| This study was aimed to investigate the effect of different composited oils on growth performance, nutrient utilization, digestive enzyme activity, meat quality and lipid metabolism in Arbor Acre (AA) broilers. The object of this study was to approach the mechanism that composited oils may possibly improve on carcass traits of broilers.648one-day-old AA chicks were selected and randomly divided into6groups with6replicates of18chickens each (9males and9females). The feeding trial consisted of two periods (0-3weeks and4-6weeks of age). The dietary treatments were as follows:corn-soybean meal control (CON), positive control (SO, corn-soybean based diet with soybean oil), negative control (LO, corn-soybean based diet with lard oil), the rest three treatments were diets with composited oil based on palm oil (COP), on coconut oil (COC), and on many vegetable oils (COV), respectively. The research included four experiments.Experiment1was conducted to determine the effects of different composited oils on growth and slaughter performance and relative weight of organs in broilers. The results showed that:(1) In the starter period, the COP, COC and COV had a higher (P<0.05) ADG compared to CON, COP was also higher than LO (P<0.05), ADFI of COP was increased compared to CON and SO (P<0.01). COC was higher (P<0.05) than SO, the FCR of COP was lower than CON and LO (P<0.05); in the grower period, the ADG, FCR of each groups were not affected significantly (P>0.05), the ADFI of LO and COP was higher (P<0.05) than LO, COC and COV; From the whole period, the ADG of LO and COP was higher than CON (P<0.05). the ADFI of LO was higher (P<0.05) than LO and COV, the FCR of COP and COC was lower than LO (P<0.05).(2) There were no significant differences of the slaughter performance in all treatments during the six weeks.(3) The organ index of liver of SO was higher than LO and COP (P<0.05) in21d and COV was higher than LO (P<0.05); the heart index of heart of LO was lower than SO, COP and COC (P<0.05); the organ indexes of pancreas, spleen, thymus and bursa of Fabricius in all treatments were not affected significantly (P>0.05). There were no significant differences of the organ indexes of liver, heart, spleen, pancreas, thymus and bursa of Fabricius among all treatments in42d (P>0.05).Experiment2was conducted to determine the effects of different composited oils on the nutrient utilization and the digestive enzyme activity in broilers. The results were follows:(1) Compared to CON, other groups tended to improve the nutrient digestibility (P>0.05) in42d, the digestibility of Ca was increased (P<0.05) in SO, COP and COC. COP and COC was also higher than LO and COV (P<0.05), SO and COC improved (P<0.05) the digestibility of P compared to CON, COP and COV (P<0.05).(2) The trend of increased lipases, amylase and trypsin were observed in each group compared with CON in both21d and42d of broilers, but not significantly (P>0.05).Experiment3was conducted to determine the effects of different composited oils on the body fat distribution and meat quality in broilers. The results indicated that:(1) There were no significant differences of the abdominal fat pad, subcutaneous and inter-muscular adipose tissue, percentage of breast and thigh muscle fat in all treatments in42d (P>0.05).(2) The drip loss (24h) in breast muscle of COP was higher than SO, LO, COC and COV (P<0.05), then drip loss (48h) of breast muscle of SO was lower than other treatments (P<0.05), the drip loss (24h) of thigh muscle of LO was lower than CON and SO (P<0.05); the cooking loss of COC was lower than other treatments (P<0.05). The shearing force of SO was significantly lower than CON (P<0.05).(3) In terms of fatty acid composition of breast muscle, the content of palmitic acid (C16:0) in CON was significantly higher than SO and LO, the content of trans-oleic acid (C18:1) in LO was higher than COC (P<0.05), and the content of cis-oleic acid in CON was higher than SO (P<0.05), the content of cis-linoleic (C18:2) and linolenic acid (C18:3) in all oil-supplemented treatments were higher than CON (P<0.05), and the content of linolenic acid in SO was higher than LO and COP (P<0.05), from the whole fatty acid composition of breast muscle, the SFA of CON, COC, COV was higher than LO (P<0.05), the MUFA of LO was higher than other treatments (P<0.05), and the PUFA of all oil-supplemented treatments was higher than CON (P<0.05); the value of U/S in LO was higher than CON, SO, COC, COV (P<0.05); higher n-3PUFA was obtained in SO than CON, LO, COP, COV (P<0.05), and LO, COP, COC also had higher n-3PUFA than CON (P<0.05); SO, LO, COP, COC received a higher n-6PUFA than CON (P<0.05); for the value of n-6/n-3, SO, LO, COP, COC were higher than CON (P<0.05).(4) The content of cholesterol of breast muscle in SO was lower than other groups except LO (P<0.05).Experiment4was conducted to determine the effects of different composited oils on serum lipoprotein profiles and activity of lipid metabolic enzymes in broilers. These findings suggest that:(1) At21days, the serum concentration of TC in COP and COC were lower than CON and LO (P<0.05), SO, LO and COV were lower than CON (P<0.05); the serum concentration of LDL-C both in SO and COP were lower than CON and LO (P<0.01), COC, and COV were significantly lower than CON and LO (P<0.05); The value of HDL-C/LDL-C in serum of SO was higher than other groups (P<0.01) and than COP (P<0.05), COP was higher than CON and LO (P<0.01) and than COC and COV (P<0.05), COV was higher than CON and LO (P<0.05). At42d, the serum concentration of TC in SO and COP were lower than COV (P<0.05); the serum concentration of LDL-C in COP was lower than LO (P<0.01) and than CON (P<0.05), COV was lower than LO (P<0.05); The value of HDL-C/LDL-C in serum of COP was higher than LO, COC, COV (P<0.01) and than CON (P<0.05), SO was higher than other groups (P<0.05) except COP (P<0.05).(2) No significant differences were observed in the activity of serum LPL and HL (P>0.05), but the activity of total lipase in SO was improved (P<0.05). In the liver, the activity of LPL in COP, COC and COV was higher than CON and LO (P<0.01); the activity of HL in all composited oil groups than other groups (P<0.05); the activity of total lipase in COC was higher than CON, SO and LO (P<0.01), COP was higher than CON and LO (P<0.01) and than SO (P<0.05), COV was higher than CON (P<0.01) and than SO and LO (P<0.05).In conclusion, COP. COC and COV all can improve the growth performance of broilers, and COP is better; all groups which add oil have the tendency to improve nutrient utilization of broilers, COP and COC could promote the digestibility of P and Ca; all groups which add oil increase the PUFA in breast muscle of broilers, SO balance the ratio of fatty acid, and then lower the cholesterol levels, and COC followed; COP and COV can both regulating lipid metabolism by lower the concentration of LDL-C... |
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