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The Effects of Dhea on Performance and Lipid Metabolism of the AA Laying Broiler Breeders

Author: JiChangJin
Tutor: ZhangYuanShu;MaHaiTian
School: Nanjing Agricultural College
Course: Basic Veterinary Science
Keywords: DHEA AA laying broiler breeders performance lipid metabolism
CLC: S831
Type: Master's thesis
Year: 2009
Downloads: 11
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Abstract

Dehydroepiandrosterone (DHEA) is synthesized primarily by the zona reticularis of adrenal cortex.It is a precursor of sex steroid hormone biosynthesis. DHEA has numerous biological effects, especially on the lipid metabolism. But the effects of DHEA on performance and lipid metabolism of laying broiler breeders have not been reported. This test was focus on performance and lipid metabolism of laying AA broiler breeders with DHEA. The purpose is to provide a theoretical evidence for the research on biological effects of DHEA.There are two parts in the experiment:1 Effects of DHEA on performance of the AA laying broiler breedersOne hundred 16-week-old female AA broiler breeders were randomly divided into four groups. They are control group(C group), low dosage group (L group), middle dosage group (M group) and high dosage group (H group). When the breeders got 34 weeks old, DHEA were added in the feed for 7 weeks at 0 mg/kg for group C, 25 mg/kg for group L,50 mg/kg for group M and 50 mg/kg for group H. The number of eggs in each laying broiler breeder was recorded every day and the eggs were weighed. On the 49th day of the experiment, after fasting 12 hours, all the breeders were killed. The livers, abdominal fat, left breast muscle and leg muscle of all the breeders were weighed. The content of uric acid (UA) and creatinine (Cr) in the blood of breeders were detected. The diameter and density of muscle fiber were detected by cryosections. The results showed that, compared with the control group, the laying rate was extremely significantly elevated in L group (P<0.01),while extremely significantly decreased in M and H groups; the relative weight of live and leg muscle were not affected in L and M groups(P> 0.05),while were significantly elevated in H group (P< 0.05); the percentage of abdominal fat and the relative weight of breast muscle were not affected in all DHEA treated groups (P> 0.05); the content of UA was extremely significantly elevated in L group (P< 0.01), not affected in M group (P> 0.05) and significantly elevated in H group (P< 0.05); the content of Cr was not affected in M and H groups (P> 0.05),while extremely significantly elevated in L group (P< 0.01); the diameter and density of breast muscle fiber were not affected in all DHEA treated groups (P> 0.05); the diameter of leg muscle fiber was not affected in L group (P>0.05), significantly lower in M group (P<0.05) and extremely significantly lower in H group (P< 0.01); the density of leg muscle fiber was not affected in L group (P> 0.05), significantly higher in M group (P< 0.05) and extremely significantly higher in H group (P< 0.01)2 Effects of DHEA on lipid metabolism of the AA laying broiler breedersOne hundred 16-week-old female AA broiler breeders were randomly divided into four groups. They are control group(C group), low dosage group (L group), middle dosage group (M group) and high dosage group (H group). When the breeders got 34 weeks old, DHEA were added in the feed for 7 weeks at 0 mg/kg for group C, 25 mg/kg for group L,50 mg/kg for group M and 50 mg/kg for group H. On the 49th day of the experiment, after fastingl2 hours, all the breeders were killed. The content of blood glucose(BG), total cholesterol (TC), triacylglycerol (TG), high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C),non-esterified fatty acid (NEFA) in the blood of breeders were detected. The content of triiodothyronine(T3), thyroxin(T4), glucagon, leptin and tumor necrosis factor-a(TNF-a) in the blood of breeders were detected by radioimmunoassay(RIA).The mRNA expression of acetyl CoA carboxylase(ACC), fatty acid synthase(FAS),carnitine palmitoyl transferase I (CPT-I) and hydroxy methylglutaryl-CoA reductase(HMGR) were analyzed by Real-time PCR. The results showed that, compared with the control group, the content of BG was not affected in L group (P> 0.05), significantly determined in M group (P< 0.05) and extremely significantly decreased in H group (P< 0.01); the content of HDL-C was not affected in L and H groups(P> 0.05), while was significantly elevated in M group(P< 0.05); the content of NEFA was extremely significantly decreased in L and H groups (P< 0.01), while not affected in M group (P< 0.01); the content of TC,TG and LDL-C were not affected in all DHEA treated groups (P> 0.05).the content of T3 and T4 were not affected in L and H groups (P> 0.05),while significantly elevated in M group (P < 0.05); the content of Leptin was not affected in L group (P> 0.05), extremely significantly elevated in M group (P< 0.01) and significantly elevated in H group (P< 0.05); the content of Glucagon and TNF-a were not affected in all DHEA treated groups(P> 0.05).The result of mRNA expression showed that, compared with the control group, the mRNA expression of ACC was significantly decreased in M group (P< 0.05); the mRNA expression of FAS was significantly decreased in H group (P<0.05); the mRNA expression of CPT-I was extremely significantly elevated in L and M groups (P< 0.01), while significantly elevated in H group (P < 0.05); the mRNA expression of HMGR was significantly decreased in all DHEA treated groups (P<0.05)

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