The objective of this experimental work was to evaluate the influence of different levels of sorghum grain, as a source of starch, on the plasma parameters of sheep fed elephant grass hay (Pennisetum purpureum Schum). Sorghum grain was included in the diet at four levels: 0, 15, 30 e 45%. Twelve castrated male sheep were assigned to four treatments with three replicates. Six samples of blood per animal were collected just before the morning feeding (zero hour) and after 1, 2, 3, 4, 6 and 8 hours. A completely randomized design was used. The first hour after feeding showed the highest plasma concentration of urea (53.3 mg/100 mL) and was higher than the six and eight-hour samples (49.5 and 49.3 mg/100 mL). The higher concentration of urea in the plasma coincided with the highest concentration of ammonia in the ruminal liquor. Treatment including 30% sorghum in the diet showed a glucose plasmatic concentration of 81,0 mg/100 mL and was superior to the control treatment (60.4 mg/100 mL). Insulin concentration varied among treatments for each hour of collection after feeding according to the levels of sorghum in the diet. The treatment that included 45% sorghum grain showed the highest concentration of this hormone in the plasma. It was observed a peak of the insulin production at the four-hour after feeding.
glucose; grass hay; insulin; sheep; starch; urea
