Feeding low dietary levels of organic trace minerals improves broiler performance and reduces excretion of minerals in litter.

ABSTRACT

1. This experiment was conducted to evaluate the effect of organic and inorganic trace minerals in diets fed to 1872, one-day-old male Ross 708 broiler chicks. Two sources of supplemental trace minerals (inorganic or organic) and four trace minerals levels (12.5%, 25.0%, 37.5% or 50.0%) plus a positive control containing inorganic minerals at 100% of recommended levels according to Brazilian industry standards, were used in the diets. 2. When analysed with mineral source as the main factor, broilers fed diets containing organic minerals had better feed conversion (FCR) throughout the trial, until 48 d of age (1.754 organic vs. 1.783 inorganic; P < 0.05), improved liveability at 48 d (95.8% organic vs. 93.6% inorganic; P < 0.05) and higher weight gain at 48 d (3.941 kg organic vs. 3.881 kg inorganic; P < 0.05) compared to the inorganic trace mineral diets. At lower dietary inclusion levels (12.5% and 25%) the organic mineral-fed birds had a four-point improvement in FCR (P < 0.05). 3. Feeding organic minerals improved tibial ash at 48 d from 49.5% to 51.25% (P < 0.05). The P and Ca in the tibia at 48 d were significantly (P < 0.05) higher for the birds fed organic minerals (Ca 17.4% vs. 18.7%; P 8.8% vs. 9.4%, respectively). The lower levels of trace minerals in feed reduced the mineral concentration of Zn, Cu and Mn in the faeces and, hence, in the litter (P < 0.05). 4. Feeding organic minerals promoted a small, but statistically significant, drop in pH of breast meat compared to inorganic minerals at 48 d (5.83 vs. 5.86, respectively; P < 0.05). The organic mineral diets reduced drip loss in breast meat compared to inorganic trace mineral supplementation at 32 d of age, but not in older birds (2.46% vs. 3.77%, respectively; P < 0.05). 5. Oxidation status, measured by superoxide dismutase activity in breast muscle at 48 d of age, significantly increased with mineral inclusion levels (P < 0.001), irrespective of source. 6. It was concluded that the use of organic minerals, even at low levels in the diet, is beneficial for broiler performance and reduces the excretion of minerals in litter.