Poult. Sci.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Poult Sci 2007. 86:318-324
© 2007 Poultry Science Association
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via ISI Web of Science (1)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Suksombat, W.
Right arrow Articles by Lounglawan, P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Suksombat, W.
Right arrow Articles by Lounglawan, P.

METABOLISM AND NUTRITION

Effects of Various Levels of Conjugated Linoleic Acid Supplementation on Fatty Acid Content and Carcass Composition of Broilers

W. Suksombat1, T. Boonmee and P. Lounglawan

School of Animal Production Technology, Institute of Agricultural Technology, Suranaree University of Technology, Muang, Nakhon Ratchasima, 30000, Thailand

1 Corresponding author: wisitpor{at}sut.ac.th


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 REFERENCES
 
The effects of dietary conjugated linoleic acid (CLA) supplementation on growth performance, carcass quality, free fatty acid composition, and accumulation of CLA were investigated in broilers. Four hundred eighty 3-wk-old broilers were assigned to 4 dietary treatments (0, 0.5, 1.0, and 1.5% CLA) with 6 replicates of 20 chickens. Feed consumption and BW were recorded at every 5-d period. On d 42, carcass compositions were determined from 30 birds per treatment. There were no significant differences in average daily feed intake among the treatments. However, feed conversion ratio was highly significantly different (P < 0.01) between treatments, and average daily gain was significantly reduced by a supplement of dietary CLA (P < 0.05). Live weight and percentages of carcass, drumstick, thigh, boneless thigh, pectoralis major, and pectoralis minor were not influenced by the dietary CLA. Abdominal fat was significantly reduced (P < 0.01) with the increased CLA level in the broilers’ diets. Percentages of liver weight were significantly increased (P < 0.01) after the CLA treatments. Percentages of drumstick and boneless drumstick were significantly decreased (P < 0.05) by dietary CLA. In terms of free fatty acid composition in broiler meat, CLA addition significantly increased (P < 0.05) saturated fatty acids, especially in thigh muscle, whereas unsaturated fatty acids were unchanged. Accumulations of CLA in meat were significantly increased (P < 0.05) with increasing CLA level in the diet.

Key Words: conjugated linoleic acid • growth performance • fatty acid composition • broiler


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 REFERENCES
 
Conjugated linoleic acid (CLA) consists of a group of geometric and positional isomers of linoleic acid. Conjugated linoleic acid is used as a collective term because all known isomers have double bonds with a single carbon bond in between instead of the usual methylene-separation. The predominant CLA isomer is rumenic acid (cis9, trans11 octadecadienoic acid), which represents 90% of CLA present in milk and 75% of CLA present in beef fat (Chin et al., 1992). Ruminant products show relatively high concentrations of CLA (0.5 to 1.5% of total fatty acids), whereas meats from monogastric animals are poor sources of these compounds (0.1 to 0.2% of total fatty acids). Fish and some vegetables also contain low CLA concentrations (Chin et al., 1992).

Interest in CLA has increased in the past 2 decades as a result of its potential beneficial health effects. Conjugated linoleic acid was found to act as a growth factor (Chin et al., 1994) and a fat-to-lean repartitioning agent (Pariza et al., 1996; Park et al., 1997; Ostrowska et al., 1999) and to show anticarcinogenic (Schulz et al., 1992; Ip, 1997), hypocholesterolemic, and antiatherogenic (Lee et al., 1994; Nicolosi et al., 1997) properties. Conjugated linoleic acid was also involved in stimulating the immune functions in chickens and rats (Cook et al., 1993; Wong et al., 1998; Hayek et al., 1999). In humans, milk fat consumption as the major source of CLA (Jiang et al., 1999) was demonstrated to protect against the risk of breast cancer in women (Knekt et al., 1996).

