| The wide application of artificial insemination technology has greatly improved the utilization rate of boar semen.Moreover,the quality of semen is tightly related to the conception rate of sows;therefore,it is essential to maintain the quality of semen storage in vitro.However,boar semen is susceptible to oxidative damage during preservation due to the inability to remove excess reactive oxygen species in time,which results in a decrease in semen quality.Furthermore,the quality of the collected boar semen also affects its preservation,and its quality has been reported to be inseparable from the supply of nutritious diets.Probiotic fermentation feed,which is a new type of green and high-efficiency antimicrobial-free feed,has been widely used in livestock and poultry production.The reason for using probiotic fermentation feed is that it has various functions,including improving ABTS and DPPH free radical scavenging activity,increasing feed utilization,promoting animal growth,and enhancing the body's antioxidant capacity.Nevertheless,the research on the quality of probiotic fermentation feed for boar semen has not been reported.Thus,this experiment explored the effects of compound probiotic fermentation feed on boar immune function and semen quality,and assessed the nutritional value and bacterial diversity of feed before and after fermentation.A total of 12 large white boars were randomly divided into two groups,and the control group was fed with basal diet,while the experimental group was provided with compound probiotic fermentation feed.During the whole feeding experiment,boar blood physiological and biochemical indexes,immune function and semen quality related indicators were detected,which provided theoretical basis and realistic reference for the production and application of compound probiotic fermentation feed in breeding boars.The main results obtained in this study are as follows:1.The nutrient composition of the feed before and after fermentation of the probiotics was changed.Compared to control,the content of crude protein in the experiment group was significantly increased by 16.13%(P<0.01).Moreover,the content of crude ash,crude fiber,neutral detergent fiber and acid detergent fiber in the experimental group was significantly lower than that in the control group(P<0.01),which was reduced by 38.02%,36.76%,44.03%,and 44.69%,respectively.The fat content was significantly lower than the control group(P<0.05),which was reduced by 31.03%.The content of total amino acid and umami amino acid in the experimental group was significantly higher than that in the control group(P<0.05),which increased by 7.02% and 11.26%,respectively,among which aspartic acid,threonine,serine and glutamic acid.Glycine,alanine,proline and phenylalanine were increased by 6.78%,7.89%,12.64%,16.24%,8.24%,13.08%,24.39%,20.21%,respectively.The average relative abundance of the dominant genus of Lactobacillus,Enterococcus,Clostridium,Weissella,Klebsiella and Pediococcus was significantly higher in the test group after fermentation than in the control group(P<0.01).2.The serum levels of BUN,NEUT and NEUTP in the experimental group were significantly lower than those in the control group(P<0.05),which were decreased by 26.48%,29.21% and 18.34%,respectively.The blood levels of WRC and MCV in the experimental group were significantly higher than those in the control group(P<0.05),which increased by 33.62% and 6.65%,respectively.In addition,serum IgA and IgM levels in the test showed an increasing trend compared with the control group(P>0.05).All values are within the normal range.3.On the 60 th and 120 th day of the experiment,the sperm density and sperm motility of the experimental group were significantly higher than those of the control group(P<0.01).Additionally,the acrosome integrity rate,plasma membrane integrity rate and sperm mitochondrial membrane potential activity in the experimental group were significantly higher than those in the control group(P<0.05).There was no significant difference in ejaculation volume and total sperm number per ejaculation between the experimental group and the control group during the whole experimental period.4.On the 120 th day of the experiment,the MDA content and ROS level in the semen of the experimental group were significantly lower than those of the control group(P<0.01),which decreased by 27.34% and 37.60%,respectively.In comparison with control group,the content of fructose in the seminal plasma of the experimental group was significantly increased by 17.11%(P<0.01).During the whole trial period,there was no significant effect of total antioxidant capacity,testosterone content and porcine sperm adhesion protein gene mRNA expression in the experimental and control groups(P>0.05).In summary,the use of compound probiotic fermentation can significantly improve the nutritional value of the feed and the diversity of beneficial bacteria.Feeding compound probiotic fermented feed can enhance the immunity of boars,effectively improve sperm motility,acrosome integrity,plasma membrane integrity,mitochondrial membrane potential as well as antioxidant capacity of semen,thereby reducing lipid peroxidation damage of sperm,and ultimately improving the semen quality of boars. |
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