Die Bodenkultur - Journal for Land Management, Food and Environment


Effects of reduced protein content on performance and N-excretion in pig fattening


An experiment was conducted to evaluate the effects of different protein contents in diets for fattening pigs. Effects on fattening performance, carcass yield, meat quality, composition of fat and N-excreation were investigated.

The experiment was conducted at a test station using five groups with 80 pigs total. They were fattened from 30 to 110 kg live weight. Diet 1 (control diet) and diet 3 were formulated to contain 17.5 % crude protein (CP). In diet 2 CP content was increased to 21 %. Diets 4 and 5 contained 14 % CP. In diet 4 L-lysine, DL-methionine and L-tryptophane were added to reach equal content of essential amino acids compared to diet 1. No amino acids were supplemented in diet 5. In diets 3,4 and 5 soybean meal was substituted partly by 14 % rapeseed expeller.

In this experiment it was shown that the reduction of protein content (with supplementation of amino acids) in rations of fattening pigs did not affect fattening and slaughtering performance and resulted in lower N-excretion.

Because of the worse carcass quality (due to higher fat content) of pigs fed with diet 5, the use of rations with a low protein content without supplementation of synthetic amino acids is not recommended. On the other hand the protein content should not be increased due to the higher N-excretion.

Key words: pig fattening, protein, N-excretion.