This study was designed to explore the dietary effects of Capsicum annuum oleoresin (CAO) on growth, body composition, sensory characteristics, gut microbiome, and intestinal histomorphometry of rainbow trout. Fish (195.13 ± 1.55 g) were fed diets with various CAO levels (0.0-Control, 7.0- g kg ⁻¹ C7, 14.0 g kg ⁻¹ -C14, 21.0 g kg ⁻¹-C21, and 28.0 g kg ⁻¹-C28) for a 30-day period. Results revealed that the maximum growth was achieved in C7 and C14 groups. Nevertheless, the growth parameters were similar in other groups compared to the control. Moreover, there were significant increases in dry matter and crude lipid contents in all CAO groups compared with the controls. The mean abundances (%) of the prevalent bacteria at the genus level in the intestinal trout samples presented no significant changes among the test groups. Dietary CAO significantly changed the intestinal histological structure, and was manifested by an increased number of goblet cells in the CAO-supplied groups. However, there were intestinal villus epithelial deformations associated with increasing dietary CAO, and were most prominent in the C28 group. The sensory attributes of cooked trout fillets showed that capsicum's pungent odor and taste was evident in the C14 group and subsequently increased with increasing dietary CAO levels. Accordingly, the results showed, for the first time, that dietary CAO at levels (7–14 g kg⁻¹) can enhance the growth of rainbow trout without negative effects on the sensory characters and gut health.

中文翻译：

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辣椒油树脂作为膳食类胡萝卜素对虹鳟生长、肠道微生物组、肠道组织形态学和感官特征的影响

本研究旨在探讨辣椒油树脂（CAO）的饮食对虹鳟鱼生长、身体成分、感官特征、肠道微生物组和肠道组织形态测量的影响。鱼（195.13 ± 1.55 g）饲喂含有不同 CAO 水平的饲料（0.0-对照、7.0- g kg ^-1 C7、14.0 g kg ^-1 -C14、21.0 g kg ^-1 -C21 和 28.0 g kg ^-1 - C28) 为期 30 天。结果显示，C7 和 C14 组实现了最大生长。然而，与对照组相比，其他组的生长参数相似。此外，与对照组相比，所有CAO组的干物质和粗脂质含量均显着增加。鳟鱼肠道样本中属水平普遍细菌的平均丰度（%）在测试组之间没有显着变化。膳食CAO显着改变了肠道组织学结构，表现为提供CAO的组中杯状细胞数量增加。然而，肠绒毛上皮变形与饮食中CAO的增加相关，并且在C28组中最为突出。煮熟的鳟鱼片的感官特性表明，辣椒的辛辣气味和味道在 C14 组中很明显，并且随后随着膳食 CAO 水平的增加而增加。因此，结果首次表明，膳食中CAO水平（7-14 g kg ^-1）可以促进虹鳟鱼的生长，而不会对感官特性和肠道健康产生负面影响。