Tannins are polyphenolic compounds with some beneficial properties for ruminants as they act as antioxidants, antimicrobials, and anthelmintics, which may improve animal performance. However, the results are variable, depending on the type, source, and dose. The objective of this research was to determine the effect on fattening performance and carcass characteristics of lambs supplemented with condensed tannins (CTs) from Acacia mearnsii extract. Thirty-six, three-month-old Dorset x Hampshire cross lambs of 20.8 ± 3.3 kg live weight were used in a completely randomized design with four treatments (n = 9), namely T1: basal diet, 0.0 g CT/kg DM-1; T2: T1 + 1.75 g CT/kg DM-1; T3: T1 + 3.5 g CT/kg DM-1; and T4: T1 + 5.25 g CT/kg DM-1. The daily weight gain was higher in T2 and T3 than in T1. The weight at slaughter and empty weight at slaughter were higher in T2 than in T1. The hot carcass weight was higher in T3 than in T1, but no different from T2 or T4. The hot carcass yield was higher in T3 than in the other treatments. The meat pH at slaughter and 24 hours postmortem was higher in T4 than in T1 and the meat protein percentage was higher in T3 than in T1. The inclusion of CTs from Acacia mearnsii extract in the diet of fattening lambs increased their daily weight gain, yield, and carcass weight.

The effect of including partially dehulled sunflower seeds in the diet of grazing chickens in meat quality was evaluated. Two hundred and forty, one-day-old, Ross 308 chickens were used, randomly distributed into four treatments with six replicates of 10 birds each. Seventy-two birds were slaughtered at seven weeks of age, 18 per treatment, extracting the Pectoralis major muscle to analyze meat quality. The treatments were completely randomized in a 2x2 factorial arrangement, where type of rearing (confinement or grazing) and diet (base diet or base diet substituting 10% soybean meal for partially dehulled sunflower seeds) were the independent variables. The grazing chickens spent 8 hours a day in a white clover (Trifolium repens) paddock. Including sunflower seeds improved (p<0.05) the color and crude protein (CP) in breast meat (p<0.05), while grazing increased (p<0.05) CP, dry mater (DM), and shear force (SF), and the percentage of breast fat decreased (p<0.05) by up to 50%. Additionally, grazing increased (p<0.05) saturated fatty acids (SFA) and reduced (p<0.05) lipid oxidation by up to 50%. Partially replacing soybean meal with partially dehulled sunflower seeds in the diet of grazing chickens with white clover improves the physicochemical characteristics and nutritional quality of the breast meat; it also decreases lipid oxidation, extending the shelf life of the meat.

Aims:The objective of this study was to evaluate the effect of Distillers Dried Grains with Solubles (DDGS) in diets of finishing lambs on ruminal fermentation, digestibility, in vitro gas emissions, growth performance, carcass characteristics and meat quality.Background: Replacing cereal grains and oilseed meals with dried distillers grains can reduce feeding cost and utilise an abundant waste byproduct of the ethanol industry.Methodology: Thirty native Mexican male lambs of four months old and 24 ± 2. 41 kg BW, were used in the experiment which lasted for 56-days using a complete randomized design (n = 10).Treatments were: 1) Control (0% DDGS); 2) (20% DDGS/DM basis) and 3) (40% DDGS/DM basis).Results: DMI, ADG, final body weight (BW) and carcass characteristics were not different (P > 0.05) among the treatments.However, apparent digestibility (AD) of DM (ADDM), ADNDF, ADADF and in vitro digestibility of DM (IVDDM) after 9, 12 and 24 h of incubation showed a quadratic effect while increasing level of DDGS.Rumen fluid pH was greater and ruminal VFA concentration was lower for 20% DDGS treatment (quadratic effect P = 0.05).The proportion of acetate: propionate and concentration of ammonia nitrogen, were not different (P > 0.05) between treatments.Biogas production was maximal at 40% DDGS (linear effect, P = 0.03) while a quadratic effect on CO 2 (P = 0.016) and CH 4 (P = 0.023) were observed.No differences (P > 0.05) on the physicochemical composition and characteristics of the meat of lambs fed different levels of DDGS were found. Conclusion:The 40% DM inclusion of corn DDGS in diets for growing Mexican native lambs maintains its productive performance without significantly affecting the ruminal fermentation, diet digestibility, carcass characteristics and meat quality.DDGS can partially replace grains, oilseed meals and forage due to its high protein content and energy level.If DDGS is low in cost compared to oilseed meals, it may be included in finishing lamb diets.

