College of Animal Science and Technology, Sichuan Agricultural University, Wenjiang, Chengdu, Sichuan, China.
Chongqing Three Gorges Vocational College, Wanzhou, Chongqing, China.
J Appl Microbiol. 2019 Nov;127(5):1327-1338. doi: 10.1111/jam.14405. Epub 2019 Aug 2.
An 8-week trial was performed to evaluate the differences in the intestinal microbiota and immune function of common carp (Cyprinus carpio)-fed different diets.
The fish (initial weight 492·6 ± 30 g, n = 270) were randomly divided into three groups with three replicates and were fed earthworms (group A), earthworms + duckweed (group M) or duckweed (group P) respectively. The diversity and dominant microbiota of the intestinal bacteria were detected by denaturing gradient gel electrophoresis, and the abundance of dominant bacteria was quantified by qPCR. Additionally, the activities of some nonspecific immune enzymes and antioxidant enzymes were determined. The results showed that higher diversity and abundance of intestinal microbiota were observed in group M and group P (P < 0·05). Based on the intestinal microbiota, Cetobacterium was only detected in the intestines of common carp in group A, and Bacillus was identified in groups M and P. Additionally, a higher abundance of Bacteroidetes and Firmicutes was also found in the intestine in group P than in group A (P < 0·05). Interestingly, the higher activities of immune enzymes were detected in intestine of common carp in group M, such as acid phosphatase, phosphatase (AKP), lysozyme, total antioxidant capacity, superoxide dismutase, catalase, glutathione peroxidase. In addition, the lower level of metabolites were also detected, such as nitric oxide and malondialdehyde.
Our results indicate that the intestinal microbiota and intestinal immunity of common carp were affected by diet. Meanwhile, the results show that a mixed diet can promote and improve the immune function of the omnivorous carp intestine, which suggests that paddy fields might be more suitable for the intestinal health and animal welfare of omnivorous fishes because they contain plant and animal diets.
As an ecological aquaculture strategy, the rice-fish mode has attracted attention among farmers, researchers and even consumers, especially for the cultivation of common carp in paddy fields. In paddy fields, fish can eat plant- and animal-based diets. However, it is not clear whether common carp feeding on a mixed diet in paddy fields have better intestinal health. This experiment is one of only a few studies performed from the perspective of intestinal micro-organisms and immunity to successfully study the effects of different natural diets on adult common carp. This study also provides a theoretical basis for healthy breeding of common carp in paddy fields.
进行了为期 8 周的试验，以评估不同饮食喂养的鲤鱼肠道微生物群和免疫功能的差异。
将（初始体重 492.6±30g，n=270）鱼随机分为三组，每组三个重复，分别投喂蚯蚓（A 组）、蚯蚓+浮萍（M 组）或浮萍（P 组）。通过变性梯度凝胶电泳检测肠道细菌的多样性和优势菌群，用 qPCR 定量优势菌群的丰度。此外，还测定了一些非特异性免疫酶和抗氧化酶的活性。结果表明，M 组和 P 组肠道微生物群的多样性和丰度更高（P<0.05）。基于肠道微生物群，仅在 A 组鲤鱼的肠道中检测到鲸杆菌，而在 M 组和 P 组中鉴定出芽孢杆菌。此外，P 组鲤鱼肠道中厚壁菌门和Firmicutes 的丰度也高于 A 组（P<0.05）。有趣的是，在 M 组中检测到更高的免疫酶活性，如酸性磷酸酶、碱性磷酸酶（AKP）、溶菌酶、总抗氧化能力、超氧化物歧化酶、过氧化氢酶、谷胱甘肽过氧化物酶。此外，还检测到较低水平的代谢物，如一氧化氮和丙二醛。
我们的结果表明，饮食会影响鲤鱼的肠道微生物群和肠道免疫功能。同时，结果表明，混合饮食可以促进和改善杂食性鲤鱼肠道的免疫功能，这表明稻田可能更适合杂食性鱼类的肠道健康和动物福利，因为它们含有植物和动物饮食。
作为一种生态水产养殖策略，稻鱼模式引起了农民、研究人员甚至消费者的关注，特别是对于稻田养殖鲤鱼。在稻田里，鱼可以吃植物性和动物性食物。然而，目前尚不清楚以混合饮食喂养的稻田鲤鱼是否具有更好的肠道健康。这项实验是为数不多的从肠道微生物和免疫的角度成功研究不同天然饮食对成年鲤鱼影响的实验之一。本研究也为稻田健康养殖鲤鱼提供了理论依据。
