@article{spears_lloyd_flores_krafka_hyda_grimes_2024, title={Chromium propionate in turkeys: effect on performance and animal safety}, volume={103}, ISSN={["1525-3171"]}, DOI={10.1016/j.psj.2023.103195}, abstractNote={Two hundred and eighty-eight male Nicholas Large White turkey poults were used to determine the effect of supplementing turkeys with chromium propionate (Cr Prop) from 1 to 84 d of age on performance and animal safety. Treatments consisted of Cr prop supplemented to provide 0, 0.2, or 1.0 mg Cr/kg diet. One mg of supplemental Cr is 5 times (x) the minimal concentration of Cr Prop that enhanced insulin sensitivity in turkeys. Each treatment consisted of 8 floor pens with 12 poults per pen. Turkeys were individually weighed initially, and at the end of the starter 1 (d 21), starter 2 (d 42), grower 1 (d 63), and grower 2 phase (d 84). On d 85, blood was collected from the wing vein in heparinized tubes from 2 turkeys per pen for plasma chemistry measurements. A separate blood sample was collected from the same turkeys in tubes containing K2EDTA for hematology measurements. Turkey performance was not affected by treatment during the starter 1 phase. Gain was greater (P = 0.024) and feed/gain lower (P = 0.030) for turkeys supplemented with Cr compared with controls during the starter 2 phase. Over the entire 84-d study turkeys supplemented with Cr had greater (P = 0.005) ADG and tended (P = 0.074) to gain more efficiently than controls. Gain (P = 0.180) and feed/gain (P = 0.511) of turkeys supplemented with 0.2 mg Cr/kg did not differ from those receiving 1.0 mg Cr/kg over the entire 84-d study. Feed intake was not affected by treatment. Body weights of turkeys supplemented with Cr were heavier (P = 0.005) than controls by d 84. Chromium supplementation did not affect hematological measurements and had minimal effect on plasma chemistry variables. Results of this study indicates that Cr Prop supplementation can improve turkey performance, and is safe when supplemented to turkey diets at 5x the minimal concentration that enhanced insulin sensitivity.}, number={1}, journal={POULTRY SCIENCE}, author={Spears, J. W. and Lloyd, K. E. and Flores, K. and Krafka, K. and Hyda, J. and Grimes, J. L.}, year={2024}, month={Jan} }
 @article{spears_lloyd_krafka_hyda_grimes_2024, title={Chromium propionate in turkeys: effects on insulin sensitivity}, volume={103}, ISSN={["1525-3171"]}, DOI={10.1016/j.psj.2023.103215}, abstractNote={The objective of this study was to evaluate the effects of dietary chromium (Cr), as Cr propionate (Cr Prop), on measures of insulin sensitivity in turkeys. Plasma glucose and non-esterified fatty acid (NEFA), and liver glycogen concentrations were used as indicators of insulin sensitivity. One-day-old Nicholas Large White female poults (n = 336) were randomly assigned to dietary treatments consisting of 0 (control), 0.2, 0.4, or 0.6 mg supplemental Cr/kg diet. Each treatment consisted of 12 replicate cages with 7 turkeys per cage. Final BW were taken on d 34, and on d 35 two birds from each cage were sampled for plasma glucose and NEFA, and liver glycogen determination at the initiation (fed state) and termination (fasted state) of a 24-h fast. Following a 24-h fast, two turkeys per cage were refed (refed state) their treatment diet for 4 h, and then harvested. Feed/gain and ADG did not differ between control and Cr-supplemented turkeys over the 34-d study, but feed intake tended (P = 0.071) to be greater for controls than turkeys receiving 0.4 mg Cr/kg diet. Fed turkeys had greater plasma glucose (P = 0.002) and liver glycogen (P = 0.001) concentrations, and lower (P = 0.001) NEFA concentrations than fasted birds. Turkeys refed after fasting had greater (P = 0.001) plasma glucose and liver glycogen concentrations, and lower (P = 0.001) plasma NEFA levels than fed turkeys. Liver glycogen and plasma NEFA concentrations did not differ among control and Cr-supplemented birds in the fed, fasted, or refed state. Plasma glucose concentrations were not affected by treatment in fed or fasted turkeys. Turkeys supplemented with 0.2 or 0.4 mg Cr/kg and refed after fasting had lower (quadratic, P = 0.038) plasma glucose concentrations than controls. Plasma glucose concentrations in refed birds did not differ among Cr-supplemented turkeys. The lower plasma glucose concentration in Cr-supplemented turkeys following refeeding is consistent with Cr enhancing insulin sensitivity.}, number={1}, journal={POULTRY SCIENCE}, author={Spears, J. W. and Lloyd, K. E. and Krafka, K. and Hyda, J. and Grimes, J. L.}, year={2024}, month={Jan} }