Ante-mortem studies of stress in rabbits are few and can potentially impact the haematologic response and physicochemical parameters of muscle meat. The aim of this study was to investigate the induction of stress by transport and simulation at two different times. Two hundred rabbits divided in a similar proportion of male and female were stressed by vehicular transportation and with motion simulation, using a vibration platform. They were divided into five groups: Control (without stress), Stress with Short Transportation (30 min), Stress with Long Transportation (60 min), Stress with Short Vibration Platform (30 min) and Stress with Long Vibration Platform (60 min). Transportation caused a decrease in the haematic potassium in both sexes (<5.2 mmol/L). The glucose and lactate concentrations increased in the transported rabbits (>219 and >61 mg/dl respectively). The differences between sexes showed that the P CO2 in males decreased <8.5 mmHg in stress groups compared to without stress group. Glucose concentration was 61.5 mg/dl for females and 38.0 mg/dl for males (p < .01). We concluded that in rabbits induced stress by transport increased the energetic metabolites in the blood tissue. This increase did not affect the production parameters and the quality of muscle meat.

Milk production in Mexico is deficient and there are diarrhea problems in nursing calves. Lactic acid bacteria (LAB) are found in the digestive tract and show an antagonistic effect against enteric pathogens. Addition of prebiotics such as inulin to diets of calves might control gastrointestinal flora. Therefore, the aim of this research was to evaluate the influence of inulin on in vitro growth performance of Lactobacillus casei (Lc), Lactobacillus salivarius (Ls), and Enterococcus faecium (Ef). In vitro incubations were performed at 37°C, replacing the MRS glucose for inulin. The experimental design was complete randomized and treatments (T) were: T1 = MRS-glucose + Ls; T2 = MRS-glucose + Ef; T3 = MRS-glucose + Lc; T4 = MRS-inulin + Ls; T5 = MRS-inulin + Ef; T6 = MRS-inulin + Lc; T7 = MRS-inulin + Ls + Ef; T8 = MRS-inulin + Ls + Lc; T9 = MRS-inulin + Ef + Lc; and T10 = MRS-inulin + Ls + Ef + Lc. Variables were growth curve, pH, lactic acid production, ammonium, strains resistance to hydrochloric acid and bile salts, and antagonism against Escherichia coli and Salmonella typhimurium. Data were statistically analyzed with PROC GLM of SAS, and Tukey test (P < 0.05) was used to compare treatments means. Analysis of results showed a positive effect of inulin on the growth of strains, higher absorbance readings in MRS-inulin as compared to MRS-glucose (2.35d, 2.28d, 2.30d, 2.83abc, 2.67c, 2.64c, 2.75abc, 2.93a, 2.72bc, and 2.88ab, from T1 to T10, respectively; P < 0.05) and higher bacterial count at the end of the growth curve (10.98d, 10.76d, 11.29d, 13.11c, 13.63b, 13.77a, 12.93c, 12.74c, 12.43c, and 12.92c Log 10 UFC mL−1 from T1 to T10, respectively; P < 0.05), whereas no changes were found for the other variables. We conclude that LAB Ls and Ef fermented inulin with a positive effect on strains growth, without affecting their probiotic potential.

El objetivo del presente estudio fue evaluar la variabilidad disponible en 21 genotipos de Brachiaria humi-dícola en cuanto a la concentración de proteína y producción de materia seca, durante la época seca del año. El estudio se realizó durante los meses de marzo, abril y mayo de los años 2004 y 2005, sin aplicar riego ni fertilizante al suelo. Se realizaron tres cosechas por genotipo en cada año, con un tiempo de rebrote de cada cosecha que varió de 33 a 35 d. El experimento fue establecido bajo un diseño de bloques completos al azar en arreglo de parcelas subdivididas. Los resultados mostraron una importante variabilidad entre los genotipos (p ≤ 0.0001) para la concentración de proteína dentro del año, la cual varió de 101.1 a 119.5 g kg-1 de MS, valores que corresponden a los genotipos 26 160 y 26 413. Los genotipos 26 413 y 16 891 fueron los que presentaron las concentraciones de proteína más elevadas pero, sin ser significativamente superiores (p > 0.05) al genotipo 679 (Humidicola comercial). Además, la concentración de proteína mostró una estabilidad importante al ambiente al no interactuar ni con el año ni con la fecha de corte (p > 0.05).

