Livestock Science 142 (2011) 121–127

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Effect of crossbreeding with exotic breeds on meat quality of Awassi lambs

Abdullah Y. Abdullah⁎, Rasha I. Qudsieh, Basheer M. NusairatDepartment of Animal Production, Faculty of Agriculture, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan

a r t i c l e i n f o

⁎ Correspondingauthor. Tel.:+96227201000x22255E-mail address: abdullah@just.edu.jo (A.Y. Abdulla

1871-1413/$ – see front matter © 2011 Elsevier B.V.doi:10.1016/j.livsci.2011.07.002

a b s t r a c t

Article history:Received 13 May 2010Received in revised form 12 May 2011Accepted 11 July 2011

The influence of genotype on fattening performance andmeat qualitywas studied inmale lambsof five genotypes (n=10): CA (F1 Charollais–Awassi), ACA (B1 Awassi–Charollais–Awassi),RA (F1 Romanov–Awassi), ARA (B1 Awassi–Romanov–Awassi) and A (Awassi). Lambs wereweaned at 70 days of age and offered a diet containing 16% CP and 2.78 Mcal metabolizableenergy/kg for 170 days. At the end of the fattening period, all lambs were slaughtered andMusculus semitendinosus andMusculus longissimuswere excised from the right and left sides ofthe carcass for objective meat quality assessment. Birth weights were similar while weaningweights differed among genotypes being greater for the CA. The final and fasted live weightswere found to be significantly affected by genotype; the CA genotype was heavier than A andARA while the ACA genotype was heavier than A. Hot and cold carcass weights and dressing%differed significantly with CA genotype having greater values than A, while the remaininggenotypes had intermediate values. Meat quality parameters for M. semitendinosus weredifferent among genotypes with Awassi having higher cooking loss%, and hue angle values butlower redness values than the remaining genotypes. Yellowness values were higher for A andARAgenotype than CAandRA genotypeswhile ACA genotypewas intermediate. Expressed juice% was the lowest for A and ARA genotypes. Lightness values forM. semitendinosuswere greaterfor ARA and A genotypes, with no differences between A and ACA genotypes. However, M.longissimus had only greater lightness values for A and ARA with no significant differencesbetween ARA, ACA and RA genotypes. Meat quality parameters for M. semitendinosus wereaffected by aging duration being significantly higher for pH, yellowness and hue angle, andlower for redness at 24 h compared to 7 days of aging. No differences were observed in all meatquality parameters for M. longissimus except in pH and cooking loss% being lower at 7 days ofaging. Variation between muscles within each genotype was observed in cooking loss%, shearforce values, lightness and redness. Results of this study indicate that the F1 crossbreeding ofAwassi with either Charollais or Romanov yielded higher production in the resulting genotypewhile B1 progeny was intermediate without any adverse effects on meat quality. Additionally,aging for 7 days lowered pH and increased redness in both muscles.

© 2011 Elsevier B.V. All rights reserved.

Keywords:AwassiCharollaisRomanovWeightMeat quality

1. Introduction

Improving productive and reproductive traits can beperformed using several approaches. According to Clarkeet al. (1984), breeds that have the potential to improveprofitability are those with high mature weights, genetic

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predisposition to leanness and high meat yield. Awassi is amulti-purpose fat-tailed sheep breed that predominates inJordan and the Middle East. Fat-tail evolved as an adaptiveresponse to harsh environmental conditions. Awassi usesthe fat stored in its tail when food is scarce (Epstein, 1985).Fat deposited in the body or tail has increased costs interms of feed energy compared to lean meat deposition.Also, consumers prefer to select lean meat with less fat.Therefore, reducing the size of the fat tail or removing itcould reduce the amount of fat deposited and redirect

122 A.Y. Abdullah et al. / Livestock Science 142 (2011) 121–127

nutrients to depositing lean rather than fat (Marai andBahgat, 2003). Several studies have been conducted toimprove the productivity of Awassi by crossbreedingAwassi with exotic breeds (Abdullah et al., 2003; MomaniShaker et al., 2002). Awassi has been crossed with Charollais toimprove carcass characteristics and with Romanov to improvereproductive traits of the first generation (F1). Awassi sheep isknown for its fat tail thatmay represent up to 10% of the carcassweight in ram lambs slaughtered at 40 kg of live weight(Abdullah and Qudsieh, 2008). However, this percentage wasreduced in F1 Charollais×Awassi and F1 Romanov×Awassicrossbreeds (Abdullah et al., 2003).

