EFFECTS OF DIETARY MULBERRY LEAF EXTRACT AND 1-DEOXYNOJIRIMYCIN ON GROWTH, DIGESTION AND IMMUNITY CAPACITY, AND INTESTINAL MICROORGANISM OF CHINESE GIANT SALAMANDER (ANDRIAS DAVIDIANUS)

This study explored the effects of feeding basal diet, mulberry leaf extract diet (containing 0.75% MLE) and 1-deoxynojirimycin diet (containing 0.04‰ DNJ) on growth, digestion and immunity capacity, and intestinal microorganism in giant salamanders for a 90-day trail. Giant salamanders with an initial body weight of (47.81±0.23) g were randomly divided into 3 groups for these 3 diets. Compared with the control diet, the weight gain rate and feed efficiency in MLE and DNJ groups were significantly improved (P<0.05); lipase and trypsin activities were also significantly increased (P<0.05). The contents of endotoxin in plasma acid and malondialdehyde in intestine in MLE and DNJ groups were significantly lower than those in control group (P<0.05). Compared with control group, the number of intestinal villi in MLE and DNJ groups were increased, and the tight junction between intestinal mucosa cells in MLE and DNJ groups were closer. Compared with the control group, the mRNA expression levels of target of rapamycin (TOR), interleukin-10 (IL-10), polymeric immunoglobulin receptor (pIgR), toll-like receptor-2 (TLR2) and myeloid differentiation primary response gene88 (MyD88) in MLE group were significantly increased (P<0.05), and the mRNA expression level of pIgR in the DNJ group was significantly increased (P<0.05). The diversity of intestinal bacteria in MLE and DNJ group was higher than that in control group. There was no significant difference in weight gain rate and feed efficiency among 3 groups (P>0.05); MLE group significantly increased the activities of pepsin, H⁺-K⁺-ATPase, Na⁺-K⁺-ATPase and the total intestinal antioxidant capacity compared with the control group (P<0.05). In addition, MLE group had closer tight junction between intestinal mucosa cells, higher intestinal villi height (P<0.05), and lower plasma endotoxin content (P<0.05), compared with DNJ group. In summary, MLE and DNJ can improve growth performance, digestion and absorption functions, intestinal antioxidant and immune capabilities, promote the growth of beneficial bacteria in the intestine, increase the diversity of intestinal microorganisms, and promote the intestinal development of the giant salamander. Combined the structure and function of the stomach and intestines, MLE is more effective than DNJ.