The in vitro rumen exsheathment test for studying the effect of plant extracts on the exsheathment of Haemonchus contortus infective larvae.

This study applied the in vitro rumen exsheathment test (IVRET) to evaluate the exsheathment kinetics of Haemonchus contortus infective larvae (L3) incubated in ruminal liquor (RL) containing acetone:water extracts of Acacia pennatula (AP), Gymnopodium floribundum (GF), Havardia albicans (HA) or Lysiloma latisiliquum (LL). The role of polyphenols in the biological activity of the evaluated extracts was also determined. Larvae were incubated in RL either alone or added with a different plant extract (AP, GF, HA, or LL) at 1200 µg/mL. Polyethylene glycol (PEG) was added to block polyphenols in each treatment (RL+PEG, AP+PEG, GF+PEG, HA+PEG, and LL+PEG). After incubation times of 0, 1, 3, 6, 9, and 24 h, the exsheathment process was stopped to count the number of ensheathed and exsheathed L3. A Log-Logistic model was used to determine the L3 exsheathment kinetics in the different RL treatments. The inflection point of the respective kinetic curves, which indicates the time to reach 50 % exsheathed L3 (T50), was the only parameter that differed when comparing the exsheathment models (99 % probability of difference). The T50 values obtained for GF, HA, and LL treatments (T50 = 7.11 - 7.58 h) were higher in comparison to the T50 of RL (5.72 h) (≥ 70 % probability of difference). The L3 incubated in RL added with GF, HA, and LL extracts delayed their exsheathment at 3 and 6 h of incubation (28.71 - 48.06 % exsheathment reduction) compared to the RL treatment. The T50 value for AP, AP+PEG, GF+PEG, HA+PEG, and LL+PEG were similar to RL and RL+PEG (T50 = 5.34 - 6.97 h). In conclusion, the IVRET can be used to identify plants with the potential to delay the exsheathment of H. contortus L3 in the ruminal liquor. The acetone:water extracts of G. floribundum, H. albicans, and L. latisiliquum delayed the T50 of H. contortus exsheathment, which was evident at 3 and 6 h of incubation in ruminal liquor. The observed exsheathment delay was attributed to the polyphenol content of the extracts.

Adapting the in vitro rumen incubation method to evaluate the effect of a plant extract on the exsheathment inhibition of Haemonchus contortus infective larvae.

This study adapted the in vitro rumen incubation (IVRI) method to evaluate the biological activity of a Gymnopodium floribundum leaves extract against the exsheathment of Haemonchus contortus infective larvae (L3), and to determine the role of plant polyphenols on the biological activity. The incubation protocol followed the IVRI method, adding polyethylene glycol (PEG) as a polyphenol-blocking agent. The L3 were incubated in ruminal liquor (RL), ruminal liquor with PEG (RL+PEG), ruminal liquor with G. floribundum extract (RLE), and ruminal liquor with G. floribundum extract and PEG (RLE+PEG). Incubation condition controls included phosphate buffered saline (PBS), PBS with PEG (PBS+PEG), incubation medium (without ruminal liquor) (IM), and incubation medium with PEG (IM+PEG). The L3 were recovered after incubation times of 0, 1, 3, 6, 9, and 24 h (39 °C). The respective L3 exsheathment kinetics were estimated for the different treatments (RL, RL+PEG, RLE, and RLE+PEG) using Log-Logistic models. The parameters of the different models were compared to determine the impact of the extract, with or without PEG, on the L3 exsheathment kinetics. The exsheathment in PBS and PBS+PEG remained < 2.71% at each incubation time. The exsheathment in IM and IM+PEG reached 13.58% and 17.18% at 24 h, respectively. The exsheathment percentages for RLE were lower than those for RL at 3, 6 and 9 h of incubation. The inflection point, indicating the time required to reach 50% of the maximal exsheathment (T50), was the only parameter that differed between the ruminal liquor models. The T50 in RLE (7.106 h) was higher than the values obtained for RL (5.385 h) and RL+PEG (4.923 h) (99.99% probability of being different). Such delay resulted in a reduction of exsheathment in RLE of 62% at 3 h, 38% at 6 h, and 12% at 9 h, relative to RL values. When PEG was added with the extract (RLE+PEG), the T50 (5.045 h) was similar to that of RL and RL+PEG. The IVRI method was adapted as an in vitro rumen exsheathment test (IVRET). The IVRET showed that H. contortus L3 exposed to G. floribundum extract delayed their exsheathment kinetics at different time points. The exsheathment delay was attributed to the polyphenol content of the extract.