Suizo Pardo x Cebú, y a pesar de su importancia económica poco se conoce sobre el rendimiento y las características de las canales obtenidas. El objetivo de estudio fue evaluar el rendimiento de la canal y de los compo-nentes no cárnicos de toretes criados en tres sistemas de alimentación en clima cálido húmedo. Se utilizaron 31 toretes: 11 de pastoreo extensivo (PE), 10 de pastoreo + suplemento (PS) y 10 de engorda en corral (EC). Las variables de respuesta fueron peso vivo (PV), peso vacío del cuerpo (PVC), rendimiento de la canal (RC) y de los componentes consumibles y no consumibles, contenido del tracto gastrointestinal (CGI), espesor de grasa dorsal (EGD) y marmoleo. El PV fue similar entre los sistemas de crianza evaluados (419.4, 423.6, 414.4 kg en PE, PS y EC, respectivamente). Los toretes finalizados en EC presentaron mayor EGD (4.2 mm; P < 0.05), mayor porcentaje de PVC (90.9%; P < 0.05) y menor CGI (9.04%; P < 0.05). Las canales no mostraron marmoleo en los tres sistemas de alimentación (P > 0.05). Los animales de EC presentaron los mayores porcentajes de piel, patas y aparato respiratorio (9.5, 2.4 y 1.4%, respectivamente). Se concluye que el sistema de EC mejora el terminado de la canal e incrementa el espesor de la grasa de cobertura. El sistema de alimentación afectó el peso del contenido gastrointestinal y el rendimiento de la canal, pero no modificó el rendimiento de los componentes no cárnicos.

Se evaluaron las respuestas productiva y metabólica de corderos en pastoreo suplementados con dos arbustos forrajeros, Morus alba (M) e Hibiscus rosa-sinensis (T). Se utilizaron 32 corderos criollos (Pelibuey x Dorper o Black Belly) con un peso vivo promedio de 18.33±1.56 k. El tiempo del estudio fue de 90 días. Los animales permanecieron en pastoreo continuo y por las tardes se suplementaron (300 g animal−1 d−1) de acuerdo con los siguientes ocho tratamientos: sólo pastoreo (P), P + concentrado (P + C), P + M de 60 días (P + M60), P + M de 90 días (P + M90), P + M de 120 días (P + M120), P + T de 60 días (P + T60), P + T de 90 días (P + T90) y P + T de 120 días (P + T120). Se midieron el consumo de suplemento (CS), el consumo de forraje (CF), la ganancia diaria de peso (GDP), el pH, y la concentración de N-NH3 y de ácidos grasos volátiles (AGV). Las poblaciones de bacterias totales (BT) y protozoarios (PR) fueron determinadas en muestras de líquido ruminal. Los datos fueron estadísticamente analizados con un diseño completamente al azar y la prueba de Tukey para comparación de medias. P + C y P + T60 mejoraron significativamente (p <0.05) el CS. P registró el CF máximo (p <0.05). Los tratamientos P + C y P + T90 incrementaron la GDP. En contraste, P + M90 originó la mínima GDP.

The objective of this study was to evaluate Pediococcus acidilactici (PA) in vitro to determine production of lactic, acetic, propionic and butyric acids, as well as changes in pH, when added to a culture medium with high proportion of non-structural carbohydrates. The experimental design was completely randomized, the lyophilized culture of PA (T1) was evaluated and compared with a group of bacteria of the rumen fluid (RF). The inocula were added to an anaerobic culture medium with D-(+)-glucose (5 %), plus a high-energy diet; besides the addition of monensin (MO) and lasalocid (LA) to the medium was evaluated. Media were incubated at 38 +/- 0.5 degrees C for 3, 6 and 12 h; after each period it was assessed the concentration of lactic acid, volatile fatty acids (VFA), pH, concentration of total bacteria (TB) and lactic acid bacteria (LAB). The results were analyzed using the GLM procedure and by Wilcoxon rank-sum test for TB and LAB concentrations. Lactic acid production was greater (p <= 0.05) in the media inoculated with PA and RF without ionophores, but pH at 12 h of incubation did not change, although pH was reduced since 3 h in all treatments including those with lower production of lactic acid (p <= 0.05), whereas production of total VFA was similar among treatments. The greatest amount (p <= 0.05) of BT was found in the media without ionophores inoculated with RF, compared to those inoculated with PA; the greatest amount of LAB was found in treatments without ionophores. Under these conditions P. acidilactici had a heterofermentative activity producing similar amounts of lactic, acetic, propionic and butyric acids regarding RF; in addition it was sensitive to the ionophores used.