Crossbreeding has been shown to influence meat andcarcass qualities. Dawson and Carson (2002) reported thatTexel lambs sired by high lean growth index sires had reducedlipid content. Meat quality can also be influenced by aging asAbdullah and Qudsieh (2009) reported that tenderness wasimproved inmuscles aged for 7 days at 4 °Cwhen compared tonon-aged muscles. Meat quality characteristics have beeninvestigated in Awassi sheep (Abdullah and Qudsieh, 2009).However, meat qualities of crossbreeds of Awassi with exoticbreeds have not been investigated. Therefore, the aim of thisstudy is to investigate the influence of crossbreeding ongrowth performance and meat quality characteristics of CA(F1 Charollais–Awassi), ACA (B1 Awassi–Charollais–Awassi), RA(F1 Romanov–Awassi), ARA (B1 Awassi–Romanov–Awassi) andA (Awassi).

2. Materials and methods

2.1. Animals and management

The experiment was conducted at the Center of Agricul-tural Research and Production at the Jordan University ofScience and Technology. Fifty male lambs were used in thetrial. All lambs were obtained from the sheep flock born inwinter (late October/late December). Lambs from five differentgenotypes (n=10 per group), CA (F1 Charollais–Awassi), ACA(B1 Awassi–Charollais–Awassi), RA (F1 Romanov–Awassi), ARA(B1 Awassi–Romanov–Awassi) and A (Awassi), were raisedwith their dams until weaning at 70 days of age. Afterweaning,lambs were separated from their dams and reared in tenadjacent open sided pens allocating five males from eachgenotype per pen. All lambs were introduced slowly to adlibitum access to a diet containing 16% CP and 2.78 Mcalmetabolizable energy/kg for a period of 170 days (NationalResearch Council, 1985), and free access to clean water. Theingredients of the totally mixed ration were soybean 10%,barley 65.5%, wheat bran 7.5%, straw 15%, salt 1%, limestone 1%andminerals and vitamins (vitamin A, 450,000 IU; vitamin D3,1,100,0000 IU; vitamin E, 3.18 g; Mn, 10.9 g; I, 1.09 g; Zn,22.73 g; Fe, 22.73 g; Cu, 2.73 g; Co, 0.635; Mg, 100 g; Se, 0.1 g).Birth, weaning and final live weights were recorded for alllambs. At the end of the fattening period, all male lambs wereslaughtered at the same time for subsequent meat qualitymeasurements.

2.2. Slaughter procedure and carcass measurements

Lambs were slaughtered at 240 days of age. Each animalwas weighed after a 12-h fasting period to obtain the fasted

weight. Lambs were slaughtered using the normal commer-cial procedure described by Abdullah et al. (1998). Hotcarcasses were weighed after dressing and recorded, thenwere chilled at 4 °C for 24 h. After chilling, the cold carcassweight was measured and recorded. For objective meatquality assessment, Musculus semitendinosus and longissimuswere excised from both right and left sides of the carcass andvacuum-packaged. Muscles from the right sides were used formeat quality measurements after 24 h of slaughter, whilemuscles from the left side were stored chilling at 4 °C for7 days (aging), then meat quality measurements wereconducted. M. semitendinosus was excised from the leg,while M. longissimus was excised from the carcass by cuttingbetween the 12th and 13th thoracic vertebrae and the legs.

