Manuel López

Foodborne illnesses caused by Salmonella Typhimurium remain a major public health concern worldwide. Although ST19 has historically been a dominant lineage within this serotype, ST213 has become increasingly prevalent in Mexico. The biological factors underlying this epidemiological shift remain incompletely understood. In this study, we compared virulence-associated gene repertoires and stress-related phenotypes in representative S. Typhimurium ST19 and ST213 strains with distinct virulotypes (VTs). Comparative genomic analysis identified 119 virulence-associated genes distributed across 26 VTs, with most genes broadly conserved between genotypes. Representative strains were evaluated under simulated gastrointestinal tract (GIT) stress conditions, in post-stress recovery assays, and in a Caenorhabditis elegans infection model. Under the experimental conditions evaluated, the representative ST213 strains SAL109 (VT1), SAL115 (VT1), and SAL016 (VT12) tended to show higher persistence under host-associated stress conditions and greater intestinal colonization capacity in C. elegans than the ST19 strain SAL004 (VT23). However, strains sharing the same VT did not necessarily exhibit similar phenotypes, indicating that virulence-associated gene repertoires alone do not fully explain stress tolerance or host colonization behavior. Overall, these findings highlight phenotypic variability among strains with similar virulence gene content and support the importance of integrating genomic and phenotypic approaches to better understand the biology of emerging S. Typhimurium lineages.

Diets high in fat and refined carbohydrates reliably mimic key features of metabolic dysfunction-associated fatty liver disease (MAFLD), including hepatic lipid accumulation, oxidative stress, and ongoing liver injury. This study evaluated the long-term, low-dose administration of Callistemon citrinus ethanolic leaf extract and its primary bioactive compounds: d-limonene, ellagic acid, gallic acid, and p-coumaric acid to prevent lipotoxicity in rats fed a high-fat–sucrose diet (HFSD). Sixty male Wistar rats were randomly divided into 10 groups: normal control group, an untreated HFSD group, and eight HFSD groups treated for 23 weeks with metformin, C. citrinus extract, the individual bioactive compounds, or a mixture of these compounds. We assessed body and organ weights, liver macroscopic features, serum markers of liver injury, oxidative stress biomarkers, histopathological changes, and hepatic fatty acid profiles. HFSD feeding induced significant body weight gain, hepatomegaly, severe tissue damage, elevated serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), glucose and triglycerides, alongside heightened hepatic oxidative stress, and altered saturated fatty acid profiles. Conversely, treatment with metformin and the natural compounds attenuated HFSD-induced liver injury to varying degrees. Improvements in histopathological severity and serum liver enzymes correlated with decreased oxidative stress biomarkers. Notably, ellagic acid, gallic acid, d-limonene, and the bioactive mixture, significantly improved hepatic fatty acid profiles, whereas p-coumaric acid exhibited more modest effects. These results demonstrate that long-term administration of low-dose treatment can successfully improve all evaluated metabolic, biochemical, and histological parameter, suggesting that modulating oxidative stress and liver lipid composition is strongly linked to the mitigation of liver injury in this experimental MAFLD model.

