A total of 1,040 growing pigs (initially, 22.9 ± 4.3 kg) were used in a 115-d study to evaluate the effects of 2 mycotoxin mitigation strategies, a preservative blend (PB) and a yeast product (YP), on the growth performance of swine fed diets containing corn dried distillers grains with solubles naturally contaminated with deoxynivalenol (DON). The PB consists of preservatives, antioxidants, AA, and direct-fed microbials and is included in diets to help pigs cope with the toxic effects of ingested mycotoxins. The YP works as an adsorbent to bind and prevent the absorption of mycotoxins in the gastrointestinal tract. Pigs were allotted to pens by initial BW and sex; pens were then assigned to treatments in a randomized block design with initial BW and sex serving as the blocking factors. Pens were randomly allotted to 1 of 4 dietary treatments consisting of a positive control (PC) containing <1 mg kg(-1) DON, a negative control (NC) formulated to contain 4 mg kg(-1) DON, NC with PB, and NC with YP. From d 0 to 42 and 42 to 84, no effect of diets containing PB or YP were observed for any of the growth criteria evaluated. From d 84 to 115, pigs fed PC or diets containing PB had improved (P < 0.05) ADG compared to pigs fed NC or diets containing YP, whereas pigs fed YP had improved (P < 0.05) ADG compared to those fed NC. Pigs fed diets containing PB or YP had improved (P < 0.05) ADFI and G:F compared to pigs fed NC. Overall (d 0 to 115), pigs fed diets containing PB had improved (P < 0.05) ADG, ADFI, and G:F compared to pigs fed NC. These results indicate that PB may be a suitable mycotoxin mitigation strategy in growing swine fed diets naturally contaminated with DON.

Covariance analysis limits error, the degree of nuisance variation, and overparameterizing factors to accurately measure treatment effects. Data dealing with growth, carcass composition, and genetics often use covariates in data analysis. In contrast, nutritional studies typically do not. The objectives of this study were to 1) determine the effect of feeding diets containing dehulled, degermed corn, corn-soybean meal, or distillers dried grains with solubles on nutrient digestibility coefficients, 2) evaluate potential interactive effects between initial and final treatment diets on the final treatment diet effects, and 3) determine if initial criterion (digestibility or physiological values) would effectively correct for variation among pigs that could thereby affect final treatment diet digestibility coefficients. Seventy-two crossbred barrows [(Yorkshire × Landrace × Duroc) × Chester White] were randomly assigned to 1 of the 3 diets within initial dietary treatment for Phase-2 (P2; 14 d). Fecal and blood samples were collected after feeding the Phase-1 (P1) diets for 14 d (trial d-14) and on d 28 after feeding the P2 diets for 14 d. Fecal samples were dried and analyzed for C, ether extract, GE, N, NDF, P, and S. Plasma samples were analyzed for plasma urea N and triacylglycerides. Pigs were fed diets that differed widely in CP, NDF, and P, resulting in an overall decrease in C, GE, NDF, N, P, and S digestibility and plasma urea N and triacylglycerides as dietary fiber increased in P1 and P2 (P < 0.10). There were no differences in P2 criteria due to blocking for the P1 diet. There tended (P = 0.10 to 0.20) to be P1 × P2 interactions for NDF and S, indicating that the response of pigs to the P2 diet may depend on the P1 diet. In contrast, when the P1 variable was used as a covariate for P2 data, it was statistically significant for GE, NDF, N, S, and plasma urea N (P < 0.10) whereas C and ether extract showed tendencies but not for P digestibility or plasma triacylglycerides. In conclusion, if initial diets are known, subsequent treatments should be balanced for the initial diet because of potential of initial diet × final diet interactions. If the initial diets are not known, then the initial digestibility coefficient would be effective in reducing the variation associated with subsequently obtained data and should be considered as a covariate in future grower-finisher swine digestibility research.

