November 15, 2017

Lallemand hosts 9th International Levucell SB Technical Meeting

Vietnam is the second largest pig producer in Asia after China, with 2.45 million tonnes of pork produced and about 4.2 million sows in 2015. At a time when the country is strengthening efforts to reduce antimicrobial usage in livestock production, 110 swine and nutrition experts from Asia, Europe, Australia and South America gathered in Ho Chi Minh City for Lallemand Animal Nutrition's 9th International LEVUCELL SB technical meeting.

Once again, this was a great opportunity to share experiences and scientific knowledge. The first session was dedicated to sows and fattening pigs, and particularly the growing issues linked to heat stress and hyperprolificity. The session featured renowned international speakers. This was followed by a second session dedicated to post-weaning piglets, providing the latest scientific updates on the impact of weaning on piglets' microbiota and how this affects future health and performance.

The growing impact of heat stress worldwide

David Renaudeau, from INRA in France, explained heat stress is not limited to tropical countries, since it is a growing issue in the South of Europe or the Midwest U.S.A., for example. This is a trend bound to increase with global warming. He stressed the fact that modern genetic selection has increased animals' susceptibility to heat stress, selecting productive traits at the expense of robustness.

Renaudeau reviewed the impact of heat stress on sow production, in particular in relationship to feed efficiency. Heat stress in lactating sows:

- Decreases feed intake, increasing body weight loss in lactation
- Reduces milk production and, consequently, litter growth
- Impairs reproductive performances for the next cycle (weaning to oestrus interval increased, farrowing rate decreases)

In the growing-finishing phase, Renaudeau showed how heat stress affects feed efficiency and that pig sensitivity to heat stress increases with body weight.

In Brazil, heat stress is a well-known issue. Professor Bruno Silva, from the Institute of Agricultural Sciences, Universidade Federal de Minas Gerais in Brazil, is a specialist in the field of nutritional requirements and environmental adaptation of pigs in tropical regions. He explained how climatic effect is intensified with modern sows' genotypes, due to high growth rates, deposition of muscle tissue and hyperprolificity. He also stressed the effect of heat stress on oxidative stress in sows.

Christopher Brewster - a swine nutritionist with Australia's leading pig producing company Rivalea that processes one million pig/year - draw economic connections between the Australian pig market and heat stress. He estimates that feed intake is typically decreased by 10-20%, leading to lower carcass weight and profit, especially at times of higher market demand in Australia, which coincides with the Christmas market.

Approaches to alleviate heat stress

Four types of approaches to reduce the impact of heat stress were discussed by the speakers:

- Environmental heat abatement methods - spray or drip cooling, floor cooling etc. - are very effective but not always economically feasible, especially in small-scale tropical operations. Silva presented different cooling systems, explaining how "contact" cooling systems such as cooling floors are more effective than convective systems.

- Nutritional strategies, including dietary adaption such as feeding high energy diets to compensate for the reduced feed intake (Renaudeau recommends a diet with >10 MJ NE/kg), but also high fat/low crude protein diets. In addition, the use of feed additives to enhance feed efficiency, such as live yeast, or flavorings to stimulate feed intake, were discussed. Antioxidant supplementation should also be considered to protect the animals.

- Feeding management practices are also key. For example, Silva, recommends feeding animals when temperature are the lowest, since feed intake is shown to peak twice a day - in early morning and late afternoon. He also stressed the importance of the quality and temperature of drinking water, which are often overlooked at farm level. Silva explained how, when entering a pig farm, water quality is the first thing he looks at and brings it to the farmer’s attention to by serving them a glass of water and asking "would you drink it?"

- Finally, as longer term strategy, genetic adaptation is also in the pipeline.

What about live yeast?

Along the session, various trials with the scientifically documented live probiotic yeast strain Saccharomyces cerevisiae var. boulardii CNCM I-1079 (LEVUCELL SB) were also discussed.

Silva presented a trial conducted in Brazil using two different dosages. According to him, the benefits observed are linked to the probiotic effect on gut health. Interestingly he showed that, when using higher dosages of the probiotic yeast, the sows ate less than with the normal dose, but their performance was further improved, which he links to a higher effect on feed efficiency when using a higher dose.

Brewster also shared an Australian experience with LEVUCELL SB on finishing pigs during the summer. He explained that feeding pigs with a high energy diet is a common strategy in the summer. However, depending on raw material costs, this could be uneconomic at times. An experiment was conducted to evaluate the effect of the probiotic on finishing pigs' growth performance over the summer with either a low energy diet (high NDF) or a high energy diet (high starch). The data presented showed that LEVUCELL SB improves the growth performance and that the effect appears different between high and low energy diets. Brewster concluded that the probiotics improved FCR in any case, but to a higher extent with a high energy diet than low energy diet.

