Immunostimulatory and Antibacterial Effects of Cannabis sativa L. Leaves on Broilers

The aim of this study was to evaluate the effect of dried Cannabis sativa L. leaves as a phytogenic mixture added to broiler feed on CD4+ and CD8+ T lymphocyte subpopulations, Newcastle disease virus (NDV) antibody titres, and the presence of E. coli in faecal samples. The study was conducted on 100 male Ross 308 broilers, divided into four groups of 25 broilers, for a 42-day research period. The groups were housed separately in boxes on a litter of softwood shavings and were fed starter mixture from day 1 to day 21 and finisher mixture from day 22 to day 42. Industrial hemp (C. sativa) was grown in the Crkvina area, Croatia (latitude: 45°18'46.8″ N; longitude: 15°31'30″ E). The hemp leaves were manually separated, sun-dried, and ground to a powder. The mixture offered to the control group did not contain cannabis leaves, whereas the three experimental groups received mixtures containing mixed cannabis leaves in a quantity of 10 g/kg, 20 g/kg, or 30 g/kg (E_10, E_20, and E_30, respectively). The mean NDV antibody level was uniform in all study groups until post-vaccination day 14 and increased comparably with time. The percentage of CD4+ and CD8+ lymphocytes in the peripheral blood subpopulation showed statistically significant differences (p < 0.001) in the E_20 group as compared with the control group and both the E_10 and E_30 groups throughout the study period. As the broiler age increased, the CD4+-to-CD8+ ratios also increased and were statistically significant (p < 0.0001) on day 42 in all experimental groups as compared to the control group. Comparing the control group with the experimental groups indicated that the bacterial count was lower in broiler groups having received feed with the addition of 20 g/kg and 30 g/kg C. sativa leaves. In conclusion, the C. sativa leaves were found to elicit a favourable immunomodulatory effect on cell-mediated and humoral immune responses in broilers via increased CD4+ and CD8+ lymphocyte subpopulations and higher CD4+:CD8+ cell ratios, thus indicating enhanced immune function capacity. In addition, C. sativa leaves may have complementary effects on the broiler post-vaccination immune response, increase broilers' resistance to infectious diseases, reduce the effect of stress associated with vaccination, and improve broiler health and welfare.

Evaluation of the prophylactic potential of non-enterotoxigenic Escherichia coli (non-ETEC) vaccine immunization and dietary mannan oligosaccharide competitive exclusion benefits against ETEC infections in weaned pigs

Enterotoxigenic Escherichia coli (ETEC) strains expressing F4 and F18 fimbriae are the most common causative agents of post-weaning diarrhoea (PWD) in pigs. The growing global restriction on the use of antibiotics in food animals has encouraged research into the development of nutritional and feeding strategies as well as vaccination against PWD. The aim of this study was to evaluate the efficacy of a live oral F4ac+ F18ac+ non-ETEC vaccine candidate (VAC) to stimulate gut and systemic cellular immunity in 4-week old pigs over 5 weeks following immunization. The onset and duration of protective immunity against on-farm occurring PWD, growth performance, diarrhoea scoring and mortality, as well as the phenotypic proportions of immune cells, were determined. Faecal and ileal samples were taken for determining the microbial composition or phenotyping of naïve/memory T cells. Also, the effect of prebiotic supplement mannan oligosaccharide (MOS) in the prevention of small intestinal colonization by ETEC, and its potential adjuvanticity in combination with the vaccine (VAC+MOS) were assessed. The pigs supplemented with MOS or that received VAC had significantly higher body weight (BW) (P<0.05) on Day 14, whereas the VAC+MOS treated pigs had significantly lower BW on Day 35. Treatment with VAC+MOS resulted in considerably reduced clinical PWD, in particular the incidence and severity of diarrhoea and mortality. The total bacterial load in the ileum was much lower in the pigs from all 3 principal groups (MOS, VAC, and VAC+MOS) than in the control (CON) group (19 x 107, 17 x 107 and 12 x 107 vs. 23 x 108 CFU/mL, respectively) on Day 35. The pigs from the principal groups had significantly higher proportions of tested immune cells (P<0.05) on Days 28 and 35. The localization and frequency of naive CD45RA+ and memory CD45RC+ T lymphocytes indicated their different distribution patterns within particular tissue structures, such as the villi, crypts, epithelium, lamina propria and areas (interfollicular follicular and Peyer’s patches) of ileal mucosa. This may indicate their different functions in intestinal immune responses to intraluminal microbes and their products, vaccinal immunogens and/or immunomodulators/adjuvants. To conclude, active mucosal immunity is needed to protect pigs against PWD. Hence, oral vaccination of pigs against both F4 and F18 ETEC, in combination with prebiotic supplementation represents a sustainable, practical and effective approach in PWD control.

