Determining the Impact of ByO-Reg + in Diets with or without a Feed Grade Antibiotic on Growth Performance of Nursery Pigs

A total of 717 nursery pigs (PIC C-29 × 28 and PIC L3-1050 × 1040, initially 12.48 ± 0.10 lb) from two consecutive nursery groups were used in a 35-d growth study. The objective was to determine the impact of increasing levels of By-O-Reg+ in diets with or without 50 g/ton Carbadox. By-O-Reg+ is a unique mixture of essential oils primarily based on oregano. It utilizes encapsulation technology to stabilize the essential oils and is suggested to have antimicrobial-like properties. The present study evaluated growth performance of nursery pigs fed 1 of 6 dietary treatments that were arranged as a 2 × 3 factorial with main effects of antibiotic (none vs. 50 g/ton Carbadox) and By-O-Reg+ (0, 1, or 2 lb/ton). Experimental diets were fed for 21 d and then a common diet was fed for the final 14 d. Pens of pigs (5 barrows and 5 gilts) were balanced by initial BW and randomly allotted to treatments, with 12 replications (pens) per treatment. During the period when treatments were fed (d 0 to 21) no interactions were observed between By-O-Reg+ and Carbadox. Increasing By-O-Reg+ decreased, and then increased (quadratic P = 0.016) F/G. Pigs fed diets with Carbadox had improved (P < 0.007) ADG, ADFI, and F/G. From d 21 to 35, when a common diet was fed, pigs previously fed diets with Carbadox had increased (P = 0.007) ADFI. However, an interaction (linear, P = 0.039) was observed with pigs previously fed diets without Carbadox showing decreased ADFI as By-O-Reg+ increased; whereas when pigs were previously fed diets containing Carbadox, ADFI increased as the level of By-O-Reg+ increased. For the overall period (d 0 to 35), an interaction (linear, P = 0.031) was observed for ADFI with pigs fed diets without Carbadox having decreased ADFI as By-O-Reg+ increased; whereas when pigs were fed diets containing Carbadox, ADFI increased with increasing By-O-Reg+. No main effects of By-O-Reg+ were observed for the overall data; however, adding Carbadox for 21 d after weaning improved (P < 0.015) ADG, ADFI, and final BW and tended to improve (P < 0.087) F/G. Overall, this study confirms the benefit of including a feed grade medication in nursery pig diets to improve growth performance. Increasing By-O-Reg+ in diets elicited few changes in performance, but during the test period the pigs fed 1 lb/ton of By-O-Reg+ had better F/G than those fed none or the 2 lb/ton of By-O-Reg+. More research is needed to confirm if 1 lb/ ton inclusion of By-O-Reg+ is the appropriate dose to elicit the best response.


Summary
A total of 717 nursery pigs (PIC C-29 × 28 and PIC L3-1050 × 1040, initially 12.48 ± 0.10 lb) from two consecutive nursery groups were used in a 35-d growth study.The objective was to determine the impact of increasing levels of By-O-Reg+ in diets with or without 50 g/ton Carbadox.By-O-Reg+ is a unique mixture of essential oils primarily based on oregano.It utilizes encapsulation technology to stabilize the essential oils and is suggested to have antimicrobial-like properties.The present study evaluated growth performance of nursery pigs fed 1 of 6 dietary treatments that were arranged as a 2 × 3 factorial with main effects of antibiotic (none vs. 50 g/ton Carbadox) and By-O-Reg+ (0, 1, or 2 lb/ton).Experimental diets were fed for 21 d and then a common diet was fed for the final 14 d.Pens of pigs (5 barrows and 5 gilts) were balanced by initial BW and randomly allotted to treatments, with 12 replications (pens) per treatment.During the period when treatments were fed (d 0 to 21) no interactions were observed between By-O-Reg+ and Carbadox.Increasing By-O-Reg+ decreased, and then increased (quadratic P = 0.016) F/G.Pigs fed diets with Carbadox had improved (P < 0.007) ADG, ADFI, and F/G.From d 21 to 35, when a common diet was fed, pigs previously fed diets with Carbadox had increased (P = 0.007) ADFI.However, an interaction (linear, P = 0.A new oregano-based product has been introduced to the market.By-O-Reg+ is a unique source of oregano that utilizes encapsulation technology to protect the carvacrol (the primary beneficial phenolic compound found in oregano) from volatilization or binding to other components in the feed.This is suggested to protect and allow the essential oil to be released into the lower intestinal tract where it is most effective.While some studies have been conducted with poultry and aquaculture, the only swinerelated studies have been conducted in sows, so the impact of By-O-Reg+ on growth performance of newly weaned pigs is unknown.The objective of this experiment is to determine the impact of By-O-Reg+ in diets with or without feed grade antibiotics on growth performance of weaned pigs.

