Department of Animal and Aquatic Sciences, Faculty of Agriculture, Chiang Mai University, Chiang Mai, 50200, Thailand; Science and Technology Research Institute, Chiang Mai University, 239 Huay Keaw Rd., Suthep, Muang, Chiang Mai, 50200, Thailand.
Department of Fisheries, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran.
Fish Shellfish Immunol. 2019 Oct;93:428-435. doi: 10.1016/j.fsi.2019.07.077. Epub 2019 Jul 27.
The present study aimed to assess the possible effects of Assam tea (Camellia sinensis) extract (ATE) on growth performances, immune responses, and disease resistance of Nile tilapia, Oreochromis niloticus against Streptococcus agalactiae. Five levels of ATE were supplemented into the based diet at 0, 1, 2, 4, and 8 g kg feed of Nile tilapia fingerlings (10.9 ± 0.04 g initial weight) in triplicate. After four and eight weeks of feeding, fish were sampled to determine the effects of the tea supplements upon their growth performance, as well as serum and mucosal immune responses. A disease challenge using S. agalactiae was conducted at the end of the feeding trial. Fish fed ATE revealed significantly improved serum lysozyme, peroxidase, alternative complement (ACH50), phagocytosis, and respiratory burst activities compared to the basal control fed fish (P < 0.05). The mucus lysozyme and peroxidase activities were ameliorated through ATE supplementation in the tilapia diets. Supplementation of ATE significantly (P < 0.05) enhanced final body weight, weight gain, and specific growth rate; while a decreased feed conversion ratio was revealed at 2 g kg inclusion level, after four and eight weeks. Challenge test showed that the relative percent survival (RSP) of fish in each treatment was 33.33%, 60.00%, 83.33%, 76.68%, and 66.68% in groups fed 0, 1, 2, 4, and 8 g kg, respectively. In summary, diets supplemented with ATE especially at 2 g kg increased the humoral and mucosal immunity, enhanced growth performance, and offered higher resistance against S. agalactiae infection in Nile tilapia.
本研究旨在评估阿萨姆茶（Camellia sinensis）提取物（ATE）对尼罗罗非鱼（Oreochromis niloticus）生长性能、免疫反应和对无乳链球菌（Streptococcus agalactiae）抵抗力的可能影响。将 5 个水平的 ATE 添加到基础饲料中，尼罗罗非鱼鱼苗（初始重量为 10.9±0.04g）的饲料中分别添加 0、1、2、4 和 8g/kg，每组重复 3 次。在喂养 4 周和 8 周后，取样鱼以确定茶补充剂对其生长性能以及血清和粘膜免疫反应的影响。在喂养试验结束时进行了无乳链球菌的疾病挑战。与基础对照组相比，喂食 ATE 的鱼的血清溶菌酶、过氧化物酶、替代补体（ACH50）、吞噬作用和呼吸爆发活性显著提高（P<0.05）。在罗非鱼饲料中添加 ATE 可改善粘液溶菌酶和过氧化物酶活性。ATE 补充剂显著提高了终体重、体重增加和特定生长率（P<0.05）；而在第 4 周和第 8 周，2g/kg 组的饲料转化率降低。挑战测试显示，每个处理组鱼的相对存活率（RSP）分别为 0、1、2、4 和 8g/kg 组的 33.33%、60.00%、83.33%、76.68%和 66.68%。总之，饲料中添加 ATE，特别是 2g/kg，可以提高罗非鱼的体液和粘膜免疫力，增强生长性能，并提供更高的无乳链球菌感染抵抗力。
