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The role of dietary omega-3 and omega-6 essential fatty acids in the nutrition of dogs and cats: A review


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Omega-3 and omega-6 fatty acids are essential in all mammalians for normal growth and prevention of several diseases. Because of the seed oil production tendencies and the feeding techniques of farm animals, in the Western countries, diets for humans as well as homemade diets for dogs and cats are usually very high in omega-6 and low in omega-3 fatty acids. Several studies have shown that an optimal omega-6/omega-3 fatty acid ratio (about 6 to 1) in the diet of dogs and cats may reduce the incidence of some diseases, such as cancer and sudden cardiac death. Furthermore, the use of fatty acid supplements has proved to be beneficial in the treatment of several pathogenic conditions, such as chronic inflammatory diseases, atopy, chronic renal insufficiency, and some types of cancer. Therefore, particular attention should be paid to the type and quantity of fat sources that are used when diets for dogs and cats are formulated, in order to assure the optimal amount and balance of omega-3 and omega-6 fatty acids in the food.
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The role of dietary omega-3 and
omega-6 essential fatty acids in the
nutrition of dogs and cats: a review
1 DIMORFIPA, Università di
Bologna, Ozzano Emilia, Italy
2 Scottish Agricultural College,
Edinburgh, United Kingdom
Indirizzo per la corrispondenza:
Dr. Giacomo Biagi
via Tolara di Sopra 50
40064 – Ozzano Emilia (BO), Italy
Tel: +39-051-2097363
Fax: +39-051-2097373
Il ruolo degli acidi
grassi essenziali
omega-3 e omega-6
nell’alimentazione del
cane e del gatto:
una rassegna
Dog, cat, essential fatty acids,
omega-3, omega-6
Cane, gatto, acidi grassi essenziali,
omega-3, omega-6
Omega-3 and omega-6 fatty acids are essential in all mammalians for nor-
mal growth and prevention of several diseases. Because of the seed oil pro-
duction tendencies and the feeding techniques of farm animals, in the
Western countries, diets for humans as well as homemade diets for dogs
and cats are usually very high in omega-6 and low in omega-3 fatty acids.
Several studies have shown that an optimal omega-6/omega-3 fatty acid
ratio (about 6 to 1) in the diet of dogs and cats may reduce the incidence
of some diseases, such as cancer and sudden cardiac death. Furthermore,
the use of fatty acid supplements has proved to be beneficial in the treat-
ment of several pathogenic conditions, such as chronic inflammatory dis-
eases, atopy, chronic renal insufficiency, and some types of cancer. There-
fore, particular attention should be paid to the type and quantity of fat
sources that are used when diets for dogs and cats are formulated, in order
to assure the optimal amount and balance of omega-3 and omega-6 fatty
acids in the food.
L’apporto alimentare di acidi grassi della serie omega-3 e omega-6 è essen-
ziale nei mammiferi al fine di assicurarne il corretto accrescimento e ridur-
re l’incidenza di alcune patologie. A causa delle odierne tendenze produtti-
ve nel settore delle piante oleaginose e delle moderne tecniche di alimenta-
zione degli animali da reddito, nei paesi occidentali, le diete dell’uomo, così
come quelle preparate in casa per cani e gatti, sono generalmente ricche di
acidi grassi omega-6 e povere di omega-3. Numerose ricerche hanno di-
mostrato che un rapporto ottimale tra acidi grassi omega-6 e omega-3 (in-
torno a 6 a 1) nella dieta di cani e gatti può ridurre l’incidenza di alcune
patologie, quali alcuni tumori e la morte cardiaca improvvisa. Inoltre, l’im-
piego di supplementi alimentari contenenti acidi grassi essenziali può risul-
tare di aiuto nel trattamento di diverse condizioni patologiche, quali malat-
tie infiammatorie a decorso cronico, atopia, insufficienza renale cronica ed
alcuni tipi di tumore. È pertanto molto importante tenere conto del tipo e
della quantità delle fonti lipidiche che si impiegano nella formulazione del-
le diete di cani e gatti, al fine di assicurare la giusta quantità ed il corretto
rapporto di acidi grassi essenziali nell’alimento.
Over the past 30 years, many stud-
ies have been conducted to investi-
gate the metabolism of polyunsatu-
rated fatty acids (PUFA) in hu-
mans and animals. Today, it is well
known that both omega-3 and
omega-6 fatty acids are essential in
mammalians for normal growth
and prevention of several diseases,
such as cardiovascular diseases, dia-
betes, hypertension, chronic in-
flammatory and autoimmune dis-
orders, and cancer.
The recommendations to increase
omega-6 fatty acids uptake to re-
duce plasma concentration of cho-
lesterol in humans have strongly
influenced seed oil production and
feeding techniques of farm animals.
The large use of grains and oils rich
in omega-6 fatty acids as feedstuffs
for farm animals has led to the pro-
duction of meat and eggs rich in
omega-6 and poor in omega-3 fatty
acids. Furthermore, modern aqua-
culture produces fish containing
less omega-3 fatty acids than wild
fish (1). As a consequence, diets for
humans as well as homemade diets
for dogs and cats are very likely to
be high in omega-6 and low in
omega-3 fatty acids.
The metabolism of omega-3 and
omega-6 essential fatty acids
The omega-3 and omega-6 fami-
lies consist of several fatty acids de-
rived from two precursors, linoleic
acid (LA, C18:2 n-6) and α-
linolenic acid (LNA, C18:3 n-3).
These two fatty acids can not be
synthesized by animals and must be
obtained from the diet. Once in-
gested, LA and LNA undergo the
action of two enzymic systems,
known as desaturase and elongase,
and are metabolised in other acids
of the same series. The desaturases
act by replacing a saturated bond
with a double one, the elongases
exert their action adding carbon
atoms to the acid in order to extend
the chain. The metabolic pathway
of the omega-3 and omega-6 fatty
acids is shown in figure 1.
Omega-3 and omega-6 fatty acids
compete for the same desaturase
enzymes (2). As a result, the pro-
portions of omega-6 and omega-3
Figure 1 - Metabolic pathway of the omega-3 and omega-6 fatty acids
AA = arachidonic acid; EPA = eicosapentaenoic acid; DHA = docosa-
hexaenoic acid
fatty acids that are available to
these enzymes directly affect the
quantity and proportions of arachi-
donic acid (AA, C20:4 n-6), eicos-
apentaenoic (EPA, C20:5 n-3) and
docosahexaenoic acid (DHA,
C22:6 n-3) that are formed.
