Two 4-wk trials (preliminary study) and three 5-wk trials (major study) were conducted to determine the effects of adding Yucca schidigera extract or anhydrous calcium chloride to nursery diets on the growth performance of nursery pigs and aerial ammonia concentration. The pigs were weaned between 13 and 15 d of age and had an initial BW of 3 to 6 kg. In each trial, pigs were allotted to three identical pig nursery rooms that were environmentally regulated. There were three diets (one diet per room): 1) control, containing 23% CP; 2) control plus 125 ppm of Yucca schidigera extract; and 3) control plus 1.95% anhydrous calcium chloride. Growth performance was recorded weekly. Aerial ammonia concentration was measured daily using aspiration detector tubes and during the last week of each trial using diffusion tubes. Manure samples were collected twice a week during the experimental period to determine ammonia and N concentrations and pH. Plasma urea concentration was determined in blood samples collected from the pigs at the end of each trial. Data were analyzed using split-plot and Latin square designs for the preliminary and major studies, respectively. Feed intake was similar among pigs fed all three diets. There were no differences in ADG and ADG/ADFI (G/F) between pigs fed the control diet and pigs fed the yucca extract diet (P > or = 0.41). In all trials, pigs fed the calcium chloride diet had lower ADG and G/F than pigs fed the other two diets (P < 0.05). In the preliminary study, aerial ammonia tended to be greater in the rooms in which pigs were fed the control diet than in the rooms with pigs fed the yucca extract diet (P = 0.08) and the calcium chloride diet (P = 0.11). In the major study, aerial ammonia increased weekly (diet x week; P < 0.001) in all rooms. In the 4th wk, ammonia concentrations were greater (P < 0.001) in the rooms in which pigs were fed the control diet than in the rooms in which the other two diets were fed. Dietary treatment had no effect on plasma urea concentration (P > or = 0.10), manure ammonia and N concentrations (P > or = 0.50), and manure pH (P > or = 0.78). Although aerial ammonia concentrations were relatively low, the addition of Yucca schidigera extract or calcium chloride to the diet of nursery pigs reduced ammonia concentrations in the nursery rooms.

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An experiment with 2 trials (28 d/trial) was conducted to determine body composition, tissue deposition, and utilization of Lys for protein deposition (PD) of barrows and gilts fed -Lys·HCl (CLys) or protein-bound Lys in soybean meal (SBM). Thirty-two growing pigs (16 barrows and 16 gilts; average initial BW of 18.6 kg) were used in each of 2 trials. Four pigs (2 barrows and 2 gilts) were euthanized at the start of each trial to determine initial body composition. The remaining pigs were euthanized at the end of the trials to determine empty-body composition and deposition rates of water, protein, fat, ash, and AA. Pigs were randomly allotted to 1 of 7 dietary treatments. There were 2 replications per treatment in each trial for a total of 4 replications. Dietary treatments consisted of a corn-SBM basal diet (0.48% Lys) and diets containing 0.56%, 0.65%, and 0.74% standardized ileal digestible (SID) Lys that were achieved by adding Lys to the basal diet from either SBM or CLys. Pigs fed the CLys-supplemented diets at 0.65% SID Lys had more ( < 0.05) body water (663 vs. 624 g/kg) and less ( < 0.01) body protein (153 vs. 160 g/kg) than pigs fed the SBM-supplemented diets. Body fat content decreased ( < 0.01) as the dietary Lys increased similarly for pigs fed Lys from SBM and pigs fed CLys. Gilts had greater ( = 0.05) body Lys content in body protein than barrows (7.68 vs. 7.52 g/100 g). Empty-body ash contents were not different between pigs fed CLys or SBM-supplemented diets. Water deposition and PD increased linearly ( < 0.01) with dietary Lys and were least ( < 0.01) in pigs fed the basal diet but were similar when comparing pigs fed CLys and SBM-supplemented diets at the same dietary Lys concentration. Lysine deposition showed a linear increase ( < 0.01) with dietary Lys but was not different between pigs fed the 2 Lys sources at the same concentration. Barrows and gilts did not differ in tissue deposition rates. Overall, empty-body contents and deposition rates of essential and nonessential AA were not different between pigs fed CLys and pigs fed SBM-bound Lys. The amount of SID Lys required for PD ranged between 0.09 and 0.13 g/g for both sources of Lys. The Lys deposition:SID Lys intake ratio was greater ( < 0.01) in gilts than barrows (0.62 vs. 0.56). Body composition, tissue deposition, and utilization of Lys for PD and Lys deposition were not different in pigs fed diets supplemented with -Lys·HCl with respect to protein-bound Lys in SBM.