In view of the above health-related effects of CLA it seems desirable to provide CLA-enriched products for human consumption. It has already been demonstrated that CLA is readily incorporated in tissue lipids in broilers (Szymczyk et al., 2001), pigs (Dugan et al., 1997; Dunshea et al., 1998; Ostrowska et al., 1999; Thiel-Cooper et al., 2001), and egg yolk (Raes et al., 2002). The purpose of this study was to determine the effect of dietary CLA supplementation on growth performance, feed conversion efficiency, carcass composition, and fatty acid composition in broiler chickens.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS AND DISCUSSION
 REFERENCES
 
Experimental Animals
All experiments were conducted in accordance with the principles and guidelines approved by the Suranaree University of Technology Animal Care and Use committee, which followed Guidelines for the Care and Use of Agricultural Animals in Agricultural Research and Teaching (FASS, 1999). Four hundred eighty broilers (Arbor Acres; 3 wk old) were randomly assigned to 4 groups. Each group (120 broiler chickens) was further randomly divided into 6 replicates of 20 chickens. Chickens were kept under conditions of evaporative cooling system and lighting program (16L:8D) throughout the entire experiments. Chickens were fed diets and water ad libitum during the entire experimental period.

Experimental Diets
Each group of chickens was randomly fed an experimental diet, containing 0, 0.5, 1.0, and 1.5% CLA. All experimental diets were isonitrogenous and isocaloric and formulated to meet the National Research Council (1994) requirements. Chickens were fed experimental diets containing 3,267 kcal of ME/kg, 20.1% crude protein, 1.11% lysine, 0.72% methionine + cystine, 0.99% calcium, and 0.60% phosphorus. Chemical analysis of the diets was made for crude protein, crude fiber, ether extract, and ash (AOAC, 1998). Feed ingredients and chemical compositions of the experimental diets are presented in Table 1Go. Chickens were given the 4 dietary treatments that consisted of 4 graded levels (0.0, 0.83, 1.67, and 2.5%) of the commercial liquid CLA [BASF (Thai) Ltd., Bangkok, Thailand] containing 60% CLA (30% c9, t11; 30% t10, c12), 22% oleic acid, 6% palmitic acid, 4% stearic acid, 2% linoleic acid, and 6% other isomers of fatty acids. Thus, the resulting dietary CLA concentrations were 0.0, 0.5, 1.0, and 1.5%, respectively.


View this table:
[in this window]
[in a new window]

  		Table 1. Ingredient and calculated nutrient composition of basal diets (as-fed basis)
 
Growth Performance and Carcass Quality
Feed consumption and body weight were recorded at every 5-d period. On d 42, 30 birds per each treatment were stunned and slaughtered by neck cutting and exsanguinated. Carcasses were then plucked and eviscerated to determine carcass weight as a percentage of live weight, and abdominal fat (considered to be the fat extending within the ischium, surrounding the cloaca, and adjacent to the abdominal muscle) and pectoralis major, thigh, and drumstick muscle weight as a percentage of carcass weight. Samples of pectoralis major, thigh, and drumstick muscles were stored frozen (–20°C) for further analysis.

Fatty Acid Analysis
Fatty acid analysis was determined as previously described by Raes et al. (2000, 2001). In brief, lipids were extracted from fresh meat using chloroform/methanol (2:1, vol/vol, modified from Folch et al., 1957). Nonadecanoic acid (19:0) was added as an internal standard. The fatty acid methyl esters (FAME) were analyzed by gas chromatography using a CP-Sil88 column (model 6890, Hewlett Packard, Santa Clara, CA) for FAME (100 m x 0.25 mm). The gas chromatography conditions were as follows: injected temperature, 240°C; detector temperature, 260°C; carrier gas, He; split ratio, 1/30; temperature program, 70°C for 4 min, followed by an increase of 13°C/min to 175°C, then 4°C/min to 215°C. Peaks were identified by comparison of retention times with those of the corresponding standards (Supelco 37 component FAME Mix, Sigma-Aldrich Co., St. Louis, MO). Identification of the peak included fatty acids between 14:0 and 22:6 and the following CLA isomers: c9, t11; t10, and c12.

Statistical Analysis
The observed effects between treatment groups were statistically analyzed by ANOVA in a completely randomized design (Steel and Torrie, 1986), and significant differences between means were compared by Duncan’s New Multiple Range Test according to the methods previously described by SAS (1994). The effects of increasing CLA were partitioned into linear components using orthogonal polynomial contrasts (SAS Institute, 1994).