[IVO HORVAT, BOTANIST (1897 - 1963), WORK AT THE DEPARTMENT OF BOTANY OF THE FACULTY OF VETERINARY MEDICINE AT THE UNIVERSITY OF ZAGREB]

Professor Ivo Horvat, a world-renowned Croatian scientist, botanist, and university teacher, was born in Čazma on October 7, 1897. After finishing the Classical Gymnasium in Zagreb in 1916, he graduated from the University of Zagreb, Faculty of Philosophy in 1920 and obtained his Ph.D. in botany on July 31, 1920. From his invaluable scientific and educational heritage, we have selected out for this occasion only a small part dedicated to the period from June 11, 1947 to April 23, 1963, in which Prof. Horvat worked at the Faculty of Veterinary Medicine, University of Zagreb. He worked in a wide range of both natural and biomedical veterinary sciences: from systematic botany, ecology, and environmental protection to the study of phylogeny, floristic, and vegetation research, including vegetation mapping and scientific-organizational work. Following the bibliographic and archival sources of the original documents, the given data represent a brief overview of Prof. Horvat’s contribution to phytocoenological work and an overview of scientific and educational heritage with an emphasis on the years spent at the Faculty of Veterinary Medicine, University of Zagreb.

The influence of season and age on the levels of lipids, lipoproteins and enzymes in the serum of Lička pramenka sheep

This study aimed to identify seasonal and age related variability in triglycerides (TRI), paraoxonase (PON), stimulated PON (PON I) and cholesterol (CHOL, HDL, LDL) in extensively reared Lička pramenka sheep. The study was conducted 30 randomly chosen non-gravid Lička pramenka sheep on an extensive farm, grouped into three age groups in the Karlovac County, Croatia. Blood was collected by venepuncture of the jugular vein, twice in one year - the first sampling in spring (April) and the second in autumn (October). The results showed that age had no significant effect on any of the investigated indicators, while seasonality significantly affected five out of the six parameters examined. Significantly higher levels of serum lipid components in autumn can be explained by the influence of the traditional way of rearing and feeding Lička pramenka sheep. Furthermore, the results of PON I in all three age groups showed that the sheep are well adapted to the environment and to the rearing system. Future research should be carried out on higher number of farms, and should include more sheep in order to determine objective benchmarks for serum lipids and the enzymes connected to those lipids.

The influence of exogenous melatonin on antioxidative status in seminal plasma and spermatozoa in French Alpine bucks during the nonbreeding season

Research data regarding exogenous melatonin effects on buck semen antioxidative status during the breeding and nonbreeding seasons are scarce or missing. The aim of this study was to investigate the effect of melatonin implants on the activity and ratios of antioxidative enzymes and on malondialdehyde concentrations in the seminal plasma and spermatozoa of French Alpine bucks during the 3 mo of the nonbreeding season. Two groups of randomly assigned bucks were either treated with melatonin (n = 6) or served as controls (n = 6). Semen samples were collected weekly, seminal plasma was separated from spermatozoa, and activities of glutathione peroxidase (GSH-Px), glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT), and the concentration of malondialdehyde were determined. The melatonin-treated bucks had significantly higher CAT/SOD and GSH-Px/SOD ratios, but a significantly lower GR/GSH-Px ratio in seminal plasma and spermatozoa during the different periods of the nonbreeding season. In conclusion, exogenous melatonin influenced the activities of all ratios and some single antioxidative enzymes tested in bucks' seminal plasma and spermatozoa. Here we provide the first evidence derived from an intervention, that is, melatonin treatment, which affects antioxidative enzymes ratios in the semen of bucks, and could thus be recommended as an indicator of oxidative stress severity and antioxidative status of semen.

