Vegetable Ingredients Research Articles

227 Apparent and true digestibility of minerals in animal and vegetable ingredient based adult maintenance dog food

227 Apparent and true digestibility of minerals in animal and vegetable ingredient based adult maintenance dog food

Fish protein hydrolysate in diets for Nile tilapia post-larvae

Abstract: The objective of this work was to determine the apparent digestibility coefficient (ADC) of crude protein, crude energy, fat, and dry matter of fish protein hydrolysate (FPH), made of by-products of Nile tilapia (Oreochromis niloticus) and whole sardines (Cetengraulis edentulus), and to evaluate the productive performance and muscle fiber growth of Nile tilapia post-larvae. Two trials were conducted, the first one to determine the digestibility in 120 fingerlings (70.0±2.0 g), and the second one to evaluate the productive performance of 375 post-larvae, with three days of age, which were distributed in 25 aquaria with 30 L of useful volume. Five diets were prepared based on vegetable ingredients, to which fish were included at 0, 2, 4, 6, and 8% FPH. For the evaluation of muscle growth, eight fish of each experimental unit were used. The ADC values found were: 98.29% for dry matter; 99.28% for crude protein; and 99.13% for gross energy. The best zootechnical response for the productive performance resulted from the treatment with the inclusion of fish hydrolysate at 4.75%. The diets affected the frequency of the muscle fiber diameters, mainly the growth by hyperplasia. FPH can be efficiently used, and its inclusion at 4.75% is indicated in the diets for Nile tilapia in the post-larvae stage.

Desafios para utilização eficiente da fitase na nutrição de peixes

O ácido fítico (IP6) é o principal estoque de fósforo nas plantas e representa entre 50 e 80% do fósforo total presente nos ingredientes vegetais. Por ser indigestível pelos animais não ruminantes e permanecer carregado negativamente no pH fisiológico, liga-se a uma grande variedade de nutrientes, principalmente cátions, os quais são eliminados via fezes. Este fato torna necessária a suplementação de fósforo disponível o que aumenta os custos e problemas ambientais. Em vista disso, a fitase tem sido utilizada como forma de degradar a molécula de IP6 e aumentar o aproveitamento do fósforo indisponível. Esta enzima é usada com sucesso na alimentação de aves e suínos, porém controversa para peixes. Como toda enzima, a fitase possui uma faixa de temperatura e pH ótimos para atuar e desnatura quando submetida a extremos. Assim, o processamento da ração (extrusão) e as diversas condições anatômicas e fisiológicas das espécies de peixe desafiam sua integridade e atuação. Em vista disso, entender os principais aspectos envolvidos nos resultados obtidos com o uso da fitase na alimentação de peixes, conduz ao seu uso correto considerando as condições para sua atividade e os desafios impostos tanto pelo processamento quanto pela espécie de peixe.

Dietary effects of soybean products on gut microbiota and immunity of aquatic animals: A review

Soybean meal (SBM) is one of the most commonly used vegetable ingredient to replace fish meal in fish diets. However, SBM is limiting in some essential amino acids and contains numerous antinutritional factors and antigens that can affect intestinal microbiota and innate immune system in several finfish species and crustaceans and compromise health. The impact of SBM on health and gut microbiota of aquatic animals is not only affected by SBM in general, but also on the degree of treatment of the meal and exposure. Recently, many studies are actively seeking ways to complement or balance those adverse responses induced by high inclusion of SBM in aquaculture diets. These include advanced processing and mixture of feed with other feed components to balance antinutritional factors. The impact of dietary soybean oil on gut microbiota has also been investigated but to a lesser extent than SBM. As the gastrointestinal tract has been suggested as one of the major routes of infection in finfish species and crustaceans, the effect of soybean products on the gut microbiota is important to investigate. Several studies have focus on supplementation of SBM on the adverse responses of the innate immune system as immunological mechanisms are likely involved in the underlying pathology. However, the precise cause of the inflammatory process has not yet been clarified, even though some investigations have suggested that alcohol-soluble antinutritional factors, especially soy saponins, are potential causative factors. Possible interactions between soybean products and innate immune system in several finfish species and crustaceans are discussed.

