A neurochemical biogeography of the broiler chicken intestinal tract

Uso de probióticos y sus efectos en el bienestar de la gallina ponedora

“…foram propostos, dentre eles a viabilização da atividade neuroquímica (Jiang et al, 2022), por meio da manutenção da microbiota equilibrada, resultando em melhor saúde e integridade intestinal. Esta ação facilita a síntese e secreção de neurotransmissores como a serotonina, estimulando o eixo intestino-cérebro (Jiang et al, 2022;Lyte et al, 2022;Cheng et al, 2001;Cheng et al, 2019). O benefício mais evidente, que é a melhoria no bem-estar das aves, advém do aumento nas concentrações de serotonina circulante, afinal 90% deste neurotransmissor, conhecido popularmente como "hormônio da felicidade" é produzido no intestino (Almeida Paz et al, 2019).…”

The Relationship between Performance, Body Composition, and Processing Yield in Broilers: A Systematic Review and Meta-Regression

“…All data available fitting the required criteria were included in this study; however, the factors tested in the primary studies were mainly focused on nutrition. Furthermore, none of the studies included specific factors that may influence the relationships established herein, such as stress [ 61 ], gut microbiota changes [ 62 ], and coccidia, Clostridium perfringens , or feed ingredient-associated specific enteric challenges [ 18 ]. Therefore, the relationships established herein may change with new data.…”

The Impact of Probiotic Bacillus subtilis on Injurious Behavior in Laying Hens

“…Under normal rearing conditions, chickens adapted to rearing-related factors have a balanced gut microbiota composition, maintaining its optimal function in feed digestion, nutrient resorption, synthesis of biochemicals, and neural and immune regulation [ 112 , 113 ]. However, under certain conditions, these management-associated stressors have negative effects on the gut microbial structure and functions by (1) disrupting the commensal bacterial populations and colonization (the stability of the gut microbiota), thus reducing beneficial bacteria and increasing pathogenic variant (low-grade inflammation); (2) increasing pathogen survival and invasive capability (bacterial translocation to increase neuroinflammation); (3) disrupting the absorption of nutrients and minerals including calcium, a key bone mineral; (4) disrupting microbial neuroendocrine functions (producing several signaling molecules and neurochemicals including serotonin (5-HT); (5) disrupting the gut epithelial barrier, thereby increasing intestinal permeability causing the gut to leak certain bacteria and harmful substances into the bloodstream (leaky gut), resulting in inflammation and or infection; and (6) damaging epithelial cells, thus producing free radicals and reducing antioxidant efficacy (oxidative stress) [ 31 , 114 , 115 , 116 , 117 , 118 ]. These changes resulted from the gut microbiota alterations (imbalanced microbiota composition with dysfunction) that influenced host behavioral display and health status via the nerve systems (i.e., the vagus nerve, enteric nerve, and autonomic nervous system), hormone signaling, immune system, and microbial metabolites (such as short chain fatty acids) to regulate the function of the gut–brain and gut–immune axes ( Figure 3 ).…”

“…Probiotics are commensal bacteria (“direct-fed microbials”, DFM) that offer potential health beneficial effects to the host’s stress response (acute, chronic or both). Several commercial probiotics have been used in poultry production [ 150 , 151 ], and numerous studies have shown that probiotics aid chickens in adapting to their environment and improving their health and welfare by: (1) altering the microbiota profile with beneficial bacteria to prevent the growth of pathogens and to compete with enteric pathogens for the limited availability of nutrient and attachment sites; (2) producing bacteriocins (such as bacteriostatic and bactericidal substances) with antimicrobial function and short chain fatty acids to regulate the activity of intestinal digestive enzymes and energy homeostasis; (3) modulating gut and systemic immunity; (4) restoring the intestinal barrier integrity preventing pathogens from crossing the mucosal epithelium; (5) stimulating the endocrine system and attenuating stress-induced disorders of the HPA and/or sympathetic-adrenal-medullary (SMA) axes via the gut–brain axis; (6) inducing epithelial heat shock proteins to protect cells from oxidative damage; and (7) synthesis and secretion of neurotransmitters such as 5-HT and tryptophan [ 104 , 107 , 113 , 115 , 152 ] ( Figure 3 ).…”