# Nutritional Solution for the Italian Heavy Pig Production to Improve Nitrogen Efficiency While Maintaining Productive Performance and Meat Quality

## TL;DR

This study shows that changing pig diets can reduce nitrogen waste without harming meat quality or productivity in heavy pig farming.

## Contribution

A new low-crude-protein diet significantly improves nitrogen efficiency in heavy pigs while maintaining meat quality and performance.

## Key findings

- A cereal-based low-crude-protein diet reduced nitrogen excretion by 28%.
- Meat quality and productivity remained unchanged with the new diet.
- Nitrogen efficiency improved by 21% with the cereal-based diet.

## Abstract

In Italy, pig farming is mainly based on the production of Protected Designation of Origin (PDO) heavy pigs for cured ham. The aim of our study was to demonstrate new rationing models, in accordance with stringent PDO feed regulations, that achieve an equal or better performance in regard to reducing the environmental impact linked to nitrogen excretion. In particular, from 50 kg live weight (LW) to slaughter (about 170 kg LW), we compared three theses: (1) (C) traditional diet based on soy and maize; (2) (T1) iso-protein diet protein, pea-based; and (3) (T2) low-crude-protein diet, cereal-based. The results demonstrate that it is possible to obtain the same productive performance and quality characteristics of the meat while significantly (p < 0.01) reducing the nitrogen excretion by almost 30%.

Italian pigs for slaughter weigh between 150 and 170 kg, and their breeding is strictly regulated by the Protected Designation of Origin. Intensive production raises environmental concerns, in particular, nitrogen (N) emissions. To address these issues, low-crude-protein diet strategies have been proposed. However, few experiments have tested the effects of very low crude protein levels on performance and nitrogen efficiency, above all, in heavy pigs. The aim of our study was to explore new feeding solutions, compared to traditional ones, in accordance with PDO regulations, from 50 kg live weight to slaughtering: (1) traditional diet based on soy and maize; (2) iso-protein diet protein that is pea-based; and (3) low-crude-protein (−24.5% vs. C and T1 diets) diet that is cereal-based. Our results show that the use of different protein sources and the very low crude protein levels did not influence the technical efficiency and quality parameters; instead, a highly significant difference (p < 0.01) was recorded in the nitrogen efficiency of the cereal-based diet both in terms of nitrogen excretion and efficiency, achieving −28% and +21%, respectively. These results open up very interesting scenarios regarding the future feeding of heavy pigs and the cropping systems on which this is based.