Quantificação e caracterização dos compostos ativos da própolis e seus efeitos sobre a nutrição e qualidade do leite de vacas e cepas bacterianas do rúmen

• Autor(a) principal: Aguiar, Sílvia Cristina de
• Data de Publicação: 2012
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/1615
• topic: Aditivo; Atividade bacteriana; CLA; Extrato de própolis; Flovonóides; Oxidação lipídica; Bovino de leite; Qualidade do leite; Nutrição animal; Microrganismos do rúmen; Brasil.; Additive; Bacterial activity; CLA; Propolis extract; Flovonóides; Lipid oxidation; Bovine milk; Milk quality; Animal Nutrition; Microorganisms in the rumen; Brazil.; Ciências Agrárias; Zootecnia

Five experiments were carried out in order to quantify the phenolic compounds present in different propolis-based products (LLOS) and study its effects on digestibility, ruminal and blood parameters and efficiency microbial protein synthesis in dairy cows, and assess their effects on fatty acids composition (FA) and antioxidant capacity in milk produced by these cows. Also, the antimicrobial activity of propolis extracts on ruminal bacterial strains was evaluated.The first experiment aimed to develop and validate a method for separation and quantification of phenolic compounds in twelve propolis extracts obtained by different extraction conditions using HPLC. For validation, we analyzed the linearity, precision (repeatability, intermediate precision and reproducibility), limit of detection and quantification, recovery/accuracy and stability of the analyte. The developed method was validated providing certainty in the quantification of total flavonoids and phenolic acids present in different propolis extracts. The different concentrations of propolis and alcohol levels interfere in the extraction of the active compounds of propolis, which may change its chemical composition and biological properties. In the second experiment, the objective was to obtain a phenolic fingerprint of propolis extracts using HPLC. Regarding the phenolic acids, four compounds were identified in the twelve extracts (caffeic acid, p-coumaric acid, CAPE and Artepillin C), while some compounds were detected only in some extracts (gallic acid, chlorogenic acid). For flavonoids, apigenin, pinocembrin, and chrysin were detected in all extracts and galangin and acacetin were detected in most extracts; however naringenin has been identified only in two extracts. The different concentrations of propolis and alcohol levels directly influence the extraction of some phenolic compounds, which alters the chemical composition of the propolis extracts. In the third experiment, propolis-based products (LLOS) were evaluated, in order to estimate the feed intake, total, (TD), ruminal (RD) and intestinal (ID) digestibility, pH nd ruminal ammonia-nitrogen production (NH3-N), rumen microbial synthesis and blood parameters. Four Holstein cows, weighing 550 ± 34.16 kg of BW and cannulated in the rumen were used, and distributed in a 4 x 4 Latin Square. The diet contained 59.19% of corn silage and 40.81% of concentrate, differing with the addition or not of LLOS: control (no LLOS), LLOS B1, LLOS C1 and LLOS C3. The ruminal pH, efficiency of microbial protein synthesis and blood parameters were not affected (P> 0.05) by the addition of LLOS, but there was an effect of the propolis-based products (P <0.05) on feed intake, TD, RD, ID and NH3-N production. The LLOS provided lower (P <0.05) RD of CP, the LLOS C1 reduced the ruminal NH3-N production and the LLOS B1 increased the ID of the CP compared to the control diet. The addition of the LLOS products interfere with ruminal metabolism and the product LLOS C1 had a positive effect on nitrogen metabolism, because it reduced the losses of N in the NH3 form, in the rumen. In the fourth experiment, the effects of the LLOS were evaluated on the quality, fatty acid (FA) composition and antioxidant capacity in milk samples from cows in the previous experiment. The LLOS did not affect (P> 0.05) the quality and somatic cell count of milk samples. It was observed an inversion in the milk fat and protein contents in all treatments, which was probably due to the addition of soybean oil to diet. The addition of propolis affected (P <0.05) the FA composition and increased the antioxidant capacity of milk. At the lowest concentration of flavonoids there was an increase (P <0.05) in total polyunsaturated and monounsaturated FA, with reduction in the total saturated FA. At the highest concentration of flavonoids, there was a higher content of the cis-9,trans-11 isomer (CLA) compared to the other treatments, followed by the intermediate concentration of flavonoids in the products. The addition of LLOS to diet reduced the n-6/n-3 ratio when compared to control diet. For all LLOS, there was an increase (P <0.05) in the antioxidant capacity of cows, since improve animal performance and the milk quality from dairy cows; however, more studies are needed tobetter understanding of its antimicrobial activity milk in relation to control diet. In the fifth experiment, the antimicrobial activity the propolis extracts was evaluated on rumen bacterial strains. The different propolis extracts inhibited the growth of Fibrobacter succinogenes, Ruminococcus flavefaciens, R. albus 7, Butyrivibrio fibrisolvens, Prevotella albensis, P. ruminicola, Peptostreptococcus sp., Clostridium aminophilum and Streptococcus bovis, while R. albus 20, P. bryantii and Ruminobacte amylophilus were resistant to all the extracts. The potential of inhibition was influenced by the extraction conditions of the phenolic compounds present in propolis. It can be concluded that the LLOS can benefit when given to dairy.