| Abstract: | Four crossbred(Duroc x Landrace x Yorkshire)boars,weighing an average of 22.40±1.08 kg and fitted with permanent catheters in their portal and mesentedc veins as well as their carotid artery,were utilized in a 4 x 4 latin square design experiment in order to investigate the effects of different starch sources(maize,brown rice,sticky dee,and resistant starch)on the absorption of energy sources through the portal vein.Portal blood flow averaged 30.68,28.40,29.99,and 30.12 mL/min per kg BW for pigs fed the maize,brown rice,sticky dee,and resistant starch diets,respectively,and did not differ (P>0.05)between treatments.The absorptions of glucose,plasma ammonia,and total amino acids were significantly lower(P<0.05)in pigs fed the resistant starch diet than pigs fed the other starch sources.In contrast,significantly(P<0.05)higher amounts of propionate and total volatile fatty acids were absorbed from the portal vein of pigs fed resistant starch than pigs fed diets based on maize,brown rice,or sticky rice.In addition,significantly(P<0.05)more lactic acid was absorbed from the portal vein by pigs fed the sticky rice diet than pigs fed the other three diets.The energy absorbed from the portal vein in the form of glucose and amino-N as well as the total energy absorbed was significantly(P<0.05)lower in pigs fed the resistant starch diet than pigs fed the other three starch sources.In contrast,theamount of energy absorbed in the form of volatile fatty acids was significantly(P<0.05)higher in pigsfed resistance starch than pigs fed the other three starch sources.The total energy absorbed through the portal vein as a percentage of the gross energy and digestible energy consumed in pigs fed maize were 50.8% and 54.6%,respectively,which were significantly(P<0.05)higher than the values in pigs fed resistant starch(41.5% and 46.6% respectively).The results indicate that energy is absorbed in different forms and with different utilization efficiencies in the digestive tract of pigs as a result of feeding different starch sources.Starch sources supplying most of their energy in the form of glucose had higher energy utilization efficiencies,while starch sources supplying most of their energy in the form of volatile fatty acids or lactic acid had lower energy utilization efficiencies. |
