## 1 Introduction  
The importance of alternatives in livestock feed is multifaceted, addressing economic, environmental, and sustainability concerns. Rising commercial feed costs and competition between human and animal grain consumption necessitate the exploration of alternative feed sources to reduce production costs and increase farmers' profitability [1; 2]. On the contrary, there is a need for the introduction of innovative additives in animal nutrition that can enhance animal health, growth, and productivity while addressing environmental and ethical concerns [3]. Feed additives can be classified into various categories, including metabolic modifiers, antibiotics, growth promoters, enzymes, probiotics, prebiotics, and minerals. These additives serve multiple purposes, such as enhancing nutrient utilization, controlling pathogens, stimulating immune responses, and improving digestibility [4]. In this context, among all the possible resources, seaweed plays a significant role [5; 6]. Seaweeds have emerged as a promising component in livestock feed due to their nutritional benefits and potential to mitigate environmental impacts. Historically, various types of seaweeds have been incorporated into the diets of livestock such as ruminants, pigs, horses, and poultry, with practices varying by region [7]. The nutritional profile of seaweeds, which includes essential amino acids, minerals, polyunsaturated fatty acids, antioxidants, and pigments, contributes to the health, growth, and performance of animals, making them a valuable addition to animal feed [8]. Additionally, the antioxidant properties of seaweeds can improve animal health and meat quality by enhancing the redox status and immune response, although overconsumption, particularly of brown seaweeds, should be avoided due to a high iodine content [9]. The cost of seaweed production and the need for sustainable harvesting practices are significant challenges that must be addressed to make seaweed-based feeds viable on a larger scale [10]. Across the different algal species, _Fucus vesiculus_, commonly known as bladderwrack, is a brown macroalga with significant ecological, pharmaceutical, and industrial applications. It thrives in temperate rocky shores and exhibits substantial seasonal variations in its ecophysiology, influenced by factors such as temperature and macronutrient availability, which affect its photosynthetic efficiency and elemental composition [11]. This seaweed is rich in bioactive compounds, including phlorotannins, peptides, fucoxanthin, and fucoidans, which contribute to its health-promoting effects [12; 13]. One of the primary functional properties of _F. vesiculuss_ is its potential to modulate lipid metabolism and reduce hyperlipidemia. Studies have shown that extracts rich in phlorotannins from _F. vesiculuss_ can significantly lower serum cholesterol, triglycerides, and free fatty acids while increasing high-density lipoprotein cholesterol (HDL-C) levels in animal models [14]. These findings suggest that _F. vesiculuss_ could be beneficial in managing lipid profiles in animals, potentially reducing the risk of atherosclerosis. Additionally, _F. vesiculuss_ exhibits anti-inflammatory and antioxidant properties, primarily due to its fucoidan content. Fucoidan has been shown to modulate immune responses, inhibit inflammation, and scavenge free radicals, which could be advantageous in preventing chronic inflammation-related disorders in animals [15; 16]. Moreover, _F. vesiculuss_ has demonstrated potential in improving gut health and metabolic functions. Its polysaccharides can remodel gut microbiota and regulate glycolipid metabolism, as evidenced by studies on diabetic rats where _F. vesiculus_ polysaccharides alleviated hyperglycemia, insulin resistance, and dyslipidemia [17]. This suggests that _F. vesiculuss_ could enhance nutrient absorption and metabolic efficiency in animals, contributing to betteroverall health and growth performance. The antioxidant properties of _F. vesicolusus_ are also noteworthy.