Fish tanks in the facilities for animal studies (1280x720)
Enteritis: an intestinal pathology characterised by inflammation, physiological degradation and dysbiosis of the intestine. In extremis, it can degrade fish welfare, reduce feed conversion efficiency and increase susceptibility to disease.
Brewer’s yeast derived functional feed additives to alleviate enteritis in Atlantic salmon
Historically, aquafeeds – fish meal – have been rich in wild sources of marine protein. However, fish meal cannot supply the demand for the growing aquaculture industry and this has seen a major drive to use high levels of plant proteins as feed. 
Whilst this is a more sustainable approach, many plant-derived raw materials can cause intestinal inflammation in fishes (enteritis) as they contain anti-nutritional factors (ANFs) such as alkaloids, saponins, gossypol, lectins and fibres. 
This intestinal inflammatory pathology is characterised by changes in absorptive cells, elevated pro-inflammatory cytokine production, endocytic blocking, apoptosis, disruption of microvilli and dysbiosis.
Ultimately, this reduces welfare and growth and increases the chance of disease.
Atlantic salmon are particularly vulnerable to the antinutritional factors present in soybean meal which can manifest in an intestinal inflammatory response, known as soybean meal induced enteritis (SBMIE). 
Using an Atlantic salmon SBMIE model we are testing the efficacy, and elucidating the modes of action, of brewer's yeast derived functional feed additives rich in MOS, β-glucans, nucleotides and other bioactive compounds to prevent or treat this pathology. Our findings indicate that SBMIE an be alleviated with the application of dietary brewer's yeast products.
Application of functional feed additives to alleviate intestinal disorders
With fish welfare being increasingly recognised by the public, regulatory bodies and aquaculture industries face the challenge of evolving feed formulations with plant proteins without harmful effects. Functional feed additives – yeast-derived prebiotics, β-glucans, nucleotides – can modulate the microbiota and intestinal inflammatory mediators leading to improved intestinal morphology of fish under non-enteritis conditions.
Using a ‘zebrafish intestinal inflammatory model’, this research will determine the efficacy and modes of action of functional feed additives to alleviate inflammation. This has the potential to fast-track improved dietary formulations of feeds that can then be applied to other aquaculture species and land farm animals.
Fish tanks in the facilities for animal studies (1280x720)

Determination of the potential of yeast-derived functional feed additives to alleviate enteritis-induced dysbiosis in Atlantic Salmon 

The mucosal surfaces of fish are host to an abundant and diverse community of commensal microbiota. The gastrointestinal (GI) microbiota and their metabolites in particular, play key roles in fishes homeostasis – the process by which they maintain stability whilst adjusting to varying conditions – digestive function, gastric development, mucosal tolerance, immunity and disease resistance.
Dietary functional feed additives (FFAs) are increasingly used to enhance fish microbial balance, welfare and health. This research will aim to apply yeast derived FFAs to alleviate enteritis – intestinal inflammation, leaky gut and dysbiosis (a bacterial imbalance).
This research will answer key questions and fill significant knowledge gaps relating to salmon gut microbiome, dysbiosis and the efficacy of yeast derived FFAs to fortify the gut microbiobe during intestinal inflammation by using higher taxonomic resolution from full-length 16S metabarcoding to provide a better knowledge of the diversity, and a deeper understanding of the roles, of the GI microbes. 
Atlantic Salmon farm pen

Aquaculture: Fish Health and Nutrition

The University of Plymouth has a strong research track record in the fields of fish health and nutrition dating back more than three decades. 
Led by Dr Daniel Merrifield, the Fish Health and Nutrition research team actively engages with hatcheries, aquaculture farms and various other organisations, nationally and internationally, to support and conduct research and development at fundamental and applied levels contributing to United Nations Sustainable Development Goals, 2 (Zero Hunger), 12 (Sustainable Consumption and Production) and 14 (Life Below Water).
Sustainable aquaculture facilities