Influence of Dietary Flaxseed Oil on the Performance, Muscle Protein Deposition, and Fatty Acid Composition of Broiler Chicks

Influence of Dietary Flaxseed Oil on the Performance, Muscle Protein Deposition, and Fatty Acid Composition of Broiler Chicks J. M. OLOMU1 and V. E. BARACOS2 Department of Animal Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada (Received for publication October 5, 1990)

1991 Poultry Science 70:1403-1411 INTRODUCTION

Flaxseed oil (FSO) contains about 50% oclinolenic acid (Cig^^), making it the richest terrestrial source of a>3 fatty acids. Dietary ©3 fatty acids are the subject of current interest, because they have been credited with a number of beneficial effects in humans and animals, such as reducing heart disease, reducing circulating cholesterol levels, and suppressing inflammation (Klatt, 1986). The biological activities of ©3 fatty acids depend upon their metabolism and upon their incorporation into tissue lipids. Studies with swine (Cunnane et al, 1990), laboratory rodents (Lee et al., 1988; Garg et al., 1988), and broiler chickens (Phetteplace and Watkins, 1989) have examined the effects of FSO on fatty acid profiles of various tissues. These authors have reported a general increase in the tissue and organ contents of Cig^og and its metabolism to longer chain and further desaturated derivatives (C20:5. C22:5, and C^rf)For poultry production FSO might serve as an alternative source of dietary energy, as well

*On sabbatical leave from the Faculty of Agriculture, University of Benin, P.MJB. 1096, Benin-City, Nigeria. •T'o whom correspondence should be addressed.

as a concentrated source of essential fatty acids. Flaxseed oil contains about 50% linolenic acid and 15% linoleic acid. In addition, the use of FSO as a feed ingredient may lead to the incorporation of polyunsaturated fatty acids, particularly co3 fatty acids, into tissues. This may make chickens so fed an alternative to marine fish as a potential source of co3 fatty acids in human diets. Furthermore, recent work suggests that co3 fatty acids may affect muscle protein synthesis and protein deposition through a prostaglandin-dependent mechanism (Palmer, 1990). However, few studies have been conducted on the effects of FSO on performance, lipid and protein contents, and the fatty acid status (especially co3 fatty acid) of broiler chickens. Some studies with different fat sources have shown that the performance of broiler chickens may be influenced by the type of supplementary fat in the diet. For example, Hulan et al. (1984) reported similar performances for various types of animal fat, but noted that combinations of canola oil and animal fat improved performance relative to animal fat alone. Watkins (1989) reported better feed conversion efficiency in broilers fed maize oil or hydrogenated soybean oil, compared with those fed spent restaurant grease. This differ-

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ABSTRACT Experiments were conducted to assess the effect of feeding flaxseed oil on the performance, muscle protein deposition, and fatty acid composition of broiler chicks. Four levels of dietary flaxseed oil were fed in combination with animal tallow to give a total of 6% added fat in the diets. The diets were isonitrogenous and isocaloric. Mortality, weight gain, feed consumption, and feed efficiency were not significantly different among treatments. Dietary treatments had no significant effects on the relative weights of the Extensor digitorum communis and Sartorius muscles nor on their protein or lipid contents. Feeding flaxseed oil resulted in increased accumulation of w3 fatty acids in skeletal muscle lipids. Increased amounts of desaturation and elongation products (C20:3. C20:5» C22:5> and C22:6) o f a-linolenate ( C i g ^ ^ ) were observed in the Sartorius muscle lipids of chicks fed flaxseed oil. Amounts of these 0)3 fatty acids increased with duration of feeding. The amounts of C20:3> C20:4) w e r e significantly depressed in muscle lipids after 21 days of feeding flaxseed oil. The effects of flaxseed oil on tissue amounts of individual saturated fatty acids were minimal, but amounts of monounsaturated fatty acids, especially Cjg : i, were depressed. (Key words: chicken, flax, protein, omega-3 fatty acid, skeletal muscle)

