Effects Of Two Unconventional Feed Ingredients On Redox Status And Lipid Metabolism Of Pigs And Chickens

With the growth of China’s population and the improvement of people’s living standards,people’s demand for animal products has also increased.However,there has been some competition in the use of traditional feed resources as livestock and poultry and human food ingredients.On the other hand,in modern intensive production,changes in environmental temperature,decreased feed intake,and dysregulation of the body’s metabolic activity will cause certain pressure on animals,resulting in increased active oxygen and oxidative stress.Oxidative stress can cause cholesterol to deposit on the walls of blood vessels,which can disturb lipid metabolism;in turn,lipid accumulation can also induce oxidative stress.Therefore,it is of great significance to seek unconventional feed resources that can increase animal antioxidant capacity and reduce body lipid deposition.Defatted rice bran is a by-product of the production of rice bran oil by the leaching method,which has a high energy value and has some active ingredients such as inositol,y-oryzanol and tocotrienol.Xanthoceras sorbifolia Bunge meal is a by-product after de-oiling fromXanthoceras sorbifolia Bunge,with a protein content of 62.04%,many types of amino acids,and rich in various active ingredients.It has yet to be developed as a high-quality protein source.Studies hace shown that active ingredients such as inositol and saponin have the effect of anti-oxidation and improving the body’s lipid metabolism.In the early stage of our laboratory,the effects of defatted rice bran and Xanthoceras ifolia Bunge meal on the performance,nutrient digestibility and intestinal microorganisms of pigs and chickens were studied.Therefore,this article aims to investigate the effects of defatted rice bran and Xanthoceras sorbifolia Bunge meal on redox status and lipid metabolism of pigs and chickens,respectively.The experiment is divided into three parts:Experiment 1.Effects of Partial Replacement of Corn with Different Levels of Defatted Rice Bran on Redox State and Cholesterol Metabolism of Suhuai PigsThe purpose of this study was to investigate the effects of partial replacement of corn with different levels of defatted rice bran on redox state and cholesterol metabolism of Suhuai castrated boars.A total of 21 healthy Suhuai castrated boars with similar body weight of（62.90± 1.12）kg were randomly divided into control group（test group Ⅰ）,test group Ⅱ and test group Ⅲ,with 7 replicates per group and 1 pig per replicate.Pigs in the test group Ⅰ were fed a basal diet,and those in the test group Ⅱ and test group Ⅲ were fed the basal diets replaced corn with 14%and 28%defatted rice bran,respectively.Soybean meal,bran and soybean oil,etc.were used to balance the digestible energy,crude protein and amino acid levels among the basal diet and the two experimental diets.The adaption period was 10 days,and the experiment period was 28 days.The results showed as follows:the serum malondialdehyde（MDA）content of Suhuai pigs in the test group Ⅱand test group Ⅲ were significantly lower than that in the test group Ⅰ（P<0.05）;compared with the test group Ⅰ and test group Ⅲ,the serum catalase（CAT）activity of Suhuai pigs in the test group Ⅱ was significantly higher（P<0.05）;Suhuai pigs in the test group Ⅲ had the highest activity of CuZn superoxide dismutase（CuZn-SOD）in serum,which was significantly different from that in the test group Ⅰ（P<0.05）;the liver glutathione（GSH）content and the ratio of glutathione to oxidized glutathione（GSH/GSSG）of Suhuai pigs in the test group Ⅲ was significantly higher than those in the test group Ⅰ（P<0.05）.Compared with the test group Ⅰ,the serum content of total cholesterol（TC）and low-density lipoprotein cholesterol（LDL-C）of Suhuai pigs in the test group Ⅲ was significantly higher（P<0.05）;there was no significant difference in the contents of liver TC and triglyceride（TG）among all groups（P>0.05）.Diets with defatted rice bran partially replacement of corn had no significant effect on the mRNA expression levels of cholesterol-7alpha-hydroxylase（CYP7αl）and cholesterol-27alpha-hydroxylase（CYP27α1）in the liver of Suhuai pigs（P>0.05）;the mRNA expression levels of 3-hydroxy-3-methylglutaryl coenzyme A reductase（HMGCR）,sterol regulatory element binding protein-2（SREBP-2）and scaveger receptor class B type Ⅰ（SR-BI）in the liver of Suhuai pigs in the test group Ⅱ and the test group Ⅲ was significantly lower than those in the test group Ⅰ（P<0.05）.In addition,Suhuai pigs in the test group Ⅲ had the lowest mRNA expression level of low density lipoprotein receptor（LDLR）in the liver,which was significantly different from that in the test group Ⅰ（P<0.05）.Correlation analysis between serum contents of TC and LDL-C with oxidation markers and antioxidant enzymes in serum and liver of Suhuai pigs showed that serum TC levels in the same individual was positively correlated with liver GSH content and GSH/GSSG（P<0.05）.There was an significant positive correlation between serum LDL-C level and liver GSH content as well as GSH/GSSG（P<0.01）.In summary,under the conditions of this experiment,partial replacement of corn with different levels of defatted rice bran in the diet may improve the antioxidant capacity,and affect the cholesterol metabolism in serum and liver,and cholesterol-related gene expression in liver of Suhuai pigs.Experiment 2.Effects of Xanthoceras sorbifolia Bunge meal Substituting Soybean meal on Lipid Metabolism of Broilers from 21-42 Days.The purpose of this experiment was to investigate the effects of Xanthoceras sorbifolia Bunge meal substituting soybean meal on lipid metabolism of broilers from 21-42 days.A total of 192 healthy 21-day-old AA broilers with similar body weight were selected and randomly divided into 3 groups:the groups C（corn-soybean meal basic diet）,group L（Xanthoceras sorbifolia Bunge meal replacing 50%soybean meal in the basic diet）and group H（Xanthoceras sorbifolia