Effects Of Stress On Blood Parameters, Meat Quality And Hsps MRNA Transcript Levels In Pekin Ducks

Animal protection and animal welfare are valued by more and more countries, especially EU countries, in the formulation and implementation of agricultural policy, the welfare of animals must be fully taken into account. As one of the important indicators of evaluation of animal welfare, stress has become a hot topic of animal welfare workers. With the occurrence of H7N9, live bird markets were closed, and every concentrated slaughter has become inevitable, however, the distance from the farm to the slaughterhouse ranged from a few kilometers to a few tens of kilometers, in the process of transportation, the heat that generated in the process of movement, the shaking and deceleration of the vehicle, the lack of food and water and the noise around the slaughterhouse can adverse negative effect on ducks. To explore whether noise and transport stress could produce adverse impacts on its production performance and behavior, this paper respectively discussed the noise stress, simulated transport stress, anti-stress additives, Ve and rest before slaughter for every blood stress index and internal Hsps gene expression and meat quality.Experiment ⅠIn order to investigate the effect of noise stress on the blood biochemical indicators and meat quality of Pekin ducks, sixty Peking ducks (42days old) were randomly divided into three groups, each treatment had five replicates and each replicate had four ducks. Group I was the control group. Group Ⅱ was exposured at80db. Group Ⅲ was exposured at100db. Noise stimuli of both80db and100db intensities were continued20min. After the stress indicators were measured. The results showed that:the T3and T4levels of the group Ⅱ and group Ⅲ were significantly lower than the control group (P<0.01). The ALT, CK, AST, and GSH-Px levels of the ducks of100db noise group increased, and the differences between group Ⅲ and the control group were significant (P<0.01or P<0.05). Besides the protein content and pH of the Chest muscle decreased significantly (P<0.01) after noise stress. The MDA and Protein carbonyl contents of group Ⅱ and group Ⅲ were significantly higher than the control group (P<0.01). In addition, after noise stress the hsp70mRNA and hsp90mRNA transcription levels of liver, spleen, lung and kidney were significantly higher than the control group (P<0.01). And the stronger the noise decibel, the higher the transcription levels would be. These datas showed that the acute noise stress would affect the blood parameters and muscle quality of Pekin Ducks and we recommended that the noise around the slaughterhouse should be reduced in order to avoid an impact on the quality of duck.Experiment ⅡIn order to explore whether Ve could reduce the effects of noise stress on meat quality and blood biochemical indexes of Pekin ducks. Sixty Pekin ducks (2weeks old) which together with experiment Ⅰ were randomly divided into three groups, each treatment had five replicates and each replicate had four ducks. Trial period lasted28days. Group Ⅰ was the control group. Group II was exposured at100db. Group Ⅲ was exposured at100db and VE was added in the diet. After the stress indicators were measured. The results showed that:the T3and T4levels of the group Ⅲ were significantly higher than group Ⅱ (P<0.01). The CK, AST and GSH-Px levels of group Ⅲ were significantly lower than group Ⅱ (P<0.01or P<0.05). Besides the pH of the chest muscle of group Ⅲ were significantly higher than group Ⅱ (P<0.01). The MDA and Protein carbonyl contents of group Ⅲ were significantly lower than group Ⅱ (P<0.01). The results of qRT-PCR showed that the hsp70mRNA and hsp90mRNA transcription levels of liver, spleen, lung and kidney in group III were significantly lower than group Ⅱ (P<0.01). These datas showed that VE can effectively alleviate the negative influence of noise stress.Experiment ⅢTo explore the effect of transportation stress on meat quality and blood biochemical indicators of Pekin ducks. According to the level of Jiangsu province highway transportation speed, ducks were packed in the car which ran at the speed of40-60km/h to transportation stress. Group Ⅰ was the control group. Group Ⅱ transported1h before slaughter. Group Ⅲ transported2h before slaughter. Group IV transported3h before slaughter. After the stress indicators were measured. After2h transportation, the T3, T4and INS levels were significantly decreased (P<0.01); while the ALT, AST, CK and GSH-Px levels significantly increased (P<0.01). In terms of meat quality, the protein carbonyl, MDA contents of group Ⅲ increased significantly (P<0.01), while the muscle protein, fat contents and pH decreased significantly (P<0.01). The transcription levels of hsp70mRNA gradually increased with increasing transport time, while the transcription levels of hsp90mRNA first increased, then decreased and reached a maximum at2h transportation. These results indicated that a2-h transport caused serious stress in ducks and we recommended that slaughterhouse should be built within60km from the farms.Experiment ⅣTo explore whether extendding the time to rest before slaughter could reduce the impact of transport stress on meat quality and blood biochemical indicators of Pekin ducks, Sixty Pekin ducks (42days old) which together with experiment Ⅰ were randomly divided into four groups. Group Ⅰ:immediately slaughtered without transport; group Ⅱ:transported for2h before slaughter; group Ⅲ:transported for2h and rested for30min before slaughter; group Ⅳ transported for2h and rested for2h before slaughter. After the stress indicators were measured. The results showed that:the T3, T4and INS levels of group Ⅳ were significantly higher than group Ⅱ (P<0.01), and the differences between group Ⅳ and group Ⅰ were not significant (P>0.05).The ALT、AST、CK and GSH-Px levels of group Ⅳ were significantly lower than group Ⅱ (P<0.01).The MDA and Protein carbonyl contents of group Ⅳ were significantly lower than group Ⅱ (P<0.01); and the pH of of group IV were significantly higher than group Ⅱ(P<0.01); In addition, the hsp70mRNA and hsp90mRNA transcription levels of liver, spleen, lung and kidney in group Ⅳ were significantly lower than group Ⅱ (P<0.01). Therefore we recommended that ducks experienced transport stress should be considered to rest a period of time before slaughter to reduce the impact of transport stress on meat quality and blood biochemical indicators of Pekin ducks and the advisable time is2h.