Journal Search Engine
Search Advanced Search Adode Reader(link)
Download PDF Export Citaion korean bibliography PMC previewer
ISSN : 1598-5504(Print)
ISSN : 2383-8272(Online)
Journal of Agriculture & Life Science Vol.50 No.5 pp.129-137
DOI : https://doi.org/10.14397/jals.2016.50.5.129

Effects of Dietary Lysine and Gamma-linolenic Acid Levels on Growth Performance and Meat Quality in Finishing Pigs

Sung Dae Lee1*, Hyun Jung Jung1,2, Jun Cheol Park3, Young Min Song4
1Animal Nutrition & Physiology Team, National Institute of Animal Science, RDA, Wanju, 55365, Korea
2International Technology Cooperation Center, Technical Cooperation Bureau, RDA, Jeonju, 54875, Korea
3Swine Science Division, National Institute of Animal Science, RDA, Cheonan, 31000, Korea
4Department of Animal Material Engineering, Gyeongnam National University of Science & Technology, Jinju, 52725, Korea
Corresponding author: Sung Dae Lee +82-63-238-7454+82-63-238-7494leesd@korea.kr
May 17, 2016 June 28, 2016 July 28, 2016

Abstract

This study investigated the effect of dietary lysine and gamma-linolenic acid(GLA) levels on growth performance, carcass traits, and meat quality in finishing pigs. Pigs were provided with feed containing two different levels of lysine(0.45% and 0.75%) with three different levels of gamma-linolenic acid(0.0, 0.3, and 0.6%). Average daily gain(ADG) was significantly lower (p<0.01) in pigs provided with the lower level of lysine. In contrast, feed/gain(p<0.01), diet cost/gain(p<0.05), and intramuscular fat(p<0.01) were all significantly higher in pigs fed the lower level of lysine. Similarly, meat color scores(CIE L*, a*, and b*) and cooking loss were significantly higher(p<0.01) in pigs fed the lower level of lysine, whereas shear force(kg/2.5 inch2)was not affected by dietary lysine. The addition of GLA had no significant effect on any of the parameters measured. The results indicate that providing pigs with 0.45% lysine in their diet may help to increase intramuscular fat content, allowing the industry to produce pork products that meet consumer needs in Korea.


초록


    Introduction

    With a growing interest in maintaining better health, consumers are increasingly avoiding high-fat products. Consequently, the pork industry is developing methods to produce low-fat pork products, e.g., by producing lean breeding pigs. However, the decline of intramuscular fat content has also resulted in an improvement in the juiciness and tenderness of pork(Hodgson et al., 1991; Castell et al., 1994), which may have a positive effect on consumers’ preference for pork products.

    The intramuscular fat content of pork is highly dependent on the meat quality traits of the breeding pig. Previous research has shown that low protein or low lysine diets can help to increase the intramuscular fat content(Essén-Gustavsson et al., 1994; Witte et al., 2000; Donato et al., 2006). Once absorbed, lysine is synthesized into carnitine by the liver and pancreas. This is then accumulates in the muscle(Mayes, 1996), where it promotes the breakdown of fatty acids. Thus, low levels of carnitine may result in reduced breakdown of fatty acids, increasing accumulated fat content in muscles(Heo et al., 2000). Low levels of carnitine also reduce protein and lysine content, resulting in a decrease in the protein synthesis rate in muscles, and allowing redundant amino acids to break up and be synthesized into body fat(Witte et al., 2000).

    A number of studies have investigated to increase the functionality of pork products, with the particular fatty acids. Gamma-linolenic acid(GLA) is being heralded as the next-generation functional fatty acid, as a number of studies have shown that it helps to reduce blood cholesterol levels and stimulate metabolism(Zurier et al., 1996; Johnson et al., 1997; Kang & Park, 2007). Gamma fatty acids such as GLA are intermediary substances in the metabolic conversion of linoleic acid(Horrobin, 1992; Sayanova, 1998).

