Morfometria testicular , escores de crista ,cloaca e de pé em galos de matriz pesada em duas idades e três categorias de peso corporal

Abstract

As in other species, in broiler breeder roosters, the weight of the testis is positively associated with daily sperm production and any changes on testis will be reflected on fertility levels. In birds, the testis are located in the celomatic cavity, not being accessible to directly reproductive evaluation as mammalian testis. The reproductive evaluation of roosters is based on phenotipyc characteristics. 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 lighter testis (T), smaller seminiferous tubule diameter (STD) and lower COS and CLS than the medium and high BW roosters (P0.05). Low BW roosters had bigger volumetric proportions of Sertoli (SC) and Leydig (LC) cells. Heavy roosters had the highest COS and bigger seminiferous epithelium height (SEH) and STD than the lighter roosters. There was no statistical difference between the BW categories in FS, gonadosomatic index (GI), in volumetric proportions of peritubular layer (PL), seminiferous epithelium (SE), lumen of the seminiferous tubule (LST), interstitial connective tissue (ICT), blood and lymphatic vessels (V) and percentage of seminiferous tubule (ST) and interstitial tissue (IT). Considering the age effect, roosters with 45 weeks of age had lower BW, GI, S, LST, LC and ST than 25-week roosters. Positive, moderate and significantly correlation was found between testis weight and phenotypic characteristics as BW, COS and CLS in 45week roosters, however these correlations were not seen in 25-week roosters. A positive, moderate and significantly correlation was found between body weight and histologic testicular characteristics as STD and SEH. In conclusion, there is a regression in the testis 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 testis weight and histological quality of the testis. COS and CLS can be used with moderate potential prediction to identify roosters with low testis weight at 45 weeks of age.