Assessing in vivo digestibility and effects on immune system of sheep fed alfalfa hay supplemented with a fixed amount of Ulva rigida and Gracilaria vermiculophylla - Cabrita, A.R.J.; Correia, A.; Rodrigues, A.R.; Cortez, P.P.; Vilanova, M.; Fonseca, A.J.M. (Journal of Applied Phycology, 2017)