Feeding of carob (Ceratonia siliqua) to sheep infected with gastrointestinal nematodes reduces faecal egg counts and worm fecundity

The present study explored the anthelmintic effects of condensed tannins (CT) in carob (Ceratonia siliqua) pods fed to sheep against gastrointestinal nematodes. Three independent in vivo trials tested whether i) carob pod (CaBP)-containing feed had an anthelmintic effect and if yes, which was the optimal concentration in the diet; ii) whether this effect could be attributed to tannins through the polyethylene glycol (PEG) test and iii) whether there were any synergistic effects when combined with another tannin-containing feed (e.g. sainfoin). In all trials 6-month old nematode-naive lambs, experimentally infected with both Haemonchus contortus and Trichostrongylus colubriformis, were used. Faecal egg counts (FEC) were performed regularly and at the end of each trial adult worm counts (AWC) and female worm fecundity were recorded. In trial 1, 35 lambs (five groups of seven lambs) were fed different CaBP concentrations ranging from 0% to 12 % w/w. FEC declined up to 39.2 % only in the group fed with 12 %CaBP, while a declining trend (P < 0.06) was demonstrated for the AWC of T. colubriformis, which was associated with the increasing concentration of CaBP in feed. Female worm fecundity was reduced in groups fed CaBP for both parasites, however this was only significant for H. contortus (P < 0.001), in a dose dependent manner. In trial 2, four groups of six infected lambs each were used, which received the carob diets CaBP or CaBP + PEG, and the tannin-free diets with or without PEG (C or C + PEG). Results showed that FEC of Groups C, C + PEG, and CaBP + PEG were comparable throughout the trial, while the group receiving only CaBP showed lower FEC from DAY 25 onwards. AWC showed a reduction (67.7 %) only for H. contortus (P < 0.03). Reversal of the anthelmintic effect of CaBP after PEG administration suggested that CT contributed to the anthelmintic action. However, no effect of CaBP was observed on T. colubriformis AWC and on female worm fecundity for both species. Finally, for trial 3 four groups of six lambs each received a diet based on CaBP, sainfoin (S) or a combination (CaBP + S) and were compared to a control (C) diet of lucerne. On DAY 37 FEC values in groups CaBP + S and S tended to be lower compared to the two other groups (C, CaBP), while for AWCs no significant differences were observed for both parasites. The fecundity of H. contortus and T. colubriformis demonstrated significant differences between the treated and control groups, with lower values in the animals receiving CaBP + S. Overall, the results supported the hypothesis that carob had an anthelmintic effect due to its CT, but there was no clear indication of a synergistic effect with sainfoin.

Coccidiostatic effects of tannin-rich diets in rabbit production

The potential anti-eimerial effect of tannin containing resources such as sainfoin and carob in rabbits was tested on does at pre-weaning and to growing rabbits in their feed. The trial began at parturition (D0), when 24 does and their litters were assigned into three groups. They were fed either with a control (Group CO), a carob (containing 10% carob pods meal) (Group CP) or a sainfoin diet (containing 34% dehydrated sainfoin pellets) (Group SA). All diets were made isoproteic and isoenergetic and also balanced for crude fibre but differed by their tannin content. Weaning occurred at D37, and growing rabbits remained in the same cage until D51. Then, they were transferred to fattening cages until the end of the trial (D104) and slaughtering. Weight gain of young rabbits among the three groups (mean = 31.2 g/day) did not differ statistically. The mortality rates were 10% (SA), 15% (CP) and 20% (CO), respectively, but the differences were not statistically significant. Post-weaning economical feed conversion ratio (FCR) was reduced between rabbits of group SA compared to CO and CP groups. Faecal oocyst count (FOC) in group SA was 60% lower than in CO and CP groups. Areas under the curve (AUCs) calculated between sampling days and FOC, after transfer to fattening cages, was 62% lower in group SA than in CO and CP groups. The main Eimeria species identified (from D59 to D83) was Eimeria magna (53% of oocysts). AUCs for E. magna did not differ according to diet. In conclusion, the diet containing sainfoin reduced oocyst excretion of Eimeria spp. by 60%, and improved the economical FCR.

