The effects of feed-borne Fusarium mycotoxins on the performance and health of rainbow trout (Oncorhynchus mykiss)
This thesis is an examination of the effects of low levels of naturally occurring 'Fusarium' mycotoxins, predominately deoxynivalenol, on the performance and health of rainbow trout. Fish performance parameters including weight gain, growth rate, feed efficiency and nutrient utilization efficiency responded linearly or quadratically to low levels of deoxynivalenol ranging from 0.3 (control) to 2.6 ppm. Additionally, significant differences in growth rate, feed efficiency and carcass crude protein content between fish fed the diet containing 2.6 ppm and fish pair-fed the control diet were observed, suggesting that reduction of feed intake is not the sole mechanism of action of deoxynivalenol in rainbow trout. No significant differences in the apparent digestibility of crude protein and gross energy of fish fed diets containing 0.3 (control) to 2.0 ppm deoxynivalenol were determined. However, histological examination indicated morphological changes of the livers of some fish fed diets containing 2.6 ppm DON.