Amar E C, Apines-Amar M J S, Faisan J P
Southeast Asian Fisheries Development Center, Aquaculture Department, Tigbauan, Iloilo, 5021, Philippines.
Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, Miagao, Iloilo, 5023, Philippines.
J Aquat Anim Health. 2018 Mar;30(1):39-49. doi: 10.1002/aah.10005.
Onion Allium cepa and ginger Zingiber officinale have health-promoting properties that qualify them as functional foods. The effect of repeated acute stressors was examined in juvenile Brown-marbled Grouper Epinephelus fuscoguttatus that were fed four diets supplemented with onion at 1.8%, ginger at 1.8%, vitamin C at 0.86%, and β-glucan at 0.8% of the diet. The non-supplemented diet served as the control. After 12 weeks of feeding, fish were exposed to stressors and were experimentally infected with a fish pathogen, the bacterium Vibrio harveyi JML1. After repeated exposure to hypoxia, cortisol levels rose significantly in the non-supplemented fish compared to those fed onion, ginger, β-glucan, or vitamin C. Within groups, postexposure cortisol levels in the onion-, ginger-, and vitamin C-fed fish did not change relative to pre-stress levels, whereas significant increases in poststress values were observed in the control and β-glucan groups. The net cortisol increase was also significantly greater in the non-supplemented group compared to the supplemented groups. The net cortisol increase did not vary among the supplemented groups except that the β-glucan-fed group exhibited a higher net increase than the onion-fed group. Similarly, repeated acute exposure to osmotic stress significantly increased the plasma cortisol level in the non-supplemented group compared to groups that received supplements; no differences were found in the supplemented groups except the β-glucan group. Within groups, significant increases in poststress values relative to pre-stress levels were found only in the control and β-glucan groups. Repeated acute exposure to hypoxia significantly increased cumulative mortality in the control group compared to the supplemented groups (except the β-glucan group), whereas repeated exposure to acute osmotic stress significantly increased cumulative mortality only in the control group 10 d after infection with V. harveyi JML1. Based on our collective results, most of the supplemented groups performed better than the control, but the best supplements were onion and ginger in terms of enhancing stress tolerance and increasing survival of Brown-marbled Grouper upon infection with V. harveyi JML1.
洋葱（Allium cepa）和姜（Zingiber officinale）具有促进健康的特性，使其有资格成为功能性食品。研究人员对幼年棕点石斑鱼（Epinephelus fuscoguttatus）进行了实验，这些鱼被喂食四种不同的饲料，分别添加了1.8%的洋葱、1.8%的姜、0.86%的维生素C和0.8%的β-葡聚糖，未添加任何成分的饲料作为对照。喂食12周后，让鱼暴露于应激源，并通过实验感染鱼类病原体哈维氏弧菌（Vibrio harveyi）JML1。与喂食洋葱、姜、β-葡聚糖或维生素C的鱼相比，反复暴露于低氧环境后，未添加任何成分的鱼体内皮质醇水平显著升高。在各实验组中，喂食洋葱、姜和维生素C的鱼在暴露后皮质醇水平相对于应激前水平没有变化，而对照组和β-葡聚糖组的应激后皮质醇水平显著升高。未添加任何成分的组皮质醇净增加量也显著高于添加组。除了喂食β-葡聚糖的组比喂食洋葱的组皮质醇净增加量更高外，添加组之间的皮质醇净增加量没有差异。同样，与接受添加物的组相比，反复急性暴露于渗透应激下，未添加任何成分的组血浆皮质醇水平显著升高；除了β-葡聚糖组外，添加组之间没有差异。在各实验组中，仅在对照组和β-葡聚糖组中发现应激后水平相对于应激前水平有显著升高。反复急性暴露于低氧环境显著增加了对照组的累积死亡率，与添加组（除β-葡聚糖组外）相比；而反复暴露于急性渗透应激下，仅在感染哈维氏弧菌JML-1 10天后的对照组中显著增加了累积死亡率。基于我们的综合结果，大多数添加组的表现优于对照组，但就增强应激耐受性和提高棕点石斑鱼感染哈维氏弧菌JML1后的存活率而言，最佳添加物是洋葱和姜。
