Further Investigation Evaluating the Effect of Dietary Chromium Further Investigation Evaluating the Effect of Dietary Chromium Propionate and Yucca schidigera Supplementation in Finishing Propionate and Yucca schidigera Supplementation in Finishing Pig Diets Pig Diets

Summary A total of 2,430 pigs (PIC 359 × 1050; initial BW = 64.6 lb) were used to evaluate the effects of dietary chromium propionate (Cr; KemTRACE Cr, Kemin Industries, Des Moines, IA) and a Yucca schidigera -based extract (Micro-Aid; DPI Global, Porterville, CA) on growth performance of finishing pigs housed in commercial conditions. Pigs were placed in balanced, mixed-gender pens (27 pigs per pen), blocked by average pen BW, and randomly assigned to treatment. Diets were corn-soybean meal-based and were formulated in 5 dietary phases to meet or exceed NRC 6 requirement estimates. Dietary treatments were fed for the full duration of the study and were arranged in a 2 × 3 factorial with 14 pens per treatment. Main effects included chromium (0 or 200 ppb added Cr), and Yucca schidigera extract (0, 62.5, or 125 ppm active ingredient). For the overall study, a marginally significant (linear; P ≤ 0.072) Cr × Yucca schidigera interaction was observed for ADG and ADFI. Pigs fed Yucca schidigera without added Cr had similar ADG and ADFI; however, pigs fed added Cr had increased ADG and ADFI as Yucca schidigera increased from 62.5 to 125 ppm. Added Cr had no effect on F/G ( P > 0.05). Increasing Yucca schidigera resulted in a marginally

Further Investigation Evaluating the Effect of Dietary Chromium Propionate and Yucca schidigera Supplementation in Finishing Pig Diets 1,2 J.T. Gebhardt, J.C. Woodworth, M.D. Tokach, J.M. DeRouchey, R.D. Goodband, J.A. Loughmiller, 3 A.L. de Souza, 3 M.J. Rincker, 4  and S.S. Dritz 5 Summary A total of 2,430 pigs (PIC 359 × 1050; initial BW = 64.6 lb) were used to evaluate the effects of dietary chromium propionate (Cr; KemTRACE Cr, Kemin Industries, Des Moines, IA) and a Yucca schidigera-based extract (Micro-Aid; DPI Global, Porterville, CA) on growth performance of finishing pigs housed in commercial conditions.Pigs were placed in balanced, mixed-gender pens (27 pigs per pen), blocked by average pen BW, and randomly assigned to treatment.Diets were corn-soybean meal-based and were formulated in 5 dietary phases to meet or exceed NRC 6 requirement estimates.Dietary treatments were fed for the full duration of the study and were arranged in a 2 × 3 factorial with 14 pens per treatment.Main effects included chromium (0 or 200 ppb added Cr), and Yucca schidigera extract (0, 62.5, or 125 ppm active ingredient).For the overall study, a marginally significant (linear; P ≤ 0.072) Cr × Yucca schidigera interaction was observed for ADG and ADFI.Pigs fed Yucca schidigera without added Cr had similar ADG and ADFI; however, pigs fed added Cr had increased ADG and ADFI as Yucca schidigera increased from 62.5 to 125 ppm.Added Cr had no effect on F/G (P > 0.05).Increasing Yucca schidigera resulted in a marginally significant poorer (quadratic; P = 0.057) F/G.The main effect of added Yucca schidigera on final BW (quadratic; P = 0.012) resulted in pens which were supplemented with 62.5 ppm having the lowest final BW.Carcass characteristics, including HCW, loin depth, backfat, percentage lean, and percentage yield, were not influenced by added Cr (P ≥ 0.278).Added Yucca schidigera did not influence loin depth, backfat, percentage lean, or percentage yield (P ≥ 0.152).In summary, adding Cr propionate along with Yucca schidigera led

Introduction
Addition of Cr in growing and finishing pig diets was recently summarized in a metaanalysis, and results indicated potential benefits of Cr supplementation including improved ADG, F/G, carcass percentage lean, and LM area along with a reduction in backfat thickness. 7However, a great deal of variation in responses among studies has been observed, thus further evaluation in a commercial setting is necessary.Previous research by our group in field-based research settings has shown mixed results; 8,9 reinforcing the lack of a clear response, especially in production settings.In addition, the NRC 6 does not provide an estimate for biological requirement in swine, indicating further evaluation is warranted.
Yucca schidigera-based extracts have been used to control nitrogenous gaseous emissions in a variety of livestock, including poultry, swine, beef, and dairy cattle, through its saponin characteristics. 10Research evaluating the effects of Yucca schidigera supplementation in poultry is more extensive than swine, and would suggest an improvement in F/G. 11Research related to the impact of Yucca schidigera on blood metabolites in swine is currently very limited, and there is little research evaluating potential interactions between Cr and Yucca schidigera-based feed additives.However, in one previous experiment, inclusion of supplemental Cr in addition to Yucca schidigera did not result in any synergistic effects, but Yucca schidigera supplementation resulted in a marginally significant increase in overall ADFI, while added Cr increased backfat depth and reduced percentage lean. 7Therefore, the objective of this experiment was to further determine the effects of Cr supplementation at increasing levels of a Yucca schidigera-based extract on growth performance and carcass composition of pigs housed in a commercial environment.
10 ft) was equipped with a 4-hole stainless steel feeder and cup waterer for ad libitum access to feed and water and allowed approximately 6.6 ft 2 /pig.Feed additions to each individual pen were made and recorded by a robotic feeding system (FeedPro; Feedlogic Corp., Wilmar, MN).
A total of 2,430 pigs (PIC 359 × 1050; initial BW = 64.6 lb) were used to evaluate the effects of dietary supplementation of chromium propionate (Cr; KemTRACE Cr, Kemin Industries, Des Moines, IA) and Yucca schidigera-based extract (Micro-Aid; DPI Global, Porterville, CA) on growth performance of finishing pigs housed in commercial conditions.Pigs were placed in balanced, mixed-gender pens (27 pigs per pen), blocked by average pen BW, and randomly assigned to treatment.Diets were cornsoybean meal-based and were formulated in 5 dietary phases to meet or exceed NRC 6 requirement estimates within phase.Dietary treatments were fed for the full duration of the study and were arranged in a 2 × 3 factorial.Main effects included added Cr (0 and 200 ppb added Cr from Cr propionate; KemTRACE Cr, Kemin Industries, Des Moines, IA), and Yucca schidigera extract (0, 62.5, and 125 ppm, Micro-Aid; DPI Global, Porterville, Ca).All diets were manufactured at a commercial feed mill (New Horizon Feeds, Pipestone, MN; Table 1) and were fed in meal form.
Samples of the complete feed were taken from feeders at the beginning and end of each phase.Subsamples of each diet were then submitted for proximate analysis (Ward Laboratories, Inc., Kearney, NE) and Cr analysis (University of Guelph Agriculture & Food Laboratory; Guelph, ON).Pens of pigs were weighed and feeder measurements were recorded approximately every 14-d and at dietary phase changes, first marketing, and conclusion of the trial to determine ADG, ADFI, and F/G.The 3 largest pigs per pen were selected and marketed on d 95 and 98 in barns 1 and 2, respectively, following the routine farm protocol with no carcass data collected on these animals.At the conclusion of the trial, the remaining animals were given a tattoo corresponding to pen number and were transported to a commercial packing facility (JBS Swift and Company; Worthington, MN) for processing and carcass data collection.Carcass measurements taken at the plant included HCW, backfat, percentage carcass lean, and loin depth.Percentage yield was calculated by dividing HCW by mean pen live weight collected at the research facilities prior to transport to harvest facility for the corresponding pen.
Data were analyzed as a randomized complete block design using the GLIMMIX procedure of SAS version 9.4 (SAS Institute, Inc., Cary, NC) with pen as the experimental unit.Weight block was included in the model as a random effect, which also accounted for the barn pigs were housed in.Linear and quadratic interactive effects were evaluated in the statistical model, as well as the main effect of added Cr and linear and quadratic effects of increasing Yucca schidigera.Backfat, loin depth, and percentage lean were adjusted to a common carcass weight using HCW as a covariate.Results were considered significant at P ≤ 0.05 and marginally significant between P > 0.05 and P ≤ 0.10.

Results and Discussion
Proximate analysis of diets did not yield significant differences from formulated values (Table 2).Chromium analysis yielded a significant amount of variability, with analyzed values ranging from 660 to 2,400 ppb.Total Cr content within corn-soybean meal Swine Day 2017 diets can vary significantly, ranging from 750-3,000 ppb. 6Thus, while variable, analyzed values are within reasonable variation.
Increasing Yucca schidigera inclusion in the grower period (65 to 201 lb BW) resulted in a marginally significant (quadratic, P = 0.093; Table 3) decrease, then increase in ADG, with the poorest gain observed in pigs fed diets with 62.5 ppm Yucca schidigera and the best gain observed in pigs fed 125 ppm.This resulted in a marginally significant Cr × Yucca schidigera interaction (linear, P = 0.100) for BW at the end of the grower period with BW being similar across Yucca schidigera treatments when Cr was not included in the diet, but was increased when Yucca schidigera increased from 62.5 to 125 ppm in diets containing Cr. Inclusion of Cr or Yucca schidigera had no effect on (P > 0.10) on ADFI or F/G during the grower period.
During the finishing phase (201 to 272 lb BW), pigs fed added Yucca schidigera had decreased (quadratic, P = 0.018) ADG, with the poorest ADG observed in pigs fed 62.5 ppm Yucca schidigera.There was no evidence of differences (P > 0.10) among pigs for ADFI observed within the finishing period.Feed efficiency worsened (linear, P = 0.034) in pigs fed increasing Yucca schidigera.Added Cr during the finishing period did not influence (P > 0.10) ADG, ADFI, or F/G.
The main effect of added Yucca schidigera on final BW (quadratic, P = 0.012) resulted in pigs fed diets with 62.5 ppm having the lowest final BW.For the overall data, a marginally significant (linear, P = 0.072) Cr × Yucca schidigera interaction was observed for ADG and ADFI, where pigs fed added Yucca schidigera without added Cr did not differ, but when Cr was included, ADG and ADFI increased as Yucca schidigera increased from 62.5 to 125 ppm.This resulted in a marginally significant (linear, P = 0.058) Cr × Yucca schidigera interaction for final BW, where increasing Yucca schidigera without Cr reduced final BW, but when Cr was added, BW increased as Yucca schidigera increased from 62.5 to 125 ppm.Increasing Yucca schidigera supplementation resulted in a marginally significant increase, then decrease (quadratic, P = 0.057) in F/G.Chromium supplementation alone did not influence overall growth performance (P ≥ 0.299).
In summary, supplementation of Cr propionate along with Yucca schidigera led to modest changes in performance with the greatest benefit observed when adding 200 ppb Cr and 125 ppm Yucca schidigera.Adding Cr alone did not influence growth performance or carcass characteristics.With regards to Yucca schidigera level, growth performance was optimized when adding 125 ppm.

Table 3 .
Effects of added Cr propionate and Yucca schidigera on finishing pig growth performance and carcass characteristics 1