The effect of feeding sulla (Hedysarum coronarium) or lucerne (Medicago sativa) on lamb parasite burdens and development of immunity to gastrointestinal nematodes

Review: Herbivory and the power of phytochemical diversity on animal health

Plant secondary compounds (PSCs) were thought to be waste products of plant metabolism when first identified in the mid-1800 s. Since then, many different roles have been recognized for these chemicals. With regard to their function as defense, PSCs can negatively impact different cellular and metabolic processes in the herbivore, causing illness and reductions in feed intake. This penalty on fitness also applies to other trophic levels, like the microorganisms and parasites that infect herbivores and thus, PSCs at certain doses may function as medicines. In turn, herbivores evolved learning mechanisms to cope with the constant variability in their environment and physiological needs. Under this context, foraging can be viewed as the quest for substances in the external environment that provide homeostatic utility to the animal. For instance, herbivores increase preference for PSC-containing feeds that negatively impact infectious agents (i.e., therapeutic self-medication). Given that some classes of PSCs like polyphenols present antioxidant, antiinflammatory, immunomodulatory and prebiotic properties, chronic and sustained consumption of these chemicals results in robust animals that are tolerant to disease (i.e., prophylactic self-medication). Foraging plasticity in terms of the quality and quantity of nutrients ingested in the absence and during sickness may also influence immunocompetence, resistance and resilience to infection, and thus can be interpreted as another form of medication. Finally, self-medicative behaviors can be transmitted through social learning. We suggest that foraging studies will benefit from exploring self-medicative behaviors in chemically diverse plant communities, in particular when considering the vast diversity of PSC structures (more than 200 000) observed in nature. We then lay out a framework for enhancing the medicinal effects of PSCs on grazing herbivores. We propose landscape interventions through the establishment of resource patches or "islands" with a diversity of PSC-containing forages (e.g., legumes, herbs, shrubs) in monotonous rangelands or pasturelands, viewed as a "sea" of low-diversity vegetation devoid of functional biochemicals. Strategies aimed at enhancing the diversity of plant communities lead to heterogeneity in chemical, structural and functional landscape traits that offer options to foragers, and thus allow for balanced diets that maintain and restore health. Beyond animal health, such heterogeneity promotes a broad array of ecosystem services that significantly improve landscape resilience to environmental disturbances.

Sulla (Hedysarum coronarium L.) Response to Drought Stress during Early Vegetative Stage

Sulla (Hedysarum coronarium L.) is a Mediterranean biannual anthelmintic forage. Due to its high productivity, nutraceutical value, and suitability for harsh environments, interest in this crop is growing. Under the current scenario of climate change and water scarcity, it is important to evaluate crop drought tolerance, especially for newly bred materials. Drought stress and well-watered conditions (50 vs. 80% of the field capacity) were applied in a pot experiment to compare responses of the widespread commercial variety Bellante with those of a recently released variety named 'Centauro', currently registered in the Italian national register of plant varieties but not yet available on the market. Compared to the well-watered treatment, drought-stressed plants showed lower values of fresh biomass (-69%), number of leaves (-68%), and root length (-49%). The Centauro cv. showed a different architecture to Bellante with more shoots (+43% P < 0.05) and a trend for more leaves (+25% P = 0.08). These traits are possibly related to its superior palatability. Centauro also developed a higher root length (+70%, P < 0.05) across irrigation levels. Drought stress affected condensed tannin (CT) content. A significant genotype × environment interaction was found with Centauro displaying more (+50%) and less (-35%) CT than Bellante under drought stress and well-watered conditions, respectively. The higher constitutive root length density of Centauro may be exploited in breeding programs aimed at improving the root sink, given the role of this trait in resource acquisition capacity and root-derived ecosystem services.

Effect of commercial tannins on parasitic infection and immunity of lambs naturally infected with Haemonchus contortus

This study aimed to evaluate the effects of different doses of quebracho extract tannins (Schinopsis lorenzii) (EQ) included in the basal diet (DB) on the count of eggs per gram of feces (EPG), count of parasites in the abomasum, hematological, and immunological parameters in lambs naturally infected with Haemonchus contortus. Forty-eight lambs were evaluated for 42 days and divided into four groups (n = 12): CONT- lambs that received DB without EQ supplementation; G1%- DB with EQ at 1% of dry matter intake (DMI) level; G3%- DB with EQ at the 3% of DMI level; G6%- DB with EQ at the 6% DMI level. For EPG counts, feces were collected weekly. For counting abomasal parasites, at the end of the experiment (D42) half of the lambs in each group were slaughtered. For hematological and immunological analysis, venous blood samples were collected at D0, D21, and D42 to perform the erythrocyte count, mean cell volume (MCV), hematocrit, differential leukocyte count, total plasma protein dosage, and serum IgA class anti-H. contortus using an indirect enzyme immunoassay (ELISA). In the EPG count, there was no significant difference (p > 0.05) between the groups compared with the control. Analysis of the abomasal parasite count showed Haemonchus contortus in its entirety; however, there was no significant difference (p > 0.05) in the number of males, females, and total parasites. No differences (p > 0.05) were observed in erythrocyte count, MCV, hematocrit, and total plasma protein. The average total leukocyte, monocyte, eosinophil, and basophil counts showed no difference (p > 0.05). However, the averages of segmented neutrophils in the G1% and G3% groups presented a reduction in the percentage of cells (p < 0.05) between D21 and D42. Regarding the lymphocyte count, a difference was observed in the CONT and G3% groups at D21 and D42 (p < 0.05), when compared to D0. The analyses of the average absorbance of anti-Haemonchus contortus serum IgA showed no difference (p > 0.05), when the groups were analyzed over time or when compared between them. It can be concluded that the inclusion of different doses of tannins from EQ did not alter the parasitological, hematological, and immunological parameters of lambs infected with H. contortus.

