PREBIOTICS AND

PROBIOTICSRavi kanth Reddy. Punuru

gvm/12-001BY

Parker coined the term ‘probiotic’ in 1974 and defined it as “organisms and substances which contribute to intestinal microbial balance”.Probiotics are live cultures of non-pathogenic organisms which are administered orally.Later Fuller in 1989 redefined them as live microbial feed supplements which beneficially affect the host animal by improving its intestinal microbial balance.They may include microbial cells, microbial cultures and microbial metabolites.Most probiotics get destroyed by upto 80% in the presence of antibiotics or when mixed with antimycoplasma drugs in the feed.

INTRODUCTION :

The US food and drug administration (USFDA) used the term direct fed microbes(DFM) instead of probiotics.

Available forms :Probiotic products are available in the form of oral pastes, water dispensible powders or liquids or directly fed feed additives.Some companies developed thermo-positive process to formulate microbial cultures and microbial viabilityis assured in the pelleted feeds. Eg: primalac DFMSome developed viable bacterial spores of selected bacillus strain which are heat resistant.The recovery rate of organisms after pelleting is 95 %.

The DFM, includes : various bacterial cultures and yeast cultures.Various bacterial cultures includes :

Lactobacillus spp :L.acidophilus, L.casei, L.delbreukii subsp.bulgaricus, L.brevis, L.cellobiosus, L.curvatus, L.fermentum, L.lactis, L.plantarum, L.reuterii

Streptococcus spp :S.cremoris, S.faecium, S.diacetylactis, S.intermedius thermophilus, S.lactis

Bifidobacterium spp :B.bifidum, B.adolescentis, B.animalis, B.infantis, B.longum, B.thermophilum

Aspergillus spp : A.oryzae

Various yeast or fungal cultures includes :

Saccharomyces spp : S.cerevisiae, S.boulardii

Formerly yeast is known to contain compounds formerly referred to as UGFs (unidentified growth factors).Hungate (1966) observed that rumen bacterial concentrations increased when fermentation products such as yeast cultures were added to the diet.He concluded that the stimulatory effects was due to metabolites in the fermentation products which served as nutrients for the bacteria.

Byproducts of fermentation includes : Dried brewers yeast , dried distillers solubles, dried bacterial press cakes.An increase of 1.1 kg milk yield/day with inclusion of 50 gms of an active yeast/day was noticed.

: Effect of yeast :

On animal physiology :Reduces the temperature in heat stressed animals.Not shows effect regarding physiology in cool weather.The mechanism of action exerted by fungal cultures on body templ and resp. rate is unclear.

Yeast culture

Increased bacterial population

Increased flow of microbial protein

Increased degradation of fibre in rumen leading to increased feed intake

Increased animal productivity

Action of yeast culture in Ruminants

Characteristics of a good probiotic :

The culture should exert a positive effect on the host. It should be gram positive, acid resistant, bile resistant and contain a minimum 30×109 CFU per gram.The culture should possess high survival rate and multiply faster in the digestive tract. It should be strain specific.The culture microorganisms should neither be pathogenic nor toxic to the host.The adhesive capability of microorganisms must be firm and faster.Should be durable enough to withstand the duress of commercial manufacturing, processing and distribution so that the product can be delivered alive to the intestine.

: Mode of action of probiotics :Competitive exclusion :Oral administration of a suspension of caecal contents or faeces obtained from adult chickens to newly-hatched chicks increase their resistance to oral infection by salmonella and this phenomena is called competitive exclusion(Nurmi and Rantala,1973).A direct competition between native gut flora and Salmonella for attachment to a local site in gut epithelium is noted.In the healthy animal Lactobacilli colonize quickly in the gut to displace the coliforms and reaching population of 107 to 109 by one week of age (Karney et al).

Acid production and lowering of PH :

The lactic acid bacteria produce organic acids like acetic and lactic acids in large quantities, which reduce intestinal PH(Fox 1988).The organic acids are toxic for the undesirable microflora in the intestine and this toxicity is increased manifold at low PH , as the undissociated form of these organic acids has better penetration into the bacterial cells and disrupting the bacterial cell.The antagonistic effect of Lactobacillus against Enterobacterium and Salmonella is due to lactic acid production.