Procedures
The Kansas State University Institutional Animal Care and Use Committee approved the protocol for this experiment.The study was conducted at the Cooperative Research Farm's Swine Research Nursery (Sycamore, OH), which is owned and managed by Kalmbach Feeds, Inc.
A total of 717 pigs (PIC C-29 × 28 and PIC L3-1050 × 1040) from two consecutive nursery groups (group 1 initially 12.8 ± 0.10 lb and group 2 initially 12.2 ± 0.06 lb) were used in a 35-d growth study.Pens of pigs (5 barrows and 5 gilts) were balanced by initial BW and randomly allotted to treatments with 6 replications (pens) per treatment in each group for a total of 12 replications per treatment.Each pen had slatted metal floors and was equipped with a 4-hole stainless steel feeder and one nipple-cup waterer for ad libitum access to feed and water.To better reflect the increased challenge of rearing pigs in a commercial environment, rooms were not washed before the experiments to increase bacteria load.Group 1 had two previous sets of pigs; group 2 had 1 previous set of pigs.Dietary treatments were offered immediately after weaning and were organized in a 2 × 3 factorial with main effects of antibiotic (none vs. 50 g/ton of Carbadox) and By-O-Reg+ (0, 1, or 2 lb/ton).Treatment diets (Tables 1 and 2) were fed in pellet form in 2 phases with phase 1 fed from d 0 to 7 and phase 2 fed from d 7 to 21 with Carbadox and/or By-O-Reg+ added at the expense of corn.A common phase 3 diet (Table 3) that contained no Carbadox or By-O-Reg+ was fed in meal form d 21 to 35.Feed was manufactured at the Kalmbach Feeds feed mill.Multiple feed samples were collected at the feeder during each phase and analyzed for CP, ADF, NDF, crude fiber, ether extract, Ca, and P (Ward Laboratories, Inc., Kearney, NE, Table 4).Pig weight and feed disappearance were measured on d 0, 7, 14, 21, 28, and 35 to determine ADG, ADFI, and F/G.
Data were analyzed using the PROC MIXED procedures of SAS (SAS Institute Inc., Cary, NC) in a randomized design with pen serving as the experimental unit and experiment as the random blocking factor.The main effects of By-O-Reg+ and Carbadox, and their interactions, were tested using preplanned contrasts.Linear and quadratic contrasts were used to evaluate the effects of By-O-Reg+ on growth performance.Results were considered significant at P ≤ 0.05 and a trend at P ≤ 0.10.

Results and Discussion
Body weight, ADG, ADFI, and feed efficiency data are shown in Tables 3 4 Mecadox 10 (Phibro Animal Health, Teaneck, NJ) containing Carbadox at 10 g/lb, was added to the antibiotic treatment groups at 5 lb/ton at the expense of corn in the control diet to form the antibiotic treatment in Phases 1 and 2.
5 By-O-Reg+ (Advanced Ag Products, Hudson, SD) was included at 1 or 2 lb/ton at the expense of corn in the control diets to form the By-O-Reg+ treatments fed in phases 1 and 2.
Agricultural Experiment Station and Cooperative Extension Service 1 Determining the Impact of By-O-Reg+ 1 in Diets with or without a Feed Grade Antibiotic on Growth Performance of Nursery Pigs 2 L. L. Thomas, J. C. Woodworth, R. D. Goodband, J. M. DeRouchey, M. D. Tokach, and S. S. Dritz

Table 1 .
Diet composition (as-fed basis) (interactive means) and 4 (main effects).From d 0 to 21, no interactions were observed between pigs fed By-O-Reg+ or Carbadox.Feed efficiency of pigs fed By-O-Reg+ decreased, and then increased (quadratic, P = 0.016), as By-O-Reg+ increased.Pigs fed diets with Carbadox had improved (P ≤ 0.007) ADG, ADFI, and F/G.From d 21 to 35, when a common diet was fed, pigs previously fed diets with Carbadox had improved (P = 0.007) ADFI.An interaction (linear, P = 0.039) was observed, with pigs previously fed diets without Carbadox showing decreased ADFI as By-O-Reg+ increased; whereas when pigs were previously fed diets containing antibiotics, the ADFI increased as the level of By-O-Reg+ increased.For the overall data (d 0 to 35), an interaction (linear, P = 0.031) was observed for ADFI, with pigs fed diets without Carbadox exhibiting decreased ADFI as By-O-Reg+ increased; however, when pigs were fed diets containing Carbadox, ADFI increased as By-O-Reg+ increased.No main effects of By-O-Reg+ were observed for the overall study; however, adding Carbadox improved (P < 0.015) ADG, ADFI, and final BW, and tended to improve (P < 0.087) F/G.observed to stimulate ADFI in diets containing Carbadox.Additional research should be conducted to confirm if the greatest By-O-Reg+ benefit occurs when feed grade antibiotics are simultaneously present in the diet. 3Phase 3 was a common diet that did not contain antibiotic or By-O-Reg+, fed from d 21 to 35.

Table 2 .
Chemical analysis of diets (as-fed basis) 1