胚蛋注射丙酮酸肌酸对肉鸡空肠消化吸收功能的影响

Effects of in ovo feeding of creatine pyruvate on jejunum digestion and absorption function in broilers

[目的]本文旨在研究胚蛋注射丙酮酸肌酸(creatine pyruvate,CrPyr)对肉鸡空肠黏膜酶活性、胃肠激素浓度、营养素转运载体及味觉感受体基因表达水平的影响。[方法]选取16日胚龄AA肉鸡商品代胚蛋720枚,随机分成3组,每组8个重复,每个重复30枚,分别设为空白对照组、盐水组(0.6 mL 0.75%生理盐水)、CrPyr组(12 mg CrPyr溶于0.6 mL 0.75%生理盐水)。在孵化17.5 d进行羊膜腔注射试验,每枚蛋重注射剂量为0.6 mL。出壳后,将每组的公雏挑出并称质量,并从各组选出与公雏平均体质量接近的80只公雏,随机均分成8个重复,饲养到出壳后21 d。分别在孵化19 d(-19 d)和出壳0、7、21 d采集空肠黏膜样本,测定空肠黏膜酶活性、胃肠激素浓度及营养素转运载体和味觉感受体基因mRNA表达水平。[结果]与对照组和盐水组相比,CrPyr组显著提高了孵化19 d鸡胚及出壳当天(0 d)肉鸡空肠黏膜二糖酶(蔗糖酶、麦芽糖酶)和碱性磷酸酶(AKP)的活性(P<0.05);CrPyr组显著提高了孵化19 d鸡胚和出壳当天(0 d)雏鸡空肠血管活性肠肽(VIP)的浓度(P<0.05),显著降低孵化19 d鸡胚、出壳7和21 d肉鸡空肠黏膜胃饥饿素的浓度(P<0.05);注射CrPyr显著上调出壳21 d肉鸡空肠氨基酸转运载体CAT 1基因的mRNA表达量(P<0.05);注射CrPyr显著上调孵化19 d鸡胚、出壳7和21 d肉鸡空肠肽转运载体1(PepT1)、钠依赖性葡萄糖转运载体1(SGLT1)、易化葡萄糖转运载体2(GLUT2)基因表达量(P<0.05),显著上调出壳当天(0 d)和7 d肉鸡空肠易化葡萄糖转运载体5(GLUT5)和b 0,+系统氨基酸转运载体(rBAT)、及B 0型氨基酸转运载体1(B 0AT1)基因表达量(P<0.05);注射CrPyr显著上调出壳0、7、21 d肉鸡空肠脂肪酸转运载体4(FATP4)基因表达水平(P<0.05)。此外,注射CrPyr显著上调孵化19 d和出壳7 d后味觉受体1(T1R1)基因表达水平(P<0.05)。[结论]胚蛋注射12 mg的CrPyr有利于提高肉鸡空肠消化和吸收能力。

[Objectives]The objectives of the present study was to examine the effects of in ovo feeding(IOF)of creatine pyruvate(CrPyr)on activity of mucosa enzymes,concentration of gastrointestinal hormones,gene expression of nutrient transporters and sensing receptors in jejunum of broilers.[Methods]At 16 d of incubation,a total of 720 fertile eggs(Arbor Acres broilers)containing viable embryos were selected and randomly divided into three treatment groups of 240 eggs(8 replicates in each treatment).Three groups consist of the following:control group;physiological saline injected group(0.6 mL physiological saline(0.75%));CrPyr injected group(0.6 mL physiological saline(0.75%)containing 12 mg CrPyr).On the 17.5 d of incubation,injection solution was injected into amniotic cavity for each fertile egg.Upon hatching,all male hatched chicks from one treatment were pooled and weighed.80 male chicks with similar weight close to average body weight of all the male chicks were selected and randomly allocated into 8 replicates.Jejunal mucosa samples were collected at 19 d of incubation(-19 d),the day of hatch(0 d),7 and 21 d after hatching.The activity of mucosa enzymes,concentration of gastrointestinal hormones,gene expression of nutrient transporters and sensing receptors in jejunum were measured.[Results]IOF of CrPyr significantly increased the activities of disaccharidase(sucrase,maltase)and alkaline phosphatase(AKP)in jejunal mucosa at-19 d and 0 d compared with saline and control groups(P<0.05).CrPyr group significantly increased the concentration of vasoactive intestinal peptide(VIP)of jejunum at-19 d and 0 d(P<0.05).At-19,7 and 21 d post-hatch,Embryos or chicks in CrPyr treatment group had a lower concentration of ghrelin of jejunal mucosa than those in control and saline groups(P<0.05).CrPyr group significantly enhanced the mRNA expression of CAT 1 gene in jejunum of broiler chicken at 21 d post-hatch(P<0.05).Increased gene expressions of jejunal peptide transporter 1(PepT1),sodium glucose transporter 1(SGLT1)and glucose transporter 2(GLUT2)were found at-19 d,7 and 21 d post-hatch in CrPyr group(P<0.05).IOF of CrPyr had increased mRNA expression levels of jejunal glucose transporter 5(GLUT5),amino acid transporter related to b 0,+(rBAT)and amino acid transporter related to B 0(B 0AT1)at 0 and 7 d post-hatch(P<0.05).mRNA expression levels of jejunal fatty acid transporter protein 4(FATP4)increased at 0,7 and 21 d post-hatch in CrPyr group(P<0.05).Meanwhile,CrPyr group showed higher mRNA expressions of jejunal taste receptor type 1 member 1(T1R1)at 0 d and 7 d post-hatch in comparison with saline and control group(P<0.05).[Conclusions]IOF of 12 mg CrPyr is beneficial to increasing the digestive and absorptive capacity of jejunum in embryos or broiler chickens.