Effects of endozoochory and diploendozoochory by captive wild mammals on Juniperus deppeana seeds.

Carnivorous mammals disperse seeds through endozoochory and diploendozoochory. The former consists of ingestion of the fruit, passage through the digestive tract, and expulsion of the seeds, a process that allows scarification and dispersal of the seeds over long or short distances. The latter is typical of predators that expel seeds that were contained in the prey and the effects of which may differ from those of endozoochory with respect to the retention time of the seeds in the tracts, as well as their scarification and viability. The objective of this study was to conduct an experimental evaluation comparing the capacity of each mammal species in terms of the dispersal of Juniperus deppeana seeds and, at the same time, to compare this capacity through the two dispersal systems: endozoochory and diploendozoochory. We measured dispersal capacity using indices of recovery, viability, changes in testas, and retention time of seeds in the digestive tract. Juniperus deppeana fruits were collected in the Sierra Fría Protected Natural Area in Aguascalientes, Mexico, and were administered in the diet of captive mammals: gray fox (Urocyon cinereoargenteus), coati (Nasua narica) and domestic rabbits (Oryctolagus cuniculus). These three mammals represented the endozoochoric dispersers. For the diploendozoochoric treatment, seeds excreted by rabbits were incorporated into the diets of captive mammals: bobcat (Lynx rufus) and cougar (Puma concolor), in a local zoo. Seeds present in the scats were then collected, and recovery rates and retention times were estimated. Viability was estimated by X-ray optical densitometry and testa thicknesses were measured and surfaces checked using scanning electron microscopy. The results showed a recovery of seeds greater than 70% in all the animals. The retention time was <24 h in the endozoochory but longer at 24-96 h in the diploendozoochory (p < .05). Seed viability (x¯ ± SD) was decreased in rabbits (74.0 ± 11.5%), compared to fruits obtained directly from the canopy (89.7 ± 2.0%), while gray fox, coati, bobcat, and cougar did not affect seed viability (p < .05). An increase in the thickness of the testas was also observed in seeds excreted from all mammals (p < .05). Through evaluation, our results suggest that mammalian endozoochory and diploendozoochory contribute to the dispersal of J. deppeana by maintaining viable seeds with adaptive characteristics in the testa to promote forest regeneration and restoration. In particular, feline predators can provide an ecosystem service through scarification and seed dispersal.

Presence of the toxigenic fungi Aspergillus spp. and Fusarium spp. in Musca domestica L. (Diptera: Muscidae) collected from dairy farms.

The objective of the study was to identify the presence of toxigenic fungi Aspergillus spp. and Fusarium spp. in domestic flies collected from dairy farms. We selected 10 dairy farms distributed in the central valley of the state of Aguascalientes, México. The flies were trapped using entomological traps with an olfactory attractant in 7 sites of the farm (silo-cutting surface, feed store, milking parlor, 3 feeders, and the rearing room). The fungi were cultivated in Sabouraud agar through direct sowing by serial dilutions to obtain the isolates, and a taxonomical identification was carried out under the microscope. The aflatoxins and zearalenone production capacity of the pure isolates were quantified using the ELISA test. The flies were present in all of the capture sites (45.3 flies, 567 mg, trap per day). We obtained 50 isolates of Aspergillus spp. genus, 12 of which produced aflatoxins (327 ± 143 µg/kg), whereas from 56 of the Fusarium spp. isolates, 10 produced large quantities of zearalenone (3,132 ± 665 µg/kg). These results suggest that the presence of domestic flies on dairy farms can constitute a source of dissemination for toxigenic fungi that can eventually contaminate grains and forage that are part of the daily cattle diet.

Study of ex-ovo embryonic development of Gallus gallus domesticus / Estudio inicial del desarrollo embrionario ex-ovo de Gallus gallus domesticus

SUMMARY: The domestic chicken is a species of bird that has been extensively studied in regard to its biology and as a model organism for science. The reproduction of the species is by the laying of fertilized eggs, which in a period of 21 days will develop a chick inside. Several methods have been described to develop embryos ex-ovo, allowing the observation and manipulation of the organism. This work has the propose to standardize a method that allows the development of the embryos inside the artificial incubation system, which has a low cost and is easy to make. In this work, 100 chicken eggs were used to study the effects of humidity, mineral supplementation, and the preincubation time of the egg on the incubation ex-ovo of the embryos. Embryo development was documented through the different days. Pulverized eggshell was selected as an optimal source to provide calcium, magnesium, phosphorus, and other minerals to the developing embryo. By providing 900-1200 mg of pulverized eggshell, 40 mL of the 0.001 % solution of benzalkonium chloride, and a preincubation time of approximately 56 h, the embryos were able to develop until 19 days, and even though they did not reach hatching, the incubation conditions that allowed the survival and development of embryos until late stages were achieved. Thus, due to the conditions established for calcium, humidity and preincubation time, in the present work, the chicks reached 19 days of development.

