| This study was conducted to determine the effect of oral administration of N-carbamoylglutamate on 7-to 21-d-old suckling piglets. The "Duroc×(Landrace×Yorkshire)" three crossbred suckling piglets (n=30, 4-d-old) were selected from 6 nests which parity and initial average weight(2.036±0.181kg) was similer. The piglets were randomly divided in 5 treatment groups, each group of 6 piglets. Everyday, each group per kilogram of body weight fed with different levels of N-carbamoylglutamate: The control group (0 mg); treatment groupⅠ(100 mg); treatment groupⅠ(150 mg); treatment groupⅢ(200 mg); treatment groupⅢ(250 mg). Pre trial period was 3d, the test was official beginning at 7-d-old, and 21-d-old over, test period was 14d. During the whole test, sow-reared piglets received oral administration of NCG 2 times/d, sow-reared piglets were weighing every three days. The end of the experiment, each group chosed 2 suckling piglets, blood samples were collected, and then slaughter. The results showed that:(1)Growth performance: Oral administration with 100,150 and 200 mg NCG/kg BW to 7-14-d-old suckling piglets, the body weight and the average daily gain were improved,but were not not significant (P>0.05), compared with the control piglets.The average daily weight gain was significantly increased,when the 14-21-d-old suckling piglets received 100 or 150mg NCG/kg BW everyday(P<0.05). The whole of the experiment , oral administration of 100 and 150 mg NCG/kg BW to suckling piglets significantly increased the body weight(10.5% and 14.6%, respectively) and the average daily gain (14.98% and 21.09% , respectively)(P<0.05).(2) Internal organs indexes: The heart, liver, kidney, stomach and small intestine relative weight of suckling piglets in the oral administration of N-carbamoylglutamate treatment groups were significantly higher than those in control group (P<0.05), the relative weigh of heart was the highest in the 150mg of NCG/kg BW treatment group(increased by 31.66%). The liver was the highest in the 200mg NCG/kg BW treatment group (P<0.05), and was increased by 14.79%. Kidney was the most significant effect in the100mg of NCG/kg BW treatment group (by 24.26%); Oral administration of 100 and 150mg of NCG/kg BW, the relative weight of stomach was increased significantly by 13.05%'9.55%, respectively (P<0.05); the small intestine relative weight was increased significantly by 13.43% in the 150mg NCG/kg BW treatment group(P<0.05). Compared with the control group, oral administration of NCG had no significant effect on spleen and lung(P>0.05), but as NCG adding amount increasing, the relative spleen weight also increased.(3) Blood biochemical indexes: Oral administration of NCG on plasma alanine aminotransferase and aspartate aminotransferase, urea nitrogen had no significant effect (P>0.05), and oral administration of 100,150,200mg of NCG/kg BW everyday decreased the plasma concentrations of glucose and ammonia (P<0.05). The 200mg/kg treatment group decreased by 34.93% ; the level of plasma ammonia with the NCG supplementation increased,significantly decreased, the 250mg/kg group was lowest(decreased by 36.02%). Oral administration with 150mg of NCG/kg BW to suckling piglets, increased the plasma concentrations of albumin 33.66% (P<0.05), total protein 16.09% (P<0.05); suckling piglets per day orally100 and 150 mg of NCG/kg BW increased the plasma NO level (62.50% and 109.37%, respectively) (P<0.05) and the plasma alkaline phosphatase concentrations, but the difference was not significant (P>0.05).(4) Plasma hormone levels: Suckling piglets reveiced N-carbamoylglutamate, had a significant increase in plasma insulin levels (P<0.05), and in the 200 mg NCG/kg BW treatment group was the highest(increased by 26.16%) .Oral administration of 100 or 150 mg NCG/kg BW significantly increased the level of growth hormone by 17.81% and 15.07% (P<0.05). Suckling piglets fed with the N-carbamoylglutamate significantly reduced the plasma cortisol levels (P<0.05), when the dosage of 150mg/kg BW was lowest, compared with the control group decreased 49.21%.