Ciências Agrárias
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/2
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Item Novel lactic acid bacteria strains as inoculant for alfalfa and corn silages and microbiome of rehydrated corn and sorghum grain silages(Universidade Federal de Viçosa, 2019-02-28) Agarussi, Mariele Cristina Nascimento; Pereira, Odilon Gomes; http://lattes.cnpq.br/8860849574906659This study was divided into five chapters Chapter 1 - The experiment was carried out under a completely randomized design with three replicates based on a 6 × 6 factorial arrangement, with 6 inoculants: T1- control (CTRL), T2- commercial inoculant containing Lactobacillus plantarum + Pediococcus pentosaceus (CI), T3- Lactobacillus pentosus 14.7SE (LPE), T4- Lactobacillus plantarum 3.7E (LP), T5- Pediococcus pentosaceus 14.15SE (PP), T6- Lactobacillus plantarum 3.7E + Pediococcus pentosaceus 14.15SE (LP+PP); and six fermentation periods: 1, 3, 7, 14, 28 and 56 days. Alfalfa was wilted for 6 h and increased the dry matter (DM) content to 368 g/kg as fed. The crude protein (CP) and yeast population decreased during the fermentation process. Highest pH decline rates in the first week of fermentation were observed for inoculated silages. Among inoculants, the PP strain resulted in lowest pH values from 14 d of fermentation and lowest acetic acid concentration in the last day of fermentation. Enterobacteria and molds populations were more efficiently controlled by new strains at day 56 and 28, respectively. The in vitro dry matter digestibility was higher in PP than LP silages (64.45 vs. 61.18% DM). Adding of P. pentosaceus alone resulted in positive influence on all evaluated parameters, thus providing better silage quality. Chapter 2 – We evaluated the effects of wild strains of Lactobacillus buchneri on chemical composition, fermentative profile and aerobic stability of corn silages after 90 days of fermentation. The experiment was carried out under a completely randomized design with three replicates and 13 treatments consisted in 1- water (CRTL), 2- commercial L. buchneri strain (CI), and 11 wild strains of L. buchneri: 3- strain 56.1, 4- strain 56.2, 5- strain 56.4, 6- strain 56.7, 7- strain 56.8, 8- strain 56.9, 9- strain 56.21, 10- strain 56.22, 11- strain 56.25, 12- strain 56.26, and 13- strain 56.27. A treatment effect (P < 0.05) was observed on pH, WSC, NH3-N, lactic, acetic and propionic acids, ethanol and 1,2-propanediol concentrations. The lowest pH was observed in CTRL silages, contrary, 56.1, 56.4, and 56.9 silages had the highest values (3.65 vs. 3.84). CTRL silages had higher residual WSC than CI, 56.2 and 56.7 silages and higher lactic acid concentration than CI and 56.4. The lowest NH3-N concentrations were observed in 56.1 and 56.7 silages conversely the highest concentrations were found in 56.8 and 56.21 (7.11 vs. 10.01% of total nitrogen). Inoculated silages with 56.1 strain had the highest acetic and propionic acids concentrations and higher ethanol production than CI, 56.7, 56.9, 56.22, 56.25, and 56.26 silages. The populations of enterobacteria and yeasts & molds, DM, CP, neutral detergent fiber, acid detergent fiber contents and DM recovery after 90 d of fermentation were not affected (P > 0.05) by treatment. Silage treated with 56.1 strain had higher aerobic stability than non-inoculated silages (68.25 vs. 36 h). The L. buchneri strain 56.1 has the potential to be used as microbial inoculant in corn silage. Chapters 3 and 4 - We explored the succession of bacterial and fungal populations, and evaluated the impacts caused by Lactobacillus plantarum + Propionibacterium acidipropionici and Lactobacillus buchneri inoculants on those communities of rehydrated corn and sorghum grains and their silages by next-generation sequencing after 0, 3, 7, 21, 90 and 360 days of fermentation. Proteobacteria was predominantly in both grains at the beginning of the fermentation and Firmicutes phylum throughout the fermentation periods. Species of Lactobacillus and Weissella were the main bacteria involved in the fermentation of rehydrated corn and sorghum grain silages. Aspergillus spp. molds were predominant in corn grain fermentation while the yeast Wickerhamomyces anomalus was the major fungal in sorghum grain silages. The inoculant containing L. plantarum and P. acidipropionici was more efficient