El pollo doméstico es una especie de ave que ha sido ampliamente estudiada en cuanto a su biología y como organismo modelo para la ciencia. La reproducción de la especie es por la puesta de huevos fecundados, que en un período de 21 días desarrollarán un polluelo en su interior. Se han descrito varios métodos para desarrollar embriones ex-ovo, permitiendo la observación y manipulación del organismo. Este trabajo tuvo como objetivo estandarizar un método que permita el desarrollo de los embriones dentro del sistema de incubación artificial, el cual tiene un bajo costo y es fácil de realizar. En este trabajo se utilizaron 100 huevos de gallina para estudiar los efectos de la humedad, la suplementación mineral y el tiempo de preincubación del huevo sobre la incubación ex-ovo de los embriones. El desarrollo embrionario se documentó a través de los diferentes días. Se seleccionó la cáscara de huevo pulverizada como una fuente óptima para proporcionar calcio, magnesio, fósforo y otros minerales al embrión en desarrollo. Al suministrar 900-1200 mg de cáscara de huevo pulverizada, 40 mL de la solución de cloruro de benzalconio al 0.001 % y un tiempo de preincubación de aproximadamente 56 h, los embriones lograron desarrollarse hasta los 19 días, y aunque no llegaron a eclosionar, los embriones lograron desarrollarse hasta los 19 días. Se lograron condiciones de incubación que permitieron la supervivencia y desarrollo de los embriones hasta etapas tardías. Así, debido a las condiciones establecidas de calcio, humedad y tiempo de preincubación, en el presente trabajo los pollitos alcanzaron los 19 días de desarrollo.

First report of Fusarium equiseti causing root and crown rot in tomato in Mexico.

Tomato (Solanum lycopersicum L.) is one of the most important crops in Mexico due to its economic and nutritional value. Among the main diseases in tomato production is Fusarium wilt, which can cause 60% production losses (Ascencio et al, 2008). Mixed infections of Fusarium species or other fungi genera, would increase disease severity. During April to May of 2021, tomato plants with more than 60 days old, were collected from the main production areas of Aguascalientes (22°03'46.5"N 102°05'17.4"W and 22°04'53.64"N 101°58'55.81"W) and Zacatecas (23°05'59.2"N 102°41'07.3"W and 22°16'52.1"N 102°00'11.8"W) Mexico states. Plants showed main root rot, vascular bundles necrosis with corky appearance, stem crown rot, and ascending yellowing. The main root and stem crown were cut in 0.25 cm2 pieces and disinfested in 2% NaClO for one minute, rinsed with distilled water two times, placed on acidified potato dextrose agar (PDA) medium, and incubated at 25 ± 2°C for 7 days. Characteristic Fusarium growths were purified by hyphal tip on PDA, subsequently pure strains were obtained by single-spore isolation method. Several fungi colonies were obtained, but we focused on the colonies that showed abundant aerial mycelium of white color and irregular growth, which turned yellowish to golden and brown color as it ages. Carnation leaf agar (CLA) medium were used for conidia and sporodochium development. Chains of terminal, intercalary and agglomerated chlamydospores with thick, rough brown walls of 18.9 (7.46) µm in diameter (n=120) were observed in the mycelium. Macroconidia with 5 to 7 septa were 30 to 75 (28.32) µm in long and 1.2 to 4.8 (3.2) µm in wide (n=72). Basal cell developed in foot-shape, apical cell was elongated and slightly curved, and some macroconidia had swollen midd-cell. Sporodochium was orange to brown in color and microconidia were absent (Figure 1). Two representative strains from each state, LCA-3.1 and EMA-1 from Aguascalientes and ECZ-4 and LRZ-6 from Zacatecas, were selected for DNA amplification of ITS, TEF-1α and RPB2 regions, with universal primers ITS1/ITS4, EF1/EF2 and 2-5F2/7cR (White et al.1990; O'Donnell et al. 1998, 2013). PCR products were sequenced by Psomagen, Inc. (USA). The sequences obtained showed 100% of similarity among themselves and within species of the Fusarium incarnatum-equiseti species complex (FIESC) with nucleotide NCBI accessions NR_121457 (Type material) for ITS and MW362069 for TEF-1α; and 99.28% with MN170399 for RPB2 in FUSARIOID-ID database. According to morphological (Leslie and Summerell, 2006) and molecular characteristics, isolates were identified as Fusarium equiseti (FIESC 14). The LCA-3.1 sequences were selected to be deposited in GenBank with accession numbers OM812801 (ITS), OM937108 (TEF-1α) and ON653596 (RPB2). Pathogenicity tests were performed twice, under greenhouse conditions in tomato seedlings of cv. Rio Grande. Five tomato seedlings were inoculated by root immersion method (Lopez et al, 2018) in a 1x106 spores/mL solution for 8 min, and transplanted to 1L pots with sterile peat. Five controls plants were immersed in sterile water. At 14 days after inoculation, a general plant decline and slower growth compared to the control plants were observed. Subsequently, plants showed root rot, vascular necrosis, and a brown ring in stem crown. Controls were symptomless. The fungi were re-isolated from symptomatic plants and were morphologically similar to the inoculated strains. Patel et al. (2017) described the pathogenic and toxic effects of F. equiseti on tomato, causing low seed germination, and low root and shoot growth. This is the first report of F. equiseti causing root and stem rot in tomato plants in Mexico.