Abundance, zoonotic potential and risk factors of intestinal parasitism amongst dog and cat populations: The scenario of Crete, Greece

Background

The objectives of this study were to evaluate the prevalence and infection intensity of intestinal parasites in different dog and cat populations in Crete, Greece, estimate the zoonotic risk and identify risk factors.

Methods

Faecal samples from shelter, household and shepherd dogs and shelter and household cats were analyzed using sedimentation/flotation techniques. Giardia and Cryptosporidium were detected by a quantitative direct immunofluorescence assay (IFA). PCR and sequencing was performed to evaluate the zoonotic potential of Giardia and Cryptosporidium positive samples.

Results

Totals of 879 dog and 264 cat faecal samples were examined. In dogs, the overall prevalence was 25.2% (CI: 22.4–28.1) for Giardia spp.; 9.2% (CI: 7.3–11.1) for Ancylostoma/Uncinaria spp.; 7.6% (CI: 5.9–9.4) for Toxocara spp.; 5.9% (CI: 4.4–7.5) for Cryptosporidium spp.; 4.6% (CI: 3.2–5.9) for Cystoisospora spp.; 2.7% (CI: 1.7–3.8) for Toxascaris leonina; 1.7% (CI: 0.9–2.6) for Capillaria spp.; 0.8% (CI: 0.2–1.4) for taeniid eggs; 0.2% (CI: 0–0.5) for Dipylidium caninum; and 0.1% (CI: 0–0.3) for Strongyloides stercoralis. In cats, the prevalence was 20.5% (CI: 15.6–25.3) for Giardia spp.; 9.5% (CI: 5.9–13.0) for Cystoisospora spp.; 8.3% (CI: 5.0–11.7) for Toxocara spp.; 7.6% (CI: 4.4–10.8) for Ancylostoma/Uncinaria spp.; 6.8% (CI: 3.8–9.9) for Cryptosporidium spp.; 4.2% (CI: 1.8–6.6) for Capillaria spp.; 0.8% (CI: 0–1.8) for taeniid eggs; and 0.4% (CI: 0–1.1) for Hammondia/Toxoplasma. Concerning the risk factors evaluated, there was a negative association between age and Giardia infection and between age and T. leonina infection intensity for dogs. Sequencing results revealed the presence of mainly animal-specific G. duodenalis assemblages C and D in dogs and assemblages F, C and BIV-like in cats, with only a limited number of (co-)infections with assemblage A. As for Cryptosporidium, the dog-specific C. canis and the pig-specific C. scrofarum were detected in dogs and the cat-specific C. felis was detected in cats.

Conclusions

High levels of parasitism in both dogs and cats were recorded. Giardia was the most prevalent parasite in all dog and cat populations except for shepherd dogs. Genotyping results suggest a limited zoonotic risk of Giardia and Cryptosporidium infections from dogs and cats in Crete. Taeniid eggs were more prevalent in shepherd dogs suggesting access to carcasses and posing a threat for cystic echinococcosis transmission. Infection rates of Toxocara spp. in both dogs and cats show that companion animals could be a significant source of infection to humans.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-017-1989-8) contains supplementary material, which is available to authorized users.

The occurrence and genetic characterization of Cryptosporidium and Giardia species in foals in Belgium, The Netherlands, Germany and Greece

