Larch sawdust as functional additive

The larch sawdust (Larix decidua L., Pinaceae) is rich in valuable physiologically active compounds and functional polymers: arabinogalactans [1], lignans (mainly secoisolariciresinol and lariciresinol) [2] flavonoids (mainly taxifolin and dihydrokaempferol) [3] and diterpenes (larixyl acetate and larixol) [4]. Arabinogalactans, abundant in the genus Larix, are an excellent source of water-soluble prebiotic fibre and in monogastric animals increase beneficial gut anaerobes [5]. Moreover, larch sawdust extracts have been suggested to enhance immune function as shown in an ex-vivo study on ovine neutrophils [6]. We investigated whether larch sawdust (by Jannach Lärchenholz GmbH) supplemented to dairy cows have effects on blood biochemical parameters. The treated group received 250 g/d of Larch sawdust (n=10) and the control group 250g/d of placebo (n=10), mixed with 1 kg of a total mixed diet, for 14 d. Several biochemical changes induced by the supplementation of larch sawdust were observed. Biomarkers of liver function were influenced by the treatment. Total bilirubin was significantly lower in larch-treated animals (- 17%; P < 0.05). Cholesterol was lower in animals given the larch diet. VLDL, which are involved in lipid transport from the liver, were also slightly increased. A lower urea concentration was found in the larch-treated group (5.6 vs 6.5 mmol/L; P < 0.01). Total protein decreased significantly in animals given the larch diet, mainly due to a decrease in globulin concentration (from 35.1 to 33.5 g/L; P < 0.01). Because total globulin concentration can provide an indication of an animal’s humoral immune status or response, the observed effect could be beneficial in animal diet during challenges such as weaning, as well as in disease states. These results confirm previous studies and indicate that larch sawdust can be a resource as an appreciable feed additive. Moreover, larch sawdust is a waste product from the wood industry and would represent an economic additive. To confirm a valuable application, we have started further studies with other animal species.