The antagonistic activity of lactic acid bacteria towards pathogens can be attributed to the production of bactericidal substances like :- Acidophilin, Acidolin, lactobacillin, lactocidin e.t.c…..These antibacterial compounds have been found effective against Salmonellae,Shigellae, proteus, Klebsiella, E.coli, Pseudomonas, e.t.c….Hydrogen peroxide produced by some Lactobacillus spp. Appears to be partially responsible for the antagonistic interaction since it has strong germicidal activity at low PH environment (Gilliland, 1990).

Excretion of antibiotic like substances :

Deconjugation of bile salts :Most of the lactic acid producing bacteria has the ability to deconjugate bile acids to free from i.e. cholic acid, deoxycholic acid and taurocholic acid.This deconjugation of bile acids by the probiotic culture enhances its anti-microbial nature and the production of anti-microbial compounds (Acidolin and Reuterin), which further reduce the population of harmful bacteria in the gut(Juven et al,. 1991).

acids

acids

acidsproduction of anti-microbial compounds

Microbial enzymes are beneficial to the host because they increase the digestion of nutrients especially in the lower intestine (Sissons, 1989).Lactobacillus spp., which was used in cheese products, was found to have lipolytic, amylolytic and proteolytic activities (Lee and Lee, 1990).

Digestive enzyme activity :

Antimutagenic and anticarcinogenic activity :Microbial feed additives suppress the activity of mutagenic compunds.The activities of carcinogenic enzymes such as nitroreductase, azoreductase and β-glucuronidase in the guts of rats can be reduced by supplementation of Lactobacillus acidophilus (Goldin and Gorbach, 1977).

Ammonia production :Yeo and kim (1977) reported that feeding of probiotic (L.casei) significnatly decreased the urease activity in the small intestinal contents of broiler chicks during the first 3 weeks.This suppression of ammonia production and urease activity by probiotic culture may be beneficial for improving animal health and enhancing growth because ammonia produced by ureolysis in the intestinal mucosa can significantly damage the surface cells.Also beneficial for minimizing respiratory problems and reduces environmental pollution from poultry farming.

Anticholesterolemic effects :Feeding of Lactobacillus decrease the level of cholesterol in serum.The anti-cholsteromic activity of lactic acid bacteria is expressed by 3 ways :

By inhibiting cholesterol synthesisBy inhibiting intestinal absorption andBy deconjugation fo bile salts (DeRodas et al,. 1996).

Immunomodulation :DFM activate immune system by increasing the phagocytic activity of lymphocytes, production of T-helper cell mediated cytokines by spleen cells and inhibition of IgE and IgA production and by protecting the Gut associated lymphoid tissue (GALT) to come in contact with different antigens (Saloff coste 1995).

Enhancing feed intake and digestion :

The microbes take part in the metabolism of dietary nutrients such as carbohydrates, protein, lipids and minerals and also in the synthesis of vitamins.Nahason et al,.(1992) reported that supplementation of lactobacillus culures in maize-soyabean diets increased the retention of nitrogen, phosphorous, copper and manganese in layers.

Advantages of supplementation of DFM in various sps :

DFM for calves :During the first 2 weeks of the calf’s life, it is especially easy for toxin-producing coliform bacteria like E.coli to colonise the gut.This irritates the intestinal tract, resulting in a ‘hyper-secretion’ of fluids that leads to scours.Certain types of DFM oral pastes and feed supplements are designed to prevent or reduce E.coli scours in calves.Stress such as extreme weather or transportation, would more likely enhance the potential benefit of feeding a DFM to calves.

DFM for pigs :Probiotics have shown the greatest potential in very young and growing pigs.Feeding probiotics improved weight gain and feed efficiency.Sows consuming diets supplemented with probiotic bacteria weaned larger, heavier litters.