2.3. Meat quality measurements

For objective meat quality assessment, each muscle wascut into slices and each slice was designated for a specificmeat quality measurement as described by Abdullah andQudsieh (2009), where the designated slice was consistentfor all muscles. Meat quality parameters measured were color,pH, cooking loss%, expressed juice% and shear force values.Color of the muscles was immediately measured after aging.Samples were placed on polystyrene trays with the fresh cut ofthe slice facing upward, then they were covered with a plasticoxygen-permeable film and were allowed to oxygenate for 3 hat 2 °C (Geesink et al., 2000). A colorimeter device (12MMAperture U 59730-30, Cole-Parameter International, AccuracyMicrosensors Inc., Pittsford, New York, USA) was used toobjectively measure CIELAB (Commission International del'Eclairage) lightness (L*), redness (a*) and yellowness (b*).Hue (H=Tan−1b*/a*) and chroma {C=(a2+b2)1/2} were alsomeasured (Young and West, 2001). Duplicate 25 mm sliceswere placed in plastic bags and immersed in a thermostaticallycontrolled water bath at 70 °C for 90 min to achieve internaltemperature of 70 °C (Purchas, 1972). Cooked samples weredried with paper towels and re-weighed to determine cookinglosses. Cooked slices were kept over night in a chiller at 4 °Cand cores (6–12) of (10 mm)2/cross section were cut the nextday and sheared in a direction perpendicular to the musclefibers using a Warner–Bratzler (WB) shear blade with thetriangular slot cutting edge mounted on the Salter Model 235(Warner–Bratzler meat shear, G-R Manufacturing Co. 1317Collins LN, Manhattan, Kansas 66502, USA) to determine thepeak force required to shear the samples. Expressed juice wasdetermined in terms of expressed juice values (water expelled)and was based on measuring the loss of water liberated byapplying a pressure of 2.5 kg for 5 min on the muscle tissue,where itwas calculated as a percent of initialweight: expressedjuice (%)=(initial wt−final wt)×100/initial wt. Expressedjuice was measured using the method described by Grau andHamm (1953) and modified by Sa udo et al. (1986).

Muscle pH was measured in duplicate diced samples in ahomogenate of 2 g (using Ultra Turrax T8 homogenizer) in10 ml of neutralized 5-mM iodoacetate reagent. The pH of thehomogenate was measured at around 20 °C using a pH meter(pH Spear, large screen, waterproof pH/temperature tester,double injection, Model 35634-40, Eurotech Instruments,Malaysia).

123A.Y. Abdullah et al. / Livestock Science 142 (2011) 121–127

2.4. Statistical analysis

Collected data were analyzed using statistical analysis andGLM procedure of SAS (SAS Institute, 2000). The experimentwas analyzed as a split plot design with strip, with genotypebeing the main treatment and the muscle type as splittreatment, and aging was considered as the strip factor. Theleast squares means were calculated for all measuredvariables using the LSMEANS statement.

3. Results and discussion

3.1. Growth performance

Table 1 shows birth, weaning, final and fasted liveweights,hot and cold carcass weights and dressing%. Birth weightswere comparable (PN0.05) between all genotypes. Weaningweights were significantly affected by genotype at which CAhad the highest weight with comparable values between ACAand RA, and also between ARA and A genotypes. Final andfasted live weights were the lowest (Pb0.05) in A and ARA,but the final live weight of ARA genotype did not differ thefrom the ACA genotype; whereas, for the fast live weight,there were no significant differences between the ARAgenotype and the ACA and RA genotypes. Hot and coldcarcass weights were higher (Pb0.05) in CA than in Agenotype; as for the hot carcass weight of CA genotype, ithas no significant differences from ACA, RA and ARAgenotypes, whereas, the cold carcass weight of CA iscomparable to the ARA genotype. Dressing% was numericallythe highest for CA and statistically comparable (PN0.05) withACA and RA genotypes. This could possibly be due to the factthat Charollais breed is a meat type breed and their geneshave transferred to CA crossbreed; therefore, they producedhigher live weights and carcass weights. Also, differences inlive weights could be explained by the differences amongbreeds in production type and mature body weights(Abdullah et al., 2003 and Momani Shaker et al., 2002).