Bunge meal replacing 100%soybean meal in the basic diet）,with 8 replicates per group and 8 chickens in each replicate（half male and half female）.The trial period was 21 days.At the end of the test,one of the healthy males was randomly selected from each of the three groups to slaughter for sampling,collecting blood,liver,abdominal fat and breast muscle tissue to determine the serum biochemical indexs,slaughter performance,liver cholesterol（TC）and triglyceride（TG）levels,the expression of genes responsible for lipid metabolism at mRNA levels in the liver and fatty acid composition of breast muscles.The results showed that the body weight,eviscerated weight,liver weight and breast muscle weight of the group H were significantly lower than the other two groups（P<0.05）.Compared with group C,there were no significant changes in the body weight,eviscerated weight,liver weight and breast muscle weight of broiler in group L（P>0.05）.In addition,compared with the control group,the replacement of soybean meal with different levels of Xanthoceras sorbifolia Bunge meal significantly reduced the abdominal fat weight of broilers（P<0.05）;while the L group had a lower abdominal fat rate than the C group（P<0.05）.Replacing of soybean meal with different levels of Xanthoceras sorbiolia Bunge meal significantly reduced serum TG,TC and high-density lipoprotein cholesterol（HDL-C）levels of broilers（P<0.05）,but had no significant effect on liver TC and TG contents（P>0.05）.The mRNA expression level of liver cholesterol metabolism-related gene showed that:the mRNA expression level of cholesterol-7alpha-hydroxylase（CYP7α1）in the liver of broilers in the group H was significantly higher than that in the control group（P<0.05）;the mRNA expression level of cholesterol-27alpha-hydroxylase（CYP27α1）in the group L was the highest,and it was significantly different from the other two groups（P<0.05）;meanwhile,compared with the control group,the mRNA expression level of low density lipoprotein receptor（LDLR）in the group L was significantly increased（P<0.05）.The mRNA expression level of liver lipid metabolism-related gene showed that:compared with the other two groups,the mRNA expression level of sterol regulatory element binding protein-1C（SREBP-1C）in the group H was significantly decreased（P<0.05）;compared with the C group,broilers in the H group tended to have decreased the mRNA expression level of acetyl CoA carboxylase（ACC）（P=0.066）;in addition,the mRNA expression levels of carnitine palmitoyl transferase I（CPTI）and peroxisome pro liferator-activated receptors alpha（PPARα）in the L group were significantly higher than those in the control group（P<0.05）;the replacement of Soybean meal with different levels of Xanthoceras sorbifolia Bunge meal had no significant effect on the mRNA expression of other lipid metabolism genes（P>0.05）.Fatty acid composition in breast muscle of broilers showed that:the replacement of soybean meal with different levels of Xanthoceras sorbifolia Bunge meal significantly reduced palmitic acid（C16 0）content（P<0.05）,and increased the content of polyunsaturated fatty acids in the breast muscle（P<0.05）,among them,the content of eicosadienoic acid（C202）increased significantly（P<0.05）,and the content of linoleic acid（C18:2）showed an upward trend（P=0.09）;the content of eicosenoic acid（C20:1）and docosaenoic acid（C22:1）in the breast muscle of broilers increased significantly compared with the control group（P<0.05）.In summary,the replacement of soybean meal with Xanthoceras sorbifolia Bunge meal significantly increased the PUFA content in muscle,improved the serum lipid levels of broiler,and promoted fat mobilization by enhancing mRNA expression of liver fat and cholesterol degrading related enzymes,thereby reducing fat deposition.Experiment 3.Effects of Xanthoceras sorbifolia Bunge meal Substituting Soybean meal on Redox State of Broilers from 21-42 Days.The purpose of this experiment was to investigate the e ffects of partial replacement of soybean meal with different levels of meal on the redox state of serum,liver and breast muscle in broilers.Experimental design was the same as experiment 2.The results showed that:serum total superoxide dismutase（T-SOD）,liver catalase（CAT）and the breast muscle glutathione peroxidase（GSH-PX）levels of broilers were the lowest in the group H,and were significantly different from the other two groups（P<0.05）.The liver T-SOD levels in the gro up H were also significantly lower than those in the group C（P<0.05）.However,the replacement of soybean meal with different levels of Xanthoceras sorbifolia Bunge meal had no significant effects on other antioxidant enzymes in serum,liver and breast muscle of broilers（P>0.05）.The results of correlation analysis showed that serum and liver T-SOD activities were significant positive correlated with serum total cholesterol（TC）and triglyceride（TG）levels,respectively（P<0.05）;broiler liver CAT activity was significant negative correlated with the muscle eicosene acid（C20:1）and docosaenoic acid（C22:1）content（P<0.01）;the T-SOD activity of broiler liver was significant negative correlated with muscle C22:1 and polyunsaturated fatty acid content（P<0.05）,significantly positive correlated with palmitoleic acid（C16:1）content（P<0.05）;;breast muscle GSH-PX activity was significant negative correlated with C20:1 and eicosadienoic acid（C202）content（P<0.05）,which was significant negative correlated with C22:1 content（P<0.01）.Broiler serum TC and TG contents were significantly positively correlated with breast muscle palmitic acid（C16 0）（P<0.05）,and significantly negative correlated with unsaturated fatty acids such as C20:1,C22:1 and C202（P<0.05）;There is no correlation between other indicators（P>0.05）.In summary,the replacement of soybean meal by Xanthoceras sorbifolia Bunge meal reduced the antioxidant enzyme activity;in addition,the change of the antioxidant enzyme activity has a certain correlation with serum lipid metabolism indexes and breast muscle fatty acid levels.