Adisseo: Increasing Digestibility In Pigs To Capture Full Value Of Feed

The effect of high-fibre ingestion has usually been reduced pig growth rate. However, the reports obtained have often been contradictory. Fibres consist of various components (Figure 1).

The synthesis of internal and published studies has been performed (Figure 2), showing the detrimental effect of fibre evaluated as neutral detergent fibre (NDF; part of dietary fibres) - on growing pigs and piglets.

This synthesis demonstrates a negative correlation between NDF and performance. It also suggests a more detrimental effect on pigs compared to piglets.

Within NDF, arabinoxylans (AX) are the  most represented NSPs in the main cereals and by-products commonly used in swine feed. Digestible energy and amino acid digestibility are highly correlated with the level of arabinoxylans in feed: the higher the level of arabinoxylans, the lower the energy and amino acid digestibility (Figure 3).

Arabinoxylans decrease fecal digestibility by 1% and ileal digestibility by 0,6% for every 10g/kg of total AX. These values suggested a similar effect of ANF on amino acid and digestibility.

Exploiting enzymatic action requires understanding the content and structure of indigestible fractions and anti-nutritional factors in feed ingredients. It is the first step to predict optimal enzyme effect.

Enzymes used in feed should match specific substrates found. Factors to be considered when choosing an enzyme solution to achieve optimal results may include:

    ►  Dietary NSP concentration and quality (like arabinoxylans and their soluble and insoluble fraction);

    ►  Phytate level.

When choosing an enzyme solution, understanding all diet substrates and antinutritional factors present in the feed will help make the best choice.

Attention should be given to the combination of multiple enzymes and debranching enzymes in addition to their kinetic and pH profiles (favouring a multienzyme solution that is active across a wide pH range with broad substrate specificity). A fribrinolytic enzyme might be applied for phytase.

Fibre's detrimental effect might be considered the same for all nutrients. Consequently, fibre hydrolysis increases the digestibility of all nutrients in the same way.

A combination of several exogenous enzymes should be approached as a unique enzyme solution. Together, they attack antinutritional factors found in each combination of raw materials, releasing nutrients from them. This principle is known as the Feedase approach.

To demonstrate the synergistic effect of different enzymes on growing pigs' performance, a multi-carbohydrase was added to highly concentrated phytase, creating a multi-carbohydrase plus phytase complex (MCPC; Rovabio Advance Phy, Adisseo).

A study evaluated the effect of MPCP on grower-finisher pigs' performance. Overall, 276 Lance-Large White female × Duroc male hybrid pigs were part of the trial, which was carried out at the Swine Education and Research Facility, South Dakota State University (US).

The experiment followed a complete randomised design, with five dietary treatments, nine replicates and six or seven pigs per replicate. Five typical American corn-wheat-soybean-meal-based diets were formulated as follows:

    ►  PC: NE and nutrients specification based on NRC 2012 recommendations;

    ►  NC: -5% NE, -5% digAA, -0.134% unit digP, -0.119% unit Ca;

    ►  NC + Rovabio^® Advance Phy.

Over the whole growth period (34-120kg body weight), pigs fed either of the unsupplemented negative control diets had weaker performance than the positive control. Adding the MCPC to both negative control diets improved performance. Figure 4 shows that the gain-to-feed ratio reached the same level as the positive control. This data demonstrates that adding MCPC can recover performance loss when feeding lower specification diets. The reduction in nutrient levels saved €20/t of feed, compared to the positive control. This equates to a saving of €4.50 per pig.

Feedase improves the precision of formulation recommendations for the whole enzyme complex added to feed. It contributes to lower use of phosphorus and nitrogen resources and decreased nutrient waste while achieving excellent animal performance.

Better performance could be explained by an increase in the apparent total tract digestibility (ATTD) of dry matter, gross energy, crude protein and phosphorus (Figure 5). This means that the NE and dig AA can both be lowered by 5%, together with a reduction of 0.134 % unit of dig. P, and 0.114 % unit of Ca, in pig diets – without any negative effects on growth performance or bone ash (Figure 6).

Conclusion

Using a MCPC (with its recommendation for use developed under Feedase) can deliver improved performance at a lower cost, or decrease feed cost while maintaining animal performance.

Tools like PNE and Predictor should also be used for substrate evaluation and the prediction of feed matrix values, respectively.

Using a multi-carbohydrase plus phytase complex can deliver improved performance at a lower cost, or decrease feed cost while maintaining animal performance.