1404

OLOMU AND BARACOS TABLE 1. Percentage composition of experimental diets

Ingredients and calculated composition

53.75 34.60 1.50 1.60 .35 2.00 .20 6.00 22.00 3,164 .86 1.20 1.00 .46

2

3

4

53.75 34.60 1.50 1.60 .35 2.00 .20 4.50 1.50 22.00 3,164 .86 1.20 1.00 .46

53.75 34.60 1.50 1.60 .35 2.00 .20 3.00 3.00 22.00 3,164 .86 1.20 1.00 .46

53.75 34.60 1.50 1.60 .35 2.00 30 150 450 22.00 3,164 .86 1.20 1.00 .46

1

18% calcium, 21% phosphorus. Vitamin and mineral premix supplied the following per kilogram of diet vitamin A, 4,000 IU; vitamin D 3 600ICU; vitamin E, 10 IU; menadione, 1 mg;riboflavin,5 mg; calcium pantothenate, 10 mg; niacin, 20 mg; choline chloride, 100 mg; folic acid, 1 mg; vitamin B 1 2 , 10 (ig; Mn, 108 mg; Zn, 72 mg. 3 Ethoxyquin, at .025% of the diet, was added to the dietary fats before mixing, as an antioxidant 2

ence was dependent upon the level of biotin in under continuous light Feed and water were the diet. Other workers (Atteh et al., 1983; provided for ad libitum consumption. Sklan and Ayal, 1989) found no differences in Two experiments were conducted. In Experformance among broilers fed different types periment 1, birds were fed the experimental of fat with different degrees of saturation. diets for 7 days. Experiment 1 was repeated, None of these studies have compared FSO once using day old birds and once using alone or in combination with other fats in 7-day-old birds. In Experiment 2, birds were broiler diets. The present studies were there- given the dietary treatments on the day of fore designed to determine the effects of FSO hatching and were fed for a period of 21 days. on the performance, muscle growth, and co3 At the start of each experiment, birds were fatty acid incorporation into skeletal muscle of weighed individually and divided into groups broiler chicks. of 12 (Experiment 1) or 24 birds (Experiment 2) such that the average body weight and weight range were similar for each group. MATERIALS AND METHODS Three such groups were given each dietary The experiments conducted conformed to treatment. Equal numbers of male and female the guidelines of the Canadian Council on chicks were used per group in Experiment 1, Animal Care. Broiler chicks of the Hubbard and when it was determined that there were no strain, vaccinated for Marek's disease, were sex-dependent differences, only male chicks obtained on the day of hatching from The were used in Experiment 2. Cooperative Hatchery, Edmonton, Alberta, The diets used were formulated to be Canada. The chicks were housed in thermostat- isonitrogenous (22% crude protein) and isocaically controlled, electrically heated batteries loric (3,164 kcal/kg of diet) with similar (33 to 35 C) wim raised mesh floors and amounts of calcium and phosphorus (Table 1). stainless steel waterers, feeders, partitions, and The basal diet was a com and soybean meal spring locked gates. Birds were maintained diet The diets contained 6% added fat, consisting of 6% animal tallow (AT); 4.5% AT and 1.5% flaxseed oil (FSO); 3.0% AT and AT and 4.5% FSO ••Omega Nutrition Inc. Vancouver, BC, V5X 3E8, 3.0% FSO; and 1.5% (Table 1). Fresh FSO3 (cold-pressed), stored in Canada.

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Com Soybean meal Limestone Dicalcium phosphate NaCl Vitamin and mineral premix DL-methionine Animal tallow^ Flaxseed oil Crude protein ME, kcal/kg Met + Cys Lysine Calcium Available P

Diets 1

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FLAXSEED OIL IN BROILER DIETS

Northern Alberta Processors, Edmonton, AB, T8A 2A6, Canada. Model 3400, Varian Associates Inc., Sunnyvale, CA 94086. ^ternational Scientific, Folsom, CA 95630. 'Hewlett Packard Series 3353, Avondale, PA 19311. 8 Sigma Chemical Co., St Louis, MO 63178-9916. 9 Supelco Inc., Bellefonte, PA 16823.

