Recent research often lauds the services and beneficial effects of host-associated microbes on animals.However,hosting these microbes may come at a cost.For example,germ-free and antibiotic-treated birds generally gro...Recent research often lauds the services and beneficial effects of host-associated microbes on animals.However,hosting these microbes may come at a cost.For example,germ-free and antibiotic-treated birds generally grow faster than their conventional counterparts.In the wild,juvenile body size is correlated with survival,so hosting a microbiota may incur a fitness cost.Avian altricial nestlings represent an interesting study system in which to investigate these interactions,given that they exhibit the fastest growth rates among vertebrates,and growth is limited by their digestive capacity.We investigated whether reduction and restructuring of the microbiota by antibiotic treatment would:(i)increase growth and food conversion efficiency in nestling house sparrows(Passer domesticus);(ii)alter aspects of gut anatomy or function(particularly activities of digestive carbohydrases and their regulation in response to dietary change);and(iii)whether there were correlations between relative abundances of microbial taxa,digestive function and nestling growth.Antibiotic treatment significantly increased growth and food conversion efficiency in nestlings.Antibiotics did not alter aspects of gut anatomy that we considered but depressed intestinal maltase activity.There were no significant correlations between abundances of microbial taxa and aspects of host physiology.Overall,we conclude that microbial-induced growth limitation in developing birds is not driven by interactions with digestive capacity.Rather,decreased energetic and material costs of immune function or beneficial effects from microbes enriched under antibiotic treatment may underlie these effects.Understanding the costs and tradeoffs of hosting gut microbial communities represents an avenue of future research.展开更多
It is widely known that intestinal capacities such as the enzymatic hydrolysis of carbohydrates,lipids and proteins,and the subsequent absorption of the hydrolyzed products.are evolutionary matched to dietary loads an...It is widely known that intestinal capacities such as the enzymatic hydrolysis of carbohydrates,lipids and proteins,and the subsequent absorption of the hydrolyzed products.are evolutionary matched to dietary loads and feeding behaviors.In this study,we demonstrate that the protein expression of apically located sodium-dependent glucose cotransporter-1(SGLT-1)throughout rat ontogeny is daily adjusted to afford glucose uptake when the load of this metabolically essential monosaccharide in the intestinal lumen is maximum.The jejunal expression of SGLT-1 protein in 14 one-day-old suckling pups was found to increase at dark and early light phase(P<0.05).when they have a better access to mother milk.In weaning21-d-old and juvenile 28-d-old rats,the cotransporter expression was high throughout the entire day(P<0.05).Finally,adult 90-d-old rats showed a well-developed circadian rhythm for SGLT-1 protein(P<0.05).whose expression increased at late light and dark phase when the highest intestinal glucose load was achieved.To our knowledge,these results are the first reporting the daily profile of SGLT-1 expression during rat early developmental stage and may contribute to understand the biological significance of a well-established molecular capacity to deal with the crucial increase of glucose load in the diet during the weaning process.展开更多
基金Funding was provided by the National Science Foundation(IOS1354893 to W.H.K.)the National Institutes of Health(T32DK007673 Training Grant to K.D.K.)grants from Consejo Nacional de Investigaciones Científicas y Técnicas PIP 834 and UNSL CyT 9502 to E.C.V.
文摘Recent research often lauds the services and beneficial effects of host-associated microbes on animals.However,hosting these microbes may come at a cost.For example,germ-free and antibiotic-treated birds generally grow faster than their conventional counterparts.In the wild,juvenile body size is correlated with survival,so hosting a microbiota may incur a fitness cost.Avian altricial nestlings represent an interesting study system in which to investigate these interactions,given that they exhibit the fastest growth rates among vertebrates,and growth is limited by their digestive capacity.We investigated whether reduction and restructuring of the microbiota by antibiotic treatment would:(i)increase growth and food conversion efficiency in nestling house sparrows(Passer domesticus);(ii)alter aspects of gut anatomy or function(particularly activities of digestive carbohydrases and their regulation in response to dietary change);and(iii)whether there were correlations between relative abundances of microbial taxa,digestive function and nestling growth.Antibiotic treatment significantly increased growth and food conversion efficiency in nestlings.Antibiotics did not alter aspects of gut anatomy that we considered but depressed intestinal maltase activity.There were no significant correlations between abundances of microbial taxa and aspects of host physiology.Overall,we conclude that microbial-induced growth limitation in developing birds is not driven by interactions with digestive capacity.Rather,decreased energetic and material costs of immune function or beneficial effects from microbes enriched under antibiotic treatment may underlie these effects.Understanding the costs and tradeoffs of hosting gut microbial communities represents an avenue of future research.
基金supported by PIP 2016-2018 by CONICET,PROICO 2-0814 and PROICO 2-0516 by CyT-UNSL and PICT-201-0595 by Agencia Nacional de Promocion Cientifica y Tecnologica
文摘It is widely known that intestinal capacities such as the enzymatic hydrolysis of carbohydrates,lipids and proteins,and the subsequent absorption of the hydrolyzed products.are evolutionary matched to dietary loads and feeding behaviors.In this study,we demonstrate that the protein expression of apically located sodium-dependent glucose cotransporter-1(SGLT-1)throughout rat ontogeny is daily adjusted to afford glucose uptake when the load of this metabolically essential monosaccharide in the intestinal lumen is maximum.The jejunal expression of SGLT-1 protein in 14 one-day-old suckling pups was found to increase at dark and early light phase(P<0.05).when they have a better access to mother milk.In weaning21-d-old and juvenile 28-d-old rats,the cotransporter expression was high throughout the entire day(P<0.05).Finally,adult 90-d-old rats showed a well-developed circadian rhythm for SGLT-1 protein(P<0.05).whose expression increased at late light and dark phase when the highest intestinal glucose load was achieved.To our knowledge,these results are the first reporting the daily profile of SGLT-1 expression during rat early developmental stage and may contribute to understand the biological significance of a well-established molecular capacity to deal with the crucial increase of glucose load in the diet during the weaning process.
