Stein

Crystalline amino acids in diets used to determine the standardized ileal digestibility of amino acids in feed ingredients fed to pigs do not influence calculated values for amino acid digestibility

Protein and amino acids quality in feed ingredient is most correctly evaluated by determining the standardized ileal digestibility (SID) of crude protein (CP) and amino acids. Experiments to determine the SID of CP and amino acids in feed ingredients often utilize semi-synthetic diets that contain the test ingredient as the sole source of CP and amino acids. Therefore, the CP and amino acid supply from experimental diets do not always meet the requirement for standardized ileal digestible amino acids by pigs and, therefore, pig growth is often limited in these experiments.

Crystalline amino acids are believed to be rapidly absorbed and 100% digestible. Addition of crystalline amino acids to diets during the adaptation or collection phase is, therefore, believed not to influence values for SID of amino acids in the test feed ingredient, but this has not been experimentally verified. Therefore, an experiment was conducted to test the hypothesis that addition of crystalline amino acids to diets during the adaptation or collection periods of digestibility studies will not influence calculated values for SID of CP and amino acids in corn and soybean meal. 

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Influence of the concentration of dietary digestible calcium on growth performance, bone ash, and abundance of genes involved in intestinal absorption of calcium in pigs from 11 to 25 kg fed diets with different concentrations of digestible phosphorus

Requirements for P for growing pigs are expressed as the requirement for standardized total tract digestible (STTD) P, whereas requirements for Ca are usually expressed as requirements for total Ca. It is, however, recognized that diets for pigs are most accurately formulated based on a STTD Ca:STTD P ratio, and recent work has generated values for STTD of Ca in most Ca containing feed ingredients, which makes it possible to formulate diets based on STTD Ca.

Recent data from the University of Illinois have indicated that if STTD P is at the requirement, a ratio between STTD Ca and STTD P that is less than 1.35:1, 1.25:1, and 1.10:1 maximizes growth performance of pigs from 25 to 50 kg, 50 to 85 kg, and 100 to 130 kg, respectively. However, the STTD Ca:STTD P ratio needed to maximize bone ash is greater than the ratio needed to maximize growth performance. An attempt to estimate the requirement for STTD Ca by pigs from 11 to 25 kg was also made, but due to a reduction in ADG and G:F as dietary Ca increased, an optimal STTD Ca:STTD P ratio could not be estimated.

Calcium may be absorbed by transcellular or paracellular transport. Transcellular transport is the primary route if dietary Ca is low, but if dietary Ca is adequate or high, Ca is mainly absorbed using the paracellular route via the tight junctions. However, there are limited data demonstrating effects of dietary Ca concentration on abundance of genes related to transcellular and paracellular transport of Ca in the small intestine of pigs.

Therefore, the objectives of this experiment were to test the hypotheses that a STTD Ca:STTD P ratio less than 1.40:1 maximizes growth performance of pigs from 11 to 25 kg and that increasing dietary Ca downregulates abundance of genes related to transcellular absorption of Ca and tight junction proteins in the small intestine.

 

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Effect of dietary calcium on growth performance of growing pigs

S. A. Lee, Vanessa Lagos, and Hans H. Stein. 2018. Effect of dietary calcium on growth performance of growing pigs. Pages 173 - 184. XXXIV Specialization Course FEDNA, Madrid, Nov. 22 - 23, 2018. Link to full text (.pdf)

 

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Nutritional value of high-lysine sorghum, red sorghum, white sorghum, and yellow dent corn fed to growing pigs

Sorghum is used as an alternative to corn due to its lower cost and wide availability. However, conventional sorghum contains high concentration of tannin and phytate, which act as antinutritional factors. Use of microbial phytase may hydrolyze phytate and subsequently improve P absorption. High-lysine sorghum is a new variety of sorghum which may be comparable to other cereal grains and may serve as alternative to corn for pigs. However, there are at this point no data for effects of adding phytase to diets containing sorghum and no data to demonstrate the nutritional value of high-lysine sorghum.

Therefore, 2 experiments were conducted to test the hypothesis that inclusion of 500 phytase units (FTU)/kg of microbial phytase improves the standardized total tract digestibility (STTD) of P in sorghum varieties. The second hypothesis was that the STTD of P, as well as concentrations of digestible energy (DE) and metabolizable energy (ME) in high-lysine sorghum is not different from that of corn and other sources of sorghum.

