Formic acid–sodium benzoate preserved slaughterhouse offal and supplementary folic acid in mink diet

Abstract Slaughterhouse offal from beef slaughtering was preserved with 16 g kg −1 formic acid and 3 g kg −1 sodium benzoate and used in mink feed throughout the production year. The ensiled offal replaced 0, 0.5 or 1.0 parts of the frozen stored slaughterhouse offal in the basal diet, the level of which was 300, 200 and 260 g kg −1 during growth-furring, breeding and lactation periods respectively. Because folic acid has a central role in formate metabolism and in all tissues of high rate of cellular division during the breeding and lactation periods, each diet group was further divided into two levels of supplemented dietary folic acid, 1.3 or 10 mg kg −1 DM. Weaning weights of male kits and lactating females, as well as early post-weaning growth and hemoglobin development were negatively affected by the highest silage level, providing 4.5 g formic acid kg −1 feed. The pelt quality of the groups that received silage was comparable to or even better ( p