Acta agriculturae Slovenica, suplement 2 (september 2008), 53–58. 16th Int. Symp. “Animal Science Days”, Strunjan, Slovenia, Sept. 17–19, 2008. Agris category codes: L10 COBISS Code 1.08 CHARACTERISTICS OF CARCASS AND TISSUES IN PIGS OF TUROPOLJE BREED AND CROSSBREDS TCSL Marija ĐIKIĆ a), Krešimir SALAJPAL a), Danijel KAROLYI a), Domagoj Đikić b) and Mirjana MIHELČIĆa) a) Univ. of Zagreb, Fac. of Agriculture, Dept. of Animal Science, Svetošimunska c. 25, HR-10000 Zagreb, Croatia, e-mail: mdikic@agr.hr b) Univ. of Zagreb, Fac. of Science, Dept. of Animal Physiology, Rooseweltov trg 6, HR-10000 Zagreb, Croatia ABSTRACT Some carcass traits and muscle fiber characteristics of m. Longissimus dorsi (MLD) in pigs of Turopolje breed (T) and crossbreds TCSL were analyzed. The hogs T (n = 19, 568 ± 20 days) and TCSL (n = 10, 575 ± 27 days) were progenies of the same boar, T3HB, and sows of Turopolje breed and crossbred CSL (♂C Hypor line × ♀SL, Swedish Landrace). All pigs were reared and fattened in the outdoor system, according to traditional Croatian technology of low input. Live (LW) and carcass weight (CW) and some carcass traits and chemical composition of muscle and fat tissues were analyzed. In the carcass, the lean percentage (L%) was calculated on the basis of back fat thickness (BF) and MLD thickness, according to “two point” method (CRO, Regulation, NN 85/05). The samples of MLD from the left side at the 13/14th rib level were taken after slaughtering (5 min.) and frozen in liquid nitrogen until histo-morphological analysis (diameter of slow twitch oxidative, SO; fast twitch glycolytic, FG; and fast twitch oxidative, FOG fiber types). After chilling carcass (24 h, at + 4 ºC), the samples of MLD and the belonging back fat were taken from the same place for analysis of chemical composition (water W, protein P, lipid L, ash A). According to the estimated results the pigs of Turopolje breed and TCSL significantly differed as follows: LW (95.31 and 117.10 kg), CW (77.11 and 97.50 kg), BF (31.68 and 28.00 mm), MLD dept (50.16 and 60.10 mm), L (45.25 and 47.69%), SO (33.69 and 44.24 µm), and FG (38.48 and 47.60 µm). The chemical content of muscle and fat tissues was not significantly different between investigated pigs. Key words: pigs / breeds / Turopolje pig / TCSL crossbreds / carcass / m. longissimus dorsi LASTNOSTI KLAVNIH POLOVIC IN TKIV PRI TUROPOLJSKEM PRAŠIČU IN TCSL KRIŽANCIH IZVLEČEK Analizirali smo nekatere lastnosti klavnih polovic in lastnosti mišičnih vlaken v m. longissimus dorsi (MLD) pri turopoljskih prašičih (T) in TCSL križancih. Merjasci T (n = 19, 568 ± 20 dni) in TCSL (n = 10, 575 ± 27 dni) so bili potomci istega merjasca, T3HB in svinj turopoljske pasme in križancev CSL (♂C Hypor linija × ♀SL, švedska landrace). Prašiči so bili vzrejeni in spitani zunaj v prosti reji v skladu s tradicionalno hrvaško tehnologijo majhnega inputa. Analizirali smo telesno maso in maso klavnih polovic ter nekatere lastnosti klavnih polovic in kemično sestavo mišičnega in maščobnega tkiva. V klavnih polovicah smo delež pustega mesa izračunali na osnovi debeline hrbtne slanine in MLD po dvo-točkovni metodi (CRO, Pravilnik NN 85/05). Vzorce leve MLD med 13. in 14. rebrom smo odvzeli po klanju (5 minut), jih zamrznili v tekočem dušiku za čas do histomorfoloških analiz (premer počasi krčljivih oksidativnih, SO; hitro krčljivih glikolitični, FG; in hitro krčljivih oksidativnih FOG tipov mišičnih vlaken). Po ohlajanju polovic (14 ur pri + 4 ºC) smo vzorce MLD in pripadajoče hrbtne slanine odvzeli na istem mestu in določili kemično sestavo (voda, beljakovine, maščobe, pepel). Po ocenjenih rezultatih se turopoljski prašiči in križanci TCSL pomembno razlikujejo v sledečih lastnostih: http://aas.bf.uni-lj.si Acta agriculturae Slovenica, suplement 2 (september 2008). 