Assessment of the Potential of a Native Non-Aflatoxigenic Aspergillus flavus Isolate to Reduce Aflatoxin Contamination in Dairy Feed.

Aspergillus species can produce aflatoxins (AFs), which can severely affect human and animal health. The objective was to evaluate the efficacy of reducing AF contamination of a non-aflatoxigenic isolate of A. flavus experimentally coinoculated with different aflatoxigenic strains in whole plant (WP), corn silage (CS), immature grains (IG) and in culture media (CM). An L-morphotype of A. flavus (CS1) was obtained from CS in a dairy farm located in the Mexican Highland Plateau; The CS1 failed to amplify the AFs biosynthetic pathway regulatory gene (aflR). Monosporic CS1 isolates were coinoculated in WP, CS, IG and CM, together with A. flavus strains with known aflatoxigenic capacity (originating from Cuautitlán and Tamaulipas, Mexico), and native isolates from concentrate feed (CF1, CF2 and CF3) and CS (CS2, CS3). AF production was evaluated by HPLC and fungal growth rate was measured on culture media. The positive control strains and those isolated from CF produced a large average amount of AFs (15,622 ± 3952 and 12,189 ± 3311 µg/kg), whereas A. flavus strains obtained from CS produced a lower AF concentration (126 ± 25.9 µg/kg). CS1 was efficient (p < 0.01) in decreasing AF concentrations when coinoculated together with CF, CS and aflatoxigenic positive control strains (71.6−88.7, 51.0−51.1 and 63.1−71.5%) on WP, CS, IG and CM substrates (73.9−78.2, 65.1−73.7, 63.8−68.4 and 57.4−67.6%). The results suggest that the non-aflatoxigenic isolate can be an effective tool to reduce AF contamination in feed and to minimize the presence of its metabolites in raw milk and dairy products intended for human nutrition.

Aspergillus flavus and Total Aflatoxins Occurrence in Dairy Feed and Aflatoxin M1 in Bovine Milk in Aguascalientes, Mexico.

Contamination of food chains by toxigenic fungi and aflatoxins is a global problem that causes damage to human health, as well as to crop and livestock production. The objective is to evaluate Aspergillus flavus and total aflatoxins (AFs) occurrence in totally mixed rations (TMRs) for dairy cows and aflatoxin M1 (AFM1) in milk for human consumption. Ninety-nine dairy production units located in Aguascalientes, Mexico, were randomly selected, and samples were collected from TMRs, raw milk, and milk marketed in the city in two consecutive agricultural cycles. AFs were quantified in TMRs and milk by indirect enzyme immunoassay and HPLC; aflatoxigenic and molecular (PCR) capacity of monosporic A. flavus isolates in the feed was characterized. All feed, raw, and pasteurized milk samples showed aflatoxin contamination (26.0 ± 0.4 µg/kg, 32.0 ± 1.0, and 31.3 ± 0.7 ng/L, respectively), and a significant proportion (90.4, 11.3, and 10.3%) exceeded the locally applied maximum permissible limits for feed and milk (20.0 µg/kg and 50 ng/L). Aflatoxin contamination in both TMRs and milk indicated a seasonal influence, with a higher concentration in the autumn-winter cycle when conditions of higher humidity prevail. The results obtained suggest the existence of contamination by aflatoxigenic A. flavus and aflatoxins in the diet formulated for feeding dairy cows and, consequently, in the dairy food chain of this region of the Mexican Highland Plateau.

Effect of age, sex, and body size on the blood biochemistry and physiological constants of dogs from 4 wk. to > 52 wk. of age.

