| In order to study the effects of different energy restriction levels and different restriction methods on growth performance,bone parameters,digestive enzymes activity and m RNA expression of related genes in broilers,the following two trials were designed:Trial 1 Effects of Different Energy Restriction levels on growth performance and Digestive EnzymeActivity and expression of Related Gene in Sanhuang ChickensA total of 72 female Sanhuang broiler chickens aged 15 days were randomly divided into three groups: the control group,the 15% energy restriction group(15% ER group)and the 30% energy restriction group(30% ER group),24 birds of each group,each bird was housed in one cage.The birds were slaughtered at 30-day-old,44-day-old and 65-day-old.To study the effects of different energy restriction on growth performance,visceral index,abdominal fat ratio,skeletal parameters,digestive enzymes activity and related m RNA expression of Sanhuang chickens.(1)The results of growth performance showed: After 15 d of energy restriction,the final weight(FW),average daily gain(ADG)and total feed intake(TFI)of the 15% ER group and the 30% ER group were significantly lower than the control group(P<0.05),and these indicators of 30% ER group were significantly lower than the 15% ER group(P<0.05);After 14 d of compensatory growth,the FW of the 30% ER group was significantly lower than the 15% ER group and the control group(P<0.05),and the ADG and F/G of 30% ER group were significantly lower than the control group(P<0.05);After 35 d of compensatory growth,there was no significant difference among the three groups(P>0.05).(2)The results of visceral index and abdominal fat ratio showed: At 30-day-old,the pancreas index of the control group was significantly lower than the energy restriction groups(P<0.05);At44-day-old,the heart index of the control group was higher than the energy restriction groups and there was a significant difference with 15% ER group(P<0.05).At 65-day-old,there were no significant differences of heart index,liver index,pancreas index,gizzard index and abdominal fat ratio among three groups(P>0.05).(3)The results of digestive enzymes activity showed: In pancreas,the activity of trypsin of 30%ER group was significant higher than the control group(P<0.05)after feed restriction for 15 days;At44-day-old,there were no significant differences among three groups of the activity digestive enzymes.At 65-day-old,the activity of digestive enzymes in the control group was higher than the energy restriction groups and there were significant differences in amylase and lipase(P<0.05).In foregut,theactivity of trypsin of the control group was significantly higher the 30% ER group(P<0.05)for limited breeding to 30 d;After two weeks compensatory growth,there were no significant differences among three groups of three kinds of enzyme activity;At 65-day-old,the activity of amylase of the 30% ER group was significantly higher than the control group(P<0.05);the activity of lipase in two ER groups were significantly lower than the control group(P<0.05);the activity of trypsin in 30% ER group was higher than others and there was a significant difference with 15% ER group.(4)The results of skeletal parameters showed: After 15 days feed restriction,the length of tibia of15% ER group was significantly higher than the 30% ER group(P<0.05);the tibia diameter of the control group was significantly higher than others(P<0.05).There was no significant difference of the data after two weeks compensatory growth.After 35 days compensatory growth,the tibia diameter of the control group was significantly higher than others(P<0.05);the femur diameter of the control group was significantly higher than the two ER groups and the significant difference was only exist between 15% ER group and the control group(P<0.05).(5)The results of gene expression showed: Each group of three kinds of enzyme gene m RNA relative expression had no significant difference.At 44-day-old,the m RNA relative expression of amylase gene of the 30% ER group was significantly higher than other two groups(P<0.05).At65-day-old,the m RNA relative expression of amylase gene of the 30% ER group was significantly lower than other two groups(P<0.05);the m RNA expression of lipase and trypsin of the Ad group were higher significantly than other restricted groups(P<0.05).Tria 2 Effects of Different Restriction Methods on growth performance and Digestive EnzymeActivity and expression of Related Gene in AA ChickensThe 84 female AA broiler chickens at 8 day-old were fed in Test 2,the birds were randomly assigned to 4 treatment groups: ad libitum group(Ad group),quantitive restriction group(QR group),energy restriction group(ER group)and Protein restriction group(PR group),21 birds of each group.Each bird was fed in one cage.The birds were sacrificed at 21-day-old and 42-day-old.To study the effects of different restriction methods on growth performance,visceral index,abdominal fat ratio,skeletal parameters,digestive enzymes activity and related m RNA expression of AA chickens.(1)The results of growth performance showed: After 14 days feed restriction,the FW and the ADG of the QR group and the ER group were significantly lower the Ad group(P<0.05).Besides,there was also a significant difference between the QR group and the ER group in the FW and the ADG(P<0.05);the TFI of the QR group was significantly lower than other three groups(P<0.05);The F/G of the QR group and the ER group was significantly lower than the PR group and the Ad group(P<0.05).In CG stage of 42 d,the FW of the three restricted groups were no significantly differencewith the Ad group.There was a difference between the QR group and the ER group in the FW(P<0.05).(2)The results of visceral index and abdominal fat ratio showed: After 14 days feed restriction,the heart index of the QR group and the ER group was significantly lower than the PR group(P<0.05);In the aspect of abdominal fat ratio,the PR group was higher than other three groups and there was a significant difference with the Ad group and the ER group(P<0.05).At 42 d,there was only a significant difference between the PR group and the ER group in liver index(P<0.05).(3)The results of digestive enzymes activity showed: In pancreas,the activity of amylase of the QR group was higher than other three groups and it was significantly difference with the Ad group and the PR group(P<0.05);the activity of trypsin of the ER group was significantly lower than the Ad group and the PR group(P<0.05).At 42 d,the activity of lipase of the PR group was higher than other groups and it was significantly difference with the Ad group(P<0.05);In the aspect of the activity of trypsin,the ER group and the Ad group were significantly higher than other two groups(P<0.05).In foregut,the data of the CG stage showed that the activities of lipase and trypsin of the Ad group were significantly higher than other three restricted groups(P<0.05);In addition,the activity of the lipase of the QR group and the ER group were lowest,and there was a significantly difference between the QR group,the ER group and the PR group(P<0.05).(4)The results of skeletal parameters showed: Restricted to 21 d,the weight of tibia of the Ad group was significantly higher than the QR group(P<0.05);the length of tibia of the Ad group was significantly higher than other three restricted groups(P<0.05),the QR group was lower than others and it showed significant difference with the PR group and the ER group(P<0.05);In the aspect of tibia diameter,the PR group was higher than other restricted groups and there was a significant difference with QR group(P<0.05);the femur weight of QR group was significantly lower than other three groups(P<0.05)and its length was also lower than others and there was a significant difference with the Ad group and the ER group(P<0.05).In the aspect of femur diameter,the data of the Ad group and the PR group were higher than others.At 42 d,the femur weight of all restricted groups were lower than the Ad group(P<0.05)and other data showed no significant difference(P>0.05).(5)The results of gene expression showed: Restricted to 21 d,the m RNA relative expression of amylase of the QR group showed a rising trend compared to the Ad group,while other restricted groups lower than the Ad group.At 42 d,the m RNA expression of lipase of the Ad group was lower than other restricted groups and there was significantly difference between the Ad group with the ER group and the PR group(P<0.05),the m RNA expression of the QR group was significantly lower than the PR group(P<0.05);the m RNA expression of trypsin of the ER group was significantly higher thanother three restricted groups(P<0.05);the m RNA expression of amylase showed no significant difference among all groups.The study shows that the feed restriction certainly improved the growth performance of broilers and digestive function,and QR can increase in broilers’ pancreas index.In the aspect of gene expression,the restriction on the expression of amylase,lipase and trypsin gene in broilers did not cause significant differences,and some significant differences occurred during the compensation period. |
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