An in vitro rumen incubation method to study exsheathment kinetics of Haemonchus contortus third-stage infective larvae.

This study developed and evaluated an in vitro rumen incubation (IVRI) method to describe the exsheathment kinetics of Haemonchus contortus third-stage infective larvae (L3) in ruminal liquor (RL). The specific objectives were (i) to standardize the IVRI method to facilitate the contact between L3 and RL as well as the larval recovery, and (ii) to apply the IVRI method to describe the exsheathment kinetics of H. contortus and to select the best fitting nonlinear model. Incubation devices containing H. contortus larvae were incubated according to the IVRI technique in cattle RL or PBS. The incubation conditions included RL mixed with a nitrogen-rich media, maintained at 39 °C, with pH = 7.0, vented with CO2 and manual agitation. The larvae were recovered after 0, 1, 3, 6, 9, 12, and 24 h. The exsheathed and ensheathed larvae were counted to estimate the exsheathment (%) in RL or PBS. Exsheathment in RL was analyzed with nonlinear regression models: Exponential, Gompertz, Logistic, Log-Logistic, and Weibull. The models' fit was compared to select the one that best described the exsheathment kinetics. The exsheathment in RL reached 6.52%, 20.65%, 58.22%, 69.24%, 73.08%, and 77.20% in 1, 3, 6, 9, 12, and 24 h, respectively. Although the Gompertz, Weibull, and Logistic models were adequate to describe the observed exsheathment, the Log-Logistic model had the best fit. The IVRI method using bovine RL represents a suitable tool for the study of the in vitro exsheathment kinetics of H. contortus L3.

Composition of Slow-Growing Male Chicken's Meat and Bone Quality as Affected by Dietary Moringa oleifera Lam. Meal.

This study investigated the impact of Moringa oleifera Lam. meal (MOM) on meat nutritional properties and bone quality of slow-growing layer-type male chickens raised in semi-intensive conditions. A total of 198, 72-d-old Dominant Blue D 107 male chickens, with an average weight of 1093 ± 15.2 g, were randomly assigned to three dietary treatments supplemented with 0, 3, and 6% of MOM that corresponded to T1, T2, and T3, respectively. Each treatment, consisting of six replicated floor pens of 11 birds, had access to the outdoors for 49 days. The results showed that breast muscle ash percentage was significantly greater (P ≤ 0.05) in T2 in comparison to the T1 group. Meat dry matter, protein, and fat content were not influenced by the treatments (P > 0.05). Regardless of the treatments, oleic acid (C18:1N9C) was numerically more abundant in the breast than in the leg muscle. Alternatively, femoral and tibial lengths were shorter (P ≤ 0.05) in birds fed 3% MOM than the two other groups. Moreover, birds fed with MOM had greater tibial diameter (P ≤ 0.05) than those that were fed without MOM. In addition, bone ash content and phosphorous amount were significantly higher (P ≤ 0.05) in birds fed 6% MOM compared to those fed without MOM. The data of this study indicate that up to 6% of MOM may be added to the diet of slow-growing layer-type male chickens raised with outdoor access under tropical conditions to improve bone quality traits.

Selection of Forage Resources by Juvenile Goats in a Cafeteria Trial: Effect of Browsing Experience, Nutrient and Secondary Compound Content.

We evaluated the effect of browsing experience, nutritional quality and secondary compounds of forage resources, and the interaction between these factors on the selection and intake of goats in a cafeteria trial. Twelve juvenile Criollo goats from 7 to 9 months of age, weighing 22 ± 3 kg, were divided into two groups: (a) browser goats group (n = 6, BG), and (b) naïve goats group (n = 6, NG), formed according to their previous browsing experience (with and without, respectively). Animals were housed in individual pens. The cafeteria experiment lasted 21 days considering pen adaptation, foliage adaptation, and measurements, which included the selection index (SI) of experimental forage resources (Chesson's alpha) and their dry matter intake (DMI/Kg0.75), using a multiple Latin square design. Furthermore, correlation and regression analyses were used to assess the relationship between the aforementioned factors. The NG did not show any selection pattern, while the BG selected Piscidia piscipula and Senegalia gaumeri (p = 0.0002). The BG consumed smaller amounts of secondary compounds compared to NG (p = 0.0001). In the BG, the flavonoids affected negatively their selection (R2 = 97.51, p = 0.0001), while the DMI was affected by in vitro DM digestibility and flavonoids (R2 = 99.85; p = 0.0001). For the NG, the crude protein and organic matter contents were associated with DMI, but none had a significant relationship with SI. The BG selected and consumed forages with suitable nutritional quality avoiding those with high content of secondary compounds such as flavonoids. Conversely, NG did not show a clear pattern for their selection or intake.

In vitro anthelmintic activity of five tropical legumes on the exsheathment and motility of Haemonchus contortus infective larvae.

This study investigated the in vitro anthelmintic (AH) activity of five tropical legume plants [Arachis pintoi CIAT 22160 (A.p. 22160), Gliricidia sepium, Cratylia argentea (C.a. Yacapani), C. argentea CIAT 22386 (C.a. 22386), C. argentea Veranera (C.a. Veranera)] against Haemonchus contortus infective larvae and the role of tannins/polyphenolic compounds in the AH effect. Lyophilized leaf extracts of each plant were evaluated using the Larval Exsheathment Inhibition Assay (LEIA) and the larval migration inhibition assay (LMIA). The role of tannins/polyphenolic compounds in the AH effect was evaluated in both assays using polyethylene glycol (PEG) to remove tannins from the solutions. At the highest concentration (1200µg of extract/ml), A. pintoi 22160, C.a. Yacapani, C.a. Veranera and C.a. 22386 completely inhibited the exsheathment process of H. contortus (P<0.01). At the same concentration (1200µg of extract/ml), the inhibition of larval migration for C.a. 22386, C.a. Veranera and G. sepium was 66.0%, 35.9% and 39.2% (relative to the PBS control), respectively. In both bioassays (LEIA and LMIA), the AH effect shown by each plant was blocked after the addition of polyethylene glycol (PEG), corroborating the role of tannins/polyphenolic compounds.

Comparison of two dietary markers in the determination of amino acid digestibiliy in some foodstuffs for growing broiler chickens

Se determinó la digestibilidad ileal aparente de aminoácidos en maíz, sorgo, pasta de soya, gluten de maíz, harina de pescado, harina de carne y hueso, y salvado de trigo en pollos de engorda, utilizando dióxido de titanio y óxido de cromo como marcadores inertes de la dieta. Doce pollos fueron alimentados en dos ocasiones con 30g de cada ingrediente, con uno de los dos marcadores dietéticos, mediante la técnica de alimentación forzada. Se llevaron a cabo análisis de varianza con los resultados para determinar efectos de ingredientes y de marcadores. Se encontraron diferencias significativas en la digestibilidad de aminoácidos entre ingredientes, cuyo rango fue de 0,53 para cisteína en la harina de carne y hueso, hasta 0,97 para tirosina en pasta de soya. En todos los ingredientes los coeficientes de digestibilidad de aminoácidos calculados con base en titanio fueron mayores (P<0,05) que aquellos determinados con base en cromo. La excepción fue para salvado de trigo donde no se encontró efecto significativo del marcador utilizado (P>0,05). Los coeficientes de digestibilidad de aminoácidos mostraron una menor variación cuando el dióxido de titanio fue usado como marcador dietético. Se concluye que el dióxido de titanio es más confiable que el cromo como marcador dietético, siendo menos variable y obteniéndose mayor digestibilidad, lo cual indica una mayor recuperación

Determinación de L-canavanina por cromatografía líquida de alta resolución en fase reversa y por colorimetría / Measurement of L-canavanine by reverse phase high performance liquid chromatography and by an spectrofotometric method

Introducción. Para estudiar la toxicidad y el efecto metabólico de la canavanina en animales o plantas se depende de la disponibilidad de métodos sensibles, específicos y rápidos de análisis. Materiales y métodos. Se desarrolló un método para medir la concentración de L-canavanina por cromatografía líquida en fase reversa utilizando DABS-C1 como agente de derivación y se compararon los resultados con aquellos obtenidos por colorimetría por el método de Rosenthal. Cinco muestras de canavalia fueron utilizadas para validar la técnica. Resultados y discusión. La derivación con DABS-C1 permitió la determinación de éste aminoácido sin interferencia con otros aminoácidos. No se encontraron diferencias entre las concentraciones de L-canavanina en granos de Canavalia ensiformis cuando se midió por estos 2 métodos. El análisis colorimétrico puede ser empleado como una herramienta confiable de primera elección. Debido al alto costo que involucra el análisis por HPLC deberá ser empleado cuando exista evidencia de interferencia en el método colorimétrico de compuesto y/o metabolitos presentes en la muestra