An experiment was conducted in a singly factorial design to study the effect of glycyl-glutamine dipeptide on enzyme activity, cell proliferation and apoptosis of jejunal tissues from weaned piglets at different glycy...An experiment was conducted in a singly factorial design to study the effect of glycyl-glutamine dipeptide on enzyme activity, cell proliferation and apoptosis of jejunal tissues from weaned piglets at different glycyl-glutamine concentration levels of 2, 4, 10, 20, and 30 mmol L-1, respectively. The glutaminase activity, diamine oxidase (DAO) activity, cell peoliferation, apoptosis, and perotein metabolism were measured by the tissue culture method in vitro using jejunal tissues. The immunohistochemical method was used to study the cell proliferation and apoptosis of jejunal tissues. The results showed that compared to the blank control, the percentage and MOD value of BrdU-positicve cells incubated with glycyl-glutamine dipeptide solution were significantly (P<0.05) increased. Accordingly, the percentage and MOD value of caspase-3-positive cells from tissue incubated with glycyl-glutamine dipeptide were notably lower (P<0.05) than that from the control treatment. The glycyl-glutamine dipeptide increased the glutaminase activity, DAO activity and protein content of jejunal tissues, as the dipeptide concentration was on the rise (P<0.05). These results indicated that glycyl-glutamine dipeptide affected the jejunum development and adaptation of weaned piglets, and the function might be fulfilled by enhancing the glutamine-related enzyme activity, thereby increasing the consumption of glutamine, and then improving the jejunal cell proliferation and suppressing cell apoptosis. The effects of glycyl-glutamine dipeptide relied in a dose-dependent manner, and the maximum effect was achieved at 20-30 mmol L-1 glycyl-glutamine dipeptide.展开更多
To investigate the tissue deposition and elimination of melamine (MEL) in broilers, a total of 1 920 commercial 1-d-old male Cobb broilers were randomly allotted to 6 treatments with diets contaminated by MEL at 0, 2,...To investigate the tissue deposition and elimination of melamine (MEL) in broilers, a total of 1 920 commercial 1-d-old male Cobb broilers were randomly allotted to 6 treatments with diets contaminated by MEL at 0, 2, 10, 30, 50, 100 mg kg-1 of diet for 42 d, and followed MEL withdrawal from diet at 50 or 100 mg kg-1 of diet for 96 h. The MEL was found in residue of plasma, liver, kidney, breast, and leg muscle with the highest level in kidney and in dose response manner (except in kidney), but no time response (except in plasma). The MEL residue in organ tissue was below the safe level of 50 μg mL-1 in blood or 50 μg kg-1 in tissues proposed by the US FSIS when MEL in diet was lower (2 mg kg-1). The MEL in tissues was eliminated by withdrawal MEL from diets. The elimination half-life of MEL was from 3.2 to 6.6 h, and the clearance time, when MEL residue concentration under limit detection, was from 18.0 to 31.4 h.展开更多
基金Sichuan Provincial Education Department of Outstanding Academic and Technical Youth Leadership Fund (2010JQ0043)the specific research supporting program for academic sustentation research team in Sichuan Agricultural University, China, for their financial supports
文摘An experiment was conducted in a singly factorial design to study the effect of glycyl-glutamine dipeptide on enzyme activity, cell proliferation and apoptosis of jejunal tissues from weaned piglets at different glycyl-glutamine concentration levels of 2, 4, 10, 20, and 30 mmol L-1, respectively. The glutaminase activity, diamine oxidase (DAO) activity, cell peoliferation, apoptosis, and perotein metabolism were measured by the tissue culture method in vitro using jejunal tissues. The immunohistochemical method was used to study the cell proliferation and apoptosis of jejunal tissues. The results showed that compared to the blank control, the percentage and MOD value of BrdU-positicve cells incubated with glycyl-glutamine dipeptide solution were significantly (P<0.05) increased. Accordingly, the percentage and MOD value of caspase-3-positive cells from tissue incubated with glycyl-glutamine dipeptide were notably lower (P<0.05) than that from the control treatment. The glycyl-glutamine dipeptide increased the glutaminase activity, DAO activity and protein content of jejunal tissues, as the dipeptide concentration was on the rise (P<0.05). These results indicated that glycyl-glutamine dipeptide affected the jejunum development and adaptation of weaned piglets, and the function might be fulfilled by enhancing the glutamine-related enzyme activity, thereby increasing the consumption of glutamine, and then improving the jejunal cell proliferation and suppressing cell apoptosis. The effects of glycyl-glutamine dipeptide relied in a dose-dependent manner, and the maximum effect was achieved at 20-30 mmol L-1 glycyl-glutamine dipeptide.
基金supported by the Special Fund for Establishment of Maximum Residue Limit of MEL in feed (Ministry of Agriculture,China)
文摘To investigate the tissue deposition and elimination of melamine (MEL) in broilers, a total of 1 920 commercial 1-d-old male Cobb broilers were randomly allotted to 6 treatments with diets contaminated by MEL at 0, 2, 10, 30, 50, 100 mg kg-1 of diet for 42 d, and followed MEL withdrawal from diet at 50 or 100 mg kg-1 of diet for 96 h. The MEL was found in residue of plasma, liver, kidney, breast, and leg muscle with the highest level in kidney and in dose response manner (except in kidney), but no time response (except in plasma). The MEL residue in organ tissue was below the safe level of 50 μg mL-1 in blood or 50 μg kg-1 in tissues proposed by the US FSIS when MEL in diet was lower (2 mg kg-1). The MEL in tissues was eliminated by withdrawal MEL from diets. The elimination half-life of MEL was from 3.2 to 6.6 h, and the clearance time, when MEL residue concentration under limit detection, was from 18.0 to 31.4 h.