   RESULTS AND DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
REFERENCES
 
Broiler Performance and Carcass Quality
Ingredient and calculated nutrient composition of finisher diets are presented in Table 1Go. The calculated nutrient composition is based on NRC recommendation (NRC, 1994). Fat content among the diets was similar. The content of palmitic, stearic, linoleic, linolenic, arachidonic, and docosahexaenoic acids in diets decreased as the amount of CLA increased and amount of soybean oil decreased (Table 2Go). In contrast, palmitoleic and oleic acids, cis9, trans11; trans10, cis12, and total CLA increased with increasing CLA level and reducing soybean oil level in the diets. As a result, saturated fatty acids (SFA) and polyunsaturated fatty acids (PUFA) decreased, whereas monounsaturated fatty acids (MUFA) increased. These results are similar to other studies of supplemented CLA in broiler diets (Szymczyk et al., 2001; Aletor et al., 2003; Sirri et al., 2003).


View this table:
[in this window]
[in a new window]

  		Table 2. Fatty acid composition (g/100 g of fatty acid) of feeds used in the experiment1
 
Feeding CLA at levels of 0.5 to 1.0% in the diet improved feed efficiency, growth, meat production, or a combination of these in rats, mice, and pigs (Chin et al., 1994; Dugan et al., 1997; West et al., 1998; Ostrowska et al., 1999). In contrast to mammals, Szymczyk et al. (2001) observed marked reduction of weight gain and feed conversion relative to control chickens when broiler chickens were fed on diets containing 0.0 to 1.5% CLA. In the present study, average daily gain (g/bird) was significantly and linearly (P < 0.05) decreased by dietary CLA, whereas no effects of CLA on average daily feed intake (g/bird) were noted (Table 3Go). Feed conversion ratio increased with increasing CLA. Depressed growth performance in broilers, resulting from feeding diets containing 0.0, 0.5, 1.0 and 1.5% dietary CLA, was consistent with earlier findings (Szymczyk et al., 2001). Previously, Du and Ahn (2002) showed that dietary CLA at levels of 2.0 and 3.0% in the diets for 5 wk reduced whole fat content without significant reduction in body weight gain, but feeding 1.0% CLA for 3 wk did not affect growth or abdominal and whole fat content in broiler chickens. This suggests that dietary CLA is less effective in changing body composition in chickens. Pariza et al. (2001) noted that the cis9, trans11 CLA isomer that enhances growth and probably feed efficiency in young rodents, and the trans10, cis12 CLA isomer that changes body composition use separate biochemical mechanisms. Therefore, feeding periods, dietary concentration, and type of isomer of CLA may be factors affecting growth performance and body fat content.


View this table:
[in this window]
[in a new window]

  		Table 3. Effect of conjugated linoleic acid (CLA) supplementation on growth performance and carcass composition1
 
No effects of CLA on BW, carcass percentage, and percentages of thigh, boneless thigh, pectoralis major, and pectoralis minor were observed. However, percentages of liver and boneless drumstick were significantly different. Of interest was the significant and linear reduction in the percentage of abdominal fat with increasing CLA in the diets. Dietary CLA was reported as a potent inhibitor of body fat accumulation in mice, rats, and chicken (Pariza et al., 1996). At relatively high dietary CLA concentrations (exceeding 1.0%), the beneficial changes in body composition did not bring expected improvements in growth performance. The possible explanation is that an excessive CLA treatment may stimulate fatty acid oxidation and thus enhance metabolic rate in animals, as demonstrated in mice (West et al., 1998). The changes in broiler carcass composition were comparable, at least in part, with similar alterations reported earlier in pigs fed CLA-supplemented diets. Significantly reduced deposition of abdominal fat in broilers was in line with fat to lean repartition, reduced back fat thickness, and lower fat contents of commercial meat cuts in pigs fed CLA (Dugan et al., 1997; Dunshea et al., 1998; Thiel-Cooper et al., 2001).

The effects of dietary CLA on moisture, CP, and fat contents in thigh drumstick and pectoralis major meats are presented in Table 4Go. Moisture and CP contents of carcass were similar in all treatments. However, fat content of drumstick meat was significantly reduced with increasing CLA supplementation, whereas those of thigh and pectoralis major meats were similar.