An experiment consisting of two 4-wk trials was conducted to determine Lys use for growth and carcass traits in barrows and gilts fed individually or in groups. One hundred twelve growing pigs (56 barrows and 56 gilts; average initial BW of 18.6 kg) were used in each trial. Pigs were fed individually or in groups of 3. There were 28 pigs individually penned, and 84 pigs in 28 pens (3 pigs/pen). There were 2 replications per treatment in each trial for a total of 4 replications. Dietary treatments consisted of a corn-soybean meal (SBM) basal diet (0.48% Lys) and diets containing 0.56%, 0.65%, and 0.74% standardized ileal digestible (SID) Lys that were achieved by adding Lys to the basal diet from either SBM or crystalline source as L-Lys HCL (CLys). At the end of each trial, all pigs were scanned using real-time ultrasound to determine 10th-rib back fat depth and LM area, and fat-free lean gain (FFLG) was calculated. Blood samples were taken from all pigs weekly to determine plasma urea N (PUN). Pigs fed CLys and Lys from SBM were not different in final BW, ADG, ADFI, or G:F. The ADG and G:F increased linearly (P < 0.01) as dietary Lys concentration increased. The SID Lys intake increased linearly (P < 0.01) as dietary Lys concentration increased and was not different when comparing pigs fed diets with CLys or SBM. The amount of SID Lys required per unit of growth or BW gain increased linearly (about 13 to 15.50 g/kg) in pigs fed either CLys or SBM Lys. Pigs fed individually had a greater (P < 0.05) ADG (0.59 vs. 0.57 kg) and ADFI (1.36 vs. 1.29 kg) than pigs fed in groups. The SID Lys intake was greater (P < 0.05) in pigs fed individually in comparison with pigs fed in a group (8.51 vs. 8.06 g/d). Fat-free lean gain and LM area increased (P < 0.01) as dietary Lys concentration increased regardless of Lys source. Pigs fed CLys diets had a greater (P < 0.05) LM area than pigs fed SBM at 0.74% SID Lys. Gilts had a greater (P < 0.01) LM area (14.28 vs. 13.58 cm(2)) and FFLG (264 vs. 245 g/d) than barrows. Pigs fed individually with CLys had less (P < 0.01) PUN than pigs fed Lys from SBM. Barrows fed individually had less (sex × feeding method, P < 0.01) PUN than gilts (26.75 vs. 29.32 g/100 mL). The results indicate that Lys from SBM-bound and CLys source were utilized similarly for growth and carcass traits regardless of sex or feeding method.

Para determinar la digestibilidad total aparente de la materia seca (DMS), energía (EDA), y nitrógeno (DAN) de una mezcla de sorgo (MSO) con un complejo enzimático (CE) en dietas para cerdos en crecimiento, se realizó un experimento en dos periodos de ocho días cada uno. Se utilizaron 24 cerdos (35 kg de peso vivo) distribuidos en un diseño de bloques al azar (periodo como bloque) con cuatro dietas y seis cerdos por dieta en un arreglo factorial de tratamientos 2 × 2. Los factores fueron dos ingredientes (MSO y maíz) con o sin CE resultando en las siguientes dietas: basal con maíz (DBM); DBM con la adición del CE (DBM+CE); dieta a base MSO (DMSO) y DMSO+CE. Los cerdos fueron alojados individualmente en jaulas metabólicas para la recolección total de heces. Los datos fueron analizados mediante el programa estadístico PROC MIXED de SAS, aplicando pruebas de ANAVAR, utilizando el procedimiento GLM-Tukey. No se encontró efecto del CE sobre las variables evaluadas. La EDA varió significativamente (P = 0,003) entre los dos ingredientes con valores de 3641,49 ± 42,95 kcal/kg MS y 3540,61 ± 55,82 kcal/kg MS para DBM y DMSO, respectivamente. La DAN fue mayor (P = 0,002) en la DBM (81,75±1,55 %) con respecto a la DMSO (77,06 ± 3,44%). Se concluye que la adición del CE no afectó la DMS, DAN y EDA de la mezcla de granos de sorgo evaluada en dietas para cerdos en crecimiento.