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 oil and two crude protein levels: 7.5 g/100 g (supplemented with 0.5% L-lysine and 0.3% L-threonine) or 14.5 g/100 g. The experiment began with a 4-wk diet 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 followed by another exercise test with sprints at 10 m/s. Blood samples were taken at rest and during the exercise tests. Plasma was analyzed for PCO(2), PO(2), Na(+), K(+), Cl(-), lactate, pH and total protein. Bicarbonate, strong ion difference and total weak acids were calculated. Data were analyzed using repeated-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 second 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 became higher (P = 0.038) at the end of exercise in the low protein groups. These results show that restriction of dietary protein diminishes the acidogenic effect of exercise, especially in combination with fat adaptation.
Graham-Thiers
P M
PM
Virginia Polytechnic Institute and State University, Blacksburg, VA 24601-0606, USA. thiers@3wave.com
Kronfeld
D S
DS
Kline
K A
KA
Sklan
D J
DJ
D000136:Acid-Base Equilibrium; D000220:Adaptation, Biological; D000704:Analysis of Variance; D000821:Animal Feed; D000818:Animals; D001639:Bicarbonates / Q000097:blood; D001784:Blood Gas Analysis; D018753:Diet, Protein-Restricted / Q000662:veterinary; D004041:Dietary Fats / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage*; D005080:Exercise Test / Q000662:veterinary; D005260:Female; D006734:Horse Diseases / Q000517:prevention & control*; D006736:Horses / Q000378:metabolism / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000097:blood; D008297:Male; D010100:Oxygen / Q000097:blood; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011488:Protein Deficiency / Q000517:prevention & control / Q000662:veterinary*
D001639:Bicarbonates; D004041:Dietary Fats; D004044:Dietary Proteins; D019344:Lactic Acid; D010100:Oxygen