Banca de DEFESA: LILIANE PEREIRA SANTANA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LILIANE PEREIRA SANTANA
DATE: 30/04/2025
TIME: 14:00
LOCAL: Online, plataforma Meet, link meet.google.com/zcf-njmr-jcv
TITLE:

PEAR MILLET CULTURE: AGRONOMIC ASPECTS, LACTIC BACTERIA AND THEIR USE AS INOCULANT IN SILAGE

KEY WORDS:

Microbial inoculants, Aerobic stability, Nitrogen fertilization, Microbial population, Storage period.

PAGES: 102
BIG AREA: Ciências Agrárias
AREA: Zootecnia
SUBÁREA: Pastagem e Forragicultura
SPECIALTY: Avaliação, Produção e Conservação de Forragens
SUMMARY:

Divided into four chapters, this thesis work was carried out to investigate the agronomic aspects, lactic acid bacteria and their use as inoculant in millet silage. Chapter 1 presents a literature review on millet cultivation, addressing agronomic aspects and aspects related to its use in the form of silage. Chapter 2 is a systematic review on the impact of homo- and heterofermentative bacteria on the aerobic stability of silages. The review revealed that inoculants containing heterofermentative strains, such as Lactobacillus buchneri and Lactobacillus hilgardii, are highly effective in reducing aerobic deterioration of silage. These bacteria promote the production of acids with antifungal action, which results in greater aerobic stability of silage. In contrast, homofermentative inoculants are still widely used, especially in forages with low water-soluble carbohydrate content, playing a crucial role in initial fermentation and reducing gas losses. Chapter 3 consists of a scientific article addressing the effects of different nitrogen fertilization rates (0.50, 100 and 150 kg of N ha) on productivity, morphometric characteristics and bromatological composition of millet. It was observed that increasing nitrogen rates promote significant improvements in productivity, morphometric characteristics and bromatological composition of the forage produced. Increasing the nitrogen rate resulted in an increase in crude protein (CP) contents, dry matter accumulation (DMA) and plant height. The 82 kg/ha nitrogen rate promoted maximum dry matter content, while CP contents ranged from 7.44 g/kg DM (without N application) to 13.40 g/kg DM (150 kg N/ha). The quadratic response of dry matter accumulation (DMA) showed an increase in the averages from 2.48 (without N) to 5.55 t/ha of DM (100 kg N/ha). The maximum values of plant height and leaf length (1.91 and 10.12 cm) were observed for doses of 92 and 91 kg/ha of N, respectively. The most promising results were observed in the range between 50 and 100 kg/ha of N. In chapter 4, the objective was to evaluate the quality of millet silages based on the application of different microbial inoculants, over different fermentation periods (15, 45, 90 and 180 days). The results indicated that the dry matter content was significantly influenced by the inoculants and the fermentation period. The silage with Lactobacillus plantarum showed the highest DM content at 15 days (22.17 g/kg MN), while the highest average values were observed in silages with L. plantarum, control and L. buchneri, at 180 days. CP contents were higher in silages with L. plantarum and L. buchneri at 45 days (9.62 and 9.60 g/kg DM, respectively). Silages with L. plantarum and Weissella cibaria showed lower neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents, especially at 45 and 180 days for both variables. The pH of the silages was influenced by the inoculants, with the highest average value recorded in silage with L. buchneri (4.06). The concentration of soluble carbohydrates varied throughout the fermentation time, being higher (62.8 g/kg DM) in silages inoculated with L. plantarum + W. cibaria at 90 days. The population of lactic acid bacteria was affected by the type of inoculant and fermentation period, with L. buchneri and W. cibaria demonstrating antimicrobial effects. Lactic acid production was higher in silages inoculated with L. plantarum, W. cibaria and L. plantarum + W. cibaria, while acetic acid production was more significant in silages inoculated with L. buchneri. Effluent losses were lower in silages treated with L. plantarum and L. buchneri, while gas losses were higher in silages treated with W. cibaria, especially at 180 days. Dry matter recovery was higher in silage inoculated with L. buchneri (78.25 g/kg DM) and inversely proportional to fermentation losses. Aerobic stability was significantly higher for silages treated with L. buchneri, particularly at 180 days (110 hours). Therefore, according to the results of the chapters of this thesis, it was possible to conclude that: Studies indicate a growing trend in the use of inoculants in silage, with emphasis on heterofermentative bacteria, which promote greater aerobic stability. Their use on farms can improve silage conservation and reduce losses. Nitrogen fertilization improves the morphometric, bromatological and productive characteristics of millet. The application of up to 100 kg/ha of N with urea provided greater accumulation of dry matter, increased crude protein content and maintenance of fiber levels, balancing productivity and nutritional quality of the forage. The use of inoculants such as L. buchneri, W. cibaria and the combination of L. plantarum + W. cibaria significantly improved the fermentation profile of millet silage, controlled pH, reduced fungi and yeasts, increased dry matter recovery and acetic acid production, and increased aerobic stability. The addition of L. plantarum was effective in maintaining dry matter content and reducing fermentation losses. A longer fermentation period resulted in increased pH, reduced fungi and yeasts, lower dry matter recovery and greater aerobic stability. Thus, the type of inoculant and fermentation time are key factors in the quality of millet silage.

COMMITTEE MEMBERS:
Presidente - ALEXANDRE CARNEIRO LEAO DE MELLO
Interno - MARCIO VIEIRA DA CUNHA
Interno - VALDSON JOSE DA SILVA
Externo à Instituição - EDSON MAURO SANTOS - UFPB
Externo à Instituição - JOSÉ NILDO TABOSA