Effect of sodium bicarbonate and glucose on ruminal fermentation, acid-base balance and blood chemistry in sheep

The effects of NaHCO3 and glucose on ruminal fermentation, acid-base balance and blood chemistry were assessed in sheep fed with 60% of concentrated. Four ruminally cannulated sheep (65 +/- 10 kg initial BW) were used in a cross-over design in metabolic crates. Sheep were fed with a total mixed ration (concentrate 60% and forage 40%). Each period included adaptation of 14 d and 2 d of sample collection. Glucose (1 g on day 1, and 2 g glucose/kg BW on day 2) was ruminally administrated to all the animals. Treatments consisted of 20 g/d of NaHCO3 in the feeding and a control. Dry matter intake was measured daily. Ruminal fluid samples were collected at 0, 2, 4 and 6 h to determine pH, VFA, L-lactate, osmolality and protozoa. Blood samples were collected at 0 and 6 h to determine pH, HCO3, PCO2, base excess, electrolytes (Na, K, Cl), anion gap and other metabolites. Sheep receiving NaHCO3 had highest VFA concentration with more proportion of acetate and less propionate; and increased nutrient intake (DM, protein, NDF y starch) (P < 0.05). Acid-base balance and electrolytes were not affected by treatments (P > 0.05). The principal effect of NaHCO3 was to increase acetate without changes in the acid-base and electrolytes balance, with limited effects on ruminal fermentation and blood chemistry in the sheep.