Several studies compared the growth performance ofdifferent breeds (Hill et al., 1993) and crosses (Abdullah et al.,2003; Hassan et al., 1996). No significant growth differenceswere found between Awassi and Coopworth breeds (Hill et al.,1993). First crosses normally have better growth performance

Table 1Least-squares means of birth, weaning, final and fast live weights, hot and cold carcas

Variable Genotype1

CA ACA

Live weights (kg)Birth 4.6±0.2 4.5±0.2Weaning 20.8±0.8a 17.5±0.8b

Final 62.2±4.0a 56.1±4.0ab

Fast 57.9±4.0a 52.2±4.0ab

Carcass weights (kg)Hot carcass 27.3±0.5a 26.0±0.4ab

Cold carcass 26.1±0.4a 24.7±0.4bc

Dressing% 53.6±0.9a 51.3±0.9ab

a,b,c Means in the same row, bearing different superscript letters differ.1Genotype: CA=F1 Charollais–Awassi, ACA=B1 Awassi–Charollais–Awassi, RA=genotype.

than reciprocal (back) crosses (Hassan et al., 1996). Severalstudies have compared hot and cold carcass weights betweendifferent genotypes of sheep and between pure and crossbredanimals (Bourifa and Touchberry, 1993; Crouse et al., 1981;Esenbuga et al., 2001; Fadili and Leroy, 2000; Kashan et al.,2005; Solomon et al., 1980).

3.2. Genotype effect on meat quality

Tables 2 and 3 show data for meat quality parametersmeasured on M. semitendinosus and longissimus, respectively.pH measured after aging for both M. semitendinosus andlongissimus (Tables 2 and 3)was comparable (PN0.05) amongthe different genotypes and was within the range acceptablefor meat. Smulders et al. (1992) determined a range of pHdecline from 7 upon slaughter to reach approximately 5.3–5.8in sheep. Meat tenderness was also comparable (PN0.05)among the different genotypes (Tables 2 and 3) in bothM. semitendinosus and longissimus. Ekiz et al. (2009) did notreport any significant differences in the pH of Turkish breeds.Martinez-Cerezo et al. (2005) also did not find significantdifferences in the pH measured after 24 h post-mortemamong Rasa Aragonesa, Churra and Spanish Merino lambs,and Sanudo et al. (1997) did not report any pH differencesamong Churra, Castellana, Manchega and Awassi crosses.However, other studies reported differences in the ultimatepH among sheep genotypes (Hoffman et al., 2003; Sanudoet al., 2003).

Variations in pH among breeds were generally explainedby the differences in glycolytic potential (Hopkins andFogarty, 1998) or pre-slaughter handling (Santos et al.,2007). A significant difference between sheep genotypes interms of tenderness has been reported by several authors(Burke and Apple, 2007; Hoffman et al., 2003; Sanudo et al.;,2003). Other researchers reported no effect of genotype ofbreed on shear force values (Hopkins and Fogarty, 1998;Sanudo et al., 1997). In the current study, Warner Bratzlershear force values reported were comparable with reports ofChurra, Castellana, Manchega and Awassi lambs (Sanudoet al., 1997) and Dorper, Katahdin, St. Croix and Suffolk lambs(Burke and Apple, 2007). Esenbuga et al. (2001) reportedhigher values of shear force for the fat tailed genotype(Awassi, Red Karaman, Tushin, and Awassi×Tushin) than

s weights, and dressing-out percentages for ram lambs of different genotypes.

RA ARA A

4.7±0.2 3.9±0.2 4.6±0.218.1±0.8b 15.2±0.8c 15.4±0.8c

61.9±4.0a 51.2±4.0bc 43.9±4.0c

56.3±4.0ab 47.9±4.0bc 41.1±4.0c

26.2±0.5ab 26.1±0.6ab 25.3±0.5b

24.6±0.4bc 24.9±0.4ab 23.5±0.4c

51.8±0.9ab 49.6±0.9bc 47.1±0.9c

F1 Romanov–Awassi, ARA=B1 Awassi–Romanov–Awassi, A=pure Awassi

Table 2Meat quality parameters of semitendinosus muscle as affected by ram lamb genotypes.

