Lallemand’s hydrolysed yeast: Unmatched protein digestibility kinetics

Why look at protein absorption kinetics?

Protein digestibility of feed materials is important information for nutritionists, but it does not include timing of absorption in the gut. The kinetics of protein absorption should be considered, too. It allows us to properly assess the quality of the protein source. Many properties and functionalities of proteins are related to their absorption kinetics. The kinetics of protein absorption helps categorise the protein fraction according to its speed of absorption. Four categories can be defined as flash, fast, slow and resistant along the digestive tract (Figure 1).

Figure 1- Kinetics of protein absorption: key parameters for protein functionalities.

Supplying animals with flash and fast digestible protein sources rich in free amino acids and small peptides will help them absorb and use those nutrients easily, and thus support animal performance, digestive health and feed appetibility while contributing to the feed-protein balance. This is particularly of interest when applied to the diets of young animals as their digestive tract is not yet mature.

Hydrolysed yeast offers highly digestible and quickly absorbed proteins

Yeast is an incredible bioengineering factory and a source of valuable nutrients and functional molecules. Yela ProSecure is a specifically designed hydrolysed yeast born from Lallemand’s extensive yeast expertise.

Yela ProSecure’s kinetics of protein absorption have been analysed with the Boisen method (Figure 2). Yela ProSecure’s protein digestibility starts at 77% at the beginning of the intestinal phase (right after the stomach) and increases to 94% after 48 hours. Moreover, the product is close to its maximum in vitro digestibility after three hours of intestinal digestion, meaning that 90.5% of the protein content of the product has flash and fast digestibility kinetics. The proteins from Yela ProSecure are, therefore, highly bioavailable for the animals.

Figure 2- Yela ProSecure: kinetics of protein digestibility.

Kinetics of protein absorption compared to other feed materials

Based on the Boisen method, 8 feed materials were assessed for protein digestibility and kinetics of absorption (Figure 3):

• Whey protein concentrate (WPC) has a flash protein digestibility. Nevertheless, the crude protein content is low (35%), the volume may be limited and price can be high.
• Blood plasma starts with 61% protein digestibility after passing through the stomach and is close to 100% after one hour 30 minutes in the intestine.
• Soybean meal starts with a 50% protein digestibility after passing through the stomach and increases up to 70% after three hours in the intestinal phase.
• The kinetics of protein digestibility for fish meal is between Yela ProSecure and soybean meal.
• Soy protein concentrate (SPC) reaches the same protein digestibility as soybean meal after three hours but starts with a lower digestibility after the stomach.
• The kinetics of protein digestibility for the whole cell inactivated yeast is between SPC and potato protein concentrate.
• Potato protein concentrate appears to have a lower digestibility after the stomach (40%) and slower kinetics of protein digestibility over time.

Figure 3- Kinetics of protein digestibility of various protein sources.

Compared to these feed materials, the hydrolysed yeast product shows interesting kinetics of protein digestibility thanks to its well-controlled hydrolysis process, which makes the protein highly available and quickly absorbed. One direct result of that is a negligeable amount of non-digested protein reaching the lower gut.

Application to piglets around weaning

In this high growth period, the synthesis and protein content in the gut is increasing at the same time as an important amino acid metabolism reshaping is happening. The requirement in arginine increases and the risk of shortage is real.

The systemic inflammation and associated infections sometimes related to the weaning lead to an increase in tryptophane, cystine and methionine as well as threonine.

At the same time, piglet diets evolve toward a reduction of the crude protein content, with the producer’s goal of maintaining animal growth performance. To achieve this goal, it is crucial to use highly digestible protein sources, which help reduce the crude protein content of the diet while maintaining the digestible protein levels associated with high functionalities for the animal.

Nutritionists are looking for highly digestible protein sources with fast kinetics of protein absorption, which supply free primary and secondary amino acids.

The hydrolysed yeast product from Lallemand helps manage dietary amino acids to optimise intestinal homeostasis, which is essential during stressful periods.

Conclusion

Hydrolysed yeasts are a promising and innovative functional protein source to consider, mainly driven by the free amino acids and the small peptides obtained from the cracking process of the protein. When the hydrolysis process is controlled, yeast bring a standardised profile of free amino acids, which plays a positive role in the maintenance of animal gut health, contributing to the feed protein balance and enhancing feed appetibility.