Effect of Lasalocid or Monensin on Lactate-Producing or Using Rumen Bacteria

Abstract

Lasalocid or monensin inhibited most of the lactate-producing rumen bacteria (Butyrivibrio fibrisolvens, Eubacterium cellulosolvens, E. ruminantium, Lachnospira multiparus, Lactobacillus ruminis, L. vitulinus, Ruminococcus albus, R. flavefaciens, Streptococcus bovis). Minimum inhibitory concentrations ranged from .38 to 3.0 micrograms/ml. Among the lactate producers, those that produce succinate as a major end product (Bacteroides, Selenomonas, Succinimonas, Succinivibrio) were not inhibited by lasalocid or monensin. Also, none of the major lactate fermenters (Anaerovibrio, Megasphaera, Selenomonas) was inhibited by lasalocid or monensin. Veillonella alcalescens was inhibited by 24 micrograms/ml of lasalocid but was resistant to monensin. Hence, the reported increase in propionate in lasalocid- or monensin-fed cattle may result from selection for succinate producers and lactate fermenters. Lasalocid and monensin appeared to inhibit selectively the production of L(+), but not D(-) lactic acid. The inhibition of major lactate-producing bacteria (Streptococcus and Lactobacillus) suggests that lasalocid or monensin may be used to prevent lactic acidosis in ruminants.

Metabolismo oxidativo dos neutrófilos de ovinos tratados com monensina sódica e experimentalmente submetidos à acidose ruminal

“…Tal alteração coincide com a diminuição na concentração do ácido láctico no fluido ruminal dos ovinos que receberam o antibiótico, a partir das 24h pós-indução, nos quais os valores foram inferiores de forma significativa (p<0,05), quando comparado ao grupo controle. Acreditamos que devido à característica inibitória que tem este ionóforo sobre a microbiota Gram-positiva, principal produtora do ácido láctico e conseqüente responsável pela diminuição do pH, tenha contribuído para este resultado favorável (Chen & Wolin 1979, Dennis et al 1981. Não ocorreu diferença estatística significativa (p>0,05) nos valores de neutrófilos positivos, na prova de redução do NBT, determinados em ambos os grupos, e nem entre os respectivos momentos de cada um dos grupos; entretanto, em ambos os grupos ocorreu uma diminuição de aproximadamente 50% de neutrófilos NBT-positivos 6 horas após a indução da acidose, assim que a recuperação dos valores do pH ruminal e sangüíneo não implicou no restabelecimento da capacidade dos neutrófilos do grupo controle reduzirem o NBT (Quadro 1, Fig.…”

Sodium monensin or propolis extract in the diet of crossbred (½ Red Angus vs. ½ Nellore) bulls finished in feedlot: chemical composition and fatty acid profile of the Longissimus muscle

“…The primary action of the monensin appears to take place in the rumen. Monensin's modes of action rely on the selective growth inhibition of gram-positive bacteria (VAN NEVEL;DEMEYER, 1988), reducing lactic acid production (DENNIS; NAGARAJA; BARTLEY, 1981) and methanogenesis in the rumen (GOODRICH et al, 1984) and increasing the molar proportion of propionate (GOODRICH et al, 1984) and N retention. The positive production responses of livestock to dietary monensin supplementation have been well-documented, e.g., the improvement of feed conversion, particularly in high-grain diets (BOUCQUÉ et al, 1982;OLIVEIRA et al, 2006).…”

Effect of Monensin on Production of Volatile Fatty Acids from Cellulose, Hemicelluloses, Pectin and Starch in Mixed Cultures of Rumen Microorganisms

“…Our results support opinion of those authors who found that monensin depressed the fermentation of fiber and cellulose. The depression of fiber digestion can be reasonably explained by the inhibitory effect of monensin on rumen cellulolytic bacteria, mainly ruminococci and butyrivibria (Dennis et al 1981;Henderson et al 1981). As it is known that monensin increases the productive efficiency of ruminants on both high-concentrate (review Galyean and Owens 1988) and roughage diets (Potter et al 1976;Faulkner et al 1985), we must assume that unfavourable effect of monensin on digestion of cellulose is compensated for by its benefitial effect on digestion of other components of plant matter and/or by increased post-ruminal cellulose digestion.…”