Effects of dietary vitamin E concentration and source on sow, milk, and pig concentrations of α-tocopherol.

A total of 126 gilts and sows (PIC 1050) and their litters were used to determine the effects of dietary vitamin E concentration and source on sow plasma, milk, and pig concentrations of α-tocopherol. Additionally, we estimated the bioavailability of D-α-tocopheryl acetate (D-α-TAc) relative to DL-α-tocopheryl acetate (DL-α-TAc) when fed in diets containing dried distillers grains with solubles (DDGS). The 6 dietary treatments included DL-α-TAc at 44 and 66 mg/kg and D-α-TAc at 11, 22, 33, and 44 mg/kg. From breeding to d 69 of gestation, sows were fed 2.0 kg/d of a diet containing 40% DDGS, 0.30 mg/kg added Se, and no added vitamin E. Vitamin E treatments were fed from d 70 of gestation through weaning. Plasma was collected from sows on d 69 and 100 of gestation, at farrowing, and at weaning. Colostrum and milk samples were also collected. Plasma from 3 pigs per litter and heart and liver samples from 1 pig per litter were collected at weaning. Plasma, milk, and tissues from 6 litters per treatment were analyzed for α-tocopherol. Although tissue, plasma, and milk concentrations of α-tocopherol were the primary response criteria of interest, sow and litter performance were measured. As expected, treatment effects were not observed for lactation feed intake, sow BW, or backfat measurements. A trend (P = 0.085) for a treatment effect on average pig BW at weaning was detected, with pigs nursing sows fed 44 mg/kg DL-α-TAc weighing less because of a younger weaning age. No other differences in litter performance were observed. As D-α-TAc increased in the diet, sow plasma, colostrum, and milk, pig plasma, and pig heart concentrations of α-tocopherol increased (linear, P < 0.03). Sows fed diets with 44 mg/kg D-α-TAc had increased (P < 0.03) plasma and colostrum and pig plasma concentrations of α-tocopherol compared with sows fed 44 mg/kg of DL-α-TAc. Sows fed 66 mg/kg DL-α-TAc also had greater (P = 0.022) plasma α-tocopherol at weaning than sows fed 44 mg/kg DL-α-TAc. Bioavailability coefficients for D-α-TAc relative to DL-α-TAc ranged from 1.9 to 4.2 for sow and pig plasma α-tocopherol, 2.9 to 3.6 for colostrum α-tocopherol, 1.6 for milk α-tocopherol, and 1.7 to 2.0 for pig heart and liver α-tocopherol. Overall, this study indicates the bioavailability for D-α-TAc relative to DL-α-TAc varies depending on the response criteria but is greater than the standard potency value of 1.36.

Effects of porcine circovirus type 2 vaccine and increasing standardized ileal digestible lysine:metabolizable energy ratio on growth performance and carcass composition of growing and finishing pigs.

Four experiments were conducted to examine the effect of porcine circovirus type 2 (PCV2) vaccination on the response of growing and finishing pigs (PIC 337 × 1050) to increasing dietary Lys. Experiments 1 and 2 evaluated 38- to 65-kg gilts and barrows, respectively, and Exp. 3 and 4 evaluated 100- to 120-kg gilts and barrows, respectively. Gilts and barrows were housed separately in different barns. Treatments were allotted in a completely randomized design into 2 × 4 factorials with 2 PCV2 treatments (PCV2-vaccinated and nonvaccinated) and 4 standardized ileal digestible (SID) Lys:ME ratios (2.24, 2.61, 2.99, and 3.36 g/Mcal in Exp. 1 and 2 and 1.49, 1.86, 2.23, and 2.61 g/Mcal in Exp. 3 and 4) within each experiment. There were 5 pens per treatment. At the start of Exp. 1 and 2, there were more pigs per pen (P < 0.001) in vaccinated pens because vaccinated pigs had a greater survival rate than nonvaccinated pigs, and this increase was maintained throughout the experiments. Removal rate approached 30% in nonvaccinated barrows and more than 20% in nonvaccinated gilts. Observation suggested that the removals were largely due to PCV2-associated disease. No PCV2 vaccination × SID Lys:ME ratio interactions (P > 0.10) were observed in any of the 4 studies. In Exp. 1 and 2, PCV2-vaccinated pigs had increased (P < 0.001) ADG compared with nonvaccinated pigs. The growth response was primarily due to increases in ADFI, which suggests that vaccinated pigs have a greater Lys requirement (g/d) than nonvaccinated pigs. In Exp. 1, increasing the SID Lys:ME ratio increased (quadratic; P < 0.04) ADG and G:F, with pigs fed the 2.99 g/Mcal ratio having the greatest ADG and G:F. In Exp. 2, increasing the SID Lys:ME ratio improved (linear; P < 0.001) G:F. In Exp. 3, ADG and G:F increased (P < 0.05) in a quadratic manner as the SID Lys:ME ratio fed increased. In Exp. 4, increasing the SID Lys:ME ratio increased ADG (linear; P < 0.001) and G:F (quadratic; P = 0.03). Although PCV2 vaccination improved growth, the corresponding increase in ADFI did not increase the optimal SID Lys:ME ratio for growing and finishing barrows and gilts.

