Manipulation of the Gastrointestinal Microbiota by Application of Probiotic Microorganisms

Administration of preparations based on autochthonous microorganisms is a very effective method of affecting the microbiota of the gastrointestinal tract in farm animals. In this way development of the microbiota of the young at an early age and around weaning can be influenced.

Development of the rumen microbiota in calves and lambs can be supported by microbial preparations mainly at the start of dry feeding. Effective use of microbial preparations in the young depends also on the level of knowledge of the so-called environmental factors in the rumen which determine the age at which a given microorganism may colonize the rumen and enable the development of cellulolytic microbiota (71). The specificity of using probiotics in calves, lambs and goatlings consists in the possibility of influencing the formation of the ruminal ecosystem; application of selected strains of rumen microorganisms lays the foundation of a future population showing a high fermentation activity. Colonization with selected cultures of living microorganisms should enable an earlier and more stable onset of the ruminal type of digestion. Controlled action on the rumen microbiota in the young during milk nutrition is mainly related to the effect upon development of the microbiota adhering to the epithelium of the rumen wall. The effects of stimulation can be expected to be most pronounced at the period of the most rapid development of the adherent microbiota, at 2 to 3 weeks of age. Autochthonous species colonizing the rumen immediately after birth are of decisive importance. This microbiota, though simple at the beginning, enables the development of a cellulolytic population and that of ruminal digestion. Strains of Streptococcus bovis may be used to stabilize rumen fermentation. During a 4-week administration of a colonizing preparation containing S. bovis AO 24/85 to lambs the numbers of S. bovis germs adhering to the rumen epithelium were significantly increased (p< 0.001) and so was their alpha-amylase activity (72). In order to promote the development of the ruminal microbiota Kopecny and Simunek (73) used a mixture of rumen bacteria that contained amylolytic, cellulolytic, hemicellulolytic, saccharolytic, proteolytic and lactate-utilizing strains.

It is of great importance to influence the intestinal microbiota of calves, piglets and poultry at an early age since this is the period when the danger of diarrhea-accompanied diseases of the digestive tract reaches its maximum. Due to their high morbidity and mortality rates such diseases present an extraordinarily serious health and economic issue. Preventive application of probiotics at an early age helps to optimize the composition of the gut microbiota and has an inhibitory effect upon the pathogens of the digestive tract in the young of farm animals. Preventive application of Lactobacillus casei at a dose of 1.108 germs decreased the counts of enterotoxigenic E. coli O101:K99 adhering to the small intestinal mucosa of gnotobiotic lambs by 99.1% and 76.0% on day 2 and 4 after inoculation, respectively (74). Perdigon and coworkers (75) found the preventive effect of L. casei and yoghurt against Salmonella typhimurium infections in mice to depend on the duration of administration. The short-term preventive application of Lactobacillus paracasei (76) induced slight decrease in number of E. coli adhered to jejunal mucosa of gnotobiotic piglets, while continuous application led to significant (p< 0.05) decrease (Fig. 1). Thomke and Elwinger (77) and Mead (78) suggested that it seems possible to lower enteropathogens (E. coli and Salmonella) but not to control them by administering Lactobacillus acidophilus. Increased lactic acid production in the small intestine of pigs fed lactobacilli and yeast caused a decrease in intestinal pH and the presence of E. coli within in intestinal content (79).

Potentiation of the probiotic effect of microorganisms seems to be possible by combining them with synergically acting components of natural origin. As such, prebiotics (mainly oligosaccharides), substrates and metabolites of microorganisms and phyto-components are taken into consideration. Bomba and coworkers (80) showed that the administration of L. paracasei alone had almost no inhibitory effect on the adhesion of E. coli to the jejunal mucosa of gnotobiotic and conventional piglets while L. paracasei administered together with maltodextrin decreased the number of E. coli colonizing the log 10.cm-2

short-term continual

Figure 1 Colonization of the jejunal mucosa of gnotobiotic piglets by Escherichia coli 08: K88 at short-term and continual preventive application of Lactobacillus paracasei. (□) Control group E; (■) experimental group L-E. Source: From Ref. 76.

short-term continual

Figure 1 Colonization of the jejunal mucosa of gnotobiotic piglets by Escherichia coli 08: K88 at short-term and continual preventive application of Lactobacillus paracasei. (□) Control group E; (■) experimental group L-E. Source: From Ref. 76.

jejunal mucosa of conventional piglets by 2.7 logarithm (4.75 log 10/cm2) in comparison to the control group (7.42 log 10/cm2, p<0.05).

Findings reported by Nemcova and coworkers (81) pointed at the fact that the probiotic effect of microorganisms could be potentiated by combining them with prebiotics. The application of L. paracasei combined with fructooligosaccharides to piglets for the first 10 days of life and 10 days after weaning revealed an effect upon bacterial counts in the faeces that was significantly more positive than that of lactobacilli only. With this combination significantly increased counts of Lactobacillus species, Bifidobacterium species, total anaerobes and aerobes as well as significantly decreased counts of enterococci were stated in the faeces when compared to the control as well as the Lactobacillus only group. Comparison with the controls revealed the combination of lactobacilli and fructooligosaccharides to result in a significant decrease of Clostridium and Enterobacteriaceae and an insignificant decrease of coliform counts in the faeces of piglets. These results prove a synergically positive effect of L. paracasei and fructooligosaccharides in the faecal microbiota of piglets (Table 1).

