Effects of Supplemental Chromium Source and Concentration on Growth Performance, Carcass Traits, and Meat Quality of Broilers Under Heat Stress Conditions.

The objective of this study was to investigate the effects of dietary supplemental chromium (Cr) on growth performance, carcass traits, and meat quality of broilers reared under heat stress. A total of 252 1-d-old Cobb 500 commercial female broilers were randomly allotted by body weight (BW) to one of six replicate cages (six broilers per cage) for each of seven treatments in a completely randomized design involving a 2 × 3 factorial arrangement of treatments with three Cr sources (Cr propionate, CrPro; Cr picolinate, CrPic; Cr chloride, CrCl3) and two concentrations of added Cr (0.4, or 2.0 mg of Cr/kg) plus a Cr-unsupplemented control group. Feed and distilled-deionized water were available ad libitum for an experimental phase of 42 days. For induction of heat stress, the house temperature was set at 33 ± 2 °C from 15 to 42 days of age. Results showed that birds supplemented with Cr, regardless of Cr source, had increased ADG (P = 0.032) than controls. Birds fed 2.0 mg Cr/kg diet had greater ADG (P = 0.005) than birds fed 0.4 mg Cr/kg diet. Compared to controls, birds fed with Cr had greater dressing percentage (P = 0.021). Percentage of abdominal fat decreased (P = 0.013), whereas, breast intramuscular fat (IMF) remained unaffected (P = 0.147) in Cr supplemented vs control broilers. Broilers supplemented Cr had decreased b* values of meat color (P = 0.042) in breast muscle. B*values were also lesser (P = 0.049) in birds fed CrPro than birds supplemented with CrCl3 or CrPic. Regardless of Cr source, the percentage of cooking loss was decreased (P = 0.025) with Cr supplementation in breast muscle when compared to controls. Results from this study indicate that Cr supplementation, independent of its source, could promote growth and improve carcass traits and meat quality of broilers under heat stress conditions. Chromium propionate seems to have greater beneficial effects on meat color in comparison with CrPic and CrCl3.