28 November 2022- With the EU ban on pharmacological levels of zinc oxide, and with many other parts of the world pushing to reduce the use of in-feed antibiotics, farmers and nutritionists are left with fewer tools to overcome post-weaning stress. To avoid impacting the success of the animal and of the farm, it is of the utmost importance to ensure the production of top-quality piglets at weaning.
Lallemand Animal Nutrition is investigating ways to boost the resilience of piglets during the transition period using a concept called maternal imprinting: in essence, the idea that what the sow experiences, including what she eats, can have a long-lasting impact on the piglet. Today, we speak with Bruno Bertaud, technical manager for swine applications, David Saornil, product manager for swine applications, and Fernando Bravo de Laguna, R&D project leader for swine, about the emerging body of research demonstrating that the application of Saccharomyces cerevisiae boulardii CNCM I-1079 in sows can have an impact on the progeny’s immunity, microbiology, stress response, and zootechnical performance, positively influencing the farm’s bottom line.
[Feedinfo] What is maternal imprinting? What are some of the various physiological systems of a piglet that can be affected by the experiences of the sow?
[Bruno Bertaud] Maternal imprinting, also defined as maternal programming in the literature, refers to the process by which an acute or chronic stimulus from the mother establishes a permanent response in the progeny that impacts physiological functions later in life. This can happen in utero or in the very first days of life. Depending on the nature and timing of the stimulus, various physiological systems can be differentially affected such as the piglet’s microbiota and immune system for instance, and more generally, characteristics such as growth performance and feed efficiency.
[Feedinfo] Would feeding a probiotic to a sow function as a stimulus for the purposes of maternal imprinting? What kinds of effects have been seen in piglets following probiotic use in sows?
[David Saornil] Yes, and given Lallemand's areas of expertise, we are most interested in exploring the use of nutritional stimulants like this. In a study published by Le Floch et al. 2022 it was shown that sows supplemented with the specific probiotic strain Saccharomyces cerevisiae boulardii CNCM-I-1079 (Levucell SB) have a different microbiota profile than non-supplemented sows. Even several days after weaning, piglets from sows supplemented with this live yeast also have a different microbiota profile than piglets from control sows. By modulating sows' microbiota profile, Saccharomyces cerevisiae boulardii CNCM-I-1079 influences the piglet microbiota profile.
[Feedinfo] How long do the impacts of maternal imprinting last?
[Bruno Bertaud] The early influence of the sow on their piglets, even that which occurs before piglets’ birth, can produce a profound and long-lasting impact on the offspring which goes much beyond weaning.
For instance, the effects of sows’ microbiota can be detected on their offspring’s microbiota 20 days after weaning, despite the significant shifts that weaning itself causes on the microbiome. A study published by Martinez-Miró et al. in 2016 even showed that the salivary cortisol of piglets at 67 days of age was significantly higher for piglets born from stressed sows compared to piglets born from non-stressed sows. The more we learn about maternal imprinting, the clearer it becomes that this is not simply a temporary boost for preweaning piglets, but a mechanism for impacting a sow’s offspring through weaning and beyond.
[Feedinfo] Beyond the influence on the gut microbiome, recent studies have also demonstrated connections between maternal nutrition and the immune system. What role does colostrum play in this transfer of immunity?
[Bruno Bertaud] The sow’s microbiota influences the piglet’s immune system development and, consequently, their growth and survival. Having a higher rate of maternally transmitted bacteria is strongly correlated with the expression of intestinal functional genes, suggesting a significant involvement of maternally derived microbes in the maturation of intestinal functions.
At birth and during early life, the piglets are highly dependent on the maternal passively derived immunity for their survival. The transfer of immunity initially occurs through colostrum. The piglets’ survival but also, their later performance, even after weaning, are highly dependent on their colostrum intake at birth as well as the quality and the available quantity of colostrum which is rich in antibodies. Antibodies are big proteins, and they can only get into the piglet’s bloodstream within the first hours of life before the gut closure. It is a very short window where immunoglobulins from the mother, including immunoglobulin G (IgG), can be passed on through colostrum and can be absorbed. During this short window of time, everything which can help increase the colostrum immunoglobulin concentration is more than welcome in order to reinforce piglet immunity.
In this context, a study published by Bravo de Laguna et al., in 2022, has shown that live yeast Saccharomyces cerevisiae boulardii CNCM-I-1079 included into the sows’ diet, has positive results on the IgG colostrum concentration (measured through the Brix index, with a refractometer), increasing the colostrum immunological quality.
[Feedinfo] Ok, so that explains one possible mechanism. But what are we actually seeing in the piglets in terms of maternal imprinting’s impacts on immunity?