Variable Genotype1 P-value

CA ACA RA ARA A

pH 5.71±0.11 5.95±0.11 5.71±0.11 5.92±0.11 5.78±0.11 0.41Cooking loss (%) 38.1±0.8c 39.1±0.8b 39.1±0.8b 39.9±0.8b 41.9±0.8a 0.03Expressed juice (%) 20.5±0.7b 21.2±0.7b 22.8±0.7a 18.6±0.7c 18.6±0.7c 0.001Shear force (kg/cm2) 4.55±0.3 3.91±0.3 4.64±0.3 4.43±0.3 5.14±0.3 0.09

Color coordinatesL* (lightness) 42.95±1.0c 44.57±1.0bc 42.67±1.0c 46.78±1.0a 45.85±1.0ab 0.02a* (redness) 3.69±0.34a 3.46±0.34a 3.62±0.34a 3.16±0.34a 2.08±0.34b 0.01b* (yellowness) 12.77±0.6b 14.21±0.6ab 12.78±0.6b 14.53±0.6a 14.86±0.6a 0.05Chroma 13.3±0.6 14.7±0.6 13.3±0.6 15.0±0.6 15.0±0.6 0.09Hue angle 74.9±1.8b 76.1±1.8b 73.9±1.8b 76.8±1.8b 81.8±1.8a 0.03

a,b,c Means in the same row, bearing different superscript letters differ according to the indicated P-value.1Genotype: CA=F1 Charollais–Awassi, ACA=B1 Awassi–Charollais–Awassi, RA=F1 Romanov–Awassi, ARA=B1 Awassi–Romanov–Awassi, A=pure Awassigenotype.

124 A.Y. Abdullah et al. / Livestock Science 142 (2011) 121–127

that of reported in the current study. Sobrinho et al. (2003)reported shear force differences between lambs sired bydifferent genotypes.

The cooking loss% of M. semitendinosus (Table 2) wasinfluenced by genotype (Pb0.05). Cooking loss% was thehighest in Awassi compared to the other genotypes and thelowest in CA with no differences among ACA, RA and ARAgenotypes. Differences in the cooking loss% could be due todifferences in the initial amount of water in muscles.However, the cooking loss% ofM. longissimuswas comparable(PN0.05) among the different genotypes (Table 3).

The expressed juice% of M. semitendinosus (Table 2) wasalso influenced by genotype (Pb0.05), where muscles withhigher cooking loss% had lower expressed juice%. Expressedjuice% was comparable between ARA and A, while thepercentage was the highest in RA. Expressed juice% ofM. longissimuswas comparable (PN0.05) among the differentgenotypes (Table 3). Ekiz et al. (2009) reported that breedhad no influence on the cooking loss%, but influenced theshear force and redness of Turkish Merino, Ramlic, Kivircik,Chios, and Imroz meat.

Several researchers reported differences in the cookingloss% between genotypes (Esenbuga et al., 2001; Hopkins andFogarty, 1998), while other researchers reported no signifi-

Table 3Meat quality parameters of longissimus muscle as affected by ram lamb genotypes.

Variable Genotype1

CA ACA RA

pH 5.59±0.1 5.75±0.1 5.6Cooking loss (%) 27.6±1.5 29.3±1.5 27Expressed juice (%) 21.5±1.2 20.8±1.2 21Shear force (kg/cm2) 2.28±0.2 1.49±0.2 1.8

Color coordinatesL* (lightness) 36.58±1.1c 40.43±1.1b 38.2a* (redness) 5.39±0.4 5.57±0.4 5.3b* (yellowness) 10.90±1.4 11.72±1.4 10.5Chroma 12.5±1.1 13.2±1.1 12Hue angle 60.6±4.6 62.3±4.6 57

a,b,c Means in the same row, bearing different superscript letters differ according to1Genotype: CA=F1 Charollais–Awassi, ACA=B1 Awassi–Charollais–Awassi, RA=genotype.

cant effect of lamb genotype on the cooking loss% (Hoffmanet al., 2003).

