Distinct B cell profiles characterise healthy weight and obesity pre- and post-bariatric surgery.

BACKGROUND/OBJECTIVES: Obesity-associated metabolic dysfunction and inflammation can be ameliorated by bariatric surgery. While obesity is also linked to impaired B cell activation, differentiation, and persistence in response to infection and vaccination little is known about post-operative immune B cell compartment and to what extent dysregulation in B cell pathways can be reversed. To bridge this gap in knowledge, we carried out in-depth evaluation of B cell composition in individuals with obesity prior to and following bariatric surgery compared to lean controls. SUBJECTS/METHODS: We recruited individuals with obesity (BMI at least 35 kg/m2) before bariatric surgery (n = 21) and followed them up 6 months post-operatively (n = 17). As controls we recruited age- and sex-matched lean (BMI < 25) individuals (n = 18). We carried out comprehensive immunophenotyping of peripheral blood B cells as well as interrogated their association with inflammatory and metabolic parameters. RESULTS: In obesity the balance of antigen-inexperienced and memory B cells in the peripheral blood is altered, with an expansion of naïve and a reduction in total memory B cells. 6 months following bariatric surgery this balance is restored. However, post-operative patients are uniquely characterised by an increase in B cell subsets associated with chronic inflammation - CD11c+CXCR5-IgD-CD27- double negative 2 (DN2) B cells and CD27+CD38++ plasmablasts. Correlations between B cells subsets, inflammatory and metabolic parameters were distinct in lean people and individuals with obesity pre- and post-bariatric surgery. CONCLUSIONS: Bariatric surgery patients display a unique B cell profile 6 months post-operatively; this bears minimal resemblance to that of pre-operative patients and only partially overlaps with that of lean controls. Post-operative differences in the B cell compartment compared to lean controls are detected despite global amelioration of inflammation and restoration of metabolic health. Collectively, this indicates that bariatric surgery creates a specific immunometabolic state with potential implications for health outcomes.

The first comprehensive population size estimations for the highly endangered largest diving beetle Dytiscus latissimus in Europe.

Dytiscus latissimus (Coleoptera Dytiscidae) is an endangered diving beetle throughout its range. It is one of the two species of Dytiscidae listed in Annex II of the Habitats Directive, IUCN red list and in many national level legislations and therefore strictly protected. The conservation of endangered species first of all requires an assessment of their population size. Until now, a method has not been developed for estimating the size of D. latissimus populations. The article summarizes the results of two studies carried out independently in Germany and Latvia. Both studies were carried out in one water body used recapture method but with a different spatial placement of traps, which, according to our data, is an important factor in population estimation. We evaluated Jolly-Seber and Schnabel approaches of estimating aquatic beetle's populations and found that confidence intervals obtained by different methods in our research do not differ significantly, but combination of both models provide the most accurate estimates of population dynamics. As part of the study, we concluded that the populations of Dytiscus latissimus are relatively closed, so we accept that the Schnabel estimate shows more accurate data. By fixing the places of capture of each individual, it was found that females live mainly locally, and males actively move within the water body. This aspect indicates the advantage of the spatial placement of traps compared to the use of transects. The results of our study show a significantly higher number of both captured and recaptured males Such a sex ratio may indicate both a greater activity of males and differences in the sex ratio in the population. The study confirmed that environmental changes, such as the water level in a water body, can also significantly affect the result of a population assessment. In the frame of D. latissimus monitoring, to obtain an objective estimation of the species population size we recommend using four traps for each 100 m of water body shoreline with 4-8 censuses, dependently on the recapture rate.

The amount of ghrelin-immunoreactive cells in the abomasum and intestines of 13-14-week-old calves supplemented with Jerusalem artichoke flour alone or in combination with Saccharomyces cerevisiae yeast.

