@article{warren_pitman_hodgson_thompson_livingston_2024, title={Dietary Super-Doses of Cholecalciferol Fed to Aged Laying Hens Illustrates Limitation of 24,25-Dihydroxycholecalciferol Conversion}, volume={8}, ISSN={["2475-2991"]}, DOI={10.1016/j.cdnut.2024.102156}, abstractNote={Older humans taking high concentrations of vitamin D}, number={5}, journal={CURRENT DEVELOPMENTS IN NUTRITION}, author={Warren, Matthew F. and Pitman, Pete M. and Hodgson, Dellila and Thompson, Nicholas C. and Livingston, Kimberly A.}, year={2024}, month={May} }
 @misc{warren_livingston_2021, title={Implications of Vitamin D Research in Chickens can Advance Human Nutrition and Perspectives for the Future}, volume={5}, ISSN={["2475-2991"]}, DOI={10.1093/cdn/nzab018}, abstractNote={Abstract The risk of vitamin D insufficiency in humans is a global problem that requires improving ways to increase vitamin D intake. Supplements are a primary means for increasing vitamin D intake, but without a clear consensus on what constitutes vitamin D sufficiency, there is toxicity risk with taking supplements. Chickens have been used in many vitamin-D-related research studies, especially studies involving vitamin D supplementation. Our state-of-the-art review evaluates vitamin D metabolism and how the different hydroxylated forms are synthesized. We provide an overview of how vitamin D is absorbed, transported, excreted, and what tissues in the body store vitamin D metabolites. We also discuss a number of studies involving vitamin D supplementation with broilers and laying hens. Vitamin D deficiency and toxicity are also described and how they can be caused. The vitamin D receptor (VDR) is important for vitamin D metabolism; however, there is much more to understand about VDR in chickens. Potential research aims involving vitamin D and chickens should explore VDR mechanisms that could lead to newer insights into VDR. Utilizing chickens in future research to help elucidate vitamin D mechanisms has great potential to advance human nutrition. Finding ways to increase vitamin D intake will be necessary because the coronavirus disease 2019 (COVID-19) pandemic is leading to increased risk of vitamin D deficiency in many populations. Chickens can provide a dual purpose with addressing pandemic-caused vitamin D deficiency: 1) vitamin D supplementation gives chickens added-value with the possibility of leading to vitamin-D-enriched meat and egg products; and 2) using chickens in research provides data for translational research. We believe expanding vitamin-D-related research in chickens to include more nutritional aims in vitamin D status has great implications for developing better strategies to improve human health.}, number={5}, journal={CURRENT DEVELOPMENTS IN NUTRITION}, author={Warren, Matthew F. and Livingston, Kimberly A.}, year={2021}, month={May} }
 @article{warren_vu_toomer_fernandez_livingston_2020, title={Efficacy of 1-alpha-Hydroxycholecalciferol Supplementation in Young Broiler Feed Suggests Reducing Calcium Levels at Grower Phase}, volume={7}, ISSN={["2297-1769"]}, DOI={10.3389/fvets.2020.00245}, abstractNote={Increasing biopotency of cholecalciferol (D3) from vitamin sources is essential in the poultry industry to meet nutritional demands and counter stressors. D3 exhibits hormonal traits and is responsible for calcium (Ca) absorption. 1-α-Hydroxycholecalciferol (1α) is a synthetic form of D3 that has equal efficacy and is cheaper to synthesize than 1,25-dihydroxycholecalciferol (active form of D3), on broilers. However, 1α bypasses a critical regulatory point, the kidney, and may consequently lead to toxicity levels of Ca via Ca absorption. This study examined 1α supplementation in broiler diets with different Ca inclusion levels to determine if 1α at higher Ca levels caused Ca toxicity at starter and grower phases with Ross 708 male broiler chicks. In Experiment 1 (1–15 days of age), chicks were assigned to one of 10 treatment starter diets with five levels of Ca inclusion (0.80, 0.95, 1.10, 1.25, and 1.40%) with or without 1α supplementation (5 μg 1α/kg in feed) and eight replicate cages per treatment. In Experiment 2, chicks were fed common starter diet until 16 days of age, and then they were assigned to one of eight treatment diets with four levels of Ca inclusion (0.54, 0.76, 0.98, or 1.20%) with or without 1α supplementation (5 μg 1α/kg in feed). At the end of both experiments, blood was collected from broilers to determine blood chemistry, including concentrations of vitamin D metabolites. Intestinal tissues were also collected to examine gene expression. In Experiment 1, broilers not fed 1α exhibited a quadratic effect in ionized blood Ca (iCa) as dietary Ca inclusion levels increased; 1α-fed broilers displayed an increase in iCa as Ca inclusion levels increased (p = 0.0002). For Experiment 2, 1α-fed broilers displayed a decrease in 25-hydroxycholecalciferol plasma concentration as dietary Ca inclusion levels increased (p = 0.035); also, increasing Ca inclusion in diets increased expression of duodenal sodium phosphate cotransporter type II b (NPTIIb, p = 0.03). Our findings imply that inclusion of 1α was beneficial because 1α enhanced Ca absorption during the starter phase; however, to avoid potential Ca toxicity or antagonism while using 1α during the grower phase, there should be consideration with reducing dietary Ca levels.}, journal={FRONTIERS IN VETERINARY SCIENCE}, author={Warren, Matthew F. and Vu, Thien C. and Toomer, Ondulla T. and Fernandez, Juan David and Livingston, Kimberly A.}, year={2020}, month={Jun} }
 @article{warren_hallowell_higgins_liles_hood_2019, title={Maternal Dietary Protein Intake Influences Milk and Offspring Gut Microbial Diversity in a Rat (Rattus norvegicus) Model}, volume={11}, ISSN={["2072-6643"]}, DOI={10.3390/nu11092257}, abstractNote={Historically, investigators have assumed microorganisms identified in mother’s milk to be contaminants, but recent data suggest that milk microbiota may contribute to beneficial maternal effects. Microorganisms that colonize the gastrointestinal tracts of newborn mammals are derived, at least in part, from the maternal microbial population. Milk-derived microbiota is an important source of this microbial inocula and we hypothesized that the maternal diet contributes to variation in this microbial community. To evaluate the relationship between a mother’s diet and milk microbiome, we fed female rats a low- or high-protein diet and mated all individuals. Milk and cecal contents were collected from dams at peak lactation (14-day post-partum), and the bacterial composition of each community was assessed by 16S rRNA gene amplicon sequencing. Our findings revealed higher dietary protein intake decreased fecal microbial diversity but increased milk microbial and pup cecum diversity. Further, the higher dietary protein intake resulted in a greater abundance of potentially health-promoting bacteria, such as Lactobacillus spp. These data suggest that dietary protein levels contribute to significant shifts in the composition of maternal milk microbiota and that the functional consequences of these changes in microbial inocula might be biologically important and should be further explored.}, number={9}, journal={NUTRIENTS}, author={Warren, Matthew F. and Hallowell, Haley A. and Higgins, Keah V. and Liles, Mark R. and Hood, Wendy R.}, year={2019}, month={Sep} }