Effect of acarbose on acute acidosis

Abstract

A challenge model was used to evaluate a new approach to controlling acute acidosis. Acute acidosis reduces performance in both dairy and beef cattle and most often occurs as a consequence of ingestion of large amounts of readily fermentable starch, resulting in increased production of volatile fatty acids (VFA) and lactic acid and a reduction in ruminal pH. Acarbose is an alpha-amylase and glucosidase inhibitor that slows the rate of degradation of starch to glucose, thereby reducing the rate of VFA production and maintaining rumen pH at a more stable level. It is commercially available (Glucobay, Bayer, Wuppertal, Germany) and indicated for the control of blood glucose in diabetic patients. The ability of acarbose to reduce the incidence of acidosis and the comparative efficacies of acarbose, sodium bicarbonate, and monensin were tested in 3 acute acidosis challenge experiments in cattle. Rumen-cannulated Holstein steers were challenged with a mixture of 48.4% cornstarch, 48.4% ground corn, 2.1% sodium caseinate, and 1.1% urea with or without test substance. The challenge was administered at a rate of 12.5 g/kg of body weight (BW) as a slurry through the cannula directly into the rumen. Ruminal pH was monitored at 10-min intervals throughout the study. Animals were removed from study and rumen contents replaced if they exhibited acute acidosis as defined as pH <4.5. If acidosis was not observed within 24 h, animals were subjected to a second challenge. Ruminal fluid samples were taken for measurement of VFA and lactate concentrations at various intervals after the challenge. In experiment 1, the carbohydrate challenge induced acidosis in 4 of 4 control animals and 0 of 4 animals treated with 2.14 or 21.4 mg of acarbose/kg of BW in the challenge based on the criterion of pH <4.5. In experiment 2, the carbohydrate challenge induced acidosis in 4 of 7 control animals and 1 of 7 animals when 1.07 mg of acarbose/kg of BW was included in the challenge. In experiment 3, acidosis was induced in 7 of 7 animals in the control, 1% sodium bicarbonate, and 12 mg of monensin/kg of dry matter intake groups and in 3 of 8 steers administered 1.07 mg of acarbose/kg of BW in the challenge. Increases in lactate concentrations and decreases in total VFA associated with acute acidosis were mitigated by acarbose. Thus, acarbose, an amylase and glucosidase inhibitor, prevented or reduced the incidence of acidosis in an acute challenge model in steers and was more effective than monensin or sodium bicarbonate.

Effects of Carbohydrase-Inhibiting Compounds onin VitroRumen Fermentation

“…Starch disappearance at the dose of 150 mg, resulted the lowest for BBE followed by CFL and WMB, and finally by PHA that led to the highest value. As previously reported by other authors (McLaughlin et al, 2009a(McLaughlin et al, , 2009bSpeight and Harmon, 2010), ACB successfully prevented the production of excessive amounts of VFA, which are primarily responsible for the onset of subacute ruminal acidosis in cattle Marchesini et al, 2013) and consequently countered the drop of ruminal fluid pH. This effect was likely due to the inhibitory activity of ACB towards -glycosidase and -amylase Within incubation time, different lowercase superscripts in the same row denote significant differences (P<0.05) with a dose of 15 or 150 mg.…”

“…*P<0.05; **P<0.01; ***P<0.001; ns, not significant. produced by ruminal microorganisms (McLaughlin et al, 2009a(McLaughlin et al, , 2009bSpeight and Harmon, 2010). Such activity contributed in the reduction of the fermentation of maize starch and sugars compared to other supplements and Control after both 5 and 24 h of incubation.…”

“…Bilberry (Vaccinium myrtillus) extract (BBE) was selected because it is rich in anthocyanins (Chu et al, 2011), which are phenolic compounds that have shown potential for reducing hyperglycaemia in humans (Zunino, 2009) and demonstrated inhibitory activity against -amylase and -glucosidase (Johnson et al, 2011). Acarbose was chosen as a positive control because it was found to be effective in reducing ruminal fermentation of cereal grains in both in vitro (Speight and Harmon, 2010) and in vivo (McLaughlin et al, 2009a(McLaughlin et al, , 2009b studies.…”

“…As demonstrated for acarbose by McLaughlin et al (2009aMcLaughlin et al ( , 2009b, dietary carbohydrase inhibitors can benefit cattle and dairy cows fed high-grain diets by preventing the onset of ruminal acidosis. These inhibitors can slow the fermentation of starch, consequently preventing the rapid drop in ruminal pH, especially in the first 5 h after the meal (Nordlund and Garret, 1994) and precluding the economic losses associated with ruminal acidosis (Krause and Oetzel, 2005).…”

“…Over the last 10 years of human medical and animal nutrition research, a number of studies have focused on the use of -amylase andglucosidase inhibitors to manage disorders of carbohydrate metabolism, such as type 2 diabetes and ruminal acidosis (Bischoff, 1994(Bischoff, , 1995Martin and Montgomery, 1996;McLaughlin et al, 2009aMcLaughlin et al, , 2009b. These supplements have been shown to reduce the degradation of starch and the absorption of glucose in the proximal portions of the small intestine, thereby lowering the post-prandial serum glucose levels (Tarling et al, 2008).…”