Antiparasitic Tannin-Rich Plants from the South of Europe for Grazing Livestock: A Review

Internal parasites are one of the main causes of health threats in livestock production, especially in extensive livestock farming. Despite the environmental toxic effects (loss of dung beetles, biodiversity, and other issues) and resistance phenomenon derived from their prolonged use, anti-parasitic chemical pharmaceuticals are frequently used, even in organic farming. Such a situation within the context of climate change requires urgent exploration of alternative compounds to solve these problems and apparent conflicts between organic farming objectives regarding the environment, public health, and animal health. This review is focused on some plants (Artemisia spp., Cichorium intybus L., Ericaceae family, Hedysarum coronarium L., Lotus spp., Onobrychis viciifolia Scop.) that are well known for their antiparasitic effect, are voluntarily grazed and ingested, and can be spontaneously found or cultivated in southern Europe and other regions with a Mediterranean climate. The differences found between effectiveness, parasite species affected, in vitro/in vivo experiments, and active compounds are explored. A total of 87 papers where antiparasitic activity of those plants have been studied are included in this review; 75% studied the effect on ruminant parasites, where gastrointestinal nematodes were the parasite group most studied (70%), and these included natural (31%) and experimental (37%) infections.

Nematicidal Potential of Sulla (Hedysarum coronarium L.) against the Root-Knot Nematode Meloidogyne incognita

The content of nematicidal metabolites such as saponins, flavonoids and tannins in sulla (Hedysarum coronarium L.) suggests its potential nematicidal activity. In this study, the biocidal activity of 62.5–1000 μg mL⁻¹ concentrations of flavonoid and tannin fractions from sulla was assessed in in vitro assays on the infective juveniles (J2) of the root-knot nematode (RKN) Meloidogyne incognita, while the suppressive effects of soil amendments with 10–40 g kg⁻¹ soil rates of sulla biomass were investigated on potted tomato infested by M. incognita. The content of total nitrogen, carbon, flavonoids, tannins and saponins of sulla experimental material was also determined. After a 96-h exposure, more than 80% of the M. incognita J2 were killed even by a 125 µg mL⁻¹ concentration of the flavonoid extract, while mortality peaked at 89% only at the 1000 µg mL⁻¹ concentration of the tannin solution. Soil incorporation with sulla biomass significantly reduced the M. incognita densities both on tomato roots and in the soil, compared to either the non-treated control and chemical treatment with Fluopyram. The data confirmed the nematicidal potential of sulla, mainly due to its content of flavonoids and tannins, suggesting its suitability as green manure or a soil amendment for sustainable RKN management.

Grassland-based ruminant farming systems in China: Potential, challenges and a way forward

With an increasing demand for high-quality, eco-friendly food products and growing concerns over ecological conservation, the development of ecology-based alternatives for ruminant production in China is urgently needed. This review discusses the capabilities for integrating grassland grazing into existing livestock farming systems to meet the contemporary human needs for high-quality foods and ecologically stable environments. Additionally, this review provides a critical analysis of the challenges and future directions associated with grassland-based ruminant farming systems. Integrating nutritional manipulation with grazing manipulation is critical for improving the productivity of grassland-based ecosystems and natural ecological functions. Biodiversity is the primary determinant of grassland ecosystem functions, while the composition and function of rumen microbiomes determine ruminant production performance. Future studies should focus on the following aspects: 1) how livestock grazing regulates grassland biodiversity and the mechanisms of grassland biodiversity maintenance, offering an important scientific basis for guiding grazing manipulation practices, including grazing intensity, livestock types, and grazing management practices; to 2) characterize the microbial ecology within the rumen of grazing ruminants to offer clarified instruction for the nutritional manipulation of grazing ruminants. Our recommendation includes creating a transdisciplinary system that integrates ecology, animal nutrition, and animal behavior to develop grassland-based ruminant farming systems sustainably, thereby achieving high-quality animal production and environmentally sustainable goals.

Acaricidal activity of the hexanic and hydroethanolic extracts of three medicinal plants against southern cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)

The southern cattle tick Rhipicephalus microplus is a major problem for the cattle industry in tropical and subtropical areas worldwide. Chemical products are commonly applied to control it; however, their indiscriminate use has resulted in the appearance of resistant lineages. In the last decades, plants have been used as an alternative to conventional acaricidal drugs, as several plant compounds repel activity, decrease the reproductive potential and reduce the survival rate of ticks. For this reason, the in vitro efficacy of hexanic and hydroalcoholic extracts of Randia aculeata, Moringa oleifera and Carica papaya were evaluated against the larvae and engorged females of R. microplus. Larval packet tests and adult immersion tests were performed with seven concentrations of each of the extracts. The extracts obtained with hydroethanolic solution (polar solvent) exhibited a higher acaricidal activity than extracts prepared with n-hexane (non-polar solvent). Hydroethanolic extracts of R. aculeata seed and shell showed the highest larvicidal activity against R. microplus (100 and 91% mortality, respectively) at a concentration of 100 mg/mL. Randia aculeata (seed and shell), M. oleifera and C. papaya treatments at the same concentration (100 mg/mL) also resulted in adult mortality of 85, 75, 66 and 55%, respectively. The adult immersion test showed that hydroethanolic extracts derived from R. aculeata seed significantly reduced the index of egg laying and increased the percentage inhibition of oviposition of female ticks at a concentration of 100 mg/mL. These results indicate that the tested extracts exhibit acaricidal activity and could be considered as potential agents for the development of alternative natural acaricides against R. microplus.

