Dietary protein restriction and fat supplementation diminish the acidogenic effect of exercise during repeated sprints in horses

A restricted protein diet supplemented with amino acids and fat may reduce the acidogenic effects of exercise, Twelve Arabian horses were assigned to a 2 x 2 factorial experiment: two fat levels: 0 or 10 g/100 g added corn oi l and two crude protein levels: 7.5 g/100 g (supplemented with 0.5% L-lysin e and 0.3% L-threonine) or 14.5 g/100 g, The experiment began with a 4-wk d iet accommodation period followed by a standard exercise test consisting of six 1-minute sprints at 7 m/s. Horses were interval trained for 11 wk foll owed by another exercise test with sprints at 10 m/s. Blood samples were ta ken at rest and during the exercise tests. Plasma was analyzed for PCO2, PO 2, Na+, K+, CI-, lactate, pH and total protein. Bicarbonate, strong ion dif ference and total weak acids were calculated. Data were analyzed using repe ated-measures analysis of variance. Venous pH was higher in the low protein group during the first test (P = 0.0056) and strong ion difference became higher (P = 0.022) during sprints in the low protein group. During the seco nd test, venous pH and bicarbonate were higher for the low protein high fat group (P = 0.022 and P = 0.043, respectively) and strong ion difference be came higher (P = 0.038) at the end of exercise in the low protein groups. T hese results show that restriction of dietary protein diminishes the acidog enic effect of exercise, especially in combination with fat adaptation.