 

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Effects of dietary leucine concentration on branched-chain amino acid metabolism in growing pigs

Leucine, Val, and Ile are categorized as the branched-chain AA (BCAA) because of the structural similarity of their side chains. All 3 BCAA share the enzymes that are involved in the first 2 steps of their catabolic pathway. The first step is a transamination step catalyzed by BCAA transaminase (BCAT) and producing branched-chain α-keto acids (BCKA). The second step is an irreversible degradation step catalyzed by branched-chain α-keto acid dehydrogenase (BCKDH). In the second step, Leu has been considered a key regulator as its BCKA metabolite (α-keto isocaproate) stimulates activation of the BCKDH complex in the liver. When excess Leu in diets is offered to pigs, degradation of all 3 BCAA may increase because of increased activity of BCAT and BCKDH. Leucine and Trp are both categorized as large neutral AA, and they share a common uptake pathway across the blood-brain barrier. Therefore, it is possible that excessive Leu may result in reduced Trp uptake into the brain due to competition for transporters, resulting in reduced serotonin synthesis.

 

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Basal endogenous loss, standardized total tract digestibility, and retention of calcium in gestating sows changes during gestation, but microbial phytase reduces basal endogenous loss of calcium by gestating sows

Standardized total tract digestibility (STTD) of Ca has been determined for most Ca containing ingredients fed to growing pigs, but the basal endogenous loss of Ca is greater and the STTD of Ca in sows in mid-gestation are less than in growing pigs. As a consequence, if diets for gestating sows are formulated using STTD values determined in growing pigs, the provisions of digestible Ca may be less than anticipated.

The efficacy of phytase to release Ca and P is believed to be influenced by the physiological state of pigs with phytase fed to sows in mid-gestation releasing less Ca and P compared with growing pigs or sows in late-gestation. However, it is not known if values for STTD of Ca or retention of Ca and P that are measured in one period of gestation are representative of the entire gestation period.

Therefore, an experiment was conducted to test the hypothesis that the STTD of Ca from calcium carbonate and the response to microbial phytase on STTD of Ca and apparent total tract digestibility (ATTD) of P in corn-based diets fed to gestating sows are constant throughout the gestating period for sows. The second objective was to test the hypothesis that retention of Ca and P does not change during gestation.

 

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Enzymatic digestion turns food waste into feed for growing pigs

Jinno Cynthia, Yijie He, Dan Morash, Emily McNamara, Steve Zicari, Annie King, Hans H, Stein, Yanhong Liu. 2018. Enzymatic digestion turns food waste into feed for growing pigs. Anim. Feed Sci. Technol. 242:48-58. Link to full text

Comparative digestibility and retention rate of calcium and phosphorus in low- and high-phytate diets fed to gestating sows and growing pigs

Digestibility of Ca and P is most correctly determined as standardized total tract digestibility (STTD). Data for the STTD of P in most feed ingredients have been published, and the STTD of Ca has also been determined in many feed ingredients. However, in practical diet formulation, values for STTD of Ca and P obtained in growing pigs are also applied to sows although there is a lack of comparative data between growing pigs and sows.

Therefore, an experiment was conducted to test the hypothesis that no differences exist between gestating sows and growing pigs for basal endogenous losses, STTD, and retention of Ca and P.

 

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Digestibility of amino acids, fiber, energy, and concentrations of digestible and metabolizable energy in conventional and extruded yellow dent corn, wheat, and sorghum fed to growing pigs

Extrusion of cereal grains may be used to improve nutrient digestibility in cereal grains because addition of heat and pressure in combination with addition of moisture during the extrusion may gelatinize the starch, which results in an increase in starch digestibility. It is also possible that AA and energy digestibility are increased by the extrusion, but data to verify this hypothesis have not been published. Therefore, the objective of these experiments was to test the hypothesis that the ileal digestibility of AA and starch and the apparent total tract digestibility (ATTD) of ADF, NDF, and GE as well as the concentrations of DE and ME in corn, wheat, and sorghum are increased by extrusion.

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The level of feed intake does not influence digestibility of calcium and phosphorus in diets fed to gestating sows, but gestating sows have reduced digestibility of calcium and phosphorus compared with growing gilts

Lee, S. A., G. A. Casas, and H. H. Stein. 2018. The level of feed intake does not influence digestibility of calcium and phosphorus in diets fed to gestating sows, but gestating sows have reduced digestibility of calcium and phosphorus compared with growing gilts. Can. J. Anim. Sci. 98:591-594. Link to abstract

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Non-antibiotic feed additives in diets for pigs: A review

Liu, Y., C. D. Espinosa, J.  J. Abelilla, G. A. Casas, L. V. Lagos, S. A. Lee, W. B. Kwon, J. K. Mathai, D. M. D. L. Navarro, N. W. Jaworski, and H. H. Stein. 2018. Non-antibiotic feed additives in diets for pigs: A review. Anim. Nutr. 4:113-125. Link to full text (.pdf)