    By increasing the fat content of pork, its juiciness and flavor may also be enriched. However, this may have a negative effect on consumer’s health. Thus, there is a need to develop a functional fatty acid. There are limited studies which has investigated the combination effects of dietary lysine and GLA on intramuscular fat content in pigs.

    Therefore, this study investigated the effect of lysine and GLA on the growth performance, carcass traits, and meat quality in finishing pigs.

    Materials and methods

    1.Animals and diets

    Sixty hybrid pigs(Landrance x Large White x Duroc; 76.4 ± 1.0 kg body weight, approximately 135 days of age) were used in this study. Pigs were randomly allocated to 30 pens(3.2 m x 1.5 m with solid plastic flooring), with two pigs per pen and five replicate pens per treatment. Animals were not separated by sex(gilt and barrow), but the ratio of sexes was similar in each allotment.

    The pigs had access to water and feed ad libitum for 52 days. The ingredients and chemical compositions of the diets used in this experiment are shown in Table 1. The experiment tested the effect of two levels of lysine(0.45%, 0.75%) with three levels of GLA(0.0%, 0.3%, 0.6%) on growth performance, carcass traits, and meat quality, using a 2 x 3 factorial design. A 40% GLA powder extracted from evening primrose oil(Nuno B&T Cor., Dongducheon, Korea) was used. All nutrients, with the exception of lysine, met or exceeded the requirements of the National Research Council for finishing pigs(NRC, 1998), and the animal care was in accordance with the Guide for the Care and Use of Laboratory Animals(National Institute of Animal Science Animal Care Committee).

    The live weight of pigs and feed consumption were measured weekly to calculate average daily gain(ADG, kg/day), average daily feed intake(ADFI, kg/day), and the ratio of feed to gain(feed/gain). Diet cost/gain(won/kg) was calculated from the total feed cost and total gain.

    2.Slaughtering

    Following the 52 day experimental period, all pigs were transported to a standard abattoir near the experimental station. Following 12 h of feed restriction, the pigs were stunned electrically(300 V for 3 s) with a pair of stunning tongs, shackled by the right leg, and exsanguinated while hanging. Carcasses were then placed in a dehairer at 62°C for 5 min, following which any hair that remained was removed using a knife and flame. Carcasses were then eviscerated and split before being placed in a chiller set at 4°C for 24 h.

    3.Carcass traits

    Dressing percentage was calculated as the ratio of cold carcass weight to live weight after fasting, and backfat thickness was measured at the 10th rib (three-quarters of the distance along the longissimus dorsi muscle toward the belly). Marbling score and carcass grade were estimated by a pork carcass grading specialist from the Korea Institute for Animal Products Quality Evaluation(KAPE, 2011).

    4.Meat quality

    To determine the chemical compositions and physical parameters of meat, the longissimus dorsi muscle(6th to 13th rib) was cut off, stored at 4°C, and transported to the laboratory. The moisture, crude protein, intramuscular fat, and crude ash content of samples were measured approximately 24 h after slaughter, using the methods reported by AOAC(1995).

    Meat color of longissimus dorsi muscle was evaluated on the freshly cut surface of a 3 cm thick slice that had been placed in a 4°C cold room for 30 min, using a Minolta Chroma Meter CR-300(Minolta, Osaka, Japan). The average of three replicates was expressed using the CIE L*, a*, and b* color scale(CIE L = black (0) to white (100); CIE a = red (+) to green (-); CIE b = yellow (+) to blue (-)). Cooking loss was determined by calculating the percentage weight loss of a 150 g meat sample during 40 min cooking in an 80°C water bath. To determine shear force, samples were cooked individually in plastic bags immersed in a 75°C water bath for 30 min. The cooked meat was then cooled and sampled at room temperature using a 12.7 mm circular core to determine shear force. Four sample cores were sheared from each sample across the length of the core using a texture analyzer (TA-XT2i, Stable Micro Systems Ltd, Surrey, UK) fitted with a Warner-Bratzler shear attachment(V-type blade set), with a cross head speed of 2 mm/s. The shear force value was calculated as the mean of the maximum forces(kg) required to shear each set of core samples.

