Ma Shifeng, Liang Xiaofang, Chen Pei, Wang Jie, Gu Xu, Qin Yuchang, Blecker Christophe, Xue Min
National Aquafeed Safety Assessment Center, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Food Science and Formulation, University of Liège, Gembloux Agro-Bio Tech, Avenue de la Faculté d' Agronomie, 2B, B-5030, Gembloux, Belgium.
Anim Nutr. 2022 Apr 21;10:99-110. doi: 10.1016/j.aninu.2022.04.005. eCollection 2022 Sep.
protein (CAP) is a new single-cell protein source originating from inactivated bacteria. An in vitro digestion experiment and an 8-wk growth experiment were conducted to evaluate the molecular weight distribution of the CAP hydrolysate, and the effects of dietary CAP levels on the growth performance, plasma parameters, hepatic and intestinal health, and the diversity of gut-adherent microbiota of largemouth bass (). The fish (initial body weight of 47.99 ± 0.01 g) were fed diets where CAP gradually replaced 0% (CAP0), 12.5% (CAP12.5), 25% (CAP25), 37.5% (CAP37.5) and 50% (CAP50) of low-temperature steam dried anchovy fish meal (LTFM) in the diet. Results showed that the content of peptides below 1,000 Da in the CAP hydrolysate (0.56 mg/mL) was higher than that of the LTFM hydrolysate (0.48 mg/mL). Dietary CAP inclusion had no negative effect on growth performance, while whole-body lipid content significantly reduced in the CAP25 and CAP50 groups ( < 0.05). The plasma alanine aminotransferase activities and triglyceride concentrations in the CAP inclusion groups were significantly lower than those in the CAP0 group ( < 0.05). The plasma aspartate aminotransferase activity was significantly reduced in the CAP37.5 group ( < 0.05). The richness and diversity of the gut-adhesive microbiota and the proportion of in the CAP50 group were significantly higher than those in the CAP0 group ( < 0.05). Dietary CAP inclusion inhibited inflammatory responses by down-regulating the mRNA levels of interleukin 1β (), and transforming growth factor β1 ( < 0.05) in the liver. The mRNA levels of acetyl-CoA carboxylase 1 were significantly down-regulated in the CAP12.5, CAP25 and CAP37.5 groups ( < 0.05), while that of fatty acid synthase was significantly down-regulated in the CAP50 group ( < 0.05). These results demonstrate that dietary CAP inclusion could improve the hepatic and intestinal health of largemouth bass, and can be helpful to further develop CAP as a functional feed ingredient.
蛋白（CAP）是一种源自灭活细菌的新型单细胞蛋白源。进行了体外消化实验和为期8周的生长实验，以评估CAP水解产物的分子量分布，以及日粮中CAP水平对大口黑鲈生长性能、血浆参数、肝脏和肠道健康以及肠道附着微生物群多样性的影响。将初始体重为47.99±0.01克的鱼投喂日粮，其中CAP逐渐替代日粮中0%（CAP0）、12.5%（CAP12.5）、25%（CAP25）、37.5%（CAP37.5）和50%（CAP50）的低温蒸汽干燥凤尾鱼粉（LTFM）。结果表明，CAP水解产物（0.56毫克/毫升）中低于1000道尔顿的肽含量高于LTFM水解产物（0.48毫克/毫升）。日粮中添加CAP对生长性能没有负面影响，而CAP25和CAP50组的鱼体脂肪含量显著降低（P<0.05）。CAP添加组的血浆丙氨酸氨基转移酶活性和甘油三酯浓度显著低于CAP0组（P<0.05）。CAP37.5组的血浆天冬氨酸氨基转移酶活性显著降低（P<0.05）。CAP50组肠道附着微生物群的丰富度和多样性以及拟杆菌属的比例显著高于CAP0组（P<0.05）。日粮中添加CAP通过下调肝脏中白细胞介素1β（IL-1β）、肿瘤坏死因子α（TNF-α）和转化生长因子β1（TGF-β1）的mRNA水平来抑制炎症反应（P<0.05）。CAP12.5、CAP25和CAP37.5组中乙酰辅酶A羧化酶1的mRNA水平显著下调（P<0.05），而CAP50组中脂肪酸合酶的mRNA水平显著下调（P<0.05）。这些结果表明，日粮中添加CAP可以改善大口黑鲈的肝脏和肠道健康，有助于进一步将CAP开发为功能性饲料成分。