Lightness (L*) was influenced by genotype (Pb0.05) in bothM. semitendinosus and longissimusmuscles. Lightness values forM. semitendinosuswere greater for ARA and A genotypes, withno differences between A and ACA genotypes. However,M. longissimus had greater lightness values for A and ARAwith no significant differences between ARA, ACA and RAgenotypes. Redness (a*) was the lowest in A genotype withcomparable results among the different genotypes. Yellowness(b*) for M. semitendinosus was lower in CA and RA genotypesthan the other genotypes while CA and RA genotypes did notdiffer significantly from ACA genotype (Table 2). This was inaccordance with L* where CA and RA had lower L* values.However, yellowness was comparable among the differentgenotypes in M. longissimus (Table 3).

Chroma, which is a measurement of color intensity,tended (0.05bPb0.10) to be lower in the M. semitendinosusof CA and RA compared to other genotypes (Table 2). Hueangle was the highest in A genotype with comparable resultsamong the different genotypes (Table 2). In the case ofM. longissimus chroma and hue angle values were comparableamong the different genotypes. Meat color is one criterion bywhich consumers judge meat quality. Consumers of the

P-value

ARA A

3±0.1 5.89±0.1 5.58±0.1 0.14.7±1.5 28.2±1.5 29.8±1.5 0.81.6±1.2 21.7±1.2 21.4±1.2 0.997±0.2 1.91±0.2 2.03±0.2 0.17

4±1.1bc 41.04±1.1ab 43.61±1.1a 0.0019±0.4 5.31±0.4 5.40±0.4 0.372±1.4 12.87±1.4 12.60±1.4 0.68.5±1.1 14.4±1.1 14.4±1.1 0.55.9±4.6 63.4±4.6 61.0±4.6 0.94

the indicated P-value.F1 Romanov–Awassi, ARA=B1 Awassi–Romanov–Awassi, A=pure Awass

i

125A.Y. Abdullah et al. / Livestock Science 142 (2011) 121–127

Mediterranean countries prefer to consume pale or pink lambmeat (Santos-Silva et al., 2002). Esenbuga et al. (2009) didnot report significant differences in color parameters (L*, a*,b*, hue and chroma) between Awassi and Morkaramanbreeds. Dawson et al. (2002) reported that meat color interms of lightness, yellowness and chroma values was notaffected by ewe genotype, ram breed nor ram source. Resultsare consistent with findings of Fogarty et al. (2000).

3.3. Aging time effect on meat quality

Aging for 24 h or 7 days had no influence (PN0.05) on thecooking loss%, expressed juice% nor the shear force ofM. semitendinosus; however, pH values were higher(Pb0.05) in muscles aged for 24 h (Table 5). This couldpossibly be due to the glycolytic enzymes activity thatcontinued to act during the aging time and resulted inlowering pH after 7 days. As a general rule increasing theaging time will increase the tenderness (Abdullah andQudsieh, 2009). Our result is not inconsistentwith the generalrule. This may be due to the aging process that did not bringabout any significant change in tenderness after 24 h up to

Table 4Differences in meat quality parameters of longissimus and semitendinosus muscles w

Variable Muscle Genotype1

CA

pH Longissimus 5.59Semitendinosus 5.71S.E. 0.11P-value 0.48

Cooking loss% Longissimus 27.6Semitendinosus 38.1S.E. 1.24P-value 0.001

Expressed juice% Longissimus 21.5Semitendinosus 20.5S.E. 1.23P-value 0.57

Lightness (L*) Longissimus 36.58Semitendinosus 42.95S.E. 0.79P-value 0.001

Redness (a*) Longissimus 5.39Semitendinosus 3.69S.E. 0.33P-value 0.001

Yellowness (b*) Longissimus 10.90Semitendinosus 12.77S.E. 0.84P-value 0.13

Chroma Longissimus 12.5Semitendinosus 13.3S.E. 0.60P-value 0.33

Hue angle Longissimus 60.6Semitendinosus 74.9S.E. 3.9P-value 0.02

Shear force (kg/cm2) Longissimus 2.28Semitendinosus 4.55S.E. 0.33P-value 0.001

1Genotype: CA=F1 Charollais–Awassi, ACA=B1 Awassi–Charollais–Awassi, RA=genotype. Muscles are compared within each column for each variable.

