Plasma lipoprotein concentration as an indicator of fatness in broilers: Effect of age and diet

1. The relationships between plasma very low density lipoprotein (VLDL) plus low density lipoprotein (LDL) triglyceride concentrations at 3 and 7 weeks of age and body fat content at 7 weeks were studied in male and female broiler grandparent stock fed on diets containing about 25 or 90 g fat/kg.

2. Plasma VLDL plus LDL triglyceride concentrations were similar in males and females and only slightly higher in birds fed on the high‐fat diet. Concentrations at 3 weeks were similar to those at 7 weeks.

3. Body fat content was correlated more closely with plasma VLDL plus LDL triglyceride measured at 7 weeks than at 3 weeks.

4. Phenotypic correlations between body fat content and plasma VLDL plus LDL triglyceride concentrations at 7 weeks were 0.47 and 0.43 for males and females respectively fed on the high‐fat diet and 0.70 and 0.60 for males and females fed on the low‐fat diet.

5. Phenotypic correlations between body fat content and measurements with an abdominal caliper were 0.35 and 0.49 in birds fed on the high‐ and low‐fat diets respectively.

6. A possible procedure for selecting for leanness in broiler breeding programmes on the basis of measurements of plasma VLDL plus LDL triglycerides is discussed.