Litter size at weaning 9.7 9.0*Pre-weaning mortality (%) 7.0 12.1*Piglet diarrhoea score 0.08 0.24*Piglet weight at weaning (kg) 8.40 8.02*Total creep feed intake per litter 6.4 5.9*

Probiotic group Control group

Probiotic effect on pre-weaning piglet performance

DFM for poultry :The role of the intestinal microflora in health and digestion of poultry is more extensively understood than in mammalian species.A low PH favours Lactobacillus sp. And a high PH is optimal for E.coli.It was reported that Lactobacilli can be found in crop epithelial tissue as early as day one of life. These microbes attach to the crop epithelium and colonize the surface.Supplementation of a lactobacillus product in the water or feed along with an acidifying agent would be effective in controlling the coliform proliferation.Lactobacillus stimulates the weight gain and feed efficiency of broilers.

DFM for ruminants:Feeding probiotics leads to increased fibre digestibility and hence production of animals.Significant improvement in feed intake, feed conversion efficiency and growth performance is noticed in cattle, sheep and goat.Also inhibited methane production. The probable ways of inhibition of methane production are :

1) By increasing butyrate or propionate2) By reducing protozoa numbers thus affecting adversely the methanogens associated with the protozoa.3)By stimulating the growth of acetogens which utilize hydrogen thus channalizing hydrogen towards acetate production.

Considerations in use of proibiotics :The response to probiotic feeding depends on a number of factors such as composition of the product, viability and stability of the culture, dosage rates, duration of feeding, method of administration, ages of the animal used in the research studies, effects of environmental and nutritional factors on probiotic viability in the intestines and form of the culture.The positive influence shown with a particular probiotic may not always be repeatable in other similar experiments and the influence will be more pronounced in stressful conditions.It is highly advisable to adhere to storage recommendations (i.e., away from moisture, excess heat and light) for maintenance of stability of the probiotic.

Examples of commercial preparations :YEA-SACC 1026 , VETCARE - DOSE 1 KG/tonn of broiler feed. 400-600 gm/tonn of layer feed.

Lacto-sacc (Microencapsulated Lactobacillus, Streptococcus, enzymes and yea-sacc1026 ), vetcare/Alltech,Inc.

Nutri-sac for dairy cows (contains bypass protein, niacin, selenium and yea-sacc1026 ) Dose : calves 100 gms/head/day, cows 200 gm/head/day.

: PREBIOTICS :Introduction :

A prebiotic is a non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth or activity of one or a limited number of bacteria in the colon and thus improves the host health (Gibson and Roberfroid, 1995).Efficient prebiotic need to induce a specific fermentation in the colon.

Characteristics of a good prebiotic :Should be neither hydrolyzed nor absorbed in the upper part of the GIT.Should be a selective substrate for one or limited number of bacteria commensal to caecum/colon, which

Are stimulated to grow or metabolically activated.Able to alter the colonic flora in favour of a healthier composition.Induce systemic effects that are beneficial to the host’s health.Should have known structure, which can be documented. should be palatable as food ingredient and large-scale processing must be easy.

Types of prebiotics :Glucooligosaccharides(GOS), fructooligosaccharides(FOS), mannanooligosaccharides(MOS), trans-galactooligosaccharides(TOS), isomaltooligosaccharides, lactosucrose, polydextrose, soybean oligosaccharides(SOS),

and xylooligosaccharides Others are :- germinated barley foodstuffs, oligodextrans, gluconic acid, gentiooligosaccharides, pectic oligosaccharides, mannan oligosaccharides, lactose, glutamine, hemicellulose-rich substrate, resistant starch and its derivatives, oligosaccharides from melibiose, lactoferrin-derived peptide, and N-acetylchitooligosaccharides.

Lactose :Is a disaccharide consists of glucose and galactose.Due to the absence of lactase enzyme in chicken intestine, the ingested lactose asses intact through and enters to the lower segment of the intestine and caeca.The hydrolyzation of lactose that occurs is primarily due to microbial utilization of the disaccharide.

Fructooligosaccharides (FOS) :They can be found naturally in some cereal crops and onions.FOS consists of several β(1-2) or β(1-6) linked fructose units which may be linked to glucose residues.They stimulate the growth of bifido bacteria and to inhibit growth and multiplication of potentially pathogenic bacteria such as enterobacteria, clostridia and salmonella.