7 days. Tenderization is primarily dependent on postmortemproteolysis mediated by proteolytic enzymes such as calpainsand lysosomal proteases (Koohmaraie, 1994). Improvementoccurs as a consequence of the degradation of muscle structurethat reduces myofibrillar strength (Ouali, 1990). Lightness andchroma were comparable (PN0.05) in M. semitendinosus agedeither for 24 h or 7 days (Table 5). Redness and yellownesswere influenced (Pb0.05) by aging. Redness increased andyellowness decreased as aging time increased from 24 h to7 days. Thehueangle decreased (Pb0.05)with increasingagingtime, meaning that color became less definite as aging timeincreased in M. semitendinosus (Table 5).

In M. longissimus (Table 6), pH values were lower(Pb0.05) in muscles aged for 7 days. Trend in the pH declinewas consistent with pH inM. semitendinosus; however, valuesof pH at 24 h and shear force values at 24 h and 7 days ofaging were lower in M. longissimus than M. semitendinosus.Cooking loss% decreased (Pb0.001) as aging time increased;however, the expressed juice% and shear force values werecomparable at both aging times. Our findings are inagreement with Abdullah and Qudsieh (2009) and Daviset al. (1975) who reported that aging for 7 days reduced

ithin each ram lamb genotype.

ACA RA ARA A

5.75 5.63 5.89 5.585.95 5.71 5.92 5.780.14 0.11 0.16 0.120.34 0.60 0.91 0.23

29.3 27.7 28.2 29.839.1 39.1 39.9 41.91.43 1.11 1.75 1.800.001 0.001 0.001 0.001

20.8 21.6 21.7 21.421.2 22.8 18.6 18.61.00 0.94 1.02 0.730.78 0.38 0.05 0.01

40.43 38.24 41.04 43.6144.57 42.67 46.78 45.851.03 0.93 1.49 0.750.01 0.001 0.01 0.055.57 5.39 5.31 5.403.46 3.62 3.16 2.080.4 0.38 0.41 0.400.001 0.001 0.001 0.001

11.72 10.52 12.87 12.6014.21 12.78 14.53 14.860.94 0.59 1.38 1.630.08 0.01 0.40 0.25

13.2 12.5 14.4 14.414.7 13.3 15.0 15.00.82 0.46 1.22 1.070.20 0.20 0.69 0.67

62.3 57.9 63.4 61.076.1 73.9 76.8 81.82.9 2.4 3.2 4.30.002 0.001 0.01 0.0021.49 1.87 1.91 2.033.91 4.64 4.43 5.140.25 0.19 0.28 0.240.001 0.001 0.001 0.001

F1 Romanov–Awassi, ARA=B1 Awassi–Romanov–Awassi, A=pure Awassi

Table 5Meat quality parameters of pooled semitendinosus muscles from fivegenotypes1 of ram lambs aged for different periods.

Variable Aging time P-value

24 h 7 days

pH 6.14±0.07 5.49±0.07 0.001Cooking loss (%) 39.6±0.5 39.6±0.5 0.92Expressed juice (%) 20.1±0.4 20.6±0.4 0.42Shear force (kg/cm2) 4.51±0.2 4.56±0.2 0.85

Color coordinatesL* (lightness) 44.42±0.6 44.71±0.6 0.76a* (redness) 2.84±0.2 3.56±02 0.02b* (yellowness) 14.38±0.4 13.27±0.4 0.05Chroma 14.7±0.4 13.8±0.4 0.10Hue angle 78.5±1.1 75.0±1.1 0.03

1Genotype; F1 Charollais–Awassi, B1 Awassi–Charollais–Awassi, F1Romanov–Awassi, B1 Awassi–Romanov–Awassi, pure Awassi.

