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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Effect of fiber digestibility and conservation method on feed intake and the ruminal ecosystem of growing steers

Texto completo
Autor(es):
Sousa, D. O. [1] ; Mesquita, B. S. [2] ; Diniz-Magalhaes, J. [1] ; Bueno, I. C. S. [3] ; Mesquita, L. G. [1] ; Silva, L. F. P. [1]
Número total de Autores: 6
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Sch Vet Med, Dept Anim Sci, Sao Paulo - Brazil
[2] Ouro Fino Saude Anim, Sao Paulo - Brazil
[3] Univ Sao Paulo, Fac Anim Sci & Food Engn, Dept Anim Sci, Sao Paulo - Brazil
Número total de Afiliações: 3
Tipo de documento: Artigo Científico
Fonte: JOURNAL OF ANIMAL SCIENCE; v. 92, n. 12, p. 5622-5634, DEC 2014.
Citações Web of Science: 8
Resumo

Fiber digestibility is an important factor regulating DMI in ruminants. Additionally, the ensiling process can also affect digestibility and chemical composition of the forage. The objective of this study was to investigate effects of sugarcane NDF digestibility (NDFD) and conservation method on intake, rumen kinetics, and the ruminal ecosystem of steers. Eight ruminally cannulated Nellore steers (275 +/- 22 kg BW) were used in a replicated 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments. Two sugarcane genotypes divergent for stalk NDFD were used: IAC86-2480 with high NDFD and SP91-1049 with low NDFD. Experimental diets were formulated with 40% sugarcane, either freshly cut or as silage, and 60% concentrate on a DM basis. Each experimental period lasted for 14 d, with the last 4 d used for determination of intake, ruminal evacuation, and ruminal fluid collection. The effect of fiber digestibility on DM and NDF intake was dependent on the forage conservation method (P = 0.01). High NDFD increased (P < 0.01) DMI only when sugarcane was offered as silage, having no effect (P = 0.41) on DMI when offered as freshly cut. Conservation method had no effect on total ruminal mass, with only a tendency (P < 0.10) for greater NDF and indigestible NDF ruminal mass in steers fed the low-NDFD genotype. The NDF turnover and passage rates were greater (P < 0.05) for the genotype with high NDFD but only when offered as silage. Liquid turnover rate in the rumen was greater (P = 0.02) for diets containing silage, with no effect of genotype (P = 0.87). There was no effect of NDFD genotype on ruminal pH (P = 0.77); however, diets containing sugarcane as silage increased (P < 0.01) ruminal pH. Total concentration of short chain fatty acids (P = 0.05) and proportions of propionate (P = 0.01) were greater for diets containing fresh sugarcane. Diets with fresh sugarcane increased the ruminal population of Streptococcus bovis (P < 0.01) and Ruminococcus albus (P = 0.03). The relative population of R. albus was also greater (P = 0.04) for diets containing the sugarcane genotype with high NDFD. Feeding diets containing the sugarcane genotype with high NDFD increased Fibrobacter succinogenes population but only when sugarcane was fed as freshly cut (P = 0.02). Using sugarcane genotypes with high NDFD can increase intake and benefit fiber-degrading bacteria in the rumen. (AU)

Processo FAPESP: 09/00976-2 - Avaliação da importância da digestibilidade da fibra de cana-de-açúcar em dietas de novilhos em crescimento
Beneficiário:Luis Felipe Prada e Silva
Linha de fomento: Auxílio à Pesquisa - Regular