54 telesna masa (95,31 oz. 117, 10 kg), masa klavnih polovic (77, 11 oz. 97,50 kg), debelina hrbtne slanine (31,68 oz. 28,00 mm), debelina MLD (50,16 oz. 60,10 mm), delež mesa (45,25 oz. 47,69 %), premer SO mišičnih vlaken (33,69 oz. 44,24 µm) in premer FG mišičnih vlaken (38,48 oz. 46,60 µm). Kemična sestava mišičnega in maščobnega tkiva se ni pomembno razlikovala med preiskovanima pasmama prašičev. Ključne besede: prašiči / pasme / turopoljski prašič / križanci TCSL / klavne polovice / m. longissimus dorsi INTRODUCTION Turopolje pig breed is the autochthonous Croatian breed and one of older Europeans pigs and breeds (Ritzoffy, 1931; Belić et al., 1961; Robić et al., 1996). Turopolje pig/breed was created as and today it still is a breed for the outdoor system of production in ecosystem of flood forests (Quercus robour, Fraxinus excelsior, Fagus silvatica) and marsh meadows (Deschampsietum caespitosae), continental climate and technologies of low input in outdoor system. In the past and today (in some area and in cases) an old Croatian pig breeding and production is used in the outdoor system. This technology is characterized with low feed input, with the possibility of utilization of natural resources of the environment (acorn, grass and soil). The numbers of scientific and expert papers were published (Đikić et al., 2002) about origin, historical and economic importance and factors which brought this breed into FAO list of endangered and disappearing breeds (Loftus and Scherf, 1993). This list was formed after signing the Convention on Biological Diversity (CBD) in Rio de Janeiro in June 1992. Republic of Croatia signed CBD (January 5th, 1997). In 1999 Croatia passes the strategy of flora and fauna biological diversity which includes Turopolje pig (Radović, 1999). Table 1 show the size of breeding population registered in herdbook of Turopolje pig breed in years 1996 (the start of program of re- establishment and preservation) and in 2007 by annually reports of Croatian Livestock Center (CLC, 1997 and 2008). Table 1. Breeding population of Turopolje pig breed in Croatia (Croatian Livestock Center, 1997; 2008) Year Sows Boars Gilt Young boar 1996 12 3 -- -- 2007 164 29 2 2 Number of sows and boars (Table 1) besides the state subsidies indicate the state of endangerment and disappearing of this breed (FAO standards, Loftus and Scherf, 1993). In the last ten years the renewed was very slow, but and the number of gilts gives no opportunity to change the present state. The breeding population is owned by few family farms and by organization Universitas Communitas Nobilium Campi Turopolia (UCNCT, V. Gorica) which owns the majority of the population. In 1996 UCNCT started first with preservation by opening herd book at Croatian Livestock Center (CLC). Some of the reasons of very slow increase of breeding population could be in breed traits (small litter size and index farrowing /sow /year, low daily gain of piglets and hogs), appearance of some diseases (brucellosis) or lack of land areas – what are needs at preservations in situ in outdoor system. Also, there is no economic program for meat production or dry meat products, nor breed is used in crossbreeding with modern genotypes of pigs as it is usual with native breeds in Italy or Spain (Oliver et al., 1997). However, it is important to emphasize that Turopolje pig breed traditional production system of low input in the outdoor ecosystem of flood forests and marsh meadows, is a part of Croatian and World wide biological diversity and cultural heritage, and therefore needs to be preserved. With this reason, Đikić M. et al. Characteristics of carcass and tissues in pigs of Turopolje breed and crossbreds TCSL. 55 the remainder of Turopolje pig population is under research of many biological traits, both on phenotypic and molecular level (Đikić et al., 2002; Harcet et al., 2006; Margeta et al., 2006). The objective of this study was to establish some characteristics of carcass traits and chemical composition of muscle and fat tissues as well as muscle fiber diameter at Turopolje pig and their crossbreds TCSL. Results of this research will be used as a base for defining the standards of today Turopolje pig breed, as well as a starting point for breeding and economical program in crossing with some modern genotype of pig. MATERIAL AND METHODS Animals and management Investigation was carried out on hogs of Turopolje breed (T, n = 19, 568 ± 20 age days) and crossbred TCSL (n = 10, 575 ± 27 age days). The hogs were progeny of same boar of Turopolje breed T3HB and two groups of sows, Turopolje breed and crossbred CL (♂C Hypor line × ♀SL Swedish Landrace). Pigs were reared and fattened in the outdoor production system of flood forest biocenosis (Quercus