Investigations into antioxidant effects of rutin supplementation on neonatal Holstein calves and broilers
The purposes of this study were to determine if the naturally occurring flavonoid quercetin, as its glucorhamnoside rutin, has favorable effects on reducing gastrointestinal permeability and reducing susceptibility to hypoxia-induced pulmonary hypertension in neonatal Holstein calves. A 2 x 2 between-subjects factorial design was conducted using Holstein steers (n = 16). Factors included oxygen-level (simulated altitude of 4,572 m versus 975 m) and quercetin supplementation as its glucorhamnoside rutin (4g of quercetin per day versus 0 g per day). Two-days post-arrival (Day 0 of study) the calves were blocked by body mass into treatment groups and both treatments initiated. Pulmonary arterial pressures were measured on Day 12. On Day 14, calves were orally administered lactulose (0.45 g/kg) and mannitol (0.15 g/kg) and serum concentrations of these substances measured by high performance liquid chromatography mass spectrometry four-hours post feeding. Calves were euthanized on Day 15 and tissue sections collected from the lung, liver, jejunum, and ileum for histological evaluation and semi-quantitative scoring of lesions. Hypoxia, but not rutin (P ≥ 0.31), was found to be associated with intestinal permeability. The lactulose-mannitol ratio was 0.54 ± 0.13 in hypoxic calves and 0.02 ± 0.13 in normoxic controls (P = 0.02). Hypoxia (P < 0.001) and, possibly, rutin (P = 0.07) were associated with mean pulmonary arterial pressure. There was a tendency toward a hypoxia-rutin interaction (P = 0.13). Calves fed rutin under hypoxic conditions (mPAP = 59 ± 7 mm Hg) had a lower mPAP than calves that were not fed rutin (mPAP = 80 ± 7 mm Hg) (P = 0.13). Under normoxic conditions calves fed rutin (mPAP = 30 ± 7 mm Hg) had similar mPAP to control calves (mPAP = 28 ± 7 mm Hg). Paradoxically, however, a greater proportion of calves fed rutin had histological evidence of pulmonary arteriolar hypertrophy (P = 0.045) and adventitial hyperplasia (P = 0.01) than negative controls. In conclusion, the findings of this study indicate that hypoxia deleteriously increases intestinal permeability in neonatal calves. The flavonoid quercetin, as its glucorhamnoside rutin, had no protective effect on intestinal permeability and, although it tended to reduce the severity of hypoxia-induced pulmonary hypertension, a greater proportion of calves fed rutin had histological lesions consistent with pulmonary arteriolar remodeling.The purposes of this study were to determine if the natural antioxidants quercetin and curcumin have favorable effects on growth performance and physiology of growing broiler chickens. A completely randomized design was conducted using Cornish x White Rock cross commercial broilers (n = 72). Three weeks after arrival (Day 0 of the study), the birds were randomly divided into four treatment groups: control, quercetin, quercetin plus curcumin (low), and quercetin plus curcumin (high). Oxyhemoglobin saturations and weight of the birds were measured once per week. At six weeks of age the broilers were euthanized, and the hearts of three representative birds from each pen were dissected and weighed for calculation of the right: total ventricular weight ratio (RV:TV ratio). The spleen and liver were also dissected and weighed to compare organ weights across all treatment groups. In addition, feed consumption was measured daily by weighing feed containers each time new feed was added. There were no significant differences in final weights among treatments (P = 0.15). The mean ± SD of the birds at the end of the study (wk. 6) was 2666 ± 316 g. The feeding of antioxidants had no effect on oxyhemoglobin saturation (P = 0.46). Paradoxically, however, oxyhemoglobin saturation increased by two percent per week over the course of the study (P < 0.001). Liver weight (P = 0.31), spleen weight (P = 0.23), and total ventricular weight ratio (P = 0.34) were all not effected by treatment. In addition, feed conversion ratio by week was not found to be different among treatment groups (P = 0.97). The feeding of antioxidants did effect blood antioxidant concentration among treatment groups (P = 0.0001), with controls having the lowest blood antioxidant concentration, followed by low dose quercetin and curcumin, quercetin only group, and finally high dose quercetin and curcumin. In conclusion, the findings of this study suggest that supplementation of the diet fed with quercetin, curcumin, or combination of both did not have a positive effect on growth performance or improve broiler arterial oxyhemoglobin saturation.