Analysis Of Production Performance And FecB Gene Distribution In F1 Generation Of Duohu Hybrid

The Duolang sheep was a local meat-producing sheep breed in Xinjiang,characterized by fast growth,high meat production,and excellent meat quality,but its reproductive performance was relatively poor.The Hu sheep,on the other hand,was a prolific multi-lambing breed of sheep in China that exhibits a high reproductive rate and year-round estrus.By crossing Duolang and Hu sheep,the hybrid offspring could leverage the potential advantages of both breeds,with the aim of improving the reproductive performance of their offspring while also enhancing their meat-producing abilities.Objective:This study used Duolang sheep as the paternal parent and Hu sheep as the maternal parent to perform hybridization.By comparing the physiological and biochemical indicators,body weight and size,slaughter performance,meat quality,and reproductive hormones of the F1 hybrid and purebred Hu sheep,this study aimed to establish the optimal regression model for the body weight and size of the F1 hybrid,and to analyze the distribution of FecB genotypes in the Duohu F1 generation.The results would provide a theoretical basis for the selection of high-quality offspring in the hybridization of Duolang and Hu sheep.Methods:（1）Physiological indicators of 6-month-old Duohu F1 generation sheep and Hu sheep were measured,and the blood physical and chemical indexes of the two groups were compared and analyzed in serum.（2）The weight,body length,body height,chest circumference,and cannon circumference of Duo Hu F1 generation sheep and Hu sheep were measured from birth to 6 months of age.A linear regression model of body weight for 6-month-old Duo Hu F1 generation sheep and Hu sheep was constructed.The slaughter performance and meat quality of 6-month-old Duohu F1 sheep and Hu sheep were measured.Serum of Duohu F1 sheep ewe and Hu sheep ewe in an estrous cycle was collected once a day,and the hormone levels of FSH and E₂ were measured.（3）Blood samples from Duo Hu F1 generation sheep and Hu sheep were collected,and PCR-RFLP technology was used to detect the FecB genotypes of the two groups of sheep.Results:（1）Although there were slight differences in physiological and blood biochemical parameters between the 6-month-old Multibreed F1 sheep and the Hu sheep,all parameters were within the normal range for sheep.（2）Compared to the Hu sheep,the Duohu F1 sheep had significantly higher birth weight（P<0.05）,and their weight was significantly higher than that of Hu sheep from 3 to 6 months of age（P<0.01）,while there was no significant difference in weight between the two groups at 1 and 2 months of age.Additionally,the Duohu F1 sheep had significantly greater body length,body height,chest girth,and cannon circumference than the Hu sheep from birth to 3 months of age（P<0.05）,and the differences in these parameters were extremely significant from 4 to 6 months of age（P<0.01）.The optimal regression model for the 6-month-old Duohu F1 ram weight was Y=0.647X₁+0.554X₂+0.336X₃-16.676,while the optimal regression model for the Duohu F1 ewe weight was Y=0.709X₁+1.105X₂+0.318X₃-27.62.The Duohu F1 sheep had significantly higher live weight,carcass weight,and dressing percentage than the Hu sheep at 6 months of age（P<0.01）,and the eye muscle width and area were significantly different between the two groups（P<0.05）,while there was no significant difference in GR value and eye muscle length between the two groups（P>0.05）.The meat color score of the Duohu F1 sheep was significantly higher than that of the Hu sheep（P<0.05）,while the marbling score,shear force,p H,and water loss were not significantly different between the two groups.During the estrous cycle,the serum FSH and E₂ of Duohu F1 sheep ewes and Hu sheep ewes showed a trend of increasing at first and then decreasing.（3）In the F1generation of Duohu sheep,two genotypes of the FecB gene,B+and++,were detected.There was no significant difference in body weight and body size between the BB and B+genotypes of the F1 generation of Duohu sheep at 3 and 6 months of age（P>0.05）.However,the lambing rate of the B+genotype in the F1generation of Duohu sheep was significantly higher than that of the++genotype（P<0.05）.Conclusion:When crossbreeding between Duolang sheep and Hu sheep,their offspring showed remarkable heterosis in terms of body weight and measurement,slaughter performance and meat quality,which provided theoretical basis for the breeding of excellent offspring of multi-lake hybridization.