robur, Fraxinus excelsior and Fagus sylvatica) and marsh meadows (Deschampsietum caespitosae) in the Turopolje area (near to Zagreb). Traditional Croatian technology of low feed input (0.5 kg of corn seed/animal/day) in the ecosystem was implemented in the extensive management. Natural resources (acorn, soil and pasture) were utilized, but having a mind the environmental balance as well. Carcass and tissues characteristics In the abattoir for each hog were established the live weights, and hot carcass after slaughtering. In the carcass the lean percentage (L%) was calculated on the basis of back fat thickness, (BF, mm) measured on the spot where m. gluteus medius gets the deepest in the subcutaneous fat. The MLD (mm) thickness was measured as the shortest distance between the cranial end of m. gluteus medius and dorsal spinal edge and the method “two point”, (TP, CRO Regulation/Pravilnik, NN, 85/05) was used. For the chemical analysis the samples of muscle and fat tissues were taken from the MLD and belonging back fat (between 13/14th ribs) on left side after chilling (24 h at + 4 ºC). The standard methods were used (ISO 1443/73, NN, 39/99) for chemical analysis. In samples of muscle and fat tissues the percentage of water (W, drying method at temperature of 105 ºC to constant mass), protein (P, total proteins per Kjeldahl), lipid (L, extraction with ether per Soxlhet) and ash (A, direct burning at temperature at 550 ºC) were determined. Muscle fiber characteristics were determined in the sample of the MLD taken on dorsal side in the 13/14th rib level 5 min after slaughtering and frozen in liquid nitrogen until analysis. For muscle fiber typing (Salomon, 1981; Pearse, 1972), 10 µm thick transverse serial sections were cut in cryostat (Frigocut 2800, Reichert–Jung, Heidelberg, Germany) and stained for actomyosin ATP-ase after pre-incubation in alkaline (pH 9.4), and acid (pH 4.33 and 4.6) media in order to identify three main fiber types (slow twitch oxidative, SO; fast twitch glycolityc, FG and fast twitch oxidative-glycolityc, FOG). In addition, serial sections were used to demonstrate SDH and NADH reductase activity. The fiber diameter (µm) was calculated from fiber cross section area assuming fiber were circular in shape. The data were analyzed by software package SAS (vs. 6.10, 1999). The t-test was used in data analyses. Acta agriculturae Slovenica, suplement 2 (september 2008). 56 RESULTS AND DISSCUSION Carcass characteristics The results in Table 2 show live and carcass weights and some technologies characteristics of carcass of Turopolje pig breed and crossbreds TCSL. Table 2. Live weight and carcass characteristics of Turopolje (T) and crossbred (TCSL) pigs Turopolje (T) Crossbred (TCSL) Traits ± SD Live weight, kg 95.31 ± 2.45 ** 117.1 ± 4.19 ** Carcass (w), kg 77.11 ± 2.22 ** 95.60 ± 4.54 ** Back fat, mm 31.68 ± 0.81 ** 28.00 ± 1.79 ** MLD, mm 50.16 ± 1.32 ** 60.10 ± 1.67 ** Lean, % 45.25 ± 0.22 ** 47.69 ± 0.65 ** SEUROP class R R ** P < 0.01 The estimated results of T breed and crossbred TCSL (Table 2) pigs of the slaughtering and hot carcass weights, and in the relation of pig’s age, indicate on very low life daily gain. But the slaughter weights at TCSL were higher than in T and life daily gain was higher of about twenty percent. The carcass lean percentage was different between groups; however the carcasses of both groups were classified in R class according to SEUROP system. By Croatian Regulation (NN, 85/05) in class R the lean percentage is in range from 45% to 50% and therefore the carcasses of T were in the lowest and TCSL in the middle of R class. The differences between T and TCSL pigs in lean percentage were the consequence of differences in thickness of back fat and MLD what a base in carcasses classification is. The estimated meatiness (Table 2) between pigs of T breed and TCLS were significantly different (P < 0.01), as expected due to their different genetic background. Turopolje pig breed is a late mature fatty/meaty production type of pig and was not under the selection processes as modern meaty type of sows CSL used in crossing at production of crossbred’ TCSL. But, differences between and variability (some traits as live/carcass weights) within groups could be consequence in different feed utilization