Bela Njari

A royal jelly as a new potential immunomodulator in rats and mice

In order to study a possible immunomodulatory effect of the royal jelly (RJ) secreted by mandibular and hypopharingeal glands of the worker honeybee (Apis mellifera Linné.) we have used a well established rodent model. The CBA mice were given s.c. 0.1 ml of RJ, 7 days before, or immediately after, the immunization with sheep red blood cells (SRBC). The Y59 rats received i.m. 0.4 ml or i.v. 0.025 ml of RJ once or twice at 7 day intervals. Serum levels of total proteins and immunoglobulins in the rats that received RJ once or twice within a 2-week-period were significantly lower (P < or = 0.05) as compared with the nontreated animals. In mice which were immunized with 4 x 10(8) of SRBC 7 days after the application of RJ the number of plaque forming splenocytes was significantly higher (P < or = 0.05) than that in the controls. Both the weight of inguinal lymph node and the number of peripheral blood lymphocytes were increased (P < or = 0.05) in RJ-treated mice 3 or 5 days after the immunization, respectively. Neutrophils were decreased (P < or = 0.05) in the mice that were killed 5 or 10 days after the RJ treatment. Overall these results indicate that RJ exhibited immunomodulatory properties by stimulating antibody production and immunocompetent cell proliferation in mice or depressing humoral immune functions in rats. Both phenomena, though species-related in this model, could probably be reversed by changing the dose or the route of RJ application.

Risk assessment of streptomycin and tetracycline residues in meat and milk on Croatian market

In addition to biological hazards like bacteria, viruses, parasites, the occurrence of chemical hazards is another characteristic of modern food production. The use of veterinary medicines in intensive production of animals is conditio sine qua non so it is impossible to avoid in full the presence of their residues in food. This paper presents quantitative risk assessment of streptomycin and tetracycline based on acceptable daily intake, daily consumption of milk and meat in Croatia (0.222 and 0.126 kg/person, respectively) and residues of these two veterinary drugs in this type of food. The median value for streptomycin in milk and meat was 11.50 and 38.00 μg/kg, respectively (milk: average: 15.57 μg/kg; range from 0 to 73.82 μg/kg; meat: average 44.14 μg/kg; range from 0 to 278.35 μg/kg). The median value for tetracycline in milk and meat was 1.50 μg/kg (milk: average 1.5 μg/kg; range, from 0 to 4.26 μg/kg; meat: average 1.62 μg/kg; range from 0 to 5.35 μg/kg). Based on the median value it can be concluded that the estimated daily intake of streptomycin and tetracycline through milk and meat in Croatia is low (streptomycin: 7.33 μg/person/day; tetracycline: 0.52 μg/person/day), and the risk is assessed as negligible.

Experimental model of enterotoxigenic Escherichia coli infection in pigs: potential for an early recognition of colibacillosis by monitoring of behavior

The hypothesis that altered behavior is a sign for an early recognition of disease was tested. The experiment was conducted to evaluate the behavioral patterns of pigs in a model of postweaning colibacillosis. Twenty-five weaned pigs (from a herd that was previously found to be highly susceptible to F4+ Escherichia coli strains) were randomly assigned into 5 groups, kept in isolated pens under the controlled ambiental conditions. One day after weaning, the pigs from three groups were intragastrically inoculated (via orogastric tube) with either F4ac+ (1466 or 2407) or F4- (1467) nonenterotoxigenic E. coli (non-ETEC) strains, respectively. The pigs from the fourth group were inoculated with F4ac+ ETEC strain M1823 and the remaining 5 pigs that received broth containing 1.2% sodium bicarbonate were kept as noninoculated controls. The pigs were examined daily and the frequency and duration of their behavioral patterns, such as eating, drinking, lying, standing, urinating, defecating, rooting and playing were monitored for 300 h during a period of 10 days. In this model, three conditions were also observed in F4-susceptible pigs: (1) acute fatal diarrheal disease; (2) moderate diarrhea and weight loss and (3) no diarrhea and weight loss. The incidence (both frequency and duration) of defecating was significantly higher (P < 0.05) in pigs inoculated with F4ac+ ETEC strain M1823 as compared to that of noninoculated (control) pigs. Pigs inoculated with F4ac+ non-ETEC strain 1466 had a significantly lower frequency of eating (P < 0.05) and frequency/duration of drinking (P < 0.05) than did the controls. The 1466-inoculated pigs, had an increased diarrhea score, but frequency/duration of defecating was not significantly different. Pigs inoculated with F4ac+ non-ETEC strain 2407 spent more time in lying (P < 0.05) than did noninoculated pigs. Conversely, the pigs that received F4- non-ETEC strain 1467 laid shorter (P < 0.05) and ate/drank less frequently (P < 0.05) than the controls. It was concluded that the changed occurrence of defecating and eating in pigs that were inoculated with either F4ac+ ETEC (M1823) or non-ETEC (1466) strain. respectively, was consistent with the pending clinical disease, i.e. postweaning colibacillosis.