Digestible energy requirement for females of Rhamdia quelen on reproductive activity fed with ration based on vegetal ingredients

The present experiment was carried out to evaluate the growth and reproductive parameters of Rhamdia quelen females fed with pelleted ration containing different levels of digestible energy, and to evaluate the vigor of their offspring. The breeders were placed in tanks under conditions of photoperiod and natural temperature. The fishes were fed for 255 days with isoproteic rations pelleted containing 35% of crude protein (CP) and five levels of the digestible energy (DE) (2700, 2950, 3200, 3450, 3700 kcal kg-1). The fishes were distributed in a randomized experimental design compounded by five treatments and three repetitions. A 16-m2 tank containing six females and three males was considered as one experimental unit. The weight and weight gain was evaluated. During the reproductive season the females were induced to breeding by hormonal manipulation and were evaluated the percentage of spawning females, the total fecundity, relative fecundity (number of oocytes per gram of spawning females), the fertilization ratio, the time to hatching and the vigor of larvae. The growth and reproductive parameters were not influenced (P > 0.05) by the increasing levels of digestible energy of the rations. The feeding of R. quelen females in breeding fit can be carried out with 2700 kcal kg-1 pelletized ration based on vegetal ingredients, without damage to reproductive performance.

Uptake of benzo[a]pyrene, but not of phenanthrene, is inhibited by fatty acids in intestinal brush border membrane vesicles of rainbow trout (Oncorhynchus mykiss)

Partial replacement of fish ingredients with vegetable ingredients has elevated levels of polycyclic aromatic hydrocarbons (PAHs) in Atlantic salmon reared on these feeds. PAH uptake in the intestinal tract is postulated to occur in association with lipid absorption and could well be affected by fatty acid composition. We therefore investigated the effects of a fish oil and vegetable oil fatty acid, eicosapentaenoic acid (EPA; 20:5n−3) and oleic acid (18:1n−9) respectively, on the uptake of benzo[a]pyrene (BaP) and phenanthrene (PHE) across the intestinal brush border membrane in the salmonid species rainbow trout (Oncorhynchus mykiss).BaP and PHE were solubilized in mixed micelles composed of either EPA or oleic acid and administrated to isolated brush border membrane vesicles (BBMV) derived from the pyloric caeca, proximal intestine and distal intestine. In the absence of free fatty acids (FFA) trans-membrane uptake of BaP and PHE was 2–7 times lower than the fraction associated to or in the membrane. In the presence of FFA, trans-membrane BaP uptake had decreased by 80 and 40% at the highest EPA and oleic acid concentration, respectively, whereas PHE uptake was virtually unaffected. In the presence of BaP, but not PHE, trans-membrane EPA uptake in BBMV had decreased.This study obtained evidence for PAH-dependent interactions with FFA uptake. We conclude that intestinal BaP uptake is reduced by luminal FFA contents whereas PHE uptake is not. A large fraction of the administrated BaP and PHE remains associated with the cellular membrane of enterocytes and may interfere with uptake of nutrients.

Application of formulated diets and their effects on nutrient digestibility and reproductive performance of female mink (Neovison vison) during gestation

ABSTRACTThis study was designed to investigate the possibility of total replacement of conventional diet by formulated experimental feed in farmed mink during gestation. Ninety female mink (Neovison vison) were randomly assigned to three groups: control group was fed conventional diet with normal (36%, C) protein level composed of fresh or frozen animal by-products and extruded corn. Formulated experimental diets contained animal meals, vegetable ingredients and fat, with normal (36%, E1) or high (44%, E2) protein level, and were mixed with water prior to administration. Nutrient digestibility, nitrogen (N)-balance and reproductive performance were determined to compare the effect of diets fed to female mink during gestation. Mink fed both experimental diets had lower nutrient digestibility than the control. Higher barren females, decreased birth survival rate and birth weight were noted for the two experimental groups, especially diet E1 with normal dietary protein, indicating impaired reproduction performance, but signs of improvement were seen in the experimental group with high protein level (44%, E2).

