The effects of zinc source and supplemental copper on growth performance, carcass characteristics, and morbidity and mortality of growing-finishing pigs raised under commercial conditions

Schmitt, Rachel Loren

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Description

Title

The effects of zinc source and supplemental copper on growth performance, carcass characteristics, and morbidity and mortality of growing-finishing pigs raised under commercial conditions

Author(s)

Schmitt, Rachel Loren

Issue Date

2018-07-10

Director of Research (if dissertation) or Advisor (if thesis)

Ellis, Michael

Department of Study

Animal Sciences

Discipline

Animal Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Swine
• nutrition
• zinc

Abstract

Zinc hydroxychloride and tribasic copper chloride are relatively new mineral sources that are claimed to have improved bioavailability relative to commonly used zinc sources such as zinc oxide. Both sources were evaluated in two studies that were carried out to determine the effects of zinc source and supplemental copper on growth performance, carcass characteristics, and morbidity and mortality of growing-finishing pigs raised under commercial conditions. In both studies, the zinc sources were included at levels to marginally exceed the requirements of growing-finishing pigs suggested by NRC (2012); the copper source, which was only included in the first study, was included to provide pharmacological levels of copper. Study 1 was carried out using a randomized complete block design (blocking factor was date of start on test) to compare 4 treatments: Trt. 1: Control [zinc oxide (assuming 65% bioavailability) + supplemental copper (tribasic copper chloride at 150 ppm)]; Trt. 2: [zinc hydroxychloride (assuming 65% bioavailability) + supplemental copper (tribasic copper chloride at 150 ppm)]; Trt. 3: [zinc hydroxychloride (assuming 100% Bioavailability) + supplemental copper (tribasic copper chloride at 150 ppm)]; and Trt. 4: As Treatment 1 without supplemental copper. The pigs used for Study 2 had previously been allotted to additional experimental treatments that were independent of those used in the current study. Consequently, Study 2 used a split-plot design with the main plot being the additional experimental treatments and the subplot being the two zinc treatments: Trt. 1: Control (zinc oxide assuming 65% bioavailability) and Trt. 2: zinc hydroxychloride (assuming 100% bioavailability). A total of 2,040 (27 replicates) and 2,888 (66 replicates) commercial crossbred barrows and gilts (housed in single-sex groups of 22 at a floor space of 0.59 m2/pig) were used in Studies 1 and 2, respectively. Studies 1 and 2 were carried out from 47.0 ± 5.1 kg to 127.1 ± 3.9 kg body weight and from 41.9 ± 1.7 kg to 132.0 ± 4.4 kg body weight, respectively. There were 5 dietary phases in Study 1 and 3 dietary phases in Study 2. Diets were formulated to a constant standardized ileal digestible lysine:ME ratio within phase and to meet or exceed nutrient requirements suggested by NRC (2012). Ractopamine hydrochloride (7.5 ppm) was included in the final dietary phase in all dietary treatments for both studies. Pen weights and pen feed intakes were collected every 2 and 3 weeks for Studies 1 and 2, respectively, and used to calculate ADG, ADFI and G:F. At the end of the study, pigs were sent to a commercial facility for harvest and collection of carcass measurements. For both studies, the pen of pigs was the experimental unit; data were analyzed using the PROC MIXED procedure of SAS (v. 9.2; SAS Inst. Inc., Cary, NC) with the model accounting for the fixed effects of treatment and the random effects of replicate. Results from Study 1 showed that Trt. 3 had greater (P = 0.04) live weight ADG compared to Trt. 1, with Trt. 2 being intermediate and not different (P = 0.39) than the other 2 treatments (0.97, 0.98, 0.99 kg for Trt. 1, 2, and 3 respectively; SEM 0.03). Treatment 3 also had greater (P = 0.03) live weight G:F than Trt. 2, but not (P = 0.16) Trt. 1 (0.362, 0.361, 0.366 for Trt. 1, 2, and 3 respectively; SEM 0.0024). Adding supplemental copper to the diet had no effect (P > 0.05) on live weight ADG, ADFI, or G:F, however, carcass weight ADG was numerically increased (P = 0.07) and carcass weight G:F was significantly improved (P = 0.03) for Trt. 4 compared to Trt.1. In Study 2, pigs fed diets supplemented with zinc hydroxychloride (Trt. 2) had lower (P < 0.05) overall ADG, on both a live and carcass weight basis (1.021 and 1.002, and 0.821 and 0.780, for Trt. 1 and 2, respectively), and ADFI, (2.62 and 2.59 for Trt. 1 and 2, respectively), but similar (P > 0.05) live weight and carcass weight G:F compared to those fed diets containing zinc oxide (Trt. 1). There was no effect (P > 0.05) of zinc source on carcass measurements or morbidity and mortality in either study. The results for Study 1 suggested comparable or small improvements in growth performance from using zinc hydroxychloride (assumed bioavailability 100%; Trt. 3) compared to zinc oxide. However, the opposite was evident in Study 2. Study 1 also suggested small improvements in growth performance from feeding high levels of copper to growing-finishing pigs. Further research is needed to clearly establish the advantage, if any, of replacing zinc oxide with zinc hydroxychloride and of including high levels of copper as tribasic copper chloride in diets for growing-finishing pigs.

Graduation Semester

2018-08

Type of Resource

text

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Copyright 2018 Rachel Schmitt

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