Effects of on-farm diets for organic pig production on performance and carcass quality.

An experiment was conducted to evaluate the effects of a restriction to home-grown feedstuffs and abstinence from supplementation with synthetic amino acids (AA), as ideal objectives in organic pig production according to the IFOAM standards, on growth performance and carcass characteristics. One hundred individually housed pigs were allocated to four dietary treatments and fed from growing through finishing to compare three organic barley/wheat-based diets with an isocaloric conventional diet supplemented with synthetic AA. Protein sources in the organic treatments were either faba beans, supplemented with potato protein to the same AA level as the control diet, peas and lupines, or faba beans and lupines, both without further supplementation, leading to a lower level of limited AA. Supplementation of organic diets with potato protein resulted in the same performance as supplementing the conventional diet with synthetic AA, although crude protein levels differed markedly. Pigs fed the organic diets without AA supplementation grew more slowly (P < .05) and had a decreased feed intake in the grower period (P < .05) but nearly the same feed efficiency (P > .05) as pigs fed conventional or organic diets with AA supplementation. Carcass characteristics differed in percentage of lean meat and longissimus area, being lower in the treatments without AA supplementation (P < .05). However, the intramuscular fat was higher without AA supplementation (2.9% fat) than with supplementation (1.2% fat) (P < .01). The data show that the exclusion of AA supplementation resulted in a reduction in pig performance but in an increase in intramuscular fat content; the latter is an important aspect of eating quality characteristics.