FEED Business Worldwide - May, 2012
The contribution of phytogenics to pig nutrition
by Dr. Basharat SYED, BIOMIN Holding GmbH, Industriestrasse 21, 3130 Herzogenburg, Austria
Phytogenics are a group of natural growth promoters or non-antibiotic growth promoters, derived from herbs, spices or other plants consisting mainly of plant extracts, essential oils and their active principles. They are used in animal feeding to improve the performance of agricultural livestock.
This class of feed additives has gained increasing interest in the light of increasing concerns regarding the usage of antibiotic growth promoters in food animals. The active ingredients present in the phytogenic feed additives (PFA) reportedly improve growth, nutrient digestibility, gut health and thus economic benefits in pig production. These properties of the phytogenics project them as suitable alternatives to the antibiotic growth promoters.
The global pig industry is under extreme and growing pressure caused by price increases in raw materials for feed. At the same time, increasing demands in the area of environmental protection and clean air are threatening the sustainability of high welfare production and processing. Even temporary relief in the markets, among other things, by declining feed prices after a good grain harvest or higher pay-out rates for slaughtered pigs for a limited duration, should not lead the enterprises to a wrong assessment of the situation.
Feed price increases are a global phenomenon driven by global factors. Feed cost represents the biggest single cost in pig production. Currently it amounts to more than 45% of the production costs which is unsustainable for pig producers. Therefore, the aim is to decrease feed cost while increasing efficiencies. This improvement can be attained in different ways. Of course feed and farm management are on top of the list.
During times of high feed costs the saving potential through an improvement of feed utilisation is even more important. For example, optimising feed conversion by 0.1 with feed cost of €300/tonne will yield a benefit of €0.03/kg of weight gain.
With rising raw material expenses, it is understandable that in order to save costs the rations are divested of "unnecessary extras". Naturally, it is important to reconsider inputs but these must be reviewed in terms of their efficiency! The question is: Are the additives currently used in a cost-effective way?
In order to demonstrate; 1% less protein and a reduction of lysine by 0.05% in the diet will yield a saving of €6.0 to €7.5 per tonne of feed. However, in the worst case scenario this translates into a reduction of daily gain of approximately 12g, and therefore €1/pig.
Otherwise, it is well known that a reduction of 2% in crude protein in fattening will reduce nitrogen excretion by 20%.
One may ask if such a reduction (or perhaps even greater reductions) in crude protein can be achieved without decreasing performance? Indisputably the key lies in optimising the digestive process. Numerous research results are available for phytase, enzyme preparations and probiotic feed additives. It makes absolutely sense to reflect on what has been done for centuries in human nutrition to make food more digestible - use herbs and spices!
Would it be possible to ascribe this activity to animal nutrition and would it be possible to standardise such spice mixtures? The answer to both questions has been given in numerous experiments as well as in the commercial practice; the most efficient feed additives today are PFA.
The following overview of experimental trials and their results confirms the exemplary performance of a standardized, well documented PFA (Digestarom®). The main objectives of these trials included zoo-technical parameters (i.e. growth, feed conversion), animal health (reduction of mortality, incidence of diarrhoea), use of less digestible feed components, research in the area of immune response and extensive metabolism studies (ileal digestibility of nutrients and amino acids) with supplemental microbiological research on different sections of the intestine. Additional studies included the impact on meat quality and reduction of NH3 emissions. Following is a brief synopsis of some selected research results:
Use of less digestible raw materials
The influence of the PFA on the digestibility of the raw materials used was observed in a trial with modified diets for weaning piglets (Table 1). The difference between both basal diets was in the choice of protein sources. Diet 1 contained highly digestible components (i.e. soya, fish meal, blood meal), whereas diet 2 was based on less digestible components (i.e. lupines and rapeseed oil). In version C Digestarom® was added to the diet.
To illustrate the effect, a specific period was chosen between the 26th and 33rd day of life, during which time the body's own enzyme production is not yet fully developed. Figure 1 shows the development of live weight for the piglets within the different groups.
The effects are clear when comparing feed intake, growth, and protein expenditure per kg growth during the trial period in relative numbers (Control group A = 100%), as represented in Figure 2.
