Growth curves of the visceral organs of Saanen goats
Carregando...
Data
2017-07-10
Autores
Andrade, Marina Elizabeth Barbosa [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Este trabalho foi realizado utilizando informações de 7 estudos, em que foram ajustadas curvas de crescimento ao desenvolvimento dos órgãos do sistema visceral de fêmeas, machos castrados e machos inteiros da raça Saanen de 0,5 a 19,5 meses de idade. Inicialmente, foram avaliados oito modelos: Regressão linear simples; Quadrático; Monomolecular; Brody; Von Bertalanffy; Logística; Gompertz; e Richards. Os dados dos órgãos viscerais (fígado, pâncreas, baço, rúmen-retículo, omaso, abomaso, intestino delgado e intestino grosso) e tecido adiposo mesentérico (TAM), foram ajustados nos modelos usando o procedimento NLMIXED do SAS. O melhor modelo ajustado foi escolhido com base no Critério de Informações Akaike corrigido para pequenas amostras (AICc) e nos coeficientes de correlação de concordância (CCC). Após a escolha do modelo que melhor ajustou a curva de crescimento dos órgãos viscerais avaliados, modelamos a variância buscando um melhor ajuste. Os parâmetros dos modelos para cada sexo foram comparados utilizando o comando CONTRAST (p < 0,10). Em geral, o modelo que melhor descreveu o crescimento de órgãos do sistema visceral foi o logístico (menor AICc e maior CCC). Quando os órgãos foram expressos em gramas, o sexo não influenciou os parâmetros das equações para predição do crescimento dos órgãos avaliados (p > 0,10), exceto o MAT (p < 0,02); em que as fêmeas apresentaram menor taxa de deposição comparada aos machos inteiros e castrados (0,318 ± 0,034 vs 0,659 ± 0,062), e um ponto de inflexão superior ao dos machos inteiros e castrados (7,7 vs 3,7 meses). No entanto, essa diferença entre os sexos não é encontrada quando o MAT é expresso em % ao peso do corpo vazio (PCV). Independentemente do sexo, no início do crescimento, o fígado representou 2,75 ± 0,113 % do PCV, cresceu (g) a uma taxa máxima de 0,531 ± 0,062, e o ponto de inflexão de sua curva ocorreu em 1,7 meses. O trato gastrointestinal (TGI) representou 9,14 ± 0,493 % PCV, e à medida que os animais cresceram o TGI diminuiu sua porcentagem em relação ao PCV a uma taxa constante de 0,135 ± 0,046 %. Considerando o período avaliado, em geral, o rúmen-retículo e o intestino grosso aumentaram sua porcentagem em relação ao PCV e TGI, enquanto o abomaso e o intestino delgado diminuíram sua porcentagem em relação ao PCV e TGI, à medida que o animal crescia. O rúmen-retículo e o intestino grosso, que estão diretamente relacionados à digestão de alimentos sólidos, apresentaram maiores taxas de crescimento nos dois primeiros meses de vida. Os resultados evidenciaram que o sexo não afeta o crescimento de órgãos do sistema visceral (g), exceto para MAT, porém, quando olhamos em % PCV alguns órgãos mostram diferenças entre os sexos, como o fígado, abomaso, intestino delgado, intestino grosso e intestinos. O conhecimento da curva de crescimento dos órgãos viscerais pode ser muito útil para melhorar a compreensão de seu impacto sobre as exigências nutricionais desses animais, e ser utilizado para otimizar ou desenvolver um plano nutricional adequado para cada fase de crescimento, como também auxiliar os produtores a desenvolver planos estratégicos em um rebanho de caprinos, como a melhor idade para desmame e abate desses animais.
