Nutritional Value Of Duck Grease And Its Effects On Growth Perfomance,Carcass Characteristics And Meat Quality Of Growing-finishing Pigs

To explore the effect of duck grease (DKG) on growing-finishing pigs, two experiments were conducted to investigate the nutritive value and effects of duck grease on growth performance, carcass characteristics and meat quality. The results could provide theoretical support for using duck grease in livestock farming.Exp.l Evaluation of nutritive value of duck greaseThis experiment was conducted to evaluate nutritive value of DKG, and to determine the apparent digestible and metabolizable energy of DKG in pigs. A total of 16 DLY barrows with a mean body weight of 39.68 kg were randomly allotted to two dietary treatments with eight replicates each. Pigs were fed individually. The control diet was a corn-soybean meal without DKG, and another treatment diet was basal diet with 4% DKG. The formal digestive and metabolic trial lasted for 4 days.The result indicated that the calculated apparent digestible and metabolizable energy of the DKG by replacement method were 35.75 MJ/kg and 34.43 MJ/kg respectively.Exp.2 Effects of duck grease on growth performance, carcass characteristics and meat quality of growing-finishing pigsA total of 72 pigs (72 barrows; Duroc x Landrace x York; 31.62±2.31kg initial BW) were used in an 82-d study to evaluate the effects of DKG compared to soybean oil (SBO) in corn-soybean-meal-based diet on growth performance, carcass characteristics and meat quality. There were six replicates (pens) per testament and six pigs (barrows) per pen. The study was divided into 2 periods of growing stage and finishing stage with DKG or SBO being included at 2% and 1% respectively.The results showed as follows.1. No significant difference was observed for growth performance and carcass characteristics.2. The inclusion of DKG in growing-finishing pig diets significantly improved apparent digestibility of GE and DM (P< 0.05).3. Pigs fed DKG had higher intramuscular fat (IMF) content (P<0.05) and lower shear force (P<0.05) in longissimus muscle(LM), and tended to increase muscle fiber density in LM (P=0.063).4. Pigs fed DKG had lower (P< 0.05) serum TC、TG and LDL-cholesterol concentrations in finishing stage (P=0.051).5. The inclusion of DKG in pig diets significantly increased C18:0 (P<0.05) content, and decreased C18:2 content and the ratio of PUFA to SFA (P<0.05) in LM compared with SBO.6. Adding DKG increased the level of LPLmRNA in hepatic tissue (P< 0.05), and tended to decrease the level of HSLmRNA in LM (P=0.082) and the level of H-FABPmRNA in backfat (P=0.051).Our data suggested that adding DKG had no negative impact on growth performance and carcass characteristics, but improved the meat tenderness and IMF content, and regulated gene expressions.In conclusion, the calculated apparent digestible and metabolizable energy of DKG were 35.75 MJ/kg and 34.43 MJ/kg respectively. Repalcement of SBO for DKG at 2%(in growing stage) or 1%(in finishing stage) in corn-soybean meal pig diet had no significant effect on growth performance and carcass characteristics, but could improve the meat tenderness and influence the fatty acid compositions in LM, the mechanism of which was associated with the regulation of lipid metabolism and related genes expression.