Common carp (Cyprinus carpio L.) is a dominant fish species in aquaculture, and as it is a stomachless species, absorption and digestion of nutrients take place in the intestine. The aim of the study was to evaluate the effects of a prebiotic on the content of selected minerals found in the meat, gills, and skeleton of common carp. The research applied trans-galactooligosaccharide (GOS) prebiotic produced by enzymatic transgalactosylation of milk lactose by whole cells of Bifidobacterium bifidum. The following diets have been applied: control diet without feed additives (C), diet 2 (B1) with 1% of GOS, and diet 3 (B2) with 2% of GOS. In the freeze-dried samples, concentrations of the analyzed metals were determined using atomic absorption spectroscopy (AAS). The content of phosphorus was determined using colorimetric method. The analyses confirmed that the highest level of Mg was detected in the skeleton of fish fed with 1% GOS (2.51 g kg−1) and was significantly higher compared the control treatment (2.11 g kg−1) (P < 0.05). Zn content in fish meat fed with 1% GOS (35.41 mg kg−1) was significantly higher (P < 0.05) than in the control group (24.59 mg kg−1). The tissue that accumulated the greatest amount of Zn was the gills. GOS had a positive effect on Fe accumulation in the meat, gills, and skeleton. It has been concluded that supplementation of feed with 2% GOS significantly influenced the positive correlations between Mg and P in the meat and skeleton, Fe–Ca correlation in gills, and Fe–Zn correlation in the skeleton.
Fish is one of the most valuable food sources of minerals, the concentration of which is influenced by many endogenous and exogenous factors. There are many factors present in the feed that can inhibit the absorption of minerals, e.g., phytates, fibers, and heavy metals [1,2,3]. Moreover, the degree of mineral absorption is influenced by the physicochemical properties of water, such as hardness, salinity, and pH [3, 4]. Changes in the dietary composition and mineral concentration of rearing water could have an impact on the mineral balance in fish tissues and proper physiological state of animals. One of the most serious health and economic problems in the world of marine and freshwater aquaculture is the fish body deformation [5, 6]. Initially, deformations of the food-based skeleton were explained by the vitamin C deficiency in diet, yet currently the main cause of these deformations has been attributed to the deficiency of minerals . A research has confirmed that the presence and proper balance between Ca, P, Mg and Zn are necessary for the correct mineralization of the fish skeleton [3, 6, 7]. Moreover, since excessive Fe intake inhibits Zn absorption (antagonistic effect), analyzing Fe levels should also be considered.
Common carp (Cyprinus carpio L.) has been a dominant fish species in the world aquaculture production  and was the first species introduced into Polish aquaculture. The first records on farming date back to the twelfth century, and after the year 1550, common carp accounted for about 75–80% of all fish farmed in ponds. Poland and the Czech Republic are the largest producers of common carp in the European Union, and the annual production of consumable common carp in Poland ranges between 15 and 23,000 t [9, 10]. Common carp is an omnivorous species with low nutritional requirements, both in terms of the feed composition and its production technology. In addition, common carp farmed in ponds largely relies on a natural diet which usually consists of the biomass produced by the pond. Carp does not have functional stomach, and digestion takes place in the intestine hence from digestibility food, and assimilation is limited. Due to the fact that the cyprinids do not have acid-secreting stomachs, the mineral absorption from organic compounds (in particular phosphorus) may be reduced [11, 12].
In recent years, the influence of various factors on the degree of fish mineralization has been studied such as different starter diets or water temperature [6, 13,14,15]. To our knowledge, there is little data available on the effect of prebiotics on the accumulation of minerals in different tissues of common carp. As confirmed by research prebiotics (e.g., fructooligosaccharides (FOS), transgalactooligosaccharides (t-GOS), inulin, and mannanooligosaccharides (MOS)) have a positive effect on the gut microbiota composition. They inhibit the growth of pathogenic gut microbial flora while stimulating the growth of microorganisms beneficial for the animal host. Beneficial gut bacteria can improve the body’s natural defenses, synthesize vitamins, and bind toxins and heavy metals. In aquaculture, prebiotics are increasingly used due to their positive effect on growth stimulation, use of feed, gut microflora, gut morphology, immune system, and disease resistance [8, 16,17,18,19,20,21,22,23]. These bioactive substances play an important role in regulating mineral metabolism, mineral bioavailability, and bone health [23,24,25,26,27]. Moreover, prebiotics affect the production of short-chain fatty acids, lowering the intestinal pH, regulating the factors responsible for the transport of divalent metals, thanks to which they improve the absorption of metals and skeletal health [28,29,30,31,32]. Some authors confirmed, that prebiotics and their products of fermentation by intestinal microflora have an enhancing effect on Fe and Zn absorption [23, 24, 33, 34]. Therefore, it definitely seemed valid to analyze the degree of absorption of minerals by carp family member (representatives of the Cyprinidae family) under prebiotic supplementation.
The prebiotic used in this experiment, under the trade name Bi2tos, is manufactured by Clasado (Biosciences Ltd., Jersey, UK) by enzymatic transgalactosylation of milk lactose by whole cells of Bifidobacterium bifidum 41171. For this reason, Bi2tos specifically promotes growth of Bifidobacterium spp. . Our previous research revealed that the supplementation of feed with 1% and 2% Bi2tos significantly enhanced the development of the intestine, increased the height and width of the villi, and increased their surface area , which may contribute to increased absorption of nutrients from the gut.
The aim of the present study was to analyze the effects of dietary supplementation of a trans-galactooligosaccharide (GOS) on the content of selected minerals in the meat, gills, and skeleton of common carp and on the correlations between minerals analyzed.
