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Title:Effects of conditionally essential fatty acid supplementation on neural and immune development in the young pig
Author(s):Hahn, Kaylee Elizabeth
Advisor(s):Dilger, Ryan N
Contributor(s):Donovan, Sharon M; Nakamura, Manabu T; Freund, Gregory G
Department / Program:Nutritional Sciences
Discipline:Nutritional Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Fatty Acid
Infant Formula
Abstract:Arachidonic acid (ARA; 20:4n-6) and docosahexaenoic acid (DHA; 22:6n-3) are long-chain polyunsaturated fatty acids (LCPUFA) naturally present in human breast milk (HM) and routinely supplemented in infant formula (IF). In IF-fed infants, the inclusion of preformed ARA and DHA is shown to yield more similar tissue FA accretion, cognitive and visual development, and immune response to that of a breastfed infant. Historically, these LCPUFA have been added together, and the physiological responses to independent ARA and DHA supplementation are poorly understood. Additionally, while ARA and DHA forms, including triglyceride (TG) and phospholipid, are known to influence bioavailability and tissue accretion, little is known about the use of these LCPUFA as free fatty acid (FFA) during early development. Using the young pig model, two experiments were conducted to help to fill these knowledge gaps. The first experiment explored the impact of independent and combined ARA and DHA supplementation. Intact male pigs received one of four dietary treatments (N = 12 per treatment) from postnatal day 2 to 30 with the following target ARA/DHA levels, as a percent of total FA: CON (0.00/0.00), ARA (0.80/0.00), DHA (0.00/0.80), and ARA+DHA (0.80/0.80). Tissue FA accretion, immune response, sleep and motor activity, and myelin thickness in the corpus callosum were evaluated. There were no differences in intake or growth between dietary groups, nor did supplementation differentially affect immune response or myelination outcomes. DHA supplementation alone increased brain DHA, but decreased ARA compared with other groups, while ARA alone increased brain ARA compared with all other groups but did not affect brain DHA compared with CON. The combined ARA+DHA increased brain DHA levels but did not affect brain ARA levels compared with the CON. Pigs fed ARA or ARA+DHA also exhibited higher levels of activity than those fed CON or DHA, and the inclusion of ARA and DHA alone induced differences in time spent asleep compared with CON and ARA+DHA. Together, these data support the case for ARA inclusion when DHA is supplemented in IF to support neurodevelopment and brain ARA accretion. The second study investigated the safety and efficacy of novel sodium and potassium salts of ARA derived from M. alpina oil (Na-ARA and K-ARA), both of which dissociate to Na+/K+ and FFA upon contact with water. Male and female pigs were randomized to one of four dietary treatments (N = 16 per treatment) from postnatal day 2 to 23. ARA and DHA were included as either TG or salt form at the following target ARA/DHA concentrations, as percent of total FA: TT (0.47 TG/0.32 TG), NaT (0.47 Na-salt/0.32 TG), KT (0.47 K-salt/0.32 TG), Na0 (0.47 Na-salt/0.00), and NaNa (0.47 Na-salt/0.32 Na-salt). Overall, the inclusion of ARA and DHA in salt form did not affect growth performance, liver histology, or substantially influence hematological outcomes compared with the TG forms. Bioequivalence assessments confirmed both Na-ARA and K-ARA were 100% bioequivalent to the TG-ARA based on ARA accretion in the cerebral cortex and retinal tissues. These findings demonstrate that the use of these novel FA salts in the young pig was both safe and nutritionally bioequivalent to TG-ARA for critical neural tissues. Overall, the results from these studies demonstrate the importance of balancing dietary ARA and DHA supplementation in IF to support structural and functional brain development, as well as confirm the safety of novel lipid forms of ARA and DHA for use in IF.
Issue Date:2020-10-16
Rights Information:Copyright 2020 Kaylee Hahn
Date Available in IDEALS:2021-03-05
Date Deposited:2020-12

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