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Centurion, South Africa

Leeuw K.-J.,Agricultural Research Council | Meissner H.H.,Agricultural Research Council | Henning P.H.,Megastarter Biotech t a MS Biotech | Siebrits F.K.,Tshwane University of Technology | And 2 more authors.
Livestock Science | Year: 2016

Virginiamycin (VIR) and monensin (MON) are included in high concentrate diets to mitigate digestive disturbances and to increase performance of ruminants in intensive systems. Megasphaera elsdenii strain NCIMB 41125 (Me) rapidly utilises lactate in the rumen, thereby controlling ruminal pH and digestive disturbances. Me promotes butyrate and valerate production whereas VIR and MON promote propionate that is gluconeogenic and perceived to be more favourable to performance. The objective of the present study was to determine whether the ratio between VFA proportions is more favourable when VIR or MON is administered together with Me and whether their respective effects on health and performance are additive. Two studies of factorial design were conducted, one in vitro fermentation trial where VIR or MON was incubated in the absence of Me (Me-) or in the presence of Me (Me+), and one in vivo trial with steers where MON or Me was administered alone or together. In the in vitro trial VIR and MON were administered to the fermentation vessels in two concentrations, a low dose (0.125μg/mL) and a high dose (0.375mg/mL). Me was administered at 100μL/40mL, supplying 2.5×105cfu/mL. In the in vivo trial 224 Bonsmara steers were allocated to a finishing diet with 80kg/ton roughage and 224 were allocated to a finishing diet with 20kg/ton roughage. Within each diet 112 steers received MON (MONY) and 112 not (MONN) and 112 steers within each diet were dosed with Me (MeY) and 112 not (MeN). In the in vitro trial VIRMe- and MONMe- decreased gas production, whereas VIRMe+ and MONMe+ increased fermentation. VIRMe- and to a lesser extent MONMe- increased total bacterial counts, a result which was apparently due to stimulation of M. elsdenii numbers as determined by 16R DNA sequencing, although other lactate utilising bacteria could have contributed. Me+ reduced lactate and the reduction was more in VIRMe+ and MONMe+. Fermentation end products in Me+ favoured butyrate and valerate and VIRMe- and especially MONMe-, propionate. VIRMe+ and MONMe+ displayed the median. In the steer trial MONY decreased intake and improved feed conversion efficiency. MONY increased carcass gain and dressing percentage on the 80 kg/ton roughage diet but not the 20kg/ton roughage diet. Rumen score on both diets was improved by MONY and liver score by MONYMeY on the 20kg/ton roughage diet. Carcass weight was improved by MONNMeY on the 20kg/ton roughage diet. Morbidity and mortality were not affected by MONY but were improved in the presence of Me (MeY). In general, the results suggest synergy between MON and Me. © 2015 Elsevier B.V.. Source

Meissner H.H.,Agricultural Research Council | Henning P.H.,Megastarter Biotech t a MS Biotech | Leeuw K.-J.,Agricultural Research Council | Hagg F.M.,Megastarter Biotech t a MS Biotech | And 3 more authors.
Livestock Science | Year: 2014

The efficacy of prominent in-feed antibiotics and direct-fed microbials (DFM) to prevent or mitigate ruminal acidosis and lactate accumulation, in addition to whether their presence will enhance or inhibit Megasphaera elsdenii strain NCIMB 41125 (Me) were studied in vitro. The antibiotics studied were aureomycin+sulfamethazine as AS-700 (AS), terramycin as TM-200 (TM), zinc bacitracin (ZB), flavomycin (FM) and tylosin (TS). The DFM were Bovamine (BM) which contains a propionic bacterium and a lactobacillus, Levucell (LC) which contains a strain of the yeast Saccharomyces cerevisiae and Progut (PG) which contains a hydrolysate of S. cerevisiae. The antibiotics and DFM were introduced alone or in the presence of Me to an in vitro system with fermentation vessels containing a medium that promoted rapid gas production and lactate development. Dose sizes of the antibiotics were chosen to inhibit fermentation by 10-20% or 30-40% and for DFM dose sizes were according to the manufacturers. For Me the dose size was 100μl/40ml containing 2.5×105 colony forming units per ml. Me on average reduced lactate from 20.0mM to 4.89mM, increased VFA production and shifted VFA proportions to more butyrate and valerate (respectively from 5.80 to 16.0mM/100mM and from 0.51 to 4.71mM/100mM). The antibiotics moderately reduced lactate (26.7-16.8mM), and AS, ZB and TS enhanced a VFA proportional shift towards propionate (from 22.6 to 28.7mM/100mM). In the presence of Me lactate was reduced to levels of Me alone and the ratio butyrate to propionate was reduced. None of the antibiotics inhibited the action of Me; on the contrary the interaction was additive. In contrast to the antibiotics and PG, the DFM BM and LC did not affect fermentation resulting in no response with respect to any of the variables measured. PG in the presence of Me apparently enhanced the action of Me, as noticed by an additional increase in butyrate and valerate proportions. © 2014 Elsevier B.V. Source

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