The Paraprobiotic Concept

By Francesca Susca, DVM, PhD, Lallemand Animal Nutrition

Pet humanization – anthropomorphism – is a strong trend within the pet industry. As pets live longer and are considered as family members, more and more pet owners want to provide their pets with human-like products and experiences. This has seen many pet product retailers and manufacturers expanding their shelves and drawing inspiration from human lifestyle to provide pet owners with products that make them feel even more connected to their companion. Increasingly, consumers and brand owners are looking for natural and functional ingredients, with a clear mode of action. From this, come many demands and challenges for manufacturers such as viability through processing, shelf life and labelling claims.

Among the functional foods available to consumers, probiotics are well recognized for their benefits on gut health, immunity, and overall wellbeing whilst boasting a sound scientific foundation. However, today there is growing evidence suggesting that supplementation of certain inactivated probiotics may also confer health benefits: these have been called paraprobiotics (Taverniti & Guglielmetti, 2011).

Parap robiotics , what are they

The term ‘paraprobiotic’ was coined by Taverniti & Guglielmetti in 2011 to define inactivated probiotics as ‘non-viable microbial cells (intact or broken) or crude cell extracts (i.e. with complex chemical composition), which, when administered (orally or topically) in adequate amounts, confer a benefit on the human or animal consumer’.

From probiotics to pa rap robiotics

Microbial cell inactivation may be achieved in many different ways. Live probiotic cells can be disrupted either physically or chemically, using for example heat treatment, UV light deactivation, enzymatic or mechanical disruption, pressure, lyophilisation, or acid deactivation. The optimal deactivation method is strain specific and is often heat treatment as it seems most effective and has the least damaging effect on the structure of the cells components, which in turn is linked to their effects within the host.

Lallemand, a global leader in microbial strain selection, characterisation and production, has an inactivation method, tyndallization, adapted for each of its paraprobiotic strains. Tyndallisation, a specific gentle heat treatment process, preserves the molecular membrane and cell structure of the bacteria whilst inhibiting their capacity to reproduce. Such a strain specific inactivation process ensures the production of microbiologically non-viable, yet functionally active microbial cells, which are shelf stable and still able to positively influence human and animal health. The benefits of pa rap

robiotics

Several reviews of research studies on inactivated probiotics have shown beneficial responses in digestive care, immune modulation as well as a potential role in allergy management, with their non-invasive nature being ideal for immunocompromised or vulnerable animals.

Digestive health potential

The ability of paraprobiotics to adhere to different epithelial cell lines has been proven in vitro and is dependent on the species and the strain (Table 1). Strains capable of adhering to the surface of host epithelial cells offer a competitive advantage by reducing the amount of attachment sites available for potential pathogens. This mechanism is defined as competitive exclusion.

Table 1: Adhesion capacity of different paraprobiotic strains of the Lactobacilli species

Strain

L. acidophilus HA-122

Colon cell line (HT29 & Caco2)

++++

Small intestine cell line (FHs74)

++++

L. casei HA-108 L. plantarum HA-119

+++ Legend: ++++ Strong adhesion (X≥40M); +++ Good adhesion (10M≤X<40M); ++ Average adhesion (0,1M≤X<10M) (M=106CFU).

(in vitro studies, Lallemand internal data)

Competitive exclusion potential of paraprobiotics is linked to the composition of the cell surface proteins and glycoproteins. For example, the S layer-proteins (Slp) present in several genus and species of bacteria is determinant of adhesion capacity. In humans, the competition for adhesion sites at gastrointestinal level has been described between heat-treated Lactobacilli and certain common

gastrointestinal pathogens (i.e.: E. coli, Campylobacter, H. pylori) (Piqué et al., 2019). In a Salmonella infected mouse model, the combination of tyndallised lactic acid bacteria has shown to be able to reduce Salmonella invasion and the induced inflammation (Chen et al., 2013). Furthermore heat-treated L. plantarum has been demonstrated to protect against Salmonella infection in mice and to reduce the translocation of this pathogen into different organs, such as spleen or liver, mainly by inhibiting pathogen adhesion and invasion (Ishikawa et al., 2010).

Some strains of heat-treated L. acidophilus have also shown to be involved in the maintenance of the gut barrier integrity and prevention of chronic diarrhoea (Pique et al. 2019; De Almada et al. 2016).

Immune support and potential role in allergies

After inactivation of bacteria, tyndallised cells can release bacterial components with key immunomodulating effects. Specific bacterial components can be recognised by epithelial cells, which help modulate the immune response.

Exopolysaccharides (EPS), surface carbohydrate polymers, are present at the surface of most bacteria. They act as a protective surface layer but they also interact with the surrounding environment. Several in vivo and in vitro studies report immunomodulating effects of EPS from strains of Bifidobacterium and Lactobacillus suggesting they are involved in the cross-talk between the bacteria and host immune system, potentially playing a role in intestinal homeostasis via interaction with intestinal epithelial cells.

In recent years, the beneficial effects of probiotics on immunemediated diseases, such as allergies and asthma, have been documented and explained by the inhibition of the production of IgE (Di Giacinto et al. 2005). Furthermore, many studies have speculated that inactivated probiotics are able to turn a Th2 response into a Th1 or Th0/ Treg response (Treg cells prevent immune responses). This indicates a potential role for paraprobiotics in allergy management (Figure 1). In particular, Slp A from L. acidophilus has been associated with the ability of binding to dendritic cells to induce an immunoregulatory Treg response and to promote mucosal homeostasis (Pique et al., 2019)

Three good reasons for adding paraprobiotics into pet food

With increasing scientific support, paraprobiotics represent a new generation of ingredients for innovative pet food formulation. They combine benefits in digestive care and immune support, with regulatory and technological advantages:

1.

2.

3. Functional:

Adhesion capacity and potential competition with undesirable bacteria

Immunomodulatory properties

Release of active molecules able to stimulate gut epithelial cells

No risk of translocation and/or interference with gut microbiota (inactivated cells)

Technological:

Heat-stable ingredients, compatible with many technological processes

Easy to standardise, transport and store at room temperature

Stable throughout the shelf-life of the finished product

Can be incorporated in various pet food forms; dry or wet food, food supplements or snacks and treats, even with harsh production processes.

Regulatory:

Classified as feed materials

In conclusion, tyndallised microbes are compliant in all species of animal within Europe, North America and many other countries, meaning they can be easily added into manufacturing processes for pet food chains. Due to their many potential benefits within digestive care, immunity and overall well-being, their use within manufactured feed is promising; especially when intestinal microbiota equilibrium is altered in times of stress.

References available upon request. Francesca Susca, DVM, PhD Pet Development Manager, Lallemand Animal Nutrition fsusca@lallemand.com lallemandanimalnutrition.com

Figure 1: The TH1-TH2 immune balance essential to homeostasis and role of L. acidophilus surface cell proteins.