Determining the Influence of KemTRACE Cr and / or Micro-Aid on Growth Performance and Carcass Composition of Pigs Housed in a Commercial Environment

A study was conducted to determine the interactive effects of chromium propionate (KemTRACE Cr; Kemin Industries Inc., Des Moines, IA) and Micro-Aid (Yucca schidigera-based product; Distributors Processing Inc., Porterville, CA) on growth performance and carcass composition of finishing pigs housed in a commercial environment. There were a total of 1,188 pigs (PIC 337 × 1050; initial BW = 60.3 lb) with 27 pigs/ pen and 11 pens/treatment. Pigs were split by gender upon arrival at the facility, with 5 blocks of each gender and a final mixed sex gender block. Gender blocks were randomly allotted to groups of 4 pen locations within the barn. Diets were corn-soybean meal-dried distillers grains with solubles-based and were fed in 5 phases. All nutrients were formulated to meet or exceed NRC (2012) requirement estimates. Treatments were arranged as a 2 × 2 factorial with main effects of Cr (0 vs 200 ppb) or Micro-Aid (0 vs 62.5 ppm). There were no Cr × Micro-Aid interactions observed for growth or carcass measurements. Overall, ADG and F/G were not influenced by treatment. Adding Cr alone increased (P = 0.048) ADFI, and inclusion of Micro-Aid resulted in a marginally significant increase (P = 0.076) in ADFI. For carcass characteristics, HCW, loin depth, and percentage carcass yield were not influenced by treatment. Backfat depth tended to increase (P = 0.055) and lean percentage was decreased (P = 0.014) when Cr was added to diets. In summary, no synergistic effects were observed from feeding Cr and Micro-Aid in diets fed to finishing pigs housed in a commercial environment. Only marginal differences were observed from adding Cr or Micro-Aid with increased ADFI observed from feeding either. Finally, diets containing added Cr tended to be associated with carcasses having more backfat and less lean suggesting the increased ADFI was not utilized for increased muscle deposition.


and S.S. Dritz 4 Summary
A study was conducted to determine the interactive effects of chromium propionate (KemTRACE Cr; Kemin Industries Inc., Des Moines, IA) and Micro-Aid (Yucca schidigera-based product; Distributors Processing Inc., Porterville, CA) on growth performance and carcass composition of finishing pigs housed in a commercial environment. There were a total of 1,188 pigs (PIC 337 × 1050; initial BW = 60.3 lb) with 27 pigs/ pen and 11 pens/treatment. Pigs were split by gender upon arrival at the facility, with 5 blocks of each gender and a final mixed sex gender block. Gender blocks were randomly allotted to groups of 4 pen locations within the barn. Diets were corn-soybean meal-dried distillers grains with solubles-based and were fed in 5 phases. All nutrients were formulated to meet or exceed NRC (2012) requirement estimates. Treatments were arranged as a 2 × 2 factorial with main effects of Cr (0 vs 200 ppb) or Micro-Aid (0 vs 62.5 ppm). There were no Cr × Micro-Aid interactions observed for growth or carcass measurements. Overall, ADG and F/G were not influenced by treatment. Adding Cr alone increased (P = 0.048) ADFI, and inclusion of Micro-Aid resulted in a marginally significant increase (P = 0.076) in ADFI. For carcass characteristics, HCW, loin depth, and percentage carcass yield were not influenced by treatment. Backfat depth tended to increase (P = 0.055) and lean percentage was decreased (P = 0.014) when Cr was added to diets. In summary, no synergistic effects were observed from feeding Cr and Micro-Aid in diets fed to finishing pigs housed in a commercial environment. Only marginal differences were observed from adding Cr or Micro-Aid with increased ADFI observed from feeding either. Finally, diets containing added Cr tended to be associated

