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草业学报 ›› 2017, Vol. 26 ›› Issue (11): 94-103.DOI: 10.11686/cyxb2017160

• 研究论文 • 上一篇    下一篇

高精料对泌乳奶山羊瘤胃上皮氧化应激和胆固醇代谢的影响

耿雅丽, 田平, 罗燕文, 华灿枫, 陶诗煜, 田靖, 倪迎冬*   

  1. 南京农业大学,农业部动物生理生化重点开放实验室,江苏 南京 210095
  • 收稿日期:2017-03-31 修回日期:2017-06-14 出版日期:2017-11-20 发布日期:2017-11-20
  • 通讯作者: *E-mail:niyingdong@njau.edu.cn
  • 作者简介:耿雅丽(1992-),女,河北衡水人,在读硕士。E-mail:2604413221@qq.com
  • 基金资助:
    国家重大基础研究发展计划 973 项目(No.2011CB100802)资助

Effects of feeding high concentrate diets to lactating dairy goats on oxidative stress and cholesterol metabolism in ruminal epithelium

GENG Ya-Li, TIAN Ping, LUO Yan-Wen, HUA Can-Feng, TAO Shi-Yu, TIAN Jing, NI Ying-Dong*   

  1. Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agriculture University, Nanjing 210095, China
  • Received:2017-03-31 Revised:2017-06-14 Online:2017-11-20 Published:2017-11-20

摘要: 为了研究长期或短期饲喂高精料日粮对泌乳期奶山羊瘤胃上皮组织氧化应激和胆固醇代谢的影响,实验选用17只健康的经产泌乳中期关中奶山羊,随机分为3组:饲喂低精料组(对照组,LC,n=5);长期饲喂高精料组(HL, n=7),19周饲喂期;短期饲喂高精料组(HS,n=5),4周饲喂期。实验结束后采集瘤胃组织,用PBS反复清洗,于液氮中速冻后置于-80 ℃冰箱保存。结果显示,与对照组相比,HL和HS组山羊瘤胃上皮组织中细胞周期相关基因CDK2和CDK4 mRNA表达水平显著升高(P<0.05),且HS组p-ERK1/2蛋白表达显著升高(P<0.05),但GPR41和GPR43蛋白表达无显著变化(P>0.05);HL和HS组山羊瘤胃上皮组织促细胞凋亡基因Casepase9 mRNA表达显著升高(P<0.05),HS组抗凋亡Bcl-2/Bax mRNA表达比例呈下降趋势(0.05<P<0.1);HS组瘤胃上皮组织中抗氧化酶CAT和总抗氧化能力T-AOC显著升高(P<0.05),HL组CAT含量和SOD酶活性显著升高(P<0.05),但总抗氧化能力T-AOC无显著差异(P>0.05);HS组瘤胃上皮组织中胆固醇含量下降达显著水平(P<0.05),且HL组呈下降趋势(0.05<P<0.1),胆固醇酰基转移酶ACAT1和ACAT2基因表达显著上调(P<0.05),HS组瘤胃上皮组织中胆固醇的含量与ACAT1和ACAT2 mRNA的表达呈显著的负强相关(P=0.0067, r=-0.8208;P=0.0100, r=-0.7980)。与对照组比较,HS和HL组瘤胃上皮组织中VFA转运相关基因AE2、DRANHE2、NHE3和νH+ ATPase mRNA表达显著升高(P<0.05),NHE2蛋白表达升高但未达显著差异水平(P>0.05)。与HL组相比,HS组山羊瘤胃上皮组织中总抗氧化能力T-AOC显著升高(P<0.05);且胆固醇含量显著下降(P<0.05)。以上结果说明,短期饲喂高精料日粮可加快泌乳期奶山羊瘤胃上皮组织的更新,提高组织总抗氧化能力;而长期饲喂高精料日粮未引起细胞增殖相关蛋白和总抗氧化能力的显著变化;饲喂高精料日粮可以加快瘤胃上皮组织对VFA的转运。此外,饲喂高精料日粮引起瘤胃上皮组织内胆固醇含量降低,胆固醇酰基转移酶基因表达的显著上调,提示其对瘤胃上皮组织更新的潜在影响。

Abstract: In order to investigate the effects of feeding high concentrate diets on the functional status of ruminal epithelia in terms of oxidative stress and cholesterol metabolism, seventeen lactating goats with similar body weight and milk production were randomly divided into three groups, including LC (n=5), HS (n=5) and HL (n=7) groups, which were fed by diets of concentrate∶forage of 35∶65 for whole experiment period (LC), concentrate∶forage of 65∶35 for 4 weeks (HS), and concentrate∶forage of 65∶35 for 19 weeks (HL), respectively. At the end of the experiment, ruminal epithelial tissues were sampled, promptly immersed in liquid nitrogen and then stored at -80 ℃ for analysis. The results showed that mRNA expression of the CDK2 and CDK4 genes related to cell cycle significantly increased in both HS and HL goats (P<0.05). The level of p-ERK1/2 proteins increased in HS but not in HL goats (P<0.05). However, GPR41 and 43 protein expression in the ruminal epithelium was not changed both in HS and HL compared to LC. The expression of the Casepase9 gene participating in cell apoptosis was significantly up-regulated in the HL and HS groups, while the anti-apoptotic index of the relative ratio of Bcl-2/Bax mRNA expression showed a tendency to decrease in the HS group compared to LC group (0.05<P< 0.1). In addition, the enzyme activity of SOD and CAT in the epithelium significantly increased in HL and HS goats compared to LC goats (P<0.05), whereas the total anti-oxidative capacity (T-AOC) increased only in HS goats (P<0.05). The level of cholesterol in ruminal epithelium significantly decreased in the HS group (P<0.01), and also showed a decreasing trend in the HL group (P=0.06). The enzymes ACAT1 and 2, which may be involved in the regulation of cholesterol metabolism, significantly increased in HL and HS goats compared to LC goats (P<0.05). Correlation analysis revealed that cholesterol concentration in the ruminal epithelium was negatively correlated with ACAT1 and ACAT2 mRNA expression in the HS group (P=0.0067, r=-0.8208; P=0.0100, r=-0.7980). Compared with the LC group, mRNA expressions of AE2, DRA, NHE2, NHE3 and νH+ ATPase genes involving VFAs transportation significantly increased (P<0.05), while NHE2 protein expression was not altered both in HS and HL groups. Compared with the HL group, the HS group’s T-AOC significantly increased (P<0.05) and the level of cholesterol significantly decreased (P<0.05). These results indicate that feeding high concentrate diets over a short time period can improve the health status and functions of ruminal epithelium, while feeding high concentrate diets over a longer period might lessen these beneficial effects.