Immuno- and glyco-histochemistry as a tool to evaluate the oregano supplemented feed effects in pig gut

Morphological digital assessment and transcripts of gastric and duodenal visfatin in growing piglets fed with increasing amounts of polyphenols from olive mill waste extract

Visfatin is an adipokine with mediatory effects on inflammation. It is expressed at low levels in the pig stomach, but its role in the gastrointestinal (GI) tract is not well understood. This study explored visfatin expression and localisation in the stomach and duodenum of piglets fed varying levels of polyphenols derived from olive mill waste extract, known for their antioxidant and immunomodulatory properties. Twenty-seven piglets were assigned to three dietary groups: control (commercial feed), low polyphenol (120 ppm), and high polyphenol (240 ppm) groups. After 14 days of feeding, samples from the glandular stomach and duodenum were collected from 13 piglets. Immunohistochemistry (IHC), digital image analysis (DIA) using QuPath software, and double-labelled immunofluorescence were performed to detect visfatin-positive cells and co-localise them with serotonin. Additionally, relative gene expression of visfatin was assessed via RT-qPCR. Visfatin-positive cells were identified in 5 out of 13 piglets, localised mainly in the basal portion of gastric and intestinal glands. The morphology of those cells was consistent with neuroendocrine cells and confirmed by co-localisation of visfatin and serotonin. No significant differences were found in cell positivity or morphology between dietary groups or between tissues. However, visfatin transcript levels increased with the dose of polyphenolic extract. These findings suggest that dietary polyphenols may modulate visfatin gene expression in the GI tract. The study also highlights the value of digital anatomy for enhancing the accuracy and reproducibility of anatomical research. Further studies are needed to elucidate the functional role of visfatin transcript and protein in the porcine GI tract.

Effect of diets supplemented with coated plant essential oil on the growth performance, immunity, antioxidant activity, and fecal microbiota of weaned piglets

Introduction

This trial was conducted to compare the effect of diets supplemented with plant essential oil (PEO) and coated plant essential oil (CEO) on growth performance, immunity, antioxidant activity, and fecal microbiota of weaned piglets.

Methods

A total of 360 21-day-old weaned piglets were randomly allocated into three groups, namely, CON, PEO, and CEO (basal diets supplemented with 0, 500 mg/kg PEO, and 500 mg/kg CEO, respectively) for a 4-week feeding trial.

Results and discussion

The results showed that dietary supplementation with CEO improved the average final weight and average daily gain, decreased the diarrhea rate, increased antioxidant enzyme activities, enhanced immunoglobulin concentrations, and decreased concentrations of pro-inflammatory cytokines in the serum of weaned piglets (p < 0.05). In addition, CEO addition increased the fecal concentrations of propionic acid and isovaleric acid of piglets (p < 0.05). Spearman correlation analysis showed that fecal microorganisms at the genus level were closely correlated with the volatile fatty acid concentrations. The present study indicated that PEO and CEO could improve growth performance, enhance immunity, and increase antioxidant capacity by modulating the microbial flora in weaned piglets. Moreover, CEO addition seemed to offer more positive results than of PEO addition.

Pharmacological Applications and Action Mechanisms of Phytochemicals as Alternatives to Antibiotics in Pig Production

Antibiotics are widely used for infectious diseases and feed additives for animal health and growth. Antibiotic resistant caused by overuse of antibiotics poses a global health threat. It is urgent to choose safe and environment-friendly alternatives to antibiotics to promote the ecological sustainable development of the pig industry. Phytochemicals are characterized by little residue, no resistance, and minimal side effects and have been reported to improve animal health and growth performance in pigs, which may become a promising additive in pig production. This paper summarizes the biological functions of recent studies of phytochemicals on growth performance, metabolism, antioxidative capacity, gut microbiota, intestinal mucosa barrier, antiviral, antimicrobial, immunomodulatory, detoxification of mycotoxins, as well as their action mechanisms in pig production. The review may provide the theoretical basis for the application of phytochemicals functioning as alternative antibiotic additives in the pig industry.

Productive Performance and Meat Characteristics of Kids Fed a Red Orange and Lemon Extract

Simple Summary

Small ruminant farming can potentially adopt low-input strategies by using agro-industrial byproducts as alternative feeding sources. Byproducts are natural, and thus are preferred by consumers because most of them have antioxidant activity that may improve different aspects linked to meat quality and human health. For this reason, a red orange and lemon extract, (RLE) rich in anthocyanins, is tested as an oral additive on kids’ meat. No differences were recorded on animal performance, but on meat, RLE inclusion improves juiciness and reduces color deterioration. Moreover, RLE reduced cooking loss, and meat quality is positively influenced, due to both delaying lipid oxidation and a better fatty acid profile resulting in healthier meat for human consumption.

Abstract

This study evaluates the animal performance and meat characteristics of 60 Saanen suckling kids daily fed a red orange and lemon extract (RLE), rich in anthocyanins. In our methodology, after colostrum administration, animals are randomly assigned to two treatments: Treatment group (Group RLE; n = 30) that received RLE (90 mg/kg live body weight) as oral food additive, and a control group (Group CON; n = 30) that received a standard diet. Animals are slaughtered after 40 days. The RLE administration did not influence daily weight gain, carcass measurements, or incidences (expressed as a percentage) of different anatomical regions on the whole carcass weight. On the contrary, RLE supplementation significantly improved the oxidative profile of the meat seven days after slaughtering, as demonstrated by the reduced levels of thiobarbituric acid reactive substances (TBARS; p < 0.01) and hydroperoxides (p < 0.01) in Group RLE compared to Group CON. A significant influence of RLE administration is observed on day 7 for yellowness (p < 0.01). There are also lower saturated and higher monounsaturated and polyunsaturated fatty acids concentration in Group RLE meat (p < 0.01), which also shows lower atherogenic and thrombogenic indexes (p < 0.01) compared to Group CON. The study demonstrates that the supplementation of a diet with RLE rich in anthocyanins is effective to improve the meat quality.

