Mycotoxin concentration in salt-treated wet brewers’ grains and effects of their substitution for soybean meal and corn silage

ABSTRACT This study investigated the occurrence of mycotoxins in wet brewers’ grains (WBG) treated with salt (sodium chloride) and the intake, nutrient digestibility, and nitrogen use efficiency in lamb diets. Two experiments were conducted: first, WBG was distributed in plastic boxes and treated with no additive (control), sodium formate (3 g/kg of WBG), or three levels of salt—25, 30, and 35 g/kg of WBG. The WBG were stored at room temperature (17.7±4.6 ℃) for 27 days. In the second experiment, eight six-month-old male lambs were allotted to one of four total mixed ration (TMR) diets in a 4 × 4 double Latin square: 0, 10, 20, and 30% of WBG replacing corn silage and soybean meal. In the first experiment, the concentration of mycotoxins throughout the experiment was lower than the tolerance levels accepted by the European Community and Food and Drug Administration for animal feedstuffs. However, the control and sodium formate groups showed visual fungal development on the WBG surface from the sixth day and presented an unpleasant smell from day 12. In the salt treatments, fungal growth was observed on top of the WBG from day 12 and an unpleasant smell from day 15. Salt-treated WBG showed a lower pH than the control and sodium formate groups and decreased dry matter deterioration. In the second experiment, including up to 30% WBG in the TMR did not affect dry matter, organic matter, neutral detergent fiber, and acid detergent fiber intake or digestibility in lambs. However, the N digestibility and N use efficiency increased with WBG inclusion. These results suggest that salt can be used to increase the storage time of WBG up to 15 days and the inclusion of up to 30% WBG in TMR for lambs can improve N use efficiency without negatively affecting nutrient intake and digestibility.