    5.Statistical analyses

    Statistical analyses were performed using the GLM procedure of the Statistical Analysis Systems Institute software package(SAS, 1995). The model included lysine level(L), GLAlevel(G) and the LxG interaction. The results are provided as means with a pooled standard error(SE).

    Results

    1.Growth performance

    The effects of dietary lysine and GLA levels on growth performance are presented in Table 2. The final weight(kg) and ADG(kg/day) were significantly lower (P<0.01) in pigs provided with the lower level of lysine, whereas lysine level had no significant effect onADFI(kg/day). In contrast, feed/gain(p<0.01) and diet cost/gain(won/kg, p<0.05) were significantly higher in pigs fed the lower level of lysine. The addition of GLA did not have a significant effect on any of the growth performance.

    2.Carcass traits

    The effects of dietary lysine and GLA levelson carcass traitsare shown in Table 3. Carcass weight (kg) was significantly lower(p<0.05) in pigs provided with the lowerlevel of lysine, whereas dressing percentage(%), backfat thickness(mm), marbling score, and carcass grade were not affected by lysine level. The addition of GLA did not have a significant effect on any of the carcass traits.

    3.Meat quality

    The effects of dietary lysine and GLA levels on the chemical composition and physical parameters of the longissimus dorsi muscle are shown in Table 4. Moisture(%, p<0.05) and crude protein(%, p<0.01) were significantly lower in pigs fed the lower level of lysine, whereas intramuscular fat(%, p<0.01) was significantly higher. Lysine level had no significant effect on crude ash content. The addition of GLA did not have any significant effect on any of the chemical parameters.

    Meat color scores(CIE L*, a*, and b*) and cooking loss(%) were significantly higher(p<0.01) in pigs fed the lower level of lysine, whereas there was no significant difference in shear force(kg/2.5 inch2) between samples. The addition of GLA did not have any significant effect on any of the physical parameters.

    Discussion

    1.Growth performance

    The juiciness and tenderness of meat plays a large role in consumers’ preference, and is affected by intramuscular fat content(Eikelenboom et al., 1996; Park et al., 1999; Fortin et al., 2005). As part of an effort to increase intramuscular fat content, previous studies have investigated methods for controlling protein and lysine levels(Goerl et al., 1995; Kerr et al., 1995; Katsumata et al., 2005). It has been shown that reduced lysine content of feed results in a reduction in growth rate(Loughmiller et al., 1998; Yamamoto et al., 2003), and Katsumata et al.(2005) reported that when lysine levels in feed are adjusted to 0.40~0.43%, the average daily gain ratio was lower and feed conversion ratio was higher than when the level reached 0.63~0.68%. In this study, we similarly found that when the lysine level in feed was lowered to 0.45%, the average daily gain decreased.

    The addition of 40% GLA extracted from evening primrose oil did not affect daily gain or feed intake. Kang & Park(2007) similarly reported that increased GLA in growing and fattening feed did not affect daily gain and feed intake; and Takada & Saitoh(1998) found that feeding 90 g of GLA oil to three breeds of hybrid hogs(body weight 69 kg) over 6 weeks on a daily basis did not have a significant effect on average daily gain, feed intake, or feed conversion ratio.

    2.Carcass traits

    Pigs that were fed the lower level of lysine had significantly lower carcass weights. However, there was no significant relationship between lysine level and carcass ratio, backfat thickness, or intramuscular content. Katsumata(2011) similarly reported that lysine level was not related to backfat thickness in pigs.

    We also found no significant effect of the addition of GLA on any of the carcass characteristics measured. In contrast, Takada & Saitoh(1998) reported that three breeds of hybrid pigs(body weight 69 kg) that were given 90 g of GLA oil for 6 weeks on a daily basis had lower backfat thickness than did pigs provided with soybean milk, as the GLA resulted in increased β-oxidation and a reduced amount of accumulated fat. The reason for this inconsistent result may be due tothe lower levels of GLA used in the present study.

