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An increase in energy content of the diet results usually in improved feed efficiency and increased backfat (BF) depth and intramuscular fat (IMF) content of pork meat. Pigs for the industry of dry cured products are usually slaughtered at heavier weights (120 kg approximately), however, this increase in bodyweight (BW) reduces feed efficiency and increases the incidence of boar taint in meat. The hypothesis that an increase in energy content of diets with similar AA to NE ratio could result in an increase in energy intake and on the amount of fat deposited in the carcasses, and that such an effect could be more noticeable in IMC than in boars, with gilts showing intermediate results. The aim of this work was to study the effect of NE content of the diet on growth performance and carcass and meat quality traits of gilts, boars and IMC pigs slaughtered at 120 kg BW. In this study were utilized a total of 540 crossbred pigs with an initial body weight of 28.5 kg. The feeding program consisted of five periods in which pigs had free access to diets based on barley and soybean meal in mash form The dietary treatments used to investigate the effects of the net energy (NE) content were: 2.29, 2.33, 2.37, 2.41 and 2.45 Mcal NE/kg of the diet, but the Lys:NE ratio was maintained constant (4.15, 3.67, 3.14, 2.93 and 2.62, respectively). Individual BW and feed consumption per pen were recorded at 72, 90, 126, 143, 168 and 188 days of age (0, 18, 54, 71, 96 and 116 days of experiment).
An increase in dietary NE increased NE intake and decreased feed conversion ratio linearly. The IMC pigs showed greater feed intake and average daily gain than gilts and boars. Backfat depth increased and chilled and trimmed ham yield decreased, as the dietary NE increased. Backfat depth was greater for gilts and IMC than for boars. Also, gilts had greater carcass (P<0.001) and loin yields than boars and IMC. Diets with the greater NE content were more appropriate for the production of heavy pigs.
Cámara, L., Berrocoso, J.D., Sánchez, J.L., López-Bote, C.J. and Mateos, G.G. 2014. Influence of net energy content of the diets on productive performance and carcass merit of gilts, boars and immunocastrated males slaughtered at 120 kg BW. Meat Science 98; 773–780. http://dx.doi.org/10.1016/j.meatsci.2014.07.025