Meat Quality of Slow- and Fast-Growing Chicken Genotypes Fed Low-Nutrient or Standard Diets and Raised Indoors or with Outdoor Access

Abstract

Consumer interest in free-range and organic poultry is growing. Two concurrent experiments were conducted to assess 1) the impact of alternative genotype and production system and 2) the impact of genotype and diet on meat quality of chickens for specialty markets. Specifically, a slow-growing genotype (slow) and a fast-growing genotype (fast) were raised for 91 and 63 d (females), respectively, or 84 and 56 d in the case of the second trial (males). In each trial, the slow birds were placed before the fast birds to achieve a similar final BW at processing. Each genotype was assigned to 4 pens of 20 birds each and raised in indoor floor pens in a conventional poultry research facility; each genotype was also assigned to 4 floor pens in a small facility with outdoor access. A low-nutrient diet was used, formulated for a slower rate of production. Birds were commercially processed and deboned at 4 h postmortem. In the second trial, the diets compared were a conventional diet that met NRC requirements or the low-nutrient diet, and all birds were raised indoors. There was an interaction between genotype and production system for the color (b*; P < 0.05). The meat and skin of the slow birds became more yellow when the birds had outdoor access; however, this did not occur when the fast birds had outdoor access. The breast meat of the slow birds had more protein and alpha-tocopherol (P < 0.05) than the fast birds and half the amount of fat (P < 0.05). In addition, the meat of the outdoor birds had more protein than the indoor birds (P < 0.05). The slow birds had poorer water-holding capacity but were more tender than the fast birds (P < 0.05). The type of diet had little impact on meat quality. These data indicate that meat quality differences exist between genotypes with different growth rates and raised in alternative production systems.

Effects of strain and sex on the behaviour of free-range slow-growing chickens raised in a hot environment

“…These behaviours help to remove stale oil from feathers and are particularly important in free-range chickens which are often exposed to various edaphic and biotic factors, hence parasite infestation. The maximum environmental temperature recorded in the current study was much higher than 18-24°C, which is the TNZ for chickens (Fanatico et al 2007). At ambient temperatures within the TNZ, chickens are able to maintain their body temperature.…”

“…This impairs normal body functions as efficiency is achieved if body temperature is kept constant or maintained within a narrow range (Ayo et al 2011). The normal body temperature of an adult chicken is 40.6-41.7°C, while the thermo-neutral zone (TNZ) is 18-24°C (Fanatico et al 2007). …”

Linhagens de frangos caipiras criadas em sistema semi-intensivo em região de clima quente

“…O bem-estar na produção de aves está diretamente relacionado com o sistema de criação (Moura et al, 2010;Fraser et al, 2013). O sistema de semiconfinamento permite que as aves tenham livre acesso às áreas de pastejo, para que estas expressem seus comportamentos naturais, resultando em diferenças particulares na qualidade da carne, quando comparadas com as aves criadas confinadas (Fanatico et al, 2007;Mikulski et al, 2011). Por outro lado, as condições ambientais podem interferir no bem-estar, saúde e comportamento das aves, podendo se refletir em suas características fisiológicas e produtivas (Fouad et al, 2008;Tan et al, 2010).…”

Do rearing system and free-range stocking density affect meat quality of chickens fed feed mixture with rapeseed oil?

“…The basic breast chemical composition (Table 5) was not significantly affected by the rearing system except dry matter. In the literature, Fanatico et al (2007) and Skrivan et al (2015) did not observe any effect of the rearing system on the meat chemical composition. The indoor chickens had significantly (P = 0.003) higher dry matter compared with both free-range groups.…”