    3.Meat quality

    Previous studies have shown that the provision of feed containing lower lysine results in significantly increased intramuscular fat content(Stahly et al., 1979; Kerr et al., 1995; Cisneros et al., 1996; Blanchard et al., 1999; Park et al., 2006; Moon et al., 2008a,b). In this study, we found that pigs that were fed 0.45% lysine had significantly higher intramuscular fat content than pigs that were fed 0.75% lysine. Once absorbed, lysine is synthesized into carnitine through the pig’s liver and pancreas, and is accumulated into muscles(Mayes, 1996), promoting the oxidization of fatty acids. When pigs are fed low levels of lysine, they do not have sufficient lysine for carnitine synthesis, resulting in low levels of carnitine in the loin(Katsumata, 2011). Consequently, the oxidization of fatty acids is reduced, leading to an increased level of accumulated fatty acids and thus higher intramuscular fat content(Katsumata et al., 2005; Katsumata, 2011). The addition of GLA did not significantly affect intramuscular fat content, possibly because the levels of GLA used in this study were not sufficiently high to affect the β-oxidation of fatty acids.

    Meat colors cores(CIE L*, a*, and b*) were significantly higher in pigs that were fed the lower level of lysine. Bidner et al.(2004) found that female pigs with body weight 75kg that were fed 0.57% lysine had significantly higher values of CIE L* than pigs that were fed 0.65% lysine, while no significant difference was found for CIE a* and b*. Similar result was observed for the value of CIE L, whereas the yellow and red indices produced different results. Cooking loss was also significantly higher in pigs that were fed the lower level of lysine, possibly due to the loss of fat as well as moisture. In contrast, lysine level had no significant effect on shearing force, possibly due to the high fat content of meat. The addition of GLA had no significant effect on meat color, heat loss, or shearing force, which may have been due to the low supplementation level of GLA.

    Acknowledgement

    This work was carried out with the support of the Cooperative Research Program for Agriculture Science & Technology Development(Project No. PJ00637801) Rural Development Administration, Republic of Korea.

    Figure

    Table

    Ingredients chemical compositions, and cost of the diets fed to pigs(as-fed basis, %)

    aThepremix provides the following amounts of vitamins per kilogram of diet: vitamin A, 2 000 000 IU; vitamin D3, 400 000 IU; vitamin E, 2500 IU; vitamin K3 100 mg; vitamin B1, 100 mg; vitamin B2, 300 mg; vitamin B12, 1200 mcg; niacin, 2000 mg; calcium D-pantothenate, 1000 mg; folic acid, 200 mg; biotin, 20 mg; choline chloride, 25 000 mg; Mn, 12 000 mg; Zn, 15 000 mg; Fe, 4000 mg; Cu, 500 mg; I, 250 mg; Co, 100 mg; Mg, 2000 mg; butylated hydroxytoluene, 5000 mg.
    bCalculated as proportion of the ingredient.

    Effects of dietary lysine and GLA levels on growth performance in finishing pig

    aL, lysine effects; G, gamma-linolenic acid effects; LxG, interaction of lysine and gamma-linolenic acid; NS, P>0.05
    *P>0.01
    **P>0.05

    Effects of dietary lysine and GLA levels on carcass traits in finishing pigs

    aL, lysine effects; G, gamma-linolenic acid effects; LxG, interaction of lysine and gamma-linolenic acid; NS P>0.05
    **P>0.05
    bCarcass grade results were expressed as index (A=4.0, B=3, C=2, D=1.0).

    Effects of dietary lysine and GLA levels on chemical composition and physical parameters of the longissimus dorsi muscle

    aL, lysine effects; G, gamma-linolenic acid effects; LxG, interaction of lysine and gamma-linolenic acid; NS, P>0.05
    *P>0.01
    **P>0.05
    bCIE L = black (0) to white (100); CIE a = red (+) to green (-); CIE b = yellow (+) to blue (-).