Formulation and evaluation of a water-in-oil cream containing herbal active ingredients and ferulic acid.

Background and aimsThe main aims of the present study were to formulate an anti-age cream based on vegetal ingredients and ferulic acid and to evaluate the physical characteristics and the efficacy of the cream.MethodsThe active ingredients were Centella asiatica oil, Spilanthes acmella oil, Zingiber officinale extract and ferulic acid. Formulation 1 (F1) was prepared using glyceryl stearate and Ceteareth-25® as emulsifiers and Formulation 2 (F2) using glyceryl stearate and potassium cetyl phosphate, all other ingredients remaining the same. The physical characterization of the creams was performed and the following parameters were analyzed: viscosity, oil droplet size, polydispersity index; also, texture analysis was performed. The anti-aging effect of the F2 was evaluated by assessing the cutaneous density before and after cream application using DUB-cutis® scanner.ResultsThe mean diameter of oil drops was 10.26±4.72 mm (F1) and 22.72±7.93 mm (F2) and the polydispersity index was 35.4% and 45.7%, respectively. The mean values for consistency were 594.7±10.3 g (F1) and 300.5±14.5 g (F2), the average values for adhesion were 15.61±0.8 mJ (F1) and 22.25±4.3 mJ (F2), for firmness were 51.2±0.8 g (F1) and 30.3±4.3 g (F2) and the spreadability had values between 72.63 mm2 (F1) and 73.3 mm2 (F2). In vivo study revealed that the mean values of the cutaneous density increased from 9.21±1.39 % to 12.50±1.44 % after 8 weeks of cream application. The herbal ingredients incorporated in the O/W cream base for the antioxidant activity and anti-wrinkle effect, induced changes of the cutaneous density, an important parameter which quantifies the regeneration process of the skin.ConclusionsAn anti-age cream containing herbal active ingredients and ferulic acid with appropriate physical characteristics was obtained. In vivo study of clinical efficacy revealed a positive effect on skin density, which increased after 8 weeks of cream application.

Use of near infrared reflectance spectroscopy to predict phytate phosphorus, total phosphorus, and crude protein of common poultry feed ingredients

The purpose of the study that is presented herein was to develop near-infrared reflectance spectroscopy (NIRS) calibrations to predict total phosphorus (P), phytate-P, and protein concentrations of feed ingredients commonly used in monogastric feed formulation. Samples representing 14 vegetable ingredients (cereals, cereal by-products, and oilseed meals) were collected worldwide throughout 2013. The samples were assayed by standard wet chemical techniques for total P, phytate-P, and protein content. There was substantial variability in protein, phytate-P, and total P within and between ingredients used in the calibration set. Protein content varied from 76 to 487 g/kg. Total P ranged from 2.09 and 22.5 g/kg and phytate-P ranged from 0.99 and 13.8 g/kg. Within these broad ranges, NIRS values were highly correlated for determination of protein, total P, and phytate-P with a standard error of prediction equal to 9.06 g/kg, 0.80 g/kg, and 0.66 g/kg, respectively. The wide diversity and heterogeneity of the mix of feed ingredients allowed the development of NIRS calibrations of sufficient accuracy to help nutritionists control the nutritional composition of their feed.

<b>Effect of phytase on digestibility of corn, sorghum and wheat bran by silver catfish (<i>Rhamdia voulezi</i>)

This study aimed to evaluate the digestibility of plant energetic ingredients, corn, sorghum and wheat bran, with and without phytase supplementation, in silver catfish (Rhamdia voulezi). The experimental design was completely randomized, represented by eight treatments, which consisted of the development of a reference diet and a test diet for each ingredient evaluated (corn, sorghum and wheat bran), with and without supplemental phytase. Diets were formulated so as to contain 70% reference feed and 30% test ingredient. The digestibility coefficients of dry matter and crude protein were significantly influenced only in relation to the evaluated ingredients. Phytase influenced the digestibility coefficients of energy and phosphorus, with interaction between food and the enzyme addition. The interaction between these two factors shows that the phytase efficiency is dependent on the type of vegetable ingredient used in the diet. The results suggest the supplementation of phytase for a higher nutrient digestibility of corn, sorghum and wheat bran by silver catifish (R. voulezi).