(5) Plasma immuneglobulin: Compared with the control group, Oral administration of 100,150 and 200mg NCG/kg BW significantly increased IgM (P<0.05); suckling piglets fed with NCG significantly increased IgG concentrations (P<0.05).When the suckling piglets fed with 150mg NCG/kg BW, immunoglobulin concentrations were the highest.Compared with the control group were increased by 29.13%%、69.72% and 69.7%. Then with the adding amount increased, IgA, IgG and IgM decreased gradually.(6) Plasma amino acid level: Oral administration of NCG to 7-21-d-old suckling piglets significantly increased the plasma concentrations of arginine. In which 150mg/kg treatment group, the effect is most significant, increased by 43.84% (P<0.05). Plasma citrulline content in oral administration of 150mg/kg NCG were significantly increased by 45.23% (P<0.05). Oral administration of NCG had no effect on plasma ornithine, lysine and histidine concentrations(P>0.05).(7) Intestinal morphology: Compared with the control group, Oral administration of NCG to suckling piglets, increased villous height (P<0.05) and villus height/crypt depth in duodenum (P<0.05) , in which 150mg/kg treatment group was the most obvious effect, improved 29.37% and 51.57% respectively. When the suckling piglets received 150, 200 and 250 mg NCG/kg BW, the crypt depth in duodenum was significantly reduced by 14.63%, 9.29% and 8.61% (P<0.05). 150mg of NCG/kg BW treatment group increased villus height in jejunal by 19.48% (P<0.05), other groups had no significant difference (P>0.05). In jejunum, 100 and 150mg of NCG/kg BW treatment groups significantly reduced jejunal crypt depth 12.91% and 15.38% (P<0.05), and increase in villus height/crypt depth by 30.34% and 41.3%(P<0.05). When the supplementary volume of NCG was 150mg/kg BW everyday, the ileal villus height and villus height/crypt depth significantly increased by 26.1% and 62.45% (P<0.05), the other groups were elevated but with the control group was not significant (P>0.05). Oral administration of 100, 150 and 200mg NCG/kg BW, significantly reduced the crypt depth (P<0.05).(8) The activity of carbamoyl phosphate synthase-I in the small intestine: NCG enhanced intestinal carbamyl phosphate synthase I activity. Compared with control piglets, oral administration of 100,150 and 200mg NCG/kg BW to the sow-reared piglets does dependently increased the activity of carbamoyl phosphate synthase I in duodenal (38.52%, 58.57% and 29.59%, respectively)(P<0.05), and 250mg NCG/kg BW treatment group had no significant (P>0.05). 100mg/kg treatment group significantly improved carbamoyl phosphate synthase I activity in jejunal (97.17%) (P<0.05). Oral administration of 150mg NCG/kg BW significantly increased carbamoyl phosphate synthase I activity in ileal by 24.80% (P<0.05).(9) The gene expression of carbamoyl phosphate synthase- I in the small intestine: Compared with the control group, Sow-reared piglets were fed with 150 mg of NCG/kg BW, significantly increased the gene expression of carbamoyl phosphate synthase- I in duodenal 26.92% (P<0.05); 100 and 150 mg of NCG/kg BW treatment groups significantly improved the gene expression of carbamoyl phosphate synthase I (P<0.05) in jejunum(59.37% and 21.87%, respectively) and ileum (23.33% and 36.67%, respectively). Experimental determination of the gene expression of carbamoyl phosphate synthase-I in the kidney found that, kidney tissue has no PCR products, kidney without carbamoyl phosphate synthase I expression.These results indicate that complement a certain amount of NCG can promote the growth and improve the function of the gastrointestinal tract of suckling piglets, the NCG appropriate dosage of 7-21-d-old suckling piglets is 100~150mg/kg/d. |
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