View this table:
[in this window]
[in a new window]

  		Table 4. Effect of conjugated linoleic acid (CLA) supplementation on chemical composition of various meats
 
Fatty Acid Content of Broiler Meat
The effect of CLA supplementation on fatty acid composition of thigh, drumstick, and pectoralis major meats is given in Tables 5Go, 6Go, and 7Go. As could be expected, feeding incremental levels of dietary CLA (0.0 to 1.5%) resulted in linear increases in concentrations of CLA isomers in tissue lipids. Indeed, dietary CLA isomers were efficiently transferred in mice (Belury and Kempa-Steczko, 1997), rats (Chin et al., 1994; Sugano et al., 1997; Szymczyk et al., 2000), and pigs (Kramer et al., 1998) to various classes of body lipids. Szymczyk et al. (2001) found that incorporation of individual CLA isomers into body lipids differed as indicated by preferential incorporation of cis9, trans11 CLA at the expense of trans10, cis12 and other isomers. The findings of the present study are comparable with the previous study, which found that cis9, trans11 CLA isomer accounted for 54 to 56% of the total CLA in muscle lipids (Szymczyk et al., 2001). The concentration of individual CLA isomers in muscle lipid does not completely reflect those in diet. As shown in Table 2Go, the percentage of cis9, trans11 and trans10, cis12 in the CLA source were 30 and 30%, respectively; however, their percentages in muscle lipids differed appreciably at 60 to 75% and 25 to 40%, respectively. However, the reason for the cis9, trans11 isomer being deposited at a higher level in muscle lipids is poorly understood, although it may be connected with the fact that some isomers are more effectively mobilized compared with others (Park et al., 1999). Szymczyk et al. (2001) reported that deposition rate of the cis9, trans11 isomer in muscle lipids was higher than that of the trans10, cis12 isomer.


View this table:
[in this window]
[in a new window]

  		Table 5. Effect of conjugated linoleic acid (CLA) supplementation on fatty acid composition of thigh
 

View this table:
[in this window]
[in a new window]

  		Table 6. Effect of conjugated linoleic acid (CLA) supplementation on fatty acid composition of drumstick1
 

View this table:
[in this window]
[in a new window]

  		Table 7. Effect of conjugated linoleic acid (CLA) supplementation on fatty acid composition of breast1
 
Supplementing the grower diet of broilers (Cobb 500) from d 22 to slaughtering at d 47 with 2.0 or 4.0% CLA resulted in higher CLA concentrations in pectoralis major and drumstick tissues compared with the control group (Sirri et al., 2003). Similar results were reported by Aletor et al. (2003) in Ross broilers. Previously, Szymczyk et al. (2001) investigated the effects of increasing CLA concentrations (0.0, 0.5, 1.0, and 1.5%) in starter and grower diet from d 4 to 42 in Arbor Acres chickens and found a linear increase of CLA in tissue samples associated with CLA supplementation and no CLA in the control group. Supplementing the diet of 3-wk-old broiler chickens with 0.0, 2.0, and 3.0% CLA over a 5-wk period resulted in 0, 105, and 178 mg of CLA/g of lipids in pectoralis major muscle, respectively (Du and Ahn, 2002).

Apart from increased CLA contents in the adipose and muscle tissue, the supplementation of CLA also influences tissue fatty acid composition in pigs. Several reports indicated that CLA supplementation increased the amount of SFA (C14:0, C16:0, and C18:0) and decreased the MUFA fraction in pig tissues by downregulating the 9-desaturase activity (O’Quinn et al., 2000; Bee, 2001; Eggert et al., 2001; Ramsay et al., 2001; Thiel-Cooper et al., 2001; Joo et al., 2002; Wiegand et al., 2002; Lauridsen et al., 2005). A higher saturation ratio is less desirable from the human health perspective. The same changes in fatty acid composition were seen in broilers when CLA was supplemented (Szymczyk et al., 2001; Du and Ahn, 2002; Aletor et al., 2003; Sirri et al., 2003).

Szymczyk et al. (2001) reported the striking results that they found the changes in the relative proportions of different classes of fatty acids in the abdominal fat, pectoralis major, and leg muscles. Generally, the SFA content was significantly increased and that of the MUFA and PUFA decreased. The changes in the fatty acid profiles were due mainly to increases in concentrations of C16:0 and C18:0 and concurrent opposite changes in concentrations of C16:1, C18:1, C18:2, and C20:4. The findings of the present study are comparable with the study of Szymczyk et al. (2001), which found that the SFA content in muscle lipids tended to increase and the MUFA and PUFA contents tended to decrease. These could have resulted from the inhibition of {Delta}9-desaturase activity in the liver, caused by CLA.

