Effect of organic mineral supplementation in reducing oxidative stress in Holstein calves during short‑term heat stress and recovery conditions

Background This study investigated the effects of inorganic and organic minerals on physiological responses,oxidative 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 mineral supplementation(Con),inorganic minerals(IM),organic minerals(OM),and high-concentration organic minerals(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).Selenium concentration in serum was high in the HOM-supplemented calves in both HS(90.38μg/dL)and recovery periods(102.00μg/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 microbiota 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 Fibrobacteres,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.

Can Dietary Pomegranate Peels Reduce Stress Responses Associated with Group Mixing of Holstein Beef Calves？

The study investigated whether dietary CPE （concentrated pomegranate peel extract） may mitigate the negative effects associated with group mixing prior to marketing and enhance beef meat quality. Twenty-two bull calves were reared in triplets and divided to control （n = 9） and CPE-treated （n = 13） groups. CPE was supplemented during eight months of rearing, and calves were mixed 34 d prior to marketing to control and treatment groups. Calves were monitored for weight gain, rumination, activity, metabolic and oxidative stress responses, Finally, meat quality traits were examined. The results find that pre-mixing activity （P 〈 0.0001）, non-esterifies fatty acids （P = 0.02） and plasma testosterone （P = 0.005） levels were higher in the treatment group. Following mixing, activity （P 〈 0.0001 ） and plasma anti-oxidative capacity （P = 0.05） increased in the treatment compared to the control group. In spite of the above, dietary supplementation of CPE didn＇t reveal improvement of meat quality parameters by means of meat pH and shelf life It indicated that improved serum anti-oxidant capacity in the CPE calves was not sufficient to prevent the mixing effects on meat quality. A combined CPE concentration and mixing management should be examined in order to reduce mixing related effects on meat quality.