Material and Methods
Studies on live animals were carried out in strict accordance with the recommendations of the National Ethics Commission (Warsaw, Poland). All members of the research staff were trained in animal care, handling, and euthanasia. Fish health and welfare and the environmental conditions in the experimental tanks were checked twice daily by visual observation of animal behavior and by checking water quality parameters, such as oxygen saturation, temperature, and water flow. After sedation, the animals were decapitated according to the American Veterinary Medical Association Guidelines for the Euthanasia of Animals . According to Polish law and an EU directive (no 2010/63/EU) , the experiments conducted in this study did not require approval from the Local Ethical Committee for Experiments on Animals in Poznań.
The experimental diets were calculated as isonitrogenous (35.1% crude protein) and isoenergetic (18.5 MJ kg−1) with less than 4% of crude fiber and were formulated according to common carp nutritional requirements [39,40,41]. Three experimental diets were used: control diet 1 (C) without feed additives, diet 2 with 1% of GOS (B1), and diet 3 (B2) with 2% of GOS (Table 1).
The experimental diets were prepared according to the following procedures below:
Preparation of components of the diets: individual components weighed out; ground in a percussion mill until very fine (mesh size 1 mm).
Preparation of the premix: vitamin and mineral components, soybean lecithin, choline chloride, chalk, and prebiotic were added to the carrier (soybean meal); mixed for 5 min in a cubic mixer.
Preparation of the diets: all ingredients and the premix mixed in a drum mixer for 5 min.
Conditioning the diets: hot water added; mixed in blade mixer for 5 min.
Extrusion: Metalchem S-60 single screw warm extruder (Gliwice, Poland), the extrusion conditions were as follows: a 90 °C cylinder temperature in the zone of increasing pressure, a 100 °C cylinder temperature in the zone of high pressure, a 110 °C head temperature, a 52-rpm speed screw, and a 6-mm nozzle diameter.
Drying: on mesh under a stream of heated air.
Sifting: the dust fraction sifted off in a percussion sifter.
Oiling: fish oil heated to 50 °C in quantities of 4.6% was used to coat extruded diet in a pelletizing drum.
Final sifting: the dust fraction sifted off in a percussion sifter.
Prepared feeds have been packed in foil bags and stored minus 18 °C until use.
The 60-day growth trial was carried out in the Experimental Station for Feed Production Technology and Aquaculture in Muchocin (Poland). Three hundred one-year-old common carp (mean body weight 180 g) were used. The fish were randomly stocked into 12 concrete ponds (40 m3), at a density of 25 fish per pond according to Horváth et al. . The experiment was carried out in four replications (four ponds per treatment). Each pond was equipped with an automatic band feeder allowing for the continuous supply of feed during 12 h per day. The calculated daily feed dose for each pond was given every day at 9.00 a.m., its consumption was controlled visually twice a day, and rate was corrected if needed. The daily feed dose was restricted to assure that all feed supplied was consumed. The feeding rate was calculated in consideration of fish biomass in each pond which was corrected every 10 days on the basis of control bulk weighing of all fish; measurements of the current average daily water temperature and feed consumption from previous day were used for the additional correction according to Miyatake’s  recommendations, which resulted in feeding rate ranging from 1.8 to 3.3% of fish biomass. A constant flow of water in the experimental system was ensured by an open flow system with a mechanical pre-filtration chamber providing total exchange of water capacity in each pond every 12 h. During the experimental period, control of water physio-chemical parameters was carried out with the use of microcomputer oximeter Elmetron CO-315. Average daily water temperature and pH were studied which ranged from 17.7 °C to 22.7 °C and 7.2 to 7.6, respectively. Dissolved oxygen was kept above 3.5 mg O2/L, and hypoxia conditions were not observed in the experiment (details are described in Ziółkowska et al. ).
During the experiment, fish were anesthetized by immersion in 130 mg/L tricaine methanesulfonate (MS–222, Sigma Aldrich) for weighing at 10-day intervals for feed rate control. Body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR), specific growth rate (SGR), protein efficiency ratio (PER), and percentage weight gain (PWG) were calculated (details are described in Ziółkowska et al. ).
At the end of the experiment, four fish per pond were euthanized by immersion in 500 mg L−1 of MS–222  for tissue sampling for metals analysis. The number of individuals subjected to analyses was based on earlier studies performed by Hoffman et al.  and Józefiak et al.  to provide a necessary sample size for laboratory and statistical analysis, and to avoid unnecessary animal sacrificing (according to 4R policy).
The meat samples for analyses were taken from the large side muscle of fish body above the lateral line, the gills that was branchial arch with filaments, and the skeleton that was a spine with ribs. The meat, gills, and skeleton were crumbled and freeze-dried in Lyovac GT2 freeze-drier by Finn-Aqua (Finland) (parameters: temperature − 40 °C, pressure 6·10−2 mbar, duration at least 48 h).
Metal concentrations were determined in freeze-dried samples after aqua regia digestion (ISO 11466:1995) using atomic absorption spectroscopy (AAS) with a SOLAR S4 spectrophotometer. Phosphorus content was analyzed with colorimetric method (ISO 13730:1996), by spectrophotometer Lambda 25, Perkin-Elmer (at wavelength 430 nm). The concentrations of the metals were calculated from linear calibration plots obtained from measurements of the working standard solutions. Certified AAS Merck standard solutions were used for the calibration of the standard curves, and validation was conducted on Certified Reference Material Fish Muscle ERM®-BB422 and Certified Reference Material Aquatic Plant BCR®-670. All determinations were made in triplicate, and the data for samples of the meat were corrected to oven-dry (105 °C) moisture content. Tissue concentrations of the metals were given in mg kg−1 dry weight (mg kg−1 d.w.) for Zn and Fe and g kg−1 dry weight (g kg−1 d.w.) for Mg, Ca, and P. Minerals analyses were conducted at UTP University of Science and Technology in Bydgoszcz (Poland).
Statistical calculations were made using Statistica 13.0 software (StatSoft 13.0). The arithmetic mean (x) and standard deviation (SD) were calculated. Four fish per pond (n = 16; 16 fish for each treatment) were collected for minerals analyses. Significant differences between the groups were tested with one-way analysis of variance (ANOVA), and Tukey’s test was used for multiple comparisons. The normality of the data was tested using the Shapiro-Wilk’s test and the homogeneity of variance was verified by means of the Levene’s test. The level of significance was determined at P ≤ 0.05. Interrelationships between analyzed minerals in the individual tissues were determined based on the Pearson’s correlation coefficients.
Concentrations of Minerals
The results of the present study showed that Ca, Mg, and P concentration increased in tissues in the following order: meat < gills < skeleton. Zn and Fe concentration increased in the following order: meat < skeleton < gills (Figs. 1, 2, 3, 4, and 5). Analyses confirmed no statistically significant differences in Ca and P content between fish fed 1 and 2% GOS compared control treatment (0% GOS) for each tissue (Figs. 1 and 2). Ca/P ratio in the meat was 0.83, in the gills 4.65, and in the skeleton 2.13. The analyses confirmed that the value of this coefficient in the skeleton was significantly higher in B1 (2.25) and B2 (2.22) groups compared to the control (1.91). The highest level of Mg was detected in the skeleton of fish fed 1% GOS (2.51 g kg−1 d.w.), and was significantly higher compared control treatment (0% GOS) (2.11 g kg−1 d.w.), but this result was similar to the value determined for fish fed 1% GOS (2.34 g kg−1). There were no statistically significant differences in Mg content between the experimental groups, both in the case of the meat and the gills (Fig. 3). The results of the present study showed that Zn contents in fish fed 1% GOS (31.21 mg kg−1 d.w.) and 2% GOS (35.41 mg kg−1 d.w.) were significantly higher than control group (24.59 mg kg−1) (Fig. 4). Furthermore, it was found that enhancing feed GOS significantly affect the decrease in the Zn concentration in the skeleton. As our analyses of carp indicated, GOS addition caused statistically significant differences in Fe level between the experimental groups within all tissues (Fig. 5). Higher level of Fe was in the meat of fish fed 2% GOS (290.32 mg kg−1 d.w.) in comparison with control group (94.86 mg kg−1 d.w.) and fish fed 1% GOS (111.33 mg kg−1 d.w.). The concentration of this metal in the gills was in the range from 524.02 mg kg−1 d.w. (C group) to 586.52 mg kg−1 d.w. (B2 group), and these values differed significantly. Fe content in the skeleton differed significantly between the C group (172.85 mg kg−1 d.w.), B1 group (372.4 mg kg−1 d.w.), and B2 group (447.89 mg kg−1 d.w.).
Correlations Between Minerals
Statistically significant correlation coefficients between Fe–Ca (r = 0.997867; P < 0.05) in the gills and Fe–Zn (r = 0.997237; P < 0.05) in the skeleton were observed in B2 group. Also, positive correlation coefficients between Mg-P in the meat (r = 0.999855; P < 0.05) and in the skeleton (r = 0.995238; P < 0.05) were calculated in B2 group (Table 2).
Calcium (Ca) is one of the most abundant cations in the fish body and affects the structure of the skeletal system and maintaining a proper acid-base balance. Absorption of Ca from the gastrointestinal tract is controlled by hormones such as parathyroid hormones (PTH), calcitonin, and 1,25-dihydroxycholecalciferol . As confirmed by research, muscle tissue is not the main site of Ca accumulation in fish as opposed to the fish scales, bones, and skin [3, 47]. Our results on Ca accumulation in various tissues of common carp were in agreement with Brucka-Jastrzębska et al.  and Łuczyńska et al. . Numerous studies have confirmed that prebiotics such as oligofructose, inulin, galactooligosaccharides, resistant starches, and lactulose effectively stimulate Ca absorption [2, 50]. It has been hypothesized that short-chain fatty acids (SCFA), acetate, propionate, and butyrate, and other organic acids (e.g., lactate) produced by prebiotics lower the pH of light in the large intestine, which is associated with an increased amount of soluble Ca, especially in the caecum . Studies have shown that the effect of the prebiotic on Ca absorption depends on the content of this mineral in the diet. Effect of GOS on Ca absorption was more effective when dietary Ca was higher than the recommended level [50, 51]. Our analyses showed no statistically significant differences in Ca content between fish fed 1 and 2% GOS compared control treatment (0% GOS) for each tissue. Therefore, further research is necessary to analyze the effect of different amounts of Ca in the diet on the effectiveness of the prebiotic activity on Ca absorption. Ortiz et al.  determined that content of Ca in the fillet of rainbow trout (Oncorhynchus mykiss) was not affected by prebiotic supplementation at inclusion level of 5 g kg−1 (FOS oligofructose BENEO P95; Beneo-Orafti Espanã SL, Barcelona, Spain). The lack of effect of the prebiotic on the absorption of Ca from the intestine may be due to the fact that the duration of the experiment was too short .
Magnesium (Mg) is a cofactor of almost 300 enzymes, and thus participates in the transformation of carbohydrates, proteins, lipids, and nucleic acids. This metal plays an important role in the transmission of information between muscles and nerves, and it inhibits the process of blood clotting, owing to which it prevents the formation of clots. Mg, like Ca and phosphorus (P), is necessary for bone mineralization and it accumulates in the greatest amounts in bones . Our results regarding the level of Mg accumulation in various tissues were in line with Brucka-Jastrzębska et al. , Brucka-Jastrzębska and Protasowicki , Brucka-Jastrzębska and Kawczuga , and Łuczyńska et al. . The results of the present study showed that the highest level of this mineral was detected in the skeleton of fish fed 1% GOS (2.51 g kg−1 d.w.), and was significantly higher compared control treatment (0% GOS) (2.11 g kg−1 d.w.). However, 2% GOS supplementation did not cause a significant increase in Mg content. As Guerreiro et al.  confirmed, it is possible that fish gut bacteria community and digestive enzymatic activity had to adapt to the dietary modification. The results of studies on the effect of prebiotics on animal health are often contradictory, as fermentability of prebiotics may be affected by several factors, such as the type and dose of the prebiotic for example. The study of Biggs et al.  demonstrated that excessively high prebiotic dose may have a negative impact on the gastrointestinal system and may delay the growth of animals. This could be related to the inability of gut bacteria to ferment the high amount of prebiotic provided in the diet. The opposite hypothesis is that GOS, as a prebiotic with a low degree of polymerization (PD), at a dose of 1 and 2%, proved to be too weak in relation to the enzymes responsible for mineral metabolism. So, further research is needed to understand this mechanism. Our analyses confirmed no statistically significant differences in Mg content between treatment groups, both in the case of the meat and the gills. These results were in line with Ortiz et al. , who demonstrated that Mg content in the fillet of rainbow trout was not affected by prebiotic supplementation at inclusion level of 5 g kg−1. Factors that can reduce Mg absorption are fiber, phytates, P, Ca, or vitamin D.
Phosphorus (P) is a structural component of DNA, RNA, and phospholipids, involved in the photosynthesis and synthesis of organic compounds and responsible for the proper condition of teeth and bones. Fish can be a rich source of P; the concentration of which, depending on the species, can reach up to 200 mg per 100 g of meat. Phosphorus deficiency in the fish bodies can lead to excessive fat accumulation and poor skeletal mineralization and deformity . It has also been shown that some phosphorus-containing compounds, such as phosphatidylinositol, play a very important role in preventing skeletal deformities . Because the content of this mineral in the water is too low, and moreover, the efficiency of its absorption from feed is low, P should be supplemented with the feed . Our studies have shown that as is the case of Ca, P concentration increased in the following order: meat < gills < skeleton (Figs. 1 and 2), but there were no statistically significant differences in P content between fish fed 1 and 2% GOS compared control treatment (0% GOS) for all tissues. However, noteworthy is the moderate increase in P of 2.33% (in the meat) recorded between C and B2 groups. Similarly, Ortiz et al.  demonstrated that content of P in the fillet of rainbow trout was not affected by FOS supplementation at inclusion level of 5 g kg−1.
In vertebrates, calcium forms a complex with phosphorus as hydroxyapatite, which is responsible for the structure and the mechanical strength of bones , and therefore, the Ca/P ratio is the most important indicator of good bone health because it prevents the reduction of bone mineral density . The ratio of Ca to P in the whole body of several fish species ranges from 0.7 to 1.6 . As numerous studies show, the value of this ratio should be 1:1 in consumed products, because the excess of calcium over phosphorus causes the formation of calcium triphosphate, which is not absorbed as this form of calcium triphosphate is not biologically available [59, 60]. Our analyses confirmed that Ca/P ratio in the skeleton was affected by GOS supplementation and its value increased from 1.91 (C group) to 2.25 (B1) and 2.22 (B2). Our results were similar to those obtained by Nwanna and Swartz  for common carp fed phytase.
Zinc (Zn) plays an important role in the proper functioning of an organism, especially of the immune system; it is a component of many metalloenzymes, regulates metabolism of carbohydrates, proteins, nucleic acids, and participates in insulin synthesis and in bone mineralization [60, 61]. The reduced rate of Zn uptake may be due to the presence of high amounts of calcium phosphate in feeds containing vegetable proteins, fiber, oxalates, phytates, and Fe . Our results regarding Zn concentration in various tissues were in agreement with Bochenek et al. , Brucka-Jastrzębska et al. , Papagiannis et al. , and Jabeen et al. . Prebiotic effect analyses revealed significantly higher amounts of Zn in the meat of fish from B1 and B2 groups in comparison with C group. Prebiotics like FOS and GOS promote growth of Bifidobacterium spp. that affect the synthesis of vitamin B6, which is responsible for better Zn absorption . Since there is little data in the literature on this topic with regard to carp, further research is required. On the other hand, prebiotics affect the production of short-chain fatty acids, lowering the intestinal pH, which may contribute to better absorption of Zn. As confirmed by numerous studies, the gills play active and passive roles in exchanges between the body and its aquatic environment, and this tissue is the major storage site for Zn [3, 66, 67], which our research confirmed. However, our studies did not confirm a significantly positive effect of GOS supplementation on Zn concentration in the gills in B1 and B2 groups compared to C group, in contrast to the results obtained by Madreseh et al.  for rainbow trout lactulose-fed.
Iron (Fe) is a cofactor of many enzymes and a component of blood and muscle chromoproteins. This metal supports the proper functioning of the nervous and immune systems. In addition, Fe is responsible for the detoxification of harmful substances in the liver and prevents anemia, as it is responsible for the production of red blood cells. Fe content of the muscles of fish is an important criterion for their suitability for consumption. Factors that inhibit Fe absorption from intestine are fiber, phytates, polyphenols, and tannins . Fe deficiency causes anemia, but its excess leads to the formation of reactive oxygen species, resulting in cell and tissue damage. Therefore, Fe homeostasis must be strictly controlled to maintain balance . Carp analyses showed that the tendency of Fe accumulation in various tissues was similar to those determined by Brucka-Jastrzębska et al. , Brucka-Jastrzębska and Protasowicki , and Tekin Özan and Aktan . As our analyses indicated, GOS addition caused significantly higher level of Fe in the meat of fish fed 2% GOS in comparison with C and B1 groups. These results were in contradiction with Ortiz et al. . Research confirms the beneficial effect of prebiotics on Fe absorption because fermentation of these substances by the natural intestinal microflora may lower pH and promote the reduction of Fe(III) to Fe(II), whose solubility is better. Moreover, prebiotics can stimulate the proliferation of epithelial cells to increase the absorption surface and stimulate the expression of proteins responsible for the transport of minerals in epithelial cells . In our previous study with the same fish , a significantly accelerated development of the intestine, an increase in the height and width of the villi and an increase in their surface due to the GOS were found. As confirmed by research, propionate which is produced by intestinal fermentation of oligosaccharides may stimulate promoting 6-aminolevulinate synthesis (γ-keto carboxylic acid and precursor to the synthesis of porphyrins). Also, oligosaccharides may lead to a change in iron-binding proteins, e.g., mucin and enhance Fe absorption in the small intestine . Carp analyses indicated that the tissues which contained the largest amounts of Fe were the gills. Fe is taken up by the gills in the form of free ions and chelates of this element . The hypothesis is that in a highly alkaline and oxidizing environment, Fe uptake through the gill epithelium is limited. Our research supports this hypothesis as we have observed a significantly higher concentration of Fe in the gills of fish fed 1 and 2% GOS, which may be due to the prebiotic lowering environmental pH, but this mechanism requires further research.
Antagonist relationships occur when minerals have a similar electronic configuration and ion radius and compete for binding sites. Synergistic relationships occur when one element strengthens the role of another. In turn, the complex interrelationships between Fe, Zn, and Cu are more complex . Understanding the mechanism of the correlation of one element with another can be used as an indicator of their co-location in biological tissues . Studies of Wepener et al.  have shown that Cu (and possibly Fe) will have a greater tendency to accumulate in the gills than, for example, Zn or Ca. Our analyses confirmed positive correlation between Fe and Ca in the gills in B2 group which indicated that Ca had affinity for divalent metal transporter (DMT1) [71, 73]. In can be concluded that Fe and Ca may share uptake pathway via the DMT-1. However, it should be taken into account that the interaction between Fe and Ca depends on the form of calcium. Carbonates and phosphates, unlike calcium citrate, inhibit Fe absorption. Despite the fact that GOS supplementation did not affect the level of Ca accumulation in carp tissues, our analysis showed that 2% GOS addition caused a statistically significant increase in Fe in the gills. This could have had a significant impact on the positive correlation between these minerals in B2 group.
Positive correlations between Fe and Zn and between Mg and P in the skeleton in B2 group were calculated, despite the fact that these elements are considered antagonists to each other. Despite the fact that our studies confirmed the greatest accumulation capacity of Zn in the gills and Zn content in the skeleton was lower, this metal confirmed a synergistic interaction with Fe in the group of fish treated with 2% GOS supplementation. The interaction between Fe and Zn depends on the ratio of these metals to each other. The lack of published data on this topic requires further research on Zn metabolism, especially based on the analysis of vitamins and other minerals affecting Zn absorption.
Analyses confirmed positive correlation between Mg and P in the meat in B2 group. Although P and Mg are mainly involved in the bone mineralization process, their presence in the muscles is essential for the proper functioning of the organism. Both of these macroelements are responsible for conducting nerve impulses. Therefore, taking into account their proven antagonistic effect, the use of 2% GOS supplementation should be considered positive with regard to the correlation between these two elements. Due to the fact that there is no available published data about the effects of GOS on the relationship between minerals in carp tissues, this requires further analyses.
The results from the current study showed that dietary GOS supplementation had a positive effect on absorption of some minerals in common carp tissues. The feed with 1 and 2% of GOS supplementation significantly enhanced the concentration of Zn in the meat and skeleton. Fe concentration was significantly higher in the B2 group compared to B1 and C in the meat and gills. One percent and 2% GOS supplementation significantly enhanced Fe content in the skeleton. Mg concentration was significantly higher in the skeleton of fish from B1 group compared to C group. A significant effect of 1 and 2% GOS supplementation on Ca/P ratio in the skeleton was also confirmed. Supplementation of feed with 2% GOS significantly influenced the positive correlations between Mg and P in the meat and skeleton, Fe–Ca correlation in gills, and Fe–Zn correlation in the skeleton. Based on the analysis of the mineral profile in different tissues, we can conclude that the prebiotic could be a potential dietary additive for farmed common carp, due to the significant increase in Fe and Zn, for example. The increased absorption of certain minerals may be caused due to the production of short-chain fatty acids, lowering the intestinal pH and regulating the factors responsible for the transport of divalent metals. Absorption of metals may be enhanced by vitamin synthesized by intestinal bacteria, which population is supported prebiotic. Another factor enhancing the minerals absorption may be an increase of the intestine development, an increase in the height and width of the villi, and an increase in their surface as a result of GOS supplementation, which was confirmed by our previous research on the same fish. Nevertheless, further research is needed in this topic to determine the detailed effects of GOS supplementation on minerals retention and on the interactions between minerals in different fish tissues.
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
Prabhu PAJ, Schrama JW, Kaushik SJ (2016) Mineral requirements of fish: a systematic review. Rev Aquac 8(2):172–219. https://doi.org/10.1111/raq.12090
Krupa-Kozak U, Świątecka D, Bączek N, Brzóska MM (2016) Inulin and fructooligosaccharide affect: in vitro calcium uptake and absorption from calcium-enriched gluten-free bread. Food Funct 7:1950–1958. https://doi.org/10.1039/c6fo00140h
Lall SP (2002) The minerals. In: Halver J.E. and Hardy R.W, Fish Nutrition 259–308
Lochmann R, Phillips H, Xie L (2011) Effects of a dairy–yeast prebiotic and water hardness on the growth performance, mineral composition and gut microflora of fathead minnow (Pimephales promelas) in recirculating systems. Aquac 320(1–2):76–81. https://doi.org/10.1016/j.aquaculture.2011.08.004
Kamler E, Kamiński R, Wolnicki J, Sikorska J, Wałowski J (2012) Effects of diet and temperature on condition, proximate composition and three major macro elements, Ca, P and Mg, in barbel Barbus barbus juveniles. Rev Fish Biol Fish 18(4):767–777. https://doi.org/10.1007/s11160-012-9256-8
Sikorska J (2010) Dietary causes of body deformities in larval and juvenile fish in aquaculture. Part 1. Mineral substances. Komunikaty Rybackie 4(117):1–4
Lall SP, Lewis-McCrea LM (2007) Role of nutrients in skeletal metabolism and pathology in fish — an overview. Aquac. 267:3–19
Hussein MS, Zaghlol A, Abd El Hakim NF, El Nawsany M, Abo-State HA (2016) Effect of different growth promoters on growth performance, feed utilization and body composition of common carp (Cyprinus carpio). J Fish Aquat Sci 11:370–377
Eurostat (2018) Agriculture, forestry and fishery statistics. Statistical books. https://ec.europa.eu/eurostat/documents/3217494/9455154/KS-FK-18-001-ENN.pdf/a9ddd7db-c40c-48c9-8ed5-a8a90f4faa3f
FAO, Fisheries and Aquaculture, National Aquaculture Sector Overview – Poland 2020. http://www.fao.org/fishery/countrysector/naso_poland/en
Roberts RJ (2002) Nutritional pathology. In: Halver J.E. and Hardy R.W. (eds), Fish Nutrition, Third Edition. Elsevier Science 453–504
Nwanna LC, Schwarz FJ (2007) Effect of supplemental phytase on growth, phosphorus digestibility and bone mineralization of common carp (Cyprinus carpio L). Aquac Res 38(10):1037–1044. https://doi.org/10.1111/j.1365-2109.2007.01752.x
Kamiński R, Korwin-Kossakowski M, Kusznierz J, Myszkowski L, Stanny A, Wolnicki J (2005) Response of a juvenile cyprinid, lake minnow Eupallasella perenurus (Pallas), to different diets. Aquac Int 13:479–486. https://doi.org/10.1007/s10499-005-7899-3
Myszkowski L, Kamiński R, Quiros ML, Stanny A, Wolnicki J (2012) Dry diet-influenced growth, size variability, condition and body deformities in juvenile crucian carp Carassius carassius L. reared under controlled conditions. Arch Pol Fish 20:157–163. https://doi.org/10.2478/v10086-012-0019-x
Wolnicki J, Myszkowski L, Korwin-Kossakowski M, Kamiński R, Stanny A (2006) Effects of different diets on juvenile tench, Tinca tinca (L.) reared under controlled conditions. Aquac Int 14:89–98. https://doi.org/10.1007/s10499-005-9017-y
Akrami R, Razeghi Mansour M, Ghobadi S, Ahmadifar E, Shaker Khoshroudi M, Moghimi Haji MS (2013) Effect of prebiotic mannan oligosaccharide on hematological and blood serum biochemical parameters of cultured juvenile great sturgeon (Huso huso Linnaeus, 1754). J Appl Ichthyol 29:1214–1218. https://doi.org/10.1111/jai.12245
Bharathi S, Cheryl A, Rajagopalasamy CBT, Uma A, Ahilan B, Aanand S (2019) Functional feed additives used in fish feeds. Int J Fish Aquat Stud 7(3):44–52
Cerezuela R, Meseguer J, Esteban A (2011) Current knowledge in symbiotic use for fish aquaculture: a review. J Aquac Res Dev S1:008. https://doi.org/10.4172/2155-9546.S1-008
Khangwal I, Shukla P (2019) Potential prebiotics and their transmission mechanisms: recent approaches. JFDA 27:649–656
Mousavi E, Mohammadiazarm H, Mousavi SM, Ghatrami ER (2016) Effects of inulin, savory and onion powders in diet of juveniles carp Cyprinus carpio (Linnaeus 1758) on gut microflora, immune response and blood biochemical parameters. TrJFAS 16:831–838
Ebrahimi G, Ouraji H, Khales MK, Sudagar M, Barari A, Zarei Dangesaraki M, Jani Khalili KH (2012) Effects of a prebiotics, Immunogen® on feed utilization, body composition, immunity and resistance of Aeromonas hydrophila infection in the common carp Cyprinus carpio (Linnaeus) fingerlings. J Anim Physiol Anim Nutr 96:591–599. https://doi.org/10.1111/j.1439-0396.2011.01182.x
Ganguly S, Dora KC, Sarkar S, Chowdhury S (2012) Supplementation of prebiotics in fish feed: a review. Rev Fish Biol Fisheries 23:195–199. https://doi.org/10.1007/s11160-012-9291-5
Madreseh S, Ghaisari HR, Hosseinzadeh S (2019) Effect of lyophilized, encapsulated Lactobacillus fermentum and lactulose feeding on growth performance, heavy metals, and trace element residues in rainbow trout (Oncorhynchus mykiss) tissues. Probiotics Antimicrob Proteins 11(4):1257–1263. https://doi.org/10.1007/s12602-018-9487-7
Yeung CK, Glahn RP, Welch RM, Miller DD (2005) Prebiotics and iron bioavailability – is there a connection? Int J Food Sci 70(5):88–92
Yousefian M, Amiri MS (2009) A review of the use of probiotic in aquaculture for fish and shrimp. Afr J Biotechnol 8:7313–7318 http://www.academicjournals.org/AJB
Burr G, Hume M, Neill VH, Gatlin DM (2008) Effects of prebiotics on nutrient digestibility of soybean-meal-based diets by red drum (Sciaenops ocellatus). Aquacul Res 39:1680–1686. https://doi.org/10.1111/j.1365-2109.2008.02044.x
Dawood MAO, Koshio S, Esteban MÁ (2018) Beneficial roles of feed additives as immunostimulants in aquaculture: a review. Rev Aquac 10(4):950–974. https://doi.org/10.1111/raq.12209
Whisner CM, Castillo LF (2018) Prebiotics, bone and mineral metabolism. Calcif Tissue Int 102:443–479. https://doi.org/10.1007/s00223-017-0339-3
McCabe L, Britton RA, Parameswaran N (2015) Prebiotic and probiotic regulation of bone health: role of the intestine and its microbiome. Curr Osteoporos Rep 13(6):363–371. https://doi.org/10.1007/s11914-015-0292-x
Gibson GR, Hutkins R, Sanders ME, Prescott SL, Reimer RA, Salminen SJ, Scott K, Stanton C, Swanson KS, Cani PD, Verbeke K, Reid G (2017) Expert consensus document: the International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics. Nat Rev Gastroenterol Hepatol 14:491–502. https://doi.org/10.1038/nrgastro.2017.75
Haq Z, Khan AA (2018) Prebiotics: the gut ecology modifiers. J Entomol Zool Stud 6(3):1816–1820
Macfarlane S, Macfarlane GT, Cummings J (2006) Review article: prebiotics in the gastrointestinal tract. Aliment Pharmacol Ther 24:701–714. https://doi.org/10.1111/j.1365-2036.2006.03042.x
Ortiz LT, Velasco RS, Rodriguez M, Trevino J, Tejedor JL, Alzueta C (2012) Effects of inulin and fructooligosaccharides on growth performance, body chemical composition and intestinal microbiota of farmed rainbow trout (Oncorhynchus mykiss). Aquacul Nut 19(4):475–482. https://doi.org/10.1111/j.1365-2095.2012.00981.x
Niemiec M, Cupiał M, Klimas A, Szeląg-Sikora A, Sikora J (2014) Accumulation of iron in selected elements of the pond ecosystem food chain. Proceedings of ECOpole 8(1):231–237. https://doi.org/10.2429/proc.2014.8(1)030
Tzortzis G, Goulas A, Gibson GR (2005) Synthesis of prebiotic galactooligosaccharides using whole cells of a novel strain, Bifidobacterium bifidum NCIMB 41171. Appl Microbiol Biotechnol 68(3):412–416. https://doi.org/10.1007/s00253-005-1919-0
Ziółkowska E, Bogucka J, Dankowiakowska A, Rawski M, Mazurkiewicz J, Stanek M (2020) Effects of a trans-galactooligosaccharide on biochemical blood parameters and intestine morphometric parameters of common carp (Cyprinus carpio L.). Animals 10(4):723. https://doi.org/10.3390/ani10040723
Leary S, Underwood W, Anthony R, Cartner S (2013) AVMA guidelines for the euthanasia of animals: 2013 edition; AVMA: Schaumburg, 67–73
Directive 2010/63/EU of the European Parliament and of the council of 22 September 2010 on the protection of animals used for scientific purposes
NRC (2011) Nutrient requirement of fish and shrimp. The National Academies Press, Washington, DC, Animal Nutrition Series
De Silva SS, Anderson TA (1995) Fish nutrition in aquaculture. Chapmann & Hall, London, 319 pp
Takeuchi T, Satoh S, Kiron V (2002) Common carp, Cyprinus carpio. In: Webster CD, Lim C (eds) Nutrient requirements and feeding of finfish for aquaculture. CABI Publishing, New York, pp 245–261
Horváth L, Tamás G, Seagrave C (2002) Carp and pond fish culture, 2nd edn. Blackwell Science, Oxford, UK
Miyatake H (1997). Carp, Yoshoku, 34(5):108-111(in Japanese)
Topic Popovic N, Strunjak-Perovic I, Coz-Rakovac R, Barisic J, Jadan M, Persin Berakovic A, Sauerborn Klobucar R (2012) Tricaine methane-sulfonate (MS-222) application in fish anaesthesia. J Appl Ichthyol 28:553–564
Hoffmann L, Rawski M, Nogales-Merida S, Mazurkiewicz J (2020) Dietary inclusion of Tenebrio molitor meal in sea trout larvae rearing: effects on fish growth performance, survival, condition, and GIT and liver enzymatic activity. Ann Anim Sci 20(2):579–598. https://doi.org/10.2478/aoas-2020-0002
Józefiak A, Nogales-Merida S, Rawski M, Kierończyk B, Mazurkiewicz J (2019) Effects of insect diets on the gastrointestinal tract health and growth performance of Siberian sturgeon (Acipenser baerii Brandt, 1869). BMC Vet Res 15:348. https://doi.org/10.1186/s12917-019-2070-y
Liang JJ, Liu YJ, Yang ZN, Tian LX, Yang HJ, Liang GY (2012) Dietary calcium requirement and effects on growth and tissue calcium content of juvenile grass carp (Ctenopharyngodon idella). Aquac Nutr 18:544–550. https://doi.org/10.1111/j.1365-2095.2011.00916.x
Brucka-Jastrzębska E, Kawczuga D, Rajkowska M, Protasowicki M (2009) Levels of microelements (Cu, Zn, Fe) and macroelements (Mg, Ca) in freshwater fish. J Elem 14(3):437–447
Łuczyńska J, Tońska E, Borejszo Z. (2011) Content of macro- and microelements, and fatty acids in muscles of salmon (Salmo salar L.), rainbow trout (Oncorhynchus mykiss Walb.), and carp (Cyprinus carpio L.). ŻYWNOŚĆ. Nauka. Technologia. Jakość 3(76):162–172
Cashman K (2003) Prebiotics and calcium bioavailability. Curr Issues Intest Microbiol 4:21–32
Bromage N, Randall C, Duston J, Thrush Mand Jones J (1993) Environmental control of reproduction in salmonids. In Recent Advances in Aquaculture IV pp 55–65
Perez-Conesa D, Lopez G, Abellan P, Ros G (2006) Bioavailability of calcium, magnesium and phosphorus in rats fed probiotic, prebiotic and synbiotic powder follow-up infant formulas and their effect on physiological and nutritional parameters. J Sci Food Agric 86:2327–2336
