LACTIC ACID BACTERIA AS INOCULANTS FOR CORN (Zea mays) SILAGES USED TO FEED FEEDLOT STEERS

NATALIA CECILIA MALDONADO; DAVID UEZEN; GRACIELA VIGNOLO; MARIA ELENA FÁTIMA NADER; FERNANDO DI LUCCA; MARIA INES ISLA

San Miguel de Tucuman

Simposio; V INTERNATIONAL SYMPOSIUM ON LACTIC ACID BACTERIA. Benefitting from Lactic Acid Bacteria Progress in Health and Food; 2016

CERELA

LACTIC ACID BACTERIA AS INOCULANTS FOR CORN (Zea mays)SILAGES USED TO FEED FEEDLOT STEERSF. J. Di Luca, D. Uezen, N. Maldonado, M.I. Isla, F. Nader, G. VignoloCentro de Referencia para Lactobacilos (CERELA-CONICET). Chacabuco 145. (4000) -Tucumán- Argentina, and Instituto de Química del Noroeste Argentino (INQUINOA-CONICET). vignolo@cerela.org.arEnsiling is a preservation method for moist forage crops. It is based on lactic acid bacteria(LAB) converting water-soluble carbohydrates (WSCs) into organic acids, (lactic and aceticacids), under anaerobic conditions. As a result, pH decrease and moist forage is preservedfrom spoilage microorganisms. Corn (Zea mays) silage is the most commonly used infeedlot-steers diets and is often inoculated in an effort to improve their preservation andquality. In this study, the performance of LAB strains inoculated in whole-crop corn foragesilage containing 30-35% dry matter (DM), during 45 days-fermentation at 23 ºC wasevaluated. Corn minisilos were individually inoculated with the homolactic Pediococcusacidilactici CRL2043 (LAB-1), heterolactic Lactobacillus fermentum CRL2085 (LAB-2) andwith the two strains combined (LAB-mix) at an initial concentration of 5.0 log CFU/g.Minisilos were sampled at 0, 10, 20, 30 and 45 days after ensiling for microbiological andphysicochemical analysis. Results showed total mesophyle in inoculated silages rangedfrom 6.0 to 7.5 log CFU/g. Although an initial decrease in LAB counts were observed, thispopulation in the inoculated minisilos reached final counts between of 6.5 and 7.2 logCFU/g; those inoculated with P. acidilactici exhibited the lowest numbers. In addition,yeasts and moulds showed a higher growth in silages inoculated with the homolactic LAB-1 compared with samples inoculated with LAB-2 or LAB-mix. During fermentation, pHvalues decreased from 5.8 in fresh corn to around 3.6, P. acidilactici inoculated silageshowing the higher acidifying rate. Physicochemical data during corn silage fermentationindicated DM loss. WSCs and crude protein were not significantly affected by inoculation,while a decrease and increase in starch and neutral detergent fiber concentrations,respectively was observed. When aerobic stability (deterioration upon opening) of silageswas investigated, mixed inoculated showed the lowest DM loss compared to the control,whereas improved aerobic stability was obtained in the presence of L. fermentum withand without P. acidilactici by inhibition of yeast activity. Thus, there is a potential to addboth microorganisms simultaneously to improve the fermentation and aerobic stability ofcorn silage as food for lot steers.Keywords: silage, corn, lactic acid bacteria, fermentationThis work was performed into the CONICET-TRIGOTUC cooperation project