Today’s trend towards the replacement of in-feed antibiotic growth promoters has driven research activities to develop the potential of alternative feed additives such as organic acids, essential oils and probiotics. A specific strain of Enterococcus faecium can play a vital role here.
By Ulrich Altemueller, Jiri Broz and Roland Brugger, DSM Nutritional Products
Performance and maintaining health are two main tasks in animal production. It is therefore important to maintain a well balanced micro-flora (called eubiosis) in the gastro-intestinal tract of farm animals to optimise nutrient absorption. DSM Nutritional Products has grouped many products to achieve that balance in its so-called Eubiotics portfolio, including organic acids, essential oils and probiotics.
Currently, probiotics as microbial feed additives are a regular component of feed formulations. Their positive effect on the growth performance and health of young animals, with resultant economic and safety benefits in livestock production, is generally considered proven. The name probiotics is derived from the Greek probios, meaning ‘for life’. The microbial strains most often encountered in practice are either lactic acid bacteria (lactobacilli, streptococci/enterococci, bifidobacteria) or spore-forming organisms (bacilli). Any micro-organism that is qualifying to be used as a probiotic in animal feed has to be active in the gut of young animals and should meet most, if not all of the following characteristics:
• The bacteria should colonise the gut rapidly. Optimally it is synthesising specific protective substances, such as L lactic acid, short-chain fatty acids, antibacterial agents and/or enzymes acting as an aid in combating pathogens.
• The production of a biofilm as a barrier to pathogenic micro-organisms which is preventing adhesion by bacteria (e.g. E. coli) and viruses to the epithelial cells of the gut wall is an advantage.
• The micro-organism of choice reduces the amount of ammonia, toxic amines and bacterial toxins in the intestine.
• It potentially stimulates antibody production by the gut wall and promotes establishment or restoration of intestinal flora after drug administration.
Based on the different characteristics briefly outlined above, probiotics are able to establish and maintain a physiological balance among the resident intestinal microflora and keep the growth of pathogenic micro-organisms under control. As a result of this gut flora stabilisation, they above all prevent functional and infectious intestinal disorders, limit the occurrence of diarrhoea and thereby lead to balanced digestive activity in the animal.
Ensuring good health in the early stages of piglet life, lays the foundation for improved growth performance.
One of the most remarkable probiotics available is the lactic acid producing strain Enterococcus faecium NCIMB 10415. This probiotic shows most of the characteristics desired and is marketed under the brand name Cylactin®. Through rapid metabolic activity in the intestine by producing biological active L-lactic acid, E. faecium acts as a stabiliser of gut microflora and limits the growth of pathogens especially in the first days of an animal’s life. Systematic stabilisation of gut flora helps to prevent stress-related disorders. Overall the probiotic increases performance parameters like daily gain and feed conversion rate and improves the health status.
Lactating sows and suckling piglets
A field trial involving 60 breeding sows and their piglets was conducted in a production farm in order to evaluate the effects of dietary administration of E. faecium on various performance parameters (Table 1). Two treatments were involved consisting of a negative control (treatment A) receiving basal, non-supplemented diets and treatment B fed the same diets supplemented with E. faecium. The dosage of the probiotic in the diet for lactating sows was at 70 ppm and in the prestarter diet for the suckling piglets at 100 ppm. Each dietary treatment was assigned to 30 sows and their respective litters.
The trial was initiated in late gestation (day 90) and concluded four weeks after the weaning of piglets.
Health status, live weight and feed intake were monitored in sows before and after farrowing. Numbers of born piglets, overall losses until weaning, live weight of piglets at birth and at weaning were monitored as performance parameters. No direct effects of probiotic administration on performance of breeding sows were noted. Mean live weight of suckling piglets in the probiotic group at days 14 and 21 of age was significantly increased by 7.1 and 5.8%, respectively. Mean live weight of weaned piglets (day 28 of age) was significantly increased from 6.89 to 7.33 kg. This effect on growth rate was connected with a significantly increased intake of the prestarter diet.
Piglets before and after weaning
In another study with 162 piglets, the effect of the application of the probiotic was demonstrated on the performance before and after weaning. The health status was daily observed and the incidence of diarrhoea was used as a measurement to quantify the general health status. The extent to which these results are attributable to study-related changes in the microbial colonisation of the GIT in the treated animals can be seen in Figure 1.
The use of the probiotic was associated with a roughly tenfold increase in the number of Enterococci in the investigated gastrointestinal segments. Judicious administration of lactic acid bacteria favoured the establishment of ‘lacto-dominant’ microflora, so that the study piglets were optimally prepared for weaning.
This is reflected in the significantly higher number of lactobacilli in the small intestine of the group fed probiotics at weaning age, as well as a tenfold reduction in the E. coli count. Relative to the control animals, it was thus possible to suppress the energy-consuming microbial processes necessary to maintain eubiosis during the weaning period. The anticipated consequences of this are increased nutrient availability, reduced metabolite production, and hence reduced demands on the host metabolism. The suckling piglets and weaned piglets of the probiotics group displayed significantly better faecal consistency than the untreated animals (see Figure 2). The live weight gains documented during the study are presented in Figure 3. The group fed probiotics exhibited a higher level in both the suckling (+ 3.2%) and the weaning (+ 5.6%) periods.
The stabilisation of health status observed with pig feeds supplemented with E. faecium, especially in the initial periods of life, lays the foundation for improved growth performance. Feeding the mother sow with E. faecium and continuing the treatment during the suckling and weaning period of piglets protects the young animal by immediately establishing a positive gut flora and preventing the invasion of pathogens causing gastrointestinal disorders.
The effect of E. faecium is manifested principally in the small intestine due to the in situ production of biological active L-lactic acid and commences during the processes of microflora stabilisation in the first hours or days of life. In general, systematic stabilisation of gut flora helps to prevent stress-related digestive disturbances at weaning, feed changes, rehousing or transportation. In addition, the available evidence indicates that probiotics provide an effective alternative to the use of growth promoters in pig farming as a stand alone solution or in combination with organic acids or essential oils.