COBISS: 1.08 Agris category code: Q04 EFFECT OF CARCASS WEIGHT AND GENDER ON MAIN TISSUE DISTRIBUTION IN CARCASS MAIN CUTS Boris LUKIC Ivona DURKIN 2, Laura VARGOVIC 3, Mima DADIC 4, Robert SPAIC 3, Velimir SILI 3, Goran KUSEC 2 ABSTRACT The present study was carried out on 99 pig carcasses originated from PIC hybrid pigs slaughtered in PIK Vrbovec slaughterhouse. Animals were reared in the same environmental conditions and fed the same diet. Carcasses were dissected using PIK commercial method of cutting and dissection. From the 4 main cuts, shoulder, ham, loin and ribs, main tissues were dissected: lean, subcutaneous fat with skin and bones, respectively. According to carcass weight, carcasses were divided into 6 weight groups as follows; 120 kg, 130 kg, 140 kg, 150 kg, 160 kg and 170 kg. The objective of this study was to explore the effect of carcass weight and gender on the distribution of commercially dissected lean, fat and bone tissues in the main parts of pig carcass and to analyse the same components between six weight groups. It is confirmed that the gender had a significant effect on fat content. Lean meat content was reduced with increasing carcass weight, while the fat content increases with higher carcass weights. Declining trend is found by observing the relative values of bone content with significant differences between the lightest and heaviest groups. Key words: pigs / gender / carcass weight / carcass composition / commercial dissection / main cuts 1 INTRODUCTION Growth and distribution of muscle tissue in pig carcasses has been extensively investigated (Tess et al., 1986; Wagner et al., 1999; Wiseman et al., 2007; Kusec et al., 2010). Consequently, the acquired knowledge was used for production of pigs with carcasses that contain increased muscle and decreased fat content (Wiseman et al., 2007). Trends in live slaughter weight, and not only concerning muscle content, have been changed. Reeds et al. (1993) review shows that over the last 50 years, muscle content has increased by 86%, while the live weight of pigs of the same age has increased by 20%. For the past ten years, similar pattern to the aforementioned one can be found in Croatia. Live slaughter weight, for instance increased from 102.10 kg in 2002 to 108.5 kg in 2011, while the meat percentage increased from 54.80% to 58.39% (Croatian Agricultural Agency, 2011). The highest accuracy to determine carcass composition of main tissues would be full carcass dissections. However, this methodology is expensive and laborious to perform (Beattie et al., 1999) so the commercial butcher dissection offers a faster, cheaper and acceptable solution to determine composition of muscle and fat tissues. The objective of this study was to explore the effect of carcass weight and gender on the distribution of commercially dissected lean, fat and bone tissues in the main parts of the carcass and to analyse the same components between six weight groups. 