in promoting a sharply growth of Lactobacillus spp. and maintaining greater stability of the bacterial community during longer periods of storage in both grains silages. The addition of inoculant did not have an influencial effect on fungal population of rehydrated sorghum grain silages. Chapter 5 - It was evaluated the effect of ensiling on the fermentation profile, corn silage processing score (CSPS) and long-chain fatty acids (LCFA) profile of whole-plant corn. Eleven corn hybrids were obtained at harvest. Each of the 11 samples was homogenized manually and allocated into 4 samples of approximately 600 g each. Each of the 4 samples was randomly assigned to 1 of 2 treatments (0 or 120 d of ensiling) and vacuum-sealed in nylon-polyethylene standard barrier vacuum pouches. Concentration of DM was unaffected (P > 0.10) by ensiling and averaged 36.2% as fed. The effects on pH is likely attributed to 7.7%-, 1.0%- and 1.2%-units greater (P < 0.02) lactic, acetic and isobutyric acids concentrations, respectively, for 120 d compared with 0 d. Concentrations of NH3-N increased (P = 0.001) with ensiling, as expected. Starch concentrations and CSPS was unaffected (P > 0.10) by ensiling and averaged 31.2% of DM and 28.8%, respectively. No effects of ensiling were observed on LCFA profile of major FA including C16:0, C18:0, C18:1, C18:2, and C18:3 FA (P > 0.10). Further research is warranted to elucidate under which conditions ensiling time enhances the CSPS.Item Efeito de emurchecimento e de inoculante bacteriano sobre a população microbiana e perfil fermentativo em silagem de alfafa em condições tropicais(Universidade Federal de Viçosa, 2015-02-24) Agarussi, Mariele Cristina Nascimento; Pereira, Odilon Gomes; http://lattes.cnpq.br/8860849574906659Avaliou-se o perfil fermentativo, a composição química e as populações microbianas de silagens de alfafa emurchecida ou não, tratadas com inoculante bacteriano em diferentes períodos de fermentação; bem como o isolamento, a identificação e a caracterização das bactérias do ácido lático (BAL) das silagens não inoculadas. Foi utilizado um esquema fatorial 2 × 2 × 6, ausência ou presença de emurchecimento (E), com e sem inoculante bacteriano (I) e seis períodos de fermentação (P) (1, 3, 7, 14, 28 e 56 dias), no delineamento inteiramente casualizado, com três repetições. A alfafa foi colhida aos 50 dias de rebrotação e picada em partículas de 1,5 cm. A alfafa foi emurchecida por 6h, no campo, no material submetido a esse tratamento. O inoculante usado foi o Sil-All® 4x4 W.S. (Alltech, Brasil), aplicado na taxa de 10 5 UFC/g (5 g/t de forragem). Após a aplicação dos tratamentos, a forragem foi ensilada em sacos plásticos de 25 × 35 cm e selados a vácuo. O emurchecimento da alfafa reduziu a capacidade tampão e as concentrações de carboidratos solúveis em água e aumentou o teor de MS da forragem de 133,9 g/kg MS para 233,4 g/kg MS, antes da ensilagem. Foi observado efeito (P < 0,05) de E sobre os teores de MS, PB, NIDA e FDN das silagens aos 56 dias de fermentação. As populações de BAL e fungos não foram afetadas por nenhum dos fatores estudados, enquanto as populações de enterobactérias e leveduras foram afetadas (P < 0,05) pelo P. O pH e a concentração de nitrogênio amoniacal foram afetados (P < 0,05) pela interação E × P, registrando-se menores valores destas variáveis nas silagens emurchecidas. Também foi observado efeito (P < 0,05) da interação E × P sobre o conteúdo dos ácidos lático, acético e propiônico, sendo registrados menores valores de ácido acético nas silagens emurchecidas em todos os períodos de fermentação. Menores concentrações de ácido propiônico também foram encontradas nas silagens emurchecidas. Excetuando o 1o dia de fermentação, foram observadas maiores concentrações de ácido lático nas silagens emurchecidas, no entanto, a partir do 7o dia, a concentração deste ácido decresceu em ambas as silagens emurchecidas ou não. A adição de inoculante bacteriano na presença ou não do emurchecimento, não promove melhorias no x processo fermentativo de silagem de alfafa com elevada umidade. A população de BAL na planta e nas silagens de alfafa submetidas ou não ao emurchecimento é diversa em nível de espécies, o Lactobacillus plantarum é a espécie predominante e apresenta comportamento distinto ao longo dos períodos de fermentação nas silagens não emurchecidas e emurchecidas.