230 C. Conditions were chosen to separate fatty acids from 12 to 24 carbons in chain length. Fatty acids were identified by comparison of retention times with known standards,8,9 and the results expressed as a percentage distribution of fatty acid methyl esters. The data obtained from the experiments were analyzed by one-way or two-way analysis of variance and significant differences between means determined by Duncan's multiple range test (Steel and Torrie, 1980). The criterion for significance was a probability of .05. RESULTS

Table 2 shows the fatty acid contents of the oils and lipids of the diets fed. No fatty acids longer than 22 carbons were detected in the feed or fat samples. Weight Gain, Feed Consumption, Feed Efficiency, and Muscle Weights For feeding periods of 7 or 21 days, there were no differences among treatments in weight gain, feed consumption, or feed efficiency. The weights of the two muscles studied, relative to body weight, were also unaffected by dietary treatments. Essentially identical data were obtained when Experiment 1 was repeated; data presented in Table 3 were obtained from chicks fed the experimental diets starting on the 7th day after hatching. Pooled data for male and female birds are presented. Data in Table 4 were based on male chicks fed from hatching until 21 days of age. Protein and Lipid Contents of the Muscles Percentage protein and lipid content did not differ significantly among dietary treatments, when chicks were fed the experimental diets for 7 or 21 days (Tables 3 and 4). However, protein as a percentage of the muscle weight increased significantly with age on all dietary treatments. Sex of chicks had no significant influence on any of the parameters studied. Fatty Acid Composition of Sartorius Muscle Lipids Results from Experiment 1 are presented in Table 5. Sex of chicks had no significant effects

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light and (Vtight bottles, and animal tallow4 rendered from slaughterhouse waste at 118 C were used. Diets were prepared weekly and stored at - 4 C. Diets were consumed ad libitum for a period of 7 days (Experiment 1) or 21 days (Experiment 2). In Experiment 1, Diets 1 to 4 (Table 1) were tested Diet 3 was not included in Experiment 2. Individual body weights were recorded weekly. Feed consumption was also recorded weekly for each replicate (one battery pen). On Days 7 (Experiments 1 and 2) and 21 (Experiment 2), four birds were taken from each replicate and killed by cervical dislocation. The Extensor digitorum communis (EDC) muscles from the wing and Sartorius muscles from the thigh were dissected, weighed, and then stored at -30 C until analyzed. Muscle protein was determined by the Kjedahl method (Association of Official Analytical Chemists, 1990). The two muscles used were chosen represent different metabolic profiles. The EDC is characterized by glycolytic metabolism, and the Sartorius is oxidative. The present authors have used the EDC extensively for in vitro studies (Baracos et at., 1989). Total lipid was extracted with chloroformmethanol (2:1) from one of me two Sartorius muscles from each chick according to die method of Folch et al. (1957). The lipid extracted was evaporated to dryness at 60 C under nitrogen for determination of total lipid content. The lipid extracts were then converted to fatty acid methyl esters using a mixture of boron trifluoride (in 10% methanol), hexane, and methanol (35:20:45, vol/vol/vol) (Morrison and Smith, 1964). The resultant fatty acid methyl esters were separated and quantified by automated gas liquid chromatography5 equipped with autosampler, flame ionization detector, fused silica capillary column (30 m x .25 mm internal diameter),6 and integrator.7 Helium was used as the carrier gas at a flow rate of 3.0 mL/min. The column temperature was increased from 60 to 230 C at a rate of 30 C/min up to 160 C and then at 5 C/min up to

1406

OLOMU AND BARACOS TABLE 2. Fatty acid composition of animal tallow, flaxseed oil, and diets as fed (percentage of total fatty acidsr

Fatty acids3 c

Flaxseed oil

Diet 1

Diet 2

Diet 3

Diet 4

1.9 ND 4 20.8 2.3 .7 11.6 5.4 43.7 3.1 7.4 1.5 .8 .8 ND 35.8 8.9 7.4 1.5

.1 ND 6.0 .3 ND 4.0 ND 21.5 .9 15.6 51.0 .3 .3 ND 10.4 66.6 15.6 51.0

1.0 .1 17.3 1.6 .6 10.3 4.7 35.7 2.1 23.1 2.0 .6 .7 2 30.2 25.1 23.1 2.0

.8 .1 14.8 1.2 A 8.2 3.3 35.7 1.6 25.3 10.7 .5 .5 2 25.2 36.0 25.3 10.7

.5 .1 12.5 1.0 .3 7.3 2.3 29.3 1.4 25.5 18.6 .5 .5 2 21.4 44.1 25.5 18.6

.4 .1 11.0 .6 2 5.4 1.2 26.7 1.1 25.8 26.5 .4 .4 2 17.8 52.3 25.8 26.5

1

The values presented ate means of duplicate determinations. No fatty acids longer than 22 carbons were detected in the feed or fat samples. 3 SAT = saturated fatty acids; PUFA = polyunsaturated fatty acids. = none detectable. 2

