Effects of Different Grains on Nutrient Digestibility, Blood Glucose Metabolism, and Fecal VFA Content in Weaned Foals

Abstract

Abstract Background Intensive farming practices have gradually shifted from traditional grazing to housing for horses in China, changing from a single forage diet to a more comprehensive mixed diet. Grains as the primary source of energy for horses under intensive farming conditions, play a critical role in their growth, development, and health. However, there is a considerable variation in glucose production based on the different sources of dietary grains and starch content, proportions, and structures. Thus, it is crucial to choose a suitable grain as a source of energy for horses at various stages of growth.The study aimed to investigate the effects of different diets of steam-pressed flaked grains (corn, oats, and barley) on nutrient digestibility, blood glucose metabolism, and fecal volatile fatty acids (VFA) content in weaned foals of Kazakh horses. Male Kazakh horse foals (n = 18) weaned at the age of 5 months were randomly divided into three groups (n = 6 each) based on the different grains in the diet: corn group (CG), oats group (OG), and barley group (BG). The amount of concentrate supplement fed to the foals was determined based on the presence of equal starch in the concentrate. The results showed that the apparent digestibility of all nutrients was lower in the OG than in the CG and BG. The amylose intake and digestibility were higher in the OG than in CG. Blood glucose concentration and glucagon levels were higher in the CG than in OG and BG. The insulin/glucose ratio was higher in the BG than in the CG and OG; BG increased the fecal lactic acid and total VFA (TVFA) levels in foals and reduced the fecal pH, respectively. Results The results showed that the amylose intake and digestibility were higher in the OG than in CG. Blood glucose concentration and glucagon levels were higher in the CG than in OG and BG. The insulin/glucose ratio was higher in the BG than in the CG and OG; BG increased the fecal lactic acid and total VFA (TVFA) levels in foals and reduced the fecal pH, respectively. Conclusions In this study, Feeding corn increases the blood glucose concentration in weaned foals, is efficient in sugar production and promotes glucagon secretion in foals; Oats and barley increased the digestibility of amylose in feed significantly. Feeding barley improves blood insulin sensitivity in foals and can increase the concentration of lactic acid in faeces. By comparing the digestive physiology of three grains in weaned foals, choosing the best grains for weaning foals and scientifically formulating the diet of weaning foals could improve the digestion and absorption of nutrients, promoting growth and development.