Like other obligate carnivores, cats
show only little d-6 desaturase ac-
tivity and require foods of animal
origin as a source of AA, EPA and
DHA (3). Conversely, dogs are able
to convert LA and LNA to the
long-chain PUFA by desaturase
and elongase systems (4, 5).
The biological role of omega-3 and
omega-6 fatty acids
Long chain PUFA can have both a
functional and a structural role.
Arachidonic acid is found in fairly
high proportions in the membranes
of most cells, where it is bound as a
component of phospholipids. Upon
cellular stimulation AA is released
and becomes the substrate for the
synthesis of eicosanoids. Eicosa-
noids are polyunsaturated metabo-
lites of fatty acids which include
prostaglandins, thromboxanes,
leukotrienes, and hydroxylated
eicosatetraenoic acids (lipoxins).
DHA is an essential component of
cell membranes. DHA is particu-
larly present in the phospholipids
of retina, cerebral synaptosomes,
and sodium intra-membranous
channels (6). DHA seems to play a
very important role in:
1) brain development and growth
2) reproductive apparatus develop-
ment and growth
3) retinal tissue development and
EPA is mainly a precursor of
eicosanoids. When the diet is rich
in omega-6 and poor in omega-3
fatty acids, eicosanoids are mainly
produced from AA, but when ani-
mals ingest enough omega-3 fatty
acids, EPA and DHA partially re-
place the omega-6 fatty acids (es-
pecially AA) in cell membranes.
When the cell is injured, EPA and
AA are released from the mem-
brane by a phospholipase and
metabolised to eicosanoids by two
main enzymatic systems, ciclooxi-
genase and lipoxygenase. The
metabolic pathways for the produc-
tion of eicosanoids from AA and
EPA are shown in figure 2.
Eicosanoids that are derived from
AA are pro-inflammatory and pro-
aggregatory, and act as potent me-
diators of inflammation in type I
hypersensitivity reactions. Eicosa-
noids from EPA are less inflamma-
tory, vasodilatory, anti-aggregatory,
and prevent cardiac arrhythmia (6).
These actions resist those produced
by the eicosanoids from AA. The
main actions of EPA and AA are
summarized in table 1.
Dihomo-γ-linolenic acid (DGLA,
C20:3 n-6) is produced through
elongation from γ-linolenic acid
(GLA, C18:3 n-6). The eicosa-
noids (group 1 prostaglandins and
group 3 leukotrienes) that derive
from DGLA suppress the synthesis
of tumor necrosis factor-a which is
a strong proinflammatory cytokine.
Dietary sources of PUFA
Omega-6 fatty acids are widely dis-
tributed in food of vegetable and
animal origin. Most oils consumed
in the Western countries (particu-
larly corn, peanut, and sunflower
oil) are very rich in LA and contain
only little LNA. Among vegetable
oils, flaxseed oil is the one showing
the highest content in LNA; signif-
icant amounts of LNA are present
also in rapeseed and soybean oil,
and in walnuts. A major source of
EPA and DHA is oily fish, such as
sardine, salmon, mackerel, and
fresh tuna. The fatty acid composi-
tion of some foodstuffs is reported
in table 2.
Deficiency of PUFA in dogs and
Deficiencies of PUFA are not very
common in dogs and cats. Com-
mercial diets usually contain ade-
quate PUFA; nevertheless, products
that contain significant amounts of
PUFA must be protected from oxi-
dation with the inclusion of natural
or synthetic antioxidants and
avoiding all the factors that may
activate lipids oxidation during
production and storage, such as
light, high temperature, and hu-
midity. Deficiencies of PUFA may
occur when animals are fed for a
prolonged time inadequate home-
made diets or diets that have un-
dergone oxidation of lipids.
A PUFA deficiency in dogs is char-
acterized by dull dry hair, hair loss,
and skin lesions (7). Hansen and
Wiese (8) reported cases of external
otitis in PUFA-deficient dogs.
Because of their inability to convert
LA into AA (as well as LNA into
EPA and DHA), cats are more
likely to develop a PUFA deficien-
cy.When cats are fed a diet lacking
LA, they show signs of deficiency,
such as poor growth, skin lesions,
increased loss of water through the
skin, reduced platelet aggregation,
reproductive failure, and fatty liver.
These signs of deficiency may be
prevented by including LA into the
diet. Nevertheless, cats fed diets
containing adequate LA but lack-
ing AA showed reproductive failure
and impaired platelet aggregation
(9-11). Interestingly, male cats fed
LA-adequate AA-deficient diets
show normal reproduction func-
tions. This finding suggests that
some conversion of LA into AA
may take place (11). The existence
of some δ-6 desaturase activity in
cats was later confirmed by
Pawlosky et al. (12).
In rats, δ-6 desaturase activity in
the liver decreases at a rate propor-
Figure 2 - Metabolic pathways for the production of eicosanoids from AA and EPA
AA = arachidonic acid; EPA = eicosapentaenoic acid; DGLA = Dihomo-g-linolenic acid
tional to the animal age (13). Even
if there are no specific studies in
the dog, it seems reasonable that
also in old dogs the liver δ-6 desat-
urase activity may be lower and, as
a consequence, the conversion of
LA and LNA to their derivatives
may be decreased. Therefore,
adding a source of AA, EPA and
DHA to the diet of old dogs may
be helpful in preventing a deficien-
cy of these PUFA.
Excessive intake of PUFA in dogs
and cats
Cases of vitamin E deficiency in
cats receiving diets very high in
PUFA have been reported. Diets
with a very high fish content may
cause steatitis (“yellow fat disease”)
in cats if they are deficient in vita-
min E (14, 15). Momoi et al. (16)
observed that healthy cats receiving
a raw fish diet had a significant in-
crease of plasma lipid peroxide lev-
el. When a cat diet is very rich in
PUFA, the NRC (17) suggests a 3-
4 fold increase of vitamin E inclu-
sion in the food. Feeding dogs with
a diet with a very low omega-
6/omega-3 fatty acid ratio (1.6:1)
reduced plasma concentration of α-
tocopherol and increased lipid per-
oxidation (18).
The role of PUFA in the
development of the nervous system
of dogs and cats
The mammalian brain is very rich
in PUFA, especially DHA and AA
(19). In the retina, the rod outer
segment membranes of the pho-
toreceptors are very rich in DHA
(20). Essential fatty acid deficiency
during early brain development
may produce permanent and dele-
terious effects (21). Therefore, ade-
quate PUFA dietary levels in the
mother are very important both
during foetal and early postnatal
period. Ward et al (20) observed
that dietary supplementation with
different levels of DHA and/or AA
in neonatal rats increased deposi-
tion of PUFA in the brain but also
affected tissue levels of the other
In dogs, the retinal tissue is able to
synthesize DHA from docosapen-
taenoic acid (DPA, C22:5 n-3)
which can be obtained from LNA
(4). However, because the quantity
of LNA that is needed to optimise
neural tissue development is not
known, feeding bitches and puppies
with a source of dietary DHA is
the best approach to provide the
puppies with this nutrient.
