Lactobacillus subtilis. The fermentation process is supposed to reduce or even eliminate the ANFs in soybean, and the final product would be more digestible and have a better nutritive value compared to conventional soybean. Indeed, the level of trypsin inhibitor, antigens and soy oligosaccharides has been found to be much lower in fermented soy compared with con- ventional soybean. Fermented soy is ranked in second place in terms of low ANFs among other soy products, just after soy pro- tein concentrate. However, one problem with fermented soy is that during the fermentation process, microbes convert soy pro- tein and amino acids into their own protein profile.
Enzyme-treated soy As the name suggests, enzyme-treated soy is a soy protein that is treated by enzymes (mostly a mixture of enzymes) to remove ANFs in soybean. Enzyme-treated soy is often being classified in the same group with fermented soy, which gives the wrong impression that the nutritive value of these two is the same. Using just the enzyme to remove ANFs, will not interfere with the protein and amino acid profile of soy, and will also guarantee that the quality of enzyme-treated soy between each batch is much more stable in comparison with fermented soy. For exam- ple, Danish manufacturer Agro Korn has produced AlphaSoy 530 from well-selected soybean meal, and gone through the strictly-controlled high thermal short time process (extrusion) with the fortification of enzymes to reduce ANFs and disrupt the complex structure of the seed matrix. The final product is then a gentle and balanced protein source (53% protein) that is highly digestible, suitable and very safe for the piglet’s digestive system.
Soy protein concentrate Soy protein concentrate is ranked as a premium soy protein source with a higher price tag than fermented soy and enzyme- treated soy. To achieve this high level of crude protein, the pro- duction of soy protein concentrate removes all the water- or alcohol-soluble non-protein components, and even the soluble carbohydrates through the extraction of dehulled and defatted soybean meal. This extraction process also removes most of the ANFs, especially oligosaccharides.
Figure 1 - Gain:Feed in newly weaned pigs fed enzyme-treated soy* vs. fishmeal. Source: Sørensen and Nørgaard, 2016.
1.0 0.83 0.8 0.6 0.4 0.2 5 0.0
Soy protein concentrate
Day 1-7 Fishmeal Day 7-14 Day 1-14 *AlphaSoy 530 *Means with a different letter are significantly different (P<0.05). PIGLETS - JULY/AUGUST 2016 13
Fermented soy 1
Day 6
Fermented soy 2
Day 33 AlphaSoy 530 0.83 0.74 0.74 0.77 0.77
Utilisation of soy protein in piglets Among soy products, enzyme–treated soy and soy protein con- centrate have higher metabolisable energy values than soybean meal. The Danish enzyme-treated soy product mentioned earlier (3937 kcal/kg) is also far superior in terms of ME value com- pared to fermented soy (3305–3635 kcal/kg). This is because of the extrusion process, and the enzyme treatment of the product that disrupt the rigid structure of the seed matrix and transform the fibre part as well as oligosaccharides to a more digestible form and consequently provide more energy to the animals. However, in fermented soy, microbes may consume all starch, sugar (sucrose) and oligosaccharides and even partly protein of soybean meal as energy sources for their growth during fermen- tation. This may explain why a lower ME value in fermented soy compared to soybean meal fed to weanling pigs has been observed (Rojas and Stein, 2014). In case of soy protein concen- trate, its high crude protein content also contributes to the diets as an energy source. In terms of growth performance, a study in weanling pigs proved that enzyme-treated soy is an outstanding protein source that can replace fishmeal completely while keeping up the increase in weight gain and an efficient feed conversion ratio (Figure 1) as well as good gastrointestinal health (Sørensen and Nørgaard, 2016). The positive effect of enzyme-treated soy on growth performance and diarrhoea after weaning is rather con- sistent in piglets in many studies; however, it is not the same in the case of fermented soy and soy protein concentrate. A new study of Harper Adams University observed that using 10% of enzyme-treated soy in the diets for weaned pigs led to the high- est daily weight gain compared to other soy products while the lowest one was in pigs fed soy protein concentrate (Figure 2). As the results suggest, the higher benefit margin over feed by €1-2 per pig was achieved in enzyme-treated soy compared with other soy products. Further studies are required to clarify the effect of various soy products on growth performance and gut health in piglets. Enzyme-treated soy, however, seems to be an alternative protein source that is the most consistent in quality and most economi- cal when replacing conventional high protein sources.
Figure 2 - Average daily gain of weaned pigs fed various soy protein. Source: Harper Adams University 2016. 578AB
105 205 305 405 505 605
566A 588AB
599B
267a
288ab
310ab
324b
PHOTO: SHUTTERSTOCK Gain: Feed
Average daily gain, g/day
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44
