RESUMO
The objective of this study was to describe the growth curve of Brazilian Creole chickens of the Canela-Preta breed raised in two different rearing systems using non-linear growth models. A total of 400 birds were divided into two groups of 200 animals (of both genders), which were kept in confined or semi-confined systems. The confined birds were housed in an experimental masonry shed and the semi-confined animals were housed in another shed with access to pasture from 29 days of age. Birds were individually weighed every seven days during six months for determination of the growth curves of body weight using 10 non-linear models. The parameters of the models were estimated using the Gauss Newton method. The performance of the models was assessed using mean squared error (MSE), coefficient of determination (R2), percentage of convergence, and residual mean absolute deviation (MAD). With the exception of the Inverse Polynomial, all the other models had R2 values close to one. Therefore, the best models were chosen based on the lowest MSE and MAD values, with the Richards model ranking first followed by the Von Bertalanffy model. Gender and rearing system effects significantly influenced (p<0.05) some parameters of the Richards model. In conclusion, the Richards model was the most adequate to describe the growth of Canela-Preta chickens. Gender and rearing system significantly influenced the growth of the birds. The growth rates observed indicated that management strategies can be performed to increase the production efficiency of Canela-Preta chickens.(AU)
Assuntos
Animais , Peso Corporal/fisiologia , Galinhas/crescimento & desenvolvimento , Dinâmica não LinearRESUMO
O objetivo deste trabalho consistiu na aplicação de indicadores socioambientais em pisciculturas familiares localizadas na região do Vale do Ribeira, em área de Mata Atlântica, no sudoeste do estado de São Paulo. Para isso, foram identificadas 84 propriedades. Dessas, 40 foram selecionadas como unidades amostrais. Entre as principais características identificadas, 32% possuem lâmina d'água inferior a cinco hectares, com viveiros escavados em sistema semi-intensivo, 58% utilizam mão de obra familiar e 23% apontam a ausência de assistência técnica especializada como o principal problema enfrentado. A tilápia-do-nilo (Oreochromis niloticus) representa 57% das espécies produzidas em sistemas de monocultivo ou policultivo. Contudo, as pisciculturas familiares são classificadas como sistemas produtivos de pequeno porte, com destaque para a necessidade de adequação de recursos naturais, da capacidade de gestão e da eficiência das práticas de produção. Os indicadores sociais variaram de 0,75 a 1,00 para equidade salarial, proporção de autoemprego, uso de mão de obra local, inclusão de gênero e inclusão etária, demonstrando a capacidade que a aquicultura tem para auxiliar no desenvolvimento social local, por meio da geração de emprego e renda.(AU)
The objective of this work was to apply socioenvironmental indicators in family fish farms located in the Ribeira Valley region, Atlantic Forest area, southwest of São Paulo state, Brazil. Thus, we identified 84 production units. Of these, we selected 40 as sample units. Among the main characteristics identified, 32% have water depth of less than five hectares with excavated ponds in semi-intensive system, 58% use family labor and 23% report the lack of specialized technical assistance as the main problem faced. The Nile tilapia (Oreochromis niloticus) represents 57% of the species produced in monoculture or polyculture systems. Therefore, family fish farms are classified as small production systems with emphasis on the need to adapt natural resources, management capacity and efficiency of production practices. Social indicators ranged from 0.75 to 1.00 for salary equity, proportion of self-employment, use of local labor, gender inclusion and age inclusion, demonstrating the ability of aquaculture to assist local social development through job and income generation.(AU)