Effects Of Different Metabolic Glucose Levels On Digestion,Absorption And Growth Of Amino Acids In Piglets

The study was conducted to investigate the effects of different metabolizable glucose levels on the digestion,absorption and growth of amino acids(AA)in piglets.We aimed to determine the effects of dietary glucose on the loss of intestinal amino acids and the net absorption of amino acids in the portal vein.Then preparations of appropriate metabolizable glucose formula feed which contains different levels of standardized ileal digestibility of amino acids.This study include three parts: 1.The effect of different metabolizable glucose levels on the loss of intestinal amino acids in piglets.A total of 24 25-day-old weaned piglets(6.67±0.14 kg)were selected and assigned to four groups which dietary with 25.92 %,30.75 %,35.47 % and 40.17 % MG level under the same energy and nitrogen.Each group had 6 replicates with 1 per replicate.A T-Cannula were implanted into the terminal ileum.The chime from ileum were collected,then determinating the content of starch and amino acid,and determinating the concentration of amino acid in the feedstuff.Then the amino acid disappearance of the intestinal tract was calculated.The results showed that starch digestibility in small intestinal of 4 groups piglets increased with the increase of MG level.The disappearance of Asp,Thr,Ser,Glu,Gly,Ile,Leu,Tyr,Phe,His,Lys,Arg in the amount of amino acid loss in small intestinal reached the maximum at the level of 30.75 % MG,and the group were significant higher than other groups(P<0.01).The intestinal disappearance of Ala and Val between the 4 groups were significantly difference(P<0.01),and reached the maximum at 35.47 % MG level.The intestinal disappearance of Cys and Met in 40.17 % MG level was significantly higher than that in the other 3 groups(P<0.01),showing a gradual upward trend.The intestinal disappearance of EAA,NEAA,GAA and BCAA in the 4 groups increased with the increase of MG levels in the diet(P<0.01).In this experiment,there was a quadratic relationship between the diet MG level and the intestinal disappearance of amino acids in the piglets,and the total amount of intestinal amino acid disappearance reached the maximum at the level of 30.75 % MG.2.Effects of different levels of metabolizable glucose on portal vein net absorption of amino acid in piglets.A total of 24 25-day-old weaned piglets(6.67±0.14 kg)were selected and assigned to four groups which dietary with 25.92 %,30.75 %,35.47 % and 40.17 % MG level under the same energy and nitrogen.Each group had 6 replicates with 1 per replicate.The vascular embedded tube were installed to vessels of femoral artery,portal vein and mesentery.Infused 1 % PAH through mesenteric catheters when the piglets restored to health.We exsanguinate piglet’s blood from portal vein,artery.The content of amino acids difference between 2 points brought us the portal vein net absorption of AA.The results display that net absorption of Ile and Tyr in the 35.47% MG diet was significantly higher than that of the other groups(P<0.01),while the net absorption of Arg in the portal vein fluctuated in a certain range with the fluctuation of glucose level in the diet,and reached the maximum(P<0.05)at the level of 40.17 % MG.With the increase of dietary MG levels,the net absorption of Asp,Thr,Ser,Glu,Gly,Ala,Cys,Val,Leu,Phe,His,Lys,Pro increased and reached the maximum on the 30.75 % MG.Conclude by the classification,the total net absorption of portal vein in EAA,NEAA,GAA and BCAA reached the maximum at 30.75 % MG(P<0.01).The PDV tissue consumption of Asp、Thr、Ser、Phe、Gly、Ala、Cys、His、Ile achieved minimum value at 30.75 % MG(P<0.01),and consumption of Arg、Tyr、Val achieved maxmum value simultaneously(P<0.01).With the increase of dietary MG levels,the consumption of Arg、Tyr、Val was declined gradually.In this experiment,there was a linear relationship between the MG level of diet and the net absorption of the portal vein of piglets.The total net absorption of amino acids in the portal vein reached the maximum at the level of 30.75 % MG,and PDV tissue consumption of amino acids reached minmun at the same level.3.Effect of different crude protein levels on the growth performance of weaned piglets under appropriate metabolizable glucose level.A total of 24 25-day-old weaned piglets(9.69±1.53 kg)were selected and assigned to four groups which dietary with 30.75 % MG under different level of crude protein.The experimental period was 20 days.The metabolizable glucose of diet was 30.75 %,and crude protein were 15.50 %,17.00 %,18.50 %,20.00 %,respectively.The growth performance of piglets was analyzed according to the feed intake,1 d and 30 d weight.The results showed that there was no significant difference in daily average feed intake,daily gain and feed conversion efficiency between the 4 groups(P>0.05).There was no difference between all groups with the average daily intake,daily gain and feed conversion efficiency of 1-14 d.But the average daily intake and feed conversion efficiency of 15-30 d were significant difference between group Ⅰ,Ⅱ and group Ⅲ,Ⅳ(P<0.01).The level of protein had no significant effect on the growth performance of weaned piglets under the condition of appropriate level of MG.On the condition of this experimental,appropriate MG level can significantly alleviate the low growth performance of piglets caused by low protein.MG should dietary less than 15.50 % during 1-14 d,and dietary less than 18.50 % during 15-30 d.