Técnicas bibliométricas para la autoevaluación de los grupos de investigación de la Universidad Autónoma de Yucatán, México

En este trabajo se presenta la metodología empleada en la autoevaluación de los Cuerpos Académicos del Campus de Ciencias Biológicas y Agropecuarias de la Universidad Autónoma de Yucatán, México, a través de parámetros cuantitativos que permitieron visualizar la calidad y cantidad de la producción académica. Para llevar a cabo dicha autoevaluación se empleó información bibliométrica obtenida de la base de datos Scopus©, del período enero 2000 a julio 2016. Se concluye que la metodología propuesta en este estudio puede ser útil para optimizar procesos de planeación y mejora continua de los cuerpos académicos de universidades públicas de México, así como utilizar en estudios futuros la metodología cualitativa para mejorar el proceso de autoevaluación

¿La suplementación energética de las ovejas puede influenciar el desempeño conductual de sus corderos neonatos?

The present work evaluated the effect of an energetic supplement (an extra 15% of the requirement) intake during the last month of gestation on the suckling behavior of neonatal lambs born from these ewes. The study was performed in a semi-intensive and commercial flock under hot sub humid tropical conditions. 12 Pelibuey ewes and their 20 newborn lambs were included. Five lamb behaviors were evaluated: number of vocalizations (NV), attempts to stand up (ASU), latency to keep stands (LKS), started looking for the udder (SLU) and achieved an effective suckling (AES). Twelve lambs conformed the control group [CG] and came from seven ewes which received an energetic supplementation of 7.37 megajoules of metabolizable energy per day (MJ EM/d). Likewise, eight lambs conformed the treatment group [TG] and came from five ewes which received a high energetic supplementation of 10.85 MJ EM/d. Both groups of ewes gave birth simultaneously. Response variables were initially categorized in low-or-high intensity using their quartile distribution and considering the median value as the reference point and analyzed post-hoc with the Fisher test. Behaviors of high and low intensity in lambs were similar in four of the five variables observed for both treatments. A significant difference was observed in the frequency of ASU, in lambs born from treated ewes when compared with lambs born from control ewes (P = 0.0281). The present results suggest that under semi-extensive breeding systems, the extra supplementation of ewes at 15 % of their energetic requirements during the last pregnancy month is reflected just in a slight improvement of the lamb’s behaviors.El presente trabajo evaluó el efecto del consumo de un suplemento energético (15 % extra del requerimiento) durante el último mes de gestación sobre la conducta de amamantamiento de los corderos neonatos nacidos de estas ovejas. El estudio se realizó en una granja comercial semi-intensiva bajo condiciones tropicales cálidas subhúmedas. Se incluyeron 12 ovejas Pelibuey y sus 20 corderos recién nacidos. Se evaluaron cinco conductas del neonato: número de vocalizaciones (NV), intentos para ponerse en pie (IQP), latencia para ponerse pie (LDP), comienzo de la búsqueda de la ubre (BU) y amamantamiento efectivo (AE). Doce corderos conformaron el grupo control [GC] y provenían de 7 ovejas que recibieron una suplementación energética de 7.37 mega julios de energía metabolizable por día (MJ EM/d). Por su parte, ocho corderos conformaron el grupo tratado [GT] y provenían de 5 ovejas que recibieron una suplementación energética alta (10.85 MJ EM/d). Ambos grupos parieron de manera simultánea. Las variables de respuesta fueron inicialmente categorizadas como de baja o alta intensidad utilizando la distribución de sus cuartiles y considerando el valor de la mediana como punto de corte y analizadas post-hoc a través de la prueba de Fisher. Las conductas de alta y baja intensidad de los neonatos fueron similares en cuatro de los cinco comportamientos observados en ambos tratamientos. Se observó una diferencia significativa en la frecuencia de intentos para ponerse de pie en los corderos de ovejas tratadas comparados a los corderos de ovejas control (P = 0.0281). Estos resultados sugieren que en sistemas de crianza semi-intensivos, la suplementación extra del 15 % de las madres durante el último mes de gestación solo se refleja en una ligera mejoría de las conductas de sus neonatos

