The Effect Of Ration Protein Levels On Metabolism And Transform Of Endogenic Urea In Goat

In this paper,four goats fitted with mesenteric and portal venous,jugular vein,carotid artery catheters were used as experimental animals , a 4×4 Latin Square experiment was carried out to study the effect of ration protein levels on metabolism and transform of endogenic urea in goat. Four different ration protein levels were 8.5%(A),11.0%(B),13.5%(C)and 16.0%(D), respectively. The results showed that:1. The apparent digestilities of nitrogen increased with the increase of ration protein levels,but there was no significant difference in the four groups(P>0.05). The retained nitrogen(RN) in B group was much higher than that in A group(P<0.01) and C and D group(P<0.05). The highest retained nitrogen 0.36g/d·w^0.75 was observed in the the protein levelof 11.0%.2. The blood pH of artery, portal and mesenteric vein all increased with the increase of ration protein levels,but altered in the normal physiological range(pH7.32～7.54), there was no significant difference in the four groups(P>0.05). The blood pH all increased to the highest points after feeding 4 hours,then decreased until the next time's feeding.3.The enrichment of protein-¹⁵N in the blood of portal and mesenteric vein all increased with the increase of ration protein levels,but there was no significant difference in the four groups(P>0.05). The enrichment of total-¹⁵N,NH₃-¹⁵N,urea-¹⁵N and free amino acid- ¹⁵N were get to the maximum (P>0.05, P<0.05 or P<0.01)in B group ,the enrichment were 0.0549,0.0123,0.0137,0.0094%å’Œ0.0486,0.0103,0.0107,0.0084% respectively.4.The net flux of protein-¹⁵N in PDV and MDV all increased with the increase of ration protein levels,but there was no significant difference in the four groups(P>0.05). The net flux of total-¹⁵N,NH3-¹⁵N,urea-¹⁵N and free amino acid- ¹⁵N were get to the maximum (P>0.05, P<0.05 or P<0.01)in B group ,the net flux were 784.69,2.09,-14.62,3.87mg/d and 330.40,0.96,-5.17,1.48mg/d respectively.