Effects Of Forsythia Suspense Extract On Alleviating Growth Iihibition And Oxidative Injury In Broilers Induced By Different Stimuli

This study was performed to determine the effects of Forsythia swpensa extract (FSE) supplementation on performance, antioxidative status and meat quality in broiler chickens induced by different stimuli.Expt.1 was conducted to determine the effects of FSE on performance, nutrient digestibility, antioxidant enzymes activities, serum metabolites and immune parameters for broilers treated with corticosterone (CS). The broilers were randomly allotted to 1 of 4 treatments (6 replicates per group,6 broilers) in a 2 x 2 factorial arrangement that included FSE supplementation (0 or 100 mg/kg) and CS administration (0 or 20 mg/kg of diet for 7 consecutive days starting on d 14). Corticosterone administration decreased{P< 0.01) average daily gain (ADG) and impaired (P< 0.01) feed conversion ratio from d 22 to 42 and d 1 to 42, which were alleviated (P< 0.05) by dietary FSE supplementation. CS administration caused decreases (P< 0.01) in the apparent digestibility of energy, relative weight of bursa and thymus, serum superoxide dismutase (SOD) activity and serum antibody titers to Newcastle disease virus (NDV), however, all of these changes were attenuated (P< 0.05) by dietary FSE supplementation. Meanwhile, CS administration caused increases (P< 0.01) in serum malondialdehyde (MDA) and uric acid, however, FSE supplementation demonstrated the inhibition (P< 0.05) of serum uric acid (d 21) and MDA (d 42).Expt.2 was conducted to determine the effects of FSE on performance, antioxidative status and meat quality of breast muscle for broilers treated with dexamethasone (DEX). The broilers were randomly allotted to 1 of 4 treatments (6 replicates per group,6 broilers) in a 2 x 2 factorial arrangement that included FSE supplementation (0 or 100 mg/kg) and DEX injection (s.c.) (saline or 2 mg/kg body weight DEX for 6 consecutive days starting on d 42). DEX injection decreased (P< 0.01) average daily gain and feed conversion ratio from d 42 to 48, increased (P< 0.01) serum uric acid concentration, however, all of these changes were attenuated (P< 0.01) by dietary FSE supplementation. DEX injection caused decreases (P< 0.01) in total antioxidant capacity, glutathione peroxidase activity and DPPH radical scavenging activity of breast muscle, and subsequently resulted in increase (P< 0.01) in protein carbonyl and malondialdehyde contents, however, all of these changes were attenuated (P< 0.05) by dietary FSE supplementation. DEX injection increased (P< 0.01) pH decline, L* and b* values, and drip loss of breast muscle, decreased (P< 0.01) polyunsaturated fatty acids (PUFA) content and the ratio of PUFA and saturated fatty acids, however, all of these changes were attenuated (P< 0.05) by dietary FSE supplementation.Expt.3 was conducted to determine the effects of FSE on antioxidative status and meat quality of breast muscle for broilers treated with 3-h transport. The broilers were randomly allotted to 1 of 4 treatments (6 replicates per group,6 broilers) in a 2×2 factorial arrangement that included FSE supplementation (0 or 100 mg/kg) and transport treatment (stayed in cage or 3-h transport starting on d 42). Broilers were killed after 3-h transport to obtain muscle tissues and body weight was calculated for each cage. Transport stress increased (P< 0.01) body loss of transported broilers, which were alleviated (P< 0.05) by dietary FSE supplementation. Transport stress caused decrease (P< 0.05) in total antioxidant capacity, glutathione peroxidase activity and DPPH radical scavenging activity of breast muscle, and subsequently resulted in increase (P< 0.01) in malondialdehyde (MDA) contents, however, all of these changes were attenuated{P< 0.05) by dietary FSE supplementation. Dietary FSE did not alter the avian uncoupling protein (avUCP) mRNA expression, however, the upregulation of avUCP was insufficient to reduce muscle MDA contents and prevent muscle from transport-induced oxidative stress. Transport stress increased (P< 0.05) pH decline and b* values of breast muscle, decreased (P< 0.01) a* values, however, FSE supplementation demonstrated the inhibition (P< 0.05) of b* values.Expt.4 was conducted to determine the effects of FSE on antioxidative status and meat quality of breast muscle for broilers treated with corticosterone (CS). The broilers were randomly allotted to 1 of 4 treatments (6 replicates per group,6 broilers) in a 2* 2 factorial arrangement that included FSE supplementation (0 or 100 mg/kg) and CS injection (s.c.) (corn oil or 4 mg/kg body weight CS starting on d 42). Broilers were killed after 3-h injection to obtain muscle tissues and body weight was calculated for each cage. CS injection increased (P< 0.01) body loss and serum uric acid concentration, however, all of these changes were attenuated (P< 0.01) by dietary FSE supplementation. CS injection caused decreases (P< 0.01) in total antioxidant capacity, superoxide dismutase, glutathione peroxidase activity and DPPH radical scavenging activity of breast muscle, and subsequently resulted in increase (P< 0.01) in protein carbonyl and malondialdehyde contents, however, all of these changes were attenuated (P< 0.05) by dietary CS supplementation. CS injection increased (P< 0.01) L* and b* values, and drip loss of breast muscle, decreased (P< 0.01) a*, polyunsaturated fatty acids (PUFA) content and the ratio of PUFA and saturated fatty acids, however, all of these changes were attenuated (P< 0.05) by dietary FSE supplementation.hi conclusion, dietary FSE supplementation enhanced nutrient digestibility and performance of broiler possibly by reducing oxidative stress and immune depression challenged by CS; Pre-slaughter stress induced by DEX injection (s.c), transport and CS injection (s.c.) caused the increase of body loss and the decrease of meat quality, however, the supplementation of FSE alleviated body loss and the decrease of meat quality by increasing antioxidant and inhibiting protein catabolism.