Spray-Dried Porcine Plasma Promotes the Association Between Metabolic and Immunological Processes at Transcriptional Level in Gilthead Sea Bream (Sparus aurata) Gut

Abstract

The spray-dried porcine plasma (SDPP) is an abattoir by-product used in animal nutrition with beneficial effects reported in livestock and commercial aquatic species. Previous results have found that the dietary inclusion of SDPP in gilthead sea bream (Sparus aurata) increased the density of intestinal goblet cells, and it did not result in significant changes in the autochthonous microbiota. However, there is no comprehensive data on the mechanisms that could take place on the intestine of gilthead sea bream fed with an SDPP-supplemented diet. For this reason, this study aimed to unveil the biological mechanisms modulated in response to the dietary administration of SDPP in the gilthead sea bream gut. To achieve this goal, we made a microarrays-based transcriptomic approach in gut samples from gilthead sea bream fed with an SDPP-supplemented diet for 95 days. As control diet, we used a protein-rich commercial feed (51% crude protein, 17% crude fat, and 20.6 MJ/kg gross energy) which was supplemented with 3% SDPP at the expense of LT70 fishmeal. The microarray analyses showed a total of 803 (468 up- and 335 down-regulated) differential expressed genes (DEGs). The functional network analysis revealed that dietary inclusion of SDPP induced sustained changes in 120 biological processes, grouped in 12-clusters. Among them, the metabolic-related process (cellular catabolic process, organic substance catabolic process, protein metabolism process), protein transport, and leukocyte mediated immunity interacted in the leading interactome network. This evidence confirms the previous evidence of the enhancement of the mucosal health status in response to the dietary administration of SDPP and provides further understanding of the mode of action of this ingredient in aquafeeds.

Evaluating the Functional Properties of Spray-Dried Porcine Plasma in Gilthead Seabream (Sparus aurata) Fed Low Fish Meal Diets

“…In addition, the beneficial effects on skin mucus in response to protein hydrolysates had also been confirmed in meagre [ 19 ] and seabream [ 14 , 18 ], benefits that could be imputed to the bioactive compounds existing in SDPP, such as growth factors, albumins, immunoglobulins, and biological active peptides, which may moderate the immunomodulatory and anti-inflammatory effects [ 64 , 65 ]. These dietary systemic and mucosal effects confirmed the prior evidence of the metabolic, immune, and protein transport processes that occur in response to SDPP at the mucosal tissue level [ 15 , 18 ]. In similar studies conducted by Vallejos et al [ 15 ] and Reyes-López et al [ 18 ], SDPP was tested at higher levels of FM inclusion (47%), and the results from the above-mentioned studies indicated a remarkable association between immunity, protein transport, and metabolic-associated processes in response to the SDPP diet.…”

“…As it has been previously stated, functional feeds are commonly used to modulate the immune and stress responses; however, predicting functional response is very difficult due to complex interactions between dietary ingredients [ 33 ]. Although there are benefits of SDPP in terms of growth, feed efficiency and host’s immunity in diets formulated with high levels of FM (46%) [ 13 , 15 , 18 ], there is not information on whether low FM diets (2%), such as those tested in the current study and in our previous studies [ 14 ], would behave similarly to full FM ones. Thus, in this study, the authors aimed to evaluate the potential immunomodulatory effect of SDPP inclusion in diets with very low levels of FM (2%) by means of an ex vivo assay.…”

“…The term “functional feed” has arisen as a nutritional strategy to improve the general health status, including welfare and stress in farmed aquatic organisms [ 1 , 27 ]. Among different animal by-products, SDPP included in animal diets benefited systemic health and mucosal performance both in livestock [ 10 ] and aquaculture species [ 15 , 18 ]. Blood by-products are an untapped source of high-quality ingredients for aquafeeds, containing a broad variety of amino acids, proteins, hormones, growth factors, bioactive peptides, and cytokines [ 10 , 28 ].…”

“…In livestock production, SDP is considered a promising functional ingredient as an alternative to the use of antibiotics, due to growth and immunity promotion, as well as reducing both morbidity and mortality [ 9 , 10 , 11 ]. Regarding aquatic species, several studies have reported that spray-dried porcine plasma (SDPP) enhances growth in rainbow trout ( Oncorhynchus mykiss ) [ 12 ], gilthead sea bream ( Sparus aurata ) [ 13 , 14 , 15 ], and Nile tilapia ( Oreochromis niloticus ) [ 16 ]. Different authors have postulated that these results might be explained by the higher digestibility of SDPP, the improvement of feed efficiency and feed intake, as well as its content in growth factors.…”

“…In addition to its use as a source of highly digestible dietary protein source, SDPP has also been recommended in livestock and aquaculture feeds as a source of immunological support due to its immune modulatory components, including immunoglobulins and bioactive peptides [ 10 , 17 ]. In particular, aquafeeds containing SDPP enhanced the local gut and systemic immunity in sea bream [ 13 , 15 , 18 ], leukocyte, lymphocyte, and neutrophil counts in tilapia [ 16 ], and skin mucus antibacterial capacity in meagre Argyrosomus regius [ 19 ]. Although the benefits of SDPP in livestock diets are well known, there is limited literature on the immunomodulatory effects of its dietary inclusion in aquatic feeds, especially when fish may be challenged by different biotic and abiotic stressors.…”