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| Author(s): |
Aline Mondini Calil Racanicci
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2004-09-03 |
| Examining board members: |
Jose Fernando Machado Menten;
Marisa Aparecida Bismara Regitano D Arce;
Douglas Emygdio de Faria;
Massami Shimokomaki;
Elizabeth Aparecida Ferraz da Silva Torres
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| Advisor: | Jose Fernando Machado Menten; Marisa Aparecida Bismara Regitano D Arce |
| Abstract | |
Fats and oils are widely used in poultry diets to increase energy density and improve broiler performance. However, some fats and oils are highly sensitive to oxidation during storage and the intake of oxidized feed may lead to poor peformance and decreased oxidative stability of poultry meat. Two experiments were conducted feeding broiler chickens with fresh or oxidized poultry offal fat to measure its effects on performance and meat stability. Fresh poultry fat was supplied by a local rendering and kept fresh by freezing (-18 oC). The oxidized poultry fat was obtained by heating at high temperatures. In the first experiment, a metabolism assay was conducted using 48 AgRoss male broilers, from 31 to 34 days of age. Birds were fed a corn-soy diet or this diet with 10% of fresh or oxidized fat. The results of apparent metabolizable energy (AME) and N-corrected apparent metabolizable energy (AMEn) were 9,240 and 9,150 kcal/kg (as fed-basis) when fed as fresh poultry fat and 7,770 and 7,595 kcal/kg when fed as oxidized poultry fat. These data indicate a 17% reduction on AME and AMEn values (P<0.0001) for the oxidized fat, probably due to the negative effects of lipid oxidation. The second and the third experiments were conducted to evaluate broiler performance and oxidative stability of thigh meat stored chilled and frozen. Birds (160 male Cobb chicks in the second experiment and 200 male AgRoss chicks in the third experiment) were fed a corn-soy diet containing 4% of fresh or oxidized poultry fat from 10 days to slaughter. Intake of oxidized poultry fat had no effect on bird performance and on carcass characteristics. There were no differences on meat pH and color (L*, a* and b* values) between dietary treatments during chilled and frozen storage. The inclusion of oxidized poultry fat in the birds diets depressed oxidative stability of thigh muscle during chilled and frozen storage. For the oxidized treatment, TBARS values were statistically higher (P=0.0016) at the end of 12 days of chilled storage, and were also higher (P<0.10) after six months of frozen storage. (AU) | |