The sprouted wheat (SW) contains the 6-methoxy-2-benzoxazolinone (6-MBOA), a phenol compound that stimulates reproduction in certain small wild herbivorous mammals. The objective of the present study was to evaluate the effect of short-term supplemental dietary SW on libido, semen and sperm characteristics of rabbit bucks. Five-month old New Zealand White pubertal rabbits (n=18) were randomly allocated to one of two treatments: supplementation or not (control) supplemented with SW. The experimental design was completely random with nine replications, experimental unit was one buck. Semen collection for each male was conducted once a week with two ejaculations during 20 weeks. The SW was given during four consecutive days prior to each semen collection. Analysis of variance was under a mixed model: treatment, ejaculate number and season were fixed and rabbit random effects. There was no effect of treatment (P>0.05) on reaction time, gel presence, volume, pH, sperm motility, sperm number per ml and sperm number per ejaculate. The percentage of normal alive spermatozoa was 13.5% greater in SW-supplemented bucks than in the control and the percentage of abnormal alive spermatozoa was 44.1% greater in the control than in the SW-supplemented bucks. The morphology of dead spermatozoa, integrity of acrosome, number of normal alive motile sperm and semen doses per ejaculate were not influenced (P>0.05) by SW supplementation. The proportion of presence of gel and semen volume in the first ejaculate was greater than the second ejaculate (+140% and +56.4%). However, the semen quality in the latter was greater (P=0.0001) than the former in terms of an increase in motility (+29.7%). Reproductive traits were more desirable (P<0.05) in winter than autumn. Dietary wilted SW as a source of biological 6-MBOA enhanced sperm characteristics in terms of a greater percentage of normal alive and lesser percentage of abnormal alive spermatozoa but did not affect the number of normal motile live sperm and suitable semen doses in rabbit bucks in autumn and winter.

Seventy crossbred ewe lambs, born from Pelibuey (PB) dams mated with five sire breeds: White Dorper×PB (WD×PB), Black Head Dorper×PB (BHD×PB), Ile de France×PB (Ile×PB) Katahdin×PB (KT×PB) and Pelibuey (PB×PB), were used to determine age and weight to puberty, follicular populations during prepubertal development, ovulation rate at first ovulation and function of the first corpus luteum (FCL). Ewe lambs were maintained under grazing conditions and were supplemented with 300ghead−1day−1 of a concentrate with 14% CP and 3.0McalMEkg−1 of DM. From 145days of age, monthly observations were performed by endoscopy to monitor follicular populations and luteal structures. Ovarian follicles were classified according to size into small (≥1 and <3mm), medium (≥3 and ≤4mm) and large (>4mm). Additionally, weekly observations by ultrasonography were performed in four ewes per genotype to assess follicular populations. Luteal function from first ovulation was determined by circulating concentrations of progesterone. Ovulation rate was not affected by genotype (P>0.05). All breed groups had the same pattern of follicular populations, where most of follicles were small, followed by medium and a small proportion of large follicles. Maximum diameter of follicles was similar for all genotypes during prepubertal development (P>0.05), with an average range of 3.9±0.20 to 4.4±0.20mm. The BHD×PB reached puberty at the youngest age of 240.9±13.0days, compared to all other genotypes (P<0.05), 259.1±11.7 for WD×PB, 279.3±9.6 for KT×PB and 289.0±15.3days for PB×PB and 308.6±11.9days for Ile×PB ewe lambs. Ile×PB had greater weight to first ovulation (31.5±1.19kg) as compared to other breed groups (P<0.01). The largest percentage of FCL was for KT×PB ewes (100%) (P<0.05), followed by BHD×PB (88.9%), PB×PB (83.3), WD×PB (78.6%) and Ile×PB (77.8%). There were no differences in ovulation rate attributable to type of lambing from which ewe lambs came from (P>0.05). BHD×PB ewe lambs reached puberty at an earlier age than other in this study. KT×PB ewe lambs had the highest percentage of FCL in their first ovulation. Breed of sire Ile de France increased weight to puberty and decreased FCL at first ovulation. In conclusion, the BHD×PB ewe showed puberty at an earlier age than other genotypes, while the KT×PB had the highest percentage of functional corpus luteum in their first ovulation. Ewe lambs coming from single lambings reach puberty at a heavier weight than those coming from multiple lambings. The ovulation rate in the first ovulation of ewe lambs is not affected by genotype and type of lambing.

