## 2 Endophytes-Current State of the Art
### Endophytes as a Feeding Niche for Animals
Consequently, grazing animal excrements and grazing stresses will affect the tall rescue plant/endophyte physiology [52]. It should also be pointed out that while endophytes can provide various benefits, certain strains can also produce compounds that are toxic to animals [5]. For example, _Neotyphodium_ sp. endophytes in ryegrass and tall rescue produce alkaloids like ergovaline and lolitrem B, which can cause toxicity in grazing animals [52]. This condition, known as fescue toxicosis or ryegrass staggers, leads to issues like poor weight gain, reduced fertility, and heat stress in cattle, sheep and horses [52]. Endophyte-enriched plants can influence the gut microbiome of animals, promoting beneficial microbes and limiting harmful ones [118]. A balanced gut microbiome is crucial for healthy digestion and immune function, which helps animals to resist infections and diseases [5]. In turn, ergot alkaloids produced by endophytes can cause vasoconstriction, leading to circulation problems in livestock, especially during hot weather. Relatively little is known about the immunological implications of endophyte exposure in cattle [123]. For example, ergovaline is an ergot alkaloid found in some endophyte-infected ryegrasses and it has been implicated in the expression of ergotism-like symptoms of grazing livestock, as well as in the protection of the plant against invertebrate predation and abiotic stresses [124]. Ergovaline is produced by an endophyte (_Neotyphodium coenophilatum_) in tall fescue (_Lolium arundinaceum_) commonly found in south-eastern USA. Animals consuming ergovaline-containing feedstuffs appear to have a reduced capacity to maintain a thermoneutral body temperature with rapid changes in ambient temperature [124]. Although there are mechanisms that protect the animal from ergovaline exposure, tissues are very sensitive to ergovaline, indicating that ergovaline is very potent and that small quantities have the potential to cause noticeable physiological effects; decreased circulating prolactin, vasoconstriction and increased susceptibility to heat stress are all linked to the interaction of ergovaline with biogenic amine receptors found throughout the body [124]. In conclusion, endophytes have a dual role in influencing animals, particularly through their effects on plant hosts. While they can offer benefits like growth stimulation and enhanced stress resistance, the potential for toxicity means that their use, especially in forage crops, needs to be managed carefully to avoid adverse effects on animal health [5]. Mentioned interactions evidenced that endophytes are valuable not only for plant health but also for animal productivity and overall health in agricultural settings. Persistence-Perishable of Endophytes in the Gut Microbiome of Animals  
It should be emphasized that endophytic microbes can be short- or long-lived. What is more, they possess a huge diversity of metabolic pathways, which, together with their horizontal gene transfer systems, enable rapid evolution and environmental responses [125]. [PERSON] et al. [126] suggested that these metabolic add ons of microorganisms allow the animal to thrive by adapting to otherwise noncompetitive lifestyles (e.g., feeding on nutrient-poor diets) or environments (e.g., oligotrophic habitats). There is some acceptance that the animal gut microbiome is inherited largely from our mothers at birth, as well as environmental microorganisms with which we come in contact via the food we eat through life [126]. It should be emphasized that this information is important especially for herbivores or those for whom the food mainly consists of plants [125]. It was also suggested that among the various parts of the animal body, the gut is likely the site of the most dynamic and consequential bacterial-signaling benefiting animal hosts. This is due to the sheer number and diversity of its microbes, as well as the inherent permeability and sensitivity of the gut epithelium [127]. [PERSON] et al.