Digestibility of animal and vegetable protein ingredients by pirarucu juveniles, Arapaima gigas

The objective of this study was to determine the apparent digestibility coefficients of energy, protein, and amino acids in protein ingredients by pirarucu juveniles. A test was conducted with six protein ingredients: meat and bone meal, fish meal, hydrolyzed feather meal, poultry by-product meal, soybean meal, and corn gluten meal. Three repetitions were used for each tested ingredient. A reference feed was used with 430 g kg−1 crude protein and 19.63 kJ g−1 gross energy. The test feeds consisted of the replacement of 30% of the reference feeds with the test ingredients. Chromium oxide was added to the feeds at 1 g kg−1 as an external marker. Eighteen juveniles with an average weight of 235±36 g were used. The best apparent digestibility coefficients of protein were found for fish meal, followed by the poultry by-product meal and meat and bone meal. However, except for gluten, all the tested ingredients presented protein digestibilities above 0.70. The crude energy apparent digestibility coefficient was higher for animal ingredients, above 0.75, than for vegetable ingredients, which presented values below 0.60. Pirarucu efficiently uses the protein from the tested ingredients, regardless of origin. However, it has a preferential ability to use the energy from animal ingredients.

COEFFICIENTS OF ENERGY AND NUTRIENT APPARENT DIGESTIBILITY OF THREE RAW AND COOKED ALTERNATIVE PLANT INGREDIENTS FOR Colossoma macropomum AND Piaractus brachypomus (SERRASALMIDAE)

The coefficients of the apparent digestibility for dry matter, crude protein, crude lipid and gross energy in cooked and raw green plantain meal (GPM), cassava root meal (CRM), and peach palm meal (PPM) were determined for juveniles of black pacu (60.8 ± 6.4 g) and red pacu (76.3 ± 5.0 g). The ADC of each alternative ingredient was determined by comparison of the digestibility (based on recovery of 1% chromic oxide as an inert marker) of a reference diet (consisting of 70% of test diet and 30% of the feedstuff) against with a test diet (24.5% of crude protein). Fish were bred in a recirculation system including 42, 110-L glass aquaria (21 tanks per species) at a density of five fish per tank, and fed their respective diets to apparent satiety, twice a day. Feces were collected after 10 days in plexiglass fecal collectors. Apparent digestibility coefficients of crude protein, crude lipid and gross energy from raw and cooked GPM and CRM were low compared to values to other common vegetal ingredients like corn and wheat. Conversely, ADC values for raw and cooked PPM were, in most cases, higher than those reported in raw or cooked GPM and CRM. In comparison with other traditional feedstuffs, apparent utilization of PPM was similar to corn and higher than reported for soybean meal and wheat bran in these fish species. Peach palm meal appears to have good potential as a feed ingredient in low-cost diets for pacu species.

Modelling scenarios on feed-to-fillet transfer of dioxins and dioxin-like PCBs in future feeds to farmed Atlantic salmon (Salmo salar)

