# Full Replacement of Soybean Meal with Soybean Press Cake in Diets of Pigs Intended for Long-Cured Dry Ham Production

## TL;DR

Researchers found that replacing soybean meal with soybean press cake in pig diets doesn't harm growth or ham quality and improves fat composition.

## Contribution

This study demonstrates that soybean press cake can fully replace soybean meal in pig diets for long-cured dry ham production without negative effects.

## Key findings

- Pigs fed soybean press cake had higher polyunsaturated fatty acids in fat, improving nutritional value.
- No negative effects on growth, carcass traits, or ham quality were observed with soybean press cake diets.
- Increased linoleic acid levels in press cake-fed pigs met nutritional recommendations favoring unsaturated fats.

## Abstract

Soybean cake, produced by mechanical extraction, may represent a sustainable and novel alternative ingredient to the conventional solvent-extracted meal in pig diets. This study evaluated whether soybean press cake can fully replace soybean meal in the diets of heavy pigs used to produce traditional Italian long-cured dry hams. Eighty pigs were fed either a conventional diet or a diet in which soybean press cake completely replaced soybean meal, and their growth, carcass characteristics, and meat and ham quality were assessed. The results showed no negative effects on animal growth or on the quality of the thighs and the dry-cured hams. Pigs fed soybean press cake showed changes in fat composition, including a reduction in saturated fatty acids and an increase in polyunsaturated fatty acids, which is positive from a human nutrition standpoint. Overall, the findings indicate that soybean press cake can be used in feeding heavy pigs at amounts above the limits currently allowed for the production of traditional cured hams.

The study investigated whether the full replacement of chemically solvent-extracted soybean meal (SM) with mechanically extracted soybean press cake (SC) could be carried out in pigs intended for dry-cured ham production. Eighty Italian heavy pigs were fattened and finished up to a body weight of 165 kg, with half being fed a commercial diet containing SM and the other half fed an isoenergetic and isonitrogenous diet in which SC fully replaced SM. Growth parameters, carcass traits, fresh meat and cured ham quality, and fatty acid composition were analyzed. Thighs were processed according to the Parma ham production rules, which require a long curing period. The only noteworthy differences observed concerned an increase in polyunsaturated fatty acid levels in the subcutaneous fat of the SC group compared with the SM group (17.26 vs. 14.58%, p < 0.05, in fresh thighs and 15.83 vs. 12.14%, p < 0.01, in cured hams), and particularly in linoleic acid (14.85 vs. 13.01%, p < 0.01 in fresh thighs and 13.72 vs. 10.64%, p < 0.01 in cured hams), which is consistent with general nutritional recommendations favoring unsaturated over saturated fatty acids. These modifications did not affect the final quality, oxidative stability, or visual appearance of the long-cured hams. In conclusion, soybean cake–based diets can be applied throughout the production cycle of heavy pigs; however, higher inclusion levels should be carefully managed, as they may affect parameters related to suitability for dry curing.