Uso de la amilasa termoestable de Bacillus licheniformis en la digestibilidad in vitro del almidón de sorgo y maíz

Varias enzimas celulolíticas se han usado para incrementar la digestion ruminal de la fibra y mejorar la producción en rumiantes. Sin embargo, se ha dado poca atención a las enzimas amilolíticas como un tratamiento a los granos, a pesar de que la productividad del ganado puede mejorar con el uso de mezclas de enzimas externas, incluyendo amilasas y celulasas. Así, se incubó sorgo, sorgo rolado con vapor y maíz (500 mg de grano), con fluido ruminal para estudiar el efecto de la adición de alfa-amilasa de Bacillus licheniformis (400 mL) en la digestibilidad in vitro del almidón a las 12 h de fermentación. La incubación (bloque) fue repetida tres veces y los resultados se analizaron bajo un diseño de Bloques Completos al Azar Generalizado, utilizando la interacción bloque por tratamiento para estimar el error experimental. No se detectó interacción entre tipo de grano y enzima. La adición de la enzima termoestable incrementó (p<0.0001) la digestión in vitro del almidón (59.9 vs. 38.5%). La digestión in vitro promedio del almidón (p<0.0001) fue más baja en el sorgo (30.42%), intermedia en el sorgo rolado con vapor (50.72%), y más alta en el maíz (66.48%). La adición de la amilasa termoestable de Bacillus licheniformis incrementó la digestión in vitro del almidón del sorgo y maíz; por lo tanto, esta enzima podría mejorar la digestión in vivo del almidón y la eficiencia alimenticia de dietas basadas en granos con tasas bajas e intermedias de fermentación

Nesting Of Montezuma Quail In Mexico

Although Mexico has the greatest diversity of quail of any New World country, basic information on the ecology and life history of Mexican quails remains unknown. Our objective was to describe nest characteristics of the Montezuma quail (Cyrtonyx montezumae montezumae) in central Mexico. We searched for Montezuma quail nests within 8 counties in the state of México, Mexico during May–September 2003. We conducted nest searches along 66 transects (3–5 km × 40 m) distributed across 17 study sites. We recorded vegetation community, elevation, and nesting substrate for each nest. We measured nest characteristics: height, depth, nest entrance diameter, and orientation. If eggs were found, we recorded clutch size and egg mass, texture, color, and shape. We observed 324 quail and located 6 nests along a 254-km route. Nests were located at elevations ranging from 2,568–2,692 m above sea level. Mean (± standard deviation) nest height and depth were 122.2 ± 7.7 mm and 195 ± 61.8 mm, respectively. Nest entrance orientation for 5 of 6 nests was toward a southerly direction. Mean nest egg mass was 9.9 ± 0.1 g. Our study provides basic and descriptive information on a poorly known quail species in Mexico

In situ degradability of soyabean meal treated with Acacia saligna and Atriplex halimus extracts in sheep

The effects of Acacia saligna (AC) and Atriplex halimus (AT) extracts were evaluated on ruminal soyabean meal (SBM) degradability using the nylon bag technique. Samples of SBM were treated with 0, 4, or 8 g of AC or AT extracts per 100 g SBM. Bags were incubated in two cannulated sheep for 2, 4, 6, 8, 12, 24, and 48 h. The chemical constituents (CCs) of extracts was determined using GC-MS. Rate and potential degradability of dry matter (DM) were decreased (P=0.015) to a greater extent than N degradability (P=0.145) with AC and AT doses. DM and N degradation were decreased (P<0.05) by 15% and 29%; 24% and 47% with AC, and 21% and 29%; 23% and 37% with AT at 4% and 8% for DM and N, respectively. The data suggest the possibility of using these extracts as feed additives to reduce ruminal degradability of SBM in ruminant diets

Evaluation of psychomotor skills acquired for surgery by veterinary students using biological simulators

This study aimed to evaluate the acquisition of psychomotor skills using biological simulators in surgical practices by thirdyear students of Veterinary Medicine at the Autonomous Metropolitan University, Mexico City. The Gibson Spiral Test was applied pre- and post-practice to 171 students (92 women, 79 men) between 18 and 38 years old. The techniques practiced were: ligature, synthetic skin, enterotomy, enterectomy, gastrostomy, cystotomy, endotracheal tube placement, permanent intravenous catheter. Students were classified as fast-accurate (FA), fast- inaccurate (FI), slow-accurate (SA), and slow-inaccurate (SI). The test duration decreased by 7.91s (P0.10). There were differences among the fast (F) and slow (S) students pre-practice (P0.10). Comparing practice time difference (P=0.007) between slow and fast in the pre-practice, men performed more quickly in pre-practice and after practice (P<0.0001), with no differences in mean number of errors pre- (P=0.662) and post-practice (P=0.962). We conclude that students showed progress in acquiring motor skills, by increasing their speed and reducing errors, thus increasing the number of fast and accurate students. Men outperformed women