Background and Aim: The use of antibiotics in animals for disease prevention and productivity has been banned in the European Union since 2006. Possible alternatives can be used prebiotics, probiotics, and synbiotics. These compounds can improve feed digestion and absorption in the gastrointestinal tract with identical nutrient uptake, while imparting the feeling of satiety, which reduces the activity of ghrelin-immunoreactive (IR) cells. The number of studies performed on the activity of ghrelin-IR cells in ruminants is insufficient. In particular, there are few such studies in calves during the transition period from being a relatively monogastric animal to a ruminant. The present study aimed to evaluate the effect of Jerusalem artichoke flour (containing ~50% prebiotic inulin) and a new, commercially unavailable synbiotic (combination of Jerusalem artichoke flour and Saccharomyces cerevisiae strain 1026) on the amount of ghrelin-IR cells in the abomasum and intestines of 13-14-week-old calves. Materials and Methods: Fifteen crossbreed, Holstein Friesian and Red Holstein calves (Bos taurus) (32±4 days, 72.1±11.34 kg) were used. Calves were allocated into three groups: Control group (CoG, n=5) received the standard diet, prebiotic group (PreG, n=5) received 12 g of flour of Jerusalem artichoke (Helianthus tuberosus) per head containing 6 g of prebiotic inulin in addition to the standard diet, and synbiotic group (SynG, n=5) received a synbiotic in addition to the standard diet which consisted of two different products: 12 g of flour of Jerusalem artichoke per head containing 6 g of prebiotic inulin and probiotic 5 g of a yeast S. cerevisiae strain 1026. Feed additives were added to the concentrate once a day for 56 days. On days 1, 28, and 56, the live weight of the calves was determined. On day 56 of the experiment, three calves from each group were slaughtered. Histological samples were collected from the two parts of each calf abomasum: Pars pylorica and pars fundalis and the middle part of the duodenum and jejunum. Immunohistochemical tissue staining methods were used to detect ghrelin-IR cells. Results: The live weight of the slaughtered calves on day 56 was 115.3±21.73 kg in CoG, 130.0±17.32 kg in PreG, and 119.0±7.94 kg in SynG. Ghrelin-IR cells were more abundantly localized in the cytoplasm of the abomasum muscle gland cells in pars fundalis and pars pylorica, and to a lesser extent in the duodenum and jejunum. The number of ghrelin-IR cells in the abomasal fundic gland area was significantly higher in the CoG, than in the PreG and SynG (p=0.0001), while the difference between the PreG and SynG was not significant (p=0.700). Conclusion: The addition of Jerusalem artichoke flour and its combination with the yeast S.cerevisiae stain 1026 in calves resulted in a lower number of ghrelin-IR cells in the abomasum, duodenum, and jejunum and, although insignificantly, increased live weight (p=0.491), suggesting that calves in these groups with the same feed intake as the CoG had a better breakdown of nutrients, thus having a longer feeling of satiety.

The Impact of Inulin and a Novel Synbiotic (Yeast Saccharomyces cerevisiae Strain 1026 and Inulin) on the Development and Functional State of the Gastrointestinal Canal of Calves.

Successful management of the dairy industry is closely related to rearing healthy calves. The proper development of the gastrointestinal canal is crucial to reach this goal. One of the strategies to promote this development is the addition of feed additives to the diet. This research aimed to determine the impact of prebiotic inulin and a new, not commercially available synbiotic (mix of prebiotic inulin and probiotic S. cerevisiae strain 1026) on the development of the gastrointestinal canal of calves by comparing the weight of the stomach, its relative ratio to body weight and evaluating pH, and histological changes in different parts of the gastrointestinal canal and assess whether or not the addition of inulin to the yeast S. cerevisiae improves the abovementioned parameters. We used prebiotic inulin (6 g) and a synbiotic (prebiotic inulin 6 g and probiotic Saccharomyces cerevisiae strain 1026, 5 g). The 56-day long research was conducted with fifteen crossbreed calves (32 ± 6 days old) organized in the control group (CoG), the prebiotic group (PreG), and the synbiotic group (SynG). We determined pH, morphological parameters of different parts of the digestive canal, and morphometric parameters of the stomach. The addition of prebiotic inulin to calves' diet causes the increase of pH in rumen, abomasum, and intestines but when inulin was added to S. cerevisiae, pH decreased and was even lower than in the control group. Prebiotic inulin and its synbiotic with yeast S. cerevisiae positively impact the development of almost all morphological structures of rumen saccus dorsalis, rumen saccus ventralis, and intestine; moreover, calves from the synbiotic group showed better results in virtually all parameters. However, both inulin and synbiotic did not affect the weight and relative weight of different parts of the stomach. Tested synbiotic has the potential to promote the development of the rumen and other parts of the digestive canal of calves.

