Effects Of Different Rearing Methods And Residual Feed Intake On Growth Performance,Slaughter Performance,and Meat Quality Of Small-sized Meat Ducks

In poultry production,feed cost accounts for more than 70%of the total costs,where feed efficiency is closely related to breeding cost.Therefore,it is of great significance to reduce poultry feed intake and improve feed efficiency to decrease production costs of breeding enterprises.Residual feed intake（RFI）is an ideal indicator to measure the feed efficiency of poultry,which is moderately heritable and is helpful for genetic selection of high-quality animals with high feed efficiency.In this study,the small-sized meat ducks（"Yiyang Line 1"）jointly cultivated by our research group and Shuyang Zhongke Breeding Poultry Co.Ltd,were used as the research object to conduct comparative experiments on growth performance,slaughter performance and meat quality of small-sized meat ducks under different rearing methods,in order to choose the optimum rearing method for their growth and development.The correlation between residual feed intake and growth performance,slaughter performance,meat quality and serum biochemical indexes was analyzed.The main results are as follows:1.Effects of different rearing methods on growth performance,slaughter performance and meat quality of small-sized meat ducksTo study the effects of different rearing methods on growth performance,slaughter performance and meat quality of small-sized meat ducks.A total of 420 healthy 21-day-old ducks were randomly assigned to two treatment groups（net cage and ground）with 6 replicates（half male and half female）in each treatment group.During the experiment（22-63 days）,all individuals were measured for growth performance,and 3 male and 3 female ducks were randomly selected from each replicate for slaughter test at 63 days of age to determine slaughter performance and meat quality.The results showed,in terms of growth performance,body weight at 63 days of age（BW63）,average daily feed intake（ADFI）and average daily gain（ADG）in the net cage group were higher than those in the ground flat group（P<0.05）,while there was no significant difference in feed conversion rate（FCR,F/G）（P>0.05）.In terms of slaughter performance,the percentage of abdominal fat in net cage group was significantly higher than that in ground cage group（P<0.05）,and the percentage of muscle and stomach was significantly lower than that of flat ground group（P<0.05）.In terms of meat quality and nutritional composition,compared with flat rearing group,the breast muscle L*value,pHi,pH24,shear force,moisture content and intramural fat content of ducks in net rearing group were higher（P<0.05）,breast muscle pH24 and intraminomuscle fat content were higher,shear force,water loss rate and water content were lower in cage group（P<0.05）.In addition,lower pH1 and higher pH24,lower shear force and higher intramuscular fat content（P<0.05）,the content of pH1 and intramuscular fat in thigh muscle of female ducks in cage group was lower than that in cage group（P<0.05）.In general,net cage rearing can improve the production performance and some meat quality traits of meat ducks,and is suitable for feeding smallsized meat ducks.2.Correlation analysis of residual feed intake with growth performance,slaughter performance,meat quality and serum biochemical indexesTo investigate the relationship between RFI and growth performance,slaughter performance,meat quality and serum biochemical indexes of small-sized meat ducks.A total of 1000 healthy 21-day-old ducks were randomly selected for this experiment,and adopt single cage feeding mode on the net.During the experiment period（22～63 days）,all individuals were measured for growth performance.At 63 days of age,30 high RFI ducks（HRFI）and 30 low RFI ducks（LRFI）（half male and half female）were selected for blood sampling and slaughter test to determine slaughter performance,meat quality and serum biochemical indexes.The results showed,in terms of growth performance,RFI,FCR and ADFI in LRFI group were significantly lower than those in HRFI group（P<0.05）,but there were no significant differences in body weight at 22 days of age（BW22）,BW63 and ADG（P>0.05）.In terms of slaughter performance,there were no significant differences in all slaughter traits between LRFI and HRFI groups（P>0.05）.In terms of meat quality,the shear force of breast muscle in LRFI group was lower than that in HRFI group（P<0.05）,and there were no significant differences in other meat quality traits between the two groups（P>0.05）.In terms of serum biochemical indexes,the triglyceride（TG）and glucose（GLU）in LRFI group were lower than those in HRFI group（P<0.05）.In addition,insulin（INS）in LRFI group was higher than that in HRFI group（P<0.05）.Correlation analysis showed that RFI was highly positively correlated with FCR and ADFI in growth performance（P<0.01）,almost no correlation with body weight traits（P>0.05）.RFI was negatively correlated with breast muscle percentage and lean meat percentage（P<0.05）,only had a significant negative correlation with breast muscle percentage of female ducks（P<0.05）.RFI was positively correlated with breast muscle shear force（P<0.05）.In serum biochemical indices,RFI was significantly correlated with TG and GLU（P<0.05）.The results showed that LRFI could improve feed efficiency of small-sized meat ducks without affecting production performance.In conclusion,net cage rearing is more suitable for feeding small-sized meat ducks than flat rearing,and can improve feed utilization rate of individuals with LRFI without affecting production performance and meat quality,which is of great significance for breeding smallsized meat ducks with balanced quality and efficiency.