日粮蛋白质供给对猪肉品质和肠道生理的作用及其机制

发布时间：2018-03-16 01:04

本文选题：日粮蛋白质供给　切入点：肉品质　出处：《中国农业大学》2017年博士论文　论文类型：学位论文

【摘要】：本论文旨在研究日粮蛋白质供给对猪肉品质、氮排放、血液循环游离氨基酸池以及肠道生理功能的作用及机制。试验一研究在必需氨基酸(Essential amino acid,EAA)和代谢能平衡的基础上,日粮粗蛋白质(Crude protein,CP)水平和来源对猪生长性能、氮排放和肉品质的影响。试验选取72头初始体重为89.5 ±0.9 kg的母猪,按照随机区组设计原则分为四组,设计2×2析因试验,饲喂不同CP水平(12%vs.14%)和来源(豆粕vs.棉粕)的日粮,试验期28 d。试验结果表明,降低日粮CP水平对猪日增重和蛋白质沉积没有显著影响(P0.10),但显著降低猪的氮摄入量、氮排放量、血清尿素氮含量和背最长肌pH45min,显著提高背最长肌的游离赖氨酸、蛋氨酸和总游离氨基酸含量以及氮效率(P0.05);棉粕代替豆粕有提高日增重的趋势(P = 0.08),且显著提高采食量、氮摄入量以及背最长肌的游离缬氨酸含量,显著降低背最长肌的总苯丙氨酸、色氨酸、酪氨酸和半胱氨酸含量(P0.05)。试验二分为两个动物试验,研究在EAA和代谢能平衡基础上,降低日粮CP水平(即蛋白质限饲)对猪小肠氨基酸吸收和血液循环游离氨基酸池的影响。动物试验Ⅰ选择72头初始体重为29.9 ± 1.5 kg的母猪,按照随机区组设计原则分为三组,分别饲喂CP水平为18%、16%和14%的日粮,饲喂28 d,检测全肠道表观消化率和空肠黏膜氨基酸转运载体蛋白表达。动物试验Ⅱ选择12头初始体重为22.7 ±1.3 kg的去势公猪,按照随机区组设计原则分为两组,安装多重血插管,分别饲喂动物试验Ⅰ中的18%和14%CP日粮,手术前后分别饲喂7 d,检测氨基酸和指示剂浓度,并计算血液循环游离氨基酸池和门静脉游离氨基酸流通速率/流通量。试验结果表明,蛋白质限饲显著降低胰脏指数(P0.05),在全肠道表观消化率方面,赖氨酸、蛋氨酸和缬氨酸随着日粮蛋白质水平降低而线性升高(P0.05),精氨酸、谷氨酸、天冬氨酸、甘氨酸、丝氨酸和酪氨酸则线性降低(P0.05)。蛋白质限饲缩小血液循环中除赖氨酸和苏氨酸外的所有游离氨基酸池(P0.05),显著降低门静脉的大部分游离氨基酸流通速率(P0.05)。蛋白质限饲显著上调小肽转运载体表达,但抑制中性和碱性氨基酸转运载体表达(P0.05)。试验三研究在日粮EAA和净能平衡基础上蛋白质限饲对猪肠道生理功能的作用及其机制。试验选用16头初始体重为13.5 ±0.5 kg的去势公猪,按照随机区组设计原则分为两组,分别饲喂CP水平为18%和14%的饲粮,饲喂28 d,分析空肠黏膜蛋白质组和mTOR信号通路。试验结果表明,蛋白质限饲显著降低猪蛋白质摄入量、日增重和空肠绒毛长度,改善饲料转化效率(P0.05)。在空肠黏膜中总共鉴定到5,275种可定量的蛋白质,其中包括202种差异表达蛋白(变化倍数2.0)。蛋白质限饲增强猪小肠黏膜蛋白质/碳水化合物消化、紧密连接结构和细胞粘附蛋白表达以及机体对外源性抗原的反应过程;抑制氨基酸跨膜转运、先天免疫和自身免疫以及细胞增殖与凋亡。蛋白质限饲通过抑制mTOR信号通路下调氨基酸转运与细胞增殖。综上,蛋白质供给通过改变猪的肌肉氨基酸组成改变肉品质,降低日粮蛋白质水平有利于减少氮排放;蛋白质限饲抑制猪肠道氨基酸吸收、缩小血液循环游离氨基酸池和降低门静脉游离氨基酸流通速率与流通量;蛋白质限饲对猪小肠黏膜氨基酸消化吸收、免疫功能、细胞更新和基因表达调控产生全方位的影响。猪小肠黏膜mTOR信号通路通过感应氨基酸供给对小肠生理功能起中枢调节作用。
[Abstract]:This paper aims to study the dietary protein supply on pork quality, nitrogen emission, the effect and mechanism of blood circulation of free amino acid pool and intestinal physiological function. Experimental study in essential amino acids (Essential amino, acid, EAA) based on the energy balance and metabolism, dietary crude protein (Crude, protein, CP) level and sources on the growth performance of pigs, effects of nitrogen emissions and meat quality. The experiment selects 72 head initial weight was 89.5 + 0.9 kg sows, according to randomized block design principles are divided into four groups, 2 * 2 factorial design, with different level of CP (12%vs.14%) and sources (soybean meal vs. cottonseed meal diet) 28, test results of D. test showed that the decrease of dietary CP levels on pig weight gain and protein deposition had no significant effect (P0.10), but significantly reduced the nitrogen intake of pigs, nitrogen emissions, serum urea nitrogen content and longissimus muscle pH45min, significantly improve the longissimus muscle Free lysine, methionine and total free amino acid content and the nitrogen use efficiency (P0.05); cottonseed meal instead of soybean meal increased ADG trend (P = 0.08), and significantly increased feed intake, nitrogen intake and free valine content of longissimus muscle, significantly reduce the total phenylalanine of longissimus muscle, tryptophan acid, tyrosine and cysteine content (P0.05). The test is divided into two two animal experiment study in EAA and metabolic energy balance on the basis of reducing dietary CP levels (i.e. protein restriction) effect on porcine intestinal absorption of amino acids and free amino acid pool of blood circulation. Animal test of 72 head initial body weight 29.9 + 1.5 kg sows, according to a