ABSTRACT Collared peccaries (Pecari tajacu) roam the forests of natural areas in America. Wild collared peccary appears to be a carrier for bacteria associated with infections in humans and animals, however, the presence of diarrheagenic E. coli (DEC) pathotypes has not been studied in the captive collared peccary. This study aimed to study the prevalence of DEC, the susceptibility to antibiotics, and the frequency of β-lactamase genes (ESBL) in captive collared peccary faeces. DEC strains were identified in 44.4% (N=56) of the E. coli-carrying peccaries under study. The following DEC strains were identified: ETEC (35.7%), EAEC (28.6%), STEC (21.4%) and EPEC (14.3%). Most of the identified DEC strains belonged to clade I (58.9%). The genetic marker rfbO157 was not found in any STEC strain. Of the DEC strains, 67.9% (N=38) were considered multidrug resistant and were not susceptible to ampicillin (75%) nor to carbenicillin (51.8%). The combination of the genes blaTEM + blaCTX and blaTEM + blaSHV (6 strains respectively) was the most frequent among the DEC strains. It is concluded that captive collared peccaries are carriers of DEC strains that carry β-lactamase blaTEM, blaCTX and blaSHV genes and are not susceptible to ampicillin. Given the current efforts of the Wildlife Management Units (WMU) to reintroduce the collared peccary into natural areas, these captive collared peccaries act as carriers of diarrheagenic E. coli strains and therefore a potential source of gastrointestinal disease in humans and animals.

Abstract This study evaluated chemical composition, in situ dry matter degradability (DMD), energy utilization, and amino acid profile of the sandbox seed meal (SSM) obtained from ground seeds of Hura crepitans trees. Two cannulated male Blackbelly sheep (initial weight of 40 kg) were fed a balanced feed ad libitum for 21 days; rumen samples of animals were collected for seven days using the nylon bag technique for degradability. The results were interpreted in reference to incubation times from 0 to 72 h, evaluating degradation kinetics with an exponential model. The SSM showed crude protein and dry matter contents of 251.1 and 931.7 g/kg, respectively. The highest DMD value was recorded from 0 to 3 h with a change rate of 41%, and the energy contained in SSM had a gradual ruminal disappearance with a maximum value of energy utilization of 14.6% after 72 h post-incubation. The most representative amino acids of SSM were glutamic (16.9%), arginine (13.0%), and aspartic (9.7%) acids. The results suggest that SSM has adequate nutritional quality and ruminal DMD for ovine feeding systems.

Abstract Propolis and oregano oil are natural substances used in various food industry applications. An evaluation was done of the effects of oregano oil (A) and propolis (P) on production parameters, leukocytes, blood chemistry and meat antioxidant stability in broilers. Animals (n= 480) were randomly allocated to four treatments with four replicates of 30 animals each. Four additive levels (mg/k feed) were tested: C (control)= 0; P= 100 mg propolis; A= 100 mg oregano oil; and AP= 50 mg P + 50 mg A. At 42 d breast meat lipid oxidative stability was estimated based on malondialdehyde (MDA) content. The oregano oil contained 43.47% thymol and 29.16 % carvacrol, while the propolis contained 5.6 mg flavonoids, 840 µg phenols and 138 µg Trolox® equivalents (antioxidant stability) per gram. Feed intake, weight gain, feed conversion and mortality were unaffected by the dietary additives. At 3 wk, blood eosinophil levels increased in treatment AP (P≤0.05), and at 6 wk triglycerides had increased in treatment A (P≤0.05). Meat lipid oxidative stability decreased in the AP treatment (P≤0.05). Neither oregano oil nor propolis improved production parameters, although they can stimulate immune response. When added to low-fat broiler diets they can increase blood triglycerides and in combination they compromise breast meat lipid oxidative stability.

Resumen Se estudió el efecto de propóleo (P) y aceite de orégano (A) sobre parámetros productivos, leucocitos, compuestos químicos en sangre y la estabilidad oxidativa de la carne de pechuga. Los pollos (n= 480) fueron distribuidos en cuatro tratamientos con cuatro repeticiones de 30 pollos. Se probaron cuatro niveles de aditivos: TES= 0, P= 100 mg de propóleos, A= 100 mg de aceite de orégano y AP= 50 mg de A + 50 mg de P por kilo de alimento. A los 42 días dos aves por repetición se sacrificaron y su pechuga se colectó para determinar su estabilidad oxidativa midiendo el malondialdehído (MDA). El aceite de orégano contenía 43.47 % de timol y 29.16 % de carvacrol, los propóleos 5.6 mg de flavonoides, 840 µg de fenoles y 138 µg equivalentes de Trolox® por gramo de propóleo. El consumo de alimento, ganancia de peso, conversión alimenticia y mortalidad no aumentaron por efecto de los aditivos. En aves de tres semanas incrementaron los eosinófilos con AP (P≤0.05), en aves de seis semanas aumentaron los triglicéridos con A (P≤0.05) y la oxidación de las grasas fue mayor en carne de aves que recibieron AP (P≤0.05). En conclusión, el aceite de orégano y propóleos no aumentaron los parámetros productivos, pueden estimular la respuesta inmune, en dietas bajas en grasa aumentan los triglicéridos en sangre y su combinación afecta la estabilidad oxidativa de la carne de pechuga.

