Effects Of BHT Addition In Oxidized Soybean Oil Diet On Growth Performance,Meat Quality And Liver Function Of Yellow-Feathered Broilers

Oil is the most direct and important energy-supplying substance in broiler growth.Vegetable oils and fats are rich in unsaturated fatty acids,which can promote the absorption of lipids in feeds,provide essential fatty acids for livestock and improve the composition of muscle fatty acids.However,oils and fats have the characteristics of being easily oxidized,and oxidized oils can harm the health of livestock and poultry and affect the quality of livestock and poultry products Therefore,the oxidation of fats and oils in feed has become a problem that cannot be ignored.Butylated hydroxytoluene(BHT)is an extremely widely used phenolic antioxidant,which has stable and highly effective antioxidant properties in vitro.It has been found that BHT also has excellent antioxidant properties in vivo.it plays a role in the metabolism of the body.This study was to investigate the antioxidant activity of BHT in vitro and its effects on the growth performance,meat quality,antioxidant and lipid metabolism in vivo.In order to provide scientific reference for the application of BHT in the production of yellow-feathered broilers.This study is divided into two parts in vitro and in vivo:Experiment 1 was conducted in vitro to study the effects of different concentrations of BHT on the antioxidant capacity of lipids and the antioxidant activity of BHT.(1)Using the Schaal oven method,different concentrations of BHT were used as the research object,and the oxidation degree of the oil group containing BHT concentrations of 0%,0.01%,0.0125%,0.015%,0.0175%and 0.02%was compared.(2)Analysis and comparison of BHT,BHA,VE and DL-α-tocopherol Several in vitro antioxidant activities for the production of common antioxidants.The results showed that:(1)With the prolongation of oxidation time,different concentrations of BHT can significantly inhibit the oxidation of oils.0.0125%BHT can be the optimum concentration to inhibit the increase of lipid peroxidation(POV),acid value(AV)and anisidine value(p-AV).(2)Compared with the fat-soluble antioxidants BHA,VE and DL-α-tocopherol commonly used in production,BHT showed strong oxidation activity and stability in ABTS·+clearance,iron ion reducing power and inhibition of yolk lipid peroxidation.Experiment 2 was conducted in vivo to study the effects of BHT addition in oxidized soybean oil diet on growth performance,meat quality and liver function of yellow-feathered broilers.Using a two-factor test design,factor 1 is the soybean oil in the diet,which is divided into(fresh soybean oil,MDA=13.4 nmol/mL;oxidized soybean oil,MDA=367.7 nmol/mL),factor 2 is the BHT content in the diet.According to the amount of additives,it is divided into two levels(0 mg/kg;125 mg/kg).In this experiment,240 1-day-old high quality yellow-feathered broilers were randomly divided into 4 groups,6 replicates in each group,and 10 chickens in each group were fed with fresh soybean oil diet without BHT(F-CON group).Fresh soybean oil diet with 125 mg/kg BHT(F-BHT group),fed with oxidized soybean oil diet without BHT(O-CON group),oxidized soybean oil diet with 125 mg/kg BHT(O-BHT group).The test period was 58 days.1 The effects of BHT addition in oxidized soybean oil diet on growth performance and meat quality of yellow-feathered broilersThe results showed that:(1)Compared with the fresh soybean oil group,oxidized soybean oil had a tendency to reduce the average daily gain(ADG)(P=0.052)and average daily feed intake(ADFI)(P=0.062)of yellow-feathered broilers.Compared with the BHT-free diet group,ADG(P=0.083)and terminal weight(FBW)(P=0.082)of the yellow-feathered broilers in the BHT-containing diet group showed an increasing trend.(2)Compared with the fresh soybean oil group,oxidized soybean oil significantly reduced the spleen and thymus index of yellow-feathered broilers(P<0.05).Compared with the BHT-free diet group,the addition of BHT in the diet significantly attenuated the spleen index of yellow-feathered broilers caused by oxidized soybean oil(P<0.05).(3)Compared with the fresh soybean oil group,oxidized soybean oil significantly increased the 24 h drip loss,48 h drip loss and malondialdehyde(MDA)content in the breast muscle of yellow-feathered broilers(P<0.05).Compared with the diet group without BHT,the addition of BHT in the diet significantly reduced the 24 h drip loss,cooking loss and MDA content of the pectoral muscle(P<0.05).(4)Compared with the diet group without BHT,the addition of BHT in the diet can improve the antioxidant capacity of the pectoral muscle and stabilize the meat quality by inhibiting OH·,and alleviate the adverse effects caused by the oxidized soybean oil on the quality of the yellow-feathered broilers.2 The effects of BHT addition in oxidized soybean oil diet on the antioxidant capacity of liver and breast muscle of yellow-feathered broilersThe results showed that:(1)Compared with the fresh soybean oil group,the contents of alanine aminotransferase(ALT)and aspartate aminotransferase(AST)in the oxidized soybean oil group were significantly increased(P<0.05).Compared with the BHT-free diet group,the addition of BHT in the diet significantly attenuated the significant increase in serum ALT and AST levels caused by oxidized soybean oil(P<0.05).(2)Compared with the fresh soybean oil group,the superoxide enzyme(SOD)activity and total antioxidant capacity(T-AOC)in the liver tissue of the oxidized soybean oil group were significantly lower(P<0.05).Compared with the BHT-free diet group,the addition of BHT in the diet significantly increased the T-AOC level in the liver(P<0.05),and significantly attenuated the decrease in SOD activity in the liver caused by oxidized soybean oil(P<0.05).