1 Fac. of Agriculture in Osijek, Kralja Petra Svačica 1d, 31000 Osijek, Croatia, e-mail: blukic@pfos.hr 2 Same address as 1 3 Belje Inc., Industrijska zona 1, Mece, 31326 Darda, Croatia 4 Ministry of Agriculture, Ulica grada Vukovara 78, 10000 Zagreb, Croatia 2 MATERIAL AND METHODS 3 RESULTS AND DISCUSSION The present study was carried out on 99 pig carcasses originated from PIC hybrid pigs slaughtered in PIK Vrbovec slaughterhouse. Animals were reared in the same environmental conditions and fed the same diet. Carcasses were dissected using PIK commercial method of cutting and dissection. From the 4 main cuts, shoulder, ham, loin and ribs, main tissues were dissected, loin, subcutaneous fat with skin and bones, respectively. According to carcass weight, carcasses were divided into 6 weight groups as follows; 120 kg (lower than 125 kg; N = 15), 130 kg (between 125 kg and 135 kg; N = 17), 140 kg (between 135 kg and 145 kg; N = 15), 150 kg (between 145 kg and 155 kg; N = 18), 160 kg (between 155 kg and 165 kg; N = 17) and 170 kg (higher than 165 kg; N = 17). The data was analysed using General Linear Model program to test the carcass weight and gender as main effects on the examined carcass tissue components. If the effect of weight group or gender was significant, the Bonferroni test was used to make comparisons between means. In order to analyse effect of carcass weight on percentage of main tissues in main cuts, polynomial regression was performed. All statistical analyses were accomplished using the Statsoft Statistica 8.0. In table 1, effects of gender and carcass weight on main tissues of dissected ham in absolute and relative values are presented. It could be seen that gender had a significant effect on fat content, while in terms of meat content, significant effect was only on relative values. Bone content was not influenced by gender. As expected, carcasses from the heaviest weight group had the heaviest hams; although in relative terms the difference between the groups was statistically significant only for the two heaviest weight groups. Regarding the fat tissue, significant differences were not found between the investigated groups except between the heaviest (120 kg) and lightest (170 kg). When observing the meat tissue in relative terms, the lightest group (120 kg) had the higher proportion of lean and was significantly different only from the heaviest (170 kg) weight group (66.860%). The hams from the heaviest group (170 kg) of pig carcasses had significantly higher bone content in absolute terms, comparing to the other groups, but bone percentage for the same group was lowest (8.514) and statistically different from the first four weight groups. In table 2, effects of gender and carcass weight on main tissues of dissected shoulder in absolute and relative values are presented. In the case of dissected shoul- Table 1: Effect of gender and carcass weight on main tissues of dissected ham Trait Gender Weight group Castrates Gilts Sign. 120 kg 130 kg 140 kg 150 kg 160 kg 170 kg Sign. N 50 49 15 17 15 18 17 17 Ham (kg) 15.916 15.701 N.S. 13.646a 13.894* 15.009bc 16.407cd 16.835d 19.060e ** (0.159) (0.163) (0.288) (0.271) (0.305) (0.263) (0.274) (0.271) Ham (%) 27.0521 27.638^ N.S. 27.990a 27.548 27.729 27.606 26.704b 26.493c * (0.137) (0.141) (0.249) (0.234) (0.264) (0.227) (0.237) (0.234) Fat (kg) 3.486x 3.043y * 2.374a 2.765abc 2.929cde 3.273cde 3.613e 4.631f * (0.074) (0.076) (0.134) (0.126) (0.142) (0.122) (0.128) (0.126) Fat (%) 21.7431 19.075y * 17.414* 19.928bc 19.405bc 19.895bc 21.442cd 24.370d * (0.421) (0.432) (0.763) (0.717) (0.808) (0.695) (0.727) (0.717) Meat (kg) 10.918 11.197 N.S. 9.807a 9.813a 10.619* 11.592bc 11.754ce 12.758e * (0.131) (0.135) (0.238) (0.224) (0.252) (0.217) (0.227) (0.224) Meat (%) 68.6871 71.536y * 71.858a 70.576a 70.840 70.706a 69.830 66.860b * (0.405) (0.415) (0.734) (0.689) (0.777) (0.669) (0.699) (0.689) Bones (kg) 1.471x 1.428y N.S. 1.338abd 1.332abd 1.440bc 1.509ce 1.457cd 1.621e * (0.016) (0.016) (0.029) (0.027) (0.031) (0.026) (0.028) (0.027) Bones (%) 9.302 9.172 N.S. 9.819a 9.608a 9.616a 9.200abc 8.665cd 8.514d * (0.081) (0.084) (0.148) (0.139) (0.156) (0.134) (0.141) (0.139) * = P < 0.01; N.S. = no significance 106 Acta agriculturae Slovenica, Supplement 3 - 2012 Table 2: Effect of gender and carcass weight on main tissues of dissected shoulder Trait Gender Weight group Castrates Gilts Sign. 120 kg 130 kg 140 kg 150 kg 160 kg 170 kg Sign. N 50 49 15 17 15 18 17 17 Shoulder (kg) 9.0801 8.745y N.S. 7.195a 8.963bcde 8.402cd 9.059de 9.379e 10.478f * (0.101) (0.104) (0.184) (0.172) (0.194) (0.167) (0.175) (0.172) Shoulder (%) 15.485 15.424 N.S. 14.739a 17.769b 15.506a 15.241a 14.887a 14.585a * (0.119) (0.122) (0.215) (0.202) (0.228) (0.196) (0.205) (0.202) Fat (kg) 2.1401 1.763^ * 1.349a 1.830b 1.902b 1.913b 2.167b 2.549c * (0.049) (0.050) (0.089) (0.083) (0.094) (0.081) (0.085) (0.083) Fat (%) 23.3971 19.934^ * 18.682a 20.328ab 22.551bcf 21.076 23.058be 24.297ef * (0.447) (0.458) (0.810) (0.760) (0.857) (0.738) (0.771) (0.760) Meat (kg) 5.821 5.869 N.S. 4.803a 6.067bde 5.417acd 6.019d 6.060def 6.705bf * (0.076) (0.078) (0.137) (0.129) (0.145) (0.125) (0.131) (0.129) Meat (%) 64.1531 67.224y * 66.741 67.773a 64.532b 66.489 64.610 63.989bc * (0.411) (0.422) (0.745) (0.700) (0.789) (0.679) (0.709) (0.700) Bones (kg) 1.102 1.098 N.S. 1.028a 1.024a 1.073a 1.126 1.142 1.207b * (0.014) (0.015) (0.026) (0.025) (0.028) (0.024) (0.025) (0.025) Bones (%) 12.265 12.667 N.S. 14.348a 11.450b 12.805b 12.419b 12.217b 11.557b * (0.141) (0.145) (0.256) (0.241) (0.271) (0.234) (0.244) (0.241) * = P < 0.01; N.S. = no significance Table 3: Effect of gender and carcass weight on main tissues of dissected loin Trait Gender Weight group Castrates Gilts Sign. 120 kg 130 kg 140 kg 150 kg 160 kg 170 kg Sign. N 50 49 15 17 15 18 17 17 Loin (kg) 10.124x 9.613y N.S 8.013a 8.243ab 8.820bc 10.073cd 11.076d 12.985e * (0.153) (0.157) (0.278) (0.261) (0.294) (0.253) (0.265) (0.261) Loin (%) 17.051 16.770 N.S 16.423a 16.345a 16.211a 16.943 17.533 18.005b * (0.148) (0.152) (0.269) (0.253) (0.285) (0.245) (0.256) (0.253) Fat (kg) 3.139x 2.498y * 1.884a 2.169a 2.370a 2.578a 3.360b 4.550c * (0.084) (0.087) (0.153) (0.144) (0.162) (0.139) (0.146) (0.144) Fat (%) 30.351x 25.153y * 23.417ab 26.171bc 26.383bc 25.415bc 30.095c 35.030d * (0.604) (0.620) (1.095) (1.028) (1.159) (0.997) (1.042) (1.028) Meat (kg) 5.122 5.241 N.S 4.454a 4.433a 4.808abc 5.496cde 5.703de 6.194de * (0.091) (0.094) (0.166) (0.156) (0.175) (0.151) (0.158) (0.156) Meat (%) 50.976x 55.052y * 55.622a 53.785a 54.721a 54.680a 51.659a 47.619b * (0.523) (0.537) (0.948) (0.891) (1.004) (0.864) (0.903) (0.891) Bones (kg) 1.896 1.895 N.S 1.714ac 1.653a 1.769abd 1.974bcde 2.045de 2.216e * (0.031) (0.031) (0.056) (0.052) (0.059) (0.051) (0.053) (0.052) Bones (%) 18.989x 20.043y * 21.454ab 20.160bd 20.155bd 19.654bd 18.517de 17.157e * (0.257) (0.264) (0.467) (0.438) (0.494) (0.425) (0.445) (0.438) * = P < 0.01; N.S. = no significance Table 4: Effect of gender and carcass weight on main tissues of dissected ribs Trait Gender Weight group Castrates Gilts Sign. 120 kg 130 kg 140 kg 150 kg 160 kg 170 kg Sign. N 50 49 15 17 15 18 17 17 Ribs (kg) 11.796 11.381 N.S 9.468a 9.692a 11.214b 11.806b 12.688b 14.662c * (0.156) (0.160) (0.283) (0.265) (0.299) (0.258) (0.269) (0.265) Ribs (%) 20.004 19.846 N.S 19.418* 19.183b 20.634c 19.843 20.110 20.361 * (0.147) (0.151) (0.267) (0.251) (0.283) (0.243) (0.254) (0.251) Fat (kg) 2.494 2.431 N.S 1.488* 1.926bc 2.261cd 2.623d 2.590d 3.886e * (0.071) (0.073) (0.129) (0.121) (0.136) (0.117) (0.123) (0.121) Fat (%) 20.727 20.708 N.S 15.711a 19.547b 20.077b 22.130b 20.343b 26.494c * (0.456) (0.469) (0.828) (0.777) (0.876) (0.754) (0.788) (0.777) Meat (kg) 8.307x 7.885y N.S 7.054ac 6.725a 7.840bcd 8.268d 8.961de 9.728e * (0.111) (0.114) (0.202) (0.189) (0.214) (0.184) (0.192) (0.189) Meat (%) 70.661 69.727 N.S 74.468a 69.697bc 69.915bc 70.030bc 70.659b 66.395c * (0.426) (0.438) (0.773) (0.726) (0.819) (0.704) (0.736) (0.726) Bones (kg) 1.076 1.060 N.S 0.947* 1.003bc 1.080 1.033bc 1.125cd 1.221d * (0.019) (0.019) (0.034) (0.032) (0.036) (0.031) (0.032) (0.032) Bones (%) 9.231 9.536 N.S 10.031abc 10.439b 9.746 8.810ce 8.913ce 8.360e * (0.168) (0.173) (0.305) (0.286) (0.323) (0.278) (0.290) (0.286) * = P < 0.01; N.S. = no significance der, gender had an effect on fat and lean relative content, while no effect was obtained in bone tissue. Carcass weight on the other side had an effect on all observations. Significant differences were found between the investigated groups in shoulder weight as naturally expected. Heaviest group of carcasses (170 kg) had significantly more kilograms of fat in shoulder than other groups, while in relative terms the situation is similar. Regarding the meat percentage, significant differences were found between the heaviest (170 kg) and some of the lighter investigated groups. Dissection of the shoulder resulted with significant effect of carcass weight on bone content, with noticeable descending trend by increase of the carcass weight. The influences of gender and carcass weight on main tissues of dissected loin in absolute and relative values are presented in table 3. Gender showed the effect on relative values of fat, lean and bone content. Like the case of ham and shoulder, carcass weight had an effect on all observed contents. The weight of loin significantly differs among the all carcass weight groups, although differences weren't significant between all groups. Also important to point out, unlike ham and shoulder percentage, loin percentage increases by increase of carcass weight of pigs. Percentage of fat in loin was affected by the carcass weight of slaughtered pigs, and carcasses dif- fer among the groups significantly. In addition, fat percentage in loin area is increasing by the increasing the carcass weight. The values of meat percentage differed significantly between the heaviest (170 kg) and all other groups and the lowest percentage of meat was found in the loins from the heaviest group of pig carcasses. In table 4, gender and carcass weight effects on main tissues of dissected ribs are presented. From the presented data it could be seen that gender did not have an effect on rib main tissue contents. Carcass weight showed effect on all main tissue contents of ribs. The values of weight of this part are significantly increasing by the increase of carcass weight, as well as the percentage of fat. Significantly higher values of meat percentage were found in the ribs of the lightest group than in other groups and therefore, growth pattern could be seen. In absolute and relative terms of bone tissue, values differed