Methodology effects on determining the energy concentration and the apparent total tract digestibility of components in diets fed to growing pigs

Huang, C., P. Li, X. Ma, N. W. Jaworski, H. H. Stein, C. Lai, J. Zhao, and S. Zhang. 2018. Methodology effects on determining the energy concentration and the apparent total tract digestibility of components in diets fed to growing pigs. Asian-Austr. J. Anim. Sci. 31:1315-1324. Link to full text (.pdf)

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Additivity of values for phosphorus digestibility in corn, soybean meal, and canola meal in diets fed to growing pigs

She, Y., Q. Wang, H. H. Stein, L. Liu, D. Li, and S. Zhang. 2018. Additivity of values for phosphorus digestibility in corn, soybean meal, and canola meal in diets fed to growing pigs. Asian-Austr. J. Anim. Sci. 31:1301-1307. Link to full text (.pdf)

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Effects of increasing concentrations of an Escherichia coli phytase on the apparent ileal digestibility of amino acids and the apparent total tract digestibility of energy and nutrients in corn-soybean meal diets fed to growing pigs

She, Y., J. C. Sparks, and H. H. Stein. 2018. Effects of increasing concentrations of an Escherichia coli phytase on the apparent ileal digestibility of amino acids and the apparent total tract digestibility of energy and nutrients in corn-soybean meal diets fed to growing pigs. J. Anim. Sci. 96:2804–2816. Link to abstract

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Ileal digestibility of amino acids in selected feed ingredients fed to young growing pigs

Casas, G. A., N. W. Jaworski, J. K. Htoo, and H. H. Stein. 2018. Ileal digestibility of amino acids in selected feed ingredients fed to young growing pigs. J. Anim. Sci. 96:2361–2370. Link to abstract

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Effects of full fat rice bran and defatted rice bran on growth performance and carcass characteristics of growing-finishing pigs

Casas, G. A., M. F. Overholt, A. C. Dilger, D. D. Boler, and H. H. Stein. 2018. Effects of full fat rice bran and defatted rice bran on growth performance and carcass characteristics of growing-finishing pigs. J. Anim. Sci. 96:2293–2309. Link to abstract

Effects of physicochemical characteristics of feed ingredients on the apparent total tract digestibility of energy, DM, and nutrients by growing pigs

Navarro, D. M. D. L., E. M. A. M. Bruininx, L. de Jong, and H. H. Stein. 2018. Effects of physicochemical characteristics of feed ingredients on the apparent total tract digestibility of energy, DM, and nutrients by growing pigs. J. Anim. Sci. 96:2265–2277. Link to abstract

Effects of microbial phytase on standardized total tract digestibility of phosphorus in hybrid rye, barley, wheat, corn, and sorghum fed to growing pigs

Until recently, rye has been less suitable for livestock feed than other cereal grains due to the risk of ergot contamination. However, recently developed hybrids are less susceptible to ergot contamination. There is limited information about the nutritional value of hybrid rye when fed to pigs.

In cereal grains, most of the phosphorus is bound to phytic acid, and is not available to pigs unless phytase is present. This is usually achieved by adding supplemental phytase, derived from microbes, to the diets. However, rye contains more intrinsic phytase than other cereal grains, so the phosphorus in rye may be more digestible. The addition of microbial phytase might also have less of an effect on phosphorus digestibility in rye than in other grains because of the high concentrations of intrinsic phytase in rye, but limited information about digestibility of phosphorus in rye has been reported.

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High-protein distillers dried grains with solubles produced using a novel front-end– back-end fractionation technology has greater nutritional value than conventional distillers dried grains with solubles when fed to growing pigs

Espinosa, C. D. and H. H. Stein. 2018. High-protein distillers dried grains with solubles produced using a novel front-end– back-end fractionation technology has greater nutritional value than conventional distillers dried grains with solubles when fed to growing pigs. J. Anim. Sci. 96:1869-1876. Link to abstract

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The contribution of digestible and metabolizable energy from high-fiber dietary ingredients is not affected by inclusion rate in mixed diets fed to growing pigs

Navarro, D. M. D. L., E. M. A. M. Bruininx, L. de Jong,  and H. H. Stein. 2018. The contribution of digestible and metabolizable energy from high-fiber dietary ingredients is not affected by inclusion rate in mixed diets fed to growing pigs. J. Anim. Sci. 96:1860-1868. Link to abstract

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