Prevalence of Cysticercus bovis in slaughtered cattle determined by traditional meat inspection in Croatian abattoir from 2005 to 2010

SummaryThe aim of this work was to evaluate the presence of Cysticercus bovis of slaughtered cattle in a Croatian slaughterhouse between 2005 and 2010. In total, 203 166 carcasses and organs were examined, of which in 228 C. bovis was found (0.11 %). The highest number of cysticercosis was found in cows (0.69 %, n = 13 605), then in steers (0.093 %; n = 134 212), and the lowest in calves (0.014 %; n = 55 349). Among the 228 positive specimens, 129 (56.57 %) came from rural estates and 99 (43.43 %) from farms. The ratio of invaded steers from rural estates (n = 2 790) and from farm breed (n = 131 422) was 1.075 %: 0.064 %, calves (n = 316 and n = 55 033) 0.316 %: 0.012 %, and cows (n = 8 985 and n = 4 620) 097 %: 0.15 %. The number of cysticercosis invaded cattle decreased from the initial 0.37 % to 0.07 %. Despite low prevalence, we consider that each positive result requires an individual epidemiologic study in order to decrease the risk even more.

The antimicrobial effect of lactobacilli on some foodborne bacteria.

The aim of this study was to determine the inhibitive effect of eleven lactobacilli strains from traditional fermented sausages on Listeria (L.) monocytogenes NCTC 10527, three strains of L. monocytogenes from food, L. welshimeri, Yersinia (Y.) enterocolitica, Pseudomonas (P.) aeruginosa, Staphylococcus (S.) aureus NCBF 1499, Salmonella Enteritidis and Salmonella spp. by use of the agar spot and agar diffusion tests. The most sensitive indicator bacteria were L. monocytogenes 1 (inhibited by ten of eleven strains of lactobacilli) and L. monocytogenes NCTC 10527 (8/11), whilst the most resistant was L. welshimeri (3/11). Six lactobacilli strains inhibited Salmonella spp., five P. aeruginosa and four inhibited the growth of Y. enterocolitica, S. aureus and Salmonella Enteritidis. The broadest spectrum of inhibition was confirmed for Lactobacillus (Lb.) paracasei subsp. paracasei, and the narrowest for Lb. curvatus. The preliminary results indicate a significant antimicrobial activity of selected lactobacilli, which is one of the important characteristics of the potential functional starter cultures.

Low motivation and unawareness in small farmers as an obstacle for implementation of the EU pig welfare rules

Abstract Using semi-structured interviews, Croatian pig farmers and institutional stakeholders were asked about their intentions to improve pig welfare, future perspectives, opinions and communication efforts on the EU pig welfare directives. While full-time family farmers (FFF) and employees at farm enterprises (EFE) expressed interest in improving pig welfare on their farms as a prerequisite for increasing competitiveness in the future, part-time family farmers (PFF) were not interested in pig welfare because they did not want to increase productivity and feared for their existence. Communication between institutional stakeholders and FFF with more than ten sows is best stablished, whereas communication with EFE is more via private consultants and communication with PFF is lacking. As Croatia is today counting over 85% farms as production units with up to 10 sows covering 75% of whole pig production, these results represent considerably important indicators of necessity to approach this population of farmers.

Influence of housing systems on stillbirth and mortality rate in preweaning pigs farrowed by different gilt breeds

Abstract The aim of this paper was to investigate the influence of housing systems on stillbirth and mortality rate in preweaning pigs farrowed by different gilt breeds. The investigation included first farrowings of 225 Large White (LW) gilts, 297 Swedish Landrace (SL) gilts and 260 crossbreed gilts (LWxSL) in the period of five years. Despite of positive influence of straw through decreased number of stillborn pigs, especially in LW gilts, in further process of production until weaning, less appropriate microclimatic conditions developed in farrowing houses with straw, especially if accompanied with poor ventilation, can result with higher number of perished pigs and lower number of weaned pigs. Most sensible to unsuitable microclimatic conditions in straw bedded farrowing houses, according to the number of perished pigs before weaning, were the pigs from SL gilts, while the pigs from crossbreed gilts LWxSL were the most resistant. These results suggest that adding straw requires special attention on influence of such production on microclimate conditions in pigs’ biozone in order to maintain its initial benefits in the time of farrowing through the whole preweaning period, especially in pure breeds of gilts.