In conclusion, the present study shows that feeding CLA in incremental dietary concentrations to broilers is an effective method to obtain CLA-enriched meat and thus the potential health-related benefits of CLA consumption in humans. At the same time, the deposition of abdominal fat is favorably reduced, and the relative proportion of thigh, pectoralis major, and drumstick muscles (% of carcass weight) is unaffected. The CLA supplementation tends to adversely affect the fatty acid composition of these tissues by increasing SFA content at the expense of MUFA and PUFA. Further studies are required to investigate the optimum concentration and balance of CLA isomers needed to obtain CLA-enriched broiler meat.


   ACKNOWLEDGMENTS
 
Authors would like to express special thanks to University’s Poultry Farm, the Center for Scientific and Technological Equipment for their great support. Financial support was provided by the Institute of Research and Development, Suranaree University of Technology. The CLA products were provided by BASF (Thai) Ltd. (Thailand).

Received for publication June 25, 2006. Accepted for publication November 6, 2006.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 REFERENCES
 
Aletor, V. A., K. Eder, K. Becker, B. R. Paulicks, F. X. Roth, and D. A. Roth-Maier. 2003. The effects of conjugated linoleic acids or an alpha-glucosidase inhibitor on tissue lipid concentrations and fatty acid composition of broiler chicks fed a low-protein diet. Poult. Sci. 82:796–804.[Abstract/Free Full Text]

Association of Official Analytical Chemists. 1998. Official Methods of Analysis. 16th ed. Assoc. Off. Anal. Chem., Washington, DC.

Bee, G. 2001. Dietary conjugated linoleic acids affect tissue lipid composition but not de novo lipogenesis in finishing pigs. Anim. Res. 50:383–399.

Belury, M. A., and A. Kempa-Steczko. 1997. Conjugated linoleic acid modulates hepatic lipid composition in mice. Lipids 32:199–204.[Medline]

Chin, S. F., W. Eiu, J. M. Storkson, Y. E. Ha, and M. W. Pariza. 1992. Dietary sources of conjugated dienoic isomers of linoleic acid. A newly recognized class of anticarcinogens. J. Food Comp. Anal. 5:185–197.

Chin, S. F., J. M. Storkson, K. J. Albright, M. E. Cook, and M. W. Pariza. 1994. Conjugated linoleic acid is a growth factor for rats as shown by enhanced weight gain and improved feed efficiency. J. Nutr. 124:2344–2349.[Abstract/Free Full Text]

Cook, M. E., C. C. Miller, Y. Park, and M. W. Pariza. 1993. Immune modulation by altered nutrient metabolism: Nutritional control of immune-induced growth depression. Poult. Sci. 72:1301–1305.[ISI][Medline]

Du, M., and D. U. Ahn. 2002. Effect of dietary conjugated linoleic acid on the growth rate of live birds and on the abdominal fat content and quality of broiler meat. Poult. Sci. 81:428–433.[Abstract/Free Full Text]

Dugan, M. E. R., J. L. Aalhus, A. L. Schaefer, and K. G. Kramer. 1997. The effect of conjugated linoleic acid on fat to lean repartitioning and feed conversion in pigs. Can. J. Anim. Sci. 77:723–725.

Dunshea, F. R. E., M. Ostrowska, R. Muralitharan, R. Cross, D. E. Bauman, M. W. Pariza, and C. Skarie. 1998. Dietary conjugated linoleic acid decreases back fat in finisher gilts. J. Anim. Sci. 77:158.

Eggert, J. M., M. A. Belury, A. Kempa-Steczko, S. E. Millis, and A. P. Schinckel. 2001. Effects of conjugated linoleic acid on the belly firmness and fatty acid composition of genetically lean pigs. J. Anim. Sci. 79:2866–2872.[Abstract/Free Full Text]

FASS. 1999. Guidelines for the Care and Use of Agricultural Animals in Agricultural Research and Teaching. 1st rev. ed. Fed. Anim. Sci. Soc., Savoy, IL.

