Potencial nutricional do feno de capim arroz (echinochloa sp) através da caracterização química, da digestão e do fluxo visceral líquido de oxigênio em ovinos

Abstract

This study was conducted to evaluate the change of chemical composition on rice grass Echinochloa crusgalli hay harvestad of 32, 46, 72 and 90 days of regrowth, and its effect on intake, digestibility, ruminal fermentation passage kinetics of solid phase through gastrointestinal tract (Experiment 1) and oxygen utilization by the visceral system in sheeps. In experiment 1 eight castrated lambs (mean live weight of 33± 3,3kg) were used in a 4 X 4 Latin Square double experimental design. .Experiment 2 was realized in two assays, using three castrated lambs fed CA cut with 46, 72 and 90 days of regrowth, with mean live weight of 38± 5 e 35± 4kg (in assay 1 and 2 respectively). These animals were chronically catheterized of portal, hepatic and mesenteric veins. Experimental diets were hay fed twice a day ad libitum . Intake of hay components linearly decreased P<0,05) with the increase of the regrowth age of the plant with the ecxeption of indigestible neutral detergent fiber were similar between treatments (P<0,05). Aparent digestibility of no nitrogen compounds of the hay, and aparent and true nitrogen digestibility, urinary excretion, N retention and microbial protein synthesis were linearly decreased (P<0,05) with the increase of the regrowth age of the plant. Sugar and aminoacids concentrations linearly decreased (P<0,05), but peptides concentrations were cuadratically releated with the increase of regrowth age of CA (P<0,05). pH values and N-amonia concentrations were similar between the treatments. Retention times in the caecumcolon were similar between the treatments. The passage rate of solid phase and retention time in the reticulo-rumen, and retention time of solid phase through gastrointestinal tract were cuadratically related with the regrowth age of CA. The nutritional value of the hay of grass rice was affected negatively by the age of regrowth of the plant. The consumption was limited by the fiber consumption in of indigestible neutral detergent, but it was not related with the passage rate of solid phase through gastrointestinal tract of the animals. Around 9% and 19% of the consumption of energy metabolic it was liberated as heat by the organs that compose the systems portal and visceral, respectively, directly related with the hay consumption and of nutrients, but not with the maturity of the plant.