Bone Strength During Growth: Influence of Growth Rate on Cortical Porosity and Mineralization

Abstract

Although it is well accepted that bone architecture adapts to withstand the loads placed on it, the manner in which this occurs in the immature growing skeleton is not fully understood. To investigate the possible mechanisms, we have compared morphometric differences between tibiae from chickens with fast and those with slow growth potential and also distinguished between the effects of genetic potential and growth rate on their impact on bone quality. Two different fast-growing (ad lib modern) strains, one additionally feed-restricted and one slow-growing (control) strain of chicken, were compared at 15 and 42 days of age. The ad lib modern strains had similar final body weights and were approximately twice the weight of the control and restricted-fed birds. Tibiae from the control and restricted birds had a higher ash content and lower porosity than the ad lib modern strain at 42 days. The porosity was a result of rapid primary osteon formation at the periosteal surface and incomplete infilling of the resultant canal by osteoblasts. When adjusted to average body weight of contemporaries, bones from the control strain and the restricted-fed modern birds were stiffer and at least as strong as those from the fast growing ad lib-fed birds. In conclusion, rapid bone deposition at the periosteal surface was associated with decreased mineralization, increased cortical porosity, and altered biomechanical properties. Our results also indicate that growth rate, and not genetic potential, of the fast growing birds was responsible for the rapid periosteal bone deposition.

Avaliação da qualidade óssea mediante parâmetros morfométricos, bioquímicos e biomecânicos em frangos de corte

“…Já entre os sexos, machos foram maiores (P<0,05) em todas as idades, caracterizando o mesmo efeito do dimorfismo sexual encontrado por Yalçin et al (2001). O dimorfismo sexual pode estar relacionado aos níveis de hormônios, como GH, IGF-I e androstenediona em machos após 28 dias de idade, e também pode variar dentre os cruzamentos (Rose et al, 1996 Williams et al (2004) sugeriram que, à medida que o animal cresce, a forma geométrica do osso se torna menos circular, podendo não deixar transparecer possíveis diferenças quanto à área da seção transversal e o momento da inércia. Muitas variáveis ósseas não são afetadas pela origem genética, mas existe forte correlação entre o PV e o volume do osso e a área da seção transversal, independentemente da origem genética (Leterrier et al, 1998).…”

“…Isso sugere que a qualidade dos ossos de Hb3 foi comprometida, já que esse híbrido apresentou maior peso vivo. Este comprometimento do material ósseo pode estar relacionado à alta taxa de síntese e absorção nos ossos em desenvolvimento de animais de crescimento rápido para o ajuste do seu tamanho e de sua geometria ao maior peso imposto (Williams et al, 2004). Isso explica, em parte, o aparecimento de deformidades ósseas em animais mais pesados em mesma idade e com mesmas propriedades biomecânicas (Leterrier & Nys, 1992).…”

Productive performances and carcase quality of male and female Italian Padovana and Polverara slow-growing chicken breeds

“…Then, mature bones can reach their optimum physical and biomechanical properties because they have the time to complete their structural development and the mineralisation processes (Rath et al 2000). The impressive growth rate and final live weight of heavy strains predispose broiler chickens to bone weakness, deformities, lameness (Julian 1998;Williams et al 2004;Salaam et al 2016) and to cortical bone fractures during catching and transportation (Rath et al 2000); these problems are scarce or absent in slower growing strains (Havenstein et al 1994). On the one hand, these skeletal abnormalities represent a welfare issue, because they are painful and reduce walking ability (Bradshaw et al 2002); as a consequence, lame broilers have more breast blisters, scratches, inflammatory processes and muscle atrophy (Julian 1998;Vaillancourt and Martinez 2002) as they spend more time lying in the litter (Oviedo-Rond on et al 2009).…”

The effect of <i>Moringa oleifera</i> leaf meal supplementation on tibia strength, morphology and inorganic content of broiler chickens

“…Moreover, traditionally, estimates of P needs for growing broilers have been estimated primarily on tibia ash values (NRC, 1994). In modern meat-type chickens, bone strength and development are closely linked to the expression of genetic potential for maximum lean muscle deposition (Williams et al, 2004). Thus, the increase in dry bone weight and mineral content per unit bone length responds to mechanical forces placed on the bone (McDevitt et al, 2006;Whitehead, 2007;Talaty et al, 2009a).…”