Feline lipid metabolism is a topic for greater exploration due to this specie?s
unique characteristics. Cats express limited Delta 6-desaturase activity necessary for
conversion of linoleic acid (LA, 18:2n-6) to arachidonic acid (AA, 20:4n-6). The
possibility exists that Gamma-linolenic acid (GLA, 18:3n-6) may serve as a precursor of AA in
reproductive tissues especially if coupled with chain elongation and a functionally active
Delta 5-desaturase. In addition no research has been conducted regarding feline reproductive
Delta 8-desaturase activity as an alternate to the production of AA.
To investigate desaturation activities, a group of 26 adult female cats were
randomly assigned into 1 of 3 groups based on the diet fed: High Linoleic Acid (HL,
n=7), Low Linoleic Acid (LL, n=9), and High Gamma-Linolenic Acid (GLA, n=10).The diets
were fed for 300 days prior to ovariohysterectomy at which time EDTA plasma and
ovarian, uterine, and subcutaneous adipose tissues were collected. Homogenates of each
tissue were prepared and frozen in aliquots at -80 degrees C. Total lipids were extracted from the
plasma and tissue homogenates followed by phospholipid (PL) fractionation via thin layer
chromatography and fatty acid (FA) analyses by gas chromatography. The Shapiro-Wilks test was used to determine normal distribution of FA data followed by One-Way ANOVA
and Tukey multiple comparisons (p<0.05). Plasma PLs were significantly increased in
both GLA and dihomo-Gamma-linolenic acid (DGLA, 20:3n-6Delta8,11,14) in the GLA group and
statistically increased in 20:2n-6 and 20:3n-6(Delta5,11,14) in the HL group. Uterine tissue
homogenates had significantly increased amounts of DGLA and AA, however ovarian
tissue showed an increase of only DGLA. Adipose tissue FAs showed significantly high
amounts of DGLA in the GLA group.
It is concluded that a high GLA diet results in increased AA in uterine, but not
ovarian, tissues and thus may supply eicosanoid precursors in support of reproduction.
The presence of increased amounts of 20:3n-6(Delta5,11,14) and not AA in the plasma and
uterine tissues in the HL group suggests that Delta6-desaturase cannot be induced and that
Delta8-desaturase is not active when feeding high dietary LA. Furthermore, the increase in
DGLA may provide an adipose storage reservoir for additional conversion under times of
metabolic need. These data support the presence of a functionally active Delta5-desaturase in
uterine, but not ovarian, tissues. The findings also suggest that increased dietary GLA
may be used to meet the AA requirements for reproduction in cats in the absence of an
animal based pre-formed source of AA.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2009-12-7267 |
| Date | 2009 December 1900 |
| Creators | Chamberlin, Amy Jo |
| Contributors | Bauer, John E. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | application/pdf |
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