本文選題：必需氨基酸缺乏 + 纈氨酸��； 參考：《華中農(nóng)業(yè)大學(xué)》2017年碩士論文

【摘要】：斷奶仔豬階段,以玉米-豆粕型為基礎(chǔ)的日糧中,Val是繼Lys、Met、Thr、Trp后又一限制性氨基酸。研究還發(fā)現(xiàn),Val缺乏能造成更為顯著的采食量和體重下降,但Val缺乏引起采食量下降的機(jī)制目前還不清楚。因此,研究Val缺乏對動物采食量的調(diào)控機(jī)制有著重要意義。采食量按照調(diào)控部位分為外周調(diào)控和中樞調(diào)控。外周調(diào)控中胃腸激素是調(diào)控動物采食量的主要方式。最新的研究表明,肝臟分泌的FGF21也參與到營養(yǎng)物質(zhì)的攝入調(diào)控。中樞系統(tǒng)中下丘腦是重要的調(diào)控部位,一方面,下丘腦通過調(diào)節(jié)食欲肽(NPY/Agrp)和厭食欲肽(POMC/CART)的表達(dá)調(diào)控采食量。另外,下丘腦mTOR、AMPK信號通路也發(fā)揮著重要作用。中樞前梨狀皮層還能感應(yīng)必需氨基酸缺乏,激活GCN2通路抑制采食。本試驗(yàn)通過行為學(xué)分析、檢測外周和中樞食欲相關(guān)基因、蛋白表達(dá)和信號通路活性,以及血液中氨基酸變化,闡明Val缺乏對動物采食量的調(diào)控機(jī)制。主要內(nèi)容及結(jié)果如下:1.日糧新奇性測試:為了排除日糧類型的影響,選擇12只體重相近的雄性昆明小鼠,飼喂普通日糧5天后,隨機(jī)分配到Val缺乏組和對照組中,記錄第6、7天采食量。試驗(yàn)結(jié)果顯示,與對照組和更換日糧前的采食量相比,Val缺乏組小鼠的采食量極顯著降低(P0.01)。第6天分段累計(jì)采食量表明,在第1小時Val缺乏組采食量顯著低于對照組(P0.05),表明小鼠能夠快速感應(yīng)和拒絕Val缺乏的日糧。2.Val缺乏對短期采食量和攝食行為的影響:將16只野生和14只FGF21雜合雄性小鼠隨機(jī)分配到對照組和Val缺乏組中,禁食24小時后,觀察小鼠的攝食行為,并分段記錄各階段采食量。結(jié)果顯示進(jìn)食Val缺乏的野生小鼠第2小時采食量顯著低于對照組(P0.05),FGF21雜合小鼠則延長到第12小時。無論是野生型小鼠,還是FGF21雜合小鼠,Val缺乏對禁食后第一次攝食行為影響均不顯著。餐模式結(jié)果表明,Val缺乏顯著降低了(P0.05)每餐采食量、每餐采食量以及全天和夜間每餐進(jìn)食時間。Val缺乏顯著降低(P0.05)全天和夜間攝食時間和進(jìn)食間隔。與野生型小鼠相比,FGF21雜合小鼠顯著降低了(P0.05)全天進(jìn)食次數(shù),但FGF21雜合小鼠顯著增加了(P0.05)平均每餐攝食時間。3.Val缺乏對小鼠長期采食量的影響:攝食行為試驗(yàn)結(jié)束后,接著飼喂4周,記錄每天采食量變化,每兩天稱一次體重。試驗(yàn)結(jié)果表明,Val缺乏顯著降低了小鼠(P0.05)每周以及全期平均日采食量、體重和屠宰性能。4.對比試驗(yàn):選擇8只體重相近的雄性野生昆明小鼠,前10天飼喂Val缺乏日糧,后10天飼喂對照日糧。結(jié)果發(fā)現(xiàn),在進(jìn)食Val缺乏階段顯著降低小鼠的采食量(P0.05),并逐漸降低體重。當(dāng)進(jìn)食對照日糧后,小鼠的采食量和體重分別在第1天和第2天恢復(fù)到正常水平。5.Val缺乏對小鼠外周胃腸激素及肝臟FGF21表達(dá)的影響:盡管Val缺乏對小腸GLP-1、PYY、Ghrelin mRNA水平無顯著差異,但Val缺乏顯著增加了(P0.05)小腸中CCK mRNA水平。相反的是,Val缺乏極顯著地降低胃中l(wèi)eptin mRNA水平(P0.01)。無論是野生小鼠還是FGF21雜合小鼠,Val缺乏組都顯著增加了(P0.05)肝臟FGF21、ATF4的mRNA表達(dá)水平、p-eIFα水平以及血液中FGF21濃度。重要的是,肝臟FGF21表達(dá)水平與采食量之間有一定的線性(R2=0.515,P=0.0003)和二次回歸關(guān)系(R2=0.60,P=0.0003),并且血液中FGF21與采食量之間存在負(fù)相關(guān)(R=-0.502,P=0.0047)。6.Val缺乏對血液中氨基酸模式的影響:無論是野生小鼠還是FGF21雜合小鼠中,Val缺乏顯著降低了(P0.05)小鼠血液中游離Val、Met濃度,極顯著提高了(P0.01)His濃度。血液中Val濃度與采食量有良好的線性(R2=0.79,P0.0001)和二次回歸關(guān)系(R2=0.794,P0.0001)。相似的是血液中Val濃度與肝臟中FGF21mRNA表達(dá)水平也有一定的線性(R2=0.56,P0.0001)和二次回歸關(guān)系(R2=0.615,P=0.0002)。血液Val濃度還與血液中FGF21濃度呈極顯著的負(fù)相關(guān)(R=-0.47,P=0.008)。另外,血液中His濃度與采食量同樣具有一定的線性關(guān)系(R2=0.58,P0.0001)。7.Val缺乏對中樞食欲肽NPY和信號通路活性的影響:Val缺乏對下丘腦NPY陽性細(xì)胞率無顯著影響(P0.05),相似的是Val缺乏對下丘腦弓狀核中p-mTOR陽性細(xì)胞數(shù)也無顯著影響(P0.05),但顯著地增加(P0.05)前梨狀皮層中p-eIF2α陽性細(xì)胞數(shù)。綜上所述,小鼠能夠快速感應(yīng)日糧中Val缺乏,并改變攝食行為。主要通過減少進(jìn)食時間和每餐采食量降低小鼠短期采食量。Val長期缺乏時,促進(jìn)了小腸CCK的表達(dá),增加了血液中His濃度,降低了血液中Val濃度并刺激肝臟FGF21的表達(dá),同時增加中樞前梨狀皮層p-eIF2α陽性細(xì)胞數(shù)量,抑制了小鼠長期的采食量,并減輕體重。
[Abstract]:In the weaned piglet stage, Val is another limiting amino acid following Lys, Met, Thr and Trp in the diet based on the corn soybean meal type. It is also found that Val deficiency can cause more significant feed intake and weight loss, but the mechanism of Val deficiency causing the decrease of feed intake is unclear. Therefore, the regulation machine for Val deficiency on animal feed intake is studied. Food intake is of great significance. The intake of food is divided into peripheral control and central control according to the regulatory parts. Gastrointestinal hormones are the main ways to regulate animal feed