on fatty acid profiles, and the results presented represent the pooled data for males and females. A small amount of unidentified fatty acids were observed (1 to 2% of the total); these are denoted "others" in the tables. Chick Sartorius muscle

lipids contained 33 to 37% saturated fatty acids, predominantly Cig:o and Cig:o. The tissue content of saturated fatty acids was relatively insensitive to the diet. However, at the highest levels of dietary FSO, there was a tendency for

TABLE 3. Effects of dietary flaxseed oil on body weight gain, feed efficiency, and muscle parameters of broiler chicks (Experiment If

Weight gain, g per bird Feed intake, g per bird Feed efficiency, g:g EDC muscle,4 mg/100 g BW % protein Sartorius muscle, mg/100 g BW % protein % lipid 1

Diet 1 6% AT 3 0% FSO

Diet 2 4.5% AT 1.5% FSO

Diet 3 3.0% AT 3.0% FSO

Diet 4 1.5% AT 4.5% FSO

170.4 217.6 1.3

162.6 212.4 1.3

157.9 206.6 1.3

173.4 220.0 1.3

3.78 5.70 .03

20.8 15.6

20.3 14.1

20.7 14.2

21.2 14.4

.53 .44

273.3 11.8 25

256.3 11.9 3.5

273.3 12.0 3.4

268.6 12.3 3.4

11.2 52 .16

SD

Three replicates of 12 birds were offered the experimental diets starting on Day 7 after hatching, and the parameters above determined during 7 days of feeding. Pooled data for male and female birds are presented. 2 No significant differences were detected among means within each row (P>.05). 3 AT = animal tallow, FSO = flaxseed oil. 4 EDC = Extensor digitorum communis muscle.

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14:0 Cl5:0 C 16:0 C 16:l Cl7:0 C 18:0 ClkUtram) C 18:lco9 C 18:la>7 c 18:2a>6 c 18:3co3 020:0 c 20:lco9 c 22:0 2 SAT X. PUFA 2 0*5 2 0)3

Animal tallow

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FLAXSEED OIL IN BROILER DIETS TABLE 4. Effects of dietary flaxseed oil on body weight gain, feed efficiency, and some muscle parameters of broiler chicks (Experiment 2)

Variable

Diet 2 4.5% AT 1.5% FSO

Diet 4 13% AT 43% FSO

SD

96.0 514.1

91.4 500.7

93.7 510.0

3.13 17.8

115.6 786.8

106.6 739.4

111.7 762.3

330 325

1.20 1.51

1.17 1.44

1.19 1.51

20.3 18.4

20.6 19.2

21.8 18.3

2495 258.3

2583 257.0

240.8 248.3

.02 .03 1.67 1.13 155 11.4

15.1b 203*

15.1b 18.8a

16.1b 19.3a

1.09 1.46

17.0b 19.2a

17.0ab 19.4a

17.9* 18.7a

.41 .39

6.1 a 5.1 a

6.0* 5.7a

5.2" 5.4 a

.92 .60

a b

> Values in the same column and variable with no common superscript are significantly different (P<05). Three replicates of 24 birds were offered the diets on the day of hatching. Four birds from each replicate were killed at each time and muscles dissected. 2 AT = animal tallow; FSO = flaxseed oil. TJDC = Extensor digitorum communis muscle. 1

amounts of individual saturated fatty acids to be reduced. The Sartorius muscle lipids of chicks fed AT contained 43.4% monounsaturated fatty acids, mostly C i s ; ^ . The tissue content of monounsaturated fatty acids was depressed by feeding FSO, in a dose-dependent fashion. This was particularly the case for Ci8:i. Chick muscle lipids contained 18% polyunsaturated fatty acids when AT was the only fat in the diet; this was increased by feeding FSO to as much as 30% polyunsaturated fatty acids in tissue lipids (Table 5). Alpha-linolenic acid (Cl8:3eo3). the principal constituent of FSO, increased from less than 1% of muscle lipids to 8.9% at the highest level of FSO feeding. This fatty acid comprised 47% of total 3. and Q22:6<»3» were not present in any of the diets and were found in very low amounts in muscle lipids of chicks fed