Impact of inulin and yeast containing synbiotic on calves' productivity and greenhouse gas production.

AIM: The research aimed to determine the impact of synbiotic: 6 g of prebiotic inulin and 5 g of probiotic Saccharomyces cerevisiae strain 1026 on calves' productivity and greenhouse gas (GHG) production. MATERIALS AND METHODS: The research was conducted with 10 Holstein Friesian and Red Holstein (Bos taurus L.) crossbreed calves of mean age 33±6 days and initial body weight 73.4±12.75 kg. We added the synbiotic into the diet of five dairy crossbreed calves (SynG) and five calves in control group (CoG) received non-supplemented diet. The duration of the experiment was 56 days. The weight of calves and amount of methane (CH4) and carbon dioxide (CO2) in the rumen were determined on day 1, 28, and 56. On day 56, three calves from each group were slaughtered. Meat samples were assessed for some indicators of meat quality. The main methanogens were detected in the rumen fluid and feces. RESULTS: The weight gain during the whole experiment period of 56 days was higher in the SynG (62.6±13.75 kg) compared to CoG (36.8±7.98 kg) calves (p<0.01). There were no significant differences in the levels of protein (%), fat (unsaturated and saturated - %), and cholesterol (mg/100 g) in meat samples from both groups. At the end of the experiment, the amount of CH4 in calves' rumen in CoG was higher (Me=792.06 mg/m3, interquartile range [IQR] 755.06-873.59) compared to SynG (Me=675.41 mg/m3, IQR 653.46-700.50) group (p<0.01). The values for CO2 were also increased in CoG (Me=4251.28 mg/m3, IQR 4045.58-4426.25) compared to SynG (Me=3266.06 mg/m3, IQR 1358.98-4584.91) group (p=0.001). There were no significant differences in the calves' weight and certain methanogen species in rumen liquid and feces on the 56th day of the experiment. Significantly higher results in the parameter total prokaryotes (V3) (bacteria+archaea) in rumen fluid were in SynG, whereas significantly higher results in the parameter total methanogens Met630/803 in rumen fluid were in CoG, p<0.05. CONCLUSION: The main results showed that the synbiotic can increase the daily weight gain in calves and decrease the amount of GHG in rumen but does not impact different methanogen species in rumen liquid and feces and meat protein, fat, and cholesterol levels.

The distribution of digenean metacercariae within bream (Abramis brama) gill apparatus: preferences, co-occurrence and interactions of parasites.

Species-specific microenvironmental preferences and interactions between parasite species have been the focus of many ecological studies. Here, we studied the distribution of ectoparasite species within the gill apparatus of bream (Abramis brama) from Lake Lubans (Latvia) to establish whether digenean metacercariae: (1) prefer specific patches within the gill apparatus; (2) co-occur in the same patches with monogeneans and copepods within a host individual; and (3) interact with monogeneans and copepods. We recorded all parasites on gill arches of the same host species and used null models to analyse co-occurrences of digenean metacercariae, monogeneans and copepods. Zero-inflated mixture models were used to define the preferred patches of parasites. We found that digenean metacercariae (Bucephalus polymorphus) prefer specific patches of the gill apparatus to encyst, and shared these preferences with monogeneans and copepods, but did not interact with them. We concluded that digenean metacercariae have a species-specific microenvironmental preference to encyst in the gill apparatus and their occurrence (even in high numbers) does not reduce the success of attachment of monogeneans and copepods in the same gill patches.