In vitro susceptibility of ten Haemonchus contortus isolates from different geographical origins towards acetone:water extracts of two tannin rich plants

The aim of the study was to examine the variation in the in vitro susceptibility of ten Haemonchus contortus isolates from different geographical origins using respective egg hatch assays (EHA) with acetone:water extracts of two tannin containing plants, chimay (Acacia pennatula) and sainfoin (Onobrychis viciifolia). Fresh eggs were incubated in PBS with different concentrations of each extract (0, 600, 1200, 2400, 3600, 5000 and 8000μg/ml PBS). Additional concentrations were tested for O. viciifolia (75, 100, 200 and 400μg/ml PBS). Effective concentrations 50% (EC50), with the corresponding 95% confidence interval (95% CI), were calculated for every isolate with both extracts. Moreover, a resistance ratio (RR) was calculated to compare the isolates, using the most susceptible isolate for each extract as the respective reference. A second set of incubations were made using polyvinylpolypyrrolidone (PVPP) (0, 5000μg/ml, 5000μg/ml+PVPP) to determine the influence of polyphenols on the AH effect. The proportion of morulated eggs, eggs with L1 larvae failing eclosion (%LFE), and emerged larvae were estimated at different extract concentrations. Data of each isolate was used to calculate the effective concentration 50% (EC50) for each extract. The EC50 of each isolate was used to determine resistance ratio (RR) for the different isolates. For the 2 extracts, a susceptibility variation in egg hatching was observed for the different H. contortus isolates. The EC50 values for A. pennatula ranged from 2203 to 14106μg (RR from 2.01 to 6.40). The O. viciifolia extract showed higher variability with EC50 values ranging from 104 to 4783μg (RR from 3.66 to 45.74). The main AH effects of the two extracts tested on the ten isolates consisted in blocking the emergence of L1 larvae (higher% LFE). Additional observations on emerged larvae showed that extract exposure caused alterations in the internal structure, separating the cuticle from the pharynx, bulb and intestinal cells. The use of PVPP revealed that (a) condensed tannins were not the sole plant secondary metabolites responsible for the AH effects, and (b) different H. contortus isolates showed variability in the role of tannins either on the ovicidal effect or the %LFE

Susceptibility of ten Haemonchus contortus isolates from different geographical origins towards acetone:water extracts of polyphenol-rich plants. Part 2: Infective L 3 larvae

This study explored the variation in susceptibility to acetone:water plant extracts between infective larvae (L3) of ten Haemonchus contortus isolates from different geographical origin. The L3 of 10 different isolates were exposed either to the acetone:water extract of a temperate plant (Onobrychis viciifolia) or a tropical plant (Acacia pennatula) and were evaluated with the larval exsheathment inhibition assay (LEIA). The L3 of each isolate were incubated with different concentrations of each extract (0, 25, 50, 100, 200, 400, 600, 800, 1000 and 1200μg/mL of phosphate buffered saline (PBS)). After incubation, the exsheathment process of L3 was induced using a solution with sodium hypochlorite (2%) and sodium chloride (16.5%). The proportion of exsheathed L3 was determined for each concentration at 0, 20, 40 and 60min. Effective concentrations 50% (EC50) and the corresponding 95% confidence intervals (95% CI) were calculated for every isolate with both extracts. Moreover, a resistance ratio (RR) was calculated for each extract to compare isolates, using the most susceptible isolate as the respective reference for each extract. To determine the role of polyphenols on the reported effect, a second set of incubations was made for each isolate and each extract, using the extracts at a concentration of 1200μg/mL PBS with or without polyvinylpolypyrrolidone (PVPP), a polyphenol blocking agent, and controls without extract. The ten different H. contortus isolates showed variation in susceptibility for each of the 2 extracts tested (P<0.05). The EC50 values for A. pennatula extract ranged from 36 to 501μg/mL (RR: 2.11–13.68). Meanwhile, the EC50 values for O. viciifolia extract ranged from 128 to 1003μg/mL (RR: 1.25–7.82). The use of PVPP revealed that polyphenols were responsible for the anthelmintic activity recorded for both extracts. However, tested H. contortus isolates suggested that susceptibility to one polyphenol-rich extract did not determine the susceptibility to the other polyphenol rich extract. The latter result indicated that the different H. contortus isolates varied in their susceptibility to the polyphenols present in each extract evaluated

