Effects Of Different Fat Types And Levels On Growth, Nutrient Utilization And Meat Quality Of Growing Meat Rabbit

Effects of different fat types and levels on growth performance,nutritionutilization,caecum fermentation,digestive enzyme activity in small intestine,meat quality,immunology and biochemical fraits in serum on weaning～2month-old and 2～3 month-old NZ rabbit were investigated. 112 New ZealandWhite rabbits were used to study the influence of dietary added fat and twofeeding stages. Seven diets were formulated:the control diet had no added fat.The other six experimental diets contained of 2%,4%,6% lard and soybeanoil respectively. Other nutrient compositions in the seven dietarys wereidentical. The results were as followd: Experiment One:During weaning～2 month-old ,the increase ofdietary fat level resulted in a higher ADG. accordingly,the feed:gain ratio wasbetter for diets which added fat than the control diet. When the fat additionwas 4%,the ADG and FCR were 29.33g and 3.31:1 seperately.The addition offat did not affect CF coefficients of diets in young rabbits,except fordigestibility of the ME,DN,EE,which increased with the dietary fat levels(p<0.05). When the fat addition was 6%, the value of ME,DN,EE were56.80%,72.76% and 0.86g . In fat addition treatmeants, spleen indices,thymus indices,chymotrypsin activity,amylopsin activity of small intestinewere higher,but had no significant difference compared with control treatment(p>0.05).The lipase activity increased with the fat level significantly andhighest(224.01U/g) when fat added 4% (p<0.05) . The rabbits which fed onthe high level lard diet the concentration of TCH,TG,HDL in serum increasedsignificantly (p<0.05) , whereas the soybean oil restrained the increase of theconcentration of TCH,TG,HDL. The value of pH ,NH3-N content ,acetic 3陈萍:日粮脂肪类型和水平对生长肉兔生长发育,营养物质利用及肉质的影响acid content ,acetone content and butyric acid content was not influentsignificantly by adding fat (p>0.05) , but acetic acid:acetone acid was lowersignificantly in higher added fat treatments (p<0.05) . The types of the fat hadno significance effect in caecum fermentation pattern. Experiment Two:The results of Exp.2 indicated that rabbits fed on dietwhich added fat ,ADG and FCR were improved but had no significance(p>0.05). When the fat addition was 6% ,the ADG and FCR were 25.56g and4.87:1 seperately . The addition of fat did not affect DN,RN,CF digestibilitycoefficients of diets in 2～3 month-old rabbits, except for the digestibility ofME ,EE, which increased with the dietary fat level significantly (p<0.05) .With the increase of the fat level, the spleen indices,thymus indices,enzymeactivity of small intestine improved, but had no significant difference withcontrol group (p>0.05) . Compared with weaning～2 month old, enzymeactivity of small intestine was higher in this stage. With the addition of fat ,thevalue of pH ,the NH3-N content,acetic acid content ,acetone acid contenthad no significant influence with the control treatmeat (p>0.05), except aceticacid content :acetone acid content became lower with the increase of the fatlevel and it got to the minimum in 4% fat level (p<0.05) . The concentration ofTG,TCH,HDL in serum increased significantly in dietary which added lard(p<0.05) , while feeding the dietary which added soybean oil the concentrationof TCH,HDL had no significant change with the control group (p>0.05) . Fatlevel had significant influence on slaughter performance (p<0.05) . Backlongest muscle,longissimus dorsi area,carcass percentage increased with thefat level of dietary. The perirenal fat indices increased with the addition of fatsignificantly (p<0.05) . With the increase of the fat level , the carcasspercentage increased from 46.17% to 52.88% . Effect of diets added fat onpysical indices and chemical composition of meat from rabbits which fed onthe different diets was no significant (p>0.05) . Body fat content increasedsignificantly with fat addition (p<0.05...