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

ABSTRACT This study was conducted to compare edible giblets weight, tibial bone mineral density (BMD), and bone mineral content (BMC) of two slow-growing broiler genotypes (Hubbard S757; S757 and Hubbard Grey Barred JA; GB-JA) reared with outdoor access, and to determine the relationship between these variables. Day-old chicks (straight-run) of the genotypes S757 (n=120) and GB-JA (n=120) were housed for 98 days. Each genotype was assigned to six pens of 20 birds each. Birds were reared in indoor floor pens and moving shelters with outdoor access (during daylight hours). Absolute body (BW), heart (HW), spleen (SW), liver (LW), gizzard (GW), and abdominal fat pad (AFW) weights of the genotype S757 and male birds were statistically higher than that of the genotype GB-JA and female birds. Genotype statistically affected relative HW, whereas sex affected relative GW. Although BMD values were not influenced by genotype or sex, S757 birds and males presented statistically higher tibial BMC, lean, lean+BMC, total mass values (g) and area (cm2) compared with GB-JA birds and females. BW, HW, SW, LW, GW and AFW were positively correlated with BMC obtained by DXA. In conclusion, the measured traits influenced by genetic strain and sex. The use of the Hubbard S757 genotype in organic production systems with outdoor access is recommend.

摘要 本研究旨在比较两种采用户外活动饲养模式的慢生长肉鸡品系——哈伯德S757（Hubbard S757，S757）与哈伯德灰羽JA（Hubbard Grey Barred JA，GB-JA）——的可食用内脏重量、胫骨骨密度（Bone Mineral Density，BMD）及骨矿含量（Bone Mineral Content，BMC），并分析上述指标间的相关性。
试验选取1日龄未分选雏鸡（straight-run），其中S757品系120只、GB-JA品系120只，饲养周期为98天。每个品系设置6个重复栏舍，每栏饲养20只鸡。试验采用室内地面栏舍搭配日间开放户外活动的移动棚舍模式进行饲养。
S757品系及公鸡的绝对体重（Body Weight，BW）、心脏重量（Heart Weight，HW）、脾脏重量（Spleen Weight，SW）、肝脏重量（Liver Weight，LW）、肌胃重量（Gizzard Weight，GW）及腹部脂肪垫重量（Abdominal Fat Pad Weight，AFW）均显著高于GB-JA品系与母鸡。品系对相对心脏重量存在显著影响，而性别则显著影响相对肌胃重量。
尽管胫骨骨密度未受品系或性别的影响，但S757品系公鸡的胫骨骨矿含量、瘦肉量、瘦肉+骨矿含量、总质量（单位：g）及面积（单位：cm²）均显著高于GB-JA品系与母鸡。通过双能X线吸收测定法（Dual-energy X-ray Absorptiometry，DXA）测得的骨矿含量与体重、心脏重量、脾脏重量、肝脏重量、肌胃重量及腹部脂肪垫重量呈显著正相关。
综上，本研究测定的指标受遗传品系与性别共同调控。建议在带有户外活动的有机养殖体系中选用哈伯德S757品系肉鸡。