Fish challenged with pathogens often show behavioral disorders. The present study investigated the influence of Aeromonas salmonicida infection on the body color changes of Atlantic salmon (Salmo salar L.). In both conditions of a white background and transfer from the black background to the white background, the body color contrast of the fish infected with A. salmonicida (100 μL bacterium solution 8.2 × 10⁹ CFU ml⁻¹ in the dorsal muscle) declined significantly following an initial increase compared with the control group (100 μL 0.9 % NaCl); the greatest differences were observed on day 11, at 57.6 % and 52.7 % respectively (P<0.01). In the black background (transferred from white to the black background), A. salmonicida infection resulted an initial lower and then higher contrast in the challenged fish (P<0.01), and the greatest difference occurred on day 5, reaching 156.7 % (P<0.01). Meanwhile, the cortisol, melanocyte stimulating hormone (MSH) and melanin-concentrating hormone (MCH) levels in serum were also evaluated. Comparing the infected fish with the control fish, the cortisol (7.2 % ∼ 21.2 %), MSH (25.8 % ∼48.6 %) and MCH (36.4 % ∼ 54.4 %) levels of the infected fish were elevated to varying degrees after infection with A. salmonicida (P < 0.05). The results suggested that A. salmonicida challenge altered the color-change behavior, which might be regulated by MSH and MCH.

受到病原体攻击的鱼通常表现出行为失常。本研究调查了沙门气单胞菌感染对大西洋鲑（Salmo salar L.）体色变化的影响。在白色背景和从黑色背景转移到白色背景的两种情况下，感染了鲑鱼曲霉（100μL细菌溶液，在背肌中的细菌浓度为8.2×10 ⁹ CFU ml ^-1）的鱼的体色对比度显着下降。与对照组相比（100μL0.9％NaCl）初始增加后；在第11天观察到最大差异，分别为57.6％和52.7％（P <0.01）。在黑色背景下（从白色背景转变为黑色背景），沙门氏菌感染在受攻击的鱼类中产生了先低后高的对比（P < 0.01），最大差异发生在第5天，达到156.7％（P < 0.01）。同时，还评估了血清中的皮质醇，黑素细胞刺激激素（MSH）和黑色素浓缩激素（MCH）水平。将感染鱼与对照鱼进行比较，A感染后，感染鱼的皮质醇（7.2％〜21.2％），MSH（25.8％〜48.6％）和MCH（36.4％〜54.4％）的水平有所不同。鲑鱼（P＜0.05）。结果表明，鲑鱼 挑战改变了变色行为，这可能受MSH和MCH调节。