A Comparative Study On Growth Performance,Cecal Microflora,Cecal Metabolomics,Behavior,and Meat Quality Of Sichuan White Rex Rabbits And Hyla Rabbits

Under the background of the global epidemic,the Rex rabbit market is in a downturn due to the influence of many factors,such as the sluggish international economic situation,the restriction of the world fur industry,the concept of green and environmental protection development,and the overproduction of fur in the early stage,leading to the lack of confidence in breeding Rex rabbits.On the contrary,with the improvement of rabbit meat processing technology,the promotion and popularization of rabbit meat knowledge,and the change of public consumption concepts,the consumption of rabbit meat is constantly increasing,and the price of rabbit meat is also steadily rising.There is strong market demand for meat rabbits,and breeding meat rabbits has become one of the more popular breeding projects now.The purpose of this experiment was conducted to compare the differences in growth performance,slaughter performance,intestinal morphology,serum biochemical indices,cecal microflora,cecal metabolomics,behavior and meat quality between Sichuan White Rex rabbits and Hyla rabbits,and to comprehensively understand the characteristics of these two breeds.It was considered that Rex rabbits might be fed and slaughtered according to the meat rabbit model,so as to provide a new way to alleviate the current market depression of Rex rabbits.A total of 144 male weaned rabbits at 35 days old,half from Sichuan White Rex rabbits and half from Hyla rabbits,were used in this study.Each group was divided into 24 replicates,with 3 rabbits in each replicate.The experiment lasted for 40 days,including 7 days of pre-feeding and 33 days of trial.During the experiment,the same diet and feeding management modes were used.The initial body weight,final body weight and daily feed intake of rabbits were recorded,and average daily gain,average daily feed intake and feed to meat ratio were calculated.Rabbit behavioral changes were observed 24 hours before slaughter.The slaughter performance,intestinal morphology,serum biochemical indices,cecal microflora,cecal metabolomics and meat quality of 75-day-old rabbits were analyzed.The results showed that:（1）The initial weight,final weight,average daily gain and average daily feed intake of the Sichuan White Rex rabbit group were significantly lower than those of the Hyla rabbit group（P<0.05）,and the feed to meat ratio was significantly higher than that of the Hyla rabbit group（P<0.05）.（2）The skin index,head index,abdominal fat index and perirenal fat index in Sichuan White Rex rabbit group were significantly higher in Hyla rabbit group（P<0.05）,while small intestine index,cecum index,colon index,heart index and liver index were significantly lower in Hyla rabbit group（P<0.05）.The length of the small intestine and colon was significantly shorter in Sichuan White Rex rabbit group than in Hyla rabbit group（P<0.05）.（3）The villus height,villus height and crypt depth ratio in the jejunum of Sichuan White Rex rabbit group were significantly lower than those of Hyla rabbit group（P<0.05）,while the crypt depth of Sichuan White Rex rabbit group was significantly higher than that of Hyla rabbit group（P<0.05）.（4）The serum blood glucose content of Sichuan White Rex rabbit group was significantly lower than that of Hyla rabbit group（P<0.05）,but there was no significant difference in other indicators（P>0.05）.（5）There was no significant difference in cecal microbial Alpha diversity between the Sichuan White Rex rabbit group and the Hyla rabbit group（P>0.05）.（6）Firmicutes and Bacteroidetes were the dominant bacteria in the Sichuan White Rex rabbit group and the Hyla rabbit group.The main dominant genera of the two groups included uncultured＿bacterium＿f＿Muribaculaceae,uncultured＿bacterium＿f＿Eubacteriaceae,Akkermansia,Ruminococcaceae＿NK4A214＿group and Ruminococ-caceae＿UCG-014.（7）At the phylum level,Synergistetes and Spirochaetes were significantly higher in Sichuan White Rex rabbit group than in Hyla rabbit group（P<0.05）,but Cyanobacteria was significantly lower in Hyla rabbit group（P<0.05）.At the genus level,the abundances of 10 species of bacteria were significantly higher and the abundances of 8 species of bacteria were significantly lower in Sichuan White Rex rabbit group than in Hyla rabbit group（P<0.05）.（8）ABC transporter and tryptophan metabolism were the most significantly enriched pathways of differential metabolites.（9）The Sichuan White Rex rabbit group showed longer lying and caecotrophy durations,but shorter feeding,sitting,and biting durations（P<0.05）.The frequencies of sniffing and caecotrophy behaviors were higher（P<0.05）,but sitting,allogrooming,and biting frequencies were lower in the Sichuan White Rex rabbit group（P<0.05）.（10）The values of L*,b*and WHC of longissimus dorsi muscle in Sichuan White Rex rabbit group were significantly higher than those in Hyla rabbit group（P<0.05）,and the values of p H_{24 h} and a*were significantly lower than those in Hyla rabbit group（P<0.05）.The L*value and b*value of biceps femoris muscle in Sichuan White Rex rabbit group were significantly higher than those in Hyla rabbit group（P<0.05）,while p H_{24 h},a*value and cooking loss were significantly lower than those in Hyla rabbit group（P<0.05）.In conclusion,the growth performance and the stereotyped behavior of Sichuan White Rex rabbit are lower than those of Hyla rabbit.Sichuan White Rex rabbit and Hyla rabbit have their own advantages in meat quality.When the Rex rabbit market is depressed,Sichuan White Rex rabbit can be raised according to the way of meat rabbit breeding,and slaughtered in advance at the age of 2-3 months,which can effectively alleviate the current situation of the Rex rabbit market downturn.