The effects of starvation on digestive tract function and structure in juvenile southern catfish (Silurus meridionalis Chen)

Zeng, Ling-Qing; Li, Fengjie; Li, Xiu-Ming; Cao, Zhen-Dong; Fu, Shi‐Jian; Zhang, Yaoguang

doi:10.1016/j.cbpa.2012.02.022

Cited by 83 publications

(62 citation statements)

References 46 publications

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“…In the current study, the general decline in RMR during fasting may have, at least partially, reflected its progressive downregulation. In fishes, food deprivation causes rapid changes in the morphology of the intestine, within 2−3 days, that can include reduction in gut length and surface area, a decline in complexity and thickness of the mucosae of the small intestine, and reduced activities of digestive enzymes (Bar and Volkoff, 2012;Lignot, 2012;Zeng et al, 2012;Zeng et al, 2014). Such morphological and biochemical changes during fasting have been shown to influence digestion of a subsequent first meal in the southern catfish Silurus meridionalis (Zeng et al, 2014), with a dampening and slowing of the SDA response, similar to the current study.…”

Section: Discussionmentioning

confidence: 99%

“…When ectotherms are fasted they can show a progressive decline in metabolic rate, an energy-saving strategy that at least partially reflects progressive downregulation of superfluous organ systems, in particular the digestive tract (Wang et al, 2006;Hervant, 2012;Lignot, 2012;Zeng et al, 2012;Zeng et al, 2014). Phenotypes tolerant of food deprivation may implement a progressive downregulation of the gastrointestinal tract as fasting proceeds, with an associated decline in metabolic rate that manifests itself progressively over time.…”

Section: Introductionmentioning

confidence: 99%

“…Rapid growth phenotypes may elect to maintain function of organs systems such as the gut, and their associated metabolic costs, for longer during food deprivation, to be able to quickly take advantage of any meals that present themselves. Gut downregulation is not easy to measure without sacrificing animals but there is evidence that one of its consequences can be a slowing and dampening of the SDA response (Zeng et al, 2012;Zeng et al, 2014), presumably because the uptake of nutrients at the intestine is retarded.…”

Section: Introductionmentioning

confidence: 99%

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Physiological mechanisms underlying individual variation in tolerance of food deprivation in juvenile European sea bass, Dicentrarchus labrax

McKenzie

Vergnet

Chatain

et al. 2014

Journal of Experimental Biology

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Although food deprivation is a major ecological pressure in fishes, there is wide individual variation in tolerance of fasting, whose mechanistic bases are poorly understood. Two thousand individually tagged juvenile European sea bass were submitted to two 'fasting/feeding' cycles each comprising 3 weeks of food deprivation followed by 3 weeks of ad libitum feeding at 25°C. Rates of mass loss during the two fasting periods were averaged for each individual to calculate a population mean. Extreme fasting tolerant (FT) and sensitive (FS) phenotypes were identified that were at least one and a half standard deviations, on opposing sides, from this mean. Respirometry was used to investigate two main hypotheses: (1) tolerance of food deprivation reflects lower mass-corrected routine metabolic rate (RMR) in FT phenotypes when fasting, and (2) tolerance reflects differences in substrate utilisation; FT phenotypes use relatively less proteins as metabolic fuels during fasting, measured as their ammonia quotient (AQ), the simultaneous ratio of ammonia excretion to RMR. There was no difference in mean RMR between FT and FS over 7 days fasting, being 6.70±0.24 mmol h −1 fish −1 (mean ± s.e.m., N=18) versus 6.76±0.22 mmol h −1 fish −1 (N=17), respectively, when corrected to a body mass of 130 g. For any given RMR, however, the FT lost mass at a significantly lower rate than FS, overall 7-day average being 0.72±0.05 versus 0.90±0.05 g day −1 fish −1 , respectively (P<0.01, ttest). At 20 h after receiving a ration equivalent to 2% body mass as food pellets, ammonia excretion and simultaneous RMR were elevated and similar in FT and FS, with AQs of 0.105±0.009 and 0.089±0.007, respectively. At the end of the period of fasting, ammonia excretion and RMR had fallen in both phenotypes, but AQ was significantly lower in FT than FS, being 0.038±0.004 versus 0.061±0.005, respectively (P<0.001, t-test). There was a direct linear relationship between individual fasted AQ and rate of mass loss, with FT and FS individuals distributed at opposing lower and upper extremities, respectively. Thus the difference between the phenotypes in their tolerance of food deprivation did not depend upon their routine energy use when fasting. Rather, it depended RESEARCH ARTICLE 1 UMR5119, Ecologie des systèmes marins côtiers (ECOSYM), Place Eugène Bataillon, Université Montpellier 2, 34095 Montpellier Cedex 5, France. upon their relative use of tissue proteins as metabolic fuels when fasting, which was significantly lower in FT phenotypes.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Physiological mechanisms underlying individual variation in tolerance of food deprivation in juvenile European sea bass, Dicentrarchus labrax