Analysis of 12 X-chromosomal markers in the population of central Croatia

Investigator® Argus X-12 Kit is a commercially available set that allows simultaneous PCR amplification of 12 X-STR markers belonging to four linkage groups (LG). To assess the forensic efficiency of these markers for the population of central Croatia and consequent applicability in routine forensic casework, DNA from 200 blood samples of unrelated donors (100 female and 100 male) was amplified by Investigator® Argus X-12 Kit and analyzed by capillary electrophoresis. Statistical computations based on allele and haplotype frequencies for LG1 - LG4 were performed using Arlequin 3.5 software and on-line tool available at ChrX-STR.org. In female samples, all X-STR markers were in Hardy-Weinberg equilibrium (HWE). The most informative marker for central Croatia population was DXS10135 with polymorphism information content (PIC) 0.9296. The least polymorphic locus was DXS8378 (PIC=0.6363). Power of discrimination (PD) varied from 0.6968 to 0.9336 in male and from 0.8476 to 0.9916 in female samples. Combined PD exceeded 0.999999999 in both men and women. In male samples, linkage disequilibrium (LD) test revealed significant association (P=0.0000) of one marker pair in LG4 and two marker pairs in LG3. Portion of observed haplotypes in the number of possible haplotypes varied from 2.86% to 7.47% across all LGs. LG1 was the most informative with haplotype diversity (H) 0.9972. High PD of all analyzed markers exhibited for central Croatia population confirms suitability of Investigator® Argus X-12 for forensic pertinence. Moreover, results of this study will be included in establishing a national reference X-STR database based on 12 X-STR loci, which is necessary for the correct interpretation of the forensic casework results.

Gleaning a Human DNA Profile from Trace Swabs Collected from Animal Hairs

Animal hairs are an apt surface for retention of forensic trace epithelial samples. The aim of this study was threefold: to evaluate different methods of sample collection (moistened and dry swabs) and DNA extraction (Chelex® 100 method, Qiagen EZ1® DNA Investigator Kit), as well as to examine the morphological differences of hair fibres between two species (dog, sheep) and their ultimate impact on sample collection and processing. Our preliminary findings suggest that the use of EZ1® DNA Investigator Kit yields donor DNA profiles of higher quality. The results of different sample collection methods have shown intraspecific variations that require further investigation. The ability of retention and subsequent extraction of trace DNA appears to be similar between the two species, despite significant morphological differences between their coat hairs.

Synthetic vs natural scaffolds for human limbal stem cells

Aim

To investigate the impact of synthetic electrospun polyurethane (PU) and polycaprolactone (PCL) nanoscaffolds, before and after hydrolytic surface modification, on viability and differentiation of cultured human eye epithelial cells, in comparison with natural scaffolds: fibrin and human amniotic membrane.

Methods

Human placenta was taken at elective cesarean delivery. Fibrin scaffolds were prepared from commercial fibrin glue kits. Nanoscaffolds were fabricated by electrospinning. Limbal cells were isolated from surpluses of human cadaveric cornea and seeded on feeder 3T3 cells. The scaffolds used for viability testing and immunofluorescence analysis were amniotic membrane, fibrin, PU, and PCL nanoscaffolds, with or without prior NaOH treatment.

Results

Scanning electron microscope photographs of all tested scaffolds showed good colony spreading of seeded limbal cells. There was a significant difference in viability performance between cells with highest viability cultured on tissue culture plastic and cells cultured on all other scaffolds. On the other hand, electrospun PU, PCL, and electrospun PCL treated with NaOH had more than 80% of limbal cells positive for stem cell marker p63 compared to only 27%of p63 positive cells on fibrin.

Conclusion

Natural scaffolds, fibrin and amniotic membrane, showed better cell viability than electrospun scaffolds. On the contrary, high percentages of p63 positive cells obtained on these scaffolds still makes them good candidates for efficient delivery systems for therapeutic purposes.