Soybean is a forage used in swine feed that has important nutritional properties.

Soybean (Glycine max) is an oilseed that is widely used in animal nutrition for its nutritional properties. Soybeans can have about 40% crude protein, 20% fat, and 5% fiber. Soybean can be used in animal nutrition in two forms: as whole seed (unprocessed) or as soybean meal (a by-product obtained after extracting the oil from the seed). It is considered that at a nutritional level both forms provide enough nutrients, so one or the other is chosen depending on the economic capacity.

Soybeans are considered to have high agronomic requirements, so cultivation is limited to certain areas that can guarantee optimal conditions.

Soybean producing countries for animal nutrition

The top soybean-producing countries in 2019 were Brazil with 114 million tons, followed by the United States with 96 million tons and Argentina with 55 million tons. These three countries are estimated to produce about 80% of soybeans globally.

In fourth place is China with 15 million tons, in the fifth position in India with 13 million tons, and sixth is Paraguay with 8 million tons. Finally, the top 10 is closed by Canada with 6 million, Russia with 4 million, Ukraine with 3 million, and Bolivia with 3 million tons.

It is worth noting that in the TOP 10 soybean-producing countries worldwide, four Latin American countries contribute significant quantities of this raw material. For this reason, soybean is one of the most important export products for these countries.

World soybean production is low compared to other raw materials such as wheat and corn. However, in the last ten years, soybean production is estimated to have increased by 44%, from approximately 220 to 320 million tons.

Figure 2. Soybeans have important nutritional properties for swine feed.

Nutritional properties of soybeans

At the nutritional level, soybean meal contains a higher concentration of protein than the seed, with about 42 to 51%. In contrast, soybeans have more fat than soybean meal, at about 20%, and a lower protein value at about 38%.

Soybean is recognized in animal nutrition for being a forage that provides a high quantity of amino acids in the diet of animals, except for methionine. In pigs, methionine is considered the most important limiting amino acid, together with lysine and tryptophan. However, the quantity of the other amino acids makes soybeans an excellent nutritional choice.

In terms of energy, soybean contains a higher energy intake with about 4500 Kcal of digestible energy/kg, compared to soybean meal which provides 3800 Kcal of digestible energy/kg. As a result, growing and finishing pigs obtain an important source of metabolizable energy from soybeans, which they use for growth.

Soybean oils are rich in linoleic acid (18:2) with about 54% and linolenic acid (18:3). These compounds can change the characteristics of adipose tissue in pigs. Finally, the amount of minerals present in soybeans is shown in Tables 1 and 2.

Use of soybean in pigs

Soybean has been studied in swine feeding to obtain the best profile of this raw material in animal nutrition. It is recognized that the use of raw soybean is not recommended due to the antinutritional factors that seriously affect the development and health of the animals.

For this reason, the main sources of soybean used in pigs are meal and roasted or cooked whole seed. These products are subjected to heating processes that inactivate the anti-nutritional factors. Nevertheless, there are still drawbacks to this process since excessive heating can negatively alter the proteins.

However, the high protein levels in soybeans make them an attractive raw material for swine feed. These products are often combined with wheat and corn to supplement pig diets for optimal nutrient levels.

The protein digestibility coefficient of soybean protein in swine is estimated to be 85%. On the other hand, it is accepted that the maximum percentage of soybean incorporation in pig diets is 5% in weaning piglets (up to 28 days). In addition, the maximum in starter pigs (28-70 days) is 20%. In the case of fattening pigs, pregnant and lactating sows, there is no limit on the incorporation of soy in the diet.

Anti-nutritional factors of soybeans

Like other foods, soybeans have antinutritional factors that can be toxic to pigs. Some of these are trypsin inhibitors, Kunitz and Bowman-Birk factors, lectins, goitrogenic factors, hemagglutinins, vitamin A inhibitors. These anti-nutritional factors are present in raw soybeans and should never be used in this form to feed pigs.

Trypsin inhibitors influence protein metabolism in the small intestine, which directly impacts production performance. Pigs can have reduced daily weight gain, growth retardation, as well as pancreatic and liver lesions.

To avoid the effect of soybean anti-nutritional factors in pigs, the product must undergo industrial heating processes. In this way, the high temperatures inactivate the anti-nutritional factors and change the structure of the proteins so that they are better utilized by the pigs.

On the other hand, supplements that help digestibility can be used, as is the case of Alquerzim. This is a digestion optimizer for pigs and poultry that facilitates this process when using diets based on soy and other cereals. This Biovet S.A. product provides exogenous enzymes that facilitate the digestion of starch or excess protein in the diet. Enzymes are proteins that facilitate the digestion process of ingested food. In this way, digestibility is increased, and the animals take better advantage of the nutritional components of the soy-based feed.  On the other hand, administering Alquerzim reduces the possibility of intestinal disorders caused by enzymatic imbalances and undigested feed.

The price of soybeans

Soybeans are one of the world’s most important raw materials and are therefore a commodity of great importance for the international market.

In December 2021 the price of soybeans increased because of high world demand and climatic variations in Argentina, the largest producer. As a result, soybeans recently rose from USD 459 to USD 463 per ton on the Chicago exchange. In December, Argentina is expected to export 2.57 million tons and Brazil 2.8 million tons. One of the main destinations in China, as it is a major soybean importer. Another major importer will be the United States, whose domestic production has been affected by hurricane Ida.

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Conclusions

Animal feed has some high-quality raw materials such as soybeans. This product is recognized worldwide for having high values of protein, amino acids, and fatty acids.

Soybeans can be fed in the diet of pigs as whole grain (roasted or cooked) or as soybean meal, a by-product after the extraction of oil from the grain. Both products differ nutritionally but are of high nutritional value.

On the other hand, it is important to recognize that soybeans have anti-nutritional factors that can affect pig production and performance. Therefore, the grain must be subjected to industrial processes to inactivate them by heat. In addition, intestinal optimizers can be provided to facilitate the digestion of soybean components.

Finally, soybeans are a product of great value in the international market, which in recent weeks has increased its price. This has favored exports from Latin American countries such as Argentina and Brazil, which are among the largest soybean producers in the world.