Aneta Kopeć

Objective: This study was designed to evaluate the effect of baked freeze-dried sprats (SPR) added to experimental diets of Wistar rats, with induced streptozotocin (STZ) oxidative stress, on selected biochemical markers involved in antioxidative, immune responses, and thyroid function. Material and Methods: Male Wistar rats (n = 48) were assigned to four experimental groups: C control group, STZ group of rats injected with streptozotocin, SPR group fed diet containing sprats, and STZ + SPR group. Concentrations of selected minerals were determined in urine, feces and selected organs. Serum thyroid hormones (T3, T4), a thyroid-stimulating hormone (TSH) concentration, and the activity of antioxidant enzymes (GPx, GR, SOD) were assessed. The relative expression of Txnrd1, Gpx1/3, Dio1–3 was quantified. Results: The highest concentrations of Mg, I, and Se were observed in the liver of the SPR and STZ + SPR groups compared with the C and STZ groups. T₄ was significantly higher in all experimental groups compared to the C group. mRNA Txnrd1 expression was higher in the thyroid of the SPR and STZ + SPR groups than in the C and STZ groups. The thyroid in STZ + SPR exhibited higher Dio1 with lower Dio2 and Dio3 expression. Conclusions: It can be concluded that baked sprats are the source of bioavailable minerals involved in the reduction of oxidative stress and the modulation of iodine metabolism in rats with oxidative stress caused by impaired glucose metabolism.

The effects of household cooking on mercury speciation in whole small pelagic fish remain insufficiently understood. To address this gap, total mercury (T-Hg), methylmercury (MeHg), and Hg(II) were determined in wet whole-fish homogenates, including viscera, of sardines and sprats before and after boiling, steaming, baking, and frying. T-Hg was determined by AMA-254 and mercury species by HPLC-ICP-MS; results were expressed on wet-weight (ww), dry-weight (dw), and 100 g reference-portion bases. Frying yielded the highest dry matter, underscoring moisture-related differences among reporting bases. T-Hg concentrations ranged from 0.0518 to 0.1322 µg/g dw and MeHg from 0.0273 to 0.0624 µg/g dw. MeHg was detected in all samples, whereas Hg(II) exceeded the method detection limit only in baked and steamed sardines. MeHg amounts per 100 g ranged from 1.38 to 2.35 µg in sardines and from 0.95 to 1.79 µg in sprats. Within the tested batch, no treatment consistently reduced T-Hg or MeHg across both species. By combining analysis of the complete fish matrix with direct mercury speciation and multiple reporting bases, this study provides a food-relevant framework for interpreting mercury in processed small pelagic fish.

Small pelagic fish are nutrient-dense foods, but whether domestic cooking alters their capacity to modulate probiotic adhesion is unclear. We prepared sardines and sprats using five household techniques (raw, cooked, steamed, baked, and fried) and generated in vitro digestates using the INFOGEST method. We tested two concentrations in two intestinal co-cultures—Caco-2/HT29 and mucin-producing Caco-2/HT29-MTX. Adhesion of Lacticaseibacillus rhamnosus, Lactobacillus gasseri, and Lactobacillus brevis were quantified. Digestates altered adhesion in a probiotic strain species in a process-dependent manner. Sprat digestates from fried or baked preparations produced the strongest stimulation, exceeding 150% in Caco-2/HT29; responses in HT29-MTX were directionally similar but attenuated. In contrast, cooked or steamed sardine digestates frequently inhibited adhesion, particularly at 0.5% (e.g., L. gasseri < 50%). Raw preparations yielded divergent outcomes across models. A two-way ANOVA confirmed significant effects of processing, concentration, and their interaction, with the interaction explaining up to 21% of the observed variance. Across conditions, L. rhamnosus adhered most consistently, whereas L. brevis and L. gasseri were more environmentally sensitive. These findings suggest that standard cooking practices alter the bioactivity of fish-derived digestates and, consequently, the adhesion of beneficial lactobacilli in intestinal cell models, selecting sprats and employing dry-heat methods may favor probiotic–host interactions under in vitro conditions.

