ABSTRACT
INTRODUCTION: Pacu (Piaractus mesopotamicus) is a Brazilian fish species of high commercial value and has emerged as one of the main species with potential for intensive farming. This study aimed to investigate the impact of choline supplementation on productive performance, visceral fat, hepatosomatic indices, proximate composition, serum biochemical profile, and liver coloration in juvenile pacu (Piaractus mesopotamicus). METHOD: The 60-day experiment was conducted in the experimental hatchery of the Study Group of Aquaculture Management - GEMAq of the State University of West Paraná, Brazil. The completely randomized design consisted of five treatments with four replicates each. A total of 200 fish, with an average initial weight and length of 4.25 g and 5.97 cm, were distributed among 20 experimental hapas, resulting in a stocking density of 10 fish per experimental unit. Fish fed a choline-deficient diet exhibited the lowest values for final weight, weight gain, visceral fat, and hepatosomatic index. Conversely, in terms of proximate composition, fish fed choline-deficient diets had the highest moisture content but the lowest crude fat content. Triglyceride levels in juvenile pacu were significantly higher in groups fed diets containing choline (400 to 1200 mg kg-1 ). We also observed significant differences in the cyan color of the liver (P < 0.05). Notably, we observed significant differences in the cyan coloration of the liver (P < 0.05). Other parameters did not exhibit significant changes in response to varying choline levels in the diets. RESULT: Our study demonstrated that choline supplementation in P. mesopotamicus juveniles at an optimal concentration of 400 mg kg-1 significantly impacted growth, metabolism, productive performance, proximate composition, biochemical parameters, and liver color. CONCLUSION: These findings offer crucial guidance for aquaculture professionals, enabling them to enhance growth and health in P. mesopotamicus farming. Further research on choline's influence on lipid metabolism holds potential for more precise dietary recommendations, ultimately improving the efficiency and sustainability of aquaculture practices for this species.
ABSTRACT
This study is aimed at assessing the feeding frequency for tilapia fingerlings. 240 fishes were randomly distributed in 24 containers. The feeding consisted of six frequencies: 4 (F4), 5 (F5), 6 (F6), 7 (F7), 8 (F8), and 9 (F9) times a day. The weight gain was significantly higher in F5 and F6 when compared to F4 (p = 0.0409 and 0.0306, respectively). Feed intake and apparent feed conversion did not differ between treatments (p = 0.129 and p = 0.451). About water quality, the nitrogen levels in the water from the treatments differed between F4 and F5 (p = 0.0478) and F4 and F6 (p = 0.0283) and for P between F4 and F6 (p = 0.0215) and F4 and F9 (p = 0.0432). The x 2 test showed a dependence relationship between feed frequencies and the muscle fibers frequency (p < 22 × 10-17), prevailing fibers between 10-20 micrometers in F4, F5, F6, and F7 and 30-40 in F8 and F9. The area of the hepatocytes differed only between F5 and F9, while the nucleus area did not. Partial net revenue differed in 10% between F5 and F4 (p = 0.0812) and between F6 and F4 (p = 0.0568). In conclusion, fingerlings fed 5 to 6 times a day have better zootechnical and partial recipes.
ABSTRACT
ABSTRACT: The present research aimed to investigate the stabil¬¬ity of pellets and phosphorus leaching of diets formulated for juveniles of Nile tilapia (Oreochromis niloticus), with different sources of phosphorus and different exposure times in water. Six diets were elaborated by varying the source of phosphorus (1 ‒ dicalcium phosphate (DP); 2 ‒ meat and bone meal (MBM); 3 ‒ poultry meal (PM); 4 ‒ anchovy meal (AM); 5 ‒ tilapia filleting industrial meal (TM); 6 ‒ calcined bone meal (CBM)) and, then, were submitted to four exposure times in water (5, 10, 15 and 20 minutes), with three replicates. Thus, 72 aquariums of 30‒liters were used, each being an experimental unit. All diets were evaluated for electrical conductivity of water, turgidity of pellets, mineral matter leaching, flotation of pellets, and total phosphorus leaching. Only turgidity and flotation of pellets varied with the different sources of phosphorus in the diets. The MBM diet had the highest turgidity of pellets. The PM, AM, and CBM diets had the highest flotation of pellets. The total phosphorus leaching had a linear effect with the increase of the exposure time, showing a greater release of phosphorus in the water with increase of exposure time. Data showed that PM, AM, and CBM diets had less potential impact on the aquatic environment. Conversely, the TM diet has greater polluting potential. These results showed that diets formulated with different sources of phosphorus exhibit distinct actions in the water, providing different effects on the fish culture environment.
RESUMO: O presente trabalho tem como objetivo investigar a estabilidade de pellets e a lixiviação do fósforo na água proveniente de diferentes dietas formuladas para juvenis de tilápia do Nilo (Oreochromis niloticus), considerando distintas fontes de fósforo e diferentes tempos de exposição na água. Para tanto, foram elaboradas seis dietas com variação da fonte de fósforo (1: fosfato dicálcico (DP); 2: farelo de carne e ossos (MBM); 3: farelo de aves (PM); 4: farelo de anchova (AM); 5: farelo industrial de filetagem de tilápia (TM); 6: farelo de osso calcinado (CBM)), as quais foram submetidas a quatro tempos de exposição em água (5, 10, 15 e 20 minutos), com três repetições. Utilizaram-se 72 aquários de 30 litros, sendo cada um deles uma unidade experimental. A água dentro dos aquários foi mantida sob constante aeração e temperatura ao redor de 25 °C. Todas as dietas foram avaliadas quanto à condutividade elétrica da água, turgidez, lixiviação de matéria mineral, flotação de pellets e lixiviação total do fósforo. Apenas a turgidez e a flutuação dos pellets variaram com as diferentes fontes de fósforo nas dietas. A dieta MBM apresentou a maior turgidez de pellets. As dietas PM, AM e CBM apresentaram a maior flutuação de pellets. A lixiviação do fósforo total teve um efeito linear com o aumento do tempo de exposição, resultando em maior liberação de fósforo na água. A lixiviação de matéria mineral apresentou interação entre fontes de fósforo e tempos de exposição das dietas, com efeito linear para a dieta TM. As dietas PM, AM e CBM apresentam as menores concentrações de efluentes em relação a dieta TM. Esses resultados revelaram que dietas formuladas com diferentes fontes de fósforo apresentam ações distintas na água em relação ao potencial poluidor.
