Endocrine regulation of ion transport in the avian lower intestine

Laverty, Gary; Elbrønd, Vibeke Sødring; Árnason, Sighvatur S.; Skadhauge, Erik

doi:10.1016/j.ygcen.2006.01.008

Cited by 21 publications

(12 citation statements)

References 52 publications

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“…In all avian species examined to date, the epithelium of the lower intestine reabsorbs Na + , Cl − , and water from isotonic saline perfusion solutions by mechanisms similar to those identified in mammals (Goldstein, 1989 b ; Goldstein & Skadhauge, 2000). Note that tightly regulated control of salt and water balance in the avian lower intestine (Goldstein & Skadhauge, 2000; Laverty et al , 2006) does not conflict with the finding of significant paracellular nutrient absorption (implying relatively higher epithelial permeability) in the small intestine (see ). Epithelial permeability decreases along the length of the intestine, the distal colon of mammals (Powell, 1987) and coprodeum of birds (Goldstein & Skadhauge, 2000) being the least permeable regions.…”

Section: The Role Of the Avian Gut In Salt And Water Regulationmentioning

confidence: 99%

The integration of digestion and osmoregulation in the avian gut

2009

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We review digestion and osmoregulation in the avian gut, with an emphasis on the ways these different functions might interact to support or constrain each other and the ways they support the functioning of the whole animal in its natural environment. Differences between birds and other vertebrates are highlighted because these differences may make birds excellent models for study and may suggest interesting directions for future research. At a given body size birds, compared with mammals, tend to eat more food but have less small intestine and retain food in their gastrointestinal tract (GIT) for shorter periods of time, despite generally higher mass-specific energy demands. On most foods, however, they are not less efficient at digestion, which begs the question how they compensate. Intestinal tissue-specific rates of enzymatic breakdown of substrates and rates of active transport do not appear higher in birds than in mammals, nor is there a demonstrated difference in the extent to which those rates can be modulated during acclimation to different feeding regimes (e.g. diet, relative intake level). One compensation appears to be more extensive reliance on passive nutrient absorption by the paracellular pathway, because the avian species studied so far exceed the mammalian species by a factor of at least two- to threefold in this regard. Undigested residues reach the hindgut, but there is little evidence that most wild birds recover microbial metabolites of nutritional significance (essential amino acids and vitamins) by re-ingestion of faeces, in contrast to many hindgut fermenting mammals and possibly poultry. In birds, there is some evidence for hindgut capacity to breakdown either microbial protein or protein that escapes the small intestine intact, freeing up essential amino acids, and there is considerable evidence for an amino acid absorptive capacity in the hindgut of both avian and mammalian hindgut fermenters. Birds, unlike mammals, do not excrete hyperosmotic urine (i.e. more than five times plasma osmotic concentration). Urine is mixed with digesta rather than directly eliminated, and so the avian gut plays a relatively more important role in water and salt regulation than in mammals. Responses to dehydration and high- and low-salt loads are reviewed. Intestinal absorption of ingested water is modulated to help achieve water balance in one species studied (a nectar-feeding sunbird), the first demonstration of this in any terrestrial vertebrate. In many wild avian species the size and digestive capacity of the GIT is increased or decreased by as much as 50% in response to nutritional challenges such as hyperphagia, food restriction or fasting. The coincident impacts of these changes on osmoregulatory or immune function of the gut are poorly understood.

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Section: The Role Of the Avian Gut In Salt And Water Regulationmentioning

confidence: 99%

The integration of digestion and osmoregulation in the avian gut

2009

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“…Thus, it seems justified to further evaluate the effects of each isoform on LAT2 or 4F2hc expression in LSM cells. Information on the hormonal mechanisms regulating system-L transporter activity is still scarce (33)(34)(35). Steroid hormones may act via multiple mechanisms.…”

Section: Discussionmentioning

confidence: 99%

Progesterone and Mifepristone Regulate L-Type Amino Acid Transporter 2 and 4F2 Heavy Chain Expression in Uterine Leiomyoma Cells

Luo

Yin

Reierstad

et al. 2009

The Journal of Clinical Endocrinology &Amp; Metabolism

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“…The lower intestine (colon and coprodeum) of the domestic fowl represents a special intestinal segment that can be considered as serving a reserve function. Under demanding conditions, such as a low salt diet, the colon and the coprodeum undergo both morphological changes, such as an increase in surface area, and functional changes, such as the greater expression of the electrogenic sodium channels (Laverty et al , 2001, Elbrond et al , 2004, Laverty et al , 2006). …”

Section: Basic Scheme Of Intestinal Ion Transportmentioning

confidence: 99%

Pathophysiology of avian intestinal ion transport

Nighot

2018

World's Poultry Science Journal

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Summary The gut has great importance for the commercial success of poultry production. Numerous ion transporters, exchangers, and channels are present on both the apical and the basolateral membrane of intestinal epithelial cells, and their differential expression along the crypt-villus axis within the various intestinal segments ensures efficient intestinal absorption and effective barrier function. Recent studies have shown that intensive production systems, microbial exposure, and nutritional management significantly affect intestinal physiology and intestinal ion transport. Dysregulation of normal intestinal ion transport is manifested as diarrhoea, malabsorption, and intestinal inflammation resulting into poor production efficiency. This review discusses the basic mechanisms involved in avian intestinal ion transport and the impact of development during growth, nutritional and environmental alterations, and intestinal microbial infections on it. The effect of intestinal microbial infections on avian intestinal ion transport depends on factors such as host immunity, pathogen virulence, and the mucosal organisation of the particular intestinal segment.

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Endocrine regulation of ion transport in the avian lower intestine

Cited by 21 publications

References 52 publications

The integration of digestion and osmoregulation in the avian gut

The integration of digestion and osmoregulation in the avian gut

Progesterone and Mifepristone Regulate L-Type Amino Acid Transporter 2 and 4F2 Heavy Chain Expression in Uterine Leiomyoma Cells

Pathophysiology of avian intestinal ion transport

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