Evaluation Of The Antioxidant Effect Of Yak Whey Powder In Vivo

The discharge of large quantities of yak whey causes environmental pollution and waste of resources.The rational exploitation and use of yak whey resources is an urgent issue for herders and dairy processors.Existing studies have shown that the supplementation of protein and other nutrients in whey can improve antioxidant indexes,morphological indexes,inflammatory immunity,intestinal flora and faecal volatile composition in vivo.The antioxidant properties and effects on intestinal flora structure of bovine whey powder,donkey whey powder and sheep whey powder have been demonstrated,but it is not clear what the antioxidant properties and effects on intestinal flora structure of yak whey powder are.In this paper,the antioxidant effects of yak whey protein supplementation were investigated in aging mice by combining in vivo antioxidant parameters(SOD,MDA),morphological parameters(body weight,thymus index),high-throughput sequencing of intestinal flora structure and abundance and electronic nasal monitoring of mouse metabolite odour information.(1)In this paper,we first explored the effect of yak whey protein supplemented diet on oxidative stress using a D-galactose-induced senescence model to monitor body weight,thymic index,SOD and MDA.The results were as follows: SOD activity in the OLD group was significantly lower than in the NC,VC,YL and YH groups(P < 0.01).MDA levels were significantly higher in the OLD group(P < 0.01);while feeding VC,YL and YH caused a significant decrease in MDA levels(P < 0.01),which was not different from the NC group.The results of weight growth rate showed a significant decrease(P < 0.01)in the group of mice in the OLD group,and a significant increase(P < 0.01)in weight growth rate after the intervention of NC,VC,YL and YH in aging mice.The results of thymus index showed a significant decrease in the OLD group(P< 0.01)and no significant difference between the NC and intervention groups(VC,YL,YH).Yak whey powder could improve the antioxidant capacity of D-galactose-induced senescent mice,slow down the degree of oxidative stress damage,increase body weight and delay thymus atrophy.(2)The effect of yak whey powder on the intestinal flora of aging mice was investigated by high-throughput sequencing of the intestinal flora structure and abundance,and the results showed that yak whey powder significantly increased the abundance and diversity of intestinal flora in the OLD group.Gavage of yak whey powder significantly increased the relative abundance of Lactobacillus spp.and decreased the relative abundance of Prochlorococcus spp.and Helicobacter spp.The relative abundance of Lactobacillus spp.showed a significant positive correlation with thymus ratio and SOD,but a significant negative correlation with MDA.The relative levels of Helicobacter spp.were significantly and positively correlated with MDA.No significant correlation was found between other genera and antioxidant indexes.Yak whey powder can alter the intestinal micro-ecological structure and quantity of aging organisms,increase the relative levels of Lactobacillus and decrease the relative levels of Helicobacter,affecting oxidative stress and inflammatory aging in humans,thus delaying aging.(3)The odour information of the faeces of mice in different treatment groups was detected by using electronic nose,and the results showed that there were significant differences in the odour of the faeces of mice in different intervention groups.The fecal odour of the YH group was the closest to that of the NC control group.A combination of PCA and CDA analyses was used to qualitatively distinguish between yak whey powder and control mice and to differentiate between the aging and intervention groups and between the high and low dose groups of yak whey powder.The results of the correlation analysis with the top 10 dominant genera in terms of antioxidant index and relative abundance in the intestine,monitored by electronic nose,showed that thymus index,SOD and body weight growth rate were significantly positively correlated with sensors W1 C,W3C,W5 C and W3 S,and negatively correlated with sensors W5 S,W1S,W1 W and W2 W,while the opposite was true for the oxidative index MDA.The prediction models of mouse thymus index,SOD,MDA and body weight growth rate were established using multiple linear regression models with R2 values above 0.4802,and the odour information was strongly correlated with the physiological and biochemical indicators of mice.It is feasible to evaluate the in vivo activity of whey powder non-invasively based on the sensor response of volatile metabolites in faeces.Yak whey powder can be applied to functional foods to improve the structure and abundance of intestinal flora to influence oxidative stress and delay ageing.This thesis may provide some theoretical basis for the recycling of yak whey powder and provide theoretical support for future evaluation of in vivo indicators based on odour information.