Net energy for maintenance and allometric exponent for poultry
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Data
2020-02-21
Autores
Riveros, Rony [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
E importante uma determinação de um expoente alométrico adequado que considere o crescimento, a maturidade e o status produtivo das aves, e represente melhor o seu tamanho metabólico é importante para expressar de uma forma mais acurada as exigências de energia liquida de mantença para aves em crescimento, aves adultas produtivas e não produtivas. Um estudo de meta analises foi conduzido com o objetivo de estabelecer o coeficiente alométrico para aves de diferentes categorias (aves em crescimento, adultas produtivas e não produtivas), e estimar a energia liquida de mantença. Com esse intuito, um total de 124 dados (produção de calor no jejum, peso corporal, idade, ano de publicação e temperatura), foram analisados tanto na qualidade dos dados quanto nos procedimentos estatísticos de valores influentes e valores atípicos. A agrupação dos dados foi realizada de acordo com a categoria e conferidas pelo analises de clusters. O procedimento do analises dos dados individuais para ajustar o modelo (a×〖BW〗^b) foram feitos considerando pelo efeito ponderado de cada estudo pelo procedimento estadístico PROC MIXED do programa estatístico SAS. Foi observado diferencia estadística das categorias avaliadas com o cálculo de um expoente único, e significativamente diferente com o 0.75 tipicamente utilizada. A ELm diferiu entre as categorias obtendo-se valores de 470, 341, 308 kJ por quilo de peso metabólico para aves em crescimento, galinhas de produção e galos adultos, respetivamente. Utilizar apenas um exponente não é recomendado, decorrente do ajuste de todas as espécies podendo subestimar as exigências de ELm, sendo viável usar a média obtida entre todas as categorias.
It is important to determine an adequate exponent that considers the growth, maturity and the productive status in poultry and has a better representation of metabolic size, to have a more accurate expression of the net energy requirements for growth, adult productive and adult non-productive birds. This study was performed to establish the allometric coefficient of different birds’ categories (growth birds, adult productive and non-productive birds), and estimate the net energy to maintenance. A total of 124 data (fasting heat production, body weight, age, year of publication and temperature) was submitted to several quality and statistical analyses of outlier and leverage points. The criterium to classify the date per category was performed by the cluster analyses. The model a×〖BW〗^b was fitted using individual data, in which the effect of each study was weighted using PROC MIXED procedure of SAS statistical software. The allometric exponent between categories not differ, while statistical difference was observed between when a single exponent was calculated with all data base and 0.75 was tested. The NEm between categories, where 470, 341, and 308 kJ per metabolic weight per day, to growing chicks, laying hens and cockerels, respectively. A single allometric exponent fitted for all category is not recommended, since it could sub-estimate the NEm requirement, thus, an average of allometric exponent obtained from each category should be used.
It is important to determine an adequate exponent that considers the growth, maturity and the productive status in poultry and has a better representation of metabolic size, to have a more accurate expression of the net energy requirements for growth, adult productive and adult non-productive birds. This study was performed to establish the allometric coefficient of different birds’ categories (growth birds, adult productive and non-productive birds), and estimate the net energy to maintenance. A total of 124 data (fasting heat production, body weight, age, year of publication and temperature) was submitted to several quality and statistical analyses of outlier and leverage points. The criterium to classify the date per category was performed by the cluster analyses. The model a×〖BW〗^b was fitted using individual data, in which the effect of each study was weighted using PROC MIXED procedure of SAS statistical software. The allometric exponent between categories not differ, while statistical difference was observed between when a single exponent was calculated with all data base and 0.75 was tested. The NEm between categories, where 470, 341, and 308 kJ per metabolic weight per day, to growing chicks, laying hens and cockerels, respectively. A single allometric exponent fitted for all category is not recommended, since it could sub-estimate the NEm requirement, thus, an average of allometric exponent obtained from each category should be used.
Descrição
Palavras-chave
Taxa metabólica basal, Produção de calor no jejum, Aves em crescimento, Aves adultas, Basal metabolic rate, Fasting heat production, Poultry