Naslov
Growth pattern of hybrid pigs as influenced by mhs- genotype and feeding regime

Autori
Kušec, Goran

Vrsta, podvrsta i kategorija rada
Ocjenski radovi, doktorska disertacija

Fakultet
Faculty of Agricultural Sciences

Mjesto
Göttingen, Njemačka

Datum
22.11

Godina
2001

Stranica
74

Mentor
Glodek, Peter

Neposredni voditelj
Kallweit, Erhard

Ključne riječi
pig ; growth ; genotype ; feeding ; Magnetic Resonance Imaging

Sažetak
A total of 72 castrated males divided in 4 groups, according to genotype (MHS-gene carrier, Nn and MHS negative, NN) and feeding regime (standard and intensive) were included in this experiment. All pigs were 4 line crossbreeds (Pi x Ha sire x LW x GL dam). The data on muscle tissue and fat volumes were obtained by MR-imaging. The MR-imaging was performed at 4 week intervals, starting at the age of 10 weeks up to the final live weight of approximately 120 kg. At the age of 26 weeks all the pigs were slaughtered ; important carcass traits and meat quality indicators were measured. The volumes of lean and fat were calculated using the Cavalieri method. An allometric analysis was performed for description of differential growth ; for modelling the growth dynamics, the asymmetric S-function was used. During the experiment 3 Nn pigs (2 from intensive, 1 from standard group) and 1 NN pig from the standard group died. The following results were obtained: 1. In the intensive group, NN pigs had significantly higher average daily feed intakes and higher intake/muscle gain ratios (p<0.05) than carriers (Nn) ; in the standard group, NN pigs had higher average daily gains (p<0.05). It can be stated that Nn pigs perform better in the intensive feeding regime, while NN pigs are more suitable for restricted feeding systems. 2. The meat quality of NN pigs was better than the meat quality of Nn carriers. Since carcass traits of the investigated pigs were found to be unaffected by genotype, there is no apparent reason for using the MHS-gene in fattening or breeding of modern hybrid fattening pigs. 3. There were no significant differences in the allometric growth coefficients between pig genotypes from both feeding regimes. The feeding group, however, influenced the growth of fat, since there was a significant difference (p<0.05) found between feeding groups in the allometric growth coefficient. 4. The live weight growth of pigs from two feeding regimes had different patterns. Asymptotic final weight (A) for the intensive group of pigs was 220 kg ; coefficient of determination R2 was 0.99961 ; asymptotic final weight (A) for the standard group of pigs was 160 kg, R2=0.99935. The intensive stage of growth for intensively fed pigs lasted 138 days (139.13 days for NN ; 136.35 days for Nn pigs). For the standard group of pigs the intensive stage of growth lasted about 116 days (114.51 days for NN ; 118.47 days for Nn pigs). 5. The asymmetric S- function enabled a good prediction of the live weight of pigs based upon initial condition (first weighing). The prediction was accurate (the difference between predicted and real time was within one week) in 88.24 % of the pigs in the intensive group and 79.41% of the cases in the standard group of pigs. 6. The stage of intensive muscle growth was approximately equal for both feeding groups ; 110.48 and 114 days in the intensive and standard group, respectively (difference about 3.5 days). The optimal slaughter weights, in sense of a maximal utilisation of muscle growth potential, calculated by means of asymmetric S- function for live weight and muscle volume were: 126 kg (164 days) and 112 kg (167 days) for pigs from the intensive and standard group, respectively. 7. No obvious difference was observed in the pattern of muscle growth between MHS-genotypes of pigs within different feeding regimes. Important stages of muscle growth were reached by both genotypes within the same week. 8. The feeding regime had more influence on the growth of lean muscle in Nn than in NN pigs. The stage of intensive growth of muscle tissue for Nn pigs from the intensive group lasted 9.88 days shorter than for the same genotype of pigs kept under the standard feeding regime. The difference in the duration of intensive stage of muscle growth between NN pigs from two feeding regimes was 1.96 days. This indicates that the standard feeding regime does not support full utilisation of the genetic potential for muscle growth of Nn pigs. 9. The growth of fat was influenced solely by feeding regime. Analysis of fat growth by asymmetric S-function confirmed the late- maturing nature of fat also found by allometric analysis (fat-to-live weight relationship). The patterns of fat growth of both pig genotypes within two different feeding systems were almost identical. 10. In general, homozygous negative pigs performed better under the conditions of a more cost effective standard feeding regime and they had better meat quality than MHS-gene carriers, which leads to the conclusion that there is no good reason for using carrier pigs as hybrid fattening pigs any longer.

Izvorni jezik
Engleski

Znanstvena područja
Poljoprivreda (agronomija)

POVEZANOST RADA