Dietary methionine effects on IGF-I and GHR mRNA expression in broilers

Area of Science:

• Animal Science
• Molecular Biology
• Nutritional Biochemistry

Background:

• Methionine is an essential amino acid crucial for poultry growth and development.
• Understanding its impact on growth factors like IGF-I and GHR is vital for optimizing broiler production.
• Different methionine sources and levels may differentially affect gene expression and animal performance.

Purpose of the Study:

• To investigate the effects of varying methionine levels and sources on IGF-I and GHR gene expression in broiler liver and breast muscle.
• To correlate gene expression changes with overall broiler performance.
• To determine the optimal methionine strategy for broiler growth.

Main Methods:

• Broilers (22-42 days) were fed five diets: control, DL-methionine (DL1, DL2), and methionine hydroxy analogue-free acid (MHA-FA1, MHA-FA2) at different levels.
• Liver and breast muscle tissues were collected post-euthanasia for RNA extraction.
• Quantitative real-time PCR (qRT-PCR) was used to measure IGF-I and GHR gene expression.

Main Results:

• DL2 methionine supplementation resulted in the best overall broiler performance.
• IGF-I gene expression in the liver was significantly higher in broilers fed methionine compared to the control group.
• Liver IGF-I mRNA levels were highest in the DL2 group, and liver GHR gene expression was significantly increased by DL2 supplementation compared to the control.
• Methionine supplementation did not affect GHR and IGF-I gene expression in breast muscle tissue.

Conclusions:

• Methionine supplementation, especially at higher levels like DL2, enhances broiler performance.
• Dietary methionine positively influences IGF-I and GHR gene expression in the liver, suggesting a role in growth factor stimulation.
• Methionine's impact on growth-related gene expression is tissue-specific, with no significant effect observed in breast muscle.