 @article{spears_lloyd_krafka_hyda_grimesy_2024, title={Research Note: Chromium propionate for turkeys: effect on tissue chromium concentrations and human food safety}, volume={103}, ISSN={["1525-3171"]}, DOI={10.1016/j.psj.2023.103196}, abstractNote={This study was conducted to determine the effect of supplementing turkey diets with chromium propionate (Cr Prop) on Cr concentrations in tissues consumed by humans. Nicholas White male d-old poults were used in this study. Treatments consisted of 0, 0.20, or 1.0 mg supplemental Cr/kg diet. Each treatment consisted of 8 replicate floor pens with 12 poults housed per pen. Diets were fed ad libitum for 84 d. At the end of the study, 2 turkeys per pen were euthanized and samples of liver, breast muscle, kidney, and skin with adhering fat were collected from a similar location in each bird for Cr analysis. Orthogonal contrasts were used to compare the 2 Cr supplemented treatments to the control (0 added Cr) and 0.20 mg Cr to 1.0 mg Cr/kg diet. When expressed on a DM or wet tissue basis, liver (P = 0.001) and muscle (P = 0.015) Cr concentrations were greater in turkeys supplemented with Cr compared with controls. Chromium concentrations in liver were also greater (P = 0.001) in turkeys supplemented with 1.0 mg Cr/kg than those receiving 0.20 mg Cr/kg. Concentrations of Cr in kidney and skin + fat were not affected by treatment. Considering the adequate intake of Cr established for humans, supplementation of Cr Prop at up to 1.0 mg Cr/kg diet would have minimal effect on total Cr intake by humans.}, number={1}, journal={POULTRY SCIENCE}, author={Spears, J. W. and Lloyd, K. E. and Krafka, K. and Hyda, J. and Grimesy, J. L.}, year={2024}, month={Jan} }
 @article{spears_loh_lloyd_heldt_engle_2024, title={Trace mineral source and chromium propionate supplementation affect performance and carcass characteristics in feedlot steers}, volume={102}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skae106}, abstractNote={Abstract Angus-crossbred steers (n = 400; 369.7 ± 7.6 kg) were used to determine the influence of trace mineral (TM) source and chromium propionate (Cr Prop) supplementation on performance, carcass characteristics, and ruminal and plasma variables in finishing steers. Steers were blocked by body weight (BW) and randomly assigned within block to treatments in a 2 × 2 factorial arrangement, with factors being: 1) TM source (STM or HTM) and 2) Cr supplementation (0 or 0.25 mg Cr/kg DM, −Cr or + Cr, respectively). Treatments consisted of the addition of: 1) sulfate TM (STM; 90, 40, and 18 mg/kg DM of Zn, Mn, and Cu, respectively), 2) STM and 0.25 mg Cr/kg DM from Cr Prop, 3) hydroxychloride TM (HTM; 90, 40, and 18 mg/kg DM of Zn, Mn, and Cu, respectively), and 4) HTM and 0.25 mg Cr/kg DM from Cr Prop. Each treatment consisted of 10 replicate pens with 10 steers per pen. Body weights were obtained on consecutive days at the initiation and termination of the 154-d study. Steers were fed a steam-flaked corn-based finishing diet. Ractopamine hydrochloride was fed for the last 31 d of the study. Ruminal fluid and blood samples were obtained from one steer per pen on days 28 and 84 for ruminal volatile fatty acids (VFA) and plasma TM and glucose analysis. Steers were slaughtered at the end of the study and individual carcass data were collected. No Cr × TM source interactions (P = 0.48) were detected. Steers supplemented with HTM had greater (P = 0.04) hot carcass weight (HCW), dressing percentage (DP), longissimus muscle (LM) area, and USDA yield grade (YG), and tended (P = 0.12) to have greater average daily gain (ADG) than those receiving STM. Average daily gain, gain:feed, dressing percentage, and longissimus muscle area were greater (P = 0.04) for + Cr steers compared to—Cr steers. Hot carcass weight tended (P = 0.06) to be greater for + Cr steers. Ruminal acetate concentrations at 28 d were lesser (P = 0.01) for HTM vs. STM steers, and greater (P = 0.04) for + Cr steers compared to—Cr steers. Plasma concentrations of Zn, Cu, and Mn were not affected by TM source or Cr supplementation. Steers supplemented with Cr had greater (P = 0.05) plasma glucose concentrations than—Cr steers at 28 but not at 84 d. Results of this study indicate replacing STM with HTM improved carcass characteristics in finishing steers, and Cr Prop supplementation improved steer performance and carcass characteristics.}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Spears, Jerry W. and Loh, Huey Yi and Lloyd, Karen E. and Heldt, Jeff S. and Engle, Terry E.}, year={2024}, month={Jan} }
 @article{spears_siciliano_pratt-phillips_lloyd_goertzen_krafka_hyda_rounds_2020, title={Chromium propionate improves insulin sensitivity in horses following oral concentrate consumption}, volume={98}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skaa278.160}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Spears, Jerry W. and Siciliano, Paul and Pratt-Phillips, Shannon and Lloyd, Karen and Goertzen, Ellen and Krafka, Kristi and Hyda, Jill and Rounds, Whitney}, year={2020}, month={Nov}, pages={88–88} }
 @article{spears_lloyd_siciliano_pratt-phillips_goertzen_mcleod_moore_krafka_hyda_rounds_2020, title={Chromium propionate increases insulin sensitivity in horses following oral and intravenous carbohydrate administration}, volume={98}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skaa095}, abstractNote={Abstract}, number={4}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Spears, Jerry W. and Lloyd, Karen E. and Siciliano, Paul and Pratt-Phillips, Shannon and Goertzen, Ellen W. and McLeod, Sarah J. and Moore, Jennifer and Krafka, Kristi and Hyda, Jill and Rounds, Whitney}, year={2020}, month={Apr} }