Effects of increasing dietary standardized ileal digestible lysine for gilts grown in a commercial finishing environment.

Three experiments were conducted to determine the effects of increasing dietary standardized ileal digestible (SID) Lys on growing and finishing gilts. Diets in all 3 experiments were corn-soybean meal-based and contained 0.15% l-Lys•HCl and 3% added fat from choice white grease. Desired SID Lys concentrations were achieved by altering levels of corn and soybean meal in the diet. Each experiment consisted of 6 treatments with 7 pens per treatment and approximately 27 gilts (PIC 337 × 1050) per pen. In Exp. 1, 1,085 gilts (initially 38.2 kg) were fed diets formulated to contain SID Lys concentrations of 0.7, 0.8, 0.9, 1.0, 1.1, or 1.2% for 28 d, which were analyzed to be total Lys concentrations of 0.78, 0.86, 0.99, 1.06, 1.14, and 1.24%, respectively. As SID Lys increased, ADG and G:F improved (quadratic, P < 0.003) with optimal performance reached at the SID Lys level of 1.1% or SID Lys:ME ratio of 3.16 g/Mcal. Broken-line analysis indicated breakpoints of 1.03 and 1.05% SID Lys for ADG and G:F, respectively. Gilts in this trial required approximately 21.8 g of SID Lys intake per kilogram of BW gain from 38 to 65 kg. In Exp. 2, 1,092 (initially 55.2 kg) gilts were fed diets formulated to contain SID Lys concentrations of 0.66, 0.74, 0.82, 0.90, 0.98, or 1.06% for 28 d, which were analyzed to be total Lys concentrations of 0.75, 0.73, 0.84, 0.90, 0.95, and 0.97%, respectively. Both ADG (quadratic, P = 0.12) and G:F improved (linear, P < 0.001) as SID Lys increased, with broken-line analysis of ADG indicating a requirement estimate of 0.90%, which corresponds to a SID Lys:ME ratio of 2.58 g/Mcal. Gilts in this trial required approximately 19.6 g of SID Lys per kilogram of BW gain from 55 to 80 kg. In Exp. 3, 1,080 gilts (initially 84.1 kg) were fed diets formulated to contain SID Lys concentrations of 0.54, 0.61, 0.68, 0.75, 0.82, or 0.89% for 29 d, which were analyzed to be total Lys concentrations of 0.62, 0.92, 0.79, 0.99, 0.93, and 1.07%, respectively. As the SID Lys concentration increased, ADG and G:F improved (linear, P < 0.001), and performance responses were maximized at the greatest SID Lys level of 0.89% or SID Lys:ME ratio of 2.55 g/Mcal of ME. Gilts in this trial required 23.0 g of SID Lys per kg of BW gain from 85 to 110 kg. The ideal SID Lys:ME ratio was based on the requirement determined by broken-line analysis in Exp. 1, 2, and 3, with the greatest level being tested in Exp. 3. This equation, SID Lys:ME ratio = -0.011 × BW, kg + 3.617, estimates the optimal SID Lys:ME ratios for growth of gilts (PIC 337 × 1050) in this commercial finishing environment. These studies showed growth performance advantages to increasing SID Lys for growing and finishing gilts over previously reported optimal levels, particularly in the later finishing stages.

Selection of fecal enterococci exhibiting tcrB-mediated copper resistance in pigs fed diets supplemented with copper.

