Metabolizable energy levels in diets with high lysine for growing and finishing pigs

Abstract

The objective of this experiment was to evaluate the effects of metabolizable energy (ME) levels in diets with high digestible lysine concentration on performance, carcass traits, and meat quality of barrows from 95 to 158 days of age. Eighty commercial hybrid barrows (50 ± 1.82 kg) selected for lean meat deposition, were assigned to four dietary treatments (3,150, 3,235, 3,320, and 3,400 kcal EM kg-1) in a randomized design with 10 replicate pens per treatment and two pigs per pen. From 95 to 116 days of age, we observed no effects of ME on final body weight (FBW), average daily gain (ADG), metabolizable energy intake (MEI), and feed conversion (F: G). Average daily feed intake (ADFI) decreased linearly with increasing ME levels (? = 5.79961 - 0.00096790X - r2 = 0.89). From 95 to 137 days of age, no effects of ME were observed on final body weight (FBW), average daily gain (ADG), metabolizable energy intake (MEI), and feed conversion (F: G). Average daily feed intake (ADFI) decreased linearly with increasing ME (?= 6.1176 - 0.001X - r2= 0.97). From 95 to 158 days, of age no effects of ME were observed on FBW and ADG. Dietary ME influenced the ADFI and F: G, which decreased linearly with increasing ME concentrations (?= 8.12951 - 0.00149X - r2= 0.99; ?= 6.0914 - 0.001X - r² = 0.75, respectively). There was a linear increase in loin eye area (LEA) with increasing ME (? = - 29.851 + 0.0207 X - r² = 0.87). Backfat thickness, pH, and temperature, measured at different times after slaughter (0 min, 45 min, 3 h, and 24 h), were not affected by dietary ME. The level of ME also did not affect the meat quality parameters Color L*, Color a*, Color b*, Warner-Bratzler shear force, thaw water losses, cooking water losses, sum of water losses, intramuscular fat content, and TBARS. Diets with 3,400 kcal kg-1 ME, corresponding to 2.75, 2.57, and 2.31 g digestible lysine/Mcal of ME for pigs from 95 to 116, 116 to 137, and 95 to 158 days of age, respectively, resulted in best performance and carcass traits, without negative effects on meat quality.