الفهرس 
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Abstract
Biochemical alterations in lipid pattern in laying hens feed on some lipotropic factors added to rations were investigated.This study investigated the effects of supplementary dietary some lipotropic factors as (Choline, DL-Methionine and L-Carnitine) on biochemical alterations of
serum lipids and lipoproteins metabolism in laying hens.
The study was conducted with eighty 36 weeks old Lohman brown hens. According to the type of lipotropic factors supplemented to the basal ration the birds were divided into four main groups, each one consisting of 20 laying hens placed in separated rooms and classified as follows:
Group I: (control group), comprised 20 laying hens , they were fed on a basal diet only, used as control for all experimental groups.
Group II: ( Choline supplemented group) included 20 laying hens, they were fed on a basal diet supplemented with Choline, where Choline was added as double amount to the basal ration (1500mg/kg. ration).
Group III: (DL-Methionine supplemented group) contained 20 laying hens, they were fed on a basal diet supplemented with DL- Methionine, where Methionine was added as double amount to the basal ration
(550mg/bird daily).
Group IV: (L-Carnitine supplemented group) consisted of 20 laying hens, they were fed on a basal diet supplemented with L-Carnitine, where L-Carnitine was added to the basal ration at the concentration of (500mg/kg). The experiments lasted for 12 weeks, during which the hens had constant access to both water and the diets.
Random blood samples were collected six times, from each group,
at biweekly intervals, from the onset of lipotropic factors supplemented to the basal ration.
Blood samples for serum separation were obtained from the wing vein from all groups (control and experimental groups).The clean, clear serum was separated then kept in a deep freeze at —20°C until used for
subsequent biochemical analysis. All sera were analysed for the following parameters:
1-Total lipids.
2-Total cholesterol.
3-Triacylglycerols .
4-Phospholipids.
5-Non esterified fatty acids (NEFA).
6-High -density lipoprotein cholesterol (HDL-Cholesterol).
7-Low- density lipoprotein cholesterol (LDL-Cholesterol ).
8-Very low-density lipoprotein cholesterol(VLDL-Cholesterol). 9-Serum Lipase activity.
The obtained results summarize the following:
1- Serum total lipids:
A very highly significant increase in serum total lipids concentration was observed in choline supplemented group after 2 weeks of the experiment. This increase became non significant after 6 and 10 weeks and highly significant after 12 weeks of supplementation of the diet.
However, the value of serum total lipids showed a non significant decrease after 4 weeks. This decrease became very highly significant after 8 weeks of dietary choline supplementation.
Serum total lipids concentration in methionine supplemented group showed a very highly significant increase after 2 and 4 weeks of the experiment. This increase became significant after 6 weeks and non significant after 10 and 12 weeks of supplementation. However, a very highly significant decrease in serum total lipids concentration was observed after S weeks of supplementation of the diet.
Serum total lipids concentration in the L-carnitine supplemented group showed a very highly significant increase after two weeks of the experiment. This increase became non significant after 4 weeks and significant after 12 weeks of supplementation. However, L- carnitine supplementation caused _ a very highly significant decrease in serum total lipids concentration after 6 weeks of the experiment. This decrease became non significant after 8 weeks and significant after 10 weeks of carnitine supplementation in comparison with the control group.
2- Serum total cholesterol:
Serum total cholesterol concentration in the choline supplemented group was very highly significant increase after 2, 6, 8 and 12 weeks of the experiment. However, after 4 weeks of supplementation the value of serum total cholesterol concentration showed a very highly significant decrease. This decreas became highly significant after 10 weeks than that in the control. Experimental results indicated that, supplementary methionine increased serum total cholesterol concentration very highly significant after 2, 4 and 6 weeks of the experiment. However, after 8 weeks post-supplementation the value of serum total cholesterol concentration showed a non significant decrease. This decrease became very highly significant after 10 weeks and highly significant after 12 weeks in comparison with the control group.
serum total cholesterol concentration in the L-carnitine
supplemented group was very highly significant increase after 2 and 8 weeks of the experiment. This increase became non significant after 4 and 12 weeks of supplementation. However, L- carnitine supplementation caused a highly significant decrease in serum total cholesterol concentration after 6 and 10 weeks of the experiment.