Background. The nopal is a plant that adapts to various agroecosystems. Its nutritional and nutraceutical characteristics make it important for human and animal consumption. New strategies are required to increase its production and nutritional qualities. Objective. To determine the effect of biofertilization (inoculation of Pseudomonas sp., Enterobacter sp., and Paenibacillus sp.) of the vegetable nopal (VN; O. ficus-indica) crop on morphology, physicochemical and phytochemical composition and its relationship with biomass production (BP). Methodology. The research was carried out in a plot with an area of 750 m2 divided into four blocks, each with five treatments (n= 50 VN plants/treatment). The treatments (T) were: T1, chemical fertilizer; T2, bovine compost; T3, chemical fertilizer plus bioinoculant; T4, bovine compost plus bioinoculant and T5, Control (plants without fertilizer). The physicochemical and phytochemical composition, morphology, and crude protein (CP) of cladodes by treatment and harvest were evaluated (two harvests, with an interval of 45 days between each one). The information was analyzed using fixed effects models and principal component analysis (PCA). The differences between treatments were determined by the least squares means test at α<0.05. Results. Treatment effect (p0.05). Dry matter (DM) was lower (p<0.05) in the T4 (9.9%). PC showed higher values in the T1 (p<0.05): 9.3%. Total flavonoids were higher (p<0.05) in the T1 (1.29 mg EQ/g) and T4 (1.20 mg EQ/g). Antioxidant activity was lower (p0.05). The highest BP, according to the PCA, was observed in the T2 (24.1 kg/harvest) and, this BP was explained by two components (p<0.001): Component 1 (PC, FC and, cladode width) and Component 2 (DM). Implications. The findings of this work serve as a basis for future research aimed at maximizing the production of nopal vegetables - grown in low-fertility and clayey soils - through biofertilization. Conclusion. Soil fertilization with bovine compost (T2) is a viable strategy to increase the CP of VN, due to the improvement of the physicochemical, phytochemical, and morphological indicators, which contribute to the increase in the BP of this nopal cultivated in clayey soils with low fertility.

The objective was to determine the effects of back fat thickness (BFT) and body weight (BW) of gilts at the time of service on their productive performance during gestation and lactation in a commercial herd. BFT and BW were measured at the time of service, when entering maternity and weaning. Gilts were classified into tertiles according to BFT (low [< 17 mm], moderate [17–15 mm], and high [> 20 mm]) and BW (light [< 140 kg], moderate [140–150 kg], and high [> 150 kg]) at the time of service. A higher ( p < 0.05) lactating feed intake (4.5 kg/day) was observed in gilts with BFT < 17 mm. Classification based on BW at the time of service did not show any differences in feed intake during lactation. The greatest ( p < 0.05) loss of back fat (4.7 mm) during lactation was observed in gilts with a BFT > 20 mm. The total number of piglets born, piglets born alive, and weaned piglets was higher ( p < 0.05) in gilts with a BFT of 17–20 mm. In summary, it was shown that feed intake, weight loss, back fat during lactation, and litter performance were mostly affected by the BFT with respect to BW.

Context: In sows, the development of insulin resistance (IR) during late gestation and lactation favours a productive gap associated with low feed intake during lactation, which is reflected in the herd profitability. Therefore, the development of rapid-use tests to diagnose IR on farms will be very useful. Aims: We aimed to validate the triglyceride and glucose (T-G) index as a rapid diagnostic test to diagnose IR in sows during late gestation and lactation. Methods: The homeostatic model to evaluate IR (HOMA-IR) was used as a reference. Sixty sows (farrowing 1–5) were selected for blood sampling during late gestation and lactation. In the total number of samples collected (n = 480), the glucose, insulin, and triglyceride concentrations were determined to estimate the HOMA-IR and T-G index. Receiver operating characteristic curves were used to determine cut-off values for diagnosing IR using the T-G index. Key results: The highest (P < 0.05) values of HOMA-IR and T-G index were found between Day 110 of gestation and Day 3 of lactation, regardless of the farrowing number evaluated. The area under the curve for the T-G index was 0.83 (95% CI 0.78–0.88). The best overall cut-off point for diagnosing IR by using the T-G index was 4.24 (86% sensitivity and 77% specificity). The association between the T-G index and HOMA-IR was 0.68 (P < 0.0001), regardless of the farrowing number and productive stage (late gestation, early lactation, and late lactation). According to the farrowing number and productive stage, the best cut-off points were 4.21 (sensitivity 86% and specificity 73%), 4.20 (sensitivity 83% and specificity 73%), and 4.20 (sensitivity 88% and specificity 92%) for sow’s first and fourth farrowing, and late gestation respectively. Conclusions: The T-G index is a reliable field test for IR diagnosis in sows during late gestation and lactation. Implications: The T-G index test evaluated for the diagnosis of IR in sows is an approach that could be significantly exploited at the farm level. This test could become a support tool to maximise the productivity of the sow, since the development of IR could be modulated through zootechnical practices.