Genetic variability and structure of an isolated population of Ambystoma altamirani, a mole salamander that lives in the mountains of one of the largest urban areas in the world

Amphibians are globally threatened by habitat loss and fragmentation; species within the order Ambystoma are not the exception, as there are 18 species of mole salamanders in México, of which 16 are endemic and all species are under some national or international status of protection. The mole salamander, Ambystoma altamirani is a microendemic species, which is distributed in central México, within the trans-Mexican volcanic belt, and is one of the most threatened species due to habitat destruction and the introduction of exotic species. Nine microsatellite markers were used to determine the genetic structure, genetic variability, effective population size, presence of bottlenecks and inbreeding coefficient of one population of A. altamirani to generate information which might help to protect and conserve this threatened species. We found two genetic subpopulations with significant level of genetic structure (FST = 0.005) and high levels of genetic variability (Ho = 0.883; He = 0.621); we also found a small population size (Ne = 8.8), the presence of historical (M = 0.486) and recent bottlenecks under IAM and TPM models, with a low, but significant coefficient of inbreeding (FIS = −0.451). This information will help us to raise conservation strategies of this microendemic mole salamander species

In Vitro Gas, Methane, and Carbon Dioxide Productions of High Fibrous Diet Incubated With Fecal Inocula From Horses in Response to the Supplementation With Different Live Yeast Additives

Yeast supplementation of horse diets can influence nutrient digestibility and microbiota dynamics in the horse hindgut. In some in vitro [6] and in vivo [4] studies, yeast addition to the diets improved digestion of low-quality forages. It has been shown that yeast supplementation can alter the microbial environment by increasing the total number of hindgut microorganisms [7]. As a result, feed digestion in the hindgut can be enhanced, especially that of the fiber fraction, most likely due to increased numbers of cellulolytic bacteria in the hindgut [8]. In contrast, other studies have reported no effect of yeast addition to equine diets on nutrient digestibility in vitro [7] or in vivo [9].In a randomized block design experiment, the effect of fecal inocula from horses supplemented with live yeast (Saccharomyces cerevisiae) in diets containing 50% oat straw on in vitro total gas (gas production [GP]), methane (CH4), and carbon dioxide (CO2) productions as indicators of hindgut activity was assessed. Three commercial products of S. cerevisiae were tested (1) Biocell F53 (YST53), (2) Procreatin 7 (YST07), and (3) Biosaf SC47 (YST047). For the incubations, each product was added at 0 (control without yeast addition), 2, or 4 mg/g dry matter (DM). Fecal inocula for incubations with each treatment was obtained from Quarter Horse mares fed the same yeast additives for 15 days, resulting in four different fecal inocula (FI53, FI07, FI47, and FI00). The fecal content mixed with the culture media were used to inoculate three identical runs of incubation in bottles containing 1-g DM of substrate (a mixture of concentrate and oat straw [1:1 DM]). The GP, CH4, and CO2 productions were measured at 2, 4, 6, 8, 10, 12, 24, and 48 hours postincubation. Addition of additives YST53 and YST07 at 2 mg/g DM resulted in higher asymptotic GP (linear effect, P ¼.021) and GP during the first 12 hours of incubation (linear effect, P <.05) compared with control without yeast addition, with the highest value being for the dose 2 mg/g DM with the fecal inoculum FI53. The additive YST47 at all doses with fecal inoculum FI47 had lower GP (linear effect, P < .05) at different incubation hours compared with control. The additive YST53 increased GP, CH4, and fermentation kinetics at the dose 2 mg/g DM with decreasing CH4 production by 78% at 4 mg/g DM at 24 hours of incubation. Addition of YST53 at 2 and 4 mg/g DM with fecal inoculum FI53 enhanced fermentation kinetics (P < .05) compared with control and other additives at different doses. It can be concluded that the yeast additive Biocell F53 was the most effective at doses of 2 and 4 mg/g DM compared with other Saccharomyces strains to attain a more favorable hindgut fermentation to digest fibrous roughages by horses

Carcass analysis of four quails species in Mexico State

The human diet consists of a great diversity of foods in where the most common source of protein comes from animals; mainly from fattening species of pigs, beef, chickens, and sheep due to intensive farming high fat content. The current study was aimed to evaluate the meat analysis of four species of wild quail breasts: Common quail, Banded quail, scaled or Squamous quail and Montezuma quail. Quails were collected from March to June, in the State of Mexico. The findings showed that of the studied species, the meat of Moctezuma had the greatest amount of protein (26.99%DM); however, the lowest fat content (1.25%DM) was with Squamos. Up to the time of this investigation, no data existed on the nutritional qualities of meat coming from these wild species in the State of Mexico. As we now know, this meat has better attributes, compared even to rabbit meat and to the meat of other domestic species that are consumed on a daily basis. It was concluded that the carcasses protein and dry matter contents were similar with all studied species where fat content of the Callipepla squamata had the highest value