Chemical Identification of Specialized Metabolites from Sulla (Hedysarum coronarium L.) Collected in Southern Italy

Sulla (Hedysarum coronarium L.) is a biennal forage legume originated from the Mediterranean basin and used for animal feeding due to its high forage quality and palatability. Several species of Hedysarum have been considered for their nutritional, pharmaceutical, and biological properties, and different applications have been reported, both for human consumption and animal nutrition. Although a systematic investigation of the chemical constituents of Hedysarum spp. has been performed in order to provide chemotaxonomic evidences for the genus and to support the pharmacological application of several species within the genus, few data are available on the chemical constituents of H. coronarium, and only the content of condensed tannins and flavonoids in leaves has been previously reported. In the present paper, results from a detailed chemical analysis of the extracts from the leaves and flowers of H. coronarium grown wild in southern Italy are presented. Identification of the main specialized metabolites within the chemical classes of flavonoids, proanthocyanidins and saponins, is described, including considerations on their content in the two plant organs. Information acquired from this study expands the knowledge on H. coronarium as a source of valuable phytochemicals for different applications in human and animal health and nutrition.

Advances in the discovery and development of anthelmintics by harnessing natural product scaffolds

Widespread resistance to currently-used anthelmintics represents a major obstacle to controlling parasitic nematodes of livestock animals. Given the reliance on anthelmintics in many control regimens, there is a need for the continued discovery and development of new nematocides. Enabling such a focus are: (i) the major chemical diversity of natural products; (ii) the availability of curated, drug-like extract-, fraction- and/or compound-libraries from natural sources; (iii) the utility and practicality of well-established whole-worm bioassays for Haemonchus contortus-an important parasitic nematodes of livestock-to screen natural product libraries; and (iv) the availability of advanced chromatographic (HPLC), spectroscopic (NMR) and spectrometric (MS) techniques for bioassay-guided fractionation and structural elucidation. This context provides a sound basis for the identification and characterisation of anthelmintic candidates from natural sources. This chapter provides a background on the importance and impact of helminth infections/diseases, parasite control and aspects of drug discovery, and reviews recent work focused on (i) screening well-defined compound libraries to establish the methods needed for large-scale screening of natural extract libraries; (ii) discovering plant and marine extracts with nematocidal or nematostatic activity, and purifying bioactive compounds and assessing their potential for further development; and (iii) synthesising analogues of selected purified natural compounds for the identification of possible 'lead' candidates. The chapter describes some lessons learned from this work and proposes future areas of focus for drug discovery. Collectively, the findings from this recent work show potential for selected natural product scaffolds as candidates for future development. Developing such candidates via future chemical optimisation, efficacy and safety evaluations, broad spectrum activity assessments, and target identification represents an exciting prospect and, if successful, could pave the way to subsequent pre-clinical and clinical evaluations.

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.

The Potential Effect of Dietary Tannins on Enteric Methane Emission and Ruminant Production, as an Alternative to Antibiotic Feed Additives – A Review

Antibiotic growth promoters in livestock nutrition cause microbial resistance which produces threats to human health. Therefore, tannins have been considered as natural alternative antibiotic feed additives which possess various biological properties including antimicrobial, anti-inflammatory, antioxidant and immunomodulatory. Additionally, these plants also have antiparasitic and anti-bloat characteristics which contribute to inhibit the enteric methane emission in order to improve nutrient digestibility, milk and meat quality, fatty acids composition and ruminant production. Antibiotic growth promoters have been practiced in animals feeding to increase feed intake, growth rate, weight gain as well as reduce metabolic disorders and energy losses in the rumen. In 2006, the European Union banned the usage of antibiotic growth promoters in the feeding of livestock. This antibiotic resistance issue has increased demand to explore the natural feed additives that might be useful for animal production system. Consequently, natural forages have been categorized as potential feed additives in animal production since it improves nutritive value, protein digestibility, increase amino acid absorption and growth rate. But, some plant materials are usually rich in tannins known as anti-nutritional factors. Therefore, the application of tannin-rich plants in ruminant nutrition needs great precaution due to its possible injurious effects (dose dependent) on animal health such as metabolic disorders. Hence, there is need to give attention to the usage of tannins in ruminant nutrition as an alternative to antibiotics feed additives to investigate its effects on enteric methane emissions and ruminants production. In addition, safety and risk associated with tannins feeding have also been briefly discussed.

A polyphenol-enriched diet and Ascaris suum infection modulate mucosal immune responses and gut microbiota composition in pigs

Polyphenols are a class of bioactive plant secondary metabolites that are thought to have beneficial effects on gut health, such as modulation of mucosal immune and inflammatory responses and regulation of parasite burdens. Here, we examined the interactions between a polyphenol-rich diet supplement and infection with the enteric nematode Ascaris suum in pigs. Pigs were fed either a basal diet or the same diet supplemented with grape pomace (GP), an industrial by-product rich in polyphenols such as oligomeric proanthocyanidins. Half of the animals in each group were then inoculated with A. suum for 14 days to assess parasite establishment, acquisition of local and systemic immune responses and effects on the gut microbiome. Despite in vitro anthelmintic activity of GP-extracts, numbers of parasite larvae in the intestine were not altered by GP-supplementation. However, the bioactive diet significantly increased numbers of eosinophils induced by A. suum infection in the duodenum, jejunum and ileum, and modulated gene expression in the jejunal mucosa of infected pigs. Both GP-supplementation and A. suum infection induced significant and apparently similar changes in the composition of the prokaryotic gut microbiota, and both also decreased concentrations of isobutyric and isovaleric acid (branched-chain short chain fatty acids) in the colon. Our results demonstrate that while a polyphenol-enriched diet in pigs may not directly influence A. suum establishment, it significantly modulates the subsequent host response to helminth infection. Our results suggest an influence of diet on immune function which may potentially be exploited to enhance immunity to helminths.

