Phenotypic Analysis of Growth and Morphological Traits in Miniature Breeds of Japanese Indigenous Chickens

Abstract

Japanese indigenous chickens include approximately 50 breeds exhibiting various morphological traits, such as a long tail. These genetic resources will be important for revealing the genetic basis of morphological traits in the future. However, little is known about the phenotypic characteristics of each breed during the growth stages. To understand age-dependent changes in growth and morphological traits, we investigated tail length, tail number, body weight, and shank length at several time points using three genetically distinct Japanese indigenous chicken breeds. A total of 155 birds from the Tosa-jidori, Chabo, and Minohikichabo breeds were used for trait measurements from 1 to 36 weeks of age to reveal breed and sex effects. Significant sex differences through the growth stages were observed for all traits except for tail number. Although there were no clear breed differences in tail length traits at the 6- and 20-week stages, Minohikichabo ultimately had a significantly longer tail due to extended tail feather growth at later stages (28 and 36 weeks). By measuring two tail length variables (central and maximum), it was revealed that the shape of the tail feathers varies with the growth stage. Minohikichabo's tail number was higher than that of Tosajidori and Chabo at earlier ages (8 and 16 weeks), which leads to an elegant visual in Minohikichabo. Tosa-jidori's body weight was higher than that of Chabo and Minohikichabo, whereas the shank lengths of Chabo and Minohikichabo were shorter than those of Tosa-jidori. These differences in body weight and shank length were consistent from the early to late growth stages. These results revealed the age-dependency of growth and morphological trait breed characteristics.

Genetic effect on free amino acid contents of egg yolk and albumen using five different chicken genotypes under floor rearing system

“…For example, the Japanese indigenous chicken breeds of "Onagadori" has extremely long tail feathers in male [3,4], while the weight of male "Oh-Shamo" reaches 4-6 kg [3,5,6]. Thus, the indigenous chickens have a large potential for studying genetic and phenotypic diversity [7].…”

Blood transcriptome comparison between sexes and their function in 4-week Rhode Island red chickens

“…Besides, the growth stages of chickens are generally constituted with early growth stage (4–16-weeks), late growth stage (by 24-weeks), and mature growth stage (after 24-weeks), which can be a factor in phenotype, physiological parameters, and genes expression with sexes. These are reported to be effective before the mature growth stage (Podisi et al 2013 ; Li et al 2017 ; Xue et al 2017 ; Ono et al 2022 ). Especially, the early growth stage is expressed various gens related growth for lipid metabolism and hormone regulation in adipose and muscle tissues, and sexes are led to factors affecting differentially expressed genes at this point (Dridi et al 2007 ; Abdullah et al 2010 ; Ons et al 2010 ; Yu-Jiang et al 2020 ).…”

Morphological variations of caudal skeleton between three chicken breeds

“…We previously detailed the morphological traits of Japanese Old Type-Tosa (Tosa-jidori), Japanese Bantam (Chabo), and Japanese Tail Dragger (Minohikichabo) small breeds that have different characteristic caudae [ 4 ]. Tosa-jidori is one of the oldest ornamental breeds in Japan, the smallest among Japanese native chickens, and they have curved tail feathers [ 6 ].…”

“…The word “chabo” in “Minohikichabo” means small chickens in Japan, not the Japanese Bantam companion. The length of the tail feathers is similar among these breeds at the young chick (age, <24 weeks) stage, whereas the tail feathers become significantly longer in Minohikichabo than in Tosa-jidori and Chabo chickens after 28 weeks of age [ 4 ]. In addition, Minohikichabo have far more tail feathers between the uropygial gland and the cloaca than the other two breeds [ 4 ].…”

“…The length of the tail feathers is similar among these breeds at the young chick (age, <24 weeks) stage, whereas the tail feathers become significantly longer in Minohikichabo than in Tosa-jidori and Chabo chickens after 28 weeks of age [ 4 ]. In addition, Minohikichabo have far more tail feathers between the uropygial gland and the cloaca than the other two breeds [ 4 ]. These findings provided a morphological basis for differences between wild-type and rich, but not erect caudae.…”