3- Serum triacylglycerols:
Serum triacylglycerols concentration in the choline supplemented group was very highly significant increase after 2, 6, 10 and 12 weeks of the experiment. This increase was not significant after 8 weeks of supplementation of the diet, however, after 8 weeks of supplementation the value of serum triacylglycerols concentration showed a very highly significant decrease than that in the control.
Laying hens given diets supplemented with methionine showed a very highly increase in serum triacylglycerols concentration after 2, 4 and 10 weeks of the experiment. This increase became non significant after 6 weeks. However, after 8 and 12 weeks post- supplementation with methionine the value of serum triacylglycerols concentration showed a very highly significant decrease when compared with the control group.
Supplementary L-carnitine increased serum triacylglycerols concentration very highly significant after 2 weeks of the experiment. However, L- carnitine supplementation caused a highly significant decrease in serum triacylglycerols concentration after 4 weeks of the experiment. This decrease became very highly significant after 6, 10 and 12 weeks and non significant after 8 weeks of supplementation of the diet in comparison with the control group.
4- Serum phospholipids:
Supplemental choline caused a very highly significant increase in serum phospholipids concentration after 2 weeks of the experiment. This increase was not significant after 4 weeks of supplementation. A significant decrease in serum phospholipids concentration was observed after 8 weeks of supplementation, however, choline supplementation caused a non significant decrease in the value of serum phospholipids concentration after 6 , 10 and 12 weeks of the experiment in comparison with control group.
Serum phospholipids concentration in laying hens given diets supplemented with methionine showed a very highly increase after 2 and 4 weeks of the experiment. However, after 6 weeks post-supplementation with methionine the value of serum phospholipids concentration revealed a very highly significant decrease. This decrease became non significant after 8 , 10 and 12 weeks of study.
Supplemental L-carnitine increased serum phospholipids..
concentration very highly significant after 2 weeks of the experiment. This increase became non significant after 4, 8 and 10 weeks of supplementation of the diet. However, L- carnitine supplementation caused a non significant decrease in serum phospholipids concentration after 6 weeks, this decrease became highly significant after 12 weeks of the experiment in comparison with the control group.
5- Serum non-esterified fatty acids(NEFA):
Supplemental choline caused a significant decrease in serum nonesterified fatty acids (NEFA) concentration after 2 and 6 weeks of the experiment. This decrease was very highly significant after 4, 8 and 10 weeks of supplementation. Moreover, a non significant decrease in serum NEFA concentration was observed after 12 weeks of supplementation in comparison with control group.
Serum nonesterified fatty acids concentration in laying hens given diets supplemented with methionine showed a highly significant decrease during the first 2, 4 and 6 weeks of the experiment. This decrease became very highly significant after 8 and 10 weeks of study. However, after 12 weeks post- supplementation with methionine the value of serum NEFA concentration revealed significant decrease when compared with the control group.
A highly significant decrease in serum NEFA concentration was observed after 2, 6 and 10 weeks of the experiment in L-carnitine Supplemented group. This decrease became significant after 4 weeks . However, L- carnitine supplementation caused a very highly significant decrease after 8 weeks, this decrease became non significant after 12 weeks of the experiment in comparison with the control group.
6-Serum high-density lipoprotein cholesterol (HDL-
cholesterol):
A non significant increase in serum HDL-cholesterol concentration was observed in laying hens given diets supplemented with choline after 2 and 12 weeks of the experiment. This increase became significant after 4 and 8 weeks and very highly significant after 6 weeks of supplementation of the diet. However, serum HDL-cholesterol level showed a non significant increase after 12 weeks of the experiment.
