Cristobal, Minoy, Jessica P. Acosta, Su A Lee, and Hans H. Stein. 2020. A new source of high-protein distillers dried grains with solubles (DDGS) has greater digestibility of amino acids and energy, but less digestibility of phosphorus, than de-oiled DDGS when fed to growing pigs. Journal of Animal Science, 2020, Vol. 98, No. 7, 1–9. doi:10.1093/jas/skaa200.

Lancheros, J. P., C. D. Espinosa, H. H. Stein. 2020. Effects of particle size reduction, pelleting, and extrusion on the nutritional value of ingredients and diets fed to pigs: A review. Animal Feed Science and Technology 268 (2020) 114603. https://doi.org/10.1016/j.anifeedsci.2020.114603.

In many parts of the world, including the United States, corn is the primary energy source used in diets for pigs, but there are no published data comparing the growth performance of growing pigs fed diets in which hybrid rye replaces corn. Unfamiliarity with hybrid rye also makes some producers in the United States reluctant to try feeding hybrid rye to pigs, as there is a long-standing belief that rye is less palatable than other feed ingredients. Therefore, two experiments were conducted to test the hypotheses that there is no difference in feed preference for diets containing either hybrid rye or corn as the exclusive cereal grain source, and that hybrid rye may replace a portion of corn in diets for growing pigs without adversely affecting growth. 

Rundle, Carly M., Valeria Artuso-Ponte, and Hans H. Stein. 2020. Effects of isoquinoline alkaloids on apparent ileal digestibility of amino acids, acid hydrolyzed ether extract, and starch by young growing pigs fed corn-soybean meal diets. Transl. Anim. Sci. 2020.4:1-7. doi: 10.1093/tas/txaa054. Link to full text. 

Acosta, Jesus A., Hans H. Stein, and John F. Patience. 2020. Impact of increasing the levels of insoluble fiber and on the method of diet formulation measures of energy and nutrient digestibility in growing pigs. Journal of Animal Science, 2020, 1–9. doi:10.1093/jas/skaa130. Link to full text.

Calcium requirements by pigs are expressed as total Ca because of a lack of data for the digestibility of Ca in feed ingredients, but it is believed that a ratio between standardized total tract digestible (STTD) Ca and STTD P is a more appropriate way to express requirements for Ca by pigs. Values for Ca digestibility in different Ca-containing feed ingredients were recently generated using diets without or with microbial phytase, which allowed for the formulation of diets based on STTD Ca values. A number of experiments were also conducted to determine STTD Ca to STTD P requirements to optimize growth performance and bone mineralization of pigs from 11 to 25 kg, 25 to 50 kg, 50 to 85 kg, and 100 to 130 kg. However, these experiments were performed independently and in experiments lasting only 3 to 5 weeks. Therefore, a follow-up experiment was conducted to test the hypothesis that the requirement for Ca expressed as a ratio between STTD Ca and STTD P obtained in short-term experiments may be applied to pigs fed diets without or with microbial phytase from 11 to 130 kg.

McGhee, M. L., and H. H. Stein. 2020. Hybrid rye instead of corn does not impede pig growth. National Hog Farmer, Online edition, April 30, 2020. Link to full text. 

Kim, Beob G., Su A Lee, Kyu R. Park, and Hans H. Stein. 2020. At least 3 days of adaptation are required before indigestible markers (chromium, titanium, and acid insoluble ash) are stabilized in the ileal digesta of 60-kg pigs, but values for amino acid digestibility are affected by the marker. Journal of Animal Science, 2020,  Vol. 98: No.

Leucine is a key regulator that stimulates catabolism of branched-chain AA (BCAA; i.e., Leu, Ile, and Val) in skeletal muscle and liver. If diets fed to pigs contain excess Leu, catabolism of all 3 BCAA may increase because of the stimulating effect of the Leu metabolite, α-keto isocaproate, on the branched-chain α-keto acid dehydrogenase enzyme complex, which is responsible for degradation of the 3 branched-chain α-keto acids that originate from metabolism of the 3 BCAA. Serum Ile and Val concentrations were reduced by excess dietary Leu in growing pigs, and high dietary Leu reduces feed intake and growth performance in pigs, which may be a result of the imbalanced supply of BCAA that result from increased metabolism of Val and Ile. Recent data confirmed that excess dietary Leu reduced growth performance and tended to reduce protein synthesis, which is likely a result of reduced availability of Val and Ile.