In cats, brain DHA levels increase
during the last weeks of pregnancy
Arachidonic acid Effect EPA Effect
PGE2Platelet aggregation PGI3Platelet aggregation,
LTB4Inflammation LT B 5Inflammation
TXA2Platelet aggregation, TXA3Platelet aggregation
vasoconstriction vasoconstriction
TNF-α↑Inflammation IL-2b
IL-1β↑Inflammation Nitric Oxide Vasodilation
PAF Platelet aggregation
PAF = Platelet activating factor
Table 1 - Main actions of arachidonic and eicosapentaenoic acid (EPA)
and keep increasing during early
life. Sources of DHA and AA must
be present in the diet of the queen
to assure the correct development
of brain and retina of the kittens
The influence of PUFA on the
immune system of dogs and cats
As previously mentioned, dietary
lipids may modulate the immune
system influencing eicosanoids pro-
duction. Kearns et al. (23) showed
that, despite the antiinflammatory
properties of omega-3 PUFA, re-
ducing the omega-6/omega-3 fatty
acid ratio in the diet of dogs to 5:1
did not negatively affect the im-
mune function of old animals and
had some positive effect on the im-
mune system of young animals.
Feeding dogs with a diet rich in fish
oil reduced the production of
leukotriene B4,a strong proinflam-
matory eicosanoid derived from
AA, by neutrophiles (24, 25). In
another study (26), when dogs were
fed a diet with an omega-6/omega-
3 fatty acid ratio of 1.4:1, CD4+ T
lymphocyte count after vaccination
was lower than in control animals,
showing that a very low omega-
6/omega-3 fatty acid ratio reduced
immune response to vaccination. A
diet with an omega-6/omega-3 fat-
ty acid ratio of 1.4:1 reduced cell-
mediated immune response and
PGE2production in aged dogs (18).
Foodstuff Total Saturated Monouns. Polyunsaturated FA
FatFAFAC18:2 C18:3 C20:4 C20:5 C22:6 TOT
Beef, rib 6.1 2.03 1.99 0.57 0.11 0.16 0.14 0.07 1.21
Chicken, breast 0.9 0.29 0.23 0.11 0 0.07 0 0.02 0.25
Lamb, leg 2.5 1.01 0.86 0.24 0.01 0.09 0 0 0.35
Pork, loin 7.0 2.23 2.38 1.68 0 0.03 0 0 1.82
Mackerel 11.1 2.61 4.13 0.16 0.15 0.16 0.73 1.26 2.46
Salmon, fresh 12.0 2.97 4.60 0.15 0.09 0.05 0.89 1.19 3.05
Sardine 15.4 4.71 2.89 0.18 0.69 1.05 1.73 2.35 6.29
Tuna, fresh 8.1 3.35 1.51 0.15 0.09 tr. 0.80 2.15 3.20
Egg, whole 8.7 3.17 2.58 1.06 0.04 0.16 0 0 1.26
Butter 83.4 48.78 23.72 1.57 1.18 0002.75
Margarine 84.0 26.43 36.78 16.62 1.02 0 0 0 17.64
Corn oil 99.9 14.96 30.66 49.83 0.60 0 0 0 50.43
Flaxseed oil 99.9 9.40 20.20 12.70 53.30 0 0 0 66.00
Olive oil 99.9 16.16 74.45 7.85 0.99 0008.84
Peanut oil 99.9 19.39 52.52 27.87 000027.87
Rapeseed oil 99.9 6.31 61.52 20.54 9.08 0 0 0 29.62
Soybean oil 99.9 14.02 22.76 51.36 7.60 0 0 0 58.96
Sunflower oil 99.9 11.24 33.37 49.89 0.33 0 0 0 50.22
Walnuts 68.1 5.57 9.54 34.02 6.64 0 0 0 40.66
*Data from Marletta L, Carnovale E: Composizione degli alimenti. Aggiornamento 2000. Istituto Nazionale di Ricer-
ca per gli Alimenti e la Nutrizione. 2000. CDROM.
FA = fatty acids
Table 2 - Fatty acid composition of some foodstuffs (g per 100 g of edible portion)*
Because of the antiinflammatory
properties of the omega-3 PUFA,
many studies have been conducted
in animals and humans to investi-
gate the influence of dietary PUFA
on chronic diseases, such as arthro-
sis, dermatitis, and autoimmune
In human patients with rheuma-
toid arthritis, clinical improvement
is achieved with the consumption
of fish oil (27). Simopoulos (28)
has reviewed the beneficial effects
of omega-3 PUFA in human pa-
tients with inflammatory and au-
toimmune diseases.
In dogs with experimental and in-
fectious arthritis, leukotriene B4is
increased in synovial fluid (29, 30),
as it is in human patients with
rheumatoid arthritis (31). The re-
duction of the omega-6/omega-3
acid ratio in the diet of dogs with
osteoarthrosis of the elbow joint did
not reduce lameness during a 12
week study (32). At the present
time, considering the lack of litera-
ture, it is not possible to assess the
effects of dietary omega-3 PUFA on
chronic arthritis of dogs and cats.
In dogs, omega-3 PUFA have been
successfully used to treat a claw
disorder called symmetrical lupoid
onychodystrophy, usually charac-
terised by pain and lameness (33,
The role of PUFA in the treatment
of allergic dermatitis in dogs and
cats will be discussed in the next
The role of PUFA in the treatment
of atopy in dogs and cats
Many studies have investigated the
efficacy of PUFA in the manage-
ment of canine and feline atopy (al-
lergic inhalant dermatitis). It has
been estimated that 10-15% of the
canine population is affected by
atopy (35). Other types of allergies
that may be responsible for an al-
lergic dermatitis are flea bites and
food ingredients. The main clinical
sign of allergic dermatitis is pruri-
tus with secondary skin lesions
mainly resulting from self-trauma.
Depending on the presence of the
responsible allergens, pruritus may
or may not be seasonal. Otitis ex-
terna is noted in about 55% of the
dogs with atopic dermatitis (36).
Scott et al. (37) observed that a
commercial diet with an omega-
6/omega-3 fatty acid ratio of 5.5:1
reduced pruritus in almost 50% of
the atopic dogs used for the trial.
