Abstract
Background This study investigated the effects of inorganic and organic minerals on physiological responses,oxida-tive stress reduction,and rumen microbiota in Holstein bull calves(123.81±9.76 kg;5 months old)during short-term heat stress(HS)and recovery periods.Eight Holstein calves were randomly assigned to four treatment groups:no min-eral supplementation(Con),inorganic minerals(IM),organic minerals(OM),and high-concentration organic miner-als(HOM)and two thermal environments(HS and recovery)using 4×2 factorial arrangement in a crossover design of four periods of 35 d.Calves were maintained in a temperature-controlled barn.The experimental period consisted of 14 d of HS,14 d of recovery condititon,and a 7-d washing period.Results Body temperature and respiration rate were higher in HS than in the recovery conditions(P＜0.05).Sele-nium concentration in serum was high in the HOM-supplemented calves in both HS(90.38 μg/dL)and recovery periods(102.00 μg/dL)(P＜0.05).During the HS period,the serum cortisol was 20.26 ng/mL in the HOM group,which was 5.60 ng/mL lower than in the control group(P＜0.05).The total antioxidant status was the highest in the OM group(2.71 mmol Trolox equivalent/L),followed by the HOM group during HS,whereas it was highest in the HOM group(2.58 mmol Trolox equivalent/L)during the recovery period(P＜0.05).Plasma malondialdehyde and HSP70 levels were decreased by HOM supplementation during the HS and recovery periods,whereas SOD and GPX levels were not significantly affected(P＞0.05).The principal coordinate analysis represented that the overall rumen micro-biota was not influenced by mineral supplementation;however,temperature-induced microbial structure shifts were indicated(PERMANOVA:P＜0.05).At the phylum level,Firmicutes and Actinobacteria decreased,whereas Fibrobacte-res,Spirochaetes,and Tenericutes increased(P＜0.05),under HS conditions.The genus Treponema increased under HS conditions,while Christensenella was higher in recovery conditions(P＜0.05).Conclusion HOM supplementation during HS reduced cortisol concentrations and increased total antioxidant status in Holstein bull calves,suggesting that high organic mineral supplementation may alleviate the adverse effects of HS.
基金项目
Cooperative Research Program for Agriculture Science and Technology Development(PJ015039032023)
Rural Development Administration,Republic of Korea()
国家科技期刊平台
NSTL
万方数据