Effect of feeding and feed deprivation on plasma concentrations of prolactin, insulin, growth hormone, and metabolites in horses.

This research on horses investigates how different types of feeds and complete deprivation of feed influence the concentrations of certain hormones and metabolites in the animals’ blood, showing that particular types of eating activities, rather than feed properties, might stimulate prolactin secretion and that feed deprivation had limited impact on the prolactin response to a meal.

Objective of the Research

• The main objective of the experiment was to evaluate the effects of various types of feeds and total feed deprivation on the plasma concentrations of hormones like prolactin, insulin, and growth hormones, as well as some metabolites in horses.

Experimental Design and Methodology

• The research was divided into two separate experiments. The first experiment involved six different feeding conditions for stallions, ranging from no feed to different types of pellet feed, cracked corn, and chopped alfalfa with the inclusion or exclusion of water. The second experiment involved totally depriving mares of feed for three days.

Findings from Experiment 1

• Experiment 1 showed that the horses’ prolactin response to feeding was similar across different types of food and wasn’t influenced by what was in the feed itself.
• The insulin response was highest in horses that were fed with pelleted feed supplemented with water.

Findings from Experiment 2

• In the second experiment, it was found feeding the mares after keeping them deprived for three days increased the plasma levels of prolactin, insulin, and glucose similarly in all of them.
• The mares subjected to feed deprivation showed a positive growth hormone response after feeding, which was not seen in non-deprived mares.
• The prolactin response to thyrotropin-releasing hormone was greater in the feed deprived mares as compared to the controls.

Conclusion

• Based on the results of these experiments, the authors concluded that prolactin secretion in horses may be stimulated more by the act of eating than by the nutritional content of the feed itself. They also determined that total feed deprivation does not significantly impact the subsequent prolactin response to a meal.