Effect of chelated copper on gut health in broilers

Copper (Cu) has been widely used at pharmacological levels (e.g., 125 ppm) as growth promoter in poultry. However, the mechanism by which high levels of Cu promote growth remains to be determined. It is commonly recognized that Cu exerts anti-microbial effects in the gut but there is not much direct and consistent data showing that Cu alters the population of bacterial species in birds. The objective of this study was to understand the mechanism by which Cu methionine hydroxy-analogue chelate (Cu-MHAC) (MINTREX® Cu, Novus International, Inc.) improves gut health in broilers in comparison to CuSO4. Wheat-barley-soybean meal based diets were formulated to meet or exceed nutrient needs. Cu-MHAC was supplemented at 15 ppm (M15), or 30 ppm (M30) in final diets. CuSO4 was supplemented at 125 ppm (ITM). Supplemental levels of Zn (100 ppm), Mn (90 ppm), Fe (40 ppm), I (1.25 ppm), and Se (0.3 ppm) from inorganic sources were equal among treatments. Each diet was fed to 9 replicate pens of 10 Ross 308 male broilers. Data were analyzed by one-way ANOVA. M15 improved (P < 0.04) performance index during grower phase (d 15-28) and d 28 cumulative performance index compared to ITM. Compared to ITM, M15 reduced the thickness of muscular layer of duodenum (P < 0.1), jejunum (P < 0.004) and ileum (P < 0.001), and crypt depth in ileum (P < 0.03); M30 reduced the muscular layer thickness of duodenum (P < 0.008) and jejunum (P < 0.1) in birds of 42 d of age. These results indicate that Cu-MHAC improved gut morphology and likely reduced the needs of energy and nutrients to maintain gut barrier function. M30 reduced (P < 0.05) total bacteria in cecum, both M15 (P < 0.03) and M30 (P < 0.06) reduced the ratio of Firmicutes to total bacteria in cecum compared to ITM in birds of 42 d of age. Taken together, Cu-MHAC improved gut health of broilers by maintaining better gut structural integrity and shifting the gastrointestinal microbiota to more beneficial microflora, which led to better growth performance index.

 

Keywords: Chelated copper, gut morphometry, gut health, microbiota.