Faecal samples were collected from foals between the age of 1 week and 6 months in Belgium, The Netherlands, Germany and Greece. A quantitative direct immunofluorescence assay based on the commercial MERIFLUOR Cryptosporidium/Giardia kit was performed to evaluate the presence of (oo) cysts. Parasite positive samples were genotyped, based on the 18S ribosomal DNA gene and the heat shock protein (HSP70) gene for Cryptosporidium and on the β-giardin gene and the triose phosphate isomerase (TPI) gene for Giardia. In total, 134 foals from Belgium, 44 foals from The Netherlands, 30 foals from Germany and 190 foals from Greece were examined. No Cryptosporidium oocysts were identified in faecal samples from foals in Germany and The Netherlands. In Belgium and Greece, 4.5% and 1.1% of the foals examined were Cryptosporidium positive, respectively, all with a low oocyst excretion ranging from 100 to 2450 oocysts per gram of faeces. For Giardia, 14.2%, 11.4%, 10.0% and 11.6% of the foals in Belgium, The Netherlands, Germany and Greece, respectively, were found to excrete cysts, with a range of 50 up to 4,000,000 cysts per gram of faeces. Younger animals secreted significantly more Giardia cysts than older horses (p<0.05), but no significant correlation between Giardia infection and diarrhoea was observed. Most Giardia positive samples belonged to assemblage AI and/or BIV, but also assemblage E was detected in two samples. Together with the identification of Cryptosporidium horse genotype, this suggests only a low risk for zoonotic transmission.

Anthelmintic effect of carob pods and sainfoin hay when fed to lambs after experimental trickle infections with Haemonchus contortus and Trichostrongylus colubriformis

The aim of the study was to compare the in vivo anthelmintic activity of sainfoin hay (Onobrychis viciifolia) and carob pod meal (Ceratonia siliqua) against gastrointestinal nematodes. Seven days before infection, 64 naive lambs were assigned to four different groups: Group S received sainfoin hay and group CAR was fed with carob pods. The remaining lambs received lucerne hay (Medicago sativa) and were assigned to positive (non-treated, NT) and negative (treated, T) control groups (treatment with albendazole). On day 0, lambs were artificially trickle infected for 6 weeks, with a mixture of infective larvae of Haemonchus contortus and Trichostrongylus colubriformis. Parasitological and pathophysiological parameters were measured repeatedly during the 2-month study. Compared to the NT group, decreases in egg excretion were observed in the CAR and S groups with significant differences only found for sainfoin (p < 0.05). At necropsy, group S showed decreases in the total worm numbers of both nematode species with significant differences for H. contortus. In contrast, no differences were noticed for the CAR group. Compared to the NT group, lower values for fecundity of female H. contortus were found in the S and CAR groups, however differences were non-significant. No differences in body weight gains were found between groups. Consistent results were found showing significantly higher packed cell volume (PCV) values in the T and S groups compared to NT and CAR groups. Overall, these results confirm a positive effect associated with the feeding of lambs with tanniniferous resources on host resilience (PCV values) and against gastrointestinal parasitic nematodes by affecting some biological traits of worm populations (e.g. eggs per gram of faeces and worm numbers). However, the anthelmintic effects differed between the two tannin-containing resources, which might be associated with the quantity and/or quality of secondary metabolites (condensed tannins and/or other polyphenols).

Occurrence and molecular characterization of Giardia duodenalis and Cryptosporidium spp. in sheep and goats reared under dairy husbandry systems in Greece

Giardia duodenalis and Cryptosporidium spp. are gastro-intestinal protozoa known to infect small ruminants. Both protozoa are also considered as a potential public health concern. The objective of this study was to determine their prevalence in lambs and goat kids kept under common Mediterranean dairy husbandry systems and to identify the species and genotypes infecting these small ruminants. In total, 684 faecal samples (429 from lambs and 255 from goat kids) were collected on 21 farms in Greece and examined using a quantitative immunofluorescence assay. G. duodenalis was detected in 37.3% of the lambs and 40.4% of the goat kids. On all but one of the farms G. duodenalis was detected. Most samples were typed as a mono-infection with G. duodenalis assemblage E, both on the β-giardin gene and the triose phosphate isomerase gene. Only 10% of samples were typed as mixed assemblage A and E infections. The prevalence of Cryptosporidium spp. was 5.1% in lambs and 7.1% in goat kids. In total, 8 out of the 14 farms with a sheep flock and 7 out of the 14 farms with a goat flock were positive. Cryptosporidium parvum (subtype IId), C. ubiquitum and C. xiaoi were identified, the latter especially in goat kids. In conclusion, the results of the present study illustrate that G. duodenalis and Cryptosporidium spp. occur frequently on both sheep and goats farms. The prevalence of zoonotic genotypes or species was low, indicating a limited but existing risk for zoonotic infections.