Prolonged, moderate nutrient restriction in beef cattle results in persistently elevated circulating ghrelin...

Area of Science:

• Animal Science
• Endocrinology
• Nutritional Physiology

Background:

• Ghrelin, a hormone primarily involved in appetite regulation, plays a role in energy homeostasis.
• Understanding ghrelin's response to nutrient restriction is crucial for managing cattle health and productivity.

Purpose of the Study:

• To investigate the impact of prolonged, moderate nutrient restriction on plasma ghrelin concentrations in steers.
• To determine the relationship between plasma ghrelin and key hormones, metabolites, and rumen fermentation products.

Main Methods:

• Four ruminally cannulated steers were subjected to a crossover design with two dietary intake levels: 240% (2.4xM) and 80% (0.8xM) of body weight maintenance.
• Blood samples were collected serially to measure ghrelin, growth hormone (GH), non-esterified fatty acids (NEFA), insulin, and glucose.
• Rumen fluid was analyzed for pH and volatile fatty acids (VFA).
• Stepwise regression analysis was used to assess correlations.

Main Results:

• Plasma ghrelin concentrations were significantly elevated (P < 0.001) in steers fed the 0.8xM diet throughout the 21-day treatment period.
• Steers on the 0.8xM diet exhibited increased plasma GH and NEFA, and decreased insulin concentrations (P < 0.001), indicative of a catabolic state.
• Plasma ghrelin fluctuations showed only a weak correlation with hormones, metabolites, and rumen fermentation end products.

Conclusions:

• Prolonged, moderate nutrient restriction in cattle leads to elevated plasma ghrelin concentrations and a catabolic physiological state.
• The relationship between plasma ghrelin and indicators of nutritional status or rumen fermentation is weak, suggesting other regulatory factors may be involved.