RESUMEN
A feeding trial was conducted to evaluate the effects of increasing alfalfa leaf levels on the performance of organic broilers. The impact of drying temperature on the nutritional value of alfalfa leaves and thereby on broiler performance was studied using alfalfa leaves dried at either low (alfalfa leaves low temperature (ALLT)) or high temperatures (alfalfa leaves (AL)). Six hundred male Hubbard JA-757 broilers were divided into five feeding groups (Control (C), AL2, AL3, AL4 and ALLT5). Alfalfa leaf content was increased in each of the three fattening phases by 5% (C: 0%-0%-0%; AL2: 0%-5%-10%; AL3: 5%-10%-15%; AL4: 10%-15%-20%; and ALLT5: 10%-15%-20%). At the end of the experiment, broilers in group C had the highest body and carcass weights. Groups AL3, AL4 and ALLT5 showed the lowest body and carcass weights. In particular, the early introduction of alfalfa leaves (5% in phase 1) and high alfalfa leaf content (15%-20%) significantly decreased performance. Antinutritional substances such as saponins occur in alfalfa. In fact, the saponin analysis showed high contents of 3-Glc-Glc-28-Ara-Rha-medicagenic acid and HexA-dHex-Pen-Pen-Pen-zanhic acid in both high- and low-temperature alfalfa leaves.