Efecto de la fertilización en las variaciones fitoquímicas y su repercusión antinutricional en cuatro variedades de morera Effect of fertilization on the phytochemical variations and its antinutritional influence on four mulberry varieties

The effect of organic fertilization from poultry dung on the quantitative variations of the main secondary metabolites present in four Morus alba Linn. varieties was studied. The total concentrations of polyphenols (FT), flavonoids (Flav), coumarins (Cum), steroidal saponins (Sap) and primary carbohydrates and pseudosugars (CHS), were quantified. Through the Main Components Analysis a high variability was detected in the first three components (82,35%). The Automatic Classification Analysis separated the treatments in four groups with distinctive characteristics. The doses of 100 and 300 kg N/ha/year caused, independently, homogeneous variations in the phytochemical pattern of the four varieties; while with the application of 500 kg N/ha/year the variety Acorazonada was quantitatively differentiated from the rest. From the hierarchical point of view, the positive contribution to group formation increased as the fertilizer doses applied were higher. The results allow to conclude, integrally, that the increasing amounts of organic manure progressively decreased the quantitative performance of the secondary metabolites (FT, Cum and Sap) present in the varieties and increased the concentrations of beneficial compounds (Flav). The four mulberry varieties fertilized with poultry dung showed excellent nutritive quality for being used intensively to feed ruminants and monogastric animals.