Rearing density is recognized as a critical consideration in fish husbandry: whereas higher densities may increase productivity and reduce production costs, they also represent a potential source of chronic stress and may negatively affect growth performance and product quality. Accordingly, we investigated the effects of rearing density on growth, physiological responses, and flesh quality of cobia (Rachycentron canadum). Fish (46.32 ± 0.22 g, mean ± SEM) were reared for 42 days in a low salinity (17.6 g/L) recirculation system according to treatments designated as low density (5 fish/tank, 3.30 ± 0.02 kg/m³), medium density (10 fish/tank, 6.67 ± 0.03 kg/m³), or high density (20 fish/tank, 13.15 ± 0.16 kg/m³). Weight gain and specific growth rate were significantly higher among fish reared at low density; however, feed intake, feed conversion ratio, hepatosomatic index, condition factor, and dress‐out were equivalent among treatments. Plasma cortisol, lactate, and osmolality levels were not affected by rearing density, and values were within basal ranges reported for juvenile cobia. Fillet drip‐loss did not vary among treatments, but rigor mortis developed more rapidly among fish reared at high density. Rearing juvenile cobia at high densities may reduce growth performance and may influence the timing of rigor development.

中文翻译：

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饲养密度对少年军曹鱼（Rachycentron canadum）生长，生理反应和肉质的影响

饲养密度被认为是鱼类饲养中的关键考虑因素：较高的密度可能会提高生产率并降低生产成本，但它们也可能成为长期压力的潜在来源，并可能对生长性能和产品质量产生负面影响。因此，我们调查了饲养密度对军曹鱼（Rachycentron canadum）的生长，生理反应和肉质的影响。根据低密度处理（5条鱼/罐，3.30±0.02 kg / m ³），在低盐度（17.6 g / L）再循环系统中将鱼（46.32±0.22 g，平均值±  SEM）饲养42天，中密度（10条鱼/坦克，6.67±0.03 kg / m ³）或高密度（20条鱼/坦克，13.15±0.16 kg / m ³）。在低密度饲养的鱼中，体重增加和比生长速率显着更高；然而，不同处理之间的采食量，饲料转化率，肝体指数，条件因子和换药率是相同的。血浆皮质醇，乳酸和重量摩尔渗透压浓度不受饲养密度的影响，其值在报道的少年军曹鱼的基本范围内。圆角滴水损失在不同处理方法之间没有差异，但是在高密度饲养的鱼类中，死角的发展更快。以高密度饲养少年军曹鱼可能会降低生长性能，并可能影响严格发育的时机。