Slaughterhouse by-products preserved by Lactobacillus plantarum fermentation as feed for mink and foxes

Abstract

Lactic acid fermentation was evaluated as a method to preserve abattoir waste for use in fur animal diets. The method used involved grinding, acidifying to pH 5–5.2 by formic acid and propionic acid, addition of 6% molasses as a carbohydrate source and a starter culture of Lactobacillus plantarum. Fermentation was completed after 2–3 days at 25°C. The final pH of the fermented product was 3.8–4.1. Storage experiments revealed satisfactory stability. The fermented products could be kept for weeks at room temperature (20°C) and for months in a cold room (4°C). The amino acid composition of the 4 types of abattoir waste tested was not significantly changed by fermentation. Digestibility studies with mink revealed slight, but significant ( P < 0.05), effects of fermentation. The digestibility of cystine and threonine was reduced and that of glycine and proline increased. Two types of fermented abattoir waste were investigated in 2 long-term feeding experiments with mink and blue foxes. In the mink trial, diets with 10 or 20% fermented abattoir waste supported normal reproduction, kit mortality and body growth. In one experiment, there was a significant reduction in mink kit body weights with 20%, but not with 10% fermented abattoir waste in the diet. In the fox trial, litter sizes and kit viability tended to improve with 20% fermented abattoir waste, while kit body weights were unaffected. It is concluded that fermentation could be an acceptable process for the preservation of abattoir waste intended for the feeding of fur animals.