Twenty years of histochemistry in the third millennium, browsing the scientific literature

Over the last twenty years, about 240,000 articles where histochemical techniques were used have been published in indexed journals, and their yearly number has progressively increased. The histochemical approach was selected by researchers with very different scientific interests, as the journals in which these articles were published fall within 140 subject categories. The relative proportion of articles in some of these journal categories did change over the years, and browsing the table of contents of the European Journal of Histochemistry, as an example of a strictly histochemical journal, it appeared that in recent years histochemical techniques were preferentially used to mechanistically investigate natural or experimentally induced dynamic processes, with reduced attention to purely descriptive works. It may be foreseen that, in the future, histochemistry will be increasingly focused on studying the molecular pathways responsible for cell differentiation, the maintenance or loss of the differentiated state, and tissue regeneration.

Influence of Different Feed Physical Forms on Mandibular Gland in Growing Pigs

Simple Summary

The study was carried out on growing pigs fed with different dietary treatments based on different grinding intensities and compactions of the same diet. Chewing acts are associated with salivary production and different extents of saliva fluidity also depend on the specific glycoconjugate content. Therefore, in order to have information about the modifications induced by different feed physical forms in the pig mandibular gland, the glycohistochemical profile and the presence of aquaporin 5, a channel protein modulating the saliva fluidity, were investigated. In addition, to have wider information about the apelinergic system function, presence and localization of both apelin and its receptor were studied. Findings suggest that the different mechanical stimuli in the mouth linked to different feed physical forms likely allow one to diverse physiological behavior of the pig mandibular gland. The intense chewing activity linked to the highest feed compaction and hardness promotes an increase in pig mandibular gland secretion. In addition, saliva becomes more fluid and richer in acid glycoconjugates in order to better lubricate the bolus and protect the mouth mucosae. The apelinergic system is likely involved in the above modifications enhancing both the fluidity and the quantity of serous saliva by the pig mandibular gland.

Abstract

A study was performed on the mandibular gland obtained from growing pigs enrolled in a wide research project aiming to test the effects of different feed physical forms on animal health, production and welfare. We used 48 pigs fed for four weeks with different dietary treatments based on different grinding intensities and compactions of the same diet, namely coarsely ground meal (CM), finely ground pelleted (FP) and coarsely ground pelleted (CP) diets. Samples were analyzed by conventional histochemistry to identify the glycohistochemical profile and by immunohistochemistry to localize aquaporin 5, apelin and apelin receptor. Statistical elaborations were performed using the Stats R-package, version 3.5.3. Pig mandibular gland adenomere increased both the quantity and acidity of produced glycoconjugates from CM to FP and CP diets. This probably calls forth higher watery saliva, thus promoting a better feed softening facilitating the amalgamation of the bolus. Mandibular gland increased aquaporin 5 positivity in the CP diet, supporting the hypothesis of an augmented demand for water. Based on apelin/receptor localization, it was hypothesized that in pig mandibular gland the apelinergic system likely performs an endocrine control on the demilunes activity and a paracrine control on ducts, facilitating the production of a more fluid saliva.

A Detailed Study of Rainbow Trout (Onchorhynchus mykiss) Intestine Revealed That Digestive and Absorptive Functions Are Not Linearly Distributed along Its Length

Simple Summary

Aquaculture is the fastest growing food-producing sector due to the increase of fish intended for human consumption. However, aquaculture growth generates concerns, since carnivorous fish are extensively fed using fish-meal and fish-oil. This constitutes a severe limit to the aquaculture industry, questioning its sustainability. Consequently, alternative feeds are continuously searched through extensive in vivo feeding trials. Undoubtedly, to evaluate their impact on the gastrointestinal tract health, detailed knowledge of the intestine morphology and physiology is required. To date, extensive studies have been performed in several livestock species; however, available information on fish is limited nowadays, most importantly because their alimentary canal is able to easily adapt to external stimuli, and their intestinal morphology is affected by external factors. Therefore, it is essential to establish accurate reference values, especially along the productive cycle of animals raised in standardized conditions. Here, we performed a detailed characterization of the epithelial cells lining the intestinal mucosa in rainbow trout along the first year of development. We studied the absorptive and secretory activity as well as its ability to self-renewal. Our results indicate that, in this species, both digestive and absorptive functions are not linearly distributed along the intestinal length.

Abstract

To increase the sustainability of trout farming, the industry requires alternatives to fish-based meals that do not compromise animal health and growth performances. To develop new feeds, detailed knowledge of intestinal morphology and physiology is required. We performed histological, histochemical, immunohistochemical and morphometric analysis at typical time points of in vivo feeding trials (50, 150 and 500 g). Only minor changes occurred during growth whereas differences characterized two compartments, not linearly distributed along the intestine. The first included the pyloric caeca, the basal part of the complex folds and the villi of the distal intestine. This was characterized by a significantly smaller number of goblet cells with smaller mucus vacuoles, higher proliferation and higher apoptotic rate but a smaller extension of fully differentiated epithelial cells and by the presence of numerous pinocytotic vacuolization. The second compartment was formed by the proximal intestine and the apical part of the posterior intestine complex folds. Here we observed more abundant goblet cells with bigger vacuoles, low proliferation rate, few round apoptotic cells, a more extended area of fully differentiated cells and no pinocytotic vacuoles. Our results suggest that rainbow trout intestine is physiologically arranged to mingle digestive and absorptive functions along its length.