论文部分内容阅读
本试验旨在研究日粮蛋白水平对不同生理阶段猪胃肠道钙敏感受体(Calcium-sensing receptor,Ca SR)基因表达、血液胃肠激素分泌的影响,探讨蛋白水平与Ca SR基因表达和胃肠激素分泌的关系。选择健康、体重相近约10 kg(9.57±0.64)kg杜×长×大三元杂交断奶仔猪、35kg(36.47±0.20)kg生长猪和60 kg(62.30±0.07)kg肥育猪各18头,分阶段饲养,每阶段18头猪随机分为3组,每组6头,单栏饲养,以玉米-豆粕型日粮为基础,断奶仔猪日粮粗蛋白水平为20%、17%、14%,生长猪日粮粗蛋白水平为18%、15%、12%,肥育猪日粮粗蛋白水平为16%、13%、10%,饲养期分别为45、30、50 d,试验结束后屠宰,采集前腔静脉血液、小肠各部位组织,测定血液中胃肠激素水平、小肠各部位组织中Ca SR的表达。结果表明:当日粮蛋白水平降低后,不同阶段猪小肠Ca SR基因表达下调(P<0.05),断奶仔猪血清胆囊收缩素(CCK)、胰高血糖素样肽-1(GLP-1)和酪酪肽(PYY)浓度显著降低,生长猪血清CCK、葡萄糖促胰岛素肽(GIP)浓度也明显下降,而肥育猪只有血清GIP浓度显著降低(P<0.05);相关性分析表明,断奶仔猪空、回肠Ca SR表达与血中GLP-1和GIP显著正相关(P<0.05),回肠Ca SR表达与血中PYY存在显著正相关(P<0.05);生长猪十二指肠Ca SR表达与CCK显著正相关(P<0.05),而空、回肠Ca SR表达则与GIP显著正相关(P<0.05);肥育猪小肠各段Ca SR表达与胃肠激素无明显相关。我们的结果说明,降低猪日粮蛋白水平可下调小肠Ca SR基因表达和血液中CCK等胃肠激素的分泌,日粮蛋白水平对胃肠激素分泌的影响可能通过Ca SR介导。
The aim of this study was to investigate the effect of dietary protein levels on the expression of calcium-sensing receptor (Ca SR) gene and blood gut hormones in pigs at different physiological stages and to explore the effects of dietary protein levels on Ca SR gene expression and Gastrointestinal hormone secretion relationship. Choose healthy and weight 9.57 ± 0.64 kg Du × long × large ternary hybrid weaned piglets, 35kg (36.47 ± 0.20) kg pigs and 60 kg (62.30 ± 0.07) kg fattening pigs each The 18 piglets in each stage were randomly divided into 3 groups with 6 heads in each group and raised in a single bar. Based on the corn-soybean meal diet, the crude protein levels of weaned piglets were 20%, 17%, 14% The crude protein level of the growing pigs was 18%, 15% and 12% respectively. The crude protein levels of the finishing pigs were 16%, 13% and 10% respectively, and the feeding periods were 45, 30 and 50 days respectively. After the experiment, Pre-vena cava blood and small intestine tissues were collected, and the level of gastrointestinal hormone and the expression of Ca SR in various tissues of small intestine were measured. The results showed that when the dietary protein level decreased, Ca SR gene expression in piglets decreased at different stages (P <0.05), and the serum levels of CCK, GLP-1, The concentration of PYY decreased significantly, the concentrations of serum CCK and GIP in the growing pigs also decreased significantly, but only the GIP concentration in the finishing pigs decreased significantly (P <0.05). The correlation analysis showed that the piglets were empty, Ca SR expression in ileum was positively correlated with GLP-1 and GIP in blood (P <0.05), and Ca SR expression in ileum was positively correlated with PYY in blood (P <0.05) (P <0.05), but Ca SR expression in empty and ileum was significantly and positively correlated with GIP (P <0.05). There was no significant correlation between Ca SR expression and gut hormones in fattening pigs. Our results show that reducing dietary protein levels in pigs downregulates Ca SR gene expression in the small intestine and secretion of gut hormones such as CCK in the blood. The effects of dietary protein levels on gut hormone secretion may be mediated through Ca SR.