Editor's Note
The current issue of the newsletter contains the following:
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A current comment on the correct use of microbial phytase in pig diets. -
Two research reports: one on amino acid digestibility in heat-damaged soybean meal, and one on energy content and phosphorus digestibility in three different whey products. -
A new publication from the Stein Monogastric Nutrition Laboratory.
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Sincerely,
Hans H Stein
Current Comment
Correct use of microbial phytase in diets fed to pigs
Microbial phytase is often used in diets fed to pigs because it is well established that the digestibility of phosphorus in many ingredients is increased if microbial phytase is used in the diet. The reason for this increase in digestibility is that microbial phytase has the ability to release some of the phosphorus that is bound in the phytate complex in many feed ingredients. Without phytase in the diet, most of the phytate-bound phosphorus is not digested by the pigs and is instead excreted in the manure.
Research Reports
Amino acid digestibility in heated soybean meal fed to growing pigs
Soybean meal fed to pigs undergoes heat treatment to destroy trypsin inhibitors and other antinutritional factors that impair the digestion of protein and thus reduce performance. However, heat treatment can damage nutrients as well. In particular, the Maillard reaction reduces amino acid digestibility by combining amino acids with sugars to produce biologically unavailable compounds.
An experiment was conducted to determine the digestibility of amino acids in pigs fed soybean meal that had been heat treated in varying ways and for varying times. Conventional soybean meal was divided into four batches. One batch was not heated; one was autoclaved at 125°C for 15 minutes; one was autoclaved at 125°C for 30 minutes; and the last one was oven dried at 125°C for 30 minutes. Ten growing barrows were fed a total of five different diets. The experimental diets contained 40% each of the four different soybean meals being tested. An N-free diet was also formulated and fed to measure the basal endogenous loss of protein and amino acids.
Whey powder is a co-product of the cheese industry, and consists primarily of lactose and protein. The inclusion of whey powder in weanling pig diets improve growth performance; this is believed to be due to the lactose fraction. Because of the demand for whey protein from the human food industry, the protein is sometimes extracted from whey powder. The resulting product is called whey permeate.
Few values for digestible and metabolizable energy in whey permeate have been reported. In addition, the standardized total tract digestibility (STTD) of phosphorus in these ingredients has not been reported. Therefore, two experiments were conducted: the first, to determine the concentrations of digestible and metabolizable energy in whey powder, whey permeate, and low-ash whey permeate; and the second, to determine the apparent and standardized total tract digestibility of phosphorus in the same ingredients.
Publication
Almeida, F. N., G. I. Petersen, and H. H. Stein. 2011. Digestibility of amino acids in corn, corn coproducts, and bakery meal fed to growing pigs. J. Anim. Sci. 89:4109-4115.