and to acclimatization of animals in the conditions of technology of low feed input and outdoor production system. The results of crossbred TCSL give opportunity to use Turopolje pig breed in crossing with modern pig breeds and setting up a breeding program that would support the increase of population on the economic base. Tissues composition The chemical composition of MLD and back fat is shown in Table 3. Chemical composition of MLD and back fat (Table 3) was not significantly different between groups. In muscle tissue of both groups the content of lipid was low and water was high. The given results for lipid and proteins are different in comparisons with standard values for adult mammals (water 75%, lipid 2%, and protein 19%) by Lawrie (1998). In the muscle tissue of investigated pigs the content of water was higher and content of lipid was lower than in some native breed like Mangalitsa (fatty), Black Slavonian and Iberian (meaty/fatty) or in some modern selected breeds and crossbreds (Oliver et al., 1997; Kralik et al., 2001; Kallweit et al., 2001). The same values of fat tissue were in opposite than in muscle tissues in comparison to results by according literature. These indicate the specific way of the Đikić M. et al. Characteristics of carcass and tissues in pigs of Turopolje breed and crossbreds TCSL. 57 metabolism and storage of fat in the body and could be one of the reasons of higher thickness of back fat in Turopolje breed in comparison to other breeds. Also, these results indicate the need of further investigations of other traits and tissue characteristics (iodine number, collagen content etc). Table 3. Chemical composition of MLD and back fat (%) of Turopolje (T) and crossbred (TCSL) pigs Turopolje (T) Crossbred (TCSL) Content, % Tissue x ± SD M 75.31 ± 0.33 75.84 ± 0.34 Water F 8.20 ± 0.54 8.53 ± 1.02 M 21.05 ± 0.25 20.53 ± 0.25 Protein F 1.73 ± 0.15 1.74 ± 0.30 M 1.01 ± 0.07 1.30 ± 0.13 Lipid F 89.43 ± 0.69 89.53 ± 1.22 M 1.05 ± 0.01 1.05 ± 0.02 Ash F 0.09 ± 0.86 × 10–3 0.08 ± 0.89 × 10–3 M 1.58 ± 0.17 1.28 ± 0.16 NFE * F 0.55 ± 0.2 × 10–3 0.11 ± 0.1 × 10–3 * Nitrogen-Free Extract; M = muscle Longissimus dorsi; F = back fat Results in the Table 4 show the diameters of SO, FG and FOG fibers types of MLD of T and crossbreds TCSL pigs. Table 4. Histo-morphological characteristics of muscle fiber types in MLD of Turopolje (T) and crossbred (TCSL) pigs SO FG FOG Breed/ crossbred x ± SD, µm Turopolje 33.69 ± 2.22 * 38.48 ± 2.02 ** 36.84 ± 2.58 TCSL 44.24 ± 4.34 * 47.60 ± 2.89 ** 38.99 ± 1.10 ** P < 0.01; * P < 0.05 In investigated pigs the fiber diameters of SO, FG and FOG showed, beside some higher variability, that values were in a normal range in comparison to general reports for the swine as species by Lawrie (1998). However, the diameters of fiber types SO, and FG were significantly smaller in T pig breed than in crossbred TCSL pigs. However, comparison with literature results showed that the diameters of all fiber types were smaller than in the selected pigs with high growth potential and lean deposition in the carcass (Maltin et al., 1997; Karlson et al., 1999; Fiedler et al., 2003). These results are some different in consideration with values for adult pigs (wild 58–85 µm and domestic 40–80 µm) cited by Pas et al. (2004)of many authors. That indicated that Turopolje pig breed could be genetically different in the relation to other breeds, especially if keep in mind its origin (Ritzoffy, 1931) and absent of intensive selection for muscle growth which in pigs may cause a large changes in fiber type composition (Maltin et al., 1997). Investigation of fiber types proportions should be continued and especially in the relation to the quality traits of meat. Acta agriculturae Slovenica, suplement 2 (september 2008). 58 CONCLUSIONS Turopolje pig breed is in the state of endangerment (by FAO standard) and the present number of gilts suggests that fast changes in the number of animals are not possible. In present population of Turopolje pig breed some characteristics of carcass and tissue are specific and could be a consequence of historical conditions of breeding, selection and production of this breed in the specific environment of the outdoor system. 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