Efeito da concentração de bactérias probióticas como imunomodulador da produção de anticorpos antirrábicos em bovinos vacinados

<p>Esse estudo avaliou o efeito da suplementação de uma associação de microrganismos probióticos, adicionados à mistura mineral em diferentes doses, na produção de anticorpos séricos antirrábicos em bovinos primovacinados. Os Quarenta e dois bovinos Nelore machos, com idade de 12 meses, foram divididos em três grupos (n=14): grupo controle (GC) recebeu 70 gramas de mistura mineral/animal/dia; grupos probiótico 2 gramas (G2P) e 8 gramas (G8P) receberam 70 gramas de mistura mineral/animal/dia adicionados respectivamente de 2 e 8 gramas de probióticos (Lactobacillus acidophilus, Streptococcus faecium, Bifidobacterium thermophilum e Bifidobacterium longum). títulos individuais de anticorpos antirrábicos foram determinados por meio da técnica de soroneutralização em células baseado no rapid fluorescent focus inhibition test (RFFIT). Os resultados obtidos foram comparados pelo teste t não pareado, com 5% de nível de significância. Houve diferenças estatísticas significativas entre as médias de concentrações séricas entre os grupos GC e G8P, após 30 e 60 dias da primovacinação e após 60 dias, somente o G8P manteve 100% com títulos de anticorpos protetores mínimos. Houve também melhora na produção de anticorpos no grupo G2P em relação ao GC, após 30 e 60 dias, porém não significativa. Conclui-se que as doses crescentes de probiótico adicionadas na mineral interferiram beneficamente na resposta imune humoral antirrábica, determinada pela concentração sérica de anticorpos, assim como permitiu a manutenção por um período maior os títulos protetores mínimos nos bovinos primovacinados<strong>. </strong></p>

Effect of Bifidobacterium thermophilum RBL67 and fructo-oligosaccharides on the gut microbiota in Göttingen minipigs

Modulating the gut microbiota via dietary interventions is a common strategy to enhance the natural defence mechanisms of the host. Several in vitro studies have highlighted the probiotic potential of Bifidobacterium thermophilum RBL67 (RBL67) selected for its anti-Salmonella effects. The present study aimed to investigate the impact of RBL67 alone and combined with fructo-oligosaccharides (FOS) on the gut microbiota of Göttingen minipigs. Minipigs were fed a basal diet supplemented with 8 g/d probiotic powder (1×109 CFU/g in skim milk matrix) (probiotic diet (PRO)), 8 g/d probiotic powder plus 8 g/d FOS (synbiotic diet (SYN)) or 8 g/d skim milk powder (control), following a cross-sectional study design. Faecal and caecal microbiota compositions were analysed with pyrosequencing of 16S rRNA genes and quantitative PCR. Metabolic activity in the caecum and colon was measured by HPLC. 16S rRNA gene amplicon sequencing revealed that minipig faeces show close similarity to pig microbiota. During the treatments and at the time of killing of animals, RBL67 was consistently detected in faeces, caecum and colon at numbers of 105–106 16S rRNA copies/g content after feeding PRO and SYN diets. At the time of killing of animals, significantly higher Bifidobacterium numbers in the caecum and colon of SYN-fed minipigs were measured compared with PRO. Our data indicate that the Göttingen minipig may be a suitable model for gut microbiota research in pigs. Data from this first in vivo study of RBL67 colonisation suggest that the combination with FOS may represent a valuable symbiotic strategy to increase probiotic bacteria levels and survival in gastrointestinal tracts for feed and food applications.

Growth-promoting effects of caseinomacropeptide from cow and goat milk on probiotics

Caseinomacropeptide (CMP), a 7-kDa phosphoglycopolypeptide fragment released from κ-casein during milk renneting, is heterogeneous with respect to post-translational glycosylation. Several studies have reported that CMP has growth-promoting activity on lactic acid bacteria belonging to the genera Bifidobacterium. The aim of this study was to evaluate the effect of glycosylation and sequence variations between bovine and caprine CMP on the growth of two probiotics: Lactobacillus rhamnosus RW-9595-M and Bifidobacterium thermophilum RBL67. The growth-promoting activities of CMP (mixture of glycosylated (gCMP) and non-glycosylated (aCMP) fractions), aCMP and gCMP were measured in a basal minimal culture medium using turbidimetric microplate assay at 37 °C. Supplementation of the culture media at 2 mg/ml significantly improved maximum growth by 1·5 to 1·8 times depending on the strain, the additive (CMP, aCMP, gCMP), and the bovine or caprine origin (P < 0·05). CMP preparations also decreased the time needed to reach the inflexion point of the growth curve and increase the cell density at that time (P < 0·05). The effects of CMP preparations were dose dependent and significantly superior to the effect of bovine β-lactoglobulin added to the culture media. As gCMP and aCMP were as efficient as bovine and caprine CMP (P > 0·1), it was concluded that the presence of oligosaccharides linked to CMP was not essential for growth-promoting activity of CMP.