Densidade de estocagem de Pangasius hypophthalmus (Sauvage, 1878) criado em sistema raceway
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2020-02-04
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Universidade Federal de Goiás
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The adjustment of stocking density for fish with potential for fish farming, characterizes the
beginning of technological package development activities, which can help in the creation of
new species. The objective of this study was to evaluate the effect of stocking density on the
productive and physiological parameters of the Pangasius hypophthalmus during the
production period. 700 fish with initial weight of 527.91 ± 73, 40g were distributed in a
completely randomized design, consisting of five treatments and four replications. The fish
were housed in 20 polyethylene boxes with a volume of 500 liters of water, which
corresponded to the five treatments of 30, 50, 70, 90 and 110 fish/m3
, representing 15, 25,
35, 45 and 55 fish per experimental unit. Feeding was performed twice a day, seven days a
week, with commercial feed extruded to omnivorous, containing 32% of crude protein (CP)
and granulometry of 4 to 6 mm. The experimental period lasted 90 days. The Growth
performance was evaluated by the variables of body weight gain, feed intake, feed conversion
ratio and survival rate. The temperature, dissolved oxygen, pH, nitrite, total and non-ionized
ammonia were the limnological variables evaluated. As for carcass yields and biometric index,
fillet yield, eviscerated fish yield, head proportion, hepatosomatic index and visceral fat index,
weight of the block of viscera, relative weight of the intestine and relation body
length/intestine length. Blood biochemistry was evaluated through the concentrations of
glucose, chloride, lactate, total protein, total cholesterol, triglycerides, HDL, LDL and VLDL.
Complete cell blood count was performed. The data were subjected to analysis of variance,
test of comparison between means and application of regression models to the significance
level of P< 0.05. Statistical analyses were performed using the computational program R. Feed
conversion ratio and survival rate were not influenced by the rearing density. It was observed
quadratic effect of stocking densitiy on fish final weight (FW) and linear effect on body weight
gain (BWG), feed intake (FI), final biomass (FB) and biomass gain (BG). The limnological
variables of temperature (T °C), hydrogenionic potential (pH) and dissolved oxygen (DO) were
not affected by the stocking density, unlike nitrite (NO2-) levels, total ammonia (NH4+ + NH3
)
and non-ionized ammonia (NH3
), which presented Increasing linear effect by influence of
stocking density. The weight of the no edible compounds increased as the stocking density
increased. The carcass yield, serum biochemical profile and hematology were not influenced
by stocking density. It is concluded that for the cultivation of P. Hypophthalmus in intensive
system and tropical climatic conditions, stocking densities above 87 fish/m3
, provides better
fish development in the fating period of 90 days.
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RODRIGUES, Juliano Silva. Densidade de estocagem de Pangasius hypophthalmus (Sauvage, 1878) criado em sistema raceway. 2020. 87 f. Dissertação (Mestrado em Zootecnia) - Universidade Federal de Goiás, Goiânia, 2020.