González-Vega

Effects of microbial phytase on apparent and standardized total tract digestibility of calcium in feed ingredients of animal origin

Most swine diets must be supplemented with calcium because most plant ingredients commonly used in diets for pigs contain relatively little calcium. One way to add calcium is to include inorganic sources such as dicalcium phosphate or calcium carbonate; however, animal ingredients such as meat byproduct meals can also be used. These ingredients, often used as a protein source, are also a good source of calcium. To our knowledge, values for apparent (ATTD) and standardized (STTD) total tract digestibility of calcium in animal sources have not been reported. Therefore, an experiment was conducted to determine the ATTD and STTD of calcium in four calcium sources of animal origin.

The secondary objective of the study was to test the hypothesis that the addition of microbial phytase to diets containing calcium sources of animal origin would increase the digestibility of calcium. Although animal sources do not contain phytate, swine diets are composed primarily of plant ingredients, and the phytate in those ingredients might form complexes with the calcium in the animal sources.

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Concentrations of digestible, metabolizable, and net energy in soybean meal produced in different areas of the United States and fed to pigs

Sotak-Peper, K. M., J. C. González-Vega, and H. H. Stein. 2015. Concentrations of digestible, metabolizable, and net energy in soybean meal produced in different areas of the United States and fed to pigs. J. Anim. Sci. 93:5694-5701. Link to full text (.pdf)

Digestible calcium requirements for 25 to 50 kg pigs

González-Vega, J. C., C. L. Walk, and H. H. Stein. 2015. Digestible calcium requirements for 25 to 50 kg pigs. Memorias XVII Congreso Bienal AMENA. Puerto Vallarta, Jal. Mexico. Link to full text (.pdf)

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Effect of phytate, microbial phytase, fiber, and soybean oil on calculated values for apparent and standardized total tract digestibility of calcium and apparent total tract digestibility of phosphorus in fish meal fed to growing pigs

González-Vega, J. C., C. L. Walk, and H. H. Stein. 2015. Effect of phytate, microbial phytase, fiber, and soybean oil on calculated values for apparent and standardized total tract digestibility of calcium and apparent total tract digestibility of phosphorus in fish meal fed to growing pigs. J. Anim. Sci. 93:4808-4818. Link to full text (.pdf)

Calcium balance at different levels of digestible calcium and digestible phosphorus in weanling pigs

Recent studies conducted in our laboratory have determined values for standardized total tract digestibility (STTD) of calcium in feed ingredients fed to pigs. However, there is a lack of information about the requirement for STTD calcium in diets for pigs. Therefore, an experiment was conducted to measure calcium balance at different levels of STTD calcium in diets fed to 11 to 25 kg pigs.

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Growth performance and bone mineralization in weanling pigs fed diets containing different levels of digestible calcium and digestible phosphorus

It is important to include calcium and phosphorus in the diets in the proper proportions because the excess or deficiency of one mineral may affect the utilization of the other. Calcium requirements in the 2012 NRC are based on a model, which used a 2.15 ratio of total calcium to standardized total tract digestible (STTD) phosphorus. An optimal ratio of STTD calcium to STTD phosphorus has not been reported because not enough data exist on the standardized total tract digestibility of calcium. However, recent studies conducted by the Stein Monogastric Nutrition Lab have determined values for STTD calcium for several calcium sources. With these data, it is possible to determine the requirement for STTD calcium. Therefore, an experiment was conducted to determine the requirement of STTD calcium to maximize growth performance and bone ash in 11 to 25 kg pigs.

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Effects of microbial phytase on apparent and standardized total tract digestibility of calcium in calcium supplements fed to growing pigs

González-Vega, J. C., C. L. Walk, and H. H. Stein. 2015. Effects of microbial phytase on apparent and standardized total tract digestibility of calcium in calcium supplements fed to growing pigs. J. Anim. Sci. 93:2255-2264. Link to full text (.pdf)

Energy concentration and amino acid digestibility in high-protein canola meal, conventional canola meal, and soybean meal fed to growing pigs

Berrocoso, J. D., O. J. Rojas, Y. Liu, J. Shoulders, J. C. González-Vega, and H. H. Stein. 2015. Energy concentration and amino acid digestibility in high-protein canola meal, conventional canola meal, and soybean meal fed to growing pigs. J. Anim. Sci. 93:2208-2217. Link to full text (.pdf)

Digestible calcium requirements and calcium and phosphorus balance for weanling pigs

González-Vega, J. C., C. L. Walk, and H. H. Stein. 2015. Digestible calcium requirements and calcium and phosphorus balance for weanling pigs. J. Anim. Sci. 93(Suppl. 2):51-52 (Abstr.) Link to abstract (.pdf)

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Effect of fiber and fat on calculated values for standardized total tract digestibility of calcium in fish meal

González-Vega, J. C., C. L. Walk, and H. H. Stein. 2014. Effect of fiber and fat on calculated values for standardized total tract digestibility of calcium in fish meal. J. Anim. Sci 92(E-Suppl. 2):231-232 (Abstr.) Link to abstract (.pdf)

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Effect of phytase, fiber, and fat on calculated values for apparent and standardized total tract digestibility of calcium in fish meal

The presence of phytate in swine diets reduces the digestibility of calcium because phytate is able to bind calcium from organic sources and some inorganic sources, making it inaccessible to the pig. Microbial phytase breaks down phytate and increases the availability of calcium. An experiment was conducted to test the hypothesis that inclusion of microbial phytase increases the apparent (ATTD) and standardized (STTD) total tract digestibility of calcium in fish meal in diets containing phytate from corn and corn germ.

