Soybeans

Other Names: Full-fat soybeans Nutritional Characteristics:

Soybeans provide an excellent source of both energy and protein for poultry. As with any ingredient, their usage rate depends upon economics, although in the case of soybeans such economics relate to the relative price of soybean meal and of supplemental fats. Soybeans contain about 38% crude protein, and around 20% oil.

Comparable to the manufacture of soybean meal, soybeans must be heat processed in some way to destroy the trypsin inhibitors and to improve overall protein digestibility. Feeding raw soybeans or improperly processed soybeans will cause poor growth rate or reduced egg production and egg size. If processing conditions are suspect, the birds' pancreas should be examined, because if trypsin inhibitors are still present pancreas size can be expected to increase by 50-100%. While processed beans should be periodically tested for trypsin inhibitor or urease levels, a simple on-going test is to taste the beans. Under-heated beans have a characteristic 'nutty' taste, while over-heated beans have a much darker color and a burnt taste. The problem with overheating is potential destruction of lysine and other heat-sensitive amino acids.

Heat-treated soybeans can be easily ground in a hammer mill, even though they are high in fat, and the ground product is a relatively free-flowing material. Because of the high oil content, ground beans should not be stored for any length of time due to potential for oxidative rancidity. However, it is important that beans be well ground because it is necessary to release fat from the plant cells in order to aid digestion. Coarsely ground beans have lower fat digestibility than do more finely ground material. Heating beans by whatever means usually results in considerable 'shrinkage' which is mainly due to loss of water. In many situations, shrinkage will be up to 7%, but of this, less than 1% will be real loss of dry matter.

Recently there has been growing interest in processing beans through extruders or expanders. The heat necessary to destroy trypsin inhibitors and other hemagglutinins found in raw beans is dependent upon exposure time, and so high temperatures for a shorter time period are as effective as lower temperatures for longer times. Because both expanders and extruders are fast throughput, the beans have a relatively short dwell time in the conditioning chamber. Consequently, slightly higher temperatures are necessary, and depending upon design, such machines are best operated at 140-155°C. Again, the effectiveness of expanding and extrusion can be measured by tests for urease and available lysine content.

Potential Problems:

Under-heating of soybeans is detected as a high urease or KOH protein solubility. If broiler finisher diets contain > 30% soybeans, then their body fat will become less saturated and more prone to oxidative rancidity. This latter problem can be resolved to some extent by using higher levels of vitamin E (75-100 lU/kg).

Pregnancy Diet Plan

Pregnancy Diet Plan

The first trimester is very important for the mother and the baby. For most women it is common to find out about their pregnancy after they have missed their menstrual cycle. Since, not all women note their menstrual cycle and dates of intercourse, it may cause slight confusion about the exact date of conception. That is why most women find out that they are pregnant only after one month of pregnancy.

Get My Free Ebook


Post a comment