intake in peripheral control. The latest research shows that the FGF21 secreted by the liver is also involved in the regulation of nutrient intake. The central nervous system is an important regulatory part of the lower thalamus, on the one hand, the lower colliculus. The brain regulates the intake of food by regulating the expression of orexin (NPY/Agrp) and anorexin (POMC/CART). In addition, the mTOR, AMPK signaling pathway in the hypothalamus also plays an important role. The central pyriform cortex can also induce essential amino acid deficiency and activate the GCN2 pathway to inhibit eating. This test was conducted by behavioral analysis to detect the peripheral and central appetite related groups. Due to protein expression, signaling pathway activity and changes in amino acids in the blood, the regulation mechanism of Val deficiency on animal feed intake was clarified. The main contents and results were as follows: 1. diet novelty test: to exclude the influence of diet type, 12 male Kunming mice with similar weight were selected and randomly assigned to Val deficiency for 5 days. In the group and the control group, the feed intake was recorded on day 6,7. The test results showed that the intake of mice in the Val deficiency group was significantly lower than the control group and the food intake before the replacement of the diet (P0.01). The cumulative feed intake of the sixth day subsection showed that the intake of the Val deficiency group was significantly lower than the control group (P0.05) in the first hour period, indicating that the mice could be quickly induced and refused. The effect of Val deficiency.2.Val deficiency on short-term feed intake and feeding behavior: 16 wild and 14 FGF21 heterozygous male mice were randomly assigned to the control group and the Val deficiency group. After 24 hours of fasting, the feeding behavior of the mice was observed and the feed intake at each stage was recorded in segments. The fruit showed that the wild mice fed with Val deficiency were collected for second hours. The food intake was significantly lower than that of the control group (P0.05), and the FGF21 heterozygous mice were prolonged to twelfth hours. Both the wild and FGF21 heterozygous mice, the Val deficiency had no significant influence on the first feeding behavior after the fasting. The meal pattern showed that Val deficiency significantly reduced the intake of (P0.05) per meal, food intake per meal, and every meal at night and night. Feeding time.Val was not significantly reduced (P0.05) all day and night feeding time and feeding interval. Compared with wild type mice, FGF21 heterozygous mice significantly decreased (P0.05) eating times of all days, but FGF21 heterozygous mice significantly increased (P0.05) the average feeding time of.3.Val deficiency on the long-term intake of mice: feeding behavior test After 4 weeks, the daily feed intake was recorded for 4 weeks and the weight was recorded every two days. The results showed that the Val deficiency significantly reduced the daily and full average daily feed intake, weight and slaughter performance of the mice (P0.05): 8 similar male wild Kunming mice were selected, the first 10 days were fed