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| Author(s): |
Leila de Genova Gaya
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Pirassununga. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Zootecnica e Engenharia de Alimentos (FZE/BT) |
| Defense date: | 2006-09-01 |
| Examining board members: |
Jose Bento Sterman Ferraz;
Júlio César de Carvalho Balieiro;
Gerson Barreto Mourão;
Massami Shimokomaki;
Marco Antonio Trindade
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| Advisor: | Jose Bento Sterman Ferraz |
| Abstract | |
This research was conducted to estimate genetic and phenotypic parameters of meat quality, performance, carcass and body composition traits in a male broiler line provided by Agroceres Ross Melhoramento Genético de Aves S. A. Broilers measured belonged to a sib test program, in which data from sibs of the individuals to be selected in this line, called elite flock, are collected. Performance traits analyzed were body weight at selection (PS), body weight at slaughter (PA) and ultrasound records of pectoral muscle (US). Carcass traits analyzed were meat breast weight (PPEI), eviscerated body weight (PE) and leg weight (PPER) and the body composition traits analyzed were abdominal fat weight (GOR), liver weight (FIG) and heart weight (COR). Meat quality traits analyzed were: initial pH measure (pHi), pH measure at 6 hours after slaughter (pH6), final pH measure (pHf), initial range of pH fall (AMi), final range of pH fall (AMf), lightness (L*), redness (a*), yellowness (b*), weep losses (EXSU), drip losses (CONG), shrink losses (COZ) and shear force (FC). (Co) variance components were estimated by restricted maximum likelihood method, using the software MTDFREML. The numerator relationship matrix was composed by 107.154 individuals. For pH6, pHf and L*, moderate heritability coefficients were estimated; for the other traits these coefficients were low. Genetic correlation estimates obtained indicated a small association among meat quality traits and performance, carcass and body composition traits, except for the selection to PS, which seemed to be able to reduce water losses of meat. Genetic correlations estimates among meat quality traits could orientated the understanding of the mechanisms related to meat quality in the analyzed line; CONG, FC and L* seemed to be able to bring favorable correlationed responses, so it was recommended its use as selection criterion if existing the necessity of improving the meat quality in the analyzed line. However, this necessity was not apparent, since the genetic trends of meat quality traits were small and favorable to meat quality in the analyzed broiler line. (AU) | |