Variabilidad en el contenido de polifenoles, actividad biológica y antihelmíntica de extractos metanol:agua de las hojas de Gymnopodium floribundum Rolfe

The effect of the harvest month and age of the leaves of Gymnopodium floribundum on the content of polyphenolic compounds (total phenols (TP), total tannins (TT) and condensed tannins (CT)) of methanol:water extracts was determined. In addition, the biological activity of polyphenols measured as the ability to precipitate protein (PP), inhibit egg hatching (EH), and larval exsheathment (LEI) of Haemonchus contortus was determined. G. floribundum leaves were harvested in 4 mo of the year: December, March, June and September. Twenty-four methanol:water extracts (70:30) were obtained, 12 produced from leaves of varied age (VA) and 12 from 90-d-old leaves (A90). All extracts caused similar PP regardless of age and harvest month. EH inhibition was only significant for December VA extract (EC50 = 374.4 μg/mL; P 1,500 μg/mL in December, June and September. Although all extracts inhibited larval exsheathment (LEI), the lowest EC50 was that of the VA leaf extract of June (EC50 = 80.4 μg/mL; P 1500 μg/ml en diciembre, junio y septiembre. Aunque todos los extractos inhibieron el desenvaine larval (IDL), la menor CE50 fue la del extracto de hojas EV de junio (CE50 = 80.4 μg/ml; P<0.05). La incubación de extractos con polivinilpolipirrolidona (PVPP) limitó la IDL (P<0.05), pero los polifenoles solo explicaron parte de esa actividad. En conclusión, el contenido de TC de los extractos de hojas de G. floribundum depende de su edad y mes de cosecha. Los polifenoles mostraron actividad de PP y se asociaron parcialmente con la IDL. Sin embargo, los polifenoles no explican la actividad contra huevos de H. contortus

Potential economic impact assessment for cattle parasites in Mexico. Review

Las pérdidas económicas causadas por parásitos del bovino en México se calcularon anualmente. Los principales factores considerados para esta evaluación incluyeron el número total de animales a riesgo, los posibles efectos dañinos del parasitismo sobre la producción de leche o ganancia de peso, y los decomisos de subproductos pecuarios. Las pérdidas económicas fueron estimadas en dólares americanos (US$) y se basaron en las pérdidas del rendimiento productivo de animales no tratados. Estas estimaciones reflejan los principales efectos de seis parásitos o grupos de parásitos sobre la producción bovina. El impacto económico potencial (millones de dólares) fue: nematodos gastrointestinales US$ 445.10; coccidias (Eimeria spp.) US$23.78; duelas del hígado (Fasciola hepatica) US$ 130.91; garrapatas (Rhipicephalus microplus) US$573.61; mosca de los cuernos (Haematobia irritans) US$ 231.67; y mosca de los establos (Stomoxys calcitrans) US$6.79. En general, las pérdidas anuales causadas por los seis principales parásitos del bovino en México se estimaron en US$ 1.41 mil millones. Considerando que la población bovina nacional en 2013 fue de 32.40 millones de bovinos, la pérdida anual estimada fue de US$43.57 por animal. Se hace mención de las limitaciones que tienen el uso de algunas referencias para las estimaciones, particularmente cuando se extrapolan situaciones locales a una escala nacional. Sin embargo, el resultado general obtenido en este estudio demuestra la magnitud e importancia del parasitismo en el ganado de México y los desafíos para maximizar la rentabilidad de la industria ganadera sin recurrir al uso de estrategias de control integrado sustentable de parásitos. ABSTRACT Here, economic losses caused by cattle parasites in Mexico were estimated on an annual basis. The main factors taken into consideration for this assessment included the total number of animals at risk, potential detrimental effects of parasitism on milk production or weight gain, and records of condemnation on livestock byproducts. Estimates in US dollars (US$) were based on reported yield losses in untreated animals. These estimates reflect the major effects on cattle productivity of six parasites, or parasite group. The potential economic impact (US$millions) was: gastrointestinal nematodes US$ 445.10; coccidia (Eimeria spp.) US$23.78; liver fluke (Fasciola hepatica) US$ 130.91; cattle tick (Rhipicephalus microplus) US$573.61; horn fly (Haematobia irritans) US$ 231.67; and stable fly (Stomoxys calcitrans) US$6.79. Overall, the yearly economic loss due to the six major parasites of cattle in Mexico was estimated to be US$ 1.41 billion. Considering that the national cattle herd registered in 2013 included 32.40 million head, the estimated yearly loss per head was US$ 43.57. The limitations of some of the baseline studies used to develop these estimates, particularly when extrapolated from local situations to a national scale, are acknowledged. However, the general picture obtained from the present effort demonstrates the magnitude and importance of cattle parasitism in Mexico and the challenges to maximize profitability by the livestock industry without adapting sustainable and integrated parasite control strategies

