolic demand imposed by swimming, and these responses are tissue specific, that is, protein deposition and the energy storage, particularly lipids, increased in response to the swimming speeds in the white muscle, ventral muscle and liver.
A; Fracalossi, D. M; Fim, J. Revista Brasileira de Zootecnia
We'd like to understand how you use our websites in order to improve them. Register your interest. Brycon amazonicus is widely distributed in the Amazon basin. The species has traditionally been the focus of subsistence and commercial fisheries, and recently has become an important aquaculture species. Aquaculture relies on the removal of individuals from nature which form the basis of breeding stocks.
Brycon is a genus of fish in the family Characidae found in freshwater habitats in Central and South America , ranging from southern Mexico to northern Argentina. They feed heavily on fruits and seeds, but also take other plant material, invertebrates and small fish. Brycon support important fisheries and based on a review by IBAMA , they are the fifth most caught fish by weight in the Brazilian Amazon. There are currently 46 recognized species in this genus: . From Wikipedia, the free encyclopedia. Species of Brycon in FishBase. October version.