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.

Evaluation of nutritive value and in vitro rumen fermentation gas accumulation of de-oiled algal residues

Background：Algae are widely recognized for their high oil content and for exponentially accumulating biomass with particular potential to provide single cell protein for human consumption or animal feed.It is believed that along with biodiesel from algae,the high protein de-oiled algal residue may become an alternative feed supplement option in the future.This study was conducted to investigate de-oiled algal residue obtained from the common Chlorella species,Thalassiosira weissflogii,Selenarstrum capricornutum,Scenedesmus sp.,and Scenedesmus dimorphus for assessment as potential feed supplements for ruminants by comparing with soybean（Glycine max） meal and alfalfa（Medicago sativa） hay.Results：With the exception of T.weissflogii,algal residue had higher concentrations of Cu,Zn,and Mn and lower concentration of Ca,Mg,and K than soybean meal and alfalfa hay.The algal residue CP（crude protein）concentrations ranged from 140 to 445 g/kg DM and varied among the de-oiled residues.In vitro rumen fermentation gas accumulation curves indicated that algal biomass degradation potential was less than that of soybean meal or alfalfa hay by up to 41.7%.The gas production curve,interpreted with a dual pool logistic model,confirmed that the fraction sizes for fast fermenting and slow fermenting of de-oiled algal residues were smaller than those in soybean meal and alfalfa hay,and the fermenting rate of the fractions was also low.Conclusions：Inferior in vitro rumen gas accumulation from the five de-oiled algal residues suggests that these algal byproducts are less degradable in the rumen.

Use of nanoscale metals in poultry diet as a mineral feed additive

The research was aimed at studying the efficiency of a nanoscale alloy of copper(Cu) and zinc(Zn) to be used as a mineral additive for feeding broiler chickens,compared to inorganic and organic forms of these elements.Biochemical studies of the blood serum were performed using an automated analyzer.The mineral composition was determined by atomic emission and mass spectrometry(MS-ISP),The study was performed on broiler chickens of cross Smena 7(n=72) in the conditions of a vivarium.There were3 treatment groups with 24 chickens in each.Replacing the inorganic form of mineral supplements with the nanosized alloy resulted in a positive productive effect,with a tendency to increasing the content of serum protein.The nano scale form of metals improved(P <0.05) the activity of aminotransferases.At the same time,the liver micro structure of experimental groups is similar to that of the control.There was a moderate plethora and poor polymorphoncellular infiltration around the interlobular triads with a clear morphological orga nization of the stromal and parenchymal co mponents of the liver.However,the lack of oxidative stress was confirmed by the dynamics of catalase(CT),total superoxide dismutase(TSOD) and malondialdehyde(MDA) levels,and the concentrations of which did not exceed the reference level Replacing Cu and Zn sulfates with the nanoscale alloy(group 1) and organic form(group 2) of these elements in the diet of broiler chickens was accompanied by the increasing pool of these elements in the organisms at the end of the experiment.Copper was accumulated throughout the experiment in experimental group 1,compared to the reference,with the maximum difference in the liver of 36.5%(P ≤ 0.05),in the feathers 2.5 times(P ≤ 0.01).Assessment of the Zn level dynamics in the feathers revealed a well noticeable tendency to reducing its concentrations during the experiment in all groups.Against the background of feeding a nanoscale alloy,Zn concentration in the liver exceeded the reference by 66.8%(P ≤ 0.01) only at the end of the experiment.Thus,nanoscale forms of Cu and Zn have a cumulative effect,and may become an alternative to inorganic and organic forms of these elements in poultry nutrition.