Effects Of Coprophagy On Growth Performance,Hair Production Performance In Angora Long-haired Rabbits And The Transcriptome Sequencing Analysis Of Skin

Rabbits gradually develop fecal behavior after starting to feed,which is the instinctive reaction of rabbits to food.Unlike the feces of other animal,this behavior of rabbits is not a pathological phenomenon,but a normal physiological phenomenon,which has important physiological significance for rabbits themselves.Rabbits have a special colonic separation mechanism to produce two kinds of feces with different nutrient contents,and rabbits have physiological behaviors of eating feces with higher nutrient.Rabbits eat soft feces,repeatedly use various nutrients,re-synthesize high-quality protein and water-soluble vitamins,improve the utilization of potassium and sodium,and improve feed conversion efficiency.The fecal behavior of rabbits was first discovered and reported by Morot in 1882.Later,there were some studies,but the effect of fecal behavior on the performance of rabbits and its specific mechanism are still unclear.In the preliminary experiments of this laboratory,it was found that the prohibition of feces had a significant effect on the growth performance and reproductive performance of New Zealand white rabbits.In order to explore the extent and causes of the effects of fecal behavior on the growth of animal fur,the following two aspects were studied using Angora long-haired rabbits:Research 1:Effect of coprophagy on growth performance and hair production performance of Angora long-haired rabbitIn order to explore the effects of fecal behavior on growth performance and hair production performance of rabbits,Angola long-haired rabbits with hair-producing were selected as test subjects,and feeding experiments were conducted using a method that prohibits feces.We divided 48 female Angola long-haired rabbits,which were sheared,into three groups:group A was a coprophagy prohibited group(CP group),a wide collar was used to prohibit feces;group B was a coprophagy allowed group.(CA group),wearing a narrow collar without forbidding feces;group C was a control group without a collar(CON group),normal feeding.The formal test was started after the preliminary test 5 days.the feed intake was recorded daily,and the weight of each individual and the growth of rabbit’s hair were measured every 10 days.After the first hair production cycle(70 d),the hair production of each individual was determined.Six long-haired rabbits were randomly selected for slaughter in each group,skin tissue samples were collected,and slaughter performance was determined.Continuing to raise the long-haired rabbits with a hair production cycle(90d),record the same as above.The research results are as follows:(1)The coprophagy has a significant effect on the growth performance of long-haired rabbits.The prohibition of feces can significantly reduce the average daily gain and final weight of Angora long-haired rabbits(P<0.05),and the effect can be restored by restoring a hair production cycle.(2)The coprophagy had a significant effect on the hairiness of long-haired rabbits.The prohibition of feces can significantly reduce the rabbit hair production of Angora long-haired rabbits(P<0.05),in which the hair follicle density was significantly reduced(P<0.01),and the hair follicle diameter was significantly increased(P<0.01).The recovery of the feces in a hairy cycle did not fully recover(P>0.05).(3)The coprophagy has an effect on the slaughter performance of long-haired rabbits but is not significant enough.The prohibition of fences reduced the net weight and semi-net weight of Angora long-haired rabbits(P>0.05).Research 2:Transcriptome analysis of skin tissue in Angora long-haired rabbitsThrough research one we found that coprophagy has a significant effect on the hair production performance of Angora long-haired rabbits.To further verify the molecular mechanism of the effects of fecal behavior on the hairiness of Angora long-haired rabbits,we randomly selected three long-haired rabbit’s skin tissue samples from each of the slaughtered individuals in research one,and then performed high-throughput transcriptome sequencing analysis.The research results are as follows:(1)Through the RNA-Sequencing of skin tissue samples from three treatment groups of Angora long-haired rabbits,we found 541 differentially expressed genes(DEGs),of which CP vs CA,CP vs CON and CA vs CON were 310,211 and 204,respectively.The 310 differential genes of CP vs CA are mainly enriched in protein secretion,immune function,enzyme activity and the signaling pathways related to hair follicle growth,immune response and cancer.(2)10 DEGs were analyzed by real-time quantitative PCR.The expression trends of these 10 DEGs were consistent with the sequencing results,and the linear regression results of RNA-Seq and qPCR in the foldchange of CP vs CA and CON vs CA were well correlated(r2=0.94),which demonstrates that the RNA-Seq results of this assay are reliable.In summary,this study found that the coprophagy has a significant effect on the growth performance and hair production performance of Angora long-haired rabbits.The prohibition of feces can significantly reduce the daily gain and hair production of long-haired rabbits.Through the comparative analysis of three groups of skin tissue’s transcriptome sequencing,it was found that the differential genes were highly correlated with protein secretion and immune function,and related candidate genes were screened to predict whether they directly or indirectly regulate hair growth of long-haired rabbits.The transcriptome sequencing of skin tissue is a preliminary exploration of the effect of coprophagy on the molecular network related to the growth of hair follicles in rabbits.The results of this study provide an important theoretical reference for the use of molecular breeding techniques to improve the quality of long-haired rabbit fibers and increase the yield of rabbit hair,which plays an important role in promoting the development of the rabbit industry.