No abstract

The levels of polyamines (PAs) in urine are an important biomarker of physiological and pathological phenomena for humans.Due to its importance, the validation of a PAs determination methodology was validated for (Putrescine (Pu), Cadaverine(Cdv), Spermidine (Spd), Spermine (Spm), Epinephrine (Epf) and Histamine (Hst) in urine by Reversed-phase HighPerformance Liquid Chromatography (RP-HPLC) with pre- column derivatization using dansyl chloride and UV detection at254 nm. To this aim, selectivity, working range and linearity, detection /quantification limit were determined. The precision (asrepeatability and precision under intermediate conditions), accuracy (measured as recovery) and robustness were established.The methodology was adapted from the Chilean Standard for the detection of histamine and other biogenic amines in fish andshellfish ME-711.O4-070, 2014, so it was necessary to implement adjustments for its application in urine. The results showedthat amino acids (AAs) did not cause interference in the analysis of PAs, and allow determination of concentrations in thelinear range between 4 and 28 μg/mL. However, good recovery (accuracy) was not obtained in the experiment, possiblybecause the standards used were not acetylated (42.6% Pu and 69% Cdv). The present methodology allows determining thelevels of Pu, Cdv, Spd, Spm Hst and Efd in urine samples from humans and other mammalian species.

The Mexican Regulations on milk classifies a product as adulterated when it has either undergone treatment that conceals its alteration and/or defects in its process or in the sanitary quality of the raw materials, among other criteria. The principal, most widely known adulterants incorporated into milk, include those added to increase milk volume and mask acidification. Milk should also test negative for the presence of inhibitors,e.g. antibiotics or disinfectants. The objective of this work was to determine the LOD for starches, sucrose, gelatin, chlorinated disinfectants; oxidants, quaternary ammonium and 14 most widely used microbial growth inhibitors in milk. This is because although the prohibition of these substances is clearly established, the detection limits (LOD) are not declared in the current regulation. With this finality, qualitative chemical analytical methodologiesfor detection of adulterants described in the Mexican Standards were implemented, as well as for the Yogurt Inhibition Test. Microbiological quality skim milk powder was used as a negative control, and the commercial culture YO-MIX ™ was used for the Yogurt Inhibition Test. The following LOD were obtained by chemical methods for starches (125and250 mg/kg), gelatin (250 mg/kg), hydrogen peroxide (6 mg/kg), sodium hypochlorite (25 mg/kg), benzalkonium chloride (12 mg/kg), N-Alkyl (C12,16) -N, N-dimethyl-N-benzylammonium (6 mg/kg). The yogurt test showed higher LOD for the disinfectants: 25,000 mg/kg for sodium hypochlorite and 60 mg/kg for the quaternary ammonium compounds. On the other hand, although oxidants were not detectable the yogurt testwas sufficiently sensitive to detect the Maximum Residue Limits (MRLs) for the 14 antimicrobials tested. Carrying out both types of tests, chemical and yogurt, to determine disinfectants and inhibitors at the levels of interest in milk is recommended.

In this study two experiments were carried out, the effect of a diet supplemented with fructans of Agave tequilana Weber, was analyzed in Hy-line hens in regards to their egg quality and production as well as on the levels of the polyamines, putrescine, spermidine and spermine in their feces. In the first study 300 Hy-line W-36 hens per group, which were aged 36 weeks, were randomly separated as follows for each of the three treatments. One group of 100 hens was fed with a diet supplemented with 0.1% fructans. Another group of 100 hens was supplemented with 0.2% fructans and a group of 100 hens without any fructans was added as a control group. Feed consumption was lower in the supplemented groups compared to the control group (p<0.05). Egg yolk quality was measured using Haugh units. The quality of the shell was studied using an Egg Force reader (g pressure/mm 2 ). Putrescine levels was measured in 10 animals in each group. In the second study, 1,155 laying hens, aged one day from the Hy-line W-35 genetic line were also randomly divided into three groups containing 385 hens in each one (A, B, C). Egg laying levels and weight was measured during 35 weeks. The egg laying percentage increased considerably in hens ingesting supplemented diets (p<0.05) and the egg weight was greater mainly in the supplementation with 0.1% fructans (p<0.05). Thus, it was shown that diet supplementation with fructans of agave improves egg quality and homeostasis and food consumption in the Hy-line hen.