Department of Fish Health and Management, Central Laboratory for Aquaculture Research, Abbassa, Abo-Hammad, Sharqia, 44662, Egypt.
Department of Fish Biology and Ecology, Central Laboratory for Aquaculture Research, Abbassa, Abo-Hammad, Sharqia, 44662, Egypt.
Fish Physiol Biochem. 2019 Dec;45(6):1907-1917. doi: 10.1007/s10695-019-00685-8. Epub 2019 Jul 26.
A feeding trial was conducted to assess the effect of inclusion of dried powder of purslane, Portulaca oleracea, leaves in diets on growth, antioxidant, and immunological responses of Nile tilapia, Oreochromis niloticus, as well as its resistance to pathogenic bacteria, Aeromonas hydrophila. Fresh leaves of purslane were collected, dried, and mixed thoroughly with a basal fish diet at levels of 0.0 (control), 1.0, 2.0, and 3%. Fish (18.2 ± 0.4 g) fed one of the experimental diets up to apparent satiation twice a day for 7 weeks. At the end of the feeding trial, fish were intraperitoneally injected with pathogenic bacteria, A. hydrophila, and fish mortalities were observed and recorded up to 10 days post-challenge. Fish growth, weight gain, and specific growth rate were retarded significantly with increasing purslane levels in fish diets as compared to the control group. On the other hand, significant (P < 0.05) increases in plasmatic superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities accompanied with significant decreases in malondialdehyde (MDA) were observed with increasing purslane levels in fish diets. The respiratory burst (RB) activity and lysozyme value were significantly enhanced, while nitrous oxide (NO) decreased significantly with increasing purslane levels in fish diets over those of the control fish. After 10 days of the bacterial infection, no significant changes of MDA and SOD levels were observed, whereas CAT and GPX activities were significantly elevated. Additionally, RB and lysozyme activities were lower, while NO levels were elevated more than those before bacterial infection. Fish survival before and after bacterial infection was significantly affected by dietary purslane supplements, bacterial infection, and their interaction where dietary purslane improved the fish resistance to A. hydrophila infection in a dose-dependent manner. Purslane-fed fish showed highest relative percent of survival especially at an inclusion level of 3% (81.25%), whereas the control fish group showed lowest relative percent of survival (0.0%).
进行了一项饲养试验，以评估在饮食中添加马齿苋（Portulaca oleracea）干粉对尼罗罗非鱼（Oreochromis niloticus）生长、抗氧化和免疫反应的影响，以及其对致病性细菌嗜水气单胞菌（Aeromonas hydrophila）的抵抗力。采集新鲜的马齿苋叶，干燥并与基础鱼饲料充分混合，水平分别为 0.0（对照）、1.0、2.0 和 3%。鱼（18.2±0.4 g）每天两次摄食实验饲料，直至饱食，为期 7 周。在饲养试验结束时，鱼被腹腔内注射致病性细菌嗜水气单胞菌，观察并记录鱼的死亡率，直至攻毒后 10 天。与对照组相比，随着饲料中马齿苋水平的增加，鱼的生长、体重增加和特定生长率显著降低。另一方面，随着饲料中马齿苋水平的增加，血浆中超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和谷胱甘肽过氧化物酶（GPX）的活性显著增加（P<0.05），而丙二醛（MDA）的含量显著降低。随着饲料中马齿苋水平的增加，呼吸爆发（RB）活性和溶菌酶值显著增强，而一氧化氮（NO）显著降低。在细菌感染 10 天后，与对照组相比，MDA 和 SOD 水平没有显著变化，而 CAT 和 GPX 活性显著升高。此外，RB 和溶菌酶活性降低，而 NO 水平升高。在细菌感染前后，鱼的存活率受到饮食中马齿苋补充、细菌感染及其相互作用的显著影响，其中饮食中的马齿苋以剂量依赖的方式提高了鱼对嗜水气单胞菌感染的抵抗力。在 3%（81.25%）的添加水平下，马齿苋喂养的鱼表现出最高的相对存活率，而对照组的鱼表现出最低的相对存活率（0.0%）。