Fermentation of FOS leads to the production of short chain fattyacid, which is substrate for energy metabolism in the colonic mucosa stimulating epithelial cell growth.

Relationship b/w bifidobacteria and short chain fructooligosaccharides

mannanoligosaccharides (MOS) :

MOS is obtained from the cell wall of yeast (saccharomyces cerevisiae).Mannose, the main component of MOS, is a unique sugar because many enteric bacteria have receptors that bind to it and carried out of the gut.The pathogenic bacterial cells have surface compounds called lectins which recognize these carbohydrates and by which they attach to the gut cells.The pathogenic bacteria binding to the enterocytes is disrupted and instead they bind to the oligosaccharide and are carried out of the gut with the passage of the digesta.

Lectin-carbohydrate combination

Partially hydrolysed guar gum (PHGG) :It is the one of the most commonly used polysaccharide prebiotic for chickens.Obtained from the bean of cyamposis tetragonoloba.By selectively cleaving the mannan backbone chain of guar gum using endo- β – D-mannnase, a mixture of galactomannans is obtained, which is known as PHGG.

Inulin :Inulin, a linear β - fructan, is present in a variety of plants including chicory root and wheat. It exhibits prebiotic properties and has been shown toenhance mineral absorption and increase beneficial bacteria in the colon.The Lactobacillus and Bifidobacterium populations were significantly increased in the inulin supplementation.

Diet fed with inulin and without inulin

: Mechanism of action of prebiotic :

Dietary oligosaccharides may directly inhibit the growth of certain intestinal pathogens by increasing the concentration of lactic acid and there by decreasing ph in the lower gut (Choi et al,. 1994, okumara et al,.1994).

By lowering the gut ph through lactic acid production:

By inhibiting/preventing colonization of pathogens :Microbes are able to attach to the mucosa through fimbriae and competitively decreases the pathogenic bacteria.

Modifying metabolic activity of normal intestinal flora :saccharides indigestible by the host are fermented by the flora into volatile fattyacids (actate, propionate and butyrate), lactate and several gases including CO2, methane and hydrogen (Cummings, 1981).short chain fattyacids released from the fermentation are metabolically utilized by the epithelial tissue of the intestine and also play a role in modulating endogenous metabolism (Demigne et al., 1986).

Stimulation of immune system :May stimulate the blood immune system after crossing the intestinal mucosal barrier.Some pathogenic bacteria causes disease after translocation through the intestinal wall and it is most common in animals fed with fibre free diet.The oligosaccharides acts as soluble fibre and reduce translocation and help to preserve systemic immunity (Monsan and Paul, 1995).

: PRACTICAL APPLICATION :Growth and nutrient utilization :The diets containing 0.4% FOS resulted in significant improvement in average daily gain and feed efficiency (Xu et al.(2003).MOS derived from palm kernels increased the muscle weight gain in chickens when included at 0.3% diet (Puszati et al., 1995).MOS also reduced the mortality of chicken and improved the performance . (Mc donald 2005).The ileal digestibilities of DM, Ca, P and CP was increased significantly.Compunds such as FOS can be fermented by the favourable bacteria, giving them a competitive advantage.

final Body wt. in chicks with and without prebiotics supplementation

Dietary supplementation of MOS reduces the excretion of nitrogen and phosphorous and thereby minimizes the major sources of environmental pollution.

Poultry health :The use of prebiotics in the diets has been assumed to minimize the use of antibiotics and thus possible occurrence of drug resistance in bacteria.FOS is effective against Salmonella (Fukata et al,. 1999) and Campylobacter (Schoeni and Wong, 1994).Dietary MOS had reduced caecal S.typhimurium concentrations (Spring et al,. 2000).Supplementation of PHGG in young hens, resulted in no salmonella enteriditis.

: CONSIDERATION :Depends up on The criteria for including these studies in the analysis were that the available report should have included at least 1) the daily dose of the prebiotic, 2) the nature of the prebiotic, i.e., inulin or oligofructose, 3) the number of volunteers, and 4) the number of bifidobacteria per gram of feces both at the beginning and at the end of the supplementation period.

THAN “Q”

Ravi kanth Reddy. Punurugvm/12-001

BY