The Occurrence, Biosynthesis, and Molecular Structure of Proanthocyanidins and Their Effects on Legume Forage Protein Precipitation, Digestion and Absorption in the Ruminant Digestive Tract

Forages grown in temperate regions, such as alfalfa (Medicago sativa L.) and white clover (Trefolium repens L.), typically have a high nutritional value when fed to ruminants. Their high protein content and degradation rate result, however, in poor utilization of protein from the forage resulting in excessive excretion of nitrogen into the environment by the animal. Proanthocyanindins (also known as condensed tannins) found in some forage legumes such as birdsfoot trefoil (Lotus corniculatus L.), bind to dietary protein and can improve protein utilization in the animal. This review will focus on (1) the occurrence of proanthocyanidins; (2) biosynthesis and structure of proanthocyanidins; (3) effects of proanthocyanidins on protein metabolism; (4) protein precipitating capacity of proanthocyanidins and their effects on true intestinal protein adsorption by ruminants; and (5) effect on animal health, animal performance and environmental emissions.

The use of <i>Lespedeza cuneata</i> for natural control of gastrointestinal nematodes in Merino sheep

Lespedeza cuneata (poorman’s lucerne; sericea lespedeza), a tannin-rich perennial legume, was offered as hay to dry Merino ewes in a confined feeding experiment to evaluate the effect on the level of gastrointestinal parasite infection in sheep. Medicago sativa (a low tannin containing perennial legume) was used as the control treatment. Parameters faecal egg count (FEC), FAMACHA^© scores and rectal temperatures were used. FECs were substantially lower (p = 0.05) in the Lespedeza group after 35 days, together with a trend of higher rectal temperatures, compared with the Medicago group. Although non-significant (p > 0.05), the higher rectal temperatures suggested a lower level of anaemia in the sheep on the Lespedeza ration and, therefore, a lower parasite-worm burden. However, FAMACHA^© scores showed no significant (p > 0.05) differences between treatments despite the differences in FEC that were recorded, indicating that host homeostasis was possibly mediated by improved nutrition as a result of the high protein content of both experimental diets.

Effect of tanniferous leaf meal based multi-nutrient blocks on feed intake, hematological profile, immune response, and body weight changes in Haemonchus contortus infected goats

Aim:

The aim was to assess the effect of multi nutrient block (MNB) supplementation with and without tanniferous leaf meal mixture on feed intake, hematological profile, immune response, and body weight changes of goats that were experimentally infected with Haemonchus contortus.

Materials and Methods:

Total 12 adult male goats of similar age and body weight (26.49±0.87) were allocated in 3 groups in completely randomized design. MNB supplemented in first two groups i.e. in T₁ (no infection) and T₂ (H. contortus infection @ 1500 L₃/goat) group, while, MNB-condensed tannin (CT) supplemented in T₃ (H. contortus infection @ 1500 L₃/goat + CT source). All goats were fed concentrate mixture @ 100 g/day/goat, ad lib wheat straw and MNB or MNB-CT to meet their requirement for maintenance. Body weights were recorded and blood and fecal samples were collected at 0 day and thereafter at 15 days intervals for a period of 75 days for the assessment of body weight changes, hematological profile and H. contortus loads. Both humoral and cell-mediated immune (CMI) response were assessed at the end of feeding trial.

Results:

Mean hemoglobin and packed cell volume (PCV) levels were found to be highest (p<0.001, p<0.05) in T₁ group followed by T₃ group and lowest values were observed in T₂ group. However, The PCV values between T₁ and T₃ groups were found to be statistically non-significant (p<0.05). The humoral and CMI response were significantly (p<0.036) higher in T₃ group as compared to T₂ group. MNB-CT supplementation significantly (p<0.001) reduced fecal egg counts in T₃ group as compared to MNB supplemented T₂ group.

Conclusion:

Supplementation of MNB-CT could be used as an alternative sustainable method to control H. contortus and maintained health status and performance of goats in face of parasitic challenge.

In vitroassessment of the anthelmintic activity ofHedysarum carnosumDesf. at different phenological stages and from six locations in Tunisia

Gastrointestinal nematodes are compromising productivity of grazing sheep and goats. Therefore, scientists have been looking for cost-effective alternative options. Forage legumes (Fabacea Family) contain tannins that could improve livestock performance and their health as well. The present study aimed to (i) determine thein vitroanthelmintic (AH) activity of 19 acetonic extracts ofHedysarum carnosumDesf onHaemonchus contortusby a larval exsheathment assay (LEA); (ii) test the anthelmintic activity of condensed tannins using a deactivating reagent, polyvinylpolypyrrolidone (PVPP); (iii) study the effect of location and the phenological stage on the percentage of exsheathment. The LEA was used at different concentrations (150, 300, 600, 1200µg mL−1of acetonic extract/mL of purified buffer solution (PBS)). The larval exsheathment is concentration, location, phenological stage dependent. All extracts, caused a delay of the percentage of exsheathment over 50% so the AH activity ofH. carnosumwas confirmed. After addition of PVPP, the % exsheathment was similar to the 150µg mL−1concentration. The biplot showed that Loc1(S), Loc4(B), Loc 5(PF), Loc 6(BM) and Loc 6(PF) were isolated from other plant extract sample. Ourin vitrostudy showed thatH. carnosumseems to be a promising alternative to AH drugs.

Dried, ground banana plant leaves (Musa spp.) for the control of Haemonchus contortus and Trichostrongylus colubriformis infections in sheep

To evaluate the anthelmintic effect of Musa spp. leaves, 12 animals were artificially infected with Haemonchus contortus, and another 12 animals were infected with Trichostrongylus colubriformis. Then, both treatment groups were offered 400 g of dried ground banana plant leaves, and the control animals were offered only 1000 g of coast cross hay. During the trials, the animals received weekly physical examinations. The methods used to evaluate the efficiency of this treatment were packed cell volume, total plasma protein and faecal egg counts, and egg hatchability tests were performed on days -2, +3, +6, +9, +13 and +15. Coproculture tests were performed on day -2 to confirm monospecific infections. In the FEC and EHT, a statistically significant difference (0.04, 0.005; p < 0.05) was noted for T. colubriformis. There were no statistically significant differences (p > 0.05) for Haemochus contortus group in all tests. Our results confirmed previous findings suggesting that dried ground banana plant leaves possess anthelmintic activity.

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).

Effects of supplementation with dietary green tea polyphenols on parasite resistance and acute phase protein response to Haemonchus contortus infection in lambs

The objective of this study was to determine the effects of supplementation with dietary green tea polyphenols (GTPs) on parasite resistance and acute phase protein (APP) response to Haemonchus contortus infection in lambs. Thirty male Ujumqin lambs were randomly assigned to five treatment groups for an 8-week feeding period. Treatments included: (1) uninfected as control, (2) infected but not given GTP (INFGTP0) and (3)-(5) infected and fed 2, 4, or 6g GTP/kg feed (dry matter basis; INFGTP2, INFGTP4, and INFGTP6, respectively). Fecal and blood samples were collected to determine fecal egg count (FEC), packed cell volume (PCV), and APP concentrations. Live weight was measured once every 2 weeks. At the end of the feeding period, lambs were slaughtered to determine the adult H. contortus burden. The results demonstrated interaction effects between treatment and sampling time on the average daily gain (ADG; P=0.0005), FEC (P<0.0001), PCV (P=0.0005), and concentrations of serum amyloid A (SAA), haptoglobin (Hp), lipopolysaccharide binding protein (LBP), and α1-acid glycoprotein (α1AGP) (P<0.0001). From days 0 to 56, the ADG values for all infected lambs were lower than that of uninfected lambs, but the ADG values for all GTP-fed lambs were higher than that of INFGTP0 lambs, especially from days 28 to 42. The FECs of all GTP-fed lambs were higher than those of uninfected lambs but lower than that of INFGTP0 lambs. The PCVs of all infected lambs were lower than those of uninfected lambs, but PCV increased with increasing amounts of GTP supplementation. Furthermore, supplementation with different concentrations of GTP significantly reduced the numbers of adult H. contortus, including both males and females (P<0.0001), and the H. contortus burden in INFGTP6 lambs was reduced to uninfected levels. Overall, the SAA, Hp, LBP, and α1AGP concentrations of all infected lambs were higher than those of uninfected lambs from days 0 to 56. Two peaks in expression were observed from days 0 to 3 and at day 28, and APP concentrations of all GTP-fed lambs were lower than those of INFGTP0 lambs, except for SAA in INFGTP6 lambs. In conclusion, quantitative measurements of APP responses to H. contortus infection provide valuable diagnostic information for monitoring infection progression and treatment responses in lambs. An appropriate dose of dietary GTP supplementation can increase host resistance by reducing H. contortus burden and weight loss and suppressing blood APP expression.

Effect of condensed tannins supplementation through leaf meal mixture on voluntary feed intake, immune response and worm burden in Haemonchus contortus infected sheep

The study was carried out to assess the effect of condensed tannins (CT) supplementation through leaf meal mixture (LMM) on feed intake, humoral [Immunoglobulin G (IgG)], cell mediated immune response (CMI) and faecal egg counts in Haemonchus contortus infected sheep. Eighteen sheep were randomly divided into three groups (negative control-NC, infected control-C and Infected treatment-T) of six animals in each group in a completely randomized block design for a period of 90 days. Twelve H. contortus infected adult sheep were allocated into two equal groups C and T, supplemented with 0 and 1.5 % of CT, respectively. Six non-infected sheep of similar age and body weight of NC group were included in this study to compare their immune response with H. contortus C and CT supplemented T groups. Intake of dry matter and organic matter (g day(-1) and % live weight) was statistically similar (P < 0.05) among the three groups. The anti-Haemonchus IgG and CMI response was higher in T group as compared to C group. The mean faecal egg counts was significantly (P < 0.001) higher in C group as compared to T group. It may be concluded that dietary supplementation of CT (1.5 %) through LMM improved humoral and CMI immune response and decreased worm load in H. contortus infected sheep.

Effects of tannic acid on Haemonchus contortus larvae viability and immune responses of sheep white blood cells in vitro

Direct inhibitory effects of tannic acid on Haemonchus contortus viability were studied in vitro using the larval migration inhibition (LMI) assay. Sheep white blood cells (WBC) were preincubated with 5 and 50 lg/mL tannic acid or not followed by whole H. contortus antigen (WHA). Cells were harvested at 24 h post-incubation to test host immune responses. Concentrations of 50, 100, 500, 1000, 3000 and 5000 lg/mL tannic acid inhibited larvae migration by 19.8, 42.4, 46.3, 92.0, 93.7 and 100%, respectively, within 96 h post-incubation (P < 0.001). The relative mRNA levels of interferon (IFN)-c, interleukin (IL)-2, IL-4 and IL-10 were increased by WHA stimulation without tannic acid. However, the increased effects on IFN-c and IL-2 were inhibited by tannic acid preincubation (P < 0.001), while the increases in IL-4 and IL-10 were greatly enhanced by tannic acid preincubation (P < 0.001). Changes in protein levels of all cytokines essentially paralleled the changes in their corresponding mRNA levels. In conclusion, tannic acid is directly harmful to larvae in a dose- and time-dependent manner and modulates immune responses of sheep WBC stimulated by H. contortus antigen by inhibiting Th1 cytokines and increasing Th2 cytokine expression in vitro.

Influence of fresh forage-based diets and αs₁-casein (CSN1S1) genotype on nutrient intake and productive, metabolic, and hormonal responses in milking goats

Polymorphism at the αS1-casein locus (CSN1S1) in goats influences several milk production traits. Milk from goats carrying strong alleles, which are associated with high αS1-casein (αS1-CN) synthesis, has higher fat and casein contents, longer coagulation time and higher curd firmness than milk from goats with weak alleles linked to low αS1-CN content. Nutrition also affects these milk properties; therefore, it is important to better understand the interaction between dietary characteristics and the CSN1S1 genotype in goats. This study aimed to investigate the effect of fresh forage based diet or energy supplement on feeding behavior, milk production, and metabolic and hormonal parameters of Girgentana goats with different genotypes at CSN1S1 loci. From a group of goats genotyped by PCR at the DNA level, 12 were selected because they had the same genotype for αS2-CN, β-CN, and κ-CN but a different genotype for αS1-CN: 6 were homozygous for strong alleles at the CSN1S1 loci (AA) and 6 were heterozygous for a weak allele (AF). Goats of each genotype were allocated to 3 subgroups and fed 3 diets ad libitum in a 3×3 Latin square design. The diets were sulla (Hedysarum coronarium L.) fresh forage, sulla fresh forage plus 800 g/d of barley meal (SFB), and mixed hay plus 800 g/d of barley meal (MHB). Diet had a stronger effect than CSN1S1 genotype. The SFB diet led to the highest energy intake, dry matter (DM) digestibility, and milk yield. The fresh forage diets (SFF and SFB) increased DM and crude protein (CP) intake, CP digestibility, and milk CN compared with the MHB diet. The diets supplemented with energy (SFB, MHB) reduced milk fat and urea, improved CP utilization for casein synthesis, and limited body fat mobilization, in accordance with a lower level of nonesterified fatty acids and higher levels of glucose and IGF-1. With regard to CSN1S1 genotype, AA goats showed higher CP digestibility and lower free thyroxine hormone and cholesterol levels than AF goats. Significant diet × genotype interactions indicated how AA goats, compared with AF goats, showed higher DM digestibility and milk yield when fed the SFB diet, which had more energy. A reduction in free triiodothyronine hormone occurred in AF goats fed the MHB diet, whereas no differences were observed in AA goats. These results demonstrate how goats with a higher capacity for αS1-CN synthesis exhibit more efficient energy and protein utilization, evident at the digestive level, and better productive responses to high-nutrition diets.

Influence of saponins and tannins on intake and nutrient digestion of alkaloid-containing foods

BACKGROUND

We hypothesized that eating a food containing saponins (SAP), or tannins (TAN) prior to foods containing the alkaloids gramine (GRA) or 5-methoxy-N,N-dimethyltryptamine (TRP) would provide benefits not possible when the alkaloid-containing foods were eaten alone.

METHODS

In Trial 1, four groups of five lambs were first offered food with SAP for 30 min followed by food with either GRA or TRP for 3.5 h in a 2 × 2 factorial arrangement of a completely randomized design that included alkaloid (GRA or TRP) with or without SAP. In Trial 2 TAN replaced SAP. All foods were isocaloric (3.3 Mcal kg⁻¹) and isonitrogenous (14% crude protein). Foods, fecal and urine samples were collected and analyzed for dry matter intake and apparent digestibility of dry matter, energy (in megajoules, MJ), nitrogen (N), and neutral detergent fiber.

RESULTS

Supplemental SAP did not affect digestibility of the parameters tested (P > 0.10). Supplemental TAN increased digestibility of N (g kg⁻¹, P = 0.04), N retained (g day⁻¹, P = 0.07), N digested (g day⁻¹, P = 0.06), and N retained/N consumed (g kg⁻¹, P = 0.07). However, digestibilities of dry matter (g kg⁻¹, P = 0.0026), energy (MJ 1000 MJ⁻¹, P = 0.003), neutral detergent fiber (g kg⁻¹, P = 0.008), and digested N retained (g kg⁻¹, P = 0.07) were lower for lambs fed TAN than for unsupplemented animals.

CONCLUSIONS

Tannin supplementation can improve retention of nitrogen in animals fed alkaloid-containing grasses such as reed canarygrass and tall fescue. Combinations of forages with complementary primary and secondary compounds enable animals to maintain intake and improve nutrient utilization.

The potential of Elephantorrhiza elephantina as an anthelminthic in goats

Elephantorrhiza elephantina Bruch. Skeels. is used by farmers in the Eastern Cape Province to control helminths in goats. An in vitro study revealed efficacy of its fractions against adult Haemonchus contortus. This study was conducted to validate efficacy of fractions in vivo, on gastrointestinal nematodes in naturally infected goats. A total of 36 goats (18 males and 18 females) between ages of 8 and 12 months were used; these were randomly assigned to six treatments (A-F). For treatments A and B, goats received Prodose orange® (Albendazole 1.92 % m/v, closantel 3.94 % mv) at 2 ml/10 kg and distilled water at 0.5 ml/kg per os, respectively, whereas those under treatments C to E received aqueous fractions of E. elephantina at concentrations of 12. 5, 25, 50 and 75 mg/ml, dosed at 2 ml/10 kg. On days 1, 28 and 56, faecal samples were collected for faecal egg counts (FEC) and larval count, blood samples taken for packed cell volume (PCV) and body weights recorded to assess weight changes. The aqueous fraction caused highest the total faecal egg count reductions (TFECR) % of 81.7 %, 96.8 % and 98.6 % at doses of 25, 50 and 75 mg/kg, respectively, on day 56. This was comparable to the commercial drug Prodose orange®, which caused TFECR% of 94.9 % at the same time. The fraction also caused reduction of Haemonchus contortus and strongyloides larvae at all dose levels, but these were not significantly different (P > 0.05) to the negative control. There was an increase in body weights of animals at dose concentrations of 25, 50 and 75 mg/kg. Animals receiving the fraction had weight increases of between 3 and 4 kg by end of experiment (over 56 days), but those drenched with Prodose orange ® gained by less than 2 kg. The fraction also increased PCV levels at all doses on days 28 and 56 and this was comparable to the group on commercial drug. The reductions of FEC and worm larvae, as well as increase in PCVs are indicative that E. elephantina posses some antihelmintic properties against gastrointestinal parasites in goats. With a minimum dose concentration of 25 mg/ml being effective, this means that farmers can use little material. Increase in weight gain revealed in this study may indicate that the plant may have some nutritional value; further study is therefore called for to validate the plant for its nutritive value.