This work was performed gathering information of 7 studies, in which growth curves were fitted to the visceral organs of female, intact male, and castrated male Saanen goats from 0.5 to 19.5 months old. Initially, eight models were assessed: Monomolecular; Simple linear regression; Quadratic; Monomolecular; Brody; Von Bertalanffy; Logistics; Gompertz; and Richards. Data of the visceral organs (liver, pancreas, spleen, rumen-reticulum, omasum, abomasum, small intestine, and large intestine) and mesenteric adipose tissue (MAT) were fitted in the models using NLMIXED procedure of SAS. The best fitted model was choosing based on the Akaike Corrected Information Criterion for small samples (AICc) and values and the concordance correlation coefficient (CCC). After choosing the model that best fitted the growth curve of the evaluated visceral organs, we modelled the variance seeking a better fit. Parameters of the models for each sex were compared using the CONTRAST statement (p < 0.10). Overall, the model that best described visceral organ growth was the logistic (i.e., lower AICc and higher CCC). When organs were expressed in grams, the sex did not influence the parameters of equations to predict the growth of the evaluated organs (p > 0.10), except for TAM (p < 0.02); females presented a lower deposition rate compared to intact males and castrated males (0.318 ± 0.034 vs 0.659 ± 0.062), and a inflection point higher than intact males and castrated males (7.65 vs 3.69 months). However, this difference between the sexes is not found when TAM is expressed in % to empty body weight (EBW). Irrespective of sex, at the beginning of growth, liver stood for 2.75 ± 0.113 % of EBW, grew (g) at a maximum rate of 0.531 ± 0.062, and its inflection point of the curve occurred at 1.7 months. The gastrointestinal tract (GIT) stood for 9.14 ± 0.493 % EBW, and as the goats grew the GIT decreased its percentage in relation to the EBW at a constant rate of 0.135 ± 0.046 %. Considering the evaluated period, in general rumen-reticulum and large intestine increased their percentage in relation to EBW and GIT, whereas abomasum and small intestine decreased their percentage in relation to EBW and GIT, as animal grew. The rumen-reticulum and large intestine, which are directly related to the digestion of solid foods, presented higher growth rates in the first two months of life. The results highlighted that sex does not affect the growth of visceral organs (g), except for TAM. However, when we look at % EBW, some organs show differences between the sexes, such as the liver, abomasum, small intestine, large intestine and Intestines. Knowledge of the growth curve of the visceral organs can be very useful in improving the understanding of their impact on the nutritional requirements of these animals and can be used to optimize or develop a nutritional plan suitable for each growth phase, but also to help producers develop strategic plans for a herd of goats, such as the best age for weaning and slaughtering these animals.
This work was performed gathering information of 7 studies, in which growth curves were fitted to the visceral organs of female, intact male, and castrated male Saanen goats from 0.5 to 19.5 months old. Initially, eight models were assessed: Monomolecular; Simple linear regression; Quadratic; Monomolecular; Brody; Von Bertalanffy; Logistics; Gompertz; and Richards. Data of the visceral organs (liver, pancreas, spleen, rumen-reticulum, omasum, abomasum, small intestine, and large intestine) and mesenteric adipose tissue (MAT) were fitted in the models using NLMIXED procedure of SAS. The best fitted model was choosing based on the Akaike Corrected Information Criterion for small samples (AICc) and values and the concordance correlation coefficient (CCC). After choosing the model that best fitted the growth curve of the evaluated visceral organs, we modelled the variance seeking a better fit. Parameters of the models for each sex were compared using the CONTRAST statement (p < 0.10). Overall, the model that best described visceral organ growth was the logistic (i.e., lower AICc and higher CCC). When organs were expressed in grams, the sex did not influence the parameters of equations to predict the growth of the evaluated organs (p > 0.10), except for TAM (p < 0.02); females presented a lower deposition rate compared to intact males and castrated males (0.318 ± 0.034 vs 0.659 ± 0.062), and a inflection point higher than intact males and castrated males (7.65 vs 3.69 months). However, this difference between the sexes is not found when TAM is expressed in % to empty body weight (EBW). Irrespective of sex, at the beginning of growth, liver stood for 2.75 ± 0.113 % of EBW, grew (g) at a maximum rate of 0.531 ± 0.062, and its inflection point of the curve occurred at 1.7 months. The gastrointestinal tract (GIT) stood for 9.14 ± 0.493 % EBW, and as the goats grew the GIT decreased its percentage in relation to the EBW at a constant rate of 0.135 ± 0.046 %. Considering the evaluated period, in general rumen-reticulum and large intestine increased their percentage in relation to EBW and GIT, whereas abomasum and small intestine decreased their percentage in relation to EBW and GIT, as animal grew. The rumen-reticulum and large intestine, which are directly related to the digestion of solid foods, presented higher growth rates in the first two months of life. The results highlighted that sex does not affect the growth of visceral organs (g), except for TAM. However, when we look at % EBW, some organs show differences between the sexes, such as the liver, abomasum, small intestine, large intestine and Intestines. Knowledge of the growth curve of the visceral organs can be very useful in improving the understanding of their impact on the nutritional requirements of these animals and can be used to optimize or develop a nutritional plan suitable for each growth phase, but also to help producers develop strategic plans for a herd of goats, such as the best age for weaning and slaughtering these animals.
Descrição
Palavras-chave
Estômagos, Fígado, Intestinos, Tecido adiposo mesentérico, Trato gastrointestinal, Intestines, Gastrointestinal tract, Liver, Mesenteric adipose tissue, Stomachs