Besides phytate, corn and corn germ also add fiber and fat to diets, so it is important to know how fiber and fat affect calcium digestibility. Therefore, a second experiment was conducted to test the hypothesis that the values of ATTD and STTD of calcium obtained from cornstarch and corn based diets may differ, and to determine the effect of dietary fiber and fat on the ATTD and STTD of calcium in fish meal.

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Effects of microbial phytase on apparent and standardized total tract digestibility of calcium in calcium supplements fed to growing pigs

Calcium supplementation is important for swine diets because most commonly used feed ingredients have low concentrations of calcium. In a typical corn-soybean meal diet for a growing pig, the corn and soybean meal contribute only about 16% of the total calcium, with the rest coming from supplements. Apparent total tract digestibility (ATTD) values for calcium have not been reported for many common ingredients, and no values for the standardized total tract digestibility (STTD) of calcium have been reported. Therefore, an experiment was conducted to determine the ATTD and STTD of calcium in five calcium supplements.

An additional objective was to test the hypothesis that inclusion of microbial phytase in the diets increases the ATTD and STTD of calcium. Results of previous research has indicated that inclusion of microbial phytase in swine diets often increases the digestibility of calcium, but the effect of phytase on the STTD of calcium in individual ingredients has not been reported.

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Effects of microbial phytase on apparent and standardized total tract digestibility of calcium in calcium supplements fed to growing pigs

González-Vega, J. C., C. L. Walk, and H. H. Stein. 2014. Effects of microbial phytase on apparent and standardized total tract digestibility of calcium in calcium supplements fed to growing pigs. J. Anim. Sci. 92(Suppl. 2):36 (Abstr.) Link to abstract (.pdf)

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Effects of using copra meal, palm kernel expellers, or palm kernel meal in diets for weanling pigs

Jaworski, N. W., J. Shoulders, J. C. González-Vega, and H. H. Stein. 2014. Effects of using copra meal, palm kernel expellers, or palm kernel meal in diets for weanling pigs. Prof. Anim. Sci. 30:243-251. Link to full text (.pdf)

The site of net absorption of Ca from the intestinal tract of growing pigs and effect of phytic acid, Ca level and Ca source on Ca digestibility

González-Vega, J. C., C. L. Walk, Y. Liu, and H. H. Stein. 2014. The site of net absorption of Ca from the intestinal tract of growing pigs and effect of phytic acid, Ca level and Ca source on Ca digestibility. Arch. Anim. Nutr. 68:126-142. Link to full text (.pdf)

Calcium digestibility and metabolism in pigs (Invited review)

González-Vega, J. C., and H. H. Stein. 2014. Calcium digestibility and metabolism in pigs (Invited review). Asian-Austr. J. Anim. Sci. 27: 1-9. Link to full text (.pdf)

Energy concentration and phosphorus digestibility in canola, cottonseed, and sunflower products fed to growing pigs

Rodríguez, D. A., R. C. Sulabo, J. C. González-Vega, and H. H. Stein. 2013. Energy concentration and phosphorus digestibility in canola, cottonseed, and sunflower products fed to growing pigs. Can. J. Anim. Sci. 93:493-503. Link to full text (.pdf)

Determination of endogenous intestinal losses of calcium and true total tract digestibility of calcium in canola meal fed to growing pigs

González-Vega, J. C., C. L. Walk, Y. Liu, and H. H. Stein. 2013. Determination of endogenous intestinal losses of calcium and true total tract digestibility of calcium in canola meal fed to growing pigs. J. Anim. Sci. 91:4807-4816. Link to full text (.pdf)

Growth performance of weanling pigs fed diets containing copra meal, palm kernel expellers, or palm kernel meal

Jaworski, N. W., J. C. González-Vega, and H. H. Stein. 2013. Growth performance of weanling pigs fed diets containing copra meal, palm kernel expellers, or palm kernel meal. J. Anim. Sci 91(E-Suppl. 2):706 (Abstr.) Link to abstract

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Energy concentration and phosphorus digestibility in canola, cottonseed, and sunflower products fed to growing pigs

Rodríguez, D. A., R. C. Sulabo, J. C. González-Vega, and H. H. Stein. 2013. Energy concentration and phosphorus digestibility in canola, cottonseed, and sunflower products fed to growing pigs. J. Anim. Sci. 91(Suppl. 2):116-117 (Abstr.) Link to abstract (.pdf)

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