Effects of feeding drunken horse grass infected with Epichloë gansuensis endophyte on animal performance, clinical symptoms and physiological parameters in sheep.

ABSTRACT

BACKGROUND: Many reports showed that grass-endophyte symbiosis induced livestock poisoned. Yet, there is no study evaluating clinical symptoms and physiological parameters in sheep fed Epichloë gansuensis endophyte-infected grass. The objective of the present study was to investigate these indexes by feeding sheep with endophyte-infected A. inebrians (E+ Group) or endophyte-free A. inebrians (E- Group) drunken horse grass or alfalfa hay (Control Group). RESULTS: The Epichloë endophyte caused obvious toxicity symptoms in the sheep fed E+ A. inebrians, with 1 of the 5 sheep having died by the 35th day. The feed intake and body weight gain of the E+ Group were significantly less than the E- and control groups (P < 0.05). Serum concentrations of alanine aminotransferase (ALT, 45.5 mmol/L) and aspartate aminotransferase for the E+ group (AST, 139.3 mmol/L) were significantly (P < 0.05) greater than for the E- (ALT, 31.2 mmol/L; AST, 78.6 mmol/L) and control (ALT, 32.6 mmol/L; AST, 56.6 mmol/L) groups at the fifth week; serum concentration of creatinine for the E+ group (63.8 mmol/L) was also significantly (P < 0.05) greater than for E- (56.6 mmol/L) and control groups (58.5 mmol/L). Meanwhile, urine biochemical indices for the E+ group indicated that ketone and occult blood were significantly (P < 0.05) elevated compared to the other groups while urine pH values were significantly (P < 0.05) acidic. The relative weight of heart, brain, liver, lung and kidney for Group E+ were almost two fold more than the other groups, but uterus weight was about half that found for Group E- or Control. CONCLUSIONS: We conclude that the Epichloë endophyte infection is the cause of A. inebrians toxicity to sheep. Interestingly, none of the measured parameters differed significantly between E- and the control groups, which implied that drunken horse grass could be utilized efficiently by sheep when not infected by the Epichloë endophyte.