Comb, cloaca and feet scores and testis morphometry in male broiler breeders at two different ages

Abstract

In broiler breeder roosters, the weight of the testes is positively associated with daily sperm production and fertility. In birds, the testes are located in the coelomic cavity, not being accessible to reproductive evaluation as mammalian testes. The reproductive evaluation of roosters is based on phenotypic traits. Any changes on testes will be reflected on fertility levels. The aim of this paper was to evaluate the potential of association of phenotypic traits as body weight (BW), comb scores (COS), cloaca scores (CLS) and feet scores (FS) with testicular morphometric parameters in adult Cobb® Mx roosters in two ages (25 and 45 weeks of age). The low BW roosters had lower testes weight (TW), smaller seminiferous tubule diameter (STD) and lower comb and cloaca scores than the medium and high BW roosters (P≤0.05). Heavy roosters had the highest COS and bigger seminiferous epithelium height (SEH). There was no statistical difference between the BW categories in FS and volumetric proportion of seminiferous tubule (ST) and interstitial tissue (IT). Considering the age effect, roosters with 45 weeks of age had lower TW and ST than 25-week roosters. Positive, moderate and significant correlation was found between testes weight and phenotypic characteristics as BW, COS and CLS in 45week roosters. A positive, moderate and significant correlation was found between body weight and histologic testicular characteristics as STD and SHE in both evaluated ages. In conclusion, there is a regression in the testes weight with age and it is more intense in Cobb® Mx roosters with lower BW. Furthermore, it is concluded that the BW positively influences the testes weight and histological quality of the testes. COS and CLS can be used with moderate potential prediction to identify roosters with low testes weight at 45 weeks of age.Keywords: testicular regression, rooster, histomorphometry, phenotypic characteristics, histology RESUMO Em galos de matriz pesada sabe-se que o peso dos testículos pode ser associado positivamente com a produção diária de espermatozoides e que alterações nos testículos irão refletir na fertilidade. Nas aves, os testículos estão localizados dentro da cavidade celomática, e, portanto, não são acessíveis para exame andrológico direto, como em mamíferos. A avaliação reprodutiva de galos se baseia principalmente em características fenotípicas. Buscou-se avaliar o potencial de associação de alguns parâmetros fenotípicos, como peso corporal (PC), escores de crista (ECR), escores de cloaca (ECL) e escores de pés (EP), com parâmetros morfológicos de testículos em galos Cobb® Mx em duas idades (25 e 45 semanas de idade). Galos leves apresentaram menor peso testicular (PT), menor diâmetro de túbulo seminífero (DT), e menores ECR e ECL que galos médios e pesados (P≤0.05). Galos pesados apresentaram os maiores ECR e maiores valores

Relationships Between Morphological Characteristics of Roosters in Broiler Breeders at Different Age Periods

“…It was to be expected thus body weight is a trait affected by age (Hocking and Bernard, 1997). The results are in accordance with the Leão et al (2017) who showed that body weight increased with age (25 to 45 weeks of age) in male broiler breeders. Meanwhile, Özdemir (2019) reported that an increase in bodyweight with age in both İspenç genotype roosters and chickens.…”

“…Kumar et al (2022) in a study carried on Aseel and Kadaknath chickens at 24 week of age reported a correlation between body weight and comb length. Almost similar study was carried by Leão et al (2017) that showed positive significant correlation between histological comb score and live weight. Also, Rizzi and Verdiglione (2015) reported that there was a correlation between comb and wattles weight and body weight in Italian purebreds of Robusta lionata.…”

“…But the other comb characteristics such as, comb width and comb area were found similar in investigated age periods. However, Leão et al (2017) revealed that there was no difference for histological comb score between the 25 and 45 WOA groups.…”

Effect of Carbohydrate Type and Phenotype on the Quality of Post-Thawing Frozen Semen of KUB Chicken

“…Comb growth is closely related to testosterone and aggressiveness in poultry (Mukhtar & Khan2012). The stimulation of intracellular fluid generation by fibroblasts in the comb and dewlap by testosterone and dihydrotestosterone is known to affect the growth of these tissues (Leão et al 2017). The comb is located on the head and functions for thermoregulation (Iyasere et al 2021), so a large comb provides better temperature regulation than smaller combs.…”