Experiences with integrated concepts for the control of Haemonchus contortus in sheep and goats in the United States

The generally warm, moist environmental conditions in the southern United States (U.S.) are ideal for survival and growth of the egg and larval stages of Haemonchus contortus and other gastrointestinal nematodes (GIN) of sheep and goats. Consequently, infection with GIN is the greatest threat to economic small ruminant production in this region. With anthelmintic resistance now reaching epidemic proportions in small ruminants in the U.S., non-chemical control alternatives are critically needed. The Southern Consortium for Small Ruminant Parasite Control (SCSRPC) was formed in response to this crisis and over the last decade has successfully validated the use of several novel control technologies, including FAMACHA(©) for the implementation of targeted selective treatments (TST), copper oxide wire particles (COWP), nematode-trapping fungi, and grazing or feeding hay of the high-tannin perennial legume sericea lespedeza [Lespedeza cuneata (Dum.-Cours. G. Don)]. Producer attitudes toward GIN control in the U.S. have been shifting away from exclusive dependence upon anthelmintics toward more sustainable, integrated systems of parasite control. Some novel control technologies have been readily adopted by producers in combination with appropriate diagnostic tools, such as FAMACHA(©). Others techniques are still being developed, and will be available for producer use as they are validated. Although new drugs will likely be available to U.S. goat and sheep producers in the future, these will also be subject to development of anthelmintic resistance. Therefore, the adoption and implementation of sustainable GIN control principles will remain important. With emerging markets for grass-fed or organic livestock, there will continue to be a critical need for research and outreach on development and on-farm application of integrated GIN control systems for small ruminants in the U.S. for the foreseeable future.

Condensed tannins and flavonoids from the forage legume sulla (Hedysarum coronarium)

The condensed tannin concentrations and composition and the characterization of the phenolic constituents in the leaves of the forage legume sulla (Hedysarum coronarium), a biennial forage legume found in temperate agricultural regions, were studied. The colorimetric butanol-HCl assay was used for the quantitation of the seasonal condensed tannin concentrations in the leaves of sulla. Fractionation of extracts on Sephadex LH-20 using step elution with aqueous methanol, followed with aqueous acetone or gradient elution with water, aqueous methanol, and aqueous acetone, gave condensed tannin and flavonoid fractions. The chemical characteristics of the purified condensed tannin fractions were studied by acid-catalyzed degradation with benzyl mercaptan and electrospray ionization mass spectrometry (ESI-MS). Thiolysis revealed that epigallocatechin was the major extender unit (15-75%) while gallocatechin was the major terminal unit (50-66%), thus indicating the extractable sulla condensed tannin fraction as the prodelphinidin type. Condensed tannin oligomers to polymers obtained from Sephadex LH-20 gradient fractions ranged between 2.9 and 46 mDP. The homo- and heterogeneous oligomer ions in condensed tannin gradient fractions detected by ESI-MS ranged from 2 to 10 DP and are consistent with the values obtained by thiolysis (2.9-6.9 DP). Lower molecular weight phenolics, including flavonoids and phenolic acids, were characterized by liquid chromatography atmospheric pressure chemical ionization mass spectrometry (LC-APCI/MS) and ESI/MS/MS on a linear ion trap. The flavonoids extracted with aqueous acetone and methanol from sulla leaves and identified included kaempferol, rutin, quercetin-7-O-α-L-rhamnosyl-3-O-glucosylrhamnoside, quercetin-3-O-α-L-rhamnosyl-7-O-glucoside, kaempferol-3-O-β-D-glucoside-dirhamnoside, genistein-7-O-β-D-glucosyl-6″-O-malonate, formononetin-7-O-β-D-glucoside-6″-O-malonate, and afrormosin and the phenolic acid chlorogenic acid.

Anthelmintic screening of fractions of Elephantorrhiza elephantina root extract against Haemonchus contortus

In the previous work conducted, it was found that the root extract of Elephantorrhiza elephantina (Bruch.) Skeels. exhibited good anthelmintic efficacy against eggs and larvae of Haemonchus contortus. This study was therefore undertaken to screen fractions of the extracts of E. elephantina for their anthelmintic activity against adult H. contortus using a bioactivity-guided assay. The adult worm bioassay was conducted using aqueous, hexane and ethyl acetate fractions of the plant extracts at concentrations of 0.312, 0.625, 1.25, 2.5, 5 and 10 mg/ml in vitro. Albendazole and distilled water were used as positive and negative control, respectively. In vitro treatment of adult worms revealed concentration and time-dependent efficacy of the fractions of E. elephantina. The aqueous and ethyl acetate fractions showed a highly significant (P<0.05) motility inhibition at concentrations of 2.5 mg/ml and above after 6 h of exposure, while the hexane fraction showed a significant (P<0.05) motility inhibition at concentrations of 5 mg/ml and above. After 30 h of exposure, all the fractions showed insignificant (P>0.05) inhibition of motility. The fractions of E. elephantina also showed mortality indexes that were not significantly different to each other, as well as to the commercial drug (albendazole). Overall, the ethyl acetate and the aqueous fractions were found to possess the highest anthelmintic activity. We therefore recommend future studies to further investigate effective dosages of these fractions in vivo, as well as a full investigation into the compounds responsible for the biological activity.