The favourable response was ob-
served after 7 to 21 days on the di-
et, and was lost 3 to 14 days after
the diet was withdrawn. During
another study with atopic dogs,
Harvey (38) observed that skin
condition was improved in animals
receiving a combination of fish oil
(rich in EPA and DHA) and bor-
age seed oil (rich in GLA) com-
pared to the control animals receiv-
ing olive oil as a placebo. During
another study, skin condition im-
provement was observed in 19 of
26 atopic dogs receiving a mixture
of fish oil and evening primrose oil
(also rich in GLA; 39). Another
source of GLA is blackcurrant seed
oil. When fed to atopic dogs,
blackcurrant seed oil reduced pruri-
tus, erythema and skin lesions (40).
Conversely, other researchers did
not notice any significant benefits
from feeding fish oil and evening
primrose oil to atopic dogs (41,
42). In another trial (43), changing
the dose of omega-3 PUFA and
the omega-6/omega-3 ratio did not
produce any benefit on clinical
signs in dogs with pruritus.
In cats with crusting dermatosis,
Harvey (44) observed that a mix-
ture of evening primrose oil and
fish oil was more effective than fish
oil alone in improving skin condi-
tion. During a precedent study
(45), six of eight cats with pruritus
showed some benefit from dietary
supplementation with PUFA.
Feeding an omega-3 fatty acid sup-
plement to non-pruritic cats with
miliary dermatitis lead to the com-
plete disappearance of clinical signs
in three animals of five (46). Con-
versely, in another study, feeding
primrose oil to 15 pruritic cats did
not improve their skin condition
(47). When used together with an
antihistamine, an omega-3/omega-
6 fatty acid supplement was effec-
tive in reducing pruritus in 6 cats of
11 (48). Interestingly, no benefit
was observed when the antihista-
mine or the fatty acid supplement
were used alone, suggesting a syn-
ergistic action of the two antiin-
flammatory agents tested.
The lack of clear benefits from
feeding PUFA to dogs and cats
with dermatitis and the sometimes
controversial results obtained may
be due to different causes, such as
inadequate duration of treatment,
lack of a control diet, different
composition of diets and supple-
ments used in the experiments, dif-
ferent doses of PUFA fed to the
animals, and different etiology of
Cardiovascular effects of PUFA in
The beneficial effects of omega-3
fatty acids on coronary heart dis-
ease have been shown in hundreds
of experiments in animals and hu-
mans (49). Dietary omega-3 fatty
acids prevent heart disease through
several actions, such as prevention
of arrhythmias, production of
prostaglandins and leukotrienes
with antiinflammatory properties
and inhibition of the synthesis of
cytokines and mitogens that aug-
ment inflammation, stimulation of
nitric oxide release, antithrombotic
properties, reduction of plasmatic
triacylglycerols and VLDL, and in-
hibition of atherosclerosis (50).
Despite the fact that atherosclerosis
is not a major clinical problem in
dogs and cats, it is known that sled
dogs like trained human athletes
may develop pathological alter-
ations of the heart conduction sys-
tem (fibrosis and fat infiltration)
that can eventually lead to sudden
death (51). Billman et al. (52, 53)
showed that omega-3 PUFA have
antiarrhythmic effects also in dogs
and can prevent sudden cardiac
death. Kang and Leaf (54) ob-
served that omega-3 PUFA stabi-
lize electrically every myocyte in
the heart of dogs by increasing by
approximately 50% the electrical
stimulus required to elicit an action
potential and prolonging the rela-
tive refractory time by approxi-
mately 150%.
Freeman et al. (55) showed that
fish oil supplementation can im-
prove the health status of dogs with
heart failure, reducing Interleukin-
1β(IL1) production and improving
the cachexia that is often associated
with heart failure. IL1 is correlated
with higher mortality rates and this
may be the consequence of the
negative inotropic effect of IL1 or
of the fact that IL1 increases skele-
tal muscle protein turnover and re-
duces cardiac myocyte protein syn-
thesis (56).
The role of PUFA in the treatment
of chronic renal disease in dogs and
Despite the fact that renal disease
is a very common cause of death in
dogs and cats, the causes of renal
disease and its progression are only
poorly understood. In dogs and
cats with renal insufficiency,
glomerular hypertension and hy-
pertrophy are observed (57, 58).
These findings are supposed to
represent the adaptive renal re-
sponse to the injury. Frequently, re-
nal failure with glomerular hyper-
tension is associated with elevation
of systemic arterial pressure of dogs
and cats (59, 60). In dogs with re-
nal failure, preglomerular vessels
are dilated and even transient ele-
vations of systemic pressure are
transmitted to the susceptible
glomerular capillary bed causing
further progression of the disease
Intrarenal hemodynamics are influ-
enced by vasoactive renal eicosa-
noids, such as Prostaglandin E2and
I2and Thromboxane A2(62, 63),
both deriving from AA. While
PGE2and PGI2are powerful va-
sodilators and help maintain renal
blood flow and glomerular filtra-
tion, TXA2reduces renal blood
flow and glomerular filtration and
induces aggregation of platelets
(64). Intrarenal platelet aggregation
may lead to proteinuria due to
higher capillary permeability and to
intraglomerular coagulation with
subsequent fibrosis and sclerosis
(65). Conversely, TXA3,which is
derived from EPA, does not cause
platelet aggregation (66).
Brown et al. (67) fed dogs with re-
nal insufficiency different sources
of fat. Feeding the animals with
safflower oil (rich in omega-6 fatty
acids) enhanced renal injury while
feeding fish oil prevented deterio-
ration of renal function. Dietary
supplementation with beef tallow
(a source of saturated fatty acids)
also produced a progressive decre-
ment of renal function but the rate
of function decline was slower than
in animals receiving safflower oil.
During another study (68), dogs
with early renal insufficiency were
fed safflower oil, fish oil or beef tal-
low. Compared to feeding beef tal-
low, feeding fish oil decreased
serum cholesterol concentration
and PGE2and TXA2excretion,
while dietary supplementation with
safflower oil increased eicosanoids
excretion, glomerular capillary
pressure and glomerular enlarge-
The role of PUFA in the
prevention and treatment of
neoplastic disorders in dogs and
In humans, there is evidence that
omega-3 fatty acids may have some
beneficial effect on some neoplastic
diseases, such as breast, colorectal,
and prostatic cancer, preventing de-
velopment and growth of tumors
and reducing the incidence of
metastatic disease (69-72).
