Effect of different levels of copper on growth performance and cecal ecosystem of newly weaned piglets

The current study aimed to investigate the effects of different levels of copper sulfate on the growth performance and cecal ecosystem in newly weaned piglets. One hundred piglets weaned at 28±2 d were randomly allocated to 4 treatments with 5 replicates of 5 piglets each. Piglets received for 28 d the base diet with i) no addition (control) or with copper addition (from copper sulfate) at ii) 100, iii) 175, and iv) 250 mg/kg1. On day 21, twenty piglets were randomly selected (one from each replicate) to slaughter and investigate the population and diversity of cecal microorganisms. The results showed that the diets containing 175 and 250 mg/kg1 copper improved the average daily gain (ADG) by 51% and 60% and decreased the feed to gain ratio (F/G) by 21% and 16%, respectively. Adding 175 or 250 mg/kg1 copper improved crude protein, ether extract, calcium and phosphorus digestibility. Viable counts of Enterobacteriaceae and Lactobacilli in cecum tended to be reduced, while the concentrations of cecal volatile fatty acids (VFA) were increased in pigs fed diet supplemented as copper level increased. Polymerase chain reaction (PCR) results showed that adding 175 or 250 mg/kg1 copper reduced the lactobacilli in cecum. Denaturing gradient gel electrophore-sis (DGGE) maps showed that band numbers and intensity of cecal bacterial 16S rDNA decreased as the copper levels increased. The results suggested that the effects of high dietary copper on microflora and their activities and metabolic products might contribute to the intestinal health and result in improved growth performance.