Plant mucilages, like seed mucilage, as a polysaccharide have a wide range of beneficial properties such as anti stress, anti bacterial, growth and immunity enhancing properties. In this study was quince seed mucilage in juvenile rainbow trout ) Oncorhynchus mykiss ). Experimental treatments included control to evaluate the cellular, histological and microbial effects of the use of treatments (no grain mucilage), 1%, 3%, 6% and 9% mulch treatment.. In order to evaluate the intestinal histological characteristics, intestinal microbial system (SOD, CAT, GPX, Nrf2), fish sampling flora, EPC cell viability and expression of genes related to the antioxidant properties related to the control, 1 and 3% of mucilage and their best state was performed at the thirty day and the end of the trial (day 60). Based on the results, the lowest values ??of tissue was observed in 9% of mucilage. The highest villi length and diameter of the observed (P 0.05) in 1% mucilage treatment in 60 days, so that on day 60 no muscle layer were significantly (P 0.05) related to 9% mucilage group in 60 days. Also, the highest villi diameter was significant difference was observed between any of the treatments. The results of intestinal and 9%) not only did not have cytotoxicity, but also could lead to greater cell microbial culture showed that using mucilage for 30 days increased the intestinal microbial flora, but at the end of day 60, the intestinal microbial between any of the treatments (P 0.05). Based on MTT assay on EPC cell flora was reduced, so that on day 60 no significant difference was observed line, it was found that the use of high percentages of quince seed mucilage (6 highest level of gene expression was observed in control treatment and 3% viability. In the study of antioxidant gene expression, significantly lower SOD gene expression was observed in 9% highest CAT gene expression was significantly observed in 9% mucilage treatment mucilage treatment (P 0.05). The (P 0.05) and the lowest significant expression was observed in 6% mucilage mucilage (P 0.05). Also, relation to GPX gene, the highest level of gene treatment (P 0.05). Regarding the expression of Nrf gene, the used as a natural and balancing compound for intestinal microbial flora, expression was observed in 3% mucilage treatment and the lowest level was significantly in 9% treatment (P 0.05). The results of this study show that diets containing quince seed mucilage improve the tissue and microbial status of the intestines of fingerling rainbow trout and also reduced the expression improves histological properties, increases cell viability and reduces of antioxidant genes in liver tissue. Therefore, quince seed mucilage can be oxidative stress in juvenile rainbow trout.