Folch, J., M. Less, and G. M. Sloane-Stanley. 1957. A simple method for the isolation and purification of total lipids from animal tissues. J. Biol. Chem. 226:497–509.[Free Full Text]

Hayek, M. G., S. N. Han, D. Wu, B. A. Watkins, M. Meydani, J. L. Dorsey, D. E. Smith, and S. N. Meydani. 1999. Dietary conjugated linoleic acid influences the immune response of young and old C57BL/6NCrlBR mice. J. Nutr. 129:32–38.[Abstract/Free Full Text]

Ip, C. 1997. Review of the effects of trans fatty acids, oleic acid, n-3 polyunsaturated fatty acids, and conjugated linoleic acid on mammary carcinogenesis in animals. Am. J. Clin. Nutr. 66:1523S–1529S.[Abstract/Free Full Text]

Jiang, J., A. Wolk, and B. Vessby. 1999. Relation between the intake of milk fat and the occurrence of conjugated linoleic acid in human adipose tissue. Am. J. Clin. Nutr. 70:21–27.[Abstract/Free Full Text]

Joo, S. T., J. I. Lee, Y. L. Ha, and G. B. Park. 2002. Effects of dietary conjugated linoleic acid on fatty acid composition, lipid oxidation, color, and water holding capacity of pork loin. J. Anim. Sci. 80:108–112.[Abstract/Free Full Text]

Knekt, P., R. Jarvinen, R. Seppanen, E. Pukkala, and A. Aroma. 1996. Intake of dairy products and the risk of breast cancer. Br. J. Cancer 73:687–691.[ISI][Medline]

Kramer, J. K., N. Sehat, M. E. Dugan, M. M. Mossagba, J. M. P. Urawecz, J. A. Roach, K. Eulitz, J. L. Aalhus, A. L. Schaefer, and Y. Ku. 1998. Distribution of conjugated linoleic (CLA) isomers in tissue lipid classes of pigs fed a commercial CLA mixture determined by gas chromatography and silver ion-high-performance liquid chromatography. Lipids 33:549–558.[ISI][Medline]

Lauridsen, D., H. Mu, and P. Henckel. 2005. Influence of dietary conjugated linoleic acid (CLA) and age at slaughtering on performance, slaughter- and meat quality, lipoproteins, and tissue deposition of CLA in barrows. Meat Sci. 69:393–399.

Lee, K. N., D. Kritchevsky, and M. W. Pariza. 1994. Conjugated linoleic acid and atherosclerosis in rabbits. Atherosclerosis 108:19–25.[ISI][Medline]

National Research Council. 1994. Nutrient Requirements of Poultry. 9th rev. ed. Natl. Acad. Press. Washington, DC.

Nicolosi, R. J., E. J. Rogers, D. Kritchevsky, J. A. Scimeca, and P. J. Huth. 1997. Dietary conjugated linoleic acid reduces plasma lipoproteins and early aortic atherosclerosis in hyper-cholesterolemic hamsters. Artery 22:266–277.[ISI][Medline]

O’Quinn, P. R., J. L. Nelssen, R. D. Goodband, J. A. Unruh, J. C. Woodworth, J. S. Smith, and M. D. Tokach. 2000. Effects of modified tall oil versus a commercial source of conjugated linoleic acid and increasing levels of modified tall oil on growth performance and carcass characteristics of growing-finishing pigs. J. Anim. Sci. 78:2359–2368.[Abstract/Free Full Text]

Ostrowska, E., M. Muralitharan, R. F. Cross, D. E. Bauman, and F. R. Dunshea. 1999. Dietary conjugated linoleic acids increase lean tissue and decrease fat deposition in growing pigs. J. Nutr. 129:2037–2042.[Abstract/Free Full Text]

Pariza, M. W., Y. Park, and M. E. Cook. 2001. The biologically active isomers of conjugated linoleic acid. Prog. Lipid Res. 40:283–298.[ISI][Medline]

Pariza, M. W., Y. Park, M. E. Cook, K. J. Albright, and W. Liu. 1996. Conjugated linoleic acid (CLA) reduces body fat. FASEB J. 10:A560.

Park, Y., K. J. Albright, W. Liu, J. M. Storkson, M. E. Cook, and M. W. Pariza. 1997. Effect of conjugated linoleic acid on body composition in mice. Lipids 32:853–858.[ISI][Medline]

Park, Y., K. J. Albright, J. M. Storkson, W. Liu, M. E. Cook, and M. W. Pariza. 1999. Changes in body composition during feeding and withdrawal of dietary conjugated linolenic acid. Lipids 34:243–248.[ISI][Medline]

Raes, K., S. De Smet, and D. Demeyer. 2000. Conjugated linoleic acid and poly-unsaturated fatty acids in intramuscular fat of Belgian Blue bulls: Effect of double-muscling. Pages 68–69 in Proc. 46th ICoMST, Buenos Aires, Argentina.