Introduction
Chromium plays a role in carbohydrate, lipid, protein, and nucleic acid metabolism. 5,6 In addition, Cr is associated with insulin sensitivity in the form of a cofactor for glucose tolerance factor. 7 Corn-soybean meal-based diets contain a significant amount of Cr ranging from 1,000 to 3,000 ppb, but much of that is thought to be unavailable to the animal. 8 Recently, a meta-analysis was conducted including 31 different research studies that evaluated Cr supplementation in finishing pig diets. They observed that improvements in growth performance (ADG and F/G) and carcass composition (reduced backfat and increased percentage lean) can be expected with Cr supplementation. 9 Additionally, Yucca schidigera is believed to have a positive impact on gastrointestinal microflora through its saponin characteristics thereby reducing gaseous emissions and potentially improving growth performance; however, limited research exists. 10 Research evaluating the effects of Yucca schidigera supplementation in poultry is available, and would suggest an improvement in F/G. 11 Additionally, research in mice with artificially induced diabetes mellitus indicates a potential reduction of circulating glucose levels when supplemented with Yucca schidigera extract through a potential insulin releasing mechanism from pancreatic β-cells. 12 Research related to the impact of Yucca schidigera on blood metabolites in swine is currently very limited, and there are no data available to determine the interactive effects of Cr and Yucca schidigera when fed to finishing pigs. Therefore, the objective of this experiment was to determine the effects of Cr supplementation with and without Micro-Aid on growth performance and carcass composition of pigs housed in a commercial environment.

Procedures
The Kansas State University Institutional Animal Care and Use Committee approved the protocol used in this experiment. The study was conducted at a commercial research-finishing site in southwest Minnesota. The barn was naturally ventilated and double-curtain-sided. Each pen (18 × 10 feet) was equipped with a 4-hole stainless steel feeder and cup waterer for ad libitum access to feed and water and allowed approximately 6.5 ft 2 /pig. Hourly ambient barn temperatures were recorded throughout the ex- periment (EasyLog Data Loggers; Lascar Electronics, Erie, PA). Feed additions to each individual pen were made and recorded by a robotic feeding system (FeedPro; Feedlogic Corp., Wilmar, MN).
A total of 1,188 pigs (PIC 337 × 1050; initial BW = 60.3 lb) with 27 pigs/pen and 11 pens/treatment were used in a 117-d study. Pens were blocked by BW and were randomly assigned to diets with 27 pigs per pen and 7 pens per treatment. Pigs were split by gender upon arrival at the facility, with 5 blocks of each gender and a final mixed sex gender block. Gender blocks were randomly allotted to groups of 4 pen locations within the barn. Diets were corn-soybean meal-dried distillers grains with solubles-based and were fed in 5 phases. All nutrients were formulated to meet or exceed NRC (2012) requirement estimates (Table 1) Data were analyzed as a randomized complete block design using the GLIMMIX procedure of SAS (SAS Institute, Inc., Cary, NC) with pen as the experimental unit. Block was included in the model as a random effect and accounted for gender, location within barn, and initial BW at the time of allotment. Backfat, loin depth, and percentage lean were adjusted to a common carcass weight for analysis 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
As expected, chemical analysis of complete diets revealed no notable differences among treatments (Tables 2 to 4). The only discrepancy was in Phase 3 when both Cr and Micro-Aid were included and the dietary level of Cr was lower than expected.
There were no Cr × Micro-Aid interactions observed for the entire study (Table 5). For the grower period, added Cr increased (P < 0.028) ADG and ADFI. Added Micro-Aid in the grower period tended to worsen (P = 0.051) F/G. During the finishing period, added Cr tended to increase (P = 0.080) ADFI but worsen F/G. Added Micro-Aid in the finishing period tended to increase (P = 0.088) ADFI. Overall, ADG and F/G were not influenced by treatment. Adding Micro-Aid tended to increase (P = 0.076) and adding Cr increased (P = 0.048) ADFI. For carcass characteristics, HCW, loin depth, and carcass yield were not influenced by treatment. Backfat depth tended to increase (P = 0.055) and lean percentage decreased (P = 0.014) when Cr was added into the diets.  2015) do not appear to be transferable to nursery or finishing pig production, with little research currently available.
In summary, no synergistic effects were observed from feeding Cr and Micro-Aid in diets fed to finishing pigs housed in a commercial environment. Only marginal differences were observed from adding either Cr or Micro-Aid with increased ADFI observed from feeding either Cr or Micro-Aid. Finally, diets containing added Cr tended to be associated with carcasses having more backfat and less lean. This suggests the increased ADFI observed from pigs fed added Cr was not utilized to support lean deposition, but rather was converted to backfat.