126 A.Y. Abdullah et al. / Livestock Science 142 (2011) 121–127

cooking loss% in M. longissimus. Color coordinates measuredwere not influenced (PN0.05) by aging (Table 6), while a* andchroma tended (0.05bPb0.10) to be lower at 24 h of aging.

3.4. Effect of muscle variation within each genotype on meatquality

Table 4 demonstrates meat quality differences betweenmuscles within each genotype, where pH and chromawere comparable (PN0.05) between M. semitendinosus andlongissimus. Cooking loss% was influenced by muscles. Gener-ally, cooking loss% was higher (Pb0.001) in M. semitendinosusfor all genotypes. Our findings were consistent with Abdullahand Qudsieh (2009) in Awassi and Sobrinho et al. (2003) inRomney sheepbreeds. Differences in the expressed juice%wereonly observed in ARA and A genotypes where values werehigher (Pb0.05) in M. longissimus for both ARA and Agenotypes. From comparing the measured color coordinates,lightnesswas higher (Pb0.05) and rednesswas lower (Pb0.05)in M. semitendinosus for all genotypes. Results are similar toprevious findings of Abdullah and Qudsieh (2009). Yellownesstended (0.05bPb0.10) to be higher in theM. semitendinosus ofACA and was higher (Pb0.01) in the M. semitendinosus of RA.The hue angle was influenced by muscle (Pb0.05) for all

Table 6Meat quality parameters of pooled longissimus muscles from five genotypes1

of ram lambs aged for different periods.

Variable Aging time P-value

24 h 7 days

pH 5.87±0.06 5.50±0.06 0.001Cooking loss (%) 32.7±1.0 24.4±1.0 0.001Expressed juice (%) 21.9±0.7 20.9±0.7 0.36Shear force (kg/cm2) 1.84±0.1 2.00±0.1 0.42

Color coordinatesL* (lightness) 39.78±0.7 40.19±0.7 0.68a* (redness) 5.26±0.3 5.96±0.3 0.07b* (yellowness) 10.88±0.86 12.65±0.86 0.17Chroma 12.5±0.7 14.2±0.7 0.07Hue angle 60.3±2.9 61.7±2.9 0.73

1Genotype; F1 Charollais–Awassi, B1 Awassi–Charollais–Awassi, F1Romanov–Awassi, B1 Awassi–Romanov–Awassi, pure Awassi.

genotypes and was higher in the M. semitendinosus of allgenotypes.

Shear force values were also influenced (Pb0.001) bymuscle variation in all genotypes. Values measured forM. longissimus were lower (Pb0.05) in all genotypescompared to values of M. semitendinosus. Our finding isconsistent with results obtained by Abdullah and Qudsieh(2009). This could be due to biological location and activitydifferences among the muscles which are affected by fibersize and fiber type composition (Solomon et al., 1980).

4. Conclusion

In the current study, carcass and meat quality character-istics of lambs were compared from five different genotypeswhichwere fattened in the same intensive production systemand slaughtered at the same age. Carcass characteristics andmeat quality parameters were significantly influenced bygenotype. Results of this study indicate that the F1 cross-breeding of Awassi with either Charollais or Romanov yieldedhigher production in the resulting genotype while B1 progenywas intermediate without any adverse effect onmeat quality;also, aging for 24 h or 7 days affected only the pH and colorparameter which resulted in lowering pH and more rednesswhen muscles were aged for 7 days. Charollais and Romanovwere not native sheep breeds of Jordan; crossbreeding themwith Awassi improved the performance of F1 and B1 crosses;also, meat quality of the genotype was comparable andacceptable.

Acknowledgements

The authors wish to thank the Deanship of ScientificResearch at Jordan University of Science and Technology forthe financial support of this project. Thanks are expressed tothe personnel from Jordan University of Science andTechnology for their technical assistance. The authors alsowish to acknowledge the staff of the Agricultural Center forResearch and Production for their assistance during animalslaughter.

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