The Effect of Commercial Additive (Toxic-Chec) and Propionic Acid on the Fermentation and Aerobic Stability of Silage with Pig Excreta
Serafin J. López-Garrido *
Animal Science Department, Universidad del Mar Campus Puerto Escondido, Puerto Escondido, Oaxaca, México.
Mario A. Cobos Peralta
Animal Housbandry Program Colegio de Postgraduados, Campus Montecillo, Texcoco, México.
Germán D. Mendoza Martinez
Veterinary and Animal Production Department, Universidad Autónoma Metropolitana, Unidad Xochimilco, D.F. México.
Marco A. Camacho-Escobar Camacho-Escobar
Animal Science Department, Universidad del Mar Campus Puerto Escondido, Puerto Escondido, Oaxaca, México.
*Author to whom correspondence should be addressed.
Abstract
The experiment was carried out to evaluate the effect of Toxic-chec commercial additive and propionic acid on the fermentation and aerobic Stability of silage made with pig excreta, corn stover, molasses and urea; during fermentation. The growth of microorganisms in the silage and aerobic stability of the silage were tested. Microsilos were conducted in the laboratory with the following treatments made in triplicate (T): T1 = silage without additive; T2 = silage + 0.05% commercial additive; T3 = silage + 0.05% propionic acid. Three microsilos were realized by treatment in a complete randomized design. The study was carried out in the laboratories of Rumen Microbiology and Animal Nutrition, Graduate College, Montecillo State Campus, Mexico, between June and November 2012. The results showed that the additives tested affected the pH in treatments, but did not affect the concentration of volatile fatty acids, acetic, propionic and butyric acid, and ammonia nitrogen. To evaluate the aerobic stability of the silages with treatments upon exposure to the presence of air for 16 days and the concentration of microorganisms in colony forming units per gram of silage was characterized. The additives tested did not avoid the decrease in the concentration of lactic acid bacteria and lactobacilli (P<0.05) between 8 and 16 days; in contrast, lactobacilli disappeared completely by 16 days in T1, maintaining a low concentration in T2 and T3. Enterobacteriae concentration was not affected by additives tested; yeast concentration decreased (P<0.05) between treatments, being more evident at day 16. Results suggest that the additives tested did not affect the fermentation to maintain viable populations of lactic acid bacteria and lactobacilli, and decreasing the concentration of yeast potentiate aerobic stability and preventing aerobic deterioration of silage pig excreta.
Keywords: Silage, pig excreta, fermentation, volatile fatty acids, aerobic spoilage, stability of anaerobic fermentation