本试验旨在研究标准全消化道可消化钙(STTD Ca)和标准全消化道可消化磷(STTD P)含量对7～25 kg断奶仔猪钙、磷吸收的影响.选取21日龄、体重接近的杜长大杂交断奶仔猪144头,随机分为6组,每组6个重复,每个重复4头猪(阉公猪和母猪各2头).第1～6组饲粮中 STTD Ca 和 STTD P 的比例均为 1.2,STTD P 含量分别为 0.18％、0.26％、0.34％、0.42％、0.50％、0.58％,STTD Ca 含量分别为 0.216％、0.312％、0.408％、0.504％、0.600％、0.696％.试验期42 d.结果表明:1)随着饲粮中STTD Ca和STTD P的含量逐渐升高,血清碱性磷酸酶活性逐渐降低,但组间没有显著差异(P＞0.05),血清降钙素(CT)、甲状腺素(T4)、1,25二羟维生素D3[1,25(OH)D3]、甲状旁腺素(PTH)含量逐渐升高,且6组显著高于1组(P＜0.05).1组血清中钙含量显著低于其他组(P＜0.05),其中2、4和6组的血清钙含量较于其他组更高;1组血清磷含量显著高于5组(P＜0.05).2)饲粮中STTD Ca和STTD P的含量逐渐升高对胃内容物及盲肠内容物pH无显著影响(P＞0.05).3)所有组肠道结构完整,1和2组十二指肠绒毛高度/隐窝深度显著高于5和6组(P＜0.05),2组空肠绒毛高度/隐窝深度显著低于5组(P＜0.05).4)在十二指肠中,2和3组维生素D受体(VDR)的基因相对表达量显著高于1和5组(P＜0.05),1和2组钙磷结合蛋白1(CALB1)的基因相对表达量显著高于4、5和6组(P＜0.05),1组细胞色素P450家族成员24A1(CYP24A1)的基因相对表达量显著高于其他组(P＜0.05);在空肠中,4和6组的钙离子通道6(TRPV6)的基因相对表达量显著高于2和5组(P＜0.05),6组S100钙结合蛋白G(S100G)的基因相对表达量显著高于2组(P＜0.05),4组ATP酶质膜钙离子转运蛋白1(ATP2B1)的基因相对表达量显著高于2组(P＜0.05),5和6组溶质载体家族蛋白34成员A3(SLC34A3)的基因相对表达量显著高于1和2组(P＜0.05),1组CYP24A1的基因相对表达量显著高于其他组(P＜0.05);在回肠中,CYP24A1和SLC34A3的基因相对表达量逐渐降低,1和2组CYP24A1的基因相对表达量显著高于其他组(P＜0.05),2组SLC34A3的基因相对表达量显著高于其他组(P＜0.05);在结肠中,1组TRPV6、ATP2B1和CALB1的基因相对表达量显著高于其他组(P＜0.05).在肾脏中,甲状旁腺素1受体(PTHIR)和钙离子通道5(TRPV5)的基因相对表达量先升高后降低,当升高到NRC(2012)推荐STTD P添加量(STTD P含量为0.34％～0.42％)时到达最大;3和4组PTH1R的基因相对表达量显著高于其他组(P＜0.05),4组TRPV5的基因相对表达量显著高于其他组(P＜0.05).在肝脏中,2组SLC34A3的基因相对表达量显著高于4组(P＜0.05),1组CALB1的基因相对表达量显著高于其他组(P＜0.05).综上所述,饲粮中STTD Ca和STTD P的比例为1.2时,随着饲粮中STTD Ca和STTD P的含量逐渐升高,十二指肠和结肠对钙、磷的吸收能力逐渐减弱,空肠对钙、磷的吸收能力逐渐增强,肝脏对钙、磷吸收能力逐渐降低.当饲粮中STTD Ca和STTD P的含量增加到NRC(2012)推荐的STTD P添加量(饲粮STTD P含量为0.34％～0.42％)时,肾脏对钙、磷重吸收的能力最强.结合血清钙、磷含量数据,当饲粮中STTD Ca和STTD P的含量分别在0.216％～0.312％和0.18％～0.26％时,断奶仔猪能有效利用饲粮钙、磷.
