Descrição do Crescimento do Corpo e Principais Componentes de Aves de Postura
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2018-02-22
Autores
Alves, Warley Junior
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Universidade Estadual Paulista (Unesp)
Resumo
A eficácia de um programa nutricional depende do conhecimento a respeito do potencial genético de crescimento da ave, por ser esta a forma racional de calcular as exigências nutricionais e predizer o consumo de alimento. Neste sentido, os modelos fatoriais integrados as curvas de crescimento de aves auxilia no estabelecimento ou avaliação de programas alimentares específicos. Por serem modelos dinâmicos, possibilitam calcular a ingestão de acordo com o padrão de crescimento da linhagem ao longo do tempo. Tradicionalmente, a avaliação da composição corporal é feita por abate comparativo que impossibilita o acesso rápido às informações e inviabiliza o estudo das variações das caraterísticas estudadas no decorrer do tempo no mesmo animal. Uma alternativa é a técnica de absorciometria por duplo feixe de raios-X (DXA) que permite avaliar in vivo a composição corporal das aves em tempo real sem a necessidade de sacrifica-la, conciliando interesses sociais e científicos. Com base nisso, objetivou-se neste trabalho descrever o potencial de crescimento do corpo e componentes corporais de poedeiras Dekalb e Lohmann (White e Brown) meio da função Gompertz, com a composição corporal tomado pela técnica DXA nas mesmas aves no decorrer do crescimento. Foram utilizadas 360 poedeiras das linhagens Lohmann e Dekalb distribuídas em delineamento inteiramente ao acaso, com quatro tratamentos (linhagens) e seis repetições com 15 aves. As aves foram alojadas em galpão experimental dotado de gaiolas em sistema piramidal, controle de temperatura automatizado, comedouro tipo calha e bebedouro nipple. O programa alimentar adotado foi ad libitum composto por cinco dietas segundo a idade formuladas de forma a atender as exigências nutricionais das linhagens, garantindo que não houvesse nenhum nutriente limitante. Para descrição do crescimento uma ave por unidade experimental foi tomada aleatoriamente, identificada, e avaliadas do 1º ao 126º dia de idade, nas idades 1, 14, 28, 56, 70, 77, 84, 98, 112 e 126 dias, foram escaneadas para estimar o conteúdo mineral ósseo, tecido magro e gordo, por meio da absorciometria por duplo feixe de Raios X (DXA), usando modelo Hologic-QDR®. Concomitantemente, fez-se um estudo para relacionar dados de composição obtidos pelo DXA e por análise química do corpo livre de penas (CLP), Esses dados foram submetidos à análise de variância (ANOVA), sendo constatadas diferenças na quantificação da composição corporal pelas diferentes técnicas. Devido à essas diferenças, foram ajustadas regressões para cada componente químico do corpo, assim foram gerados equações de correção dos dados obtidos pelo DXA em referencia ao método químico, usando para isso aves Dekalb Brown, seguindo as mesmas idades e procedimentos do estudo de crescimento. A função Gompertz foi utilizada para descrever o crescimento do corpo e componentes químicos para cada linhagem. A mensuração da composição corporal nas mesmas aves ao longo do tempo pelo DXA auxiliou na redução do erro na avaliação do crescimento de poedeiras. As linhagens avaliadas neste estudo apresentaram diferenças no crescimento do corpo, penas e componentes entre se. E os parâmetros de crescimento aqui descritos condizem com os encontrados na literatura, e auxiliará no aperfeiçoamento de modelos de calculo de exigências nutricionais, melhorando a eficácia de programas alimentares.
