Resumen:
The current study aimed to determine the anti-Eimeria efficacy of an extract of grapefruit peels (GF) and
commercial naringenin (NAR) in naturally-infected lambs, as well as the influence of these flavonoids on
the oxidative status during ovine coccidiosis. Pharmacokinetic profiles were also determined. Extracts
were administered per os to Eimeria naturally infected growing lambs during 90 consecutive days. The
commercial anticoccidial drug toltrazuril (TTZ) was included in this trial as a standard. Twenty-four lambs
were divided into four groups: NAR, lambs given a daily dose of 5 mg of a commercial naringenin extract
of 98% higher purity per kg body weight; GF, lambs that recived a daily dose of 5 mg of ethanolic extract of
grapefruit peels per kg body weight; TTZ, lambs treated with 20 mg of toltrazuril/kg body weight on days
0 and 15 of the experiment; and CTRL, untreated lambs that received daily dose of 30 ml of water. Daily
doses of GF and NAR were dissolved in 30 ml of water and orally given to animals; whereas toltrazuril
was administered as a single dose of an undiluted suspension to lambs of the TTZ group. The CTRL group
received 30 ml of water; as well as the TTZ group for the period after the single dose administration. Fecal
and serum samples were collected from all lambs. Anticoccidial efficacy was estimated by coprological
techniques. Generation of nitric oxide levels and the antioxidant capacity of the experimental compounds
were determined by the Griess and ABTS assays, respectively. The pharmacokinetic parameters of NAR
and the GF extract were obtained. On day 30 post-ingestion, anticoccidial efficacy was 91.76% (NAR)
and 89.65% (GF); whereas 99.63% of efficacy was achieved with TTZ 15 days after treatment. NAR, GF
and TTZ significantly reduced oxidative stress in infected animals. The mean daily weight gain for each
group was 122 g (NAR), 122 g (GF), 143 g (TTZ) and 98 g (CTRL). Following the oral administration of NAR
and GF, values in plasma approached maximum concentrations within 2.1 to 2.5 h. In conclusion, the
administration of NAR and the GF extract reduced Eimeria oocyst output, oxidative stress and promoted
higher mean daily weight gains in infected lambs.
