The effect of quantitative feed restriction on allometric growth in broilers.

Area of Science:

• Animal Science
• Poultry Science
• Nutritional Physiology

Background:

• Feed restriction in broiler chickens is a common practice to manage metabolic disorders, improve feed efficiency, and influence carcass conformation.
• Understanding the impact of graded feed restriction levels during critical growth periods is essential for optimizing broiler production.

Purpose of the Study:

• To investigate the effects of modest, graded feed restriction during the second and third weeks of broiler life on growth performance and carcass characteristics.
• To analyze the allometric growth patterns of various body parts in response to feed restriction.
• To determine potential sex-specific responses to feed restriction protocols.

Main Methods:

• Broiler chickens were subjected to different levels of feed restriction (70-95% of ad libitum intake) during the second or third week of life.
• Growth performance parameters including body weight (BW), average daily gain (ADG), and feed conversion ratio (FCR) were monitored.
• Weekly dissections were performed to assess the allometric growth of breast muscle, legs, abdominal fat pad, liver, gastro-intestinal tract (GIT), and heart.

Main Results:

• Feeding 70% of ad libitum intake in week 2 and 80% in week 3 reduced ADG and BW during restriction, but compensatory growth was observed post-restriction.
• No significant differences in final BW, FCR, or major organ weights were noted at 35 days, except for altered allometric growth curves for breast muscle.
• Feed restriction in week 2 (70% ad libitum) showed potential for fat pad reduction, while restriction in week 3 (80-85% ad libitum) negatively impacted breast muscle allometric growth.

Conclusions:

• Modest feed restriction can influence broiler growth dynamics and body composition, with timing being a critical factor.
• Early feed restriction (week 2) may offer benefits for fat reduction, whereas later restriction (week 3) could compromise breast muscle development.
• Sex-specific differences in allometric growth were observed, suggesting that feed restriction strategies may need to consider sex-based variations.