The Optiml Nutrients Level Of Digestible Energy And Lysine In Feed For Landrace×New Qingping Commercial Hogs

Two experiments were conducted to study the effect of dietary lysine and degestible energy level on growth performance, carcass traits and meat quality of Landrace×New Qingping commercial hogs, aiming at determining the optimum lysine and degestible energy level in feed and offer some useful data for nutrients regulating pork quality.60 healthy Landrace×New Qingping hybrid piglets(36.24±0.75kg) were randomly assigned into 1 of 4 groups with three replicates of five pigs. The feeding progress was divided into two stages, the growing period(80-120d) and the finishing period(120-170d). Experiment diets was formulated according to NRC(1998). There was two degestible energy levels (80-120d:13.4MJ/kg,14.0 MJ/kg; 120-170d:13.18 MJ/kg, 13.81 MJ/kg) and two lysine levels(80-120d:0.64 g/MJ,0.60 g/MJ; 120-170d:0.58 g/MJ,0.53 g/MJ) in each stage.2×2 factorial arrangement was adopted in this experiment. The experiment diet was formulated based on corn, soybeanmeal, rapeseed meal and wheat bran. After the final weighing, one pig per pen whose weight was close to the average was picked and slaughtered for carcass(carcass weight, carcass length, average backfat thickness, loin eye area, lean yield) and pork quality (marbling score, meat colour, pH, drip loss, water holding capacity, intramuscular fat, etc.) measurement.The main results were as follows:(1)During the growing stage,compared with the 13.4 MJ/kg group,14.0 MJ/kg group ADFI was significantly decreased by 11.27%(P=0.052).In the finishing stage, compared with the 13.18MJ/kg group,13.81 MJ/kg group ADFI was significantly decreased by 18.26%(P<0.05).DE significantly affacted ADFI of whole stage. ADFI of high energy group(growing stage:14.0 MJ/kg;finishing stage:13.81MJ/kg) was much lower than low energy group(growing stage:13.4 MJ/kg;finishing stage:13.18MJ/kg) by 16.24%.During the growing, finishing and whole stage, lysine and DE didn't affact ADG of each group.Among the four groups, the group(DE:13.4 MJ/kg;Lys:0.64 g/MJ) had the greatest ADG.On F:G, the group(finishing stage:14.0 MJ/kg) was 13.48%lower than the group(finishing:13.4 MJ/kg) (P<0.01).During the whole stage, the high energy group(growing stage:14.0 MJ/kg;finishing stage:13.4 MJ/kg) was 9.86%lower than low energy group(P< 0.01). (2)Average backfat thickness of High lysine:energy group was lower than low lysine:energy group(P=0.200).The low energy and high lys group had the highest lean percentage(P> 0.05).Lysine:energy and DE didn't affact other carcass traits such as loin eye area(P> 0.05).(3) For meat quality traits, compared with the low energy group, improving dietary digestible energy could significantly increase muscle pH (P<0.05). Water holding capacity of high-energy group was significantly higher in the low-energy group (P<0.01). Intramuscular fat and marbling score were not significantly affected by dietary digestible energy levels (P> 0.05).In experiment 2, experiment design was the same as experiment 1.48 healthy Landrace×New Qingping hybrid piglets were randomly assigned to 1 of 4 dietary treatments groups with three replicates of four pigs according to initial weight(34.86±1.01kg). The feeding progress was divided into two stages, the growing period(90-130d) and the finishing period(130-170d).The dietary treatment was same as experiment 1.The main results were as follows:During the finishing period, ADFI of high-energy group was significantly higher than low-energy group(P<0.05).Digestible energy and lysine:DE didn't affact ADG and F:G of each group during growing, finishing and whole stage.During the growing stage, the group(DE:13.4 MJ/kg;Lys:0.64 g/MJ) had the greatest ADG.From the results all above, the conclusions are as follows:(1) Conffering the results of experiment 1 and experiment 2, if ADG and carcass lean percentage was taken into account, the optimal DE and Lys level was 13.4 MJ/kg and 0.64 g/MJ for the growing stage,13.18MJ/kg and 0.58g/MJ for the finishing stage, because DE and Lys did not affact ADG and carcass lean percentage of each stage.(2) In this experiment, diet with high energy concentration can improve muscle water holding capacity and pork quality.