Effects and Mechanism of Standard Total Tract Digestibility Calcium and Phosphorus Contents on Calcium and Phosphorus Absorption in Gut-Liver-Kidney Axis of Weaned Piglets
The objective of this study was to investigate the effects of standardized total tract digestibility Ca(STTD Ca)and standardized total tract digestibility P(STTD P)contents on calcium and phosphorus absorp-tion in 7 to 25 kg weaned piglets.A total of 144 weaned piglets with a similar body weight at 21 days of age were randomly divided into 6 groups,with 6 replicates in each group and 4 pigs(two castrated boars and two sows)in each replicate.The proportions of STTD Ca and STTD P in the diet were 1.2,and the contents of STTD P were 0.18％,0.26％,0.34％,0.42％,0.50％and 0.58％,respectively,and the contents of STTD Ca were 0.216％,0.312％,0.408％,0.504％,0.600％and 0.696％,respectively.The trial period was 42 days.The results showed as follows:1)with the gradual increase of the contents of STTD Ca and STTD P in the diet,the serum alkaline phosphatase activity gradually decreased,but there was no significant difference be-tween the groups(P＞0.05),and the serum contents of calcitonin(CT),thyroxine(T4),1,25 dihydroxy vi-tamin D3[1,25(OH)D3]and parathyroid hormone(PTH)increased gradually,and group 6 were significant-ly higher than group 1(P＜0.05).The serum calcium content in group 1 was significantly lower than that in other groups(P＜0.05),and the serum calcium content in groups 2,4 and 6 was higher than that in other groups.The serum phosphorus content in group 1 was significantly higher than that in group 5(P＜0.05).2)The contents of STTD Ca and STTD P in the diet increased gradually,and there was no significant effect on the pH of gastric contents and cecal contents(P＞0.05).3)The intestinal structure of all groups was intact,the duodenal villus height/crypt depth in groups 1 and 2 was significantly higher than that in groups 5 and 6(P＜0.05),and the jejunal villus height/crypt depth in group 2 was significantly lower than that in group 5(P＜0.05).4)In the duodenum,the relative expression levels of vitamin D receptor(VDR)gene in groups 2 and 3 were significantly higher than those in groups 1 and 5(P＜0.05),the relative expression levels of calci-um and phosphorus binding protein 1(CALB1)gene in groups 1 and 2 were significantly higher than those in groups 4,5 and 6(P＜0.05),and the relative expression levels of cytochrome P450 family member 24A1(CYP24A1)gene in group 1 were significantly higher than those in other groups(P＜0.05).In the jejunum,the expression levels of calcium channel 6(TRPV6)gene in groups 4 and 6 were significantly higher than those in groups 2 and 5(P＜0.05),the relative expression levels of S100G gene in group 6 was significantly higher than those in group 2(P＜0.05),the relative expression level of ATPase plasma membrane calcium ion transporter 1(ATP2B1)gene in group 4 was significantly higher than that in group 2(P＜0.05),the relative expression levels of A3(SLC34A3)member of solute carrier family protein 34 in groups 5 and 6 that signifi-cantly higher than that in groups 1 and 2(P＜0.05),and the relative expression level of CYP24A1 genes in group 1 was significantly higher than those in other groups(P＜0.05).In the ileum,the relative expression levels of CYP24A1 and SLC34A3 genes decreased gradually,and the relative expression levels of CYP24A1 gene in groups 1 and 2 were significantly higher than those in other groups(P＜0.05),and that of SLC34A3 gene in group 2 was significantly higher than that in other groups(P＜0.05).In the colon,the relative expres-sion levels of TRPV6,ATP2B1 and CALB1 genes in group 1 were significantly higher than those in other groups(P＜0.05).In the kidney,the gene expression levels of parathyroid hormone 1 receptor(PTH1R)and calcium ion channel 5(TRPV5)increased first and then decreased,and reached the maximum when it in-creased to the recommended STTD P addition in NRC(2012)diet(STTD P content was 0.34％to 0.42％).The relative expression level of PTH1R gene in groups 3 was significantly higher than that in the other groups(P＜0.05),and the relative expression of TRPV5 gene in the group 4 was significantly higher than that in the other groups(P＜0.05).In the liver,the relative expression level of SLC34A3 gene in group 2 was significant-ly higher than that in group 4(P＜0.05),and the relative expression level of CALB1 gene in group 1 was sig-nificantly higher than that in other groups(P＜0.05).In summary,when the ratio of STTD Ca and STTD P in the diet is 1.2,with the gradual increase of the contents of STTD Ca and STTD P in the diet,the absorption capacity of calcium and phosphorus in duodenum and colon gradually weaken,the absorption capacity of calci-um and phosphorus in jejunum gradually increase,and the absorption capacity of calcium and phosphorus in the liver gradually decrease.When the contents of STTD Ca and STTD P in the diet increase to the STTD P addi-tion recommended by NRC(2012)(the content of STTD P in the diet is 0.34％to 0.42％),the ability of the kidney to reabsorb calcium and phosphorus is the strongest.Combined with serum calcium and phosphorus da-ta,when the contents of STTD Ca and STTD P in the diet are 0.216％to 0.312％and 0.18％to 0.26％,re-spectively,weaned piglets can effectively use the calcium and phosphorus in the diet.[Chinese Journal of Ani-mal Nutrition,2024,36(7):4243-4257]
weaned pigletsSTTD CaSTTD Pintestinekidneylivercalcium and phosphorus absorption
万方数据
维普