Finally, Yannig Le Treut, General Manager of Lallemand Animal Nutrition and a swine veterinarian, wrapped up the session by sharing new insights into the probiotics' modes of action. The information corroborated and provided greater understanding of the various trials presented. He showed results from a scientific trial conducted at INRA using metabolic chambers to study the modes of action of the probiotic yeast and its impact on energy metabolism and digestion. Le Treut reported how, until then, the positive effect of the live yeast on sows' energy metabolism was known but difficult to evaluate precisely. The study demonstrated what was hypothesized in field trials: the ability of the live yeast strain to increase energy retention of the animal, through the reduction of heat energy losses, enhancing performance. Interestingly, the probiotic supplement also improved the feeding behavior. The pigs showed a higher number of meals per day combined with a lower, and more stable, ingestion rate.

Reviewing various studies, Le Treut noted that - even though a lot still needs to be learned on the live yeast's modes of action in what he calls "a perfect fermenter" - its effects on the gut environment (e.g. oxygen scavenging) can lead to a 2.5-3% increase of net energy extraction from the diet. This is mainly due to 2 effects:

- Reduction of heat production energy losses
- Improved fiber degradation, which is corroborated with the latest studies on microbiota populations and activity.

In practice, this means that LEVUCELL SB's effect on the diet's net energy value can be taken into account. A valuable piece of information for the nutritionist to formulate cost-effective diets for dry sows.  

 
Dysbiosis in post-weaning piglet: State of microbial research

Dysbiosis is defined as a disequilibrium in the gut bacterial populations. When reviewing the latest scientific literature on this topic, Mathieu Castex, R&D Director at Lallemand Animal Nutrition, explained how post-weaning diarrhea in piglets is a dysbiosis issue. Weaning is a key period in pig production and there is a real necessity for the industry to seek non-antimicrobial alternative strategies to restore microbial balance and control gastro-intestinal infections associated with weaning in piglets.

Dr. Castex highlighted the importance of new technologies to understand the swine gut microbiota and microbial ecosystems:

- The development of in vitro models to limit experimental use of animals, such as the PigutIVM, aimed at re-creating the
conditions of a piglet intestine and the evolution of the microbiota population's interactions. This dynamic model already gave interesting insights into the effects of antibiotics and probiotics on the dynamics of microbial populations. For example, the positive effect of S. cerevisiae var. boulardii CNCM I-1079 on the decrease of E. coli levels using the model confirmed previous in vivo evidence. Today, scientists at Lallemand and INRA are looking to go one step further by including a mucosal phase in the model and study various dysbiosis scenarios and new ways to mitigate them. 

- The advancement of "omics" and high throughput sequencing techniques, which were then further developed by Caroline Achard, Research Scientist at Lallemand Animal Nutrition specialized in this topic.

Achard focused on the central roles of the microbiota in animal health and performance, which she qualified of "the forgotten organ," with metabolic, structural and protective functions, to which we can add the newer area of brain-gut communication. Achard reviewed the latest findings on piglet microbiota and how weaning in piglets and heat stress in finishing pigs can shape the gut microbiota and affect microbiota diversity. She shared the latest results obtained thanks to next generation sequencing techniques. Achard showed how weaning leads to drastic changes in microbiota composition, while thermal stress in adults brought more subtle changes.

Interestingly, in both cases, LEVUCELL SB supplementation affected the microbiota composition at different taxonomic levels. This showed the beneficial effects of the live yeast supplementation on performance of weaned piglets and heat-stressed finishing pigs may be, at least partially, mediated by the gut microbiota. Interestingly, Achard also showed some correlation between zootechnical performance, such as feed efficiency and certain bacterial species in the gut, which could be used in the future as predictive biomarkers for performance.

Finally, David Saornil, Product Manager at Lallemand Animal Nutrition, concluded the session by discussing nutritional strategies to reduce antimicrobial usage in post-weaning piglets, a key target for human and animal health worldwide. Post-weaning is the phase that uses the most antimicrobials in swine production, and, according to Saornil, strategies should start well in advance of this stage - including at the pre-farrowing sow. There are three pillars to antimicrobial reduction: management and environment, genetics and nutrition. Saornil reviewed the role of different factors that have a direct impact on gut health:

- Palatability and digestibility of the feed ingredients
- Use of creep feed
- Level of protein in the diets
- Inclusion of some specific raw materials such as spray-dried animal plasma
- Inclusion of certain levels and types of fiber to improve intestinal comfort
- Reduction of calcium concentration in the diet due to its high buffering capacity
- Inclusion of some feed additives with the aim of reducing the pressure of pathogens in the intestine or improving the integrity of the intestinal wall

Here, Saornil focused in particular on zinc oxide and its limitations (especially since the European Union has ruled out its use from 2022) as well as LEVUCELL SB effects. A recently published trial from Milan University, for example, indicated the probiotic effectiveness at partially replacing antimicrobials without affecting performance. Among the latest findings on the live yeast's modes of action, Saornil reports innovative findings showing the probiotic is modifying the genetic expression in the intestinal epithelium. In particular, it was found to up-regulate some genes related to intestinal integrity and nutrient transportation: a new piece in the LEVUCELL SB jigsaw!