Effects of dietary L-carnitine supplementation and protein level on performance and degree of meatness and fatness of broilers.

Feeding high-protein diets to broilers is a known means for improving performance and carcass composition and quality, however, the combined effects of dietary protein (CP) level concurrent with L-carnitine (CN) supplementation are not known. Performance and carcass traits of broilers fed CN-supplemented diets of different CP-levels were studied from 18 to 53 days of age. Three isocaloric diets containing 18, 20 or 22% CP were formulated, with or without added CN (50 mg/kg), and used. Apart from CP level, supplemental CN attained significantly higher body weight gain (BWG) and feed conversion (FC), means of BWG were 351 vs. 332 and 371 vs. 353 g, and those of FC were 1.25 vs. 1.33 and 1.73 vs. 1.84 for the first and second week of the experimental period, respectively. Amount and percentage of abdominal fat and ether extract (EE) contents of breast meat of 53-day-old broilers were significantly reduced (means of AF were 43.5 vs. 51.5 g, equivalent to 1.98 vs. 2.39%, those of EE were 1.82 vs. 2.24%) in response to CN supplementation. A significant interaction between added CN and CP level was noted on BWG and FC of broilers from 18 to 32 days of age.