The salmon feed composition has changed the last decade with a replacement of traditionally use of fish oil and fishmeal diets with vegetable ingredients and the use decontaminated fish oils, causing reduced concentrations of dioxins and dioxin-like PCBs in farmed Norwegian Atlantic salmon. The development of novel salmon feeds has prompted the need for prediction on dioxins and dl-PCB concentrations in future farmed salmon. Prediction on fillet dioxins and dl-PCB concentrations from different feed composition scenarios are made using a simple one-compartmental transfer model based on earlier established dioxin and dl-PCB congener specific uptake and elimination kinetics rates. The model is validated with two independent feeding trials, with a significant linear correlation (r2 = 0.96, y = 1.0x, p < 0.0001, n = 116) between observed and predicted values. Model fillet predictions are made for the following four scenarios; (1) general feed composition of 1999, (2) feed composition of 2013, (3) future feed composition with high fish oil and meal replacement, (4) future feed composition with high fish oil and meal replacement and decontaminated fish oil. Model predictions of fillet dioxin and dl-PCB concentrations from 1999 (1.05 ng WHO2005-TEQs kg−1ww) and 2013 (0.57 ng WHO2005-TEQs kg−1ww) are in line with the data observed in national surveillance programs of those years (1.1 and 0.52 ng WHO2005-TEQs kg−1ww, respectively). Future use of high replacement and decontaminated oils feeds gave predicted fillet concentrations of 0.27 ng WHO2005-TEQs kg−1ww, which is near the limit of quantification.

Protein structural changes during processing of vegetable feed ingredients used in swine diets: implications for nutritional value.

Protein structure influences the accessibility of enzymes for digestion. The proportion of intramolecular β-sheets in the secondary structure of native proteins has been related to a decrease in protein digestibility. Changes to proteins that can be considered positive (for example, denaturation and random coil formation) or negative (for example, aggregation and Maillard reactions) for protein digestibility can occur simultaneously during processing. The final result of these changes on digestibility seems to be a counterbalance of the occurrence of each phenomenon. Occurrence of each phenomenon depends on the conditions applied, but also on the source and type of the protein that is processed. The correlation between denaturation enthalpy after processing and protein digestibility seems to be dependent on the protein source. Heat seems to be the processing parameter with the largest influence on changes in the structure of proteins. The effect of moisture is usually limited to the simultaneous application of heat, but increasing level of moisture during processing usually increases structural changes in proteins. The effect of shear on protein structure is commonly studied using extrusion, although the multifactorial essence of this technology does not allow disentanglement of the separate effects of each processing parameter (for example, heat, shear, moisture). Although most of the available literature on the processing of feed ingredients reports effects on protein digestibility, the mechanisms that explain these effects are usually lacking. Clarifying these mechanisms could aid in the prediction of the nutritional consequences of processing conditions.

Digestibility of vegetal energetic ingredients supplemented with phytase for silver catfish (Rhamdia voulezi)

The aim of this study was to evaluate the digestibility of nutrients in oats, rice grits and wheat middlings by the silver catfish (Rhamdia voulezi), with and without phytase. Two hundred eighty-eight fish were distributed in 24 tanks of 500L with tapered conical bottoms. The experimental design was completely randomized, represented by eight treatments and three replications. The treatments consisted of the development of eight diets (reference with and without phytase, oats with or without phytase, rice grits with or without phytase and wheat middlings with or without phytase) in a factorial scheme. The diets using the ingredients were composed of 70% of the reference diet and 30% of the ingredient. In the supplemented diets, we used 1500FTUKg−1 of phytase. We performed physico-chemical and mineral analyses of the ingredients, diets and feces and performed the reading of chromium oxide in the diets and feces. The supplement of 1500FTUKg−1 in the diet improves the coefficients of nutrient digestibility, mainly for oats and rice grits. Considering the feeds supplemented or not with 1500FTUKg−1 in the diet, the rice grits and wheat middlings have higher values of use of their nutrients and can be used more efficiently in feeding catfish (R. voulezi).

The effect of dietary lipid composition on the intestinal uptake and tissue distribution of benzo[a]pyrene and phenanthrene in Atlantic salmon (Salmo salar)

Uptake of polycyclic aromatic hydrocarbons (PAHs) across the intestine is suggested to occur in association with dietary lipids. Partial replacement of fish ingredients by vegetable ingredients in aquafeeds has led to increased levels of PAHs in marine farmed fish. We therefore investigated, intestinal uptake, tissue distribution and PAH metabolism after a single dose of 14C-benzo[a]pyrene (BaP) or 14C-phenanthrene (PHE) given to Atlantic salmon (Salmo salar) acclimatized to a fish oil or vegetable oil based diet. Both BaP and PHE were absorbed along the intestine. Fish oil based feed increased BaP concentration in the pyloric caeca and that of PHE in the proximal intestine. In contrast, vegetable oil increased BaP concentrations in the distal intestine. Extraction of whole body autoradiograms removed PHE-associated radiolabeling almost completely from the intestinal mucosa, but not BaP-associated radiolabeling, indicating the presence of BaP metabolites bound to cellular macromolecules. This observation correlates with the increased cyp1a expression in the proximal intestine, distal intestine and liver in the BaP exposed group. Furthermore, BaP-induced cyp1a expression was higher in the distal intestine of salmon fed fish oil compared to the vegetable oil fed group. PHE had no significant effect on cyp1a expression in any of these tissues.We conclude that dietary lipid composition affects intestinal PAH uptake. Fish oil based feed increased intestinal PAH concentrations probably due to an enhanced solubility in micelles composed of fish oil fatty acids. Increased BaP accumulation in the distal intestine of vegetable oil fed fish seems to be associated with a reduced Cyp1a-mediated BaP metabolism.

Sustainability vs. Quality in gilthead seabream (Sparus aurata L.) farming: are trade‐offs inevitable?

AbstractEuropean aquaculture industry should be at the forefront of sustainable development, providing healthy and safe food of the highest quality to the consumer, through an environmentally sound approach. The purpose of this review was to explore in what way the current drive for sustainability has affected what the consumer perceives as quality in fish, specifically in gilthead seabream, one of the most important farmed species in the Mediterranean. It focuses on nutritional aspects such as fish meal and fish oil replacement, quality tailoring through finishing strategies, the influence of different farming systems and the effect of slaughter stress on seabream quality. In general, fish meal and fish oil replacement with vegetable ingredients will result in changes in the fatty acid profile of the fillets, and consequently the potential health benefits seabream offers to the consumer. While organoleptic properties suffer little change, the impact of these ingredients on welfare has not been fully investigated. Further studies are also needed to evaluate the effect of land animal ingredients on seabream quality. In either case, although finishing strategies to restore essential fatty acids are not completely effective, seabream can still retain a high nutritional value. Information on the use of dietary supplements as finishing strategies is still extremely scarce. Regarding fish welfare, the high densities practised in intensive production systems pose concerns which warrant further research in this area. Furthermore, new alternatives for common harvesting and slaughter methods are needed to improve welfare, as traditional methods are clearly stressful.

Formulation of Nutritionally Superior and Low Cost Seaweed Based Soup Mix Powder

The demand for dried instant soups is increasing to their ease of use. In particular, the boom in healthy and functional foods, there is general preference for healthy soup prepared using vegetables, legumes, cereals and mushrooms. Dried instant soup has long shelf life because it is a dried food and frequently has its effective tasting time period set for a relatively long time. This study was conducted to develop a nutritious instant vegetable soup mixture incorporated with cereals, legumes and seaweed extracts such as agar or carrageenan use and was to replace of pectin. The agar and carrageenan area industrial food substitute enrich with protein, minerals, vitamins and amino acid which improve the overall nutritive values and viscosity of the soup. Organoleptic evaluation was conducted to select best combination of ingredients of vegetables, cereals, legumes and preservatives. In addition to that Ulva powder and seaweed extracts (agar or carrageenan) were incorporated in different percentages and was evaluated for the sensory attributes to optimize and compare physical chemical and sensory parameters with commercial vegetable soup mixture. The data rank some test revealed that best soup mixture were evaluated by sensory attributes one commercial available and two formulated soup mixtures with contain 80% vegetables, 10% grain, 3.5% legumes, 2.5% dried Ulva powder with 3% agar agar or 2% carrageenan and preservatives. The soup formulas have highest viscosity (698 cps, 766 cps, 951cps), water activity (0.618, 0.586, 0.437), crude protein (9.3%, 7.2%, 1.7%), carbohydrate (64.54%, 61.3%, 51.32%), iodine value and (0.35, 0.32, 0 mg/l) respectively in agaragar incorporated soup, carrageenan incorporated soup and commercial vegetable soup mixture. The total bacterial counts, total fungal counts and water activity were at the acceptable levels for consumption. The low levels of yeast and mould counts were detected in all the samples during the storage period. This two formulated products can be introduced to the commercial market as alternative medicinal heath food.

Study of microbiological background of herbal ingredients and dairy-vegetable compositions

The rates of microbiological safety of powdery vegetables, vegetable-milk compositions, compound desserts have been studied. No pathogenic germs (incl. salmonella), Escherichia coli, yeast, nonspore-forming bacteria B cereus have been detected in powdery vegetable samples. The number of mesophilic aerobic and facultative anaerobic microorganisms as well as amount of molds does not exceed safety index normalized by the legislation. Proteolytic microorganisms compose the basic microflora of powdery vegetables. Microbiological background of vegetable and milk basis is characterized by the presence of microorganisms differed by different resistance to the medium conditions – рН value, presence of oxygen and high temperatures impact. Enrichment of milk base by vegetable components necessitates to adjust the thermal effect regimes prescribed for milk treatment without additional ingredients. Introduction of vegetable ingredients into milk base is accompanied by polysemantic effect of high temperatures on microorganisms of polycomponent milk – vegetable base. On the one hand introduction of vegetable raw material into milk enhances inhibitory temperature effect on microbial cells due to transition of the medium рН into sour side; on the other hand presence of vegetable raw material particles protects microorganisms against sensitive effect of high temperature. Microflora of vegetable-milk compositions after heat treatment as well as ready-made desserts on their base was presented by spore-forming bacillus the number of which is correlated by their number in the initial raw material. In order to choose the optimal regime of heat treatment all processes running during heat treatment and particularly microbiological and physical-chemical degradation of polysaccharides of vegetables cell structures.

Impact of Fishmeal Replacement in Diets for Gilthead Sea Bream (Sparus aurata) on the Gastrointestinal Microbiota Determined by Pyrosequencing the 16S rRNA Gene.

Recent studies have demonstrated the impact of diet on microbiota composition, but the essential need for the optimization of production rates and costs forces farms and aquaculture production to carry out continuous dietary tests. In order to understand the effect of total fishmeal replacement by vegetable-based feed in the sea bream (Sparus aurata), the microbial composition of the stomach, foregut, midgut and hindgut was analysed using high-throughput 16S rDNA sequencing, also considering parameters of growth, survival and nutrient utilisation indices.A total of 91,539 16S rRNA filtered-sequences were analysed, with an average number of 3661.56 taxonomically assigned, high-quality sequences per sample. The dominant phyla throughout the whole gastrointestinal tract were Actinobacteria, Protebacteria and Firmicutes. A lower diversity in the stomach in comparison to the other intestinal sections was observed. The microbial composition of the Recirculating Aquaculture System was totally different to that of the sea bream gastrointestinal tract. Total fishmeal replacement had an important impact on microbial profiles but not on diversity. Streptococcus (p-value: 0.043) and Photobacterium (p-value: 0.025) were highly represented in fish fed with fishmeal and vegetable-meal diets, respectively. In the stomach samples with the vegetable diet, reads of chloroplasts and mitochondria from vegetable dietary ingredients were rather abundant. Principal Coordinate Analysis showed a clear differentiation between diets in the microbiota present in the gut, supporting the presence of specific bacterial consortia associated with the diet.Although differences in growth and nutritive parameters were not observed, a negative effect of the vegetable diet on the survival rate was determined. Further studies are required to shed more light on the relationship between the immune system and sea bream gastrointestinal tract microbiota and should consider the modulation of the microbiota to improve the survival rate and nutritive efficacy when using plant-based diets.