Is there a negative association between the content of condensed tannins, total phenols, and total tannins of tropical plant extracts and in vitro anthelmintic activity against Haemonchus contortus eggs?

In vitro studies using plant extracts suggest a relationship between their polyphenol contents and their anthelmintic (AH) activity against Haemonchus contortus. High polyphenol content appears to increase the efficacy of plant extracts against H. contortus as assessed by the larval exsheathment inhibition assay (LEIA) while appearing to reduce the AH efficacy measured using the egg hatch assay (EHA). In addition, some plants lack AH activity. Therefore, the present study investigated the relationship between the contents of condensed tannins (CT), total phenols (TP), and total tannins (TT) in methanol:water extracts (70:30) obtained from ten tropical plant species consumed by small ruminants as well as their AH activity against H. contortus evaluated by LEIA and EHA. Extracts of Acacia collinsii, Lysiloma latisiliquum, Havardia albicans, Senegalia gaumeri, Mimosa bahamensis, Piscidia piscipula, Acacia pennatula, Gymnopodium floribundum, Leucaena leucocephala, and Bunchosia swartziana were examined. Positive correlations were found between the effective concentration 50% (EC50) (EHA) of extracts and their CT (r = 0.6809, P < 0.05, n = 10) and TP (r = 0.9152, P < 0.05, n = 10) content, suggesting that their concentration negatively affected AH activity against eggs. Based on the LEIA, there was no significant association between the EC50 and the CT, TP, or TT of all extracts evaluated. Thus, if sheep and goats consume a complex feed mixture with high amounts of CT, TP, and TT, it might be difficult to observe an AH effect against H. contortus egg hatching. However, the AH effect upon L3 establishment might be feasible

Bio-guided fractionation to identify Senegalia gaumeri leaf extract compounds with anthelmintic activity against Haemonchus contortus eggs and larvae

Small ruminants browsing in tropical forests readily consume the foliage of Senegalia gaumeri. A S. gaumeri methanol:water extract was recently shown to have ovicidal activity against Haemonchus contortus eggs in vitro. In the present study, the fraction of a S. gaumeri methanol:water extract with ovicidal activity against H. contortus eggs and the metabolites potentially involved in this activity were identified. Bio-guided fractionation of the S. gaumeri methanol:water extract identified high ovicidal activity (80.29%, EC50 = 58.9 μg/mL) in the non-polar sub-fraction P1. Gas chromatography-mass spectrometry (GC–MS) identified several fatty acids: pentacosane (18.05%), heneicosane (18.05%), triacontane (30.94%), octacosane (18.05%), and hexanedioic acid bis-(2-ethylhexyl) ester (32.72%). Purification of the polar components of sub-fraction P1 led to the identification of p-coumaric acid as a major constituent. In egg hatch tests, 400 μg/mL p-coumaric acid resulted in an ovicidal effect of 8.7%, a larvae failing eclosion effect of 2.9%, and of the emerged larvae (88.4%), many were damaged. In conclusion, the low AH activity of p-coumaric acid against H. contortus eggs indicates that it is not solely responsible for the ovicidal activity of sub-fraction P1 but might act in synergy with other compounds in this fraction. However, p-coumaric acid showed potential anthelmintic effects against the larval stage of H. contortus

