Dietary Protein Reduction in Lean Pigs From Pietrain Paternal Line Under Commercial Setting: An Interplay Between Nitrogen Efficiency and Meat Attributes.

A trial was conducted to research the impact of reducing dietary crude protein (CP) levels from 14.8% to 12.6% in the finishing diet (90-120 kg of body weight) of lean pigs, with an essential AA supply (8.8 g Lys, 2.1 g Met, 6.7 g Thr, 5.5 g Ile, and 6.7 g Val, per kilogram of feed) in intact males and females under commercial setting. The productive performances and nitrogen (N) balance, blood markers related to protein metabolism, apparent digestibility of nutrients, carcass, and meat quality were evaluated. This dietary CP restriction did not impair the growth performances, decreased the N excretion, and did not affect the apparent digestibility of most nutrients, except phosphorus digestibility, which was reduced in the low-CP diet. The responses to this dietary CP restriction were independent of sex, except the serum urea concentration and total proteins, which were only steadily reduced in intact males fed the low-CP diet. The low-CP diet reduced the nutritional pork quality by increasing the moisture content, although the technological characteristics of meat were not affected. Further studies are required to improve the sex-tailored feeding strategies for high-conformed lean pigs in an environmentally friendly context.