Histomorphometry and Vitamin D Metabolism of Valgus-Varus Deformity in Broiler Chickens

Jw, Newbrey; Sn, Baksi; As, Dhillon; Ng, Zimmerman; Sg, Truitt; Riedinger, R

doi:10.2307/1590988

Cited by 24 publications

(14 citation statements)

References 14 publications

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“…Diaphyseal crosssections were also analysed with the Visilog software in order to quantify cortical and marrow areas and diameters. The cortex was divided into a peripheral active zone, a mature zone and a resorption zone [14,17].…”

Section: Methodsmentioning

confidence: 99%

Bone development and activity in chickens in response to reduced weight-load on legs

Rutten

Leterrier²,

Constantin³

et al. 2002

Anim. Res.

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-In order to find out whether a reduction in load-bearing on chicken legs would modify the activity and leg bone tissue, an original suspension device was developed in order to alleviate half of the weight-load on the legs. Thirty-six 5 d-old male meat-type chicks were assigned to 12 groups, each of 3 birds: a control bird (C), a bird equipped with a harness (H) and one equipped with a harness and suspended from a balance (S). The counterweights of the balance reduced the load on the legs by 50%. Behaviour in the birds was recorded twice for a 22-hour period. The birds were slaughtered at 19 d of age. Their legs were then weighed and the humeri, tibiotarsi and femurs were used for computation of length, biomechanical stiffness and composition. Tibiotarsi were also used for histomorphometry. Body weight at 19 d of age was significantly higher in the C birds (642 g vs. 586 g in the H and S groups, P < 0.05). The distance travelled as measured in the second week of the experiment was greater in S birds (338 m per 22 h vs. 246 in the C group and 252 in the H group, P < 0.05). The length of the tibiotarsi and femora was greater in the S birds when corrected for body weight (P < 0.05). Bone stiffness, composition and histological parameters were not significantly different in the 3 groups. We thus concluded that a reduction in load-bearing on the legs of young chicks enhances locomotor activity and longitudinal growth of leg bones. Bone quality was not affected, probably due to the contradictory effects of increased exercise and reduced weight.

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Section: Methodsmentioning

confidence: 99%

Bone development and activity in chickens in response to reduced weight-load on legs

Rutten

Leterrier²,

Constantin³

et al. 2002

Anim. Res.

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“…The porosity (area of lacunae/cortical area, %) was measured in 4 quadrants of cortical bone: anterior, lateral, medial and posterior. A second evaluation of porosity was obtained by measuring the thickness of active, dense and endosteal zones in the cortex of each quadrant (Newbrey et al, 1988). Mineral apposition rate (MAR, m m/day;Par tt et al, 1987) was evaluated in 5 osteones from each previously described quadrant.…”

Section: Histologymentioning

confidence: 99%

“…Comparisons between healthy and lame birds show modi cations of bone cortex: hypertrophy of the diaphysial cortex (Itakura and Yamagiwa, 1970;Cruickshank and Sim, 1986), altered con gurations of tibial cross-sections (Newbrey et al, 1988) and even reduced ash content (Leterrier and Nys, 1992a). However there is no evidence that these changes were present at the initial stage of the disease.…”

Section: Introductionmentioning

confidence: 99%

Reducing growth rate of broiler chickens with a low energy diet does not improve cortical bone quality

