González-Vega

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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The site of absorption of calcium from the intestinal tract of growing pigs

González-Vega, J. C., C. L. Walk, and H. H. Stein. 2013. The site of absorption of calcium from the intestinal tract of growing pigs. J. Anim. Sci. 91(Suppl. 2):74 (Abstr.) Link to abstract (.pdf)

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Effects of using palm kernel expellers in phase 2 diets fed to weanling pigs

Palm kernel expellers is a coproduct of the production of palm kernel oil. Unlike palm kernel meal, which is produced after the oil is removed from the fruits of oil palms using solvent extraction, palm kernel expellers are produced via mechanical extraction. The lysine content of palm kernel expellers is low relative to soybean meal. Additionally, the high fiber content of palm kernel expellers means that it contains less digestible and metabolizable energy than soybean meal or corn. These factors limit the inclusion rate of palm kernel expellers in swine diets.  However, despite these limitations, palm kernel expellers can provide significant protein in swine diets and may be used to reduce feed costs.

An experiment was conducted to test the hypothesis that palm kernel expellers may replace some corn and soybean meal in phase 2 diets fed to weanling pigs without negatively affecting growth performance.

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Concentration of digestible and metabolizable energy and digestibility of energy in high protein canola meal, conventional canola meal, and soybean meal fed to growing pigs

Canola meal is the defatted meal that remains after oil has been extracted from the seeds of the rapeseed plant, Brassica napus.  Canola meal is high in crude protein and amino acids relative to most plant protein sources, and the amino acids in canola meal are well digested by pigs. However, it is also relatively high in fiber, which reduces energy digestibility and digestible energy concentration. New varieties of Brassica napus with a thinner seed coat have been hybridized, which contain less fiber and more protein than conventional rapeseed. The meal produced from these varieties is known as high protein canola meal. No data exist for the digestibility of energy in this source of high protein canola mealwhen fed to pigs. Therefore, an experiment was conducted to determine the apparent total tract digestibility (ATTD) of energy and the concentrations of digestible and metabolizable energy in two sources of high protein canola meal (CM-HP1 and CM-HP2) fed to growing pigs, and to compare these values with values for conventional canola meal (CM-CV) and soybean meal (SBM).

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Effects of using copra meal in phase 2 diets fed to weanling pigs

Copra meal is a coproduct of the production of coconut oil. Although the amino acid profile and digestibility in copra meal are less favorable than in soybean meal, it can provide significant protein and energy in swine diets and may be used to reduce feed costs.

An experiment was conducted to test the hypothesis that copra meal may replace some corn and soybean meal in phase 2 diets fed to weanling pigs without negatively affecting growth performance.

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Amino acid digestibility in canola, cottonseed, and sunflower products fed to finishing pigs

González-Vega, J. C. and H. H. Stein. 2012. Amino acid digestibility in canola, cottonseed, and sunflower products fed to finishing pigs. J. Anim. Sci. 90:4391:4400. Link to full text (.pdf)

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