Cachexia is a very common conse-
quence of malignancy and it is
caused by a number of derange-
ments in carbohydrate, lipid and
protein metabolism that are ob-
served in humans (73, 74) as well
as in dogs (75, 76). Since TNF and
interleukin-6 are supposed to play a
role in the pathogenesis of cancer
cachexia (77), feeding fish oil to
cancer patients may reduce the pro-
duction of these eicosanoids and
consequently the incidence of
cachexia (78, 79).
In dogs with lymphoma, dietary
omega-3 fatty acids significantly
increased disease free interval and
survival time (80).
There is evidence from the litera-
ture that the omega-6/omega-3
fatty acid ratio of the diet influ-
ences growth and health status of
dogs and cats. Essential fatty acids
are very important for the develop-
ment of the nervous system and an
optimal dietary omega-6/omega-3
fatty acid ratio (about 6 to 1) re-
duces the incidence of some dis-
eases, such as cancer and sudden
cardiac death. Furthermore, the use
of fatty acid supplements has
proved to be beneficial in the treat-
ment of several pathogenic condi-
tions, such as chronic inflammatory
diseases, atopy, chronic renal dis-
ease, and some types of cancer.
Therefore, particular attention
should be paid to the type and
quantity of fat sources that are used
when diets for dogs and cats are
formulated, in order to assure the
optimal amount and balance of
omega-3 and omega-6 fatty acids
in the food.
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... Fatty acid addition has demonstrated beneficial effects in several species such as horses (Hess and Ross-Jones, 2014), pigs (Rostagno et al., 2017;Liu et al., 2018), dairy cows (NRC, 2001;Harvatine and Allen, 2006), poultry (Poorghasemi et al., 2013;Rostagno et al., 2017) and, especially, management of several diseases and clinical problems in pets (Lenox and Bauer, 2013;Wąsik et al., 2016). Of particular interest are, for example, linoleic (9c12c-C 18:2 ), eicosapentaenoic acid (5c8c11c14c17c-C 20:5 ), and docosahexaenoic acid (4c7c10c13c16c19c-C 22:6 ), (C 20:5 ) in puppy and dog food (Ahlstrøm et al., 2004); relevant for cardiovascular health and nervous system development (Biagi et al., 2004;Fraeye et al., 2012). ...
... In contrast, cats, despite being strictly carnivorous, require an essential input of 5c8c11c14c-C 20:4 . Additionally, pets need, mandatorily, feed ingredients which input 9c12c-C 18:2 (as they are not able to synthesize it from linolenic acid) (Biagi et al., 2004;. During their development, a minimal input of 9c12c-C 18:2, 9c12c15c-C 18:3 , 5c8c11c14c-C 20:4 , 5c8c11c14c17c-C 20:5 , and 4c7c10c13c16c19c-C 22:6 is required (Biagi et al., 2004;. ...
... Additionally, pets need, mandatorily, feed ingredients which input 9c12c-C 18:2 (as they are not able to synthesize it from linolenic acid) (Biagi et al., 2004;. During their development, a minimal input of 9c12c-C 18:2, 9c12c15c-C 18:3 , 5c8c11c14c-C 20:4 , 5c8c11c14c17c-C 20:5 , and 4c7c10c13c16c19c-C 22:6 is required (Biagi et al., 2004;. Values obtained for the above mentioned fatty acids are below 1.00 g kg -1 fat in the dry pet foods analyzed, an expected result as only fish-based pet foods are usually rich in 5c8c11c14c17c-C 20:5 and 4c7c10c13c16c19c-C 22:6 (Biagi et al., 2004). ...
Full-text available
Fatty acid determination is used for the characterization of the lipid fraction in foods, providing essential information regarding feed and food quality. Most edible fats and oils are composed primarily of linear saturated fatty acids, branched, mono-unsaturated, di-unsaturated, and higher unsaturated fatty acids. To attain this information we developed a gas chromatography (GC) method that can separate fatty acids from C4 to C24 using mass spectrometry identification. A simplified sample preparation procedure was applied so it is not time-consuming and short enough to avoid fat degradation. Additionally, one-step derivatization was applied to obtained fatty acid methyl esters in situ in the gas chromatograph injection port, using tetramethylammonium hydroxide and a high polarity polyethylene glycol-based cross-linked microbore chromatographic column was coupled to achieve the separation of 60 compounds in under 15 minutes with extreme sensibility. The versatility of the method allows fatty acid profile (including saturated [SFA], monounsaturated [MUFA], and polyunsaturated fatty acids [PUFA]) information to be gathered in different products of primary production i. raw materials commonly used in the production of animal feed, ii. profiles for balanced feed for laying hens, beef cattle and dairy cattle and iii. products of animal origin intended for human consumption, such as meat, eggs, and milk. Our data (performance parameters and fatty acid profiles) support the validity of the results; the method can be used for quality assurance both in productive species feed and feed ingredients, pet food, and related food matrices. The technique presented herein can be used as a high-throughput routine screening tool to assess fat quality as this data is paramount to improve animal nutrition and health and animal-derived products of human consumption.
... The flesh of oily fish (herring, pilchards, mackerel, sardines, tuna, salmon, and trout) contains significant amounts of vitamins A and D and omega-3 fatty acids. In the last decade, research clearly showed that omega-3 fatty acids had many positive health effects on the immune system, skin and hair coat, cancer, and cognitive function in dogs and cats [20,21]. Omega-3 fatty acids associated with potential health benefits include docosahexanoic acid (DHA), eicosapentanoic (EPA) and alpha-linolenic acid (ALA). ...
... There were no significant differences in protein and ash among the three byproducts used in wet pet food recipes. Even though fat content was not statistically compared, the fat content in salmon (18.04%) and chicken carcass (19.59%) was numerically higher compared to tuna (6.40%), which normally has a higher level of muscle and less fat content [20]. ...