The efficacy of a nutritional program depends on knowledge about the bird's genetic potential for growth, since this is the rational way of calculating nutritional requirements and predicting food consumption. In this sense, the factorial models integrated the growth curves of birds assists in the establishment or evaluation of specific food programs. Because they are dynamic models, they make it possible to calculate the feed intake according to the growth pattern of the lineage over time. Traditionally the evaluation of the body composition is made by comparative slaughter, impossibility the quick access to the information and to study the variations of the characteristics studied in the course of time in the same animal. An alternative is the X-ray absorptiometry technique (DXA) that allows in vivo evaluation of the body composition of the birds without the need to sacrifice them reconciling social and scientific interests. Based on this, the objective of this work was to describe the growth potential of the body and body components of laying hens Dekalb and Lohmann (White and Brown) through of the Gompertz function, with the body composition taken by the DXA technique in the same birds during the growth. A total of 360 laying hens of the Lohmann and Dekalb strains were used in a completely randomized design, with four treatments (strains) and six replicates of 15 birds. The birds were housed in experimental shed with cages in pyramidal system and with automated temperature control. Diets were provides ad libitum and composed of five diets according to age formulated to meet the nutritional requirements of the strains, ensuring that there was no limiting nutrient. To describe the growth, one bird per experimental unit was randomly identified and evaluated from 1 to 126 days of age. In the ages 0, 14, 28, 56, 70, 77, 84, 98, 112 and 126 days, birds were scanned to estimate bone mineral content, lean and fat tissue by means of dual beam X-ray absorptiometry (DXA) using Hologic-QDR® model. At the same time, a study was performed to correlate composition data obtained by DXA and by chemical analysis of the feather free body (FFB). These data were submitted to analysis of variance (ANOVA), being verified differences in the quantification of the body composition by the different techniques. Due to these differences, regressions were adjusted for each chemical component of the body, thus generating correction equations of the data obtained by DXA in reference to the chemical method, using Dekalb Brown birds, following the same ages and procedures of the growth study. The Gompertz function was used to describe the growth of the body and chemical components for each strain. The measurement of body composition in the same birds over time by DXA assisted in the reduction of error in the evaluation of the growth of laying hens. The strains evaluated in this study showed differences in body growth, feathers and components among themselves. And the growth parameters described here are consistent with those found in the literature, and will aid in the improvement of models for calculating nutritional requirements, improving the effectiveness of feeding programs.
The efficacy of a nutritional program depends on knowledge about the bird's genetic potential for growth, since this is the rational way of calculating nutritional requirements and predicting food consumption. In this sense, the factorial models integrated the growth curves of birds assists in the establishment or evaluation of specific food programs. Because they are dynamic models, they make it possible to calculate the feed intake according to the growth pattern of the lineage over time. Traditionally the evaluation of the body composition is made by comparative slaughter, impossibility the quick access to the information and to study the variations of the characteristics studied in the course of time in the same animal. An alternative is the X-ray absorptiometry technique (DXA) that allows in vivo evaluation of the body composition of the birds without the need to sacrifice them reconciling social and scientific interests. Based on this, the objective of this work was to describe the growth potential of the body and body components of laying hens Dekalb and Lohmann (White and Brown) through of the Gompertz function, with the body composition taken by the DXA technique in the same birds during the growth. A total of 360 laying hens of the Lohmann and Dekalb strains were used in a completely randomized design, with four treatments (strains) and six replicates of 15 birds. The birds were housed in experimental shed with cages in pyramidal system and with automated temperature control. Diets were provides ad libitum and composed of five diets according to age formulated to meet the nutritional requirements of the strains, ensuring that there was no limiting nutrient. To describe the growth, one bird per experimental unit was randomly identified and evaluated from 1 to 126 days of age. In the ages 0, 14, 28, 56, 70, 77, 84, 98, 112 and 126 days, birds were scanned to estimate bone mineral content, lean and fat tissue by means of dual beam X-ray absorptiometry (DXA) using Hologic-QDR® model. At the same time, a study was performed to correlate composition data obtained by DXA and by chemical analysis of the feather free body (FFB). These data were submitted to analysis of variance (ANOVA), being verified differences in the quantification of the body composition by the different techniques. Due to these differences, regressions were adjusted for each chemical component of the body, thus generating correction equations of the data obtained by DXA in reference to the chemical method, using Dekalb Brown birds, following the same ages and procedures of the growth study. The Gompertz function was used to describe the growth of the body and chemical components for each strain. The measurement of body composition in the same birds over time by DXA assisted in the reduction of error in the evaluation of the growth of laying hens. The strains evaluated in this study showed differences in body growth, feathers and components among themselves. And the growth parameters described here are consistent with those found in the literature, and will aid in the improvement of models for calculating nutritional requirements, improving the effectiveness of feeding programs.
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Palavras-chave
Dekalb, Lohmann, Densitometro, Gompertz, curvas de crescimento, growth curves