Raes, K., S. De Smet, and D. Demeyer. 2001. Effect of double-muscling in Belgian Blue young bulls on the intramuscular fatty acid composition with emphasis on conjugated linoleic acid and poly-unsaturated fatty acids. Anim. Sci. 73:253–260.

Raes, K., G. Huyghebaert, S. De Smet, L. Nollet, S. Amouts, and D. Demeyer. 2002. The deposition of conjugated linoleic acid in eggs of laying hens fed diets varying in fat level and fatty acid profile. J. Nutr. 132:182–189.[Abstract/Free Full Text]

Ramsay, T. G., C. M. Evock-Clover, N. C. Steele, and M. J. Azain. 2001. Dietary conjugated linoleic acid alters fatty acid composition of pig skeletal muscle and fat. J. Anim. Sci. 79:2152–2161.[Abstract/Free Full Text]

SAS Institute. 1994. SAS/STAT User’s Guide. Version 6.12 Edition. SAS Institute Inc., Cary, NC.

Schulz, T. D., B. P. Chew, W. R. Seaman, and L. O. Luedecke. 1992. Inhibitory effect of conjugated dienoic derivatives of linoleic acid and beta-carotene on the in vitro growth of human cancer cells. Cancer Lett. 63:125–133.[ISI][Medline]

Sirri, F., N. Tallarico, A. Meluzzi, and A. Franchini. 2003. Fatty acid composition and productive traits of broiler fed diets containing conjugated linoleic acid. Poult. Sci. 82:1356–1361.[Abstract/Free Full Text]

Steel, R. G. D., and J. H. Torrie. 1986. Principles and Procedures of Statistics: A Biometric Approach, 5th ed. McGraw Hill International Book Company, New York, NY.

Sugano, M., A. Tsujita, M. Yamazaki, K. Yamada, I. Ikeda, and D. Kritchevsky. 1997. Lymphatic recovery, tissue distribution, and metabolic effects of conjugated linoleic acid in rats. J. Nutr. Biochem. 8:38–43.[ISI]

Szymczyk, B., P. Pisulewski, W. Szczurek, and P. Hanczakowski. 2001. Effects of conjugated linolenic acid on growth performance, feed conversion efficiency, and subsequent carcass quality in broiler chickens. Br. J. Nutr. 85:465–473.[ISI][Medline]

Szymczyk, B., P. M. Pisulewski, P. Hanczakowski, and W. Szczurek. 2000. The effects of feeding conjugated linoleic acid on rat growth performance, serum lipoproteins and subsequent lipid composition of selected rat tissues. J. Sci. Food Agric. 80:1553–1558.[ISI]

Thiel-Cooper, R. L., F. C. Parrich, J. C. Sparks, B. R. Wiegand, and R. C. Ewan. 2001. Conjugated linoleic acid changes swine performance and carcass composition. J. Anim. Sci. 79:1821–1828.[Abstract/Free Full Text]

West, D. B., J. P. Delany, P. M. Camet, F. Blohm, A. A. Truett, and J. Scimeca. 1998. Effects of conjugated linoleic acid on body fat and energy metabolism in the mouse. Am. J. Physiol. 44:R667–R672.

Wiegand, B. R., J. C. Sparks, F. C. Jr. Parrish, and D. R. Zimmerman. 2002. Duration of feeding conjugated linoleic acid influences growth performance, carcass traits, and meat quality of finishing barrows. J. Anim. Sci. 80:637–643.[Abstract/Free Full Text]

Wong, M. W., B. P. Chew, T. S. Wong, H. L. Hosick, T. D. Boylston, and T. D. Schulz. 1998. Effects of dietary conjugated linoleic acid on lymphocyte function and growth of mammary tumors in mice. Anticancer Res. 17:987–993.





This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via ISI Web of Science (1)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Suksombat, W.
Right arrow Articles by Lounglawan, P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Suksombat, W.
Right arrow Articles by Lounglawan, P.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS