Evaluation of nutraceutical properties of Leucaena leucocephala leaf pellets fed to goat kids infected with Haemonchus contortus

Background

Leucaena leucocephala, as a shrub legume rich in condensed tannins, is a candidate for the integrated control of gastrointestinal parasitic pathogen nematodes. Here, we investigated the anthelmintic potential of the nutraceutical L. leucocephala, transformed into pellets, against Haemonchus contortus.

Results

Creole goat kids were fed an iso-nitrogenous diet of Dichantium hay with alfalfa pellets or Leucaena pellets or an alfalfa–leucaena mixture in varying ratios. The artificial infection of kids with H. contortus led to infection levels comparable to those observed in the farm environment on the basis of egg excretion. The anthelmintic activity of Leucaena, compared to alfalfa, was demonstrated by its potential to reduce egg excretions (1524 vs. 3651 eggs/g) and the larval development of excreted eggs (3.5 vs. 24%). This anthelmintic potential was reported when the ratio of Leucaena incorporation in the diet was high (50% DM intake). The voluntary dry matter intake (79.3 vs. 77.0 g Large Weigth^0.75), the total tract dry matter digestion (0.585 vs. 0.620), and the growth (57.1 vs. 71.3 g/d) of kids fed Leucaena compared to alfalfa indicate that Leucaena has a high feed value. The Leucaena, even at the highest intakes in the diets, has not shown any signs of poisoning in kids.

Conclusions

Leucaena fulfilled the conditions to be a good nutraceutical, and pelleting is a good method for its use.

In vitro acaricidal activity of Cymbopogon citratus, Cymbopogon nardus and Mentha arvensis against Rhipicephalus microplus (Acari: Ixodidae)

The chemical composition and acaricidal activity of plant-derived essential oils was assessed against Rhipicephalus microplus ticks. The essential oils of Mentha arvensis, Cymbopogon citratus and C. nardus were assessed for acaricidal activity against Rhipicephalus microplus. Essential oils (EO) of plants were separated by hydrodistillation (three times) and analyzed using gas chromatography - mass spectrometer (GC-MS). For bioassays, engorged females of R. microplus were exposed to C. citratus and C. nardus EO at 2%, 3%, 4% and 5% concentrations; and to M. arvensis EO at 1%, 3%, and 5% for 5 min. The weight egg mass, nutrient index (N.I), egg production index (E.P.I), hatching and control rate were evaluated. Non-feed larvae of R. microplus were exposed to essential oils with 0.25%, 0.5%; 1%; 1.5% and 2% concentrations; the mortality rate was measured after 48 h. Only engorged females presented reduced biological activities (oviposition, E.P.I) after exposure to M. arvensis at 3%, when in comparison to both positive and negative controls. The hatchability of R. microplus larvae ranged from 66.9% (after exposure to C. nardus EO at 5%) to 99.2% (positive control). The nutrition index was lower (46.6%) for the exposure to M. arvensis EO at 5%. M. arvensis at 3% and 5% concentrations was significantly efficient for engorged females when compared to control (53.7% and 47.5%, respectively). C. citratus EO at 1%, 1.5% and 2% concentrations yielded better results in the larval packet test, causing 100% mortality. Nonetheless, C. nardus and M. arvensis EO at 2% yielded 66% and 39% mortality, respectively. The study showed that M. arvensis presented potential for the control of R. microplus engorged females while C. citratus and C. nardus presented potential as a larvicide.

Dichanthium hay combined with green cassava foliage or pelleted cassava foliage as fed for Black Belly rams

Intake, digestion and nitrogen retention were measured in fifteen 1-year-old Black Belly rams that had an average weight of 35.3 (± 1.59) kg and that consumed mixed diets. Diets consisted of old Dichanthium spp. hay distributed ad libitum, combined with 500 g (dry matter basis) of green or pelleted cassava foliage. Alfalfa pellets were used as a control for foliage supplement. The experiment was run in a 3 × 3 Latin square design. Total dry matter intake was lower (P < 0.05) with the green foliage cassava diet compared with the alfalfa pellet diet. Differences were not significant (P < 0.12) with the green cassava foliage diet compared with the cassava foliage pellet diet. Total tract digestion of organic matter, crude protein and cell wall components in cassava green foliage and cassava foliage pellet diets were significantly lower than in the alfalfa diet. Crude protein total tract digestion was similar for cassava green foliage and cassava foliage pellet diets, while fibre digestion was lower with cassava green foliage diets. Retained nitrogen was significantly higher with the alfalfa diet compared with cassava diets-between which there were no differences. Urinary nitrogen excretion was similar between all diets. In conclusion, pelleting does not decrease the feed value of cassava foliage, but this value is nevertheless lower than the feed value of alfalfa.