with Val diet, and 10 days later. It was found that the feed intake (P0.05) of mice was reduced significantly and the weight was gradually reduced at the stage of Val deficiency. After eating control diet, the intake and weight of mice recovered to the normal level in first days and second days, respectively, to the normal level of.5.Val deficiency on the expression of gastric intestinal hormone and liver FGF21 in mice, although Val deficiency was lacking. There was no significant difference in GLP-1, PYY, and Ghrelin mRNA levels in the small intestine, but Val deficiency significantly increased the level of CCK mRNA in the small intestine. On the contrary, Val deficiency significantly reduced leptin mRNA in the stomach (P0.01). The level of p-eIF alpha and the concentration of FGF21 in the blood. It is important that there is a certain linear (R2=0.515, P=0.0003) and two regression relationship between the FGF21 expression level and the intake of the liver (R2=0.60, P=0.0003), and there is a negative correlation between the FGF21 and the feed intake in the blood (R=-0.502, P=0.0047).6.Val on the amino acid patterns in the blood: no matter the effect on the pattern of amino acids in the blood: In the wild mice or in the FGF21 heterozygous mice, Val deficiency significantly reduced the free Val and Met concentration in the blood of (P0.05) mice and significantly increased the concentration of (P0.01) His. There was a good linear (R2=0.79, P0.0001) and two regression relationship between the concentration of Val and the feed intake in the blood (R2= 0.794, P0.0001). The expression level also has a certain linear (R2=0.56, P0.0001) and two regression relations (R2=0.615, P=0.0002). The concentration of Val in blood also has a very significant negative correlation with the concentration of FGF21 in the blood (R=-0.47, P=0.008). In addition, the concentration of His in the blood and the intake of the blood have a certain linear relationship (R2=0.58, P0.0001).7.Val lacks the central appetite peptide. The effect of signal pathway activity: Val deficiency had no significant effect on the rate of NPY positive cells in the hypothalamus (P0.05). Similar was that Val deficiency had no significant influence on the number of p-mTOR positive cells in the hypothalamic arcuate nucleus (P0.05), but significantly increased the number of p-eIF2 alpha positive cells in the anterior pyriform cortex (P0.05). In summary, the mice could quickly induce Val in the diet. The lack of food intake and change of feeding behavior, mainly by reducing the feeding time and food intake per meal to reduce the short-term intake of.Val in mice, promote the expression of CCK in the small intestine, increase the concentration of His in the blood, reduce the concentration of Val in the blood and stimulate the expression of FGF21 in the liver, and increase the number of p-eIF2 alpha positive cells in the central pyriform cortex. The long-term intake of the mice was inhibited and weight loss was reduced.

【學(xué)位授予單位】：華中農(nóng)業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：S816

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

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本文編號：1897149