    Reference

    1. (1995) AOAC Official methods of analysis, Association of Official Analytical Chemists,
    2. Bidner BS , Ellis M , Witte DP , Carr SN , McKeith FK (2004) Influence of dietary lysine level, pre-slaughter fasting, and rendement napole genotype on fresh pork quality , Meat Sci, Vol.68 ; pp.53-60
    3. Blanchard PJ , Ellis M , Warkup CC , Hardy B , Chadwick JP , Deans GA (1999) The influence of rate of lean and subcutaneous fat tissue development on pork eating quality , Anim. Sci, Vol.68 ; pp.477-485
    4. Castell AG , Cliplef RL , Poste-Flynn LM , Butler G (1994) Performance, carcass and pork characteristics of castrates and gilts self-fed diets differing in protein content and lysine: energy ratio , Can. J. Anim. Sci, Vol.4 ; pp.519-528
    5. Cisneros F , Ellis M , Baker DH , Easter RA , Mekeith FK (1996) The influence of short-term feeding of amino acid deficient diets and high dietary leucine levels on the intramuscular fat content of pig muscle , Anim. Sci, Vol.63 ; pp.517-522
    6. Donato J Jr, Pedrosa RG , Cruzat VF , Pires ISO , Tirapegui J (2006) Effects of leucine supplementation on the body composition and protein status of rats submitted to food restriction , Nutrition, Vol.22 ; pp.520-527
    7. Eilelenboom G , Hoving-Bolink AH , Vander Wal PG (1996) The eating quality of pork - The influence of intramuscular fat , Fleisch Wirtschaft, Vol.3 ; pp.18-20
    8. Essén-Gustavsson B , Karlsson A , Lundström K , Enfält AC (1994) Intramuscular fat and muscle fibre lipid contents in halothane-gene-free pigs fed high or low protein diets and its relation to meat quality , Meat Sci, Vol.38 ; pp.269-277
    9. Fortin A , Robertson WM , Tong AKW (2005) The eating quality of Canadian pork and its relationship with intramuscular fat , Meat Sci, Vol.69 ; pp.297-305
    10. Goerl KF , Eilert SJ , Mandigo RW , Chen HY , Miller PS (1995) Pork characteristics as affected by two populations of swine and six crude protein levels , J. Anim. Sci, Vol.73 ; pp.3621-3626
    11. Heo K , Odle J , Han IK , Cho W , Seo S , Van Heugten EV , Pilkington DH (2000) Dietary L-carnitine improves nitrogen utilization in growing pigs fed low energy, fat-containing diets , J. Nutr, Vol.130 ; pp.1809-1814
    12. Hodgson RR , Davis GW , Smith GC , Savell JW , Cross HR (1991) Relationships between pork loin palatability traits and physical characteristics of cooked chops , J. Anim. Sci, Vol.69 ; pp.4858-4865
    13. Horrobin DF (1992) Nutritional and medical importance of gamma-linolenic acid , Prog. Lipid Res, Vol.31 ; pp.163-194
    14. Johnson MM , Swan DD , Surette ME , Stegner J , Chilton T , Fonteh AN , Chilton FH (1997) Dietary supplementation with -linolenic acid alters fatty acid content and eicosanoid production in healthy human , J. Nutr, Vol.127 ; pp.1435-1444
    15. Kang HK , Park BS (2007) Effects of dietary fatty acids on the fatty acid composition of pork and plasma lipids in swine , J. Korean Soc. Food Sci. Nutr, Vol.36 ; pp.563-568
    16. KAPE(Korea Institute for Animal Products Quality Evaluation)The pork carcass grading Korea Institute for Animal Products Quality Evaluation Gyungki Retrieved 1 January 2011 from http//www.ekape.or.kr/view/eng/system/pork.asp , 2011,
    17. Katsumata M (2011) Promotion of intramuscular fat accumulation in porcine muscle by nutritional regulation , Anim. Sci. J, Vol.82 ; pp.17-25
