Nutritional supplements provide potential feed savings.

University of Illinois researchers report finding an additional performance response to organic copper when zinc oxide is present in swine diets. The researchers estimate the benefit from adding the organic copper product to a diet that is high in zinc oxide (ZnO) could add up to $0.19 to $0.44/pig, depending upon feed prices.

Using pharmacological levels of either copper or zinc as non-antibiotic growth promoters in weaning diets is a common practice. Adding an inorganic source of copper to a diet containing zinc oxide has not shown any additional pig performance benefits, according to previous research. However, the additive benefits of zinc oxide and organic copper have not been tested.

Testing Additive Benefits

Previous University of Illinois research suggests there are benefits to be gained by supplementing copper at 100 ppm from an organic copper amino acid complex (Availa-Cu, Zinpro Corp. CuAA), or supplementing copper at 250 ppm from inorganic copper sulfate (CuSO4). The copper seems to have an additive effect on the pig's performance after weaning when fed with zinc oxide (3,000 ppm Zn).

Over a six-week period, copper supplementation improved the daily gain by 47 g/pig in the absence of zinc, and by 31 g/pig in addition to the zinc oxide benefit.

Moreover, the cumulative effect of CuAA on the growth rate was superior to that of copper sulfate until the fourth week postweaning, according to researchers.

Farm Trial

Another experiment was conducted at a commercial farm under typical production conditions that present health challenges. Pre-starter diets were supplemented in a six-week trial with 100 ppm copper from CuAA, or during the first two weeks only with 3,000 ppm zinc, from zinc oxide or both copper and zinc supplementation.

The experiment included a four-stage feeding program with decreasing diet complexity during the six weeks, with 1, 1, 2, and 2 weeks per each phase. Diets were typical of those used in commercial production. Phases 1 and 2 were supplied in mini-pellet form, and the other diets were fed in meal form. No antibiotics were used in any of the diets; however, individual antibiotic therapy was administered as needed.

During the first week postweaning, daily growth rate was improved by either CuAA or zinc oxide supplementation.

In addition, CuAA increased daily growth rate 8% when added to a diet containing zinc oxide. Daily feed intake was increased by either CuAA or zinc oxide supplementation, but adding both minerals to the diet did not result in additional benefits in this first week. These results are shown in Table 1.

Over the six-week period, the daily gain was improved 13% by CuAA, 20% by zinc oxide and 26% when both minerals were added to the diet. Daily feed intake response exhibited the same pattern.

Zinc Improves Health

An unusual Escherichia coli diarrhea outbreak caused a high rate of pigs to be removed due to poor health and mortality. This rate was dramatically reduced by zinc oxide effect: 17.1% vs. 6.6% over the six weeks.

The diarrhea outbreak started at the end of the first week and peaked during the second week. It appears that most of the pigs were probably challenged during the time zinc oxide was fed, but the protective effect of zinc oxide remained over the six weeks.

Organic Copper, Zinc Synergy

These data show there is an additional response to dietary CuAA on pig performance when zinc oxide is present in the diet. This response may occur because of a perceived systemic effect of copper supplementation, and the high bioavailability of this organic source of copper.

The researchers expect the results of this research will influence practicing nutritionists' decisions about whether to add organic copper to the diets in addition to zinc.

Researchers: James Pettigrew and Victor Perez-Mendoza, University of Illinois at Urbana-Champaign. Contact Perez-Mendoza at (217) 333-9749.

Table 1. Pigs' Performance after Weaning with Dietary Supplementation of Either Organic Copper (Cu) (100 ppm Cu), Zinc (ZnO) (3,000 ppm Zn), or Both
Treatments Week 1 Overall Pigs removed, %
Gain, g/d Intake, g/d Gain, g/d Intake, g/d
Control 60 106 250 401 16
CuAA* 95 130 283 445 18
ZnO 110 134 300 459 6
ZnO+CuAA 119 132 315 481 7
Standard error 9.9 6.5 12.3 17.1 2.7
*An organic copper amino acid complex, Availa-Cu or CUAA from Zinpro Corp.

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