BACKGROUND: Blood biochemistry and reference intervals help to differentiate between healthy and ill dogs as well as to provide information for the prognosis, evaluation, and monitoring; however, these intervals are often obtained from adult animals. It is essential to understand that puppies and adults are physiologically different, which justifies the need to obtain age-specific biochemical reference intervals. The aim of this research was to assess the potential effect of age, sex, body size, and their interaction on routine biochemical analytes and physiological constants (body temperature, heart rate, and respiratory rate). To carry out the research, we selected 197 healthy dogs of both sexes and different body sizes (small, medium and large) classified by age: group I (4-8 wk), group II (9-24 wk), group III (25-52 wk), and group IV (> 52 wk). The biochemical analysis included the measurement of the enzymatic activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), and the concentrations of cholesterol, triglycerides, total proteins, albumin, globulins, glucose, urea, and creatinine. Statistical analyses used analysis of variance (ANOVA) and a general linear model (GLM), which allows the comparison of multiple factors at two or more levels (p < 0.05). RESULTS: The results of this study showed that ALT, total protein, albumin, globulin, urea, creatinine, and body temperature levels were lower in puppies than in adult dogs of group IV (p < 0.05), while the enzymatic activity of ALP, LDH, glucose concentration, and heart rate were higher. Whereas sex, body size and the interaction did not show a significant effect (p > 0.05). CONCLUSIONS: Some biochemical components are influenced by age. For this reason, this manuscript contributes with additional data for the clinical interpretation of blood biochemical results in puppies.

Seed dispersal by carnivores in temperate and tropical dry forests.

The seed dispersal mechanisms and regeneration of various forest ecosystems can benefit from the actions of carnivores via endozoochory. This study was aimed to evaluate the role of carnivores in endozoochory and diploendozoochory, as well as their effect on seed viability, scarification, and germination in two forest ecosystems: temperate and tropical dry forest. We collected carnivore scat in the Protected Natural Area of Sierra Fría in Aguascalientes, Mexico, for 2 years to determine the abundance and richness of seeds dispersed by each carnivore species, through scat analysis. We assessed seed viability through optical densitometry using X-rays, analyzed seed scarification by measuring seed coat thickness using a scanning electron microscope, and evaluated seed germination in an experiment as the percentage of seeds germinated per carnivore disperser, plant species, and forest type. In the temperate forest, four plant species (but mainly Arctostaphylos pungens) were dispersed by four mammal species. The gray fox dispersed the highest average number of seeds per scat (66.8 seeds). Bobcat dispersed seeds through diploendozoochory, which was inferred from rabbit (Sylvilagus floridanus) hair detected in their scats. The tropical dry forest presented higher abundance of seeds and richness of dispersed plant species (four species) than in the temperate forest, and the coati dispersed the highest number of seeds (8,639 seeds). Endozoochory and diploendozoochory did not affect viability in thick-testa seeds (1,480 µm) in temperate forest and thin-testa seeds (281 µm) in tropical dry forest. Endozoochory improved the selective germination of seeds. Nine plant species were dispersed by endozoochory, but only one species (Juniperus sp.) by diploendozoochory. These results suggest that carnivores can perform an important ecological function by dispersing a great abundance of seeds, scarifying these seeds causing the formation of holes and cracks in the testas without affecting viability, and promoting the selective germination of seeds.

Detection of antibodies and risk factors for infection with bovine respiratory syncytial virus and parainfluenza virus 3 in dual-purpose farms in Colima, Mexico.

A cross-sectional study was carried out, from November 2007 to March 2008, to estimate the prevalence of and to determine risk factors associated with bovine syncytial respiratory virus (BRSV) and parainfluenza 3 virus (PIV3) in dual-purpose herds in Colima, México. One hundred and seventy-six sera from 33 herds for PIV3 and 232 sera from 44 herds for BRSV were used. Sera were analyzed by indirect ELISA for the detection of antibodies against BRSV and PIV3 in cattle herds to determine the seroprevalence of respiratory diseases. The apparent and true prevalences for PIV3 were 60.8% and 54.4% and for BRSV 52.2% and 50.8%, respectively. The percentage of herds showing at least one positive animal was 78.7% for PIV3, and 93.2% for BRSV. Age (≤ 12, 13-48, and >48 months old) and respiratory signs (no, yes) showed significant association (P < 0.05) with PIV3 and age with BRSV. This study showed that animals were exposed to both viruses and that age was the main risk factor. The need to establish new vaccination plans to effectively protect cattle against those infections in the state of Colima, Mexico is suggested.