Copper, as copper sulfate, is increasingly used as an alternative to in-feed antibiotics for growth promotion in weaned piglets. Acquired copper resistance, conferred by a plasmid-borne, transferable copper resistance (tcrB) gene, has been reported in Enterococcus faecium and E. faecalis. A longitudinal field study was undertaken to determine the relationship between copper supplementation and the prevalence of tcrB-positive enterococci in piglets. The study was done with weaned piglets, housed in 10 pens with 6 piglets per pen, fed diets supplemented with a normal (16.5 ppm; control) or an elevated (125 ppm) level of copper. Fecal samples were randomly collected from three piglets per pen on days 0, 14, 28, and 42 and plated on M-Enterococcus agar, and three enterococcal isolates were obtained from each sample. The overall prevalence of tcrB-positive enterococci was 21.1% (38/180) in piglets fed elevated copper and 2.8% (5/180) in the control. Among the 43 tcrB-positive isolates, 35 were E. faecium and 8 were E. faecalis. The mean MICs of copper for tcrB-negative and tcrB-positive enterococci were 6.2 and 22.2 mM, respectively. The restriction digestion of the genomic DNA of E. faecium or E. faecalis with S1 nuclease yielded a band of ∼194-kbp size to which both tcrB and the erm(B) gene probes hybridized. A conjugation assay demonstrated cotransfer of tcrB and erm(B) genes between E. faecium and E. faecalis strains. The higher prevalence of tcrB-positive enterococci in piglets fed elevated copper compared to that in piglets fed normal copper suggests that supplementation of copper in swine diets selected for resistance.

Effects of copper sulfate, tri-basic copper chloride, and zinc oxide on weanling pig performance.

Three experiments were conducted to evaluate the effects of increasing dietary Cu and Zn on weanling pig performance. Diets were fed in 2 phases: phase 1 from d 0 to 14 postweaning and phase 2 from d 14 to 28 in Exp. 1 and 2 and d 14 to 42 in Exp. 3. The trace mineral premix, included in all diets, provided 165 mg/kg of Zn from ZnSO(4) and 16.5 mg/kg of Cu from CuSO(4). In Exp. 1, treatments were arranged in a 2 × 3 factorial with main effects of added Cu from tri-basic copper chloride (TBCC; 0 or 150 mg/kg) and added Zn from ZnO (0, 1,500, or 3,000 mg/kg from d 0 to 14 and 0, 1,000, or 2,000 mg/kg from d 14 to 28). No Cu × Zn interactions were observed (P > 0.10). Adding TBCC or Zn increased (P < 0.05) ADG and ADFI during each phase. In Exp. 2, treatments were arranged in a 2 × 3 factorial with main effects of added Zn from ZnO (0 or 3,000 mg/kg from d 0 to 14 and 0 or 2,000 mg/kg from d 14 to 28) and Cu (control, 125 mg/kg of Cu from TBCC, or 125 mg/kg of Cu from CuSO(4)). No Cu × Zn interactions (P > 0.10) were observed for any performance data. Adding ZnO improved (P < 0.02) ADG and ADFI from d 0 to 14 and overall. From d 0 to 28, supplementing CuSO(4) increased (P < 0.02) ADG, ADFI, and G:F, and TBCC improved (P = 0.006) ADG. In Exp. 3, the 6 dietary treatments were arranged in a 2 × 2 factorial with main effects of added Cu from CuSO(4) (0 or 125 mg/kg) and added Zn from ZnO (0 or 3,000 mg/kg from d 0 to 14 and 0 or 2,000 mg/kg from d 14 to 42). The final 2 treatments were feeding added ZnO alone or in combination with CuSO(4) from d 0 to 14 and adding CuSO(4) from d 14 to 42. Adding ZnO increased (P < 0.04) ADG, ADFI, and G:F from d 0 to 14 and ADG from d 0 to 42. Dietary CuSO(4) increased (P < 0.004) ADG and ADFI from d 14 to 42 and d 0 to 42. From d 28 to 42, a trend for a Cu × Zn interaction was observed (P = 0.06) for ADG. This interaction was reflective of the numeric decrease in ADG for pigs when Cu and Zn were used in combination compared with each used alone. Also, numerical advantages were observed when supplementing Zn from d 0 to 14 and Cu from d 14 to 42 compared with all other Cu and Zn regimens. These 3 experiments show the advantages of including both Cu and Zn in the diet for 28 d postweaning; however, as evident in Exp. 3, when 3,000 mg/kg of Zn was added early and 125 mg/kg of Cu was added late, performance was similar or numerically greater than when both were used for 42 d.