Effectiveness of several anthelmintics to control a Strongyloides sp. outbreak in Creole-de-Guadeloupe male kids aged 7 months

Routine faecal examination of a herd of weaned male goats revealed heavy infections with gastrointestinal strongyles (GIS) and Strongyloides sp. Moxidectin (routinely dosed at 0.3 mg·kg^-1, i.e., 1.5 times the sheep dose), although fully effective against GIS, failed to control Strongyloides sp., with an estimated faecal egg count reduction (FECR) of only 55.5%. In addition, levamisole (11.25 mg·kg^-1) and ivermectin (0.3 mg·kg^-1) also failed to control Strongyloides sp., with FECRs of 1.4% and 53.5%, respectively. On the other hand, albendazole (7.5 mg·kg^-1) and netobimin (11.25 mg·kg^-1 and 22.5 mg·kg^-1) reduced by 96.3-99.9% the Strongyloides sp. faecal egg counts according to dose and remained effective, although, in the past, this drug family has been used extensively on the same farm and was no longer effective against GIS. Albendazole or netobimin at 3 times the dose for sheep may be effective for Strongyloides sp. control in case of severe infection.

Comparative response of IgA and IgG activity and hematological parameters among four main beef-cattle breeds infected with gastrointestinal nematodes in the warm humid tropic of Mexico

This study determined the immunoglobulin (A and G) activity against gastrointestinal nematodes (GIN) and also the hematological parameters in four beef-calf breeds naturally infected in a tropical region of Mexico. Thirty-six infected calves were used to determine the fecal nematode egg counts (FEC), the IgA and IgG activity in serum and saliva, the packed cell volume (PCV), the plasmatic protein (PP) and the differential leukocyte counts. These parameters were measured for a five-month period. ELISA assay was performed using adult worm crude antigen (AWCA) from Haemonchus contortus, Trichostrongylus colubriformis, Mecistocirrus digitatus and Cooperia punctata. The variables were analyzed using a fixed model according to the breed group. The FEC records (means ± standard deviation) for the different breeds were: Brangus (122±115), Charolais (391±507), Guzerat (294±326) and Brown Swiss (413±395). No statistical differences (P>0.05) were found among breeds. Cooperia and Haemonchus were the main identified genera in the coprocultures. Differences in hematological parameters were observed among breeds (P<0.01); Guzerat showed the highest PCV (42.6±4.7%). The lowest leukocyte counts were observed in the Charolais breed (9.2±2.4 × 109 cells L-1). Differences between Guzerat and Charolais were only detected in eosinophils, neutrophils and lymphocytes. Increased activity of IgA was observed against M. digitatus (21% OD) compared with the response against C. punctata in serum samples (13% OD). The lowest IgA activity in serum and saliva was found in Guzerat calves. Charolais and Brown Swiss showed the highest IgA activity in serum and the highest value in saliva was found in Brangus.

Potential of tannin-rich plants for modulating ruminal microbes and ruminal fermentation in sheep

The objective of this work was to study nutritional strategies for decreasing methane production by ruminants fed tropical diets, combining in vitro and in vivo methods. The in vitro approach was used to evaluate the dose effect of condensed tannins (CT) contained in leaves of Gliricidia sepium, Leucaena leucocephala, and Manihot esculenta (39, 75, and 92 g CT/kg DM, respectively) on methane production and ruminal fermentation characteristics. Tannin-rich plants (TRP) were incubated for 24 h alone or mixed with a natural grassland hay based on Dichanthium spp. (control plant), so that proportions of TRP were 0, 0.25, 0.5, 0.75, and 1.0. Methane production, VFA concentration, and fermented OM decreased with increased proportions of TRP. Numerical differences on methane production and VFA concentration among TRP sources may be due to differences in their CT content, with greater effects for L. leucocephala and M. esculenta than for G. sepium. Independently of TRP, the response to increasing doses of CT was linear for methane production but quadratic for VFA concentration. As a result, at moderate tannin dose, methane decreased more than VFA. The in vivo trial was conducted to investigate the effect of TRP on different ruminal microbial populations. To this end, 8 rumen-cannulated sheep from 2 breeds (Texel and Blackbelly) were used in two 4 × 4 Latin square designs. Diets were fed ad libitum and were composed of the same feeds used for the in vitro trial: control plant alone or combined with pellets made from TRP leaves at 44% of the diet DM. Compared to TRP, concentration of Ruminococcus flavefaciens was greater for the control diet and concentration of Ruminococcus albus was least for the control diet. The methanogen population was greater for Texel than for Blackbelly. By contrast, TRP-containing diets did not affect protozoa or Fibrobacter succinogenes numbers. Hence, TRP showed potential for mitigating methane production by ruminants. These findings suggest that TRP fed as pellets could be used to decrease methane production.

