Investigating the effects of long chain polyunsaturated fatty acids on lipid metabolism and body composition in the neonatal pig

by Mathews Oliver, Susan Ashley

Abstract (Summary)
MATHEWS OLIVER, SUSAN ASHLEY. Investigating the potential effects that long chain polyunsaturated fatty acids have on lipid metabolism in the piglet as a model for the human infant. (Under the direction of Dr. Robert J. Harrell and Dr. Jack Odle.)

The essential fatty acids (EFA) linoleic acid (LA) and linolenic acid (LN) are necessary for growth and development. Tissues of the central nervous system and the retina depend on the conversion of LA to arachidonic acid (AA) and LN to docosahexaenoic acid (DHA). Research in human infants has indicated that supplementation of infant formulas with AA and DHA promotes visual and neural development. The objective of the first study was to determine the utilization as well as the safety and efficacy of two sources of LCPUFA. Piglets (n=10/group) had ad libitum access from day 1 to 16 of age to a skim milk-based formula with different fat sources added to provide 50% of the energy. Treatments included: control with no added LCPUFA (CNTL), single cell oil triglyceride (TG), TG with phospholipid and cholesterol added to match phospholipid content in the PL diet (TG+PL), egg phospholipid (PL), and an essential fatty acid deficient group (EFAD). Formulas with LCPUFA provided 0.6% of fatty acids as AA and 0.3% as DHA. Total plasma AA and DHA concentrations (expressed as weight % of total lipid fatty acids) were greater in the TG compared to the CNTL (P<0.05), but there were no differences among the TG, TG+PL or PL (P>0.2). Apparent dry matter digestibility was 10% greater in the CNTL, TG, and TG+PL compared to the PL (P<0.002). Total body accretion of essential fatty acids (EFA) were lower in EFAD compared to all other groups (P<0.01). Accretion of AA and DHA was greatest in the TG compared to CNTL (P<0.02), but surprisingly, EFAD had similar accretion of AA as TG. CNTL had 40% longer ileal villi than the PL (P<0.03), but the TG and TG+PL were similar to CNTL. These data demonstrate that the TG source of AA and DHA may be a more efficacious supplement for infant formulas.

Over the last decade, the prevalence of childhood obesity has increased significantly in the US. Conjugated linoleic acid (CLA) has been shown to reduce body fat in many species, but little is known about the metabolic interactions between CLA and EFA. Two replicates of 12, 1 d old pigs were fed a milk-based formula ad libitum for 17 d that contained 25%(HF) or 3% (LF) fat with either 1% CLA (+CLA) or 1% sunflower oil (-CLA). LF fed pigs consumed 10% more dry formula than HF fed pigs (P<0.05), but 19% less metabolizable energy (P<0.01). In vitro ?-oxidation of 14C-arachidonate, linoleate, and palmitate was not affected by CLA (P>0.2) or level of dietary fat (P>0.1) in liver, brain, or muscle tissue. Accumulation of body lipid and protein was reduced by 34% and 14%, respectively in pigs fed supplemental CLA (P<0.05). CLA was only detected in pigs fed CLA, with more accumulation found in the LF fed pigs than the HF fed pigs (P<0.01). Total body accretion of LA, AA and DHA were reduced by fat level (P<0.0001) and both LA and LN were reduced by CLA (P<0.0003). These data suggest that CLA in conjunction with a low fat diet reduced body fat while not affecting in vitro oxidation of essential fatty acids.

Bibliographical Information:

Advisor:Dr. Sarah L. Ash; Dr. Jack Odle; Dr. Robert Harrell; Dr. Carolyn Dunn

School:North Carolina State University

School Location:USA - North Carolina

Source Type:Master's Thesis



Date of Publication:02/14/2003

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