between all weight groups of pig carcasses with declining trend when carcass weight increases. In table 5, effect of gender and carcass weight on total values of carcass dissected contents. From these results generally could be confirmed that the growth pattern of carcass cuts weight increases by increasing the carcass weight. Furthermore, gender had an influence on fat and lean percentage values, where castrates had significantly higher fat content and lower lean percentage than gilts. EFFECT OF CARCASS WEIGHT AND GENDER ON MAIN TISSUE DISTRIBUTION IN CARCASS MAIN CUTS Table 5: Effect of gender and carcass weight on total content of main tissues Trait Gender Weight group Castrates Gilts Sign. 120 kg 130 kg 140 kg 150 kg 160 kg 170 kg Sign. N 50 49 15 17 15 18 17 17 FAT (kg) 12.2031 10.516y * 7.807ab 9.234bc 10.215cd 11.288de 12.798de 16.818f * (0.253) (0.260) (0.459) (0.431) (0.486) (0.418) (0.437) (0.431) FAT (%) 20.4361 18.049^ * 15.989ab 18.207bc 18.711c 18.922ac 20.234c 23.393d * (0.347) (0.356) (0.629) (0.590) (0.666) (0.573) (0.599) (0.590) LEAN (kg) 34.042 34.187 N.S 29.475ac 30.270ac 32.467cd 35.527de 36.768e 40.178f * (0.375) (0.385) (0.681) (0.639) (0.720) (0.620) (0.648) (0.639) LEAN (%) 57.8731 60.275^ * 60.487a 60.079a 59.941a 59.805a 58.341 55.791b * (0.358) (0.368) (0.650) (0.610) (0.687) (0.592) (0.618) (0.610) BONE (kg) 6.571 6.460 N.S 5.934a 5.895a 6.205abc 6.691bc 6.881cde 7.488e * (0.076) (0.078) (0.138) (0.129) (0.146) (0.125) (0.131) (0.129) BONE (%) 11.214 11.444 N.S 12.186ab 11.719bc 11.477 11.274cd 10.922cde 10.397e * (0.105) (0.108) (0.191) (0.179) (0.202) (0.174) (0.182) (0.179) * = P < 0.01; N.S. = no significance This could be explained by the effect of male castration, since castrates usually have higher fat content. In the study of Beattie et.al. (1999), gilts had higher fat content, but they compared it with boar carcasses. Gender had no effect on bone content. Carcass weight showed influence on all dissected tissues. The same growth is found in many other studies about the growth of tissues (Kusec et.al. 2010: Gu et al., 1992; Davies and Kallweit, 1979). In terms of relative values of fat content, growth is present by increase of carcass weight. Contrary to fat content, percentage of meat content in carcasses decreases by increase of carcass weight. In the study of Kusec et.al. (2010) and Valis et al. (2008) the same declining trend of meat content was found. Observing the relative values of bone content, declining trend could be found with significant differences between the lightest and heaviest group. In figure 1 is shown the effect of carcass weight on total percentage of fat, meat and bone tissue in carcass obtained by polynomial regression. As stated above, this pattern confirms the excepted fact that by increase of carcass weight, percentage of fat tissue increases while the percentage of meat and bone tissues decreases. 70 60 SO Ž 40 S TO J| U) * 30 H g 20 10 pO O oo o o o ° o ®>c o % Ot>0 M ^ O ^ a> O carcass weight (kg). total share of lean(%); y = 69 4676-0.1786"*: r= -0.4949. p = 9.00000: r- - o :jsj "a. icital share ot 1st (W) ' E>.. iotal share of lean (%} "A Iotal share of hone {%) carcass weight (kg): total share of fat (%): y = 4.3811 ♦ 0.2565-it; r = 0.6450, p = 0.0000; rMmw afc- D oc O n n ° a u □ na IB- -Dû-, «■-Si □ -Tl carcass weigtit (kg): total snare of Bone (%): y ■ 15 2573 - 0.0662'x; r = -0 6630, p « 0.0000. r>-