Effects of strain, maternal age and sex on morphological characteristics and composition of tibial bone in broilers

Abstract

1. This study was to determine the effects of strain, age of the maternal flock and sex on morphological characteristics and composition of tibial bone of broilers from hatch to 48 d of age. 2. A total of 600 chicks was obtained from 2 strains of broiler breeder flocks (150/chicks/strain/maternal age). Maternal flock age was classified as young (32 to 35 weeks of age) or old (56 to 58 weeks of age). Birds were reared under standard feeding and lighting regimes. 3. On day 1, 16, 32 and 48, twelve birds were selected at random from each maternal group, strain and sex and killed. The wet bone weight and volume were measured. Morphological characteristics of tibia were determined using radiography. Bone breaking strength was tested. Tibia dry matter, ash content, mineral density and collagen level were determined. 4. A quadratic increase occurred with increase in age of broilers for all variables, except proximal width, medial cortex thickness and distal condyle width which increased in a linear manner. 5. Maternal age had a significant effect only on the variably measured at the time of hatch. On day of hatch bone weight, ash content and bone volume were affected by maternal age, but the extent of this also depended on the strain. 6. The differences observed between strains for bone anatomy and bone mineralisation during the rapid growth period of 16 d were not significant at later ages, with the exception of bone volume. Differences between sexes were evident from 16 to 49 d of age with females having lower values.

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

“…With the increased prevalence of leg disorders and the difference in muscle distribution, considerable attention has been given to the morphological and composition of the leg bones of broilers (Yalcin et al, 2001). 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).…”

Breeder age and bone development in broiler chicken embryos

“…This finding is of practical interest since the wider bone of broilers from older breeders can increase the resistance to break. Even though, according to Yalçin et al (2001), the effect of breeder age on bone morphometry is not present in later phases during broiler rearing, thus the findings of the present study warrant further investigations.…”

“…These measurements were greater in embryos from 60-week-old breeders compared to 38-week-old breeders. The greater bone weight in embryos from older breeders might result from a greater mineral density, such as that observed by Yalçin et al (2001) in newly hatched chicks. However, as previously discussed, the mineralization activity in long bones was not different due to breeder age, and when weight was expressed as a percentage of embryo weight (relative weight), the breeder age effect disappeared.…”

“…The other variables had quadratic effects as a function of incubation day. Yalçin et al (2001) suggested that bone weight followed the overall embryo development. It is known that older breeders lay heavier eggs, consequently, chick weight also increases (Pinchasov, 1991;Vieira and Moran, 1998 a, b;Tona et al, 2004).…”

“…As previously explained, this increase might be attributed to a wider hypertrophic zone of the growth plate. According to Yalçin et al (2001), such linear increase in the width of tibial epiphyses in embryos continues after hatching and lasts until market-age in broilers.…”