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When BSE, or mad cow disease, appeared there was a great revolution both at a social as well as at a nutritional level. Suddenly and unjustly, the use of fish meal for ruminants was banned by law. Currently the use of this prime matter is only allowed in the alimentation of non-ruminant animals in plants that do not manufacture feed for ruminants.
Given this situation the alternatives to fish were studied more deeply, and there was an important development in vegetable concentrates (soya, potato, wheat) as well as in products coming from pig intestines.
The vegetable concentrates, principally soya and potato, are alternative sources to the protein originating from animals. In general vegetable concentrates are obtained by complex extraction and/or fermentation processes which adds a great deal to their cost. In the production process of soya protein concentrates there is an attempt to eliminate the thermostable antinutritional factors presents in soya such as oligosaccharides (raffinose and estachiose) and antigenic proteins. This makes the product more digestible and less dangerous when incorporated into the food of the youngest piglets. There is a great variety of products on the market, with differences in protein content (from 50% to 65%) and differences in digestibility (85-89%) and prices.
Soya concentrates have a large share of the market as the price is very competitive and the quality is always improving, both in homogeneity and in the level of antinutritional factors.
On the other hand, the inclusion of sources other than soya is recommendable, in order to increase the variability of protein origins in the formula. One of the available options is potato concentrates. After extracting the starch from the potato there remains a protein extract of very high quality. This extract is submitted to some thermal treatments to eliminate an alkaloid, solanine, which has a bitter taste and decreases the palatability, thus also improving digestibility. The inclusion of solanine content in the alimentation of piglets is limited to a máximum of 1-2%. Currently there are products being commercialized that have solanine levels reduced to a minimum thus producing protein concentrates of a higher quality. In these cases, the level of inclusion in piglet feed can be raised up to 5% without problems, with 80% brute protein and digestibility of more than 90%. However, there is a high demand for potato protein which leads to price increases of up to 30%. The annual fluctuation can also be affected by the price of other prime matter such as wheys and skimmed milks.
In general, the quality, homogenity and efficiency of protein products have improved, the potato above all, with a very good nutritional value, both for the protein content as well as for the aminoacidic level. It is also worth mentioning the protein concentrates starting with cereals, especially wheat and rice, as well as the new development from biocarbonates. These products generally have a worse quality/price ratio than fish as far as the aminoacidic profile is concerned.
Products derived from brewers yeast have also been developed, produced drying yeast in a spray tower. This is a protein concentrate with a relatively low concentration, around 50%, but with a very competitive price compared to the others, and it is occasionally interesting with respect to other soya concentrates. Another interesting aspect is its content of group B vitamins, while the main disadvantage is its low palatability for the youngest piglets, and it is not recommended to include more than 2.5 or 4% in prestarter and starter, respectively.
The development of products deriving from pig intestine makes both the production and sanitary results more than satisfactory, in some cases improving on fish, even in the palatability of the feed. The pig intestine peptides are a by-product of heparin production, and therefore they have high controls of quality and production. A high percentage of protein is in the form of peptides which increase the digestibility of the product. Moreover, the increase in consumption is superior to vegetable sources, and is similar to the consumption of fish diets. The level of brute protein is 50% and digestibility is above 95%. The price is competitive when compared to other sources both animal and vegetable. The improvement over the last year in production technology has brought down the sodium levels which limited its inclusion in piglet formula. An important advantage is that it is not necessary to have two lines of production for the use of this prime matter, since it is suitable for all species.
In short, we could make the following classification* when the time comes to decide on an alternative to fish meal:
| By price: |
| 1. Soya concentrates |
| 2. Intestine peptides |
| 3. Brewers yeast concentrate |
| 4. Potato concentrates |
| 5. Cereal concentrates |
| By results: |
| 1. Intestine peptides |
| 2. Potato concentrates |
| 3. Soya concentrates |
| 4. Brewers yeast concentrate |
| 5. Cereal concentrates |
| By availability: |
| 1. Soya concentrates |
| 2. Intestine peptides |
| 3. Brewers yeast concentrate |
| 4. Cereal concentrates |
| 5. Potato concentrates |
(*) depending on current market conditions
