Plasma growth hormone levels in normal and testosterone implanted growing turkeys

Area of Science:

• Animal Science
• Endocrinology
• Poultry Science

Background:

• Testosterone influences growth and development in various species.
• Growth hormone (GH) plays a critical role in regulating body weight and growth rate.
• Understanding the interplay between hormones and growth is crucial for poultry production.

Purpose of the Study:

• To investigate the effect of testosterone implantation on the growth of female turkeys.
• To measure peripheral plasma concentrations of immunoreactive growth hormone (GH) in relation to growth.
• To determine the correlation between growth, age, and GH levels in treated and control turkeys.

Main Methods:

• Tracking the growth of normal and testosterone-treated female turkeys from 2 to 16 weeks of age.
• Measuring peripheral plasma concentrations of immunoreactive growth hormone (GH).
• Analyzing the correlation between body weight, age, weekly weight gain percentage, and plasma GH levels.

Main Results:

• Testosterone-treated turkeys exhibited increased body size compared to controls between 3 and 11 weeks of age.
• Plasma GH levels showed an inverse correlation with bird age and body weight across both groups.
• GH concentrations in testosterone-treated birds were higher at 4 weeks but lower at several other time points (3, 6-9 weeks) compared to controls, with no consistent association between weight gain and GH differences.

Conclusions:

• Testosterone administration impacts turkey growth, but its effect on growth hormone levels is complex and time-dependent.
• Plasma GH levels are a significant indicator of growth rate and body weight in turkeys.
• Further research is needed to elucidate the precise mechanisms linking testosterone, GH, and growth in poultry.