Nutrients content and microbiological quality of salad crops as feed ingredient for ruminant diets

This study evaluated the nutritional composition and microbiological quality coupled with electronic nose odour profile of selected salad crops (SC). Eighteen sample SC deriving from a plant producing salad crops have been collected during the summer season in two sites: at the production site (factory plant) and after transport and one-day storage (to mimic farm site). The samples were then analysed for pH, dry matter (DM), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), and lignin. Eight selected samples were analysed for the enumeration of Total Viable Count (TVC) (ISO 4833), Enterobacteriaceae (ISO 21528-1), Escherichia coli (ISO 16649-1), coagulasepositive Staphylococci (CPS) (ISO 6888), presumptive B. cereus and its spores (ISO 7932),sulphite reducing Clostridia (ISO 7937), Yeasts and Moulds (ISO 21527-1) and the presence in 25 g of Salmonella spp. (ISO 6579). Data obtained were analysed using IBM SPSS Statistics version 21 software (SPSS Inc.). Salad crops at the production site (factory plant) and after transport and one-day storage (to mimic farm site), have shown pH value of 6.0 and 6.4, respectively. For the same material nutrient composition was comparable to that of common fresh grass: the overall mean of CP content was 210 g/kg DM, while average NDF, ADF and ADL contents were 360, 238, and 74 g/kg DM respectively. The main difference between fresh grass and SC was for DM content, that was lower (5.8+-0.8 g·kg-1) in SC samples compared to literature grass values. Total Viable Count was limited and Salmonella was always absent. Salad crops has some potential as feed ingredient for ruminant’s diets, even though a full verification of their potential need further deep investigation. The present work has been done in the frame of Progetto di Grande Rilavenza IT-RS ‘Sustainable animal nutrition’ (SUN) funded the Ministero degli Affari Esteri e della Cooperazione Internazionale.