Potential of tannin-rich plants, Leucaena leucocephala, Glyricidia sepium and Manihot esculenta, to reduce enteric methane emissions in sheep

An in vivo trial was conducted in sheep to investigate the effect of three tropical tannin-rich plants (TRP) on methane emission, intake and digestibility. The TRP used were leaves of Glyricidia sepium, Leucaena leucocephala and Manihot esculenta that contained, respectively, 39, 75 and 92 g condensed tannins/kg DM. Methane was determined with the sulphur hexafluoride tracer technique. Eight rumen-cannulated sheep of two breeds (four Texel, four Blackbelly) were used in two 4 × 4 Latin square designs. Four experimental diets were tested. They consisted in a tropical natural grassland hay based on Dichanthium spp. fed alone (C) or in association with G. sepium (G), L. leucocephala (L) or M. esculenta (M) given as pellets at 44% of the daily ration. Daily organic matter intake was higher in TRP diets (686, 984, 1054 and 1186 g/day for C, G, L and M respectively; p < 0.05) while apparent organic matter total tract digestibility was not affected (69.9%, 62.8%, 65.3% and 64.7% for C, G, L and M respectively; p > 0.05). Methane emission was 47.1, 44.9, 33.3 and 33.5 g/kg digestible organic matter intake for C, G, L and M, respectively, and was significantly lower (p < 0.05) for L and M than for G and C. Our results confirm the potential of some TRP to reduce methane production. The strong decrease in methane and the increase in intake with TRPs may be due to their presentation as pellets.

Effect of selective anthelmintic treatments on health and production parameters in Pelibuey ewes during lactation

A study was conducted from December to April 2013, with the aim of evaluating a system of selective antiparasitic treatments using the FAMACHA© color chart compared with a conventional suppressive deworming system every 30 days in Pelibuey ewes during lactation. For the study, 54 ewes were used. They were randomly divided into two groups: FAMACHA and chemical treatments. The ewes in the first group received selective treatment depending on the ocular mucosa coloration (FAMACHA) and body condition score (BCS), while in the second group (chemical) all the animals remained under routine deworming every 30 days. Fecal nematode egg counts, proportion of third-stage trichostrongylid larvae, body condition, coloration of the ocular mucosa, and packed cell volume in the ewes were determined, while in lambs only body weight (BW) was recorded. No significant differences (p > 0.05) were observed in any of the studied variables between groups; however, the use of antiparasitic drugs was reduced during the experimental period in the FAMACHA group and no deaths of lambs or ewes were recorded. The results indicate that during the lactation of ewes, a strategy of selective treatments can be implemented without showing deterioration in major health and productive parameters of these animals.

In vitro effects of Cassava (Manihot esculenta) leaf extracts on four development stages of Haemonchus contortus

Three extracts (aqueous, methanolic and dichloromethane) of Manihot esculenta (Cassava) leaf were tested in vitro on four development stages of Haemonchus contortus using egg hatch assay (EHA), larval development assay (LDA), L3 migration inhibition assay (LMI) and adult worm motility assay (AWM). Compared to the negative control, significant effects (P<0.0001) were observed for the methanolic extract of leaf against larval development (57.6% +/-7.6), with a dose dependent effect. These results suggest that Cassava possess anthelmintic activity against H. contortus. The active principles responsible for the activity could be the terpenoids and condensed tannin compounds present in the leaf.

The effects of replacing Dichantium hay with banana (Musa paradisiaca) leaves and pseudo-stem on carcass traits of Ovin Martinik sheep

A study was done to evaluate banana (Musa paradisiaca) as a forage (leaves and pseudo-stems) for feeding Ovin Martinik lambs (OMK), with the aim to test its impact on carcass quality. Forty four intact OMK male were used after weaning with an initial mean live weight of 14.4 (+/- 3.3) kg, reared in individual pens. Animals were offered either Dichantium hay (control diet, Dh) or cut chopped leaves and pseudo-stems of banana (experimental diet, Blps). They were fed 200-250 g x d(-1) of commercial concentrate. Lambs were slaughtered according to 3 classes of slaughter weight (SW): SW20, SW23 and SW26. Growth and carcass performances of both groups were not significantly different, 77 vs. 81 g x d(-1) and 42% vs. 43% hot carcass yield, for Dh vs. Blps, respectively. There was a significant (P < 0.05) decrease (31.0 vs. 29.7%) for the dry matter content of the shoulder for lambs fed the banana diet. However, there was no effect observed for the other chemical component (CP, lipid and mineral 585, 317 and 95 g x kg(-1) DM, respectively). The shoulder (20% of the carcass whatever the SW) was precocious as demonstrated by the allometry coefficient relative to carcass weight (0.894) significantly (P < 0.01) less than 1. It was concluded that, the use of Blps had no significant effect on growth, carcass weights and yields of the OMK lambs, irrespective of the class of the slaughter weight. From these initial results, the use of banana foliages and pseudo-stems could be recommended as sources of forages.