Detalhes bibliográficos
| Ano de defesa: |
2019 |
| Autor(a) principal: |
SOUZA, Rayanne Thalita de Almeida
 |
| Orientador(a): |
SANTOS, Mércia Virginia Ferreira dos |
| Banca de defesa: |
MELLO, Alexandre Carneiro Leão de,
SILVA, Valdson José da,
SILVA, Dulciene Karla de Andrade,
SILVA, Maria da Conceição |
| Tipo de documento: |
Tese
|
| Tipo de acesso: |
Acesso aberto |
| Idioma: |
por |
| Instituição de defesa: |
Universidade Federal Rural de Pernambuco
|
| Programa de Pós-Graduação: |
Programa de Pós-Graduação em Zootecnia
|
| Departamento: |
Departamento de Zootecnia
|
| País: |
Brasil
|
| Palavras-chave em Português: |
|
| Área do conhecimento CNPq: |
|
| Link de acesso: |
http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/8414
|
Resumo: |
Environmental and management factors affect throughout the plant development period the anatomical and nutritive characteristics of forage. The objective of this research was to evaluate the effect of elephant grass genotypes of different size associated with the presence and absence of irrigation, in the dry and rainy season on the nutritive value, in vitro gas production and anatomical aspects in the leaf blade and stem. The experiment was carried in Garanhuns/Pernambuco, during the years 2017 and 2018. The experimental design was in randomized blocks, with split plot scheme. The main plots consisted in the presence or absence of irrigation and the subplots four genotypes of elephant grass (Mott, Taiwan A-146 2.37, Elefante B e IRI-381). Plant samples were taken in the rainy (August) and dry season (December). Chemical bromatological analyzes, in vitro digestibility of dry matter, in vitro gas production and anatomical analyzes were performed on leaf blades and stems. In the leaf blades was showed that Mott expressed significantly lesser NDF (588.98 g kg-1 DM) (P ≤ 0.05) than Taiwan A-146 2.37 (598. 22 g kg-1 DM) and the high-size genotypes (668.26 g kg-1 DM) did not differ from each other. In the presence of irrigation there was a significant effect (P ≤ 0.05) only in the dry season with greater deposition of fibrous components in the leaf blades. In the stems, there was a significant difference (P ≤ 0.05) in the non-irrigated treatment with greatee NDF (709.16 g kg-1 DM) and lower IVDMD (377.94 g kg-1 DM) in the rainy season when compared to dry season, which had lesser NDF content and greater DIVMS, respectively (648.63 g kg-1 DM, 410.82 g kg-1 DM). The C fraction of the carbohydrates in the leaf blades did not differ between the genotypes, however with irrigation this fraction increased by 20%. There was a greater proportion of the B1 + B2 fraction of the nitrogen compounds in the plants without irrigation. The volume of gas obtained through the degradation of the fibrous carbohydrates, it was significantly greater in the stem, than to the leaf blades, especially in the high-size genotypes. The proportion of adaxial and abaxial leaf blades epidermis of leaf blades varied significantly (P ≤ 0.05) between the genotypes. There were a significant interaction (P ≤ 0.05) between irrigation and genotypes, and between genotypes and season to sclerenchymatic tissue in leaf blades. Regards the vascular sheath in the leaf blades, there was an isolated effect of the genotypes (P ≤ 0.05) and it was observed that the highest and lowest proportion of vascular sheath was recorded, respectively, in the Mott (19.93%), and IRI 381 (14.65%) and did not differ from the Taiwan A-146 2.37 (17.42%) and Elefante B (17.98%). For the proportion of parenchyma in stems, there was an isolated effect (P ≤ 0.05) between the genotypes, a greater parenchyma area was recorded in the stem of the small-size genotypes (57.35%), which was different significantly from the high-size (52.05%). The indigestible carbohydrates, NDF, ADF and lignin presented strong negative correlations with mesophyll and positive with sclerenchymatic tissue, while the carbohydrates of rapid rumen degradation and in vitro digestibility of the dry matter showed positive correlations with the mesophyll. Small-size genotypes have better nutritive value when compared to high-size genotypes. The lesser nutritive value of the genotypes under irrigation may indicate that the cutoff frequency should be higher due to the effects of water on the growth of genotypes, especially in the high-size genotypes. The rainy season and the presence of irrigation provide larger areas of degradation slow tissue or indigestible. Estimates of the proportions of mesophyll, xylem, associated fibers and sclerenchyma combined with chemical composition improves the estimation of nutritive value. |
