Digestible protein requirements for maintenance, growth, and efficiency of protein utilization in pacu (Piaractus mesopotamicus) juveniles: an exponential nitrogen utilization model

• Published in: Latin american journal of aquatic research Vol. 49; no. 4; pp. 608 - 619
• Main Authors: Mansano, Cleber F.M, Silva, Edney P, Khan, Kifayat U, Macente, Beatrice I, Nascimento, Thiago M.T, Sakomura, Nilva K, Fernandes, Joao B.K, Takahashi, Leonardo S
• Format: Journal Article
• Language: English; Spanish
• Published: Valparaiso Pontificia Universidad Catolica de Valparaiso, Escuela de Ciencias del Mar 01-09-2021; Pontificia Universidad Catolica de Valparaiso; Pontificia Universidad Católica de Valparaíso. Facultad de Recursos Naturales. Escuela de Ciencias del Mar
• Subjects: Acclimation; Acclimatization; Body composition; Body weight; Diet; Efficiency; Experiments; Fish; FISHERIES; Juveniles; Maintenance; MARINE & FRESHWATER BIOLOGY; Nitrogen; NMR; Nuclear magnetic resonance; Nutrition; OCEANOGRAPHY; Piaractus mesopotamicus; Proteins; Retention; Satiety; Tanks; Utilization; Brazil; feed intake; monomolecular model; Piaractus mesopotamicus; pacu nutrition; maintenance requirement; nitrogen deposition
• ISSN: 0718-560X; 0718-560X
• DOI: 10.3856/vol49-issue4-fulltext-2678

The present study aimed to estimate digestible protein (DP) requirements for maintenance and growth and assess the efficiency of protein utilization in pacu (Piaractus mesopotamicus) juveniles. A complete randomized design consisted of seven treatments, and five replicates (tanks) per treatment was used. After a one-week acclimation period, 350 pacu juveniles of 27.48 [+ or -] 1.8 g (initial average body weight - BW) were equally distributed among 35 tanks (10 fish per tank) of 450 8. Fish were fed with seven graded digestible protein levels (64.5, 111.8, 164.6, 217.1, 264.4, 316.2 and 369.5 g [kg.sup.-1]) three times a day until apparent satiation for 120 days. The monomolecular model parameters including nitrogen maintenance requirement (NMR) (37.76 mg [BW.sup.0.67] [kg.sup.-1] [d.sup.-1]), daily nitrogen deposition (ND) (194.8 mg [BW.sup.0.67] [kg.sup.-1] [d.sup.-1]), and protein intakes (based on metabolic BW) of 1638, 1902, and 2241 mg [kg.sup.-1][BW.sup.0.67] [d.sup.-1] for 75, 80 and 85% maximum theoretical nitrogen retention ([NR.sub.max]T), respectively and the efficiency of protein utilization (529 X [10.sup.-6]) were estimated through the relationship between nitrogen intake (NI) and ND. The digestible protein requirements for 75, 80, and 85% of [NR.sub.max]T were estimated as 187, 217, and 256 g [kg.sup.-1] respectively by the monomolecular model based on the daily feed intake of 2% of live BW of pacu juveniles.