Comparing Group B to Group A, a significant dietary effect is observed in reference to growth and feed intake. The lower growth in group B is in essence a result of lower feed intake. Feed intake is readjusted by gastrointestinal and metabolic satiation signals in conjunction with the quality of available digestive enzymes. In direct comparison to Group B,
Group C has a higher feed intake, thus better development of body mass. This indicates that hindrance of the gastrointestinal and metabolic satiation signals, which led to a regression of feed intake in Group B, was suspended by the use of the PFA. This effect is clearly in evidence when comparing the feed conversion ratios (FCR). Group B showed a FCR of 1.60 while Group C demonstrated a FCR of 1.19.
Of particular interest is how the PFA effects the utilisation of nutrients, especially of proteins. The PFA group clearly showed a tendency towards better utilisation of proteins in the feedstuff. The higher growth in group C, with lower protein consumption per kg of weight gain is a clear indication of higher protein utilisation.
In addition to other features indicated in this trial, the PFA improved growth rate and optimised FCR as a result of higher metabolic protein transfer.
A conclusion can be drawn that with the beneficial effects of the phytogenic formula, less expensive feed components with lower protein content (i.e. less digestible components) can be considered in the diets with better profitability and ecological balance.
Brief resume of related investigations
Diarrhoeas are by far the most common cause of considerable losses in piglets. They can be the cause of more than half of all losses, especially in the suckling period. Additionally, the first two weeks after weaning are particularly regarded as critical. Diarrhoea is considered a classical multi-factorial disease, meaning that it is caused by the simultaneous action of various factors.
For the frequency and occurrence of diarrhoea besides viruses, bacteria and parasites as well as environmental factors such as nutrition, stress, stable climate, etc. play a major role. In numerous studies, it was proven that using complex phytogenic feed additives in the diet had a positive influence on the incidence of diarrhoea.
Studies at the University of Milan (Savoini et al. 2000) have shown that the use of the above-mentioned PFA in piglets orally infected with E. coli had shorter and lighter occurrences of diarrhoea compared to those supplied with antibiotics (Colistin and Carbadox). An interesting aspect of these results is that the zoo-technical performance of the animals supplied with the PFA did not lack behind the antibiotic group, despite significantly higher activation of the immune system.
Studies carried out at the Education and Research Institute Ruhlsdorf (Germany) revealed that the addition of the PFA in piglet diets reduced losses caused by oedema to below 25% in comparison to control pigs.
In an extensive research project conducted at the University of Khon Kaen in Thailand, a 50% reduction in the incidence of diarrhoea was detected in suckling piglets when the sow feed was supplemented with the PFA.
The effects presented above have so far been explained primarily from two aspects of the complex mode of action of Digestarom®, which is conclusively supported by scientific research. This phytogenic feed additive significantly improved the digestibility of feed ingredients, especially proteins (trial conducted at the Free University Berlin, Journal of Animal Science 89, 2011), resulting in less undigested nutrients available for harmful germs, thus inhibiting their proliferation. Furthermore, the alleviation of inflammatory processes on molecular-biological level has recently been documented in experiments carried out at the University of Giessen (Germany).
Another explanation is the influence that the PFA exerts on the formation and stability of the intestinal micro biota (Simon, 2009). The mode of action encourages the development of desired bacteria (among others lactobacilli) at the expense of potentially harmful bacteria (such as E. coli, C. perfringens). This ultimately results in a more stable physiological intestinal micro biota. By no means is this effect based on a direct antimicrobial impact (such as it is postulated for the classic antibiotic performance enhancers).
Phytogenics also have shown positive effects in growing-finishing pigs. In a trial with 180 fattening pigs at the Russian Academy of Agricultural Science, Kazan, a 6.7 % increase in growth performance and concurrently better protein utilisation was observed (Figure 3).
Conclusion
The above mentioned results and analysis lead to the following conclusions.
Supplementation of pig diets with the complex phytogenic feed additive Digestarom® resulted in a significant increase in protein digestibility, which is considered a main reason for improvements in feed conversion. Better nutrient utilization is a prerequisite for reduced manure production and consequently lower environmental emissions.
Through Digestarom®'s optimisation of the digestion process, a reduction in dietary energy (ME) content of about 0.2 MJ/48 kcal may be compensated without performance losses.
A concurrent reduction of diarrhoea problems is frequently observed in piglets (less undigested food in the intestines = less "feed" for harmful bacteria). This too has the effect of raising long-term animal performance.
Depending on actual prices in different countries, a highly positive return on investment (ROI) was achieved, indicating an excellent cost: benefit ratio for the use of the PFA in piglets and fattening pigs.
References are available upon request. For more information, please contact geraldine.tan@biomin.net
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