【摘要】：本文旨在研究不同無機磷水平和植酸酶對斷奶仔豬骨骼鈣磷代謝以及腸道相關基因表達的影響。試驗選用224頭初重(9.12±0.29 kg)相近、健康狀況良好的“杜×長×大”三元雜交斷奶仔豬,隨機分為7個處理,每個處理4個重復,每個重復8頭。處理1為對照組,飼喂基礎飼糧;處理2~6保持鈣水平(7.00 g/kg)不變,添加750 FTU/kg的植酸酶,無機磷添加量分別為對照組的100%、75%、50%、25%、0%(鈣磷比為1.17~1.79:1);處理7為負對照,無機磷添加量為0%,且不添加植酸酶。試驗期35 d。結果表明:當飼糧無機磷添加量為對照組的0%時,添加植酸酶使脛骨及肋骨磷含量極顯著升高(P0.01);血清CT、OPN顯著降低(P0.05)。飼糧無機磷添加量為100%條件下,添加植酸酶,骨合成生化指標BAP濃度顯著升高(P0.05);骨吸收生化指標CTX-Ⅰ、OPN、TRACP-5b顯著降低(P0.01)。加植酸酶的條件下(750 FTU/kg),降低無機磷的添加量,骨骼鮮重、脫脂重、骨骼鈣、磷及灰分含量呈線性及二次降低(P0.05);血清CT、l,25-(OH)2D3及骨吸收生化指標CTX-Ⅰ、OPN、TRACP-5b、顯著升高(P0.05),且呈線性和二次相關(P0.01);血清FGF23及骨合成生化指標BAP、BGP、OPG顯著降低(P0.05),且呈線性和二次相關(P0.01)。說明低磷飼糧會減弱骨合成作用,促進骨吸收。骨合成生化指標BAP、OPG、BGP與血清P、FGF23以及脛骨鈣、磷、灰分含量正相關,與血CT、l,25-(OH)2D3含量負相關;骨吸收生化指標CTX-Ⅰ、OPN、TRACP5b與血CT、l,25-(OH)2D3呈正相關,與血清P、FGF23以及脛骨鈣、磷、灰分含量負相關;且BAP、OPG、BGP與CTX-Ⅰ、OPN、TRACP5b呈負相關。說明骨代謝生化指標能反應機體骨骼鈣磷代謝狀況。飼糧無機磷添加量為100%和0%條件下,添加植酸酶,斷奶仔豬小腸NaPi-IIb mRNA的表達量顯著降低(P0.01)。加植酸酶條件下,隨飼糧無機磷添加量的降低,斷奶仔豬小腸NaPi-IIb mRNA(P0.01)以及十二指腸、腎臟CaBP-D9k mRNA表達量(P0.05)顯著升高;空腸與回腸的CaBP-D9k mRNA的表達量差異不顯著(P0.05)。無機磷水平和植酸酶對斷奶仔豬小腸SGLT-1 mRNA的表達量無顯著影響(P0.05)。組化結果顯示,NaPi-IIb蛋白主要分布于小腸吸收細胞細胞質,且沿紋狀緣濃度較大,固有層部分細胞細胞質中也存在。100%、50%、0%三個磷水平,小腸絨毛吸收細胞細胞質著色逐漸變深,說明細胞內NaPi-IIb蛋白濃度隨磷水平降低增大。低磷飼糧可以刺激腸道磷的主動吸收,提高其吸收效率。綜上所述:植酸酶能改善斷奶仔豬的骨骼性能,且在低磷條件下效果更明顯;加植酸酶飼糧,降低無機磷的添加量會降低斷奶仔豬骨骼鈣、磷及灰分含量,并促進小腸NaPi-IIb蛋白及其mRNA的表達;骨代謝生化指標能準確反映骨代謝狀況,且比常規(guī)指標更敏感。綜合各項指標,在斷奶仔豬飼糧中添加植酸酶可以替代25%(4.02 g/kg)的磷酸氫鈣添加量。
[Abstract]:The purpose of this study was to study the effects of different inorganic phosphorus levels and phytase on calcium and phosphorus metabolism and intestinal gene expression in weaned piglets. Two hundred and twenty-four weaned piglets with similar initial weight (9.12 鹵0.29 kg) and good health were randomly divided into 7 treatments, 4 replicates per treatment and 8 piglets per replica. Treatment 1 was used as control group, fed basic diet, treatment 2 + 6 kept calcium level unchanged (7. 00 g/kg), phytase of 750 FTU/kg was added, inorganic phosphorus content was 100 75% of control group (Ca / P ratio was 1. 17 鹵1. 79: 1), treatment 7 was negative control. The amount of inorganic phosphorus was 0 and no phytase was added. The trial period was 35 days. The results showed that the contents of phosphorus in tibia and rib were significantly increased (P0.01) and serum CT,OPN was significantly decreased (P0.05) when inorganic phosphorus was added to diet as the control group (P < 0.05). When dietary inorganic phosphorus was added to 100%, the concentration of BAP increased significantly (P0.05), and the biochemical indexes of bone resorption (CTX- 鈪，

本文編號：2262143