The effect of protein restriction during the growing period on carcass, meat and fat quality of heavy barrows and gilts

• Certain levels of backfat depth and intramuscular fat guarantee the correct processing and high quality of pork products.
• The protein restriction during the growing period might carry out an increase of fatness.
• To check it, carcass and meat variables were evaluated in heavy pigs.
• The dietary protein restriction promoted positive effects in barrows and gilts.

Nutritional strategies are being researched in pigs to increase fatness and then to improve quality of dry-cured products. A total of 160 Duroc × (Landrace × Large White) pigs, 50% barrows and 50% gilts, were used in a trial. During the growing period (73–118 d of age), four feeds were formulated with decreasing levels of crude protein (CP; 21.6, 17.7, 14.7 and 13.5%) to achieve 1.10, 0.91, 0.78 and 0.52% of total Lysine, respectively. From 118 d until slaughter, at 123 kg (183, 181, 178 or 192 d of age, respectively), a common diet was provided (17.7% CP and 0.91% Lysine). Barrows had fatter carcasses than gilts but intramuscular fat (IMF) proportion was similar for both. Dietary CP restriction promoted wider backfat depth and pork with higher IMF percentage which was more monounsaturated and less polyunsaturated. We conclude that CP restriction during the grower period improves desirable carcass and meat traits in barrows and gilts intended for dry-cured products.