The effects of broiler chicken growth rate on valgus, varus, and tibial dyschondroplasia

Abstract

An experiment was conducted to test the hypothesis that the growth rate of broilers influences their susceptibilities to bone abnormalities, causing major leg problems. Leg angulations, described in the twisted legs syndrome as valgus and bilateral or unilateral varus, were investigated in 2 subpopulations of mixed-sex Arkansas randombred broilers. Valgus angulation was classified as mild (tibia-metatarsus angle between 10 and 25°), intermediate (25-45°), or severe (> 45°). Body weight was measured at hatch and weekly until 6 wk of age. There were 8 different settings of approximately 450 eggs each. Two subpopulations, slow growing (bottom quarter, n = 581) and fast growing (top quarter, n = 585), were created from a randombred population based on their growth rate from hatch until 6 wk of age. At 6 wk of age, tibial dyschondroplasia incidences were determined by making a longitudinal cut across the right tibia. The tibial dyschondroplasia bone lesion is characterized by an abnormal white, opaque, unmineralized, and unvascularized mass of cartilage occurring in the proximal end of the tibia. It was scored from 1 (mild) to 3 (severe) depending on the cartilage plug abnormality size. Mean lesion scores of left and right valgus and tibial dyschondroplasia (0.40, 0.38, and 0.06) of fast-growing broilers were higher than those (0.26, 0.28, and 0.02) of slow-growing broilers (P = 0.0002, 0.0037, and 0.0269), respectively. Growth rate was negatively associated with the twisted legs syndrome and a bone abnormality (tibial dyschondroplasia) in this randombred population.

Protein Source and Nutrient Density in the Diets of Male Broilers from 8 to 21 Days of Age: Effects on Tibia Dimension, Breaking Strength, and Mineral Density

“…These results of the current study are, therefore, consistent with those of the previous studies. Even though bone breaking strength may not be necessarily decreased with increased BW, fast growing birds may have a higher incidence of tibial dyschondroplasia because of a larger loading weight that they must bear (Shim et al, 2012a). The current results also indicate that high energy diets may improve chicken muscle deposition without equally improving bone quality.…”

Transcriptome-based screening of intracellular pathways and angiogenesis related genes at different stages of thiram induced tibial lesions in broiler chickens

“…It can also cause membrane damage, bone morphogenic inactivation and inhibit angiogenesis [12,13]. In TD, a large number of the cartilage cell damage is due to the apoptosis process and abnormal protein secretion in the cartilage cells, causing a decrease in the cartilage extracellular matrix degradation rate, which limits the space for bone deposition [14,15]. The cells stop to multiply and endure hypertrophy and apoptosis in tibia bone.…”

WITHDRAWN: Evaluation of clinical, pathological and genetic indicators in chickens with thiram-induced tibial dyschondroplasia

“…Leach and Nesheim suggested that the TD contributes to the accumulation of cartilage extending from the epiphyseal growth plate into the metaphysis [25]. Thiram causes TD lesions [21] due to mitochondrial injury, membrane damage, inhibition of angiogenesis, and cytotoxic effects [13].…”

“…In TD, a large amount of the cartilage cell damage is due to the apoptosis process and abnormal protein secretion in cartilage cells, causing a decrease in the cartilage extracellular matrix degradation rate, which limits the space for bone deposition [12,13]. Currently, research focuses on increasing the growth rate and feed conversion ratio (FCR) of broilers; consequently, poultry bone disease incidence is also increasing in the broiler industry [5,14,15].…”