Biochemical and hormonal parameters of lambs using guava (Psidium guajava L.) agro-industrial waste in the diet.

The objective of this research was to evaluate the biochemical and hormonal parameters of Santa Inês sheep that received diets with different levels of guava agro-industrial waste (GAW). Forty non-castrated male animals of the Santa Inês breed were used, with an average initial weight of 21.3 ± 2.6 kg, and an average age of 120 days. The animals were distributed in a completely randomized design, with five treatments and eight replicates, and fed with increasing GAW levels replacing hay (0.0, 7.5, 15.0, 22.5 and 30.0%). After the beginning of the diet period, blood samples were collected every 2 weeks approximately 3 h after feeding. Cholesterol concentration had a significant effect (P < 0.01) with the inclusion of GAW. The animals that ingested the control diet had the highest concentrations of cholesterol. T3 and T4 hormones showed a significant difference (P < 0.01) among the treatments, i.e. the animals that ingested the control diet had the lowest concentrations of these hormones. We concluded that the inclusion of GAW in up to 30% decreases the concentration of cholesterol and increases the concentrations of T3 and T4 in the blood, aiding the metabolism of the animals.