RESUMO
BACKGROUND: Boars fed a mixed form of inorganic and organic iron in excess of the NRC recommended levels still develop anemia, which suggested that the current level and form of iron supplementation in boar diets may be inappropriate. Therefore, 56 healthy Topeka E line boars aged 15-21 months were randomly divided into 5 groups: basal diet supplemented with 96 mg/kg ferrous sulfate (FeSO4) and 54 mg/kg glycine chelated iron (Gly-Fe, control); 80 mg/kg or 115 mg/kg Gly-Fe; 80 mg/kg or 115 mg/kg methionine hydroxyl analogue chelated iron (MHA-Fe, from Calimet-Fe) for 16 weeks. The effects of dietary iron supplementation with different sources and levels on semen quality in boars were investigated. RESULTS: 1) Serum Fe and hemoglobin concentrations were not affected by reduced dietary iron levels in the 80 mg/kg or 115 mg/kg Gly-Fe and MHA-Fe groups compared with the control group (P > 0.05). 2) Serum interleukin-6 (IL-6) and sperm malondialdehyde (MDA) levels in the 80 mg/kg or 115 mg/kg MHA-Fe groups were lower than those in the control group (P < 0.05), and higher serum superoxide dismutase levels and lower MDA levels in the 115 mg/kg MHA-Fe group (P < 0.05). 3) Boars in the 80 mg/kg or 115 mg/kg Gly-Fe and MHA-Fe groups had lower serum hepcidin (P < 0.01), ferritin (P < 0.05), and transferrin receptor (P < 0.01) concentrations, and boars in the 115 mg/kg MHA-Fe group had higher seminal plasma Fe concentrations compared with the control group. 4) Boars in the 80 mg/kg and 115 mg/kg MHA-Fe groups had lower abnormal sperm rate and in situ oscillating sperm ratio compared to the control group at weeks 12 and/or 16 of the trial. However, the effect of Gly-Fe on improving semen quality in boars was not evident. 5) Serum IL-6 level was positively correlated with hepcidin concentration (P < 0.05), which in turn was significantly positively correlated with abnormal sperm rate (P < 0.05). Furthermore, significant correlations were also found between indicators of iron status and oxidative stress and semen quality parameters. CONCLUSIONS: Dietary supplementation with 80 mg/kg or 115 mg/kg MHA-Fe did not induce iron deficiency, but rather reduced serum inflammatory levels and hepcidin concentration, alleviated oxidative stress, increased body iron utilization, and improved semen quality in adult boars.
RESUMO
This study aimed to explore whether empathy with nature (i.e., the tendency to understand and share the emotional experience of the natural world) contributes to pro-environmental attitudes in early childhood. In a correlational investigation (Study 1), 138 (Mage = 57.78 months) preschool children completed a battery of tasks to measure their pro-environmental attitudes, empathy with nature, and empathy with humans. We found that empathy with nature positively predicts pro-environmental attitudes, even beyond the predictive power of empathy with humans. In a quasi-experimental investigation (Study 2), 46 children from two parallel classes in the same preschool were recruited as the intervention (n = 23, Mage = 66.74 months) and control (n = 23, Mage = 67.61 months) groups. An intervention session that aimed to induce empathy with nature was applied to the intervention group, whereas an active control teaching session was applied to the control group. After the intervention, the intervention group demonstrated greater pro-environmental attitudes than did the control group. Together, our studies provide converging evidence that empathy with nature promotes pro-environmental attitudes in early childhood, further implying the value of integrating empathy with nature in early childhood environmental education.
