EFFECT OF SOURCE OF STARCH ON NET PORTAL FLUX OF GLUCOSE, LACTATE, VOLATILE FATTY-ACIDS AND AMINO-ACIDS IN THE PIG

The ileal digestibilities of maize starch and native pea starch do not differ. However maize starch is digested faster than pea starch and t he ileal amino acid digestibility of a diet containing pea starch is l ower. In the present study, the net portal fluxes of glucose, lactate, volatile fatty acids (VFA) and amino acids were measured for diets in cluding 650 g maize starch or pea starch/kg. The diets were fed at a l evel 870 kJ digestible energy/kg(0.75) twice daily (06.00 and 18.00 ho urs) to four female pigs in a crossover design. Portal vein blood flow did not differ between maize and pea starches (1620 and 1484 ml/min r espectively; SED 100; P = 0.23). For maize starch portal glucose Bur w as significantly higher during the first 6h after feeding, was not dif ferent 8h after feeding and was significantly lower thereafter. Net po rtal glucose flux was higher for maize starch than for pea starch (175 9 and 1265 mmol/12h respectively; SED 182; P=0.054). Net portal lactat e flux was not significantly different between maize and pea starches (36.5 and 67.2 mmol/12h respectively; SED 24.1; P=0.27) and net portal VFA flux was lower for maize starch than for pea starch (169 and 218 mmol/12h respectively; SED 18; P=0.054). Net portal fluxes of valine, isoleucine, phenylalanine, tryptophan, arginine, serine, cystine, tyro sine, lysine, histidine and the sum of essential amino acids tended to be or were higher (P<0.1 or P<0.05) and net portal flux of aspartic a cid tended to be Lower for pea starch (P<0.1). It can be concluded tha t, although ileal digestibility of both starches is equal, the rate of appearance of glucose in the portal vein was higher for maize starch, influencing the net portal flux of amino acids.