Enhancing diet specification to maximise feed efficiency and production characteristics of the Redbro slow growing...

1. This study assessed the impact of feeding a high nutrient specification (HS) diet, recommended for fast growing broilers and a low nutrient specification (LS) diet, recommended for slow growing broilers, on growth performance variables, including feed intake (FI), weight gain (WG) and feed conversion ratio (FCR) and production characteristics of fast growing Ross 308 broilers and slow growing Redbro broilers.2. As hatched, Ross 308 (n = 210) and Redbro broilers (n = 210) were randomly allocated to 28 floor pens, 14 pens for each genotype and fed experimental diets from 0 to 42 d of age over four feeding phases. Each diet was fed to seven pens of each genotype, following a randomised, blocked, factorial design.3. Growth performance variables were determined for each feeding phase. Excreta were collected during the last 4 d of the study to determine dietary N-corrected apparent metabolisable energy (AMEn) and nutrient retention coefficients. At 42 d of age, one bird per pen was humanely killed and samples were obtained for determination of meat quality variables, jejunal histomorphology and liver triglycerides.4. Feeding the HS diet increased FI (p < 0.05), WG (p < 0.001) and reduced FCR (p < 0.001) in both genotypes from 0 to 42 d compared to feeding the LS diet. Feeding the HS diet increased AMEn intake (p < 0.001). Diet did not affect breast meat quality, except for increasing drip loss in Ross 308 broilers (p < 0.05), nor did it affect breast myopathies, jejunal morphology, or liver function. Therefore, feeding the HS diet, which was formulated to meet the nutrient recommendations for Ross 308, can be a practical strategy to improve the feed efficiency of Redbro broilers.