| Lard has a certain nutritional value and is rich in polyunsaturated fatty acids,but long-term intake can also cause damage to the animal’s body,causing the animal’s body to produce excessive lipid peroxides.The trace element selenium is one of the important elements to maintain the antioxidant performance of the animal body.This experiment is mainly to study the effects of adding lard and different levels of sodium selenite to the diet on growth performance,antioxidant performance and muscle fatty acid composition,in order to explore better feeding nutrition standards for rex rabbits.This experiment was designed to divide 60 healthy,weaned rex rabbits with no difference in body weight(P>0.05)into four groups randomly,and were fed different diets: standard feed(CON group),feed supplemented with 5% lard(HFD group),feed supplemented with 5% lard and 0.5 mg/kg sodium selenite(LSE group)and feed supplemented with 5% lard and 1 mg/kg sodium selenite(HSE group).The test indicators for measuring the test rex rabbits include growth performance,slaughter performance,muscle nutrient composition,muscle fatty acid composition,liver GPx enzyme activity and its gene expression.Test one:During the breeding period,the rex rabbits were weighed every 7 days for 12 weeks.experiment result shows:The rabbits fed the lard-supplemented feed exhibited improved performance,as demonstrated by increases in the final body weight,daily weight gain and carcass weight and a reduced feed conversion rate(P<0.05).Compared with the control group,the daily gain of otter rabbits in each experimental group increased by 14.3%,25.2%,and 11.7%,respectively.The feed conversion rate of the otter rabbits in each experimental group and the control group were reduced by 13.2%,20.6%,and 9.9%,respectively.Supplementation with lard and selenium did not significantly affect the serum levels of triglycerides,low-density lipoprotein cholesterol and total protein in Rex rabbits compared with the levels found in the control group(P>0.05)but significantly increased the levels of serum cholesterol and globulin(P<0.05)and significantly decreased the levels of high-density lipoprotein cholesterol and albumin(P<0.05).Test two:Selenium supplementation significantly increased the selenium content in muscles(P<0.05),and lard supplementation significantly increased the muscle fat content(P<0.05),whereas supplementation with lard and selenium had no significant effect on the muscle moisture,crude protein and ash(P>0.05).When 0.5 mg/kg sodium selenite was added to the diet,the selenium deposition in the muscle tissue of the rex rabbit reached the highest value.With the increase of the selenium concentration,the selenium deposition did not increase.In addition,the lard and selenium supplemented diets significantly increased the levels of monounsaturated fatty acids and polyunsaturated fatty acids in muscle(P<0.05)and significantly decreased the levels of saturated fatty acids(P<0.05).When 5% lard was added to the diet,the polyunsaturated fatty acids in the muscle tissue of the rex rabbit increased by3.3%.Test three:Supplementation of the diet with lard and selenium enhanced the gene expression of glutathione peroxidase in the liver of Rex rabbits,and particular enhancement was detected in the groups fed a diet supplemented with selenium(P<0.05).Supplementation of the diet with lard increased the muscle lipid oxidation index(thiobarbituric acid-reactive substances),whereas supplementation with selenium synergistically decreased the lipid oxidation index(P<0.05).The addition of lard and sodium selenite to feed can improve the reproductive performance and fatty acid composition of rex rabbits and does not negatively affect the health of the animals.In summary,adding 5% lard and 0.5mg/kg sodium selenite to the rex rabbit’s diet will not adversely affect the growth of the rex rabbit,but will make the growth performance better.Also improved its meat quality. |
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