Suchergebnisse

Two consecutive experiments were conducted using 480 pigs each with six replicate pens per treatment and 10 pigs per pen to evaluate the effect of standardized ileal digestible (SID) Lys (0.81, 0.91, 1.01, and 1.11%) in diets containing ractopamine (RAC; 10 or 20 mg kg-1) on growth and carcass traits of barrows in a commercial production system. There were no effects of either RAC levels or the interaction between RAC and SID Lys levels on any of the performance and carcass variables. No lack of fit was detected in the response surface analysis. From d 0 to 21, there was no effect of SID Lys levels on ADFI. However, as SID Lys increased, there was a linear increase in ADG and G:F. As SID Lys increased, the ADG, G:F, loin depth, and lean percentage improved linearly from d 0 to 28, with no effect on ADFI and backfat thickness. In conclusion, performance and carcass traits of pigs fed RAC (10 or 20 mg kg-1) in a commercial finishing facility are improved by up to 1.11% SID Lys supplementation. There is no additional benefit of feeding 20 mg kg-1 RAC in comparison with 10 mg kg-1 RAC.

Two experiments were conducted to determine the effects of dietary net energy content (NE) on performance and carcass traits of finishing barrows fed low crude protein (CP) diets. Pigs (60.0 ± 2.41 kg, Exp. 1; 90.0 ± 2.96 kg, Exp. 2) were allotted in randomized design to four dietary treatments. Exp. 1 had nine pens treatment-1 and Exp. 2 had eight pens treatment-1, with two pigs in all pens. The treatments were as follows: 179 g kg-1 CP and 2589 kcal NE kg-1, 134 g kg-1 CP and 2631 kcal NE kg-1, 134 g kg-1 CP and 2589 kcal NE kg-1, and 134 g kg-1 and 2589 kcal NE kg-1 (pair-feeding to 179 g kg-1 CP and 2589 kcal NE kg-1) in Exp. 1 and 166 g kg-1 and 2604 kcal NE kg-1, 123 g kg-1 CP and 2645 kcal NE kg-1, 123 g kg-1 CP and 2604 kcal NE kg-1, and 12.34% CP and 2604 kcal NE kg-1 (pair feeding to 166 g kg-1 CP and 2604 kcal NE kg-1) in Exp. 2. In Exp. 1, there was no effect of CP or NE on any performance and carcass traits evaluated. In Exp. 2, the greatest result of average daily gain was obtained with 123 g kg-1 CP and 2645 kcal NE kg-1. There was no effect of CP or NE on any other performance and carcass traits evaluated. For 60 to 90 kg barrows, reducing the CP of the diet from 179 g kg-1 to 134 g kg-1, adjusting or not adjusting the NE content of the diets with 134 g kg-1 CP does not compromise performance or carcass traits. For 90 to 110 kg barrows, reducing the CP of the diet from 16.62 to 123 g kg-1, while maintaining the same NE content (2604 kcal kg-1) of the diet with 166 g kg-1 CP does not compromise performance or carcass traits.

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.

The objective of the study was to evaluate the effects of glutamine and glutamate (Gln/Glu) on the growth performance and immune response of nursery pigs fed different digestible lysine content. Two hundred and sixteen piglets, weaned at 21 days old, were assigned to a randomized block design according to their initial body weight (BW), in a 2 × 2 factorial arrangement with two levels of lysine (control-lys and low-lys) and two levels of Gln/Glu (0 and 12 g kg-1), with nine replicates. At 26 d, piglets consuming the low-lys diet not supplemented with Gln/Glu presented a higher (P < 0.01) incidence of diarrhea than the other treatments. From 21 to 32 d of age, the piglets fed the control-lys diets performed better than those fed low-lys diets (P < 0.01). From 21 to 42 d of age, there was a correlation (P < 0.01) between lysine level and Gln/Glu supplementation for average daily feed intake (ADFI) and feed conversion (FC). Gln/Glu supplementation improved (P < 0.05) the ADFI of pigs fed the low-lys diets, resulting in a higher (P < 0.01) average daily weight gain (ADG) and BW; however, worse (P < 0.05) FC. Piglets consuming control-lys diets had higher (P < 0.05) serum urea nitrogen concentration (SUN) and IgG than low-lys piglets. In addition, Gln/Glu supplementation correlated with higher (P < 0.01) SUN. Dietary supplementation of glutamine and glutamate improved the growth performance of weaned piglets from 21 to 42 days of age, regardless of the diets' lysine levels. In addition, reducing lysine levels 10% below the requirement negatively affects the growth performance and the immune response of nursery piglets.