AT. The addition of FSO to the diets increased the tissue content of these fatty acids, in a dosedependent fashion, but this increase was not as great as in the case of Cig^^. Tissue contents of individual and total o>6 fatty acids were not different among treatments. The effects of feeding the experimental diets for 7 and 21 days (Experiment 2) are shown in Tables 6 and 7. For clarity, the data are divided into saturated and monounsaturated fatty acids (Table 6) and polyunsaturated fatty acids (Table 7). The Cis^toms) found in muscle lipids in Experiment 2 was identified using a standard that was not available at the time that Experiment 1 was conducted. This fatty acid was traced to the AT used in this trial. Some additional o>3 (Ci8:4a>3 and C20:3a>3) and ©6 (C20:2(D6 and C20: 30)5) fatty acids were recorded in this experiment, as standards were available to identify them when Experiment 2 was conducted. The fatty acid profiles seen at 7 days of feeding in Experiment 2 (Tables 6 and 7) were similar to those obtained in Experiment 1 (Table

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Weight gain, g per bird Day 0 to 7 Day 0 to 21 Feed intake, g per bird Day 0 to 7 Day 0 to 21 Feed efficiency, g:g Day 0 to 7 Day 0 to 21 EDC muscle weight, mg/100 g BW 3 Day 7 Day 21 Sartorius muscle weight, mg/100 g BW Day 7 Day 21 EDC muscle, % protein Day 7 Day 21 Sartorius muscle, % protein Day 7 Day 21 Sartorius muscle, % lipid Day 5 Day 21

Diet 1 0% AT 2 0% FSO

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OLOMU AND BARACOS

TABLE 5. Effects of flaxseed oil on the fatty acid composition of the Sartorius muscle (Experiment I)1

Fatty acid c

.7" .1" 22.4" .9" 2.8" .3* 13.3" 35.9" 3.1" 13.2" .9* .5" .7" 2.4" .2 b .4" 5" .3 b .5 b 1.2" 37.3" 43.4" 18.1d 1.9d 16.2»b

Diet 2 4.5% AT 1.5% FSO .7" .1" 23.2" .9" 2.8" .3" 135" 34.0" 2.6b 13.1" 32° .4" .6" 1.8" .4 b 2* .1" .4 b .5 b 1.2" 38.2" 40.9" 19.7° 4.5C 15.2b

Diet 3 3.0% AT 3.0% FSO

J> .1" 21.0" .8" 2.7" 2" 13.0" 30.5 b 2.3 b 15.5" 5.9 b .4" .5" 2.3" .8" .3" .2" .9" .8" 1.3" 35.2 b 36.8 b 26.7 b 8.4 b 18.3 ab

Diet 4 1.5% AT 4.5% FSO

SD

b

.5 .1" 20.2" .7" 2.8" 2* 11.0" 30.1 b 2.4 b 16.2" 7.9" .4" .6" 2.3" 1.0" .4" .2" 1.0" .9" 1.1"

.12 .03 3.17 2% .60 .02 253 22% 27 3.16 1.60 .10 .15 .38 24 .16 .08 26 25 .32

32.4b 36.6b 29.9" 10.8" 19.1"

1.32 .67 .63 .41 .94

a-d'Values in the same TOW with no common superscripts are different (P<05; n = 12).

'SAT = saturated; MUFA = monounsahuated; PUFA = polyunsaturated fatty acids; AT = animal tallow, FSO = flaxseed Oil.

