scholarly journals Consistent changes in the intestinal microbiota of Atlantic salmon fed insect meal diets

Author(s):  
Yanxian Li ◽  
Karina Gajardo ◽  
Alexander Jaramillo-Torres ◽  
Trond M. Kortner ◽  
Åshild Krogdahl

Abstract Background: Being part of fish's natural diets, insects have become a realistic, sustainable feed ingredient for aquaculture. While nutritional values of insects have been extensively studied in various fish species, their impact on the fish microbiota remains to be fully explored. In an 8-week freshwater feeding trial, Atlantic salmon ( Salmo salar ) were fed either a commercially relevant reference diet or an insect meal diet wherein black soldier fly ( Hermetia illucens ) larvae meal comprised 60% of total ingredients. Microbiota of digesta and mucosa origin from the proximal and distal intestine were collected and profiled along with feed and water samples. Results: The insect meal diet markedly modulated the salmon intestinal microbiota. Overall, the microbial diversity was lower in the digesta of salmon fed the insect meal diet but higher in the mucosa. A group of bacterial genera, dominated by members of the Bacillaceae family, was enriched in salmon fed the insect meal diet, which confirms our previous findings in a seawater feeding trial. We also found that microbiota in the intestine closely resembled that of the feeds but was distinct from the water microbiota. Notably, bacterial genera associated with the diet effects were also present in the feeds. Conclusions: We conclude that salmon fed the insect meal diets show consistent changes in the intestinal microbiota. The next challenge is to evaluate the extent to which these alterations are attributable to feed microbiota and dietary nutrients and what these changes mean for fish physiology and health.

2021 ◽  
Author(s):  
Yanxian Li ◽  
Karina Gajardo ◽  
Alexander Jaramillo-Torres ◽  
Trond M. Kortner ◽  
Ashild Krogdahl

Being part of fish's natural diets, insects have become a realistic, sustainable feed ingredient for aquaculture. While nutritional values of insects have been extensively studied in various fish species, their impact on the fish microbiota remains to be fully explored. In an 8-week freshwater feeding trial, Atlantic salmon (Salmo salar) were fed either a commercially relevant reference diet or an insect meal diet wherein black soldier fly (Hermetia illucens) larvae meal comprised 60% of total ingredients. Microbiota of digesta and mucosa origin from the proximal and distal intestine were collected and profiled along with feed and water samples. The insect meal diet markedly modulated the salmon intestinal microbiota . Overall, the microbial diversity was lower in the digesta of salmon fed the insect meal diet but higher in the mucosa. A group of bacterial genera, dominated by members of the Bacillaceae family, was enriched in salmon fed the insect meal diet, which confirms our previous findings in a seawater feeding trial. We also found that microbiota in the intestine closely resembled that of the feeds but was distinct from the water microbiota. Notably, bacterial genera associated with the diet effects were present in the feeds as well. In conclusion, our results show consistent changes in the intestinal microbiota of Atlantic salmon fed diets containing black soldier fly larvae meal.


2022 ◽  
Vol 4 (1) ◽  
Author(s):  
Yanxian Li ◽  
Karina Gajardo ◽  
Alexander Jaramillo-Torres ◽  
Trond M. Kortner ◽  
Åshild Krogdahl

Abstract Background Being part of fish's natural diets, insects have become a practical alternative feed ingredient for aquaculture. While nutritional values of insects have been extensively studied in various fish species, their impact on the fish microbiota remains to be fully explored. In an 8-week freshwater feeding trial, Atlantic salmon (Salmo salar) were fed either a commercially relevant reference diet or an insect meal diet wherein black soldier fly (Hermetia illucens) larvae meal comprised 60% of total ingredients. Microbiota of digesta and mucosa origin from the proximal and distal intestine were collected and profiled along with feed and water samples. Results The insect meal diet markedly modulated the salmon intestinal microbiota. Salmon fed the insect meal diet showed similar or lower alpha-diversity indices in the digesta but higher alpha-diversity indices in the mucosa. A group of bacterial genera, dominated by members of the Bacillaceae family, was enriched in salmon fed the insect meal diet, which confirms our previous findings in a seawater feeding trial. We also found that microbiota in the intestine closely resembled that of the feeds but was distinct from the water microbiota. Notably, bacterial genera associated with the diet effects were also present in the feeds. Conclusions We conclude that salmon fed the insect meal diets show consistent changes in the intestinal microbiota. The next challenge is to evaluate the extent to which these alterations are attributable to feed microbiota and dietary nutrients, and what these changes mean for fish physiology and health.