    18. Katsumata M , Kobayashi S , Matsumoto M , Tsuneishi E , Kaji Y (2005) Reduced intake of dietary lysine promotes accumulation of intramuscular fat in the Longissimus dorsi muscles of finishing gilts , Anim. Sci. J, Vol.76 ; pp.237-244
    19. Kerr BJ , McKeith FK , Easter RA (1995) Effect on performance and carcass characteristics of nursery to finisher pigs fed reduced crude protein, amino acid-supplemented diets , J. Anim. Sci, Vol.73 ; pp.433-440
    20. Loughmiller JA , Nelssen JL , Goodband RD , Tokach MD , Titgemeyer EC , Kim IH (1998) Influence of dietary lysine on growth performance and carcass characteristics of late-finishing gilts , J. Anim. Sci, Vol.76 ; pp.1075-1080
    21. Murray RK , Granner DK , Mayes PA , Rodwell VW , Mayes PA (1996) Oxidation of fatty acids ketogenesis , Harpers biochemistry Appleton and Lange, Stamford. CT, ; pp.224-235
    22. Moon HK , Lee SD , Jung HJ , Kim YH , Park JC , Ji SY , Kim CD , Kwon OS , Kim IC (2008) Effects of dietary protein level and supplementation of conjugated linoleic acid on growth performance and meat quality parameters in finishing pigs , J. Anim. Sci. Technol, Vol.50 ; pp.695a-704a
    23. Moon HK , Lee SD , Jung HJ , Kim YH , Park JC , Ji SY , Kwon OS , Kim IC (2008) Effects of dietary lysine and leucine levels on growth performance and meat quality parameters in finishing pigs , Anim. Sci. Technol, Vol.50 ; pp.687b-694b
    24. (1998) NRC Nutrient requirements of swine, The National Academies Press,
    25. Park BY , Yoo YM , Kim JH , Cho SH , Kim ST , Lee JM , Kim YK (1999) Effect of intramuscular fat contents on meat qualities of pork loins , Kor. J. Anim. Sci, Vol.41 ; pp.59-64
    26. Park JC , Kim YH , Jung HJ , Lee SD , Cho KH , Kim IC , Lee SJ , Moon HK (2006) Effects of dietary L-leucine levels in low-lysine diets on growth performance and meat quality parameters in finishing duroc pigs , J. Anim. Sci. Technol, Vol.48 ; pp.813-818
    27. SAS (1995) SAS Software for PC , Version 6 SAS Institute Inc. Cary NC. USA,
    28. Sayanova O (1998) Gamma-linolenic acid , Biol. Scie. Rev, Vol.11 ; pp.19-22
    29. Stahly TS , Cromwell GL , Aviotti MP (1979) The effect of environmental temperature and dietary lysine source and level on the performance and carcass characteristics of growing swine , J. Anim. Sci, Vol.49 ; pp.1242-1251
    30. Takada R , Saitoh M (1998) Effect of dietary linolenic acid-enriched oil on backfat thickness and liver fatty acid degrading enzyme activity in growing pigs , Anim. Sci. Technol, Vol.69 ; pp.433-438
    31. Witte DP , Ellis M , McKeith FK , Wilson ER (2000) Effect of dietary lysine level and environmental temperature during the finishing phase on the intramuscular fat content of pork , J. Anim. Sci, Vol.78 ; pp.1272-1276
    32. Yamamoto A , Satoh Y , Nakamura K , Itoh M , Furuya S (2003) Effects of feeding a lower protein diet supplemented with the apple pomace on growth performance, nitrogen excretion and backfat thickness in finishing pigs , Jpn. J. Swine Sci, Vol.40 ; pp.129-134
    33. Zurier RB , Rossetti RG , Jacobson EW , DeMarco DM , Liu NY , Temming JE , White BM , Laposata M (1996) Gamma-linolenic acid treatment of rheumatoid arthritis A randomized placebocontrolled trial , Arthritis Rheu, Vol.39 ; pp.1808-1817
    오늘하루 팝업창 안보기 닫기