Leterrier¹,

Rose²,

Constantin³

et al. 1998

British Poultry Science

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1. Reducing growth rate is often supposed to allow better skeletal development and improve bone quality. In order to test this assumption, flocks of broiler chickens fed on a diet containing 13.31 MJ ME/kg (H) were compared with flocks in which the growth rate was reduced by feeding birds with a low energy diet (L, 9.62 MJ ME/kg). 2. Bone growth was studied in 2 experiments in order to identify any changes in bone tissue of slow-growing chickens that might explain why they are less predisposed to varus-valgus deformities (3.1% vs 19.9%). 3. In experiment 1, the morphology, composition and histomorphometry of the tibiotarsi were analysed in both groups at 1, 12, 26, 42 and 46 d of age. Tibial variables (weight, volume, length, cortex size and structure, dry content and ash percentage) were always reduced in slow-growing birds except at 42 d of age, when tibial weight and cortex areas were similar in both groups. 4. Every variable was similar in both groups, or even higher in H birds, when chickens were compared at similar body weight, suggesting that the low growth rate did not improve bone quantity or quality of the tibiae. 5. In experiment 2, the composition of the tibiotarsi was compared every 2 days during the first week and twice a week until 36 d of age, in H and L birds. Weight and composition of the tibiotarsi did not differ between groups when compared at equal body weight, as also shown in experiment 1. 6. The reduced occurrence of varus-valgus deformities in slow-growing chicks cannot be related to an improvement in the structure and the composition of their bone tissue.

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“…Two principal forms of skeletal abnormalities that have been defined as areas of concern (Riddell, 1981) are defective bone formation or osteodystrophy and abnormal cartilage formation, such as that seen in dyschondroplasia. The incidences of bone deformity attributed to abnormal cartilage formation, in the form of tibial dyschondroplasia, and osteodystrophy are considered to be, respectively, 1 to 3% and 5% (Riddell et al, 1971;Poulos et al, 1978;Newbrey et al, 1988). However, these definitions can become blurred as tibial dyschondroplasia can be linked to defective bone formation (Lynch et al, 1991).…”

Section: Young Rapidly Growing Broiler Chicksmentioning

confidence: 99%

“…Some studies indicate that broilers with bone deformities have delayed cortical bone formation (Newbrey et ah, 1988), poor metaphyseal modelling (Dammrich & Rodenhoff, 1970;Itakura & Yamagiwa, 1970, 1971 and decreased plasma 1,25 dihydroxycholecalciferol levels (Newbrey et al, 1988), suggesting that in some birds with deformities there is an overall reduction in bone formation and turnover. As prostaglandins are local mediators of skeletal remodelling it has been suggested that deficient prostaglandin metabolism, induced by nutrition or activity, could be a cause of bone deformities (Newbrey et al, 1988). However, lower metabolic activity in disabilitated birds with severe deformities appears the more likely cause of reduced bone formation and turnover.…”

Section: Torsional (Rotational) and Valgus/varus (Angular) Deformitymentioning

confidence: 99%

Skeletal disorders in the fowl: A review

Thorp

1994

Avian Pathology

128

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SUMMARYSelection pressure for production traits in modern lines of poultry has placed increasing demands on skeletal integrity. Disruption of the normal process of skeletal growth and homeostasis results in bone diseases that are manifest throughout the modern poultry industry. Bone conditions in poultry can be grouped under three headings based on the age and type of fowls affected, and are indicative of the genetic and production stresses applied to the skeleton. In broilers during growth it is primarily pathologies of the growth plate that lead to most skeletal disorders. In broiler and turkey breeding stock the progressive degeneration of the articular cartilage results in osteoarthrosis, lameness and a consequential loss of reproductive performance. In laying hens bone fragility is most frequently the result of osteoporosis. Before attempting to determine the aetiology of a skeletal disorder an accurate diagnosis must be made. Only then can short-and long-term strategies be developed for the prevention and control of skeletal disorders. Diagnosis requires gross and histological examination, and also dietary, environmental and management analyses. The pathology often reflects lesions initiated when the bird was considerably younger and analyses must extend to assessing the factors prevalent during the initiation of lesions. Current studies are furthering the understanding of the aetiopathogenesis of avian skeletal disorders. For example, structural bone loss at the onset of follicular activity before egg-laying is pivotal to the development of osteoporosis in layers and deficiencies in growth factor expression are integral to the development of tibial dyschondroplasia.

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Histomorphometry and Vitamin D Metabolism of Valgus-Varus Deformity in Broiler Chickens

Cited by 24 publications

References 14 publications

Bone development and activity in chickens in response to reduced weight-load on legs

Bone development and activity in chickens in response to reduced weight-load on legs

Reducing growth rate of broiler chickens with a low energy diet does not improve cortical bone quality

Skeletal disorders in the fowl: A review

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