Evaluating Effects of Copper Sources in Nursery Pig Diets and Phytase Inclusion and Diet Interactions on Water Usage in Growing and Finishing Pigs

In modern swine production, nutritional strategies that optimize growth performance, resource utilization, and carcass quality are essential. Three independent trials were conducted to evaluate how dietary modifications involving copper (Cu) sources, phytase inclusion, and amino acid reformulation affect nursery and grow-finish pigs. The first trial assessed the effects of three different Cu sources on nursery pig growth performance. A total of 1,145 pigs (5.9 ± 1.3 kg BW) were assigned to one of four dietary treatments: control, tri-basic Cu chloride source #1 (TBCC1), Cu chelate (cCu), or tri-basic Cu chloride source #2 (TBCC2), each providing 150 ppm of Cu. Over 49 days, pigs fed any Cu-supplemented diet exhibited improved body weight (BW), average daily gain (ADG), and feed efficiency (G:F) compared to the control. Minimal performance differences were observed among Cu sources, indicating comparable efficacy across treatments. The second trial investigated effects of a superdose, inclusion at levels substantially exceeding standard recommendations to maximize nutrient release, of phytase (i.e. 2000 FTU) and corn dried distillers’ grains with solubles (cDDGS) on water usage and growth performance in grow-finish pigs. A total of 1,116 pigs (27 ± 3 kg BW) were assigned to one of four diets in a 2×2 factorial arrangement with or without phytase or cDDGS. Phytase and cDDGS independently increased water usage. While both components elevated average daily water usage (ADWU), diets without phytase or cDDGS resulted in greater ADG. Feed efficiency (G:F) was improved with phytase from day 21 to 49. These results indicate that while phytase and cDDGS inclusion independently increased water usage and phytase positively influenced feed efficiency, they did not significantly affect final BW. The third trial examined how two levels of phytase inclusion and accounting for AAs uplift with the higher phytase inclusion influenced ADWU, performance, and hot carcass weight (HCW) of finisher pigs. A total of 1,092 grow-finish pigs (53 ± 5 kg BW) were fed one of four diets: control, control + 600 FYT phytase, control + 1000 FYT phytase, or 1000 FYT phytase + amino acid correction (AACorr). A quadratic response in ADWU was observed, as ADWU increased from the control to 600 FYT, declined slightly at 1000 FYT, and increased further when amino acid correction was applied at 1000 FYT. However, no significant differences were found among treatments for BW, ADG, ADFI, G:F, or HCW, indicating that while phytase and amino acid reformulation influenced water usage, their impact on growth and carcass characteristics was minimal. Together, these studies demonstrate that supranutritional Cu enhanced nursery pig performance regardless of source, while phytase inclusion and cDDGS addition independently increased daily water intake, and amino acid correction with high phytase further elevated water usage in grow-finish pigs, with minimal impact on growth or hot carcass weight.