Appétence et valeur alimentaire de foins de fétuque indemnes ou infestés par le champignon endophyte Acremonium coenophialum

Abstract

This paper aims to clarify the potential effect of the endophytic fungus, Acremonium coenophialum, on the feeding value of tall fescue hay under climatic conditions and usual management in France. Two batches of hay were harvested from two fields sown with seeds of the same variety either totally infested (E+) or free (E-) of endophyte. Presence of the endophyte had no effect on the chemical composition or in vitro digestibility in hay nor on the dry matter in situ degradation kinetic assessed following the nylon bag procedure. In vivo digestibility of both hays, assessed on sheep in individual crates, was quite similar (E+: 57.0%; E-: 57.9%). However, the E- hay was clearly preferred by sheep during the palatability test (53.1 vs 15.7% rate of consumption) and was more ingested (54.7 vs 50.1 g/kg animal metabolic weight). The results showed, therefore, that the endophyte can induce some negative effects on palatability and volontary intake of tall fescue but without altering the potential digestibility of infested hay. Regarding further investigations on the effect of infested grass forages on animal productions, it appears that emphasis should be on the level of toxicity rather than on feeding value.