In recent decades, there has been increased in interest in the issue of heavy metal pollution in aquatic environments, which is directly linked to industrial development, the intensification of agriculture and ongoing urbanisation. Heavy metals such as mercury (Hg), lead (Pb), cadmium (Cd) and arsenic (As) belong to a group of particularly hazardous pollutants due to their persistence, lack of biodegradability and ability to accumulate in living organisms. Introduced into the aquatic environment from both natural and anthropogenic sources (e.g. industrial effluents, agricultural runoff), they can subsequently be taken up by aquatic organisms and incorporated into food chains. Study conducted in various regions of the world indicates, fish are an effective bioindicator of aquatic environmental pollution, and their analysis allows for the assessment of potential health risks to consumers. The objective of this study was evaluation of the effect of sprats or sardines addition to the experimental diets on accumulation of some heavy metals in selected organs of experimental rats.

Enzymatic antioxidant mechanisms constitute one of the elements protecting cells against the activity of free radicals. Proteins such as superoxide dismutase (SOD1), glutathione reductase (GSR), and heme oxygenase-1 (HMOX1) participate in maintaining redox balance and the cellular response to oxidative stress. Given their high mineral content—minerals being constituents of antioxidant enzymes—these fish may influence enzyme synthesis and the organism's antioxidant potential. The aim of the project was to evaluate the effect of roasted and freeze-dried sardines, included in experimental diets, on the expression levels of selected proteins associated with antioxidant defense in the livers of laboratory rats. Protein expression levels of SOD1, GSR, and HMOX1 were determined using the Western blot method.

According to current dietary guidelines, fish – particularly sea fish – should be eaten twice a week. Sardines are rich in minerals, omega-3 fatty acids and high-quality protein. Once absorbed, these nutrients can be used by the organism, amongst other things, to reduce oxidative stress and, consequently, to reduce inflammation. Minerals such as iodine, selenium, zinc and copper are often deficient in the common diet, which can have a significant impact on the body’s oxidative potential and the function of the immune system. The aim of the project was to assess the effect of baked and freeze-dried sardines added to experimental diets on selected biochemical parameters related to oxidative stress and the reduction of inflammation in experimental rats.

Fish are an important part of well-balanced diet. According to current dietary recommendations, they should be consumed twice a week. Sardines, being small-boned fish, are most often consumed whole, but in the form of canned or smoked products. These fish can be consumed after heat treatment, such as baking. In form of baked products, they are a source of high-quality protein, fatty acids, including n-3 fatty acids, and minerals (e.g., calcium, magnesium, iron, copper, and iodine). The aim of this project was to evaluate the effect of baked and freeze-dried sardines added to experimental diets on selected biochemical parameters related to lipid metabolism, oxidative stress, inflammation, and the bioavailability of selected minerals in rats with induced oxidative stress.

The immune system protects the human body against all types of infections and is designed to mitigate factors that influence its development. For this reason, people seeking to protect themselves against infections use various vitamin and mineral supplements and natural food products, especially herbs. Nutritional status plays an important role in the proper functioning of the immune system. It has been documented that protein, n-3 fatty acids, vitamins D and A, magnesium, calcium, iron, zinc, iodine and selenium are essential for the body's immune response. A well-balanced diet containing foods rich in the nutrients mentioned above may be one of the most important factors in preventing and combating SARS-CoV-2 and other infections. Sprats appear to be natural foods that can improve our nutritional status. They are a rich source of n-3 fatty acids, vitamin D, calcium, magnesium, zinc, selenium, and iodine. The aim of the project was to evaluate the effect of addtion of baked sprats in experimental diets and their influence on selected biochemical parameters related to oxidative stress and inflammation rat organism.