2020 ◽  
Author(s):  
Yanxian Li ◽  
Leonardo Bruni ◽  
Alexander Jaramillo-Torres ◽  
Karina Gajardo ◽  
Trond M. Kortner ◽  
...  

Abstract Background: Intestinal digesta is commonly used for studying responses of microbiota to dietary shifts, yet evidence is accumulating that it represents an incomplete view of the intestinal microbiota. The present work aims to investigate the differences between digesta- and mucosa-associated intestinal microbiota in Atlantic salmon ( Salmo salar ) and how they may respond differently to dietary perturbations. In a 16-week seawater feeding trial, Atlantic salmon were fed either a commercially-relevant reference diet or an insect meal diet containing ~15% black soldier fly ( Hermetia illucens ) larvae meal. The digesta- and mucosa-associated distal intestinal microbiota were profiled by 16S rRNA gene sequencing. Results: Regardless of diet, we observed substantial differences between digesta- and mucosa-associated intestinal microbiota. Microbial richness and diversity were much higher in the digesta than the mucosa. The insect meal diet altered the distal intestinal microbiota resulting in higher microbial richness and diversity. The diet effect, however, depended on the sample origin. Digesta-associated intestinal microbiota showed more pronounced changes than the mucosa-associated microbiota. Multivariate association analyses identified two mucosa-enriched taxa, Brevinema andersonii and unclassified Spirochaetaceae , associated with the expression of genes related to immune responses and barrier function in the distal intestine, respectively. Conclusions: Our data show that salmon intestinal digesta and mucosa harbor microbial communities with clear differences. Mucosa-associated intestinal microbiota seems more resilient to variations in the diet composition than digesta-associated intestinal microbiota. To fully unveil the response of intestinal microbiota to dietary changes, concurrent profiling of digesta- and mucosa-associated intestinal microbiota is recommended whenever feasible.


2007 ◽  
Vol 97 (4) ◽  
pp. 699-713 ◽  
Author(s):  
Anne Marie Bakke-McKellep ◽  
Michael H. Penn ◽  
Patricia Mora Salas ◽  
Ståle Refstie ◽  
Sigmund Sperstad ◽  
...  

Soyabean meal (SBM)-induced enteritis in the distal intestine of the teleost Atlantic salmon (Salmo salar L.) and other salmonids may be considered a model for diet-related mucosal disorders in other animals and man. The role of the intestinal microbiota in its pathogenesis was explored. Compared to diets containing fishmeal (FM) as the sole protein source, responses to extracted SBM or the prebiotic inulin, with or without oxytetracycline (OTC) inclusion, were studied following a 3-week feeding trial. Intestinal microbiota, organosomatic indices and histology, as well as immunohistochemical detection of proliferating cell nuclear antigen (PCNA), heat shock protein 70 (HSP70) and caspase-3-positive cells in the distal intestine, were studied. Distal intestine somatic indices (DISI) were higher in inulin and lower in SBM compared to FM-fed fish. The low DISI caused by SBM corresponded with histological changes, neither of which was affected by OTC, despite a significant decrease in adherent bacteria count. Image analysis of PCNA-stained sections showed a significant increase in the proliferative compartment length in SBM-fed fish, accompanied by apparent increases in reactivity to HSP70 and caspase-3 along the mucosal folds, indicating induction of cellular repair and apoptosis, respectively. Fish fed the SBM diet had higher total number as well as a more diverse population composition of adherent bacteria in the distal intestine. Thus SBM-induced enteritis is accompanied by induction of distal intestinal epithelial cell protective responses and changes in microbiota. Putative involvement of bacteria in the inflammatory response merits further investigation.


2020 ◽  
Author(s):  
Yanxian Li ◽  
Leonardo Bruni ◽  
Alexander Jaramillo-Torres ◽  
Karina Gajardo ◽  
Trond M. Kortner ◽  
...  

Intestinal digesta is commonly used for studying responses of microbiota to dietary shifts, yet evidence is accumulating that it represents an incomplete view of the intestinal microbiota. In a 16-week seawater feeding trial, Atlantic salmon (Salmo salar) were fed either a commercially-relevant reference diet or an insect meal diet containing 15% black soldier fly (Hermetia illucens) larvae meal. The digesta- and mucosa-associated distal intestinal microbiota were profiled by 16S rRNA gene sequencing. Regardless of diet, we observed substantial differences between digesta- and mucosa-associated intestinal microbiota. Microbial richness and diversity were much higher in the digesta than the mucosa. The insect meal diet altered the distal intestinal microbiota resulting in higher microbial richness and diversity. The diet effect, however, depended on the sample origin. Digesta-associated intestinal microbiota showed more pronounced changes than the mucosa-associated microbiota. Lastly, multivariate association analyses identified two mucosa-enriched taxa, Brevinema andersonii and unclassified Spirochaetaceae, associated with the expression of genes related to immune responses and barrier function in the distal intestine, respectively. Overall, our data clearly indicate that responses in digesta- and mucosa-associated microbiota to dietary inclusion of insect meal differ, with the latter being more resilient to dietary changes.