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Simple Summary Fish and fish by-products are excellent sources of high-quality protein for cats and dogs. However, the handling, processing, and storage of raw materials can increase variation and negatively impact their technological properties. This study aimed to evaluate the use of spray-dried animal plasma (SDAP) as a binder in fish by-products recipes for chunks in gravy. The results showed that the inclusion of SDAP in recipes significantly improved the consistency (hardness), elasticity (springiness), cohesiveness, chewiness, and juiciness of the final wet products. These improvements were observed in a chunk recipe with a 35% content of mixed salmon and tuna by-products, and another recipe with chunks having a final content of a 4% salmon by-product. There was a positive linear effect of increased SDAP inclusion in the recipes for most of the technological parameters measured such as elasticity, flexibility, juiciness, and hardness. Our findings indicate that SDAP is an excellent nutritional binder that can enhance the final technological properties of wet pet food products using high-quality fish recipes and potentially in recipes containing protein-rich fish by-products with low functionality. Abstract Spray-dried animal plasma (SDAP) and wheat gluten (WG) are common binders in wet pet food that provide amino acids and energy, as well as texture and cohesiveness due to their gelling strength, water retention and fat emulsion properties. Binder use is a valuable tool especially in recipes based on ingredients with low technological properties such as fish by-products containing spines and scales and soft texture after cooking. Two basal recipes for chunks in gravy were produced to evaluate experimental treatments. One basal recipe used a mixture of salmon and tuna by-products as the only animal protein sources without binders or with a 20 g/kg inclusion of SDAP or WG. The other basal recipe mimicked a more typical commercial recipe containing meat animal ingredients and a 40 g/kg salmon by-product to develop experimental treatments with and 0, 10, 20, 30 or 40 g/kg inclusions of SDAP. Dry matter, protein, and viscosity were evaluated in raw emulsions. After a 1 h retorting at 121 °C, hardness was measured in emulsions and in cooked chunks, juiciness, and Texture Profile Analysis (TPA) were assessed. Results demonstrated the viability of producing quality chunks in gravy containing only fish by-products including 20 g/kg of SDAP, which significantly increased hardness, elasticity, cohesiveness, and juiciness. There was a positive linear correlation of increased SDAP inclusion rate in the commercial recipe for most of the quality parameters evaluated. Based on these results, the inclusion of SDAP in fish recipes can help manufacturers achieve technological quality control targets for commercial wet pet food and may help producers to successfully formulate new recipes for wet pet food products using fish by-products as the sole animal protein source.
... The hempseed cake diet has shown an n-6/n-3 ratio lower than 5:1, which has been claimed as ideal for humans and dogs (22). Polyunsaturated fatty acids are very important for the development of the nervous system, and an optimal dietary n-6/n-3 fatty acid ratio reduces the incidence of some diseases, such as cancer and sudden cardiac death (23). Moreover, it is important to have adequate amounts of DHA and EPA, which are useful for neurologic development, particularly during the early stage of growth. ...
... However, the higher percentage of PUFA could limit diet shelf-life as demonstrated by the increased peroxidation index of the H-diet with respect to the T-diet. Diets that contain a high amount of PUFA must be protected from light and high temperatures that could cause their oxidation during the production process and storage (23). ...
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In the last few years, the popularity of industrial hemp and its products is increased. From a nutritional point of view, hemp and its products are rich in protein, polyunsaturated fatty acids, vitamins, and useful minerals. Nowadays, the European Commission authorizes the use of hempseed and hempseed oil co-products in animal nutrition. This study is aimed to evaluate the use of hempseed cake in dogs' nutrition, comparing the effect of the supplementation of two lipid sources: swine tallow (T-diet) and hempseed cake (H-diet). A double-blind nutritional trial was performed at a municipal kennel located in Naples. Eight crossbreed neutered dogs recognized in good health were recruited and divided into two homogeneous groups (T- vs. H-group). Both diets were analyzed for chemical composition and fatty acid profile. Blood count and biochemical profile were evaluated at recruitment (T0) and the end of the trial (T30). Oleic, palmitic, and stearic acids were the most representative fatty acids in both diets; however, the H-diet contains more than double concentration of linoleic and α-linoleic acids compared to the T-diet ( p < 0.01). The H-diet has shown significantly ( p < 0.01) higher peroxidation index as the only negative aspect, which could compromise its shelf-life. After 30 days of administration, the H-group has shown a significant ( p < 0.01 and p < 0.05) reduction of liver and renal markers [aspartate transferase (AST), alanine transaminase (ALT), and creatinine] and cholesterol, due to the healthier fatty acid profile. Hempseed cake seems a suggestable source of polyunsaturated fatty acids for dogs considering these preliminary results.
... Estes AG são classificados de acordo com o local onde se encontra a primeira dupla ligação a partir do metil terminal da molécula. Os AG n-6 e n-3 são nutrientes essenciais para o crescimento adequado e para prevenção de doenças em mamíferos (Biagi et al., 2004). Estes AG são chamados de "essenciais", pois não são sintetizados em quantidades suficientes pelos animais devido à deficiência de enzimas necessárias para sua síntese e, portanto, devem ser incorporados nas dietas a fim de suprir sua demanda (Case et al., 2011). ...
... Estudos em cães sugerem que a suplementação de PUFA n-3 tem efeito benéfico em animais com dermatite atópica (Olivry et al., 2001), câncer (Ogilvie et al., 2000, doença cardíaca (Billman, et al., 1999), insuficiência renal crônica (Biagi et al., 2004) e doenças inflamatórias (Hall et al., 2005). Entretanto, efeitos adversos como alteração das funções plaquetárias, distúrbios gastrointestinais, retardo no processo de cicatrização, peroxidação lipídica, ganho de peso, alterações na funcionalidade do sistema imune, efeitos no controle glicêmico e sensibilidade à insulina, também têm sido associados com a suplementação excessiva de n-3 (Hall, 1996;Wander et al., 1997;. ...
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The present study evaluated the alterations of the oxidative stress markers in adult dogs fed with high levels of saturated or unsaturated fatty acids, supplemented or not with natural algae based antioxidant. Twelve healthy adult Beagle dogs (6 males and 6 females, 2 years old, 11.2 ± 1.92 kg BW), were distributed in 2 completely randomized blocks and fed with 4 experimental diets coated with 2 lipid sources: saturated (13% bovine tallow) or unsaturated (13% soybean oil enriched with DHA), supplemented or not with with 500 mg of algae- based natural antioxidant (AOX) for 4 weeks, intercalated with a 4 week adaptation period. Blood samples were collected on days 0, 15 and 30 of each block. Glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), sulfhydryl group, protein carbonylation (PC), thiobarbituric acid reactive substances (TBARS) and total reactive antioxidant potential (TRAP) were evaluated in serum. While GSH-Px, SOD, glutathione S-transferase (GST), catalase (CAT), sulfhydryl group and TBARS were measured in erythrocytes. There was no significant difference in most of the oxidative markers evaluated. In contrast, GST activity in erythrocytes was greater in the animals that consumed the diets coated with bovine tallow compared to animals that consumed diets coated with soybean oil enriched with DHA (P < 0.05). Serum from animals fed diets supplemented with AOX presented greater TRAP values (P < 0.05). The data demonstrate that the concentrations of unsaturated fatty acids used in the diets for adult dogs were not sufficient to cause large changes in the oxidative status. It was not possible to evaluate the efficiency of the natural antioxidant in maintaining the oxidative balance of the animals once seems like the body was not challenged by the unsaturated diets. It suggests that dogs descended from carrion carnivore dogs may have some natural protection against oxidation.
