Different copper sources and levels affect growth performance, copper content, carcass characteristics, intestinal microorganism and metabolism of finishing pigs

Abstract

Copper (Cu) is an essential trace element in the production of swine. This study was conducted to investigate the effect of 3 different sources of Cu on growth performance, Cu metabolism, and intestinal microorganisms of finishing pigs, so as to estimate the bioavailability of the 3 sources for pigs. A total of 42 male finishing pigs (88.74 ± 5.74 kg) were randomly allocated to 7 treatments. The factors were 3 sources (CuSO 4 , Cu-glycine, Cu-proteinate) and 2 levels (5 and 20 mg/kg) of Cu, plus one negative control treatment (0 mg/kg added Cu level) for the entire 28-d experiment. The average daily gain (ADG) and feed to gain ratio (F:G) both increased when Cu was added. The Cu level in liver, bile, kidney, serum, lung, urine and feces rose ( P < 0.001) with increasing dietary Cu level regardless of the source. Meanwhile, pigs receiving organic Cu (glycinate or proteinate) retained more Cu and excreted less Cu than those receiving inorganic Cu (CuSO 4 ), which showed that organic forms were more bioavailable. At the transcriptional level, changes in the level and source of dietary Cu resulted in modulation of transporters. In the jejunal mucosa, import transporter high affinity copper uptake protein 1 ( CTR1 ) and export transporter ATPase copper transporting alpha ( ATP7A ) in supplemental Cu treatments were down-regulated compared to the control. Also, peptide transporter 1 ( PepT1 ) and lanine-serine-cysteine transporter, type-2 ( ASCT2 ) were significantly ( P < 0.01) up-regulated in 20 mg/kg Cu-proteinate and Cu-glycinate treatments, respectively. Microbial diversity was lowest in the 20 mg/kg CuSO 4 treatment, and the ratio of Firmicutes to Bacteroidetes was higher in added Cu treatments, especially Cu-glycinate treatment. These results indicate that uptake of different Cu forms is facilitated by different transporters and transport mechanisms, and compared with inorganic Cu, organic Cu provides benefits to intestinal microflora and reduces Cu excretion.

Effects of dietary copper sources and levels on growth performance, copper digestibility, fecal and serum mineral characteristics in growing pigs

“…It has been established previously that weaned pigs fed an organic Cu source showed greater gain and feed efficiency compared with that pigs fed an inorganic Cu source [ 3 , 5 , 6 ]. Furthermore, although Zhao et al [ 3 ] reported that a relatively lower organic Cu (CuHMB) source increases the ADG and carcass weight of finishing pigs compared with that in pigs fed inorganic Cu source [ 3 ], others have reported that the Cu source did not affect weight gain during the growing and finishing phases [ 4 , 7 ]. Overall, both organic and inorganic Cu sources may have positive effects on growth performance in the overall growth stage of pigs.…”

“…In the body, Cu is mainly stored in the liver and kidneys, and the Cu content in these organs contributes to the Cu concentration in the blood [ 19 ]. It has been reported that liver Cu concentration is high in pigs fed a Cu-rich diet, and excessive Cu accumulation can lead to its leakage into the circulatory system [ 4 , 12 ]. The blood Cu concentrations in weaned and finishing pigs are reported to have increased after the intake of dietary Cu [ 4 , 6 ].…”

Latent Benefits and Toxicity Risks Transmission Chain of High Dietary Copper along the Livestock–Environment–Plant–Human Health Axis and Microbial Homeostasis: A Review

“…Moreover, different Cu sources also affect the bioavailability in livestock diets. Several studies have demonstrated that organic Cu, such as Cu–glycine and Cu–proteinate, has greater bioavailability compared to inorganic Cu; , for example, Wen et al reported that organic Cu provides benefits to intestinal microbiota and reduces Cu excretion in pigs compared with inorganic Cu. Li et al also found that organic Cu is less toxic and has a higher absorption efficiency compared with inorganic Cu.…”

“…High Cu improves the environmental adaptability of soil microorganisms and induces toxicity in agricultural soils . A study also indicated that high-Cu diets can alter the gut microenvironment and impact the composition and abundance of bacteria in livestock; for example, dietary high Cu decreases the intestinal microbial diversity but increases the ratio of Firmicutes to Bacteroidetes in pigs . Dietary Cu also enhances ruminal microbial fermentation in ruminants .…”

“…15 A study also indicated that high-Cu diets can alter the gut microenvironment and impact the composition and abundance of bacteria in livestock; 16 for example, dietary high Cu decreases the intestinal microbial diversity but increases the ratio of Firmicutes to Bacteroidetes in pigs. 17 fermentation in ruminants. 18 In addition, Cu can cause poor intestinal permeability and disorders of the intestinal microbiota in humans, thus developing metabolic and autoimmune diseases risks, 19 such as type I diabetes and multiple sclerosis.…”