The aim of this study was to evaluate the influence of age at first mating on the reproductive perfonnance of Pelibuey ewe lambs. The study consisted of two trials: postweaning growth and reproductive handling. Twenty Pelibuey ewe lambs were used which were fed a complete diet throughout the study. In the first trial, the studied variable was the type of birth (TN). Body weight (PV) and daily weight gain (GDP) were studied during 42 days. The TN did not influence (P > 0.05) PV, GDP and age of the ewe lambs at 28 kg PY. In the second trial, the studied variable was the age of the ewe lamb at 28 kg PV: YOUNG (139 days) vs MATURE (169 days). PV and ewe lambs in estrus (%) were studied. In the MATURE group, a 43% (6/13) of ewe lambs in estrus were detected, whereas in the YOUNG group there were no ewe lambs in estrus (017). It was concluded that the type of birth of the ewe lambs had no effect on the postweaning growth perfonnance nor the starting age for reproductive handling at a detennined body weight. The starting age for reproductive handling of ewe lambs had an important effect on estrus detection, and there was a high ratio of reproductive failure in young ewe lambs.

A high production of crossbreed Brown Swiss x Zebu bullocks exists in the damp tropical regions of Mexico, and in spite of its economic importance, there is little information on the characteristics and yield of the carcasses obtained. The purpose of this study was to evaluate the yield of the carcass and non meat components of the bullocks reared in three feeding systems in a damp tropical climate. Thirty one bovines were used: 11 under extensive grazing (PE), 10 under grazing + a complement (PS) and 10 in a dry feed-lot (EC). Measured variables were live weight (PV), empty body weight (PVC), carcass yield (RC), consumable and non consumable body components yield, gastrointestinal tract content (CGI), dorsal fat thickness (EGD) and marbling. PV was similar in all rearing systems (419.4, 423.6, 414.4 kg for PE, PS and EC, respectively). The bullocks reared in EC were younger (P < 0.05), had more EGD (4.2 mm; P < 0.05), a greater PVC (90.9%; P < 0.05) and a lower CGI (9.04%; P < 0.05). Carcasses did not present marbling (P < 0.05) in the three feeding systems (P > 0.05). The bullocks reared in EC presented the greatest percentages of skin, feet and respiratory tract (9.5, 2.4 and 1.4%, respectively). It can be concluded that producing bullocks in EC improves their carcass characteristics and increases the thickness of dorsal fat. The feeding

The objective of this study was to determine the biological activity of anti-nutritional factors present in nine foliage and five fruit samples from forage-trees of Central Chiapas, Mexico, in 2006. The anti-nutritional factors studied were total poly-phenols and condensed tannins. The experimental design was completely-randomized, and statistics was clone by regression and correlation analyzes. The method used was in vitro gas production in an N-enriched solution, and the addition of Poly-ethylene glycol (PEG-4000). Chemical composition and increase in gas production of samples (over 24 hours and total) were analyzed. Chemical composition varied wirdely among species. PEG raised significantly gas production (p<0.05) in foliage of L. collinsii, G. ulmifolia, A. pennatula and A. milleriana and in fruits of A. milleriuna, G. ulmifolia y L. collinsii. In foliage samples, the increase in gas production was negatively related to high phenols and condensed tannin content of the species (FDN= r= -0.68, p<0.04 and r-0.67, p<0.03 respectively). In fruits, there was not relation between phenol and tannin content and gas production, hut there was an inverse relation with fiber contents (FDN= r -0.97, p<0.06 and FDA= r -0.94, p<0.01). The forage-trees studied contain high levels of anti-nutritional factors, particularly in their foliage and PEG is useful to study their anti-nutritional activity.