Nutritional values and antioxidative activities of whole peanuts and peanut skins for ruminant feeds

This study was conducted to investigate the nutritive values of two peanut by‐products, nonstandardized whole peanuts and peanut skins, along with their effects on microbial growth and fermentation in the rumen, their roughage values, and their antioxidative activities by a digestion trial using four goats. The experimental rations were alfalfa haycube (basal ration), 85% alfalfa with 15% whole peanuts, and 70% alfalfa with 15% whole peanuts and 15% peanut skins. The ether extracts and crude protein in whole peanuts were 47% and 27% on a dry matter basis (DM) both with over 90% of digestibilities, resulting in total digestive nutrients (TDN) of 140%. Peanut skins also had a high energy value with 91% of TDN. Ruminal concentrations of total volatile fatty acids (VFA) and acetic acid decreased in the rations containing the peanut by‐products, but the NDF digestibility and ruminal microbial protein estimated from urinary purines was not altered by feeding the peanut by‐products. Plasma oxidative stress maker, malondialdehyde, tended to be lower when peanut skins were supplemented. Whole peanuts and peanut skins could be used as high‐energy and high‐protein diets for ruminants, and peanut skins would be expected as a feed having antioxidant functions.