Influence on intramuscular fat content of pork

The aim of the study presented was to investigate, how far supplying fattening pigs deficiently with limiting amino acids can increase the intramuscular fat, and what kind of consequences have to be expected regarding fattening performance, carcass composition and further meat quality traits. In total 45 male castrates and 49 females (Pietrain-NN(star)German Landrace) were randomized to 4 feeding groups: The control group (1) got a diet with demand-oriented contents of amino acids. The other 3 groups were fed in the final fattening phase (starting from about 70 kg live weight) with diets containing insufficient proportions (60% of demand) of lysine (group 11), methionine + cystine (group 111) or lysine + methionine + cystine (group IV). In general considerable changes only showed up in those two groups (11 and IV) provided inadequately with lysine. This conclusion regards in particular group II. Animals of this treatment consumed about 0.4 kg more feed per kg live weight gain than the control pigs, whereas the daily gain decreased - not significantly - by 60 g. Carcasses were fatter, so that the lean content were reduced by 2.5 percentage points. The chemical-physical meat quality traits such as pH value, electrical conductivity and water-holding capacity did not change. The intramuscular fat content showing at two different points of the M. longissimus dorsi and at the A semimembranosus values of 1.2, 1.4 and 2.7%, respectively in the control group, increased only due to the lysine deficit to 2.0, 2.2 and 3.7%, respectively. Moreover in the intramuscular fat the proportion of monounsaturated fatty acids rose significantly at the expense of the polyunsaturated fatty acids. The described effects however only tended to result in improvements of the sensory evaluation and the instrumentally measured tenderness.