Brucka-Jastrzębska E, Protasowicki M (2006) Levels of selected metals in tissues and organs of 5-month-old carp (Cyprinus carpio L.). Acta Sci Pol Piscaria 5(2):3–16
Brucka-Jastrzębska E, Kawczuga D (2011) Levels of magnesium in tissues and organs of freshwater fish. J Elem 16(1):7–20
Guerreiro I, Serra CR, Pousão-Ferreira P, Oliva-Teles A, Enes P (2017) Prebiotcs effect on growth performance, hepatic intermediary metabolism, gut microbiota and digestive enzymes of white sea bream (Diplodus sargus). Aquacult Nutrit 24(1):153–163. https://doi.org/10.1111/anu.12543
Biggs P, Parsons CM, Fahey GC (2007) The effects of several oligosaccharides on growth performance, nutrient digestibility, and cecal microbial populations in young chicks. Poult Sci 86(11):2327–2336. https://doi.org/10.3382/ps.2007-00427
Sikorska J, Wolnicki J, Kamiński R, Stolovich V (2012) Effect of different diets on body mineral content, growth, and survival of barbel, Barbus barbus (L.), larvae under controlled conditions. Arch Pol Fish 20:3–10. https://doi.org/10.2478/v10086-012-0001-7
Cahu C, Zambonino Infante J, Takeuchi T (2001) Nutrients affecting quality in marine fish larval development. Eur Aquacult Soc Spec Publ 30:115–116
Ye C-X, Liu YJ, Tian L-X, Mai K-S, Du Z-Y, Yang H-J, Niu J (2006) Effect of dietary calcium and phosphorus on growth, feed efficiency, mineral content and body composition of juvenile grouper, Epinephelus coioides. Aquacult 255:263–271. https://doi.org/10.1016/j.aquaculture.2005.12.028
Chavez-Sanchez C, Martinez-Palacios CA, Martinez-Perez G, Ross LG (2000) Phosphorus and calcium requirements in the diet of the American cichlid Cichlasoma urophthalmus (Günther). Aquac Nutr 6:1–9. https://doi.org/10.1046/j.1365-2095.2000.00118.x
Kyu Song S, Beck BR, Kim D, Park J, Kim J, Kim HD, Ringø E (2014) Prebiotics as immunostimulants in aquaculture.: a review. Fish Shellfish Imm 40(1):40–48. https://doi.org/10.1016/j.fsi.2014.06.016
Bochenek I, Protasowicki M, Brucka-Jastrzębska E (2008) Concentration of Cd, Pb, Zn and Cu in roach Rutilus rutilus (L.) from the lower reaches of the Oder River, and their correlation with concentrations of heavy metals in bottom sediments collected in the same area. Arch Pol Fish 16(1):21–36
Papagiannis I, Kagalou I, Leonardos J, Petridis D, Kalfakakou V (2004) Copper and zinc in four freshwater fish species from Lake Pamvotis (Greece). Environ Int 30:357–362. https://doi.org/10.1016/j.envint.2003.08.002
Jabeen F, Chaudhry AS (2010) Monitoring trace metals in different tissues of Cyprinus carpio from the Indus River in Pakistan. Environ Monit Assess 170:645–656. https://doi.org/10.1007/s10661-009-1263-4
Dylus E, Buda B, Górska-Frączek S, Brzozowska E, Gamian A (2013) Surface proteins of bacteria of the genus Bifidobacterium. Advances in Hygiene and Experimental Medicine 67:402–412. https://doi.org/10.5604/17322693.1049285
Dural M, Lugal Göksu MZ, Akif Özak A, Derici B (2006) Bioaccumulation of some heavy metals in different tissues of Dicentrarchus labrax L, 1758, Sparus aurata L, 1785, and Mugil cephalus L, 1758 from the Çamlik Lagoon of the eastern cost of Mediterranean (Turkey). Environ Monit Assess 118:65–74
Brooks RR, Rumsey D (1974) Heavy metals in some New Zealand commercial sea fishes mar. Freshw Res 8(1):155–166
Zhao N, Enns CA (2012) Iron transport machinery of human cells: players and their interactions. Curr Top Membr 69:67–93. https://doi.org/10.1016/B978-0-12-394390-3.00003-3
Tekin Özan S, Aktan N (2012) Relationship of heavy metals in water, sediment and tissues with total length, weight and seasons of Cyprinus carpio L,1758 from Işikli Lake (Turkey). J Zool 44:1405–1416 https://www.researchgate.net/publication/286169833
Grizard D, Barthomeuf C (1999) Non-digestible oligosaccharides used as prebiotic agents: mode of production and beneficial effects on animal and human health. Reprod Nutr Dev 39:563–588
Saibua Y, Jamwal A, Feng R, Peak D, Niyogi S (2018) Distribution and speciation of zinc in the gills of rainbow trout (Oncorhynchus mykiss) during acute waterborne zinc exposure: interactions with cadmium or copper comparative biochemistry and physiology. Part C 206-207:23–31. https://doi.org/10.1016/j.cbpc.2018.02.004
Wepener V, van Vuren JHJ, Du Preez HH (2001) Uptake and distribution of a copper, iron and zinc mixture in gill, liver and plasma of a freshwater teleost, Tilapia sparrmanii. Water SA 27(1):99–108
Garrick MD, Singleton ST, Vargas F, Kuo HC, Zhao L, Knöpfel M, Davidson T, Costa M, Paradkar P, Roth JA, Garrick LM (2006) DMT1: which metals does it transport? Biol Res 39:79–85. https://doi.org/10.4067/S0716-97602006000100009
This work has been supported by the Polish National Agency for Academic Exchange under Grant No. PPI/APM/2019/1/00003. Research conducted by the statutory funding No. 506.511.04.00 of the Faculty of Veterinary Medicine and Animal Science Poznan University of Life Sciences, Poland; Division of Inland Fisheries and Aquaculture.
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Ziółkowska, E., Bogucka, J., Mazurkiewicz, J. et al. Effects of a Trans-Galactooligosaccharide on Minerals Content of Common Carp (Cyprinus carpio L.) Tissues. Biol Trace Elem Res (2021). https://doi.org/10.1007/s12011-021-02600-w