## 3 Results and Discussion
\begin{table}
\begin{tabular}{l c c c} \hline \hline \multirow{2}{*}{**Genetic Groups of Fatteners**} & \multicolumn{3}{c}{**Muscle Fibre Type Percentages**} \\ \cline{2-4}  & **IIB** & **IIA** & **I** \\  & \(\mathbf{\bar{x}\pm SD}\) & \(\mathbf{\bar{x}\pm SD}\) & \(\mathbf{\bar{x}\pm SD}\) \\ \hline \multicolumn{4}{c}{Breed} \\ \hline ZS & 64.71 \({}^{\mathrm{a}}\)\(\pm\) 5.97 & 52.58 \({}^{\mathrm{a}}\)\(\pm\) 4.08 & 57.11 \({}^{\mathrm{a}}\)\(\pm\) 4.54 \\ ZS \(\times\) D & 59.99 \({}^{\mathrm{b,c}}\)\(\pm\) 2.21 & 52.78 \({}^{\mathrm{a}}\)\(\pm\) 4.28 & 50.51 \({}^{\mathrm{b}}\)\(\pm\) 2.31 \\ (ZS \(\times\) ZS) \(\times\) D & 61.76 \({}^{\mathrm{a}}\)\(\pm\) 3.46 & 49.96 \({}^{\mathrm{a,c}}\)\(\pm\) 2.72 & 56.49 \({}^{\mathrm{a}}\)\(\pm\) 4.79 \\ ZS \(\times\) PLW & 57.22 \({}^{\mathrm{c}}\)\(\pm\) 3.49 & 48.09 \({}^{\mathrm{b,c}}\)\(\pm\) 2.20 & 52.56 \({}^{\mathrm{b}}\)\(\pm\) 1.90 \\ \(p\)-value & 0.007 & 0.0000 & 0.0001 \\ \hline \multicolumn{4}{c}{Barrows} \\ \hline ZS & 66.62 \({}^{\mathrm{a}}\)\(\pm\) 5.43 & 52.78 \({}^{\mathrm{a}}\)\(\pm\) 4.28 & 57.42 \({}^{\mathrm{a}}\)\(\pm\) 4.66 \\ ZS \(\times\) D & 60.36 \({}^{\mathrm{b}}\)\(\pm\) 1.41 & 46.96 \({}^{\mathrm{b}}\)\(\pm\) 2.07 & 50.71 \({}^{\mathrm{b}}\)\(\pm\) 1.63 \\ (ZS \(\times\) ZS) \(\times\) D & 61.27 \({}^{\mathrm{a,b}}\)\(\pm\) 4.28 & 49.34 \({}^{\mathrm{a,b}}\)\(\pm\) 1.44 & 55.22 \({}^{\mathrm{a,b}}\)\(\pm\) 5.20 \\ ZS \(\times\) PLW & 56.26 \({}^{\mathrm{b}}\)\(\pm\) 4.47 & 47.06 \({}^{\mathrm{b}}\)\(\pm\) 2.43 & 52.71 \({}^{\mathrm{a,b}}\)\(\pm\) 2.36 \\ \(p\)-value & 0.0001 & 0.004 & 0.032 \\ \hline \multicolumn{4}{c}{Gilts} \\ \hline ZS & 62.79 \(\pm\) 6.13 & 52.38 \({}^{\mathrm{a}}\)\(\pm\) 4.09 & 56.78 \({}^{\mathrm{a,b}}\)\(\pm\) 4.64 \\ ZS \(\times\) D & 59.61 \(\pm\) 2.94 & 44.17 \({}^{\mathrm{b}}\)\(\pm\) 2.05 & 50.32 \({}^{\mathrm{c}}\)\(\pm\) 3.04 \\ (ZS \(\times\) ZS) \(\times\) D & 62.25 \(\pm\) 2.85 & 50.57 \({}^{\mathrm{a}}\)\(\pm\) 3.70 & 57.56 \({}^{\mathrm{a}}\)\(\pm\) 4.54 \\ ZS \(\times\) PLW & 58.19 \(\pm\) 2.25 & 49.11 \({}^{\mathrm{a}}\)\(\pm\) 1.54 & 52.41 \({}^{\mathrm{b,c}}\)\(\pm\) 1.60 \\ \(p\)-value & 0.863 & 0.0000 & 0.0001 \\ \hline \multicolumn{4}{c}{Average for genetic groups and sex} & 62.12 \(\pm\) 6.25 & 19.69 \(\pm\) 3.13 & 18.27 \(\pm\) 4.74 \\ \hline \multicolumn{4}{c}{x \(\pm\) SD—mean and standard deviation, mean values in the same columns designated by the different letters differ significantly at: \({}^{\mathrm{a,b,c}}\)\(-\)\(p\)\(\leq\) 0.05, ZS—Zlotnicka Spotted \(\times\) Zlotnicka Spotted; ZS \(\times\) D—Zlotnicka Spotted \(\times\) D—Zlotnicka Spotted \(\times\) Zlotnicka Spotted \(\times\) Zlotnicka Spotted \(\times\) D—Zlotnicka Spotted \(\times\) PLW—Zlotnicka Spotted \(\times\) Polish Large White.} \\ \hline \end{tabular}
\end{table} 
Table 3: Effect of breed or crossing of fatteners on muscle fibre type size (\(\O\)\(\upmu\)m) of \(m\). _longissimus thoracis_. was higher and that of type IIB fibres lower than that of Landrace pigs. [PERSON] and [PERSON] [28], who investigated the muscles of Hampshire, Landrace and Yorkshire pigs, found that the muscles of Hampshire pigs were more oxidative compared to those of the others pigs, and showed that variations in muscle fibre composition in pigs within the breeds were larger than the average variations between the breeds. Muscle fibre composition is influenced by age/body weight and the growth rate of animals [33; 56; 57]. Many researchers have examined the relationship between muscle fibre type characteristics and meat quality [58; 59; 60; 51]. [PERSON] [51] conducted experiments on pigs of the Zlotnicka Spotted and the Pietrain breeds as well as their hybrids and found that smaller proportions of muscles of fast glycolytic character (IIB fibres) were associated with more advantageous meat quality features.