Menezes Ludmila L C, Machado Vânia M, Souto Cristielle N, Proença Danilo C, Bueno Guilherme W, Guimarães Igo G
Laboratório de Pesquisa em Aquicultura, Universidade Federal de Jataí, Campus cidade universitária, Jataí, GO, Brazil.
Departamento de Reprodução Animal e Radiologia Veterinária da FMVZ-Universidade Estadual de Paulista, Botucatu, SP, Brazil.
J Anim Physiol Anim Nutr (Berl). 2025 Jul 17. doi: 10.1111/jpn.70005.
Phosphorus is essential for fish growth as it is crucial in skeletal development and metabolic reactions. The dietary requirement for this mineral varies among fish species and growth stages. Therefore, the objective of this study was to determine the available phosphorus (AP) requirement for tambaqui during the grow-out phase (± 400 to 1000 g) using growth parameters, whole-body macronutrient composition, whole-body, scales, and bone mineral content, biochemical blood parameters, and activity of antioxidant enzymes as response parameters. A total of 128 tambaqui (395 g ± 20) were distributed across 15 tanks (1000 L each) connected to a recirculating water system, following a completely randomized design with five dietary treatments (4.1, 5.8, 8.0, 9.1, and 10.3 g/kg of AP) and three replicates per treatment. The fish were fed with experimental diets to apparent satiation for 180 days. The apparent digestibility coefficients (ADC) of the experimental diets were also determined to report the requirement on an available nutrient basis. No mortality or apparent signs of P deficiency were observed during the growth trial. The ADC of the diets decreased with increasing total phosphorus levels. AP supplementation in the diet did not affect growth performance parameters except phosphorus utilization, which decreased linearly with increasing AP supplementation. Bone mineralization increased with dietary AP supplementation, while the scale and whole-body mineralization were unaffected. Dietary AP levels, except for serum phosphorus and triglycerides, significantly affected blood biochemical parameters. The highest superoxide dismutase (SOD) activity was observed in fish fed 8 g/kg AP in the diet. The estimated requirement for the highest serum immunoglobulin concentration was 6.17 g/kg of AP. Our findings suggest that tambaqui in the grow-out stage can develop adequately without inorganic phosphorus supplementation to plant-based diets; 4.1 g/kg AP (or 25.2 mg AP/kg BW/day) seems to be sufficient to maintain growth parameters. However, this minimal level is associated with increased adiposity. To maximize bone mineralization, 10.3 g/kg AP (or 63.5 mg AP/kg BW/day) is required. Intermediate dietary levels (around 6.17 g/kg AP or 37.9 mg AP/kg BW/day) were associated with higher total serum protein, lysozyme, and immunoglobulin concentrations, suggesting possible physiological benefits.
磷对鱼类生长至关重要，因为它在骨骼发育和代谢反应中起着关键作用。这种矿物质的日粮需求量因鱼类品种和生长阶段而异。因此，本研究的目的是利用生长参数、鱼体常量营养素组成、鱼体、鳞片和骨骼矿物质含量、血液生化参数以及抗氧化酶活性作为响应参数，确定坦巴基鱼在育成阶段（±400至1000克）的有效磷（AP）需求量。总共128尾坦巴基鱼（395克±20）被分配到15个水箱（每个水箱1000升）中，这些水箱连接到一个循环水系统，采用完全随机设计，有五种日粮处理（4.1、5.8、8.0、9.1和10.3克/千克AP），每个处理三个重复。给鱼投喂实验日粮至明显饱足，持续180天。还测定了实验日粮的表观消化率系数（ADC），以便以可利用营养素为基础报告需求量。在生长试验期间未观察到死亡或明显的磷缺乏迹象。日粮的ADC随总磷水平的增加而降低。日粮中添加AP除了磷利用率外，对生长性能参数没有影响，磷利用率随AP添加量的增加呈线性下降。随着日粮中AP添加量的增加，骨矿化增加，而鳞片和鱼体矿化不受影响。除血清磷和甘油三酯外，日粮AP水平显著影响血液生化参数。在日粮中添加8克/千克AP的鱼中观察到最高的超氧化物歧化酶（SOD）活性。血清免疫球蛋白浓度最高时的估计需求量为6.17克/千克AP。我们的研究结果表明，育成阶段的坦巴基鱼在不添加无机磷的植物性日粮中也能充分生长；4.1克/千克AP（或25.2毫克AP/千克体重/天）似乎足以维持生长参数。然而，这个最低水平与肥胖增加有关。为了使骨矿化最大化，需要10.3克/千克AP（或63.5毫克AP/千克体重/天）。中等日粮水平（约6.17克/千克AP或37.9毫克AP/千克体重/天）与较高的血清总蛋白、溶菌酶和免疫球蛋白浓度相关，表明可能具有生理益处。
