| In this study,Xiangdong black goats were selected as the study object,and goats were fed with different levels of ramie instead of alfafa(A,B,C,and D substitution ratios were 0%,35%,75%,and 100%,respectively).The goat’s growth performance,digestion and metabolism,and rumen fermentation metabolic index were measured to obtain the appropriate range of replacement ratio of ramie in the diet.On this basis,the gastrointestinal tissues of goats were obtained,and the mRNA expressions and protein expression of Bcl-2,Bcl-xl,Bax,and p53 in the endogenous pathways were analyzed by RT-PCR and Western Blotting.The expression analysis was performed to obtain the effects of different levels of ramie on mRNA expression and protein expression of apoptosis-related genes in gastrointestinal tissue cells,providing technical support for the regulation and application of ruminant nutrition.At the apparent level,there was no significant difference in the initial body weight and the body weight at the end of the experiment at different ramie levels(P>0.05).There was no significant difference in weight gain and daily weight gain between groups A,B,and C(P>0.05),but weight gain and daily gain in group D were significantly lower than those in the other three groups(P<0.0001).The intake of NDF in group D was significantly lower than that in group A and B(P<0.05);the intake of P in group D was significantly higher than that of group A(P<0.05);The fecal excretion of the Ash index in the C and D groups was significantly higher than that in the A group(P<0.05).The fecal excretion of the Ca index in the B,C,and D groups was significantly higher than that in the A group(P<0.05).CP digestibility in group C and D was significantly lower than that in group A(P<0.05);NDF digestibility in group D was significantly lower than that in group A(P<0.05);digestibility of ADF,Ash,and Ca in groups B,C,and D Significantly lower than A group(P<0.05);P digestibility of D group was significantly higher than A group(P<0.05).Different ramie treatment had no significant effect on the intake of DM,Energy,CP,ADF,Ash,and Ca(P>0.05);different ramie treatments had no significant effect on fecal excretion of DM,Energy,CP,NDF and P indicators(P>0.05);Different ramie treatment had no significant effect on digestibility of DM and Energy(P>0.05).At mRNA level of gene expression,in the rumen,mRNA expression of Bcl-xl was significantly up-regulated in group D compared with group A(P=0.004),and mRNA expression of Bax was significantly up-regulated in group D compared to the other three groups(P=0.0007);Compared with group C,the ratio of Bcl-2/Bax in group D was significantly down-regulated(P=0.02);the mRNA expression levels of Bcl-2 and p53 at different levels of ramie treatment were not significantly different(P>0.05).In the jejunum,the mRNA expression of p53 was significantly up-regulated in group D compared with group A and B(P=0.01),and the expression of Bcl-2 mRNA was down-regulated in group D compared with group C(P=0.07);compared with group B,the ratio of Bcl-2/Bax in C and D groups was down-regulated(P=0.06);the mRNA expression levels of Bcl-xl and Bax at different levels of ramie treatment were not significantly different(P>0.05).In the ileum,the mRNA expression of Bcl-2,p53,Bcl-xl,Bax and Bcl-2/Bax were not significantly different in different ramie treatment groups(P>0.05).There was no significant effect of Caspase-3 activity in rumen,jejunum and ileum at different levels of ramie treatment(P>0.05).At the protein level of gene expression,in the rumen,protein expression of Bcl-xl was significantly down-regulated in group D compared with group B and C(P=0.03);protein expression of Bax in group D was significantly down-regulated compared to the other three groups(P = 0.002).In the jejunum,compared with group A and group C,protein expression of p53 in group B was significantly up-regulated(P=0.001);the expression of Bcl-2protein in each group of ramie treatment groups had no significant difference(P>0.05).In summary,the following conclusions are drawn: 1)The proportion of ramie substitutes alfafa should not exceed 35%;2)At the mRNA level of gene expression,100% ramie level may induce apoptosis in the rumen and jejunum,different levels of ramie treatment may have no effect on ileum tissue apoptosis;3)The apoptotic pathway of gastrointestinal tract of goats at different levels of ramie may be achieved by AIF(apoptosis inducing factor)rather thant by the caspase pathway;4)At the protein level of gene expression,100% ramie level may affect the apoptotic in the rumen tissue,and 35% ramie level may affect the apoptosis of jejunum tissue. |
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