Water-Soluble Zinc Improves Pig Growth Performance, Research Says

( National Pork Board and the Pork Checkoff )

“The pork industry puts a premium on gain and days to market, and an increase in gain and exit weight from the nursery has profound implications through finishing,” says Wesley Schweer, swine nutritionist with Zinpro Corporation. Pigs reaching market weight one to three days sooner results in lower feed costs, reduced labor expenses and more efficient throughput.

Unfortunately, weaning is a stressful time for piglets and can result in the pigs not eating for 24 to 48 hours, even up to 72 hours after weaning. Generally, a pig will drink before it eats in the nursery. 

“This creates an opportunity to provide nutrients to aid with piglet gut health, immunity and ultimately improve performance via the water in the nursery,” Schweer says.

Previous research shows that supplementing a water-soluble zinc via drinking water (0 to 80 mg/L) to nursery pigs improved average daily gain (ADG) and gain to feed ratio (G:F) in a dose-dependent manner. Pigs receiving the 40 ppm of the water-soluble zinc amino acid complex were 2.89 pounds heavier at day 42 than pigs fed the control diet.

Impact of Water-Soluble Zinc on Pig Growth
Researchers took this a step further in a recent trial, evaluating the efficacy of higher titrated levels of this water-soluble zinc amino acid complex Zinpro’s “TruCare LQ Zn” on growth performance. In the study, 280 crossbred pigs (5.5 kg BW) from seven different sow farms were randomly allotted to four water treatments. The water treatments were 0, 40, 80 and 160 mg Zn/L of water. 

Pigs were fed in four dietary phases with corn-soybean meal-based diets: Phase 1 and 2 (2,500 and 1,750 mg Zn as ZnO/kg; d 1-7 and 7-14, respectively) and Phase 3 and 4 (200 mg Cu as CuSO4/kg; d 14-23 and 23-42, respectively).

Pigs and feeders were weighed weekly to determine ADG, average daily feed intake (ADFI) and G:F. Water meters were used to record and calculate water disappearance and zinc intake. Data were analyzed as a randomized complete block design. 

Water zinc intake and total zinc intake increased linearly with increasing zinc. From day 0-14 when high dietary zinc was fed, there were no differences in ADG, ADFI, or G:F. However, from day 14-42 when basal levels of zinc were fed, quadratic improvements in ADG and G:F were observed with increasing zinc via water. Similarly, for day 0-42, ADG, G:F and average ending weight improved quadratically with increasing zinc. In conclusion, supplementing with the water-soluble zinc amino acid complex resulted in improvements in ADG and G:F for nursery pigs.

A Look at Immune Outcomes
One of the major challenges of a piglet going without feed is the environmental and physiological stress this causes, creating more opportunities for opportunistic bacteria to disrupt gut health, Schweer says.

In a second study with the University of Minnesota, researchers looked at how this water-soluble zinc amino acid complex impacts immune outcomes, specifically when challenged with Lawsonia intracellularis (LI). 

Pigs were fed one of three diets during the study. Group 1 received 125 ppm of zinc sulfate in the feed (control diet). Group 2 received 125 ppm of total zinc with 50 ppm from Availa Zn in the feed. Group 3 received 125 ppm of zinc sulfate in the feed and 40 ppm of TruCare LQ Zn in the water. 
After 21 days on these diets, pigs were exposed to a subclinical LI. Pigs were serial sacrificed at 14, 21 and 28 days post-inoculation to measure the host immune response to the challenge.

They found that pigs receiving the water-soluble zinc amino acid complex developed antibodies up to one week earlier than challenged pigs receiving zinc sulfate.

T-cell counts in the infected crypts of the ileum of pigs fed the control diet remained suppressed at 21 days post-inoculation compared to pigs in group 2 who showed increased T cell counts at 14 days post-inoculation.

In addition, at 28 days post-inoculation, pigs receiving the water-soluble zinc amino acid complex had fewer intestinal lesions caused by LI and the lesions were less severe than pigs receiving nutritional levels of zinc sulfate.

“Since weaned pigs generally consume water before feed, incorporating TruCare LQ Zn into the water helps support health outcomes in the high-stress nursery phase of production, which can also be beneficial through the finisher phase,” Schweer says.

The study, “Effects of titrated levels of water soluble zinc amino acid complex on growth performance of nursery pigs,” will be presented at the 2019 American Society of Animal Science Annual Meeting and Trade Show in Austin, Texas, in July by Pornpim Aparachita. Other authors of the study include Scott Carter, Afton Sawyer and Jared Harshman of Oklahoma State University; and Zach Rambo and Terry Ward of Zinpro Corporation in Eden Prairie, Minn.

More from Farm Journal's PORK:


Put Up Hurdles to Keep Swine Diseases Out

Determining the Risk of African Swine Fever in Vitamins

PEDV: Hysteria is Gone, but Disease Isn’t