The intestinal microbiota play an important role in the maintenance of the fish health. In this study, 150 Oreochromis niloticus were divided into five groups (G1–G5) and were subjected to alternate weekly exchange of feeding rate and frequency (3, 3, 1.5, 1.5 and 0%) and (2, 1, 2, 1 and 0 time), respectively, for 8 weeks. Enumeration of total intestinal bacteria revealed that the abundance of Lactobacillus was negatively correlated with those of Aeromonas, Pseudomonas and Edwardsiella. The abundance and proportion of Lactobacillus were affected by the change in feeding frequency. When fish were infected with Aeromonas hydrophila, survival rate significantly decreased in G5 (starved fish) compared with G1 (control group). The pro‐inflammatory cytokines, interleukin (IL)‐1β and tumour necrosis factor‐α, and anti‐inflammatory cytokine IL‐10 as well as serum antibacterial activity and respiratory burst activity were positively correlated with the proportion of Lactobacillus. The alternate weekly exchange of feeding regime did not alter the parametric morphology of the intestine, height and width of intestinal villi, number of goblet cells and width of muscle layer, except in G5. In conclusion, the alternate weekly exchange of feeding regime to starvation (G5), decrease in the feeding frequency to 1 time/day (G3) and decrease in feeding rate to 1.5% (G4) suppressed the immune status of fish, which became vulnerable to bacterial infection. Immune suppression was positively correlated with a decreased proportion of Lactobacillus spp.

中文翻译：

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每周交替的喂食方式会影响尼罗罗非鱼尼罗罗非鱼肠道菌群的多样性和免疫状态

肠道菌群在维持鱼类健康中起着重要作用。在这项研究中，将150个尼罗罗非鱼（Oreochromis niloticus）分为五组（G1–G5），并每周交替交换喂食速度和频率（3、3、1.5、1.5和0％）和（2、1、2、1和0次），分别为8周。肠道细菌总数的计数显示乳酸菌的丰度与气单胞菌，假单胞菌和爱德华菌的含量呈负相关。乳杆菌的丰度和比例受饲喂频率变化的影响。当鱼类感染了嗜水气单胞菌，相比于G1（对照组），G5（饥饿的鱼）的存活率显着降低。促炎细胞因子，白介素（IL）-1β和肿瘤坏死因子-α，抗炎细胞因子IL-10以及血清抗菌活性和呼吸爆发活性与乳酸杆菌的比例呈正相关。除了在G5中，每周一次的交替喂养方式没有改变肠道的参数形态，肠道绒毛的高度和宽度，杯状细胞的数量和肌肉层的宽度。总之，每周交替换食一次饥饿（G5），减少进食频率至每天1次（G3），减少进食率至1.5％（G4），抑制了鱼类的免疫状态，使鱼类变得脆弱细菌感染。免疫抑制与乳酸杆菌属的比例降低呈正相关。