Accurate estimations of nutrient digestion and retention are critical in nutrient balance and feed evaluation studies because errors that occur are often additive. However, there is no standard universal method for drying feces, urine, or excreta before laboratory analysis. The objective of this study was to evaluate the impact of 4 different drying methods on nutrient concentrations in feces, urine, and excreta. Twelve individually penned growing pigs were fed 1 of 3 diets and 16 pens of 10 growing broilers were fed 1 of 4 diets that differed in NDF and CP. Feces, urine, and excreta that varied in nutrient composition were collected after 7 d of diet adaptation. Samples were dried using 1 of 4 methods: undried (UD), freeze-dried (FD), oven-dried at 55 °C for 48 h (OD55), or oven-dried at 100 °C for 48 h (OD100), after which DM, GE, N, C, and S were determined. In swine feces, drying resulted in a loss of GE (P < 0.10) and S (P < 0.01) by 5 and 58%, respectively, compared with UD feces. There was no difference (P ≥ 0.36) among drying method on DM, GE, N, C, or S concentrations. There were no differences (P ≥ 0.12) in urinary GE due to drying or between drying methods; however, urinary DM was greatest by FD compared with OD (P < 0.05) and greater for OD55 compared with OD100 (P < 0.01). In poultry excreta, GE (P < 0.05), N (P < 0.10), and S (P < 0.01) were reduced by drying by an average of 6, 10, and 66%, respectively. There were no differences (P ≥ 0.50) among drying methods except FD excreta had a greater S concentration than OD (P < 0.10). Regardless of drying method, some GE and N loss appears to be inevitable, but there is no apparent advantage between FD and OD. The apparent greater S losses warrant further investigation.

and ImplicationsDrying method was evaluated based on the impact it had on gross energy and nitrogen concentration of swine feces and urine, and nitrogen in poultry excreta, Twelve individually penned growing pigs were fed one of three diets and 16 pens of 10 growing broilers were fed one of four diets that differed in NDF and CP. Feces, urine, and excreta were collected after diet adaptation and were assumed to vary widely in nutrient composition. Following collection, samples were dried using one of four methods: UD-undried, FD-freeze dried, OD55-oven dried at 55°C for 48 h, or OD100-oven dried at 100°C for 48 h, after which dry matter gross energy, nitrogen, carbon, and sulfur were determined. In swine feces, drying resulted in a loss of GE and S, but among the various drying methods, there was no difference for dry matter, gross energy, nitrogen, carbon and sulfur concentrations. There were no differences in urinary gross energy due to drying or among drying methods; however urinary dry matter was highest for FD compared to OD and higher for OD55 compared to OD100. In poultry excreta, gross energy, nitrogen, and S were reduced by drying, but there were no differences among the drying methods. Regardless of drying method, some loss of gross energy and nitrogen appears to be inevitable, but there is no apparent advantage between freeze drying and oven drying.

BackgroundIndigestible markers are commonly utilized in digestion studies, but the complete disappearance or maximum appearance of a marker in feces can be affected by diet composition, feed intake, or an animal’s BW. The objectives of this study were to determine the impact of previous (Phase 1, P1) and current- (Phase 2, P2) diet composition on marker disappearance (Cr) and appearance (Ti) in pigs fed 3 diets differing in NDF content.ResultsWhen pigs were maintained on the 25.1, 72.5, and 125.0 g/kg NDF diets, it took 5.1, 4.1, and 2.5 d, respectively, for Cr levels to decrease below the limit of quantitation; or 4.6, 3.7, or 2.8 d, respectively, for Ti to be maximized. These effects were not, however, independent of the previous diet as indicated by the interaction between P1 and P2 diets on fecal marker concentrations (P < 0.01). When dietary NDF increased from P1 to P2, it took less time for fecal Cr to decrease or fecal Ti to be maximized (an average of 2.5 d), than if NDF decreased from P1 to P2 where it took longer for fecal Cr to decrease or fecal Ti to be maximized (an average of 3.4 d).ConclusionsBecause of the wide range in excretion times reported in the literature and improved laboratory methods for elemental detection, the data suggests that caution must be taken in considering dietary fiber concentrations of the past and currently fed diets so that no previous dietary marker addition remains in the digestive tract or feces such that a small amount of maker is present to confound subsequent experimental results, and that marker concentration have stabilized when these samples are collected.