McKenzie

Vergnet

Chatain

et al. 2014

Journal of Experimental Biology

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“…However, we have not observed the notable changes of Bmgrp78 expression in silkworm midgut when deprived of food. This phenomenon may due to the flexibility of the gastrointestinal tract of animals, which can conserve energy through self-digestion in response to food deprivation (Chediack et al 2012;Zeng et al 2012). Interestingly, other studies reported that GRP78 protein level was higher in brain than in other tissues during animal hibernation (Lee et al 2002;Mamady & Storey 2006).…”

Section: Discussionmentioning

confidence: 99%

Molecular cloning and expression analysis of glucose-regulated protein 78 (GRP78) gene in silkworm Bombyx mori

Xing-zi

2013

Biologia

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GRP78 (78 kDa glucose-regulated protein), also known as BiP (immunoglobulin heavy-chain-binding protein), is an essential regulator of endoplasmic reticulum (ER) homeostasis because of its multiple functions in protein folding, ER calcium binding, and controlling of the activation of transmembrane ER stress sensors. In this report, we cloned the full-length cDNA of GRP78 from silkworm Bombyx mori (BmGRP78). It is 2645 bp, including an open reading frame (ORF) of 1977 bp encoding a polypeptide of 658 amino acids. We sequenced the ORF sequence from genomic DNA, and found only one intron (104 bp) existed in Bmgrp78 gene structure. The deduced amino acid sequence of Bmgrp78 carries the ER retention signal KDEL at its C-terminus and is highly homologous to GRP78 of Fenneropenaeus chinensis (83.59%) and Homo sapiens (80.27%). RT-PCR analysis shows that Bmgrp78 is ubiquitously expressed in tissues of silkworm. Heat shock over 35• C notably enhanced the expression of Bmgrp78 in head tissues. In response to starvation, the transcript level of Bmgrp78 in head tissues was 2.8-fold (at WS stage) and 3.2-fold (at SD1 stage) higher than the control level, but it remained stable in the midgut tissues. After silkworms were challenged by bacteria, the relative expression level of Bmgrp78 in midgut was up-regulated and reached maximal level at 24 hour after injection, and remained higher level than that of controls at about 48 hour post challenge. We infer that BmGRP78 may play important roles in chaperoning, protein folding and immune function of silkworm.

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“…Fasting and refeeding does not always affect stomach mass, as numerous species of anurans and reptiles lack any change in the wet mass of the stomach after a month of fasting, followed by refeeding (422,487,493,494). Fasting and refeeding can generate changes at the ultrastructural level of the gastric epithelium (257,602). For the oxyntopeptic cells of the Burmese python, fasting leads to an accumulation of zymogen granules and the development of a thick apical tubulovesicular system.…”

Section: Stomachmentioning

confidence: 98%

Integrative Physiology of Fasting

Secor

Carey

2016

Comprehensive Physiology

149

144

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Extended bouts of fasting are ingrained in the ecology of many organisms, characterizing aspects of reproduction, development, hibernation, estivation, migration, and infrequent feeding habits. The challenge of long fasting episodes is the need to maintain physiological homeostasis while relying solely on endogenous resources. To meet that challenge, animals utilize an integrated repertoire of behavioral, physiological, and biochemical responses that reduce metabolic rates, maintain tissue structure and function, and thus enhance survival. We have synthesized in this review the integrative physiological, morphological, and biochemical responses, and their stages, that characterize natural fasting bouts. Underlying the capacity to survive extended fasts are behaviors and mechanisms that reduce metabolic expenditure and shift the dependency to lipid utilization. Hormonal regulation and immune capacity are altered by fasting; hormones that trigger digestion, elevate metabolism, and support immune performance become depressed, whereas hormones that enhance the utilization of endogenous substrates are elevated. The negative energy budget that accompanies fasting leads to the loss of body mass as fat stores are depleted and tissues undergo atrophy (i.e., loss of mass). Absolute rates of body mass loss scale allometrically among vertebrates. Tissues and organs vary in the degree of atrophy and downregulation of function, depending on the degree to which they are used during the fast. Fasting affects the population dynamics and activities of the gut microbiota, an interplay that impacts the host's fasting biology. Fasting-induced gene expression programs underlie the broad spectrum of integrated physiological mechanisms responsible for an animal's ability to survive long episodes of natural fasting.

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The effects of starvation on digestive tract function and structure in juvenile southern catfish (Silurus meridionalis Chen)

Cited by 83 publications

References 46 publications

Physiological mechanisms underlying individual variation in tolerance of food deprivation in juvenile European sea bass, Dicentrarchus labrax

Physiological mechanisms underlying individual variation in tolerance of food deprivation in juvenile European sea bass, Dicentrarchus labrax

Molecular cloning and expression analysis of glucose-regulated protein 78 (GRP78) gene in silkworm Bombyx mori

Integrative Physiology of Fasting

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