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Influence of polyethylene glycol on in vitro gas production profiles and microbial protein synthesis of some shrub species


The aim was to determine effects of addition of polyethylene glycol (PEG) on in vitro gas production and microbial protein synthesis of the shrub species Acacia constricta, Acacia shaffneri, Calliandra eriophylla, Condalia lycioides, Cordia parvifolia, Larrea tridentata and Mimosa biuncifera, which are commonly consumed by grazing small ruminants in semiarid regions of Mexico despite the abundance of tannins in their foliage. Three individual samples (a minimum of 10 plants of each) of each shrub species were collected from different areas and prepared for chemical and secondary metabolite analysis. In vitro evaluations for each sample of each shrub species were completed in three incubation runs in different weeks using calibrated glass syringes in a 7 × 2 factorial design (i.e., 7 shrub species × 2 treatments with or without PEG). In vitro gas production after 24 and 96 h, partitioning factor (PF), metabolizable energy (ME) content, efficiency of microbial protein synthesis (EMPS), and volatile fatty acids (VFA) were determined. A shrub species × PEG interaction (P<0.05) only occurred for some VFA, such as C3, C4, C4i and C5i, concentrations. Relative to control, addition of PEG increased (P<0.05) the concentrations of individual VFA in A. shaffneri, C. lycioides and C. parvifolia. Interactions between shrub and PEG occurred (P<0.001) for all gas production parameters (i.e., b, k, IVGP24, IVGP48). The fractional rate of gas production and IVGP24 h were highest in A. constricta and lowest (P<0.001) in A. shaffneri. L. tridentata had the highest PF and C. lycioides the lowest. A. constricta had the highest ME content. Purine content and EMPS differed (shrubs × PEG; P<0.001) among shrubs. Microbial protein synthesis was highest in M. biuncifera and lowest in C. eriophylla, while total VFA were highest in C. eriophylla. Incorporation of PEG increased (P<0.001) in vitro fermentation parameters and ME content with L. tridentata and C. lycioides being the highest. PEG also promoted reductions in the EMPS and PF values. In vitro fermentation variables such as fractional rate of gas production, VFA concentrations and EMPS support the potential of A. constricta, C. parvifolia and M. biuncifera as protein and energy sources for small ruminants in semiarid regions of North Mexico. Increments in gas production in these shrub species confirmed the affinity of PEG to bind condensed tannins and reduce EMPS.


Shrubs Polyethylene glycol In vitro gas production Microbial efficiency CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

In vitro fermentation and microbial protein synthesis of some browse tree leaves with or without addition of polyethylene glycol

Abdelfattah Zeidan Mohamed Salem Peter Robinson Mounir El Adawy Ayman HASSAN (2006)

To assess the nutritional value of the leaf of four browse trees (Chorisia speciosa, Cassia fistula, Schinus molle, Eucalyptus camaldulensis), that are grown in semi-arid regions of northern Egypt, this study evaluated effects of incorporation of polyethylene glycol (PEG) on their nutritional value. In vitro gas production after 24 h of fermentation (IVGP24), volatile fatty acids (VFA), ammonia concentrations and microbial protein synthesis were determined, and in vitro organic matter digestibility (IVOMD) and metabolizable energy (ME) were estimated. The IVGP24, VFA and ammonia N concentrations varied (P<0.001) among browse species, with the IVGP24 and VFA highest (P<0.001) for C. speciosa, lowest (P<0.001) for E. camaldulensis, and intermediate for C. fistula and S. molle. C. speciosa had the highest (P<0.05) IVOMD, microbial protein synthesis, IVOMD and ME, while these measurements were lowest in E. camaldulensis and intermediate in the other browse leaves. In general, C. speciosa has the highest potential as a ruminant feed, the lowest being E. camaldulensis and S. molle, with C. fistula intermediate. Addition of PEG increased (P<0.001) IVGP24, VFA and ammonia N concentrations, as well as gas production (P<0.05). The highest overall improvement was for C. speciosa, intermediate for E. camaldulensis, and lowest for C. fistula and S. molle. Addition of PEG reduced (P<0.01) the amount and efficiency of microbial protein synthesis, and increased (P<0.001) IVOMD and ME in all leaves. The extent of the benefit of PEG on overall nutritive value varied somewhat by browse, with E. camaldulensis judged to have the largest overall improvement, C. fistula the lowest with C. speciosa and S. molle intermediate. However PEG addition did not change overall nutritive ranking of these browse leaves.


Secondary compounds Gas production Microbial efficiency Digestion Metabolizable energy CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

CYP2D6 gene polymorphisms and predicted phenotypes in eight indigenous groups from northwestern Mexico


Aim: Polymorphisms in CYP2D6 impact the interindividual and interethnic variability of drug efficiency; therefore, we determined the CYP2D6 allele distribution in eight Amerindian groups from northwestern Mexico and compared them with the frequencies in Mexican Mestizos. Materials & methods: A total of 508 Amerindians were studied. Genotyping of CYP2D6 5 and multiplication alleles was performed by long-range PCR, while CYP2D62,3,4,6,10,17,29,35,41 and copy number were evaluated by real-time PCR. Results: The most frequent alleles were CYP2D62 (0.05-0.28), CYP2D64 (0.003-0.21) and multiplications (0.043-0.107). CYP2D65,6, * 10 and41 were not observed in the majority of Amerindians, and CYP2D63,17,35 and29 were not detected. The poor metabolizer genotype (4/5) was lower (0.2%) in Amerindians than in Mestizos (5%); conversely, the ultrarapid metabolizer genotype was higher (12.6%) in indigenous groups than in Mestizos (7%). Conclusion: Our data show a lower frequency of CYP2D6 inactive alleles and a higher frequency of duplication/multiplication of CYP2D6 active alleles in indigenous populations that in Mestizos.

Producción Científica de la Universidad Autónoma de Zacatecas UAZ


BIOLOGÍA Y QUÍMICA drug efficiency Mexican Mestizos CYP2D6