Cholesterol and Lipid Levels in Broilers

The effect of sex and age on the changes in cholesterol and lipid levels in plasma of broiler chick´s blood fattened to high live weights was studied in this experiment. 200 broiler chicks (120 males) and 80 females) of hybrid combination ROSS I fattened on starter BR1 from one day old to 26 days and on BR2-IT from 27 days to 9 weeks for females  and to 16 weeks for males . 

10 males and 10 females were slaughtered, eviscerated and processed every week from (5 to 16) weeks for males and (5-9) weeks for females. The live weight of the chicks varied from 965 to 6300 g (5 - 16 weeks /males) and 880 -2900 (5-9 weeks/females) respectively. No significant differences in cholesterol and lipid levels were observed at 5-9 weeks of age. 

In male chicks, lipid in plasma decreased daily as age advanced by 0.02147, while cholesterol in plasma of females increased daily by 0.02817.

As liver weight increased, the lipids in plasma of male chicks decreased by 0.00024, while cholesterol in females plasma increased by 0.00046.

Lipids constitute a very important group of organic substances in plant and animal tissue, since lipids include fats, and other compounds that resemble each other in physical properties.

The lipids vary in blood like other constituents, and found as fats, fatty acids, phospholipids, cholesterol and cholesterol esters.Chotinski (1975) found that the physical form of diet has no effect on the content of total lipids, phospholipids, triglycerides or free fatty acids in the blood. Griffin et al. (1982) found that the phenotypic correlation between the total plasma triglycerides and fat content were 0.50, 0.37, and 0.39 for males and for females it was 0.33, the content of triglycerides in plasma VLDL plus LDL showed similar correlations with the fat content   Barza et.al, (1983) found that the plasma lipids were the lowest when the diet supplied 13.4 MJ. ME/Kg and with 5 lx ,and the highest at 12.14 MJ with 55 Lx.Ehinger et al. (1982) found that the serum indices were influenced mainly by age ,since significant differences were observed in broilers slaughtered at 35, 41  ,  47  ,or 53 days of age.

Patterson et, al (1984) found no significant effects on plasma triglycerides in female broilers on different lines and fed on different diets to 44 days of age.

In this experiment 230 broiler chicks, 200males and 130 females ofhybrid combination ROSS 208 were used.

Chicks were fattened separately according to their sex in pens on deep litter from one day old to 16 weeks for males and to 9 weeks for females. on BR1 Starter (mash -1day old to 26 days) with 86% dry matter, 11.58MJ ME n  and  from 27 days to the end of the experiment on  BR1-IT (1/2mash +1/2 granular ) with 1195MJ MEn.

At the end of the 5^th week and in every following week till the end of the experiment 5 samples of 10 males and 10 females were slaughtered, eviscerated and studied the level of cholesterol and lipids in the blood plasma.

 Method of estimation:

  1-Absorbent sample A

  2-Absorbent sample B

  3-

Total cholesterol content in plasma; X in g/l

The dynamics of cholesterol and lipid levels in the plasma of male and female chicks are shown in table (1).

In male chicks, the cholesterol and lipid levels showed gradually increasing or decreasing tendencies, since the lowest values of cholesterol and lipid plasma were 2.63 mg/100ml (35 days ) and 3.75 g/l (105 days) while the highest were 4.58 mg/100ml ( 105 days ) and 5.82 g/l (35 days ) for cholesterol and lipid ,respectively.

In female chicks, cholesterol in plasma showed a gradual increase from 2.58 mg/100ml (35 days) to 4.49 mg/ 100ml (49 days), then decreased gradually from 5.7 g/l (35 days) to 4.32 g/l (49 days), then increased to about 5.01 g/l (56-63 days).

These high values in the level of lipid in plasma at earlier periods of life may be due to the fact that at 35 days of age a part of the fat yolk is still in the stomach of the chicks.

Sex differences in cholesterol and lipid levels in plasma of male and female chicks and the t-test are shown in table (2)

Table (2): Effect of sex on the levels of cholesterol and lipid in plasma of Broiler chicks at 35-63 days of age.

No significant differences in cholesterol and lipid plasma were observes between male and female chicks at 35-63 days of age.

Similar observations were made by Ehinger et al (1982), Patterson et al (1984) and others.

The dependence of the cholesterol and lipid levels in plasma (Y) on the age and on the live weight of chicks was expressed by linear regressions and second degree parabolic equations as shown in the table (3)

Table (3): Dependence of cholesterol and lipid in plasma on age and live Weight of chicks-regression equations.

1-BARZA, E.-BALASECA, M.-CONSTANTIN.N.: Effect of light and dietary energy on blood lipids in meat chickens.Inst.Agro.Nicolae Balcesenic.26:29-33.1983.

2-CHOTINSTI, D.: Lipid status of poultry in relation to physical form of the feed. Zhivotov.dni Nauki 12:94-98, 1975

3-EHINGER, F.-SEEMANN, G.: The influence of feed, age and sex on the gr performance and the carcass quality of broilers from different strains.2.Fat content.Arch.Geflugelkde 46:177-188.1982.

4-GRIFFIN, H.D.-WHITEHEAD, G.G.-BROADBENT, L.A.: The relationship between plasma triglyceride concentration and fat content in male and Female broilers, a basis for selection, Brit.{Poult.Sci.23:154-23,1983.

5-PATTERSON, D.L.-FRIARS, G.W.: Genetic effects and relationship among carcass fat content of broiler chickens and plasma triglyceride levels and liver traits. Can.J.Anim.Sci.64:339-349.1984.

6-SCOGIN, V.-HARRIS.G.G._BENSON, J.: Effects of feeding programs during the growing period on body weight, semen production and certain blood serum components of broiler breeder cockerels.Poult.Sci.59:4571.1980owing