randomized block design and divided into three groups and were fed the CP level of 18%, 16% and 14% of the diet, feeding 28 d, the apparent digestibility and jejunal mucosal amino acid transporter protein expression. The animal experiment of whole gut 12 head initial weight was 22.7 + 1.3 kg castrated boars, according to random block design principles are divided into two groups, install multiple blood intubation, were fed animal test of 18% and 14%CP diets were fed 7 d before and after surgery, detection of amino acids and concentration of indicator, and calculate the blood circulation and free amino acid pool portal vein / circulation flow rate of free amino acid. The results showed that protein restriction significantly reduced pancreas index (P0.05), in terms of total tract apparent digestibility, lysine, methionine and valine as the dietary protein level decreased linearly increased (P0.05), arginine, glutamic acid, aspartic acid, glycine, serine and tyrosine are decreased (P0.05). Protein restriction reduced all the free amino acid pool in lysine and threonine outside the blood circulation (P0.05), significantly reduce the circulation of most free amino acids of portal vein. Rate (P0.05). Protein restriction increased the peptide transporter expression, but inhibited alkaline and neutral amino acid transporter expression (P0.05). Experiment three studied in diet EAA and net energy balance based on the effect of feeding on protein limit of pig intestinal physiological function and its mechanism. 16 test head initial body weight of 13.5 + 0.5 kg castrated boars selected according to randomized block design principles are divided into two groups, were fed CP for 18% and 14% of the level of diet, feeding 28 d, analysis of jejunal mucosa proteome and mTOR signaling pathway. The results showed that protein restriction was significantly lower in pig protein intake, weight gain and villus length, improve feed conversion efficiency (P0.05). In the jejunum mucosa were identified to 5275 protein quantitative protein expression, 202 kinds of differences (including changes in multiples of 2). Protein restriction enhanced porcine intestinal mucosa protein / carbohydrate Complex digestion, tight junction and cell adhesion protein expression and the reaction process of exogenous antigen; inhibition of amino acid transport across the membrane, innate immunity and immune response, cell proliferation and apoptosis. Protein restriction reduced amino acid transport and cell proliferation by inhibiting the mTOR signaling pathway. Therefore, protein supply by changing the amino acids in the muscle of pigs the changes in the composition of meat quality, reduce the level of dietary protein helps to reduce nitrogen emissions; protein restriction inhibits pig intestinal absorption of amino acids, reduce the blood circulation of free amino acid pool and reduce portal vein circulation and circulation rate of free amino acids; protein restriction on porcine intestinal amino acid digestion and absorption, immune function, cell renewal and gene expression effect of regulation and control. To generate a full range of porcine intestinal mucosa mTOR pathway through the induction of amino acid supply on physiological function in small intestine The pivot of regulation.

【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S828.5

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