2020 ◽  
Author(s):  
Yanxian Li ◽  
Leonardo Bruni ◽  
Alexander Jaramillo-Torres ◽  
Karina Gajardo ◽  
Trond M. Kortner ◽  
...  

Abstract Background: Intestinal digesta is commonly used for studying responses of microbiota to dietary shifts, yet evidence is accumulating that it represents an incomplete view of the intestinal microbiota. The present work aims to investigate the differences between digesta- and mucosa-associated intestinal microbiota in Atlantic salmon (Salmo salar) and how they may respond differently to dietary perturbations. In a 16-week seawater feeding trial, Atlantic salmon were fed either a commercially-relevant reference diet or an insect meal diet containing ~15% black soldier fly (Hermetia illucens) larvae meal. The digesta- and mucosa-associated distal intestinal microbiota were profiled by 16S rRNA gene sequencing. Results: Regardless of diet, we observed substantial differences between digesta- and mucosa-associated intestinal microbiota. Microbial richness and diversity were much higher in the digesta than the mucosa. The insect meal diet altered the distal intestinal microbiota resulting in higher microbial richness and diversity. The diet effect, however, depended on the sample origin. Digesta-associated intestinal microbiota showed more pronounced changes than the mucosa-associated microbiota. Multivariate association analyses identified two mucosa-enriched taxa, Brevinema andersonii and Spirochaetaceae, associated with the expression of genes related to immune responses and barrier function in the distal intestine, respectively. Conclusions: Our data show that salmon intestinal digesta and mucosa harbor microbial communities with clear differences. Mucosa-associated intestinal microbiota seems more resilient to variations in the diet composition than digesta-associated intestinal microbiota. To fully unveil the response of intestinal microbiota to dietary changes, concurrent profiling of digesta- and mucosa-associated intestinal microbiota is recommended whenever feasible.


2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Yanxian Li ◽  
Leonardo Bruni ◽  
Alexander Jaramillo-Torres ◽  
Karina Gajardo ◽  
Trond M. Kortner ◽  
...  

Abstract Background Intestinal digesta is commonly used for studying responses of microbiota to dietary shifts, yet evidence is accumulating that it represents an incomplete view of the intestinal microbiota. The present work aims to investigate the differences between digesta- and mucosa-associated intestinal microbiota in Atlantic salmon (Salmo salar) and how they may respond differently to dietary perturbations. In a 16-week seawater feeding trial, Atlantic salmon were fed either a commercially-relevant reference diet or an insect meal diet containing ~ 15% black soldier fly (Hermetia illucens) larvae meal. The digesta- and mucosa-associated distal intestinal microbiota were profiled by 16S rRNA gene sequencing. Results Regardless of diet, we observed substantial differences between digesta- and mucosa-associated intestinal microbiota. Microbial richness and diversity were much higher in the digesta than the mucosa. The insect meal diet altered the distal intestinal microbiota resulting in higher microbial richness and diversity. The diet effect, however, depended on the sample origin. Digesta-associated intestinal microbiota showed more pronounced changes than the mucosa-associated microbiota. Multivariate association analyses identified two mucosa-enriched taxa, Brevinema andersonii and Spirochaetaceae, associated with the expression of genes related to immune responses and barrier function in the distal intestine, respectively. Conclusions Our data show that salmon intestinal digesta and mucosa harbor microbial communities with clear differences. While feeding insects increased microbial richness and diversity in both digesta- and mucosa-associated intestinal microbiota, mucosa-associated intestinal microbiota seems more resilient to variations in the diet composition. To fully unveil the response of intestinal microbiota to dietary changes, concurrent profiling of digesta- and mucosa-associated intestinal microbiota is recommended whenever feasible. Specific taxa enriched in the intestinal mucosa are associated to gene expression related to immune responses and barrier function. Detailed studies are needed on the ecological and functional significance of taxa associated to intestinal microbiota dwelling on the mucosa.


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