The effects of growth rate on leg morphology and tibia breaking strength, mineral density, mineral content, and bone ash in broilers

Abstract

Fast-growing broilers are especially susceptible to bone abnormalities, causing major problems for broiler producers. The cortical bones of fast-growing broilers are highly porous, which may lead to leg deformities. Leg problems were investigated in 6-wk-old Arkansas randombred broilers. Body weight was measured at hatch and at 6 wk. There were 8 different settings of approximately 450 eggs each. Two subpopulations, slow-growing (SG; bottom quarter, n=511) and fast-growing (FG; top quarter, n=545), were created from a randombred population based on their growth rate from hatch until 6 wk of age. At 6 wk of age, the broilers were processed and chilled at 4°C overnight before deboning. Shank (78.27±8.06 g), drum stick (190.92±16.91 g), and thigh weights (233.88±22.66 g) of FG broilers were higher than those of SG broilers (54.39±6.86, 135.39±15.45, and 168.50±21.13 g, respectivly; P<0.001). Tibia weights (15.36±2.28 g) of FG broilers were also greater than those of SG broilers (11.23±1.81 g; P<0.001). Shank length (81.50±4.71 g) and tibia length (104.34±4.45 mm) of FG broilers were longer than those of SG broilers (71.88±4.66 and 95.98±4.85 mm, respectively; P<0.001). Shank diameter (11.59±1.60 mm) and tibia diameter (8.20±0.62 mm) of FG broilers were wider than those of SG broilers (9.45±1.74, 6.82±0.58 mm, respectively; P<0.001). Tibia breaking strength (28.42±6.37 kg) of FG broilers was higher than those of SG broiler tibia (21.81±5.89 kg; P<0.001). Tibia density and bone mineral content (0.13±0.01 g/cm2 and 1.29±0.23 g, respectively) of FG broilers were higher than those of SG broiler tibia (0.11±0.01 g/cm2 and 0.79±0.1 g; P<0.001). Tibia percentage of ash content (39.76±2.81) of FG broilers was lower than that of SG broilers (39.99±2.67; P=0.173). Fast-growing broiler bones were longer, wider, heavier, stronger, more dense, and contained more ash than SG ones. After all parameters were calculated per unit of final BW at 6 wk, tibia density and bone ash percentage of FG broilers were lower than those of SG broilers.

Nutritional geometry of calcium and phosphorus nutrition in broiler chicks. Growth performance, skeletal health and intake arrays

“…Bone mineralisation, commonly determined from tibia ash percentage, is an accepted measure for poultry and is assumed to be highly correlated with the overall structural strength of the skeleton. Bone mineralisation, however, is only one aspect in determining bone strength; the volume of bone tissue and micro-architectural organisation also influence bone strength and skeletal health (Rath et al, 2000;Shim et al, 2012). The results of this study may support these notions, and may explain why birds with a ratio of 1.14 : 1 Ca : nPP had high tibia ash yet still exhibited signs of impaired mobility.…”

“…Bone breaking strength, bone density, mineral content and bone ash have been used as indicators of bone status and skeletal health (Shim et al, 2012). Bone mineralisation, commonly determined from tibia ash percentage, is an accepted measure for poultry and is assumed to be highly correlated with the overall structural strength of the skeleton.…”

“…The results of this study may support these notions, and may explain why birds with a ratio of 1.14 : 1 Ca : nPP had high tibia ash yet still exhibited signs of impaired mobility. Bone density may be a more accurate measure as it accounts for the mass of material per unit volume of bone in the matrix, including both organic and inorganic material and how porous the matrix is (Rath et al, 2000;Shim et al, 2012).…”

Response to withdrawal of vitamin and trace mineral premixes from finisher diet in broiler chickens under the hot and humid tropical condition

“…Withdrawal of VIT premix from 29 to 42 days of age has also been reported to affect bone parameters adversely (Moravej et al 2012a). Vitamin D, B6, C, and K are known to be essential for bone health as they are involved in the synthesis of bone matrix constituents (Weber 1999;Shim et al 2012). However, despite the importance of VIT and TRM premixes for bone strength, Skinner et al (1992) reported that withdrawal of both premixes from broiler finisher diets from 28 to 49 days had negligible effect on incidence of leg disorders.…”

Edible Giblets and Bone Mineral Characteristics of Two Slow-Growing Chicken Genotypes Reared in an Organic System

“…Bone mineral density (BMD, g/ cm 2 ) (Kim et al, 2006;Lian et al, 2004;Onyango et al, 2003;Rath et al, 2000;Shim et al, 2012;Watkins and Southern, 1992) and bone mineral content (BMC, g/cm) (Akpe et al, 1987;Almeida et al, 2008;Kim et al, 2006, Onyango et al, 2003 measurements have been used to evaluate the quality and the status of the porous structure of bone matrix. These two parameters are greatly influenced by mineral intake.…”