College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China.
Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, 611130, China.
Fish Physiol Biochem. 2020 Oct;46(5):1759-1774. doi: 10.1007/s10695-020-00826-4. Epub 2020 Jul 11.
The study investigated the effects of dietary isoleucine (Ile) on skin mucus barrier and epithelial physical barrier functions of hybrid bagrid catfish Pelteobagrus vachelli × Leiocassis longirostris. A total of 630 fish (33.11 ± 0.09 g) were fed semi-purified isonitrogenous diets containing 5.0 (control), 7.5, 10.0, 12.5, 15.0, 17.5, and 20.0 g Ile kg diet for 8 weeks. The results indicated that dietary Ile increased (P < 0.05) in skin (1) mucus protein content and antimicrobial activity against three gram-negative bacteria (Aeromonas hydrophila, Escherichia coli, and Yersinia ruckeri) and two gram-positive bacteria (Streptococcus agalactiae and Staphylococcus aureus), (2) mucus lysofew information is available about the influencezyme (LZM), acid phosphatase (ACP), and alkaline phosphatase (AKP) activities, and complement 3 and 4 (C3 and C4) and immunoglobulin M (IgM) contents, (3) intelectin 1 (intl1), intelectin 2 (intl2), c-type-lysozyme (c-LZM), g-type-lysozyme (g-LZM), and β-defensin mRNA levels. Dietary Ile decreased (P < 0.05) reactive oxygen species (ROS), malondialdehyde (MDA), and protein carbonyl (PC) contents, and up-regulated (P < 0.05) CuZnSOD, GST, GPX1a, muc5ac, muc5b, zonula occludens-1 (ZO-1), zonula occludens-2 (ZO-2), occludin, and claudin 3 mRNA levels in skin. These results indicated that Ile improved skin mucus barrier function via increasing mucus protein, C3 and C4, and IgM contents and antibacterial factors activities, and promoted epithelial physical barrier function via decreasing skin antioxidant damage and improving tight junction structure in hybrid bagrid catfish.
该研究调查了饮食异亮氨酸（Ile）对杂交鱯鱼 Pelteobagrus vachelli × Leiocassis longirostris 皮肤黏液屏障和上皮物理屏障功能的影响。总共 630 条鱼（33.11±0.09 g）被喂食含有 5.0（对照）、7.5、10.0、12.5、15.0、17.5 和 20.0 g Ile kg 饮食的半纯化等氮饮食 8 周。结果表明，饮食 Ile 增加了（P<0.05）：（1）皮肤黏液蛋白含量和对三种革兰氏阴性菌（嗜水气单胞菌、大肠杆菌和鲁氏耶尔森菌）和两种革兰氏阳性菌（无乳链球菌和金黄色葡萄球菌）的抗菌活性；（2）黏液溶菌酶（LZM）、酸性磷酸酶（ACP）和碱性磷酸酶（AKP）活性以及补体 3 和 4（C3 和 C4）和免疫球蛋白 M（IgM）含量；（3）凝集素 1（intl1）、凝集素 2（intl2）、c 型溶菌酶（c-LZM）、g 型溶菌酶（g-LZM）和 β-防御素 mRNA 水平。饮食 Ile 降低了（P<0.05）活性氧（ROS）、丙二醛（MDA）和蛋白质羰基（PC）含量，并上调了（P<0.05）CuZnSOD、GST、GPX1a、muc5ac、muc5b、闭合蛋白-1（ZO-1）、闭合蛋白-2（ZO-2）、闭合蛋白和 Claudin 3 mRNA 水平皮肤。这些结果表明，Ile 通过增加黏液蛋白、C3 和 C4 以及抗菌因子的活性来改善皮肤黏液屏障功能，并通过降低皮肤抗氧化损伤和改善紧密连接结构来促进上皮物理屏障功能在杂交鱯鱼中。