Effect of feeding bioactive forages on infection and subsequent development of Haemonchus contortus in lamb faeces

Contrasting dried herbage diets were offered to lambs to evaluate their effects on Haemonchus contortus infection and on subsequent development of larvae in faeces. Artificially infected lambs (n=24, 4 months old) were allocated to one of four treatment groups (n=6) and fed on hay of lucerne (Medicago sativa; Lu), sulla (Hedysarum coronarium; Su), sainfoin (Onobrychis viciifolia; Sa) or wormwood (Artemisia absinthium; Wo) included as 20% in ground lucerne pellets. While voluntary intake was similar, lamb growth rates were notably affected by diet. Additionally, necropsies carried out 30 days post-infection showed that worm burden was reduced by 8 (Su), 13 (Sa) and 49% (Wo) with respect to that found in lambs fed on lucerne, though only the difference with wormwood was significant. Faecal egg excretion expressed on a dry matter basis was also reduced by 22 (Su), 54 (Sa) and 73% (Wo), but differences were significant only for wormwood and sainfoin, which was associated with a decrease in female fecundity. Sulla and sainfoin diets significantly reduced egg hatching rates but increased the percentage of L(3) in the faeces of the host animal, particularly in the case of sulla hay compared to other forages. Consequently, the potential risk of infection derived from faecal excretion could be notably altered. Further work is needed to validate these findings and their implications in an applied farming system.

Redberry juniper as a roughage source in lamb feedlot rations: performance and serum nonesterified fatty acids, urea nitrogen, and insulin-like growth factor-1 concentrations

Effects of replacing cottonseed hulls with dry redberry juniper leaves on performance and serum NEFA, urea N, and IGF-1 were investigated in Rambouillet lambs (n = 24, initial BW = 28.6 +/- 4.94 kg). In a study with 2 feeding periods (period 1 = 65% concentrate ration, 28 d; period 2 = 85% concentrate ration, 49 d), lambs were individually fed ad libitum treatment diets containing cottonseed hulls (control; CSH), one-half of the cottonseed hulls replaced by dry juniper leaves (CSHJ), or all the cottonseed hulls replaced by dry juniper leaves (JUN). Lamb BW was similar on d 0 and 14, but increasing juniper in the diet linearly reduced (P = 0.04) BW on d 28. Differences in BW during period 1 are attributed to ADG and average daily DMI linearly decreasing (P < 0.001) with increasing concentrations of juniper, with lambs fed CSH, CSHJ, or JUN diets having ADG of 0.34, 0.30, and 0.14 kg, respectively. Differences in average daily DMI are attributed to secondary compounds in the cottonseed hulls and juniper and nutrient-toxin interactions. Lambs fed CSHJ diets had the greatest (P = 0.04) G:F compared with lambs fed CSH and JUN during period 1. Lambs fed JUN diets tended to have the greatest (P = 0.09) NEFA concentrations during period 1, and increasing juniper in the diet linearly reduced (P = 0.006) serum urea N and IGF-1 on d 14 and 28, respectively. During period 2, intake and growth of lambs fed JUN diet rapidly increased, resulting in all lambs having similar ADG, DMI, G:F, and BW. When period 2 began (d 33), serum NEFA and urea N were similar (P > 0.12) among lambs, but serum IGF-1 tended to be linearly reduced (P = 0.09) by increasing juniper in the diet. At times during period 2, lambs fed CSHJ had the greatest (P < 0.02) serum urea N (d 40 and 82) and IGF-1 (d 54) concentrations. Results were interpreted to indicate that air-dried redberry juniper leaves can replace all of the cottonseed hulls in lamb feedlot rations. Feeding 30% juniper in the diet for a longer period of time during the initial feeding period probably would have further reduced growth performance.

Supplements containing Acacia karroo foliage reduce nematode burdens in Nguni and crossbred cattle

The objective of this study was to compare nematode worm burdens in Nguni and crossbred cattle supplemented with Acacia karroo leaf meal. Eighteen Nguni (274.4 ± 17.34 kg) and 12 crossbred (230.5 ± 14.62 kg) steers aged 19 months were allocated to three dietary treatments: A. karroo leaf meal, sunflower cake and control with no supplement. Steers in all the treatments grazed on natural pasture whereas those on A. karroo leaf meal and sunflower cake diets were given an additional 1.5 kg and 650 g of feed, respectively, to supply 150 g of protein per day for 60 days. Faecal samples collected from the steers’ recta every fortnight were examined for nematode egg types using the modified McMaster technique. At slaughter, the abomasa and intestines were collected, opened and washed for worm identification. Nguni steers supplemented with the A. karroo leaf meal diet had the lowest mean strongyles egg counts and mean total egg counts (P < 0.05). Steers that received the A. karroo leaf meal and sunflower cake diets had lower Haemonchus contortus and Oesophagostomum colombianum worm burdens than those that received the control diet (P < 0.05). Mean strongyles and Strongyloides egg counts, and H. contortus and Oes. colombianum worm counts were negatively correlated with average daily gain and body condition scores (P < 0.05). Generally, Nguni cattle supplemented with A. karroo leaf meal had the lowest egg loads and worm burdens. It was concluded that supplementing cattle with A. karroo could reduce nematode burdens.