Age of Haemonchus contortus third stage infective larvae is a factor influencing the in vitro assessment of anthelmintic properties of tannin containing plant extracts

The larval exsheathment inhibition assay (LEIA) of infective larvae (L3) is an in vitro method used to evaluate the anthelmintic (AH) activity of tannin-containing plant extracts against different species of gastrointestinal nematodes, including Haemonchus contortus. Some conditions remain to be defined in order to standardize the LEIA, i.e. the optimal age of larvae produced from donor animals to use in the assays. Therefore, this study aimed at identifying the effect of age and age-related vitality of H. contortus infective larvae produced under tropical conditions, on the in vitro AH activity measured with the LEIA. The same acetone:water (70:30) extract from Acacia pennatula leaves was used to perform respective LEIA tests with H. contortus L3 of different ages (1–7 weeks). Each week, the L3 were tested against different concentrations of extract (1200, 600, 400, 200, 100, 40μg/mL of extract) plus a PBS control. Bioassays were performed with a benzimidazole (Bz) resistant H. contortus (Paraíso) strain. In order to identify changes in L3 vitality on different weeks (1–7), two assays testing larval motility were included only with PBS: the larval migration assay (LMA) and the larval motility observation assay (LMOA). Mean effective concentrations causing 50% and 90% exsheathment inhibition (EC50, EC90) were obtained for every week using respective Probit analyses. On the first week, the larvae had lowest EC50 and EC90 (39.4 and 65.6μg/mL) compared to older larvae (P0.05), while older larvae tended to show higher EC50 and EC90 (P<0.05). Motility showed strong negative correlations with age of larvae (r≥−0.83; P <0.05) and EC50 (r≥−0.80; P<0.05), suggesting that the lower extract efficacy could be associated with decaying vitality of larvae associated with age. More stable efficacy results were found between two to five weeks of age

An in vitro approach to evaluate the nutraceutical value of plant foliage against Haemonchus contortus

Nutraceutical plants provide nutrients for the animal as well as secondary compounds that can affect the biology and survival of gastrointestinal nematodes (GIN). Current screening of nutraceutical plants is based on in vitro evidence of anthelmintic (AH) activity against different life stages of GIN, but nutritional information is omitted or scarce. This study proposes an integral in vitro screening protocol to identify the nutraceutical value of the foliage from plant species consumed by small ruminants, using Haemonchus contortus as a biological model. The leaves from Acacia collinsii, A. pennatula, Bunchosia swartziana, Gymnopodium floribundum, Havardia albicans, Leucaena leucocephala, Lysiloma latisiliquum, Mimosa bahamensis, Piscidia piscipula, and Senegalia gaumeri were evaluated for their chemical composition and in vitro digestibility. Acetone:water extracts (70:30) from leaves of each plant were evaluated using the egg hatch assay and larval exsheathment inhibition assay. Respective effective concentrations 50% (EC50) were determined for each assay. The ten plant species showed good nutritional value for ruminants, including crude protein (> 10%), metabolizable energy (> 2.9 MJ/kg DM), and varied CT content (from 1.0 to 37.6%). The best AH activity against H. contortus eggs (EC50 = 401.8 μg/mL) and L3 (EC50 = 83.1 μg/mL) was observed for S. gaumeri extract. Although all the plant species showed in vitro nutraceutical potential, the leaves of S. gaumeri had the best values. The proposed in vitro protocol showed to be useful for the integral assessment of the nutraceutical potential of different plant species as it included the nutritional value and the AH activity against eggs and L3 in the selected plant species