Propionibacterium acidipropionici P1691 and glucogenic precursors improve rumen fermentation of low-quality forage in beef cattle2

Abstract

Cattle grazing dormant western rangelands may have a high ruminal acetate to propionate ratio (A:P) and may have low tissue clearance of acetate. Increasing propionate production could shift this ratio and improve animal performance. In Exp. 1, the effect of Propionibacterium acidipropionici P169 (PA) on forage digestibility and VFA production was evaluated in vitro using 2 substrates: 100% dormant warm-season grass extrusa and 50% sorghum-Sudan hay with 50% ground corn (DM basis). The objective of Exp. 2 was to evaluate the effect of PA or calcium propionate supplementation on digestibility, ruminal fermentation, acetate clearance, and BW change. Twelve 2-yr-old, pregnant Brangus heifers (BW = 416 ± 85 kg) were assigned to 1 of 3 treatments. All cattle were fed a basal ration of Old World Bluestem hay (Bothriochloa ischaemum; 5.8% CP and 76.5% NDF, DM basis) at 1.5% BW from d -10 to d 49. Treatments included a protein supplement (CON; 36% CP and 35% RUP, DM basis; 454 g/animal fed twice daily), CON plus 6 × 10(10) cfu PA/animal (BACT), and CON plus 80 g calcium propionate (PROP). After initiation of treatments (d 0), rumen fluid was collected via oral lavage every 3 d and analyzed for VFA, pH, and ammonia. Glucogenic potential of treatments was evaluated with an acetate tolerance test on d 49. In Exp. 1, PA addition increased (IVDMD; P < 0.001) and total VFA (P < 0.001) of 100% dormant warm-season grass extrusa but not 50% sorghum-Sudan hay with 50% ground corn (P ≥ 0.28). The addition of P169 decreased (P < 0.001) acetate, increased propionate (P < 0.001), and decreased A:P ratio (P < 0.001) for both substrates. In Exp. 2, total tract OM and NDF digestibility and ruminal pH, total VFA, and acetate did not differ (P ≥ 0.13) among treatments. Propionate concentration was least (P = 0.001) for CON, intermediate for P169, and greatest for PROP. Conversely, A:P ratio was greatest (P < 0.004) for CON, intermediate for P169, and least for PROP. Acetate clearance did not differ (P = 0.69) among treatments. Propionibacterium acidipropionici P169 increased IVDMD and total VFA of low-quality forage. Supplementation with PA and calcium propionate salts increased propionate and decreased A:P in the rumen. Supplementation of PA represents a potential way to increase ruminal propionate concentration when dormant forages are fed.

The effect of calcium propionate on the ruminal bacterial community composition in finishing bulls

“…In agreement with our results, no differences in ruminal pH were observed in ruminant fed feedlot or other mixed rations with propionate supplementation [8,9]. And there were also no differences detected in pH in steers with a low quality forage based diet [5]. In agreement with our results, no differences in ruminal ammonia concentrations were observed in beef cattle fed feedlot or low quality forage [5,6], which is consistent with the similar bacterial community between the treatments.…”

“…The diet differences between the studies may be the fundamental factor for the variability of propionate concentration. Propionate salt supplementation could probably increase propionate concentration in forage based diets, such as heifers receiving a basal ration of chopped hay [5] or steers consuming rations containing 60% maize stover [6], while there was no effect on a concentrate based diet [9]. In agreement with our results, no differences in ruminal pH were observed in ruminant fed feedlot or other mixed rations with propionate supplementation [8,9].…”

“…Previous studies also showed that addition of sodium or calcium propionate salt could impact ruminant performance [6,18–21]. Supplementing with calcium propionate salts has increased propionate and decreased A:P ratio in the rumen of beef cattle and sheep [5,6,8]. While in our present study, no differences were detected in rumen fermentation parameters between the treatments, including propionate concentration.…”

“…To date, most reports of propionate salt supplementation in ruminant diets focused on performance, such as dry matter digestibility [4–7], carcass index [8,9], and milk and protein yield [7,10,11]. In ruminants, calcium propionate supplementation increased the concentration of propionate in the rumen [5,6,8]. Providing propionate to ruminants may influence microbial dynamics due to the changing of the propionate concentrate in the rumen.…”

SupplementingPropionibacterium acidipropioniciP169 does not affect methane production or volatile fatty acid profiles of different diets inin vitrorumen cultures from heifers

“…We have confirmed a lack of impact on VFA profiles in another study, where we showed no effect of supplementing P169 on propionate or total VFA concentrations in steers (Narvaez et al, 2014), an outcome that may reflect the lack of survival of P169 in the rumen. However, a recent study (Sanchez et al, 2014) showed that supplementing P169 resulted in an increase in propionate and A:P ratio and a decrease in acetate. The discrepancy among studies might be due to differences in adaptability of P169 within the rumen environment, which may arise from the influence of the host or diet.…”