Serum HDL-cholesterol concentration in the methionine supplemented group showed a non significant decrease after 2 weeks of the study. This decrease became significant after 8 and 10 weeks of supplementation. On the other hand, the value of serum HDL-cholesterol concentration revealed no significant change after 4 weeks of the experiment. However, after 6 weeks the value of serum HDL-cholesterol concentration showed a highly significant increase this increase became significant after 12 weeks post- supplementation.
Serum HDL-cholesterol concentration in the L-carnitine supplemented group was significantly decrease after 2 weeks of study. This decrease became highly significant after 10 weeks and non significant after 4, 8 and 12 weeks of supplementation. However, L-carnitine supplementation caused a significant increase in serum HDL-
cholesterol concentration after 6 weeks of the experiment than in the control.
7-Serum low-density lipoprotein cholesterol(LDL-
cholesterol):
Choline supplementation did not significantly affect the value of serum LDL-cholesterol concentration in laying hens after 2 weeks of the experiment. However, after 4 weeks the value of serum LDL-cholesterol concentration showed a non significant increase. This increase became highly significant after 6 and 12 weeks and very highly significant after 8 and 10 weeks of supplementation of the diet.
A very highly significant decrease in serum LDL-cholesterol concentration was observed in the methionine supplemented group after 2 weeks of the study.This decrease became non significant after 6 weeks of supplementation. However, methionine supplementation caused a very highly significant increase in the value of serum LDL-cholesterol concentration after 4 and 10 weeks of the experiment. This increase became non significant after 8 weeks of supplementation.
Serum LDL-cholesterol concentration in the L-carnitine supplemented group showed a significant decrease after 10 weeks of study. This decrease was very highly significant after 2, 6 and 12 weeks of supplementation. However, L- carnitine supplementation caused a significant increase in serum LDL-cholesterol concentration after 4 weeks of the experiment. This increase was non significant after 8 weeks of supplementation of the diet in comparison with the control group.
8- Serum very low-density lipoprotein cholesterol (VLDL-
cholesterol):
A very highly significant increase in serum VLDL-cholesterol concentration in the choline supplemented group was observed after 2, 6, 10 and 12 weeks of experiment. This increase became non significant after 4 weeks of study. However, choline supplementation caused a very highly significant decrease in serum VLDL-cholesterol concentration after 8 weeks of supplementation of the diet when compared with the control group.
Serum VLDL-cholesterol concentration in the methionine supplemented group showed a very highly significant increase after 2, 4 and 10 weeks of the study.This increase became non significant after 6 weeks of supplementation. However, methionine supplementation caused a very highly significant decrease in the value of serum VLDL-cholesterol concentration after 8 and 12 weeks of the experiment.
Serum VLDL-cholesterol concentration in the L-carnitine supplemented group was very highly significantly increase than in the control after 2 weeks of the study. However, L- carnitine supplementation caused a highly significant decrease in serum VLDL-cholesterol concentration after 4 weeks of the experiment.This decrease became very highly significant after 6, 10 and 12 weeks and non significant after 8 weeks of supplementation of the diet in comparison with the control group.
9- Serum lipase:
A highly significant increase in serum Lipase activity in the choline supplemented group was observed after 2, 4 and 12 weeks of experiment. This increase became very highly significant 8 and 10 weeks of study. However, choline supplementation caused a significant decrease in serum Lipase activity after 6 weeks of supplementation when compared with the control group.
Serum lipase activity in the methionine supplemented group showed a significant increase after 2 and 12 weeks of the study.This increase became non significant after 10 weeks of supplementation. However, methionine supplementation caused a very highly significant increase of serum Lipase activity after 4 weeks and highly significant after 8 weeks of the experiment. On the other hand, serum lipase activity revealed no significant change after 6 weeks in comparison with the control group.
Serum lipase activity in the L-carnitine supplemented group showed a non significant increase after 2, 10 and 12 weeks of the study. This increase became significant after8 weeks. However, L- carnitine supplementation caused a non significant decrease in serum Lipase activity after 4 weeks of the experiment. This decrease became very highly significant after 6 weeks of supplementation in comparison with the control group.