... These groups of essential fatty acids are involved in several metabolic processes and structural body functions as fundamental components of cell membranes that participate in the transport of nutrients and metabolites across membranes. Furthermore, they are necessary for regular growth and prevention of several health disorders (e.g., cardiovascular diseases, diabetes, hypertension, chronic inflammatory, autoimmune disorders, and cancer) in mammalians [6]. Most plant oils contain between 80 and 90% of unsaturated fatty acids, while animal fats have between 50 and 60% of unsaturated fatty acids [7]. ...
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Lipids represent a significant energy source in dogs’ diets. Moreover, dogs need some essential fatty acids, such as linoleic and α-linolenic fatty acids, because they are not able to produce them endogenously. This study aimed to evaluate the effect of different dietary lipid sources on faecal microbial populations and activities using different evaluations. Hemp seed oil and swine tallow were tested as lipid supplements in a commercial canned diet at a ratio of 3.5% (HL1 and HL2, respectively). These diets were compared with one rich in starch (HS). Twelve dogs were recruited and equally divided into three groups. Faeces samples at 30 days were used as inoculum and incubated with three different substrates (MOS, inulin, and cellulose) using the in vitro gas production technique. The faecal cell numbers of relevant bacteria and secondary metabolites were analysed (in vivo trial). In vitro evaluation showed that the faeces of the group fed the diet with hemp supplementation had better fermentability despite lower gas production. The in vivo faecal bacterial count showed an increase in Lactobacillus spp. In the HL1 group. Moreover, a higher level of acetate was observed in both evaluations (in vitro and in vivo). These results seem to indicate a significant effect of the dietary fatty acid profile on the faecal microbial population.
... From the nutritional point of view, the distribution of FA in TAG is very important, but even more important, is their composition in the fat. The EFA for cats are LA and AA from the omega-6 group as well as ALA, EPA and DHA belonging to the omega-3 group [40,41]. The role of omega-6 and omega-3 fatty acids in maintaining health is affected by their ratio. ...
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The purpose of the present study was to characterize lipid fraction extracted from five self-prepared and seven commercial cat foods using gas chromatography (GC) and pressurized differential scanning calorimetry (PDSC) techniques. Self-prepared food recipes were composed using BARFny kalkulator, software dedicated for balancing cat diets, and prepared on the basis of fresh raw meat and offal. Extracted fat fractions were compared qualitatively and quantitatively with literature data for the fat of whole prey items to check the main assumptions of the software used. The fatty acid (FA) composition and distribution were determined using GC. The PDSC method was used for the determination of the oxidative stability of extracted fats. The obtained results indicate that self-prepared cat foods contained a high level of essential fatty acids (EFA) but low oxidative stability, especially for those with significant amounts of polyunsaturated FA. The FA profile and oxidative stability were examined for four dry and three wet commercial cat foods. It was found that their omega-6 to omega-3 ratio was beneficial reaching 5.3:1 to 10.1:1, despite the low amount of EFA. The longer induction time was determined for fats extracted from commercial cat foods than for self-prepared ones, which indicate their higher oxidative stability.
... The use of LCPUFA n-3 supplements in animal diets is not limited to enriching tissues to produce functional foods for human consumption; such supplements are also employed in the preparation of pet foods (Biagi et al., 2004) and possibly of livestock feeds as well, with the aim, however, of improving the reproductive performance and health of mothers and offspring (Mordenti et al., 2005). ...
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A study was conducted on a total of 240 primiparous does and their 1184 kits. Does were divided into two experimental groups of 120 each and their kits into four groups. Does were all submitted to artificial insemination on the same day; both groups were fed commercial diets supplemented respectively with coconut oil (2g/kg) and dehydrated alfalfa (2g/kg) (Group D−) or cultivated single-cell marine algae (4g/kg) characterized by a high content of long-chain polyunsaturated fatty acids (LCPUFA) (primarily docosahexaenoic acid, DHA) (Group D+). Kits born from the 200 does that became pregnant (100 in the first group and 100 in the second) were assigned to 4 experimental groups (2 treated and 2 controls) and received, like their mothers, commercial diets with or without LCPUFA supplementation. Results showed a substantial similarity in the reproductive efficiency of does and zootechnical and slaughtering performances of growing–fattening rabbits. The quality of loin and thigh lipids also were influenced not only by the presence of algae in the feeds administered to weaned and finishing rabbits, but also by n-3 LCPUFA supplementation in the mothers' diet.
... Concerning commercial dog food, it seems likely that in dogs deficiencies of PUFA are rare as long as fat oxidation during process and storage of the food is limited 107 . Levels of PUFA, particularly the n-3 family, are nowadays higher in commercial dog food compared to foods of several years ago 108 (Delton-Vandenbroucke et al., 1998). ...
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Each year, millions of dogs worldwide are abandoned by their owners, relinquished to animal shelters, and euthanised because of behaviour problems. Nutrition is rarely considered as one of the possible contributing factors of problem behaviour. This contribution presents an overview of current knowledge on the influence of nutrition on canine behaviour and explores the underlying mechanisms by which diet may affect behaviour in animals. Behaviour is regulated by neurotransmitters and hormones, and changes in the availability of their precursors may influence behaviour. Tryptophan, the precursor of serotonin, may affect the incidence of aggression, self-mutilation and stress resistance. The latter may also be influenced by dietary tyrosine, a precursor to catecholamines. As diet composition, nutrient availability and nutrient interactions affect the availability of these precursors in the brain, behaviour or stress resistance may be affected. PUFA, especially DHA, have an important role as structural constituents in brain development, and dietary supply of n-3 and n-6 PUFA could modify aspects of the dopaminergic and serotonergic system and, consequently, cognitive performance and behaviour. Finally, persistent feeding motivation between meals can increase stereotyped behaviour and aggression and decrease resting time. This feeding motivation may be altered by dietary fibre content and source. At present, few studies have been conducted to evaluate the role of nutrition in canine (problem) behaviour through the above mentioned mechanisms. Studies that explore this relationship may help to improve the welfare of dogs and their owners.