Our results showed that the application of L. paracasei combined with fructooligosaccharides and maltodextrin decreased the preweaning mortality of piglets (Fig. 2). The field trial lasted eight months and comprised 4000 heads of 1-35 days old piglets and the results were compared with the same period of the previous year in which antibiotic feed additivies were used.

Competition for receptors on the intestinal wall is one of the mechanisms that mediates the inhibitory effect of probiotic microorganisms on the adhesion of pathogens to the intestinal mucosa. Based on this fact it can be hypothesized that an increase in the number of probiotic microorganisms colonizing the intestinal epithelium may potentiate their probiotic effect. From this point of view the findings of Ring0 and coworkers (82) about the effects of lipids containing feeds on the gastrointestinal microbiota and especially on the population of lactobacilli are of great interest. According to Kankaanpaa and coworkers (83) higher concentrations of polyunsaturated fatty acids inhibited the growth and mucus adhesion of selected lactobacilli whilst growth and mucus adhesion of Lactobacillus casei Shirota was promoted by low concentrations of g-linolenic acid and arachidonic acid. In gnotobiotic piglets oral administration of oil that contained polyunsaturated fatty acids significantly increased the numbers of Lactobacillus paracasei

Table 1 Composition of Fecal Microbiota in Weanling Pigs Receiving Lactobacillus paracasei and Mixture of Lactobacillus paracasei and Fructooligosaccharides

Organisms

Group 1

Group 2

Group 3

Total anaerobes

9.8 + 0.2

9.8 + 0.3

10.2 + 0.2 a*, b*

Total aerobes

8.0 + 0.5

8.2+ 0.2

9.3 + 0.7 a*, b*

Bifidobacterium

7.5 + 0.3

7.1+0.7

8.3 + 0.3 a*, b*

Lactobacillus

9.9 + 0.1

9.9 + 0.3

10.3 + 0.1 a**, b*

Enterococcus

9.3 + 0.1

9.3 + 0.3

8.2 + 0.2 a***, b***

Clostridium

8.1 + 0.1

7.4 + 0.4 a*

7.7+0.3 a*

Enterobacteriaceae

7.9 + 0.4

6.5 + 0.9 a*

5.9+0.9 a**

Coliforms

6.8 + 0.7

6.3 + 0.7

5.8+0.7

Values are mean + SEM of log bacteria counts per gram of wet feces (n = 7). Group 1—control. Group 2—Lactobacillus paracasei. Group 3—Lactobacillus paracasei and FOS.

(a) Significantly different from control group.

(b) Significantly different from Lactobacillus paracasei group. *p<0.05; **p<0.01; ***p<0.001.

Source: From Ref. 81.

Values are mean + SEM of log bacteria counts per gram of wet feces (n = 7). Group 1—control. Group 2—Lactobacillus paracasei. Group 3—Lactobacillus paracasei and FOS.

(a) Significantly different from control group.

(b) Significantly different from Lactobacillus paracasei group. *p<0.05; **p<0.01; ***p<0.001.

Source: From Ref. 81.

adhering to the jejunal mucosa as compared to the control group (84). It is suggested that polyunsaturated fatty acids could modify the adhesion sites for gastrointestinal microorganisms by changing the fatty acid composition of the membranes of the intestinal epithelial cells (82). The ability of probiotics to adhere to mucosal surfaces is a presupposition of their health-promoting effects. The stimulatory effect of polyunsaturated fatty acids upon the adhesion of lactobacilli could be used to enhance the effectiveness of probiotics in inhibiting the pathogens of the digestive tract.

Early colonization of the gut by an autochthonous microbiota protects chickens from Salmonella infection. The direct competition for the site of attachment is suggested to be the prime mechanism for the competitive exclusion (85) and development of a biofilm of protective microbiota was observed using scanning electron microscopy. The method of competitive exclusion constitutes an additional prophylactic method that may be applied directly in the animal to enhance its resistance towards Salmonella infection (86). It is also considered a possible application in preventing colonization of poultry with E. coli O157

Figure 2 Total preweaning mortality of the piglets during control period July 2000-February 2001 and during experimental period July 2001-February 2002. (□) 2000, 2001 (■) 2001, 2002.

and Campylobacter jejuni (78). Optimal protection against S. typhimurium was observed when broiler chicks were treated with a culture of caecal microbiota in combination with dietary lactose (87). The same results were described in turkey poultry (88) and layer chicks (89). In poultry, lactose can also be considered a prebiotic because of absence of the endogenous lactase. The lactose is converted into lactic acid by fermentation of hindgut microbiota. The decrease of intestinal pH results in reduction of the S. typhimurium concentration.

Was this article helpful?

0 0
Pregnancy And Childbirth

Pregnancy And Childbirth

If Pregnancy Is Something That Frightens You, It's Time To Convert Your Fear Into Joy. Ready To Give Birth To A Child? Is The New Status Hitting Your State Of Mind? Are You Still Scared To Undergo All The Pain That Your Best Friend Underwent Just A Few Days Back? Not Convinced With The Answers Given By The Experts?

Get My Free Ebook


Post a comment