Effects of dietary protein levels on intestinal tract histomorphology and microflora composition in juvenile pearl gentian grouper
MAI Haobin1， GUO Xinwei1， WANG Jingang1， CHI Shuyan 1,2* ，DONG Xiaohui 1,2,3， YANG Qihui 1,2， LIU Hongyu 1,2， ZHANG Shuang 1,2
1.Laboratory of Aquatic Animal Nutrition and Feed, Guangdong Ocean University; 2.Research Center for Accurate Nutrition and Highly Efficient Feed Engineering of Aquatic Animals of Guangdong Province; 3.Key Laboratory of Aquatic, Livestock and Poultry Feed Science and Technology in South China, Ministry of Agriculture and Rural Affairs
Abstract: Juvenile pearl gentian grouper (Epinephelus lanceolatu♂× E. fuscoguttatus♀) with body weight 6.50 g were reared in a 1 m3 tank and fed isonitrogen and isoenergetic diets containing protein levels of 35%(P35), 40%(P40), 45%(P45), 50%(P50), 55%(P55) and 60%(P60) at water temperature of 28-30 ℃ for 8 weeks to investigate the effect of the dietary protein level on intestinal tract hismorphology and microflora composition of hybrid grouper. It was found that there was significantly higher villus height in foregut and hindgut in group P50 than that in groups P40, P45 and P60 (P<0.05), and significantly lower villus width than that in groups P35 and P40 (P<0.05), with the minimal crypt depth in midgut and hindgut in group P50. The maximl muscle thickness was observed in group P50, without significant differences in the diversity indices of Shannon, Simpson, Coverage, and ACE (P>0.05), significantly higher Chao index only in groups P60 and P55 than that in groups P40, P45 and P50 (P<0.05). At the phylum level, the dominant colonies of each group were Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes, with the minimal Proteobacteria and the maximal Firmicutes in group P50. At the level of genus, Rhodococcus, Ralstonia, Acinetobacter and Pseudomonas were dominant species, with the maximal Lactobacillus, and lower Acinetobacter, Pseudomonas, and Syntrophobacter in group P50. It can be concluded that the diversity of intestinal flora was not affected significantly by dietary protein levels, while abundance of intestinal flora and intestinal histomorphology is involved in dietary protein levels in pearl gentian grouper, effectively improved intestinal histomorphology in pearl gentian grouper fed diet containing 50% of protein, which helps colonize beneficial bacteria such as Lactobacillus and reduces the content of pathogenic bacteria.
麦浩彬, 郭鑫伟, 王金港, 迟淑艳, 董晓慧, 杨奇慧, 刘泓宇, 章双. 摄食不同水平饲料蛋白质对珍珠龙胆石斑鱼幼鱼肠道组织形态和菌群组成的影响[J]. 大连海洋大学学报, 2020, 35(1): 63-70.
MAI Haobin, GUO Xinwei, WANG Jingang, CHI Shuyan, DONG Xiaohui, YANG Qihui, LIU Hongyu, ZHANG Shuang, . Effects of dietary protein levels on intestinal tract histomorphology and microflora composition in juvenile pearl gentian grouper. Journal of Dalian Ocean University, 2020, 35(1): 63-70.
2020, Vol. 35 
