Effects of protein levels in the diets of layers on the egg production rate and the chemical composition of poultry eggs in the tropics

Four hundred and fifty layers of the White Leghorn and White Rock breeds were used to study the effects of graded levels of dietary proteins on the chemical composition and egg production rate of layers in the tropics. The dietary protein levels employed were 12.0, 14.0, 16.0, 18.0 and 20.0%, and the trial lasted 6 months. The results obtained showed that hen‐day production percentages increased up to the 16.0% protein diet and then declined. Feed consumed per dozen eggs also declined up to the 16% protein diet and then increased slightly. All the layers except those on the 18% protein diet lost weight to varying degrees, the birds on the 12% protein diet losing most. There were significant decreases in the percentages of eggs weighing less than 40 g and those weighing between 40 and 49.0 g, and significant increases in the percentages of eggs weighing between 50 and 59.0 g and 60 g and above, as the dietary protein levels increased. Both the total moisture and crude protein percentages were significantly increased as the dietary protein levels increased but the differences in total ash, shell and total lipid percentages were not significant and were remarkably constant.