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The purpose of this study was to determine whether the dose of (n-3) fatty acids (FA) administered, independent of the relative ratio of (n-6) to (n-3) FA in the food, influences plasma FA composition in dogs. Healthy female, geriatric beagles (7-10 y old) were fed foods containing (n-6) to (n-3) FA ratios of either 40.0:1 or 1.4:1 for 12 wk (study 1) or 36 wk (study 2). In study 3, beagles were fed food with the same 1:1 ratio of (n-6) to (n-3) FA, but with increasing concentrations of (n-6) and (n-3) FA. Plasma FA concentrations were measured after completing the feeding studies. In studies 1 and 2, dogs fed fish oil-enriched food with a high (n-3) FA concentration had higher plasma total (n-3) FA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) concentrations and lower plasma total (n-6) FA, linoleic acid, and arachidonic acid concentrations than dogs fed corn oil-enriched food with a low (n-3) FA concentration (P < 0.001). Both inclusion of fish oil (P < 0.001) and increased food intake independent of treatment effects increased the plasma DHA (P = 0.05) concentration. Furthermore, constancy of the dose of (n-3) FA administered over long periods of time was necessary to maintain plasma levels of total (n-3) FA, EPA, and DHA. In study 3, up to certain dietary concentrations (6.3 g total (n-3) FA/kg food for DHA and 9.8 g total (n-3) FA/kg food for EPA), the dose of (n-3) FA administered, independent of the (n-6) to (n-3) FA ratio, determined the plasma (n-3) FA composition. Results from our studies indicate that approximately 175 mg DHA/(kg body weight . d) is required to attain maximum plasma levels of DHA.
Recent research has suggested that an increased (n-3) fatty acid intake and/or increased (n-3)/(n-6) polyunsaturated fatty acid (PUFA) ratio in the diet is associated with a lower breast cancer risk. This case-control study investigated the association between intake of (n-3) and other fatty acids and the (n-3)/(n-6) PUFA ratio and breast cancer risk. After combining data from two related case-control studies in Connecticut, we had information available on a total of 1119 women (565 cases and 554 controls). Cases were all histologically confirmed, incident breast carcinoma patients. Controls were hospital-based (Yale-New Haven Hospital study site) and population-based (Tolland County study site). Information on dietary intake was obtained through a validated food-frequency questionnaire. Standard multivariate methods were used to address the independent effects of specific fatty acids, fat classes and macronutrients on breast cancer risk. In the full study population, there were no significant trends for any macronutrient/fatty acid when comparing the highest to the lowest quartile of intake. When the analysis was restricted to premenopausal women, consumption of the highest compared with the lowest quartile of the (n-3)/(n-6) PUFA ratio was associated with a nonsignificant 41% lower risk of breast cancer [odds ratio (OR) = 0.59, 95% confidence interval (CI) 0.29, 1.19, P for trend = 0.09]. A higher (n-3)/(n-6) PUFA ratio was significantly associated with a lower risk of breast cancer when the data were restricted to the Tolland County (population-based) study site; OR = 0.50, 95% CI 0.27, 0.95, P for trend = 0.02. These results are consistent with the hypothesis that a higher (n-3)/(n-6) PUFA ratio may reduce the risk of breast cancer, especially in premenopausal women.
The brain is 60% structural lipid, which universally uses arachidonic acid (AA; 20:4n−6) and docosahexaenoic acid (DHA; 22:6n−3) for growth, function, and integrity. Both acids are consistent components of human milk. Experimental evidence in animals has demonstrated that the effect of essential fatty acid deficiency during early brain development is deleterious and permanent. The risk of neurodevelopmental disorder is highest in the very-low-birth-weight babies. Babies born of low birth weight or prematurely are most likely to have been born to mothers who were inadequately nourished, and the babies tend to be born with AA and DHA deficits. Because disorders of brain development can be permanent, proper provision should be made to protect the AA and DHA status of both term and preterm infants to ensure optimum conditions for the development of membrane-rich systems such as the brain, nervous, and vascular systems.
The pathologic changes of essential fatty acid (EFA) deficiency were studied in specific-pathogen-free, domestic shorthair cats which were fed purified diets for 1.5 to 2.5 years. Cats fed an EFA-deficient diet exhibited signs of deficiency: severe fatty degeneration of the liver, excessive fat in the kidneys, dystrophic mineralization of the adrenal glands, degeneration of the testes, and hyperkeratosis of the skin. Minor clinical pathologic changes were consistent with liver damage. Fatty acid analyses of plasma lipids revealed low concentrations of linoleate and other n6-fatty acids, and high concentrations of n7- and n9-fatty acids, consistent with EFA deficiency. These signs of deficiency were prevented by including safflower seed oil in the diet at a concentration to supply linoleate at 6.7% of dietary energy. Therefore, linoleate is an EFA for the cat, despite negligible conversion of linoleate to arachidonate in cat liver. However, in cats fed a diet containing linoleate, but lacking arachidonate, there was mild mineralization of the kidneys, and the neutral fat content of the liver was slightly higher than that of cats fed a diet containing arachidonate and other long-chain polyunsaturated fatty acids. Also, 2 of the 19 cats fed arachidonate-deficient diets developed unusual inflammatory skin lesions. In cats fed a diet containing hydrogenated coconut oil, safflower seed oil, and chicken fat, fatty livers developed despite the presence of high levels of linoleate. The fatty livers appeared to result from a specific deleterious effect of the medium-chain triglycerides in hydrogenated coconut oil. Most of the organ pathologic changes of EFA deficiency in the cat can be prevented by feeding dietary linoleate. Linoleate meets the EFA requirement for functions which depend on proper membrane structure: growth, lipid transport, normal skin and coat condition, and maintenance of the epidermal permeability barrier. However, dietary arachidonate is required by the cat for functions which depend on eicosanoid formation, such as reproduction and blood platelet aggregation.
Dietary n-3 polyunsaturated fatty acids are widely used for amelioration of inflammatory skin disease in dogs. In this study, a diet containing two different sources of n-3 polyunsaturated fatty acid–triglyceride (from menhaden oil) and concentrated ethyl esters–was fed to one group of six purpose-bred dogs, while an isocaloric isonitrogenous diet with corn oil (n-6 polyunsaturated fatty acids) was fed to another group of eight purpose-bred dogs for six weeks. Peripheral blood neutrophils, isolated at week–1 (baseline), week 2 and week 6, were stimulated with calcium ionophore A23187 and the amount of leukotriene B4 produced was determined via reversed-phase high performance liquid chromatography. Analysis of variance of log-transformed data revealed a significant effect for diet (P = 0.005) at six weeks, with dogs fed the high n-3 polyunsaturated fatty acid diet having significantly less mean ex vivo neutrophil leukotriene B4 production than dogs fed the high n-6 polyunsaturated fatty acid diet. Further studies on the clinical usefulness of n-3 polyunsaturated fatty acid ethyl esters are warranted.