5). With extended feeding of the experimental diets for 21 days, fatty acid profiles of Sartorius muscle lipids showed similar effects of diet as seen after 7 days of feeding, except that the magnitude of the differences between treatments tended to increase. The saturated fatty acids that tended to change with time were C ^ Q and Cig.Q, the decline of which contributed to a decrease of total saturated fatty acid content over time. Individual and total amounts of monounsaturated fatty acids were not affected by me duration of feeding. Total polyunsaturated fatty acids in muscle lipids increased slightly between 7 and 21 days of feeding (Table 7). Total ©3 fatty acids increased as a proportion of total lipids from 7 to 21 days of feeding, especially on the highest level of FSO fed. This increase was mostly due to increased amounts of cc-linolenic acid. As seen in the first experiment with 7 days of feeding, amounts of C18:2
significant depression of the concentrations of Q20:2ca6> Q20:3oa6. Q20:4 and C22:4
pronounced with an increase in the level of FSO. DISCUSSION

Chicks fed diets containing FSO showed similar weight gain, feed consumption, and feed conversion compared with chicks fed diets containing AT, a conventional fat product used in broiler meat production. This was not surprising because the diets were balanced with respect to the required nutrients and FSO is not known to contain any deleterious factors. The present results also demonstrate that the presence of 0)3 fatty acid in the diets in the form of FSO had no effect on muscle protein deposition, at least in the EDC and Sartorius muscles. The lipid content of the Sartorius muscle differed neither among dietary treatments nor between males and females. These observa-

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14:0 15K) c 16:0 c 16:l7 c lt:2ta6 Cl8:36 C22:5o>6 Q22:5
Diet 1 6% AT 0% FSO

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FLAXSEED OIL IN BROILER DIETS TABLE 6. Effects of flaxseed oil on the saturated and monounsaturated fatty acid composition (% wt/wt) of the Sartorius muscle (Experiment 2)1

Fatty acid

C

14K) Cl5:0 Cl6K) C

16:1
c

Diet 2 4.5% AT 15% FSO

Diet 4 1.5% AT 4.5% FSO

.7" .1* 22.3" .5* 4.3" .3* 9.6* 1.7* 36.2* 3.2* .1* 3* 1.3* 33.1" 46.4"

.6* .1" 21.9" .4" 4.3" 2h 8.9" 1.3b 34.2*b 2.5 b .1* .4 b 15* 31.8b 43.1 b

.4 b .1" 19.8* .4* 3.6*

.8* .1* 19.1** .6" 3.8** .3* 9.1* 2.4* 36.2* 3.2* .1* .5* 2.1* 29.5** 46.7*

.7* .1* 185** .5" 3.5"* 2h 8.3 b 1.9b 34.1* 1.9b .1* .4 b 1.7b 27.6"* 42.3 b

ab

8.9*

.6°

29.8 b 2.3 b .2* .3 C 1.2* 29.6° 37.0=

SD

.03 .03 1.06 .05 .80 .02 .86 .16 1.73 0.15 .04 .01 .06 .40 .48

91

Cl4:0 Cl5:0 Cl6K) Cl6:l7 c 17:0 Cl8:0 C 18:l(tran») Cl8:lco9 C 18:la>7 C20.-0

C20:l«o9 Others 2 SAT 2 MUFA

.5° .1" 16.5** .5* 3.5** .lc 7.0°*

.9°

305b 1.9b .1* .3C 1.5b

1 24.3ib* 37.3C

.04 .01 1.10 .08 .67 .03 32 21 1.44 .64 .02 .02 .04 25 .44

""'Means in a row with no common superscripts are significantly different (P<05, n = 12). *SAT = saturated; MUFA = monounsaturated fatty acids; AT = animal tallow; FSO = flaxseed oil. •Significantly different from Day 7 (P<.05).