Abstract Nowadays there are currently restrictions on the usage of synthetic additives in chicken production in several countries; an alternative is to use natural substances that could have different functions and effects on broiler. The objective of the research was to evaluate three levels of propolis (0, 100 and 200 mg per kg-1 of feed) in poultry for 42 days. Propolis at 200 mg kg-1 increased feed conversion (FC) in three-week old birds (P≤0.05), but at 100 mg kg-1 decreased weight gain (WG) in six-week old birds (P≤0.05). Propolis at both concentrations increased the amount of lymphocytes, heterophils and eosinophils in three-week old birds (P≤0.05) and monocytes in six-week old birds (P≤0.05). At 100 and 200 mg kg-1 of food the urea decreased in three-week old birds (P≤0.05), while at 200 mg kg-1 the cholesterol and triglyceride levels increased in six-week old birds (P≤0.05). In addition, at 200 mg propolis of kg-1 the oxidation of lipids in breast meat decreased (P≤0.05). The propolis added to the poultry feed did not increase the productive yield but the malondialdehyde present in breast meat decreased.

Resumen En la actualidad hay restricciones para usar aditivos sintéticos en la producción de pollo en varios países, una alternativa es usar sustancias naturales que pudieran tener diferentes funciones y efectos sobre las aves. El objetivo de la investigación fue evaluar tres niveles 0, 100 y 200 mg de propóleos por kg-1 de alimento en aves de engorda durante 42 días. El propóleo a 200 mg kg-1 aumentó la conversión alimenticia (CA) en aves de tres semanas de edad (P≤0.05), pero a 100 mg kg-1 disminuyó la ganancia de peso (GP) en aves de seis semanas (P≤0.05). El propóleo en ambas concentraciones aumentó la cantidad de linfocitos, heterófilos y eosonófilos en aves de tres semanas (P≤0.05) y los monocitos en aves de seis semanas (P≤0.05). A 100 y 200 mg de propóleos por kg-1 de alimento disminuyó la urea en aves de tres semanas (P≤0.05), mientras que a 200 mg por kg-1 incrementó los niveles de colesterol y triglicéridos en aves de seis semanas (P≤0.05). Además, a 200 mg de propóleos por kg-1 la oxidación de los lípidos en la carne de la pechuga disminuyó (P≤0.05). El propóleo adicionado al alimento de las aves no incrementó el rendimiento productivo pero el malondialdehído presente en carne de la pechuga disminuyó.

Bovine leptospirosis causes high economic losses in cattle mainly due to reproductive failure, as well as representing public health risk. Since the last century, antibody titers against several Leptospira serovars have been detected by the microscopic agglutination test (MAT) in Mexico. With the exception of very few cases, the presence of serovars causing leptospirosis in cattle and other animal species has not been demonstrated by isolation in Mexico, and in such cases characterization had to be done abroad by complex and slow immunological approaches, by comparison with a number of reference strains. The present study was conducted to perform the molecular characterization of Leptospira isolates by multiple locus sequencing typing (MLST). A hundred and ninety seven sera and kidneys samples were collected immediately after slaughter, from grazing cattle coming from the south-eastern states of Mexico. Anti-Leptospira antibodies were detected by the MAT and kidneys were inoculated into EMJH and Fletcher's specific medium. A seropositivity of 60.4% (119 out of 197), with titers from 1:100 up to 1:3 200 was detected. Four isolates (2.03%), referred as CAL4, CAL6, CAL7 and MOCA45, were characterized by serology, ribotyping and MLST as L. kirschneri serovar Grippotyphosa; L. interrogans serovar Hardjo; L. santarosai serovar Mini and L. santarosai serovar Tarassovi, respectively. With the exception of serovar Hardjo, the three other isolates belong to serovars and species not previously isolated in Mexico. These findings make it necessary to evaluate the potential distribution of such serovars among cattle and their role on animal production and public health.

La leptospirosis bovina causa grandes pérdidas económicas a la ganadería por problemas reproductivos y también es un riesgo de salud pública. En México, desde el siglo pasado se ha registrado la presencia de anticuerpos contra serovariedades de Leptospira por la técnica de aglutinación microscópica (AM), en bovinos y otras especies animales. En muy pocos casos, la enfermedad fue demostrada por el aislamiento de Leptospira, y en tales casos, su caracterización se basó en métodos inmunológicos lentos que requirieron la comparación con cepas de referencia y que fueron realizados fuera de México. En el presente trabajo se realizó la caracterización molecular mediante la secuenciación de locus múltiples (MLST), de aislados de Leptospira obtenidos de riñones de bovinos recolectados en rastro, procedentes de las zonas Golfo y sur de México. Se obtuvieron muestras de suero y riñones de 197 bovinos para realizar la AM, y el cultivo en medios específicos EMJH y Fletcher. Se detectó una seropositividad del 60.4% (119 de 197), con títulos desde 1:100 hasta 1:3,200 y se obtuvieron cuatro aislados de Leptospira (2.03%), denominados CAL4, CAL6, CAL7 y MOCA45. Los aislados fueron caracterizados por serología, ribotipificación y MLST, como L. kirschneri serovariedad Grippotyphposa; L. interrogans serovariedad Hardjo; L. santarosai serovariedad Mini y L. santarosai serovariedad Tarassovi, respectivamente. A excepción de la serovariedad Hardjo, los aislados pertenecen a especies y serovariedades no aisladas anteriormente en la República Mexicana, esto sugiere la necesidad de evaluar su diseminación entre bovinos y su potencial efecto en la producción animal y en la salud pública.