Inclusion of Sub-Antarctic Macroalgae (Gigartina Skosttsbergii) As Feed Ingredient for Grazing Sheep

Abstract

Macroalgae have been incorporated into livestock diets as novel protein and carbohydrate sources with bioactive compounds that could benefit both human and animal health. Recent studies demonstrated that macroalgae can reduce methane production in ruminants without affecting performance, supporting their use as a promising feed ingredient. In this study, we first evaluated the in vitro gas kinetic and methane emission of Gigartina skosttsbergii (red macroalgae), and secondly, we used in vivo assessment to obtain the effects of dietary Gigartina skottsbergii (Gs) supplementation for grazing sheep on growth performance and blood parameters. Our results showed that the dietary inclusion of Gs (at 450 g DM/d) for sheep did not alter body weight, average daily gain, and most of the blood parameters. The implementation of Gs mitigated enteric methane (CH4) emission, in vitro, at this inclusion rate; however, this was accompanied by lower in vitro gas production (IVGP) and in vitro dry matter degradability (IVDMD). Further research is needed to refine the potential impacts of Gs on ruminal fermentation, methane emission, and product quality.