(3)Compared with the fresh soybean oil group,the MDA content in the liver tissue of the oxidized soybean oil group was significantly increased P<0.05).Compared with the BHT-free diet group,the MDA content in the liver of the yellow-feathered broilers fed with BHT diet was significantly lower(P<0.05).(4)Compared with the fresh soybean oil group,the mitochondrial MDA content in the liver of the oxidized soybean oil group was significantly increased(P<0.05),and the total superoxide dismutase(T-SOD)content was significantly decreased(P<0.05).Compared with the BHT-free diet group,the addition of BHT in the diet significantly attenuated the significant increase in MDA content in the liver mitochondria caused by oxidized soybean oil(P<0.05)and a significant decrease in T-SOD activity(P<0.05).(5)Compared with fresh soybean oil group,nuclear transcription factor 2(Nrf2),y-glutamyl cysteine ligase regulatory subunit(y-GCLm)and y-glutamine in the liver of oxidized soybean oil group,the expression of acyl-cysteine ligase catalytic subunit(γ-GCLc)mRNA was significantly decreased(P<0.05).Compared with the BHT-free diet group,the addition of BHT in the diet significantly attenuated the decrease in Nrf2,γ-GCLm and γ-GCLc mRNA expression caused by oxidized soybean oil(P<0.05),and significantly increased the expression level of SOD1 and CAT mRNA in liver.(P<0.05).(6)Compared with the BHT-free diet group,the addition of BHT in the diet significantly increased the CAT activity of the breast muscle of the yellow-feathered broilers(P<0.05).(7)Compared with the fresh soybean oil group,the content of CAT mRNA in the oxidized soybean oil group was significantly decreased(P<0.05).Compared with the BHT-free diet group,the addition of BHT in the diet significantly reduced the expression of CAT mRNA in the breast muscle caused by oxidized soybean oil(P<0.05),and significantly increased the expression of Nrf2 and SOD1 mRNA in the breast muscle(P<0.05).3 The effects of BHT addition in oxidized soybean oil diet on hepatic lipid metabolism and energy metabolism in yellow-feathered broilersThe results showed that:(1)Compared with the fresh soybean oil group,the serum triglyceride(TG)content in the oxidized soybean oil group was significantly lower(P<0.05)and the levels of high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C)were also significantly reduced(P<0.05).Compared with the BHT-free diet group,the addition of BHT in the diet significantly attenuated the decrease the level of HDL-C in serum caused by oxidized soybean oil(P<0.05).(2)Compared with fresh soybean oil group,the gene expressions of sterol regulatory element binding protein-1(SREBP-1),fatty acid synthase(FAS),malic enzyme(ME),acetyl-CoA carboxylase(ACC),hydroxy-3-methylglutaryl coenzyme A reductase(HMGC)and apolipoprotein B(APOB)in the liver of oxidized soybean oil group were significantly decreased(P<0.05).Compared with the BHT-free diet group,the addition of BHT in the diet significantly increased the expression of APOA1 mRNA in the liver of yellow-feathered broilers(P<0.05).(3)Compared with the fresh soybean oil group,the content of malate dehydrogenase(MDH)and succinate dehydrogenase(SDH)in the liver mitochondria of the oxidized soybean oil group was significantly increased(P<0.05).Compared with the BHT-free diet group,the addition of BHT in the diet significantly increased the MDH content in the liver mitochondria of the yellow-feathered broilers(P<0.05).(4)Compared with the fresh soybean oil group,the activities of mitochondrial complex II and V in the liver of the oxidized soybean oil group were significantly increased(P<0.05).Compared with the BHT-free diet group,the addition of BHT in the diet significantly increased the activities of liver mitochondrial complex Ⅳand V in yellow-feathered broilers(P<0.05).(5)Compared with the BHT-free diet group,the addition of BHT in the diet significantly increased the ATP content in the liver of yellow-feathered broilers(P<0.05).(6)Compared with the fresh soybean oil group,the expression of silencing regulator 1(SIRT1)mRNA and mitochondrial gene(mtDNA)in the liver of the oxidized soybean oil group were significantly lower(P<0.05).Compared with the BHT-free diet group,the addition of BHT in the diet significantly increased the expression of SIRT1 and MDH2 mRNA and mitochondrial mtDNA in the liver of yellow-feathered broilers(P<0.05).In summary:BHT can exhibit strong antioxidant activity and stability in vitro through its hydrogen supply electron supply mode,and 0.0125%of the added amount is the optimum concentration for inhibiting lipid peroxidation in vitro.Oxidized soybean oil diet not only has a tendency to reduce the growth performance of yellow feather broilers,but also significantly reduces its meat quality and antioxidant capacity,affecting its lipid metabolism and energy utilization.BHT can improve the breast muscle quality of the yellow-feathered broiler by enhancing muscle free radical scavenging ability,and reducing MDA content.BHT can alleviate the oxidative damage caused by oxidized soybean oil diet to yellow-feathered broilers by regulating the expression of antioxidant-related genes in the pectoral muscle and liver,increasing the activity of CAT in the breast muscle and the activities of CAT and SOD in the liver.BHT can alleviate lipid metabolism and energy metabolism abnormalities of yellow-feathered broilers caused by oxidized soybean oil diet by regulating the expression of lipid metabolism and energy metabolism related genes,mitochondrial tricarboxylic acid cycle enzymes and activities of respiratory chain complex enzymes.