Effect of season on chemical composition and in situ degradability in cows and in adapted and unadapted goats of three Mexican browse species

Browse foliages from Lysiloma acapulcencis, Quercus laeta and Pithecellobium dulce, native to the subtropical region of southern México, were harvested during the dry season (DS) and rainy season (RS) to determine in situ degradability using ruminal inoculum from fistulated cows as well as goats previously adapted (AG) or not adapted (UG) to browse species fed in their daily diet. Browse leaf samples were incubated in the rumen of each group for 48 h. The crude protein (CP) content of browse was considerably higher in RS (P<0.001). P. dulce had the lowest neutral detergent fiber (NDFom) and acid detergent fiber (ADFom) in the two seasons; L. acapulcencis had the highest values and Q. laeta values were intermediate, with an overall increase in fiber fractions in DS browse foliage (P<0.001). The lowest in situ degradability values were in L. acapulcencis and Q. laeta had intermediate values during both seasons. Season of harvest (RS or DS), and ruminal inoculum (cows, UG, and AG) affected (P<0.001) dry matter degradability (DMD), crude protein degradability (CPD) and fiber fractions of browse. Nutrient degradabilities in all species were higher (P<0.001) in DS than RS. Goats previously exposed to these browse species (AG) had higher (P<0.001) in situ degradability of the browse species than cows or goats in UG fed diets without browse. Overall, goats had higher (P<0.001) nutrient in situ degradability than cows. Our results suggest higher potential of these browse species as forages for ruminants during the dry period in semi-arid regions, but goats previously exposed to diets supplemented with the browse species had a better ability to degrade them than cows or goats in UG. P. dulce has the highest potential as a feed protein source in small ruminants during the dry period

Effect of a Fibrolytic Enzymatic Extract from Cellulomonas flavigena on In Vitro Degradation and In Vivo Digestibility and Productive Performance of Lambs

An enzymatic extract from Cellulomonas flavigena was evaluated at 0, 2.5, 7.5, 12.5 mL/kg DM of total mixed ration (TMR) on the in vitro degradation of DM, NDF and ADF and in vivo at 0, 5.0 and 7.5 mL of extract per kg DM of TMR to determine the digestibility and productive performance of lambs fed a TMR made up of 60% forage. Twenty four Pelibuey-Kathadin lambs were used in the trial. The in vitro degradation of ADF showed a linear (P<0.05) response from 6 to 72 h. There was no effect on DM intake, daily gain or feed conversion. The enzymatic dose tended to linearly decrease the apparent digestibility of DM (P=0.06), NDF (P=0.10) and ADF (P=0.06). The N-NH3 concentration showed a linear decrease (P=0.002) and total VFA concentration was linearly (P<0.001) increased. The incorporation of extract of Cellulomonas flavigena in the diet increased in vitro degradation of cellulose in terms of ADF but did not increase the digestion or productive performance of lambs

Enzimas amilolíticas exógenas en la alimentación de rumiantes

Recientemente, las enzimas exógenas se están usando para mejorar la degradabilidad ruminal de la fibra dietaria y del almidón presente en los alimentos utilizados en la alimentación de rumiantes. Estas enzimas representan una alternativa para incrementar la productividad y reducir los costos por alimentación, ya que se podría reducir el uso de granos, debido al mayor aporte de energía que realizarían los sustratos fibrosos. La actividad amilolítica de los microorganismos ruminales se da principalmente por la acción de enzimas extracelulares, las que en cocultivo han manifestado su máximo potencial para digerir el almidón. Diversas investigaciones han demostrado que la digestión ruminal del almidón es incompleta y más para aquellos granos de tasas de digestión lenta como el sorgo. Esta digestión incompleta es el resultado de la interacción entre las características del almidón (tipo de grano), condiciones fisicoquímicas del rumen y las enzimas amilolíticas microbiales. Las enzimas exógenas, producto de la biotecnología, actúan en intervalos amplios de pH (4 - 9) y temperatura (30 - 90 C), las cuales podrían actuar sinérgicamente con las bacterias microbiales del rumen e incrementar la degradabilidad ruminal del almidón. Los avances en el uso de enzimas amilolíticas exógenas para incrementar el aprovechamiento del valor energético de los granos utilizados en la elaboración de alimentos para rumiantes, es una excelente alternativa para mejorar la producción animal