tions are consistent with earlier findings of Hulan et al. (1988), who showed that the use of another source of 0)3 fatty acid, red fish oil, did not affect the lipid content of breast and thigh meat of broiler chickens. Phetteplace and Watkins (1989) found no differences in the lipid content of thigh and breast meat in broiler chickens fed FSO, menhaden oil, soybean oil, or chicken fat Although tissue lipid levels were not affected by the diets used here, fatty acid composition was altered by the addition of FSO to the diets. Muscle tissue lipids showed considerable plasticity in the pattern of fatty acid incorporation, when chicks were fed fats of varying compositions. Flaxseed oil feeding provoked decreases in the amounts of saturated

and monounsaturated (especially Cig-i) fatty acids in the Sartorius muscle. These decreases were small, suggesting that the deposition of both saturated and monounsaturated fatty acids is required, and is achieved by de novo synthesis in spite of their amounts in the diet. The addition of FSO to the diets resulted in increased accumulation of 0)3 fatty acids in Sartorius lipids, and this increased with the duration of feeding. In a previous study, Phetteplace and Watkins (1989) had shown incorporation of a>3 fatty acids form FSO into chicken muscle lipids after an extended period (56 days) of feeding. In the present study, after 1 wk of feeding diets containing FSO, the Sartorius lipids contained 2.0, 6.3, and 13.6% 0)3 fatty acids respectively, for diets containing

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16:lco7 Cl7:0 Cl8:0 c 18:l(tians) c 18:la>9 c 18:lo>7 QifcO 020:1(09 Others 2 SAT 2 MUFA

Diet 1 6% AT 0% FSO

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OLOMU AND BARACOS TABLE 7. Effects of flaxseed oil on the (tt3 and (0-6 fatty acid composition (% wt/wt) of the Sartorius muscle (Experiment 2)1

Fatty acid

Diet 2 4.5% AT 1.5% FSO 4.7 b .la

.9°

.la .0 b .lc 2b .7 b 14.0* .3 a 2" 22* .3 a .2 a 192b 2.0° 17.2a

jab

.3 b .4 b .7 a 15.1 a 2* .2 a 1.8a 2* .la 23.9 b 6.3 b 17.6a ....

c

18:33 C20:3c»3 C20:5to3 ^2:50)3 ^2:60)3 Cl8:2o>6 ^20:20)6 C20:3
_

62

•tab

Kb*

7b*

17.4a

16.3a .4 a .4a* 2.1 a .3 a .la 21.7°

3 b* 1.6'b*

28.4" 8.8 b 19.6a

2.1C

19.6

a

SD

11.0® 2* .2 a .6 a .7 a .9" 15.8a 2* .2" 2.1 a 2* .la 32.2a 13.6" 18.6a

.99 .05 .02 .05 .07 22 .90 .03 .04 .58 .06 .04

14.4a* .3 a 2* .9** .9 s * .8 a

1.62 .03 .04 .09 .07 .14

17.7a 2b .3 b * l.l c * .lb .0* 36.9s* 17.5a* 19.4a

1.05 .02 .03 24 .03 .05 2% .33 22

.46 23 .71

Ol

[ b*

1.0° .3 a * .0 b 2C .3° .3 b

Diet 3 1.5% AT 4.5% FSO

"""Means in a row with no common superscripts are significantly different (P<05, n = 12). *PUFA = polyunsaturated fatty acids, AT = animal tallow, FSO = flaxseed oil. •Significantly different from Day 7 (P<05).

0, 1.5, and 4.5% FSO. After 3 wk of feeding, these values increased further to 8.8 and 17.5% ©3 fatty acids in muscles of birds fed 1.5 and 4.5% FSO, respectively. These levels of incorporation apparently do not reflect the maximum, because muscle contained 27% ©3 fatty acids when diets containing 5% FSO were fed to broiler chicks for 56 days (Phetteplace and Watkins, 1989). The longer chain co3 fatty acids (eicosapentaenoic acid, ^20:50)3! docosapentaenoic acid, Q&^Qg; and docosahexaenoic acid, C^oog) were also deposited in tissue lipids in proportion to the level of FSO fed. The observation that the ©3 fatty acid of the diet is incorporated into tissue lipids is consistent with other reports with

chicks (Phetteplace and Watkins, 1989) and with rats (Garg et al, 1988). The present results demonstrate that chicks are able to desaturate and elongate Cig^^ fatty acid from a plant source. However, it appeared from the current results that the ability of the chick to synthesize the long chain 0)3 fatty acid from Ci8:3o)3 was limited. For example, although amounts of Cig^^ in tissues increased up to 14-fold with FSO feeding, amounts of other ©3 fatty acids increased by only two- to fivefold. Thus, in spite of the increased availability of C i s ^ ^ to the chick, there was not a proportional increase in the deposition of C

2Q\5

C

22:5o>3. and C22 : 6 ( B 3.