The impact of frozen storage duration on physical, chemical and microbiological properties of pork

The aim of the present study was to evaluate the effect of frozen storage duration (3, 6, 9, 12, 15, 18 months) on physical, chemical and microbial properties of pork in three cuts (loin, ham, and belly rib). During frozen storage, significant alterations in physical and chemical parameters were observed through the increase of the total exudate, pH and lightness (L*), and a decrease of shear force and yellowness (b*). Water content in ham samples decreased, while protein content increased. The lipid oxidation (TBA) values in loin and ham samples increased for up to fifteen months of frozen storage, after which they decreased. The proportion of saturated fatty acids in frozen samples was significantly higher than in fresh meat. The total amount of Enterobacteriaceae, S. aureus and Pseudomonas spp. decreased during frozen storage, indicating that freezing may reduce the number of bacteria found in meat. Frozen pork microflora did not change after eighteen months of storage.

The composition and properties of jenny milk

Uzgoj magaraca i proizvodnja magareceg mlijeka sve je cesca, narocito u obiteljskim poljoprivrednim gospodarstvima na podrucju Istre i Dalmacije, ali i kontinentalne Hrvatske. U radu je istražen osnovni kemijski i masnokiselinski sastav, broj somatskih stanica te senzorska svojstva magareceg mlijeka. Sveukupno je analizirano 11 uzoraka mlijeka magarica dviju pasmina podrijetlom s gospodarstava na podrucju Zagrebacke i Istarske županije. Udio masti bio je izrazito nizak i iznosio je najvise 1, 16 %, dok je prosjecna kolicina masti u mlijeku istarskih magarica bila 0, 14 %, odnosno 0, 69 % u dalmatinskih magarica. Prosjecna kolicina bjelancevina iznosila je 1, 29 %, a laktoze 6, 5 %. Mlijeko dalmatinskih magarica sadržavalo je 3, 8 log10 mL-1 somatskih stanica cija je vrijednost bila manja u mlijeku istarskih magarica (3, 2 log10 mL-1). Istovremeno, utvrđen je veci ukupni broj leukocita (4, 9-5, 3 x 109/L) u uzorcima mlijeka istarskih magarica u odnosu na mlijeko dalmatinskih magarica (najvise 5, 1 x 109/L). Masnokiselinski sastav pokazao je da udjel zasicenih masnih kiselina (SFA) u mlijeku istarskih magarica iznosi 70, 45 % a dalmatinskih 59, 92 %. Mononezasicene masne kiseline (MUFA) prosjecno su bile zastupljene s 21, 23 % i 24, 61 %, a polinezasicene masne kiseline (PUFA) s 8, 31 % i 15, 46 % u istarskih i dalmatinskih magarica. Ukupni omjer zasicenih prema nezasicenim masnim kiselinama iznosio je od 0, 37 do 0, 72 i bio je niži u uzorcima mlijeka istarskih magarica. Magarece mlijeko odlikuje nizak sadržaj masti i visok sadržaj laktoze, masnokiselinski sastav s povoljnim omjerom zasicenih i nezasicenih masnih kiselina. Broj somatskih stanica u mlijeku je niži u odnosu na mlijeko drugih domacih životinja.

Prevalence of Thermotolerant Campylobacter spp. in Chicken Meat in Croatia and Multilocus Sequence Typing of a Small Subset of Campylobacter jejuni and Campylobacter coli Isolates

In order to detect thermotolerant Campylobacter spp., 241 samples of fresh chicken meat, at retail in Croatia, were analysed according to a standard method, followed by biochemical test and molecular polymerase chain reaction/restriction enzyme analysis for exact species determination. Campylobacter spp. prevalence was 73.86%. Campylobacter jejuni and Campylobacter coli were isolated from 53.53 and 15.35% of the samples, respectively. In 4.98% of isolates thermotolerant Campylobacter spp. were not determined. The multilocus sequence typing method was used to evaluate genetic diversity of eight Campylobacter jejuni and four Campylobacter coli isolates. To our knowledge, these results of genotyping provided the first data on the presence of sequence types (STs) and clonal complexes (CCs) of Campylobacter jejuni and C. coli isolates in Croatia. By applying the multilocus sequence typing, a new allele of tkt gene locus was discovered and marked tkt508. The C. jejuni ST 6182 and C. coli ST 6183 genotypes were described for the first time, and all other identified genotypes were clustered in the previously described sequence types and clonal complexes. These findings provide useful information on the prevalence and epidemiology of Campylobacter jejuni and C. coli in Croatia.