[Fernando Bravo de Laguna] We observed that supplementing Saccharomyces cerevisiae boulardii CNCM I-1079 to the sows from 1 week before farrowing until weaning has an effect on the inflammatory response of the piglets after a respiratory challenge (i.e., vaccination against a respiratory pathogen like Actinobacillus pleuropneumoniae). In another recently published study, we investigated different cytokines’ gene expression profile in the lung of the piglets 70 days post-weaning (3 weeks after vaccination). It was interesting to see that all the cytokines were less expressed in the piglets from supplemented sows, suggesting a reduced inflammatory reaction. This is a maternal imprinting effect, which translates to a lower level of challenge after vaccination of the piglets from supplemented sows compared to the piglets from non-supplemented sows.
It is important to indicate that a reduced inflammatory response leaves more energy available for growth of the piglets, as we also observed in this study.
[Feedinfo] What is the gut-lung axis? How does it explain some of the effects seen in these studies?
[Fernando Bravo de Laguna] The gut lung-axis is a bidirectional communication between the gastrointestinal and respiratory tracts. There are more and more references about the correlation between fecal microbiota (its composition or diversity) and the incidence of common respiratory diseases in swine, like PRRS or PCV2, or even with the vaccination response.
Basically, the intestinal microbiota and their metabolites can migrate through the circulatory and lymphatic systems to distal sites, like the respiratory tract, where they have a role in the immune regulation of the lung. If there is an intestinal dysbiosis, a dysfunction in the immune regulation in the respiratory tract can occur. In the other direction, when there is a dysbiosis in the lung microbiota, there is an increase of the inflammatory cytokines, which migrate to the gastrointestinal tract through the lymphatic and circulatory systems, inducing dysbiosis of the intestinal flora.
Indeed, in our study we observed a positive and significant correlation between the expression of the cytokines in the lung and in the intestine, confirming the cross-talk of both compartments. The hypothesis is that the supplementation of live yeast Saccharomyces cerevisiae boulardii CNCM I-1079 to the sows affected piglets’ microbiota in a way that helped them to keep a basal inflammatory status in the lung after vaccination. In other words, the microbiota of the maternally-imprinted piglets may have been less hostile or irritating to these piglets’ immune systems.
[Feedinfo] Meanwhile, when it comes to the farrowing process, what kind of an impact can feeding Saccharomyces cerevisiae boulardii CNCM-I-1079 have on the outcomes for piglets?
[David Saornil] It has been widely documented that supplying this probiotic live yeast to the sows improves their intestinal transit and therefore their intestinal comfort. In addition, it helps them extract more energy from the feed by favoring fiber fermentation in the hindgut. As a visible consequence for the producer, we can easily observe a reduction of constipation symptoms around farrowing and an easier, even shorter, farrowing process. This is visible externally, but when we look into it from a microbiological perspective, we can also observe a more resilient microbial profile and reduced risk of dysbiosis around farrowing.
The newborn piglets are positively impacted through two main mechanisms:
-As the farrowing process goes smoother, there is less risk of piglets getting suffocated in the farrowing channel and piglets are born with a higher vitality level.
-The first microbial colonization of piglets after birth is extremely important when it comes to neonatal diarrhea, and here the sow and its microbial profile play a critical role. By feeding the probiotic to the sows, we help orientate this first colonization, thus reducing the risk of neonatal diarrhea.
[Feedinfo] There is even proof that feeding Saccharomyces cerevisiae boulardii CNCM-I-1079 to sows can reduce stress in the offspring. Can you explain the evidence for this claim?
[Bruno Bertaud] Stress during gestation can induce significant changes in sows’ microbiota and immune system. These changes can be transmitted to the offspring, impacting fetal development and birth weight, with sometimes long-lasting effect regarding susceptibility to disease and behavior. Cortisol is one of the most widely used biomarkers to detect stress in pigs.
A study published by Salak-Johnson et al. in 2022 showed that maternal feeding of Saccharomyces cerevisiae boulardii CNCM-I-1079 to sows during gestation reduced plasma cortisol in piglets at birth and during the first 24 hours of life, implying in utero effect from the mother to the piglets.
[Feedinfo] Beyond exploring the potential of maternal imprinting, what else is Lallemand working on to help farmers produce piglets with lower or no antimicrobial use?
[David Saornil] We firmly believe that appropriate management of different microbial environments is key for a successful post-weaning stage. Today we have focused our discussion on the influence starting from the sows’ gut. Of course, feeding the probiotic directly to post-weaning piglets has multiple benefits too, from intestinal health to microbiota modulation and reduction of inflammatory responses.
In addition to this, we are also successfully working on positive microbial seeding of farm environments, application of probiotics through the drinking water at specific timepoints, application of specific yeast fractions to modulate negative bacteria populations, or alternative protein and fiber sources with a positive combined effect on hindgut microbiota. All these tools are part of our “outside-in” holistic approach.
Published in association with Lallemand Animal Nutrition