Evidence was obtained from the present studies to show that dietary FSO reduced the

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Cl8:33 C22:53 Cl8:2co6 C 20:2co6 C20:3eo6 C 20:4a>6 c 22:4
Diet 1 6% AT 0% FSO

FLAXSEED OIL IN BROILER DIETS

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Association of Official Analytical Chemists., Washington, DC. and C22:5oo6 in the lipids of Sartorius muscles Atteh, J. O., S. Leeson, and R. J. Julian. 1983. Effects of after prolonged feeding. It has been suggested dietary levels and types of fat on performance and that this may be the result of an inhibition of mineral metabolism of broiler chicks. Poultry Sci 62:2403-2411. the desaturation of Q\%-2^>to Q20:4o)6> possibly through competition of C\%^isa with CI8:26 f r o m C18:2W6 (Brenner, 1974; Garg et studies of protein turnover. Comp. Biochem. Physiol. al, 1988). A number of investigators (Miller et 92A: 555-563. al, 1969; Hulan et al., 1988; Lee et al., 1988) Brenner, R. R., 1974. The oxidative desaturation of unsaturated fatty acids in animals. MoL Cell. have made similar observations with respect to Biochem. 3:41-52. ©3 fatty acids interfering with die synthesis of Cunnane, S. C , P. A. Stitt, S. Ganguli, and J. K. m C20:4oi6 ft° Ci8:2o)6- This interference may Armstrong, 1990. Raised 0)3 fatty acid levels in pigs partly account for the higher amounts of Cxg: fed flax. Can. J. Anim. Sci. 70:251-254. Folch, J., M. Lees, and G. H. Sloane Stanley, 1957. A 2(o6 fatty acid observed in birds fed FSO. simple method for isolation and purification of total The consumption of ©3 fatty acids has been lipids from animal tissues. J. Biol. Chem. 226: shown to influence the metabolism of fatty 497-509. acids (e.g., Garg et al, 1988) as well as die Garg, M L., E. Sebokova, A. Wierzbicki, A.B.R. synthesis of metabolites derived from fatty Thomson, and M. T. Oandinin, 1988. Differential acids, particularly prostaglandins and thromeffects of dietary linoleic and flinolenic acid on lipid metabolism in rat tissues. Lipids 23:847-852. boxanes (Lee et al, 1988). These changes may in turn alter diverse aspects of metabolism. For Hulan, H. W., R. G. Ackman, W.MJI. Ratnayake, and P. G. Proudfoot, 1988. co3 fatty acid levels and example, recent work (reviewed by Palmer, performance of broiler chickens fed redfish meal or 1990) suggests that prostaglandins may be redfish oil. Can. J. Anim. Sci. 68:533-547. important in the regulation of muscle protein Hulan, H. W., P. G. Proudfoot, and D. M. Nash, 1984. The metabolism and deposition. The effects of effects of different fat sources on general performance and carcass fatty acid composition. Poultry Sci. dietary co3 fatty acids in this context have not 63:324-332. been clarified. Klatt, L., 1986. The lure of omega-3-polyunsaturated fatty In conclusion, die muscles of broiler chickacids. Food Sci. Ncwsl. 16:1-4. ens are enriched with polyunsaturated fatty Lee, J. H., M. Sugano, and T. Ide, 1988. Effects of various combinations of a>3 and 0)6 polyunsaturated fats with acids, particularly co3 fatty acids, when fed saturated fats on serum lipid levels and eicosanoid diets containing FSO. The results demonproduction in rats. J. Nutr. Sci. Vitaminol. 34: strated that poultry meat products may be 117-129. substantially altered in their fat composition by Miller, D., K. C. Leong, and P. Smith, Jr., 1969. Effect of feeding specific mixtures of fatty acids. The feeding and withdrawal of menhaden oil on the a& present studies also provided an insight into and 0)6 fatty acid content of broiler tissues. J. Food Sci. 34:136-141. fatty acid metabolism of chicks as influenced Morrison, W. R., and M. L. Smith, 1964. Preparation of by 6. 022:40)6'

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