The aim of the present study was to evaluated hemoglobin A1c (HbA1c), the hemoglobin glycation index (HGI), and triglyceride and glucose (TG) index as predictive indicators for low feed intake in lactating sows due to glucose intolerance. Cactus (Opuntia ficus-indica) was included in sow diets as a modulating factor of glucose. Thirty-six sows were separated into three groups (Gs). Although the three groups received a conventional diet during gestation and lactation, 2.0 kg per sow per day of steam-cooked cactus (G1) and fresh cactus (G2) were added to the lactation diet as a glycemic modulating factor, with G3 serving as the control group. Glycemia was assessed via glucometer (blood glucose concentrations), HbA1c and HGI. For each indicator of glycemia the triglycerides and glucose (TG) index was evaluated. The highest blood glucose concentration was observed on day 3 of lactation (88.2 mg/dL). The average glycemic concentrations obtained from HbA1c on farrowing day (61.6 mg/dL) and day 21 of lactation (65.6 mg/dL) were lower (p<0.05) than those measured by a glucometer on the same days (71.8 and 77.7 mg/dL for farrowing day and day 21 of lactation, respectively). At farrowing, the TG index obtained from the HGI indicated that 83.0% of sows were glucose intolerant, compared to 100% according to the TG index obtained from a glucometer. At weaning, 50% of G2 did not show glucose intolerance when the TG index was calculated using the HGI, compared to 54% when it was calculated with blood glucose concentrations measured by a glucometer. All G3 sows presented glucose intolerance, regardless of the test used. The HbA1c, HGI, and TG index tests are viable alternatives to predict low feed intake due to glucose intolerance in lactating sows.

This study evaluated the effect of Opuntia ficus-indica L. supplementation on gilts during late gestation and lactation, particularly on their biochemical parameters and voluntary feed intake (VFI) at lactation. Thirty-two gilts were randomly distributed into two groups: control group (CG), gilts fed conventionally and experimental group (EG), gilts fed commercial feed plus O. ficus-indica. Glucose concentration was lower (P < 0.05) in the EG. Insulin concentration was higher in the gilts that consumed O. Ficus-indica. Triglyceride’s concentration was lower (P < 0.05) at gestation, farrowing and lactation in the EG. Total cholesterol was higher (P < 0.05) in gestation and lactation in the CG. HDL present higher concentration in lactation in the gilts that consumed O. Ficus-indica. LDL concentration was higher (P < 0.05) in gestation and lactation in the CG. Leptin concentration was higher (P < 0.05) at lactation in the CG. The gilts of the EG had higher VFI (22.6% more) and presented less body weight loss (3.7% less) at weaning (P < 0.05). These findings suggest that O. Ficus-indica favourably regulates the biochemical indicators involved in the development of insulin resistance, and this is reflected in the higher VFI and lesser body weight loss at weaning.

The regulation of sows’ metabolic state during the gestation-lactation transition is a requirement for a higher feed intake in lactation, an important aspect in improving animal welfare in current swine production systems. The present study aimed to evaluate the effects of the inclusion of different cactus (Opuntia ficus-indica L.) levels in the diet of gilts during late gestation and lactation on their biochemical parameters and voluntary feed intake during lactation. From day 85 of gestation until weaning, 40 gilts were divided into four groups: GNC (group with no cactus) with a basal diet (BD) only, G1C; group with 1% inclusion of cactus plus BD, G2C; group with 1.5% inclusion of cactus plus BD, and G3C; group with 2% inclusion of cactus plus BD. The dietary cactus supplementation increased the gilts’ feed intake (by 1.04 kg/day on average) during lactation and reduced their weight loss (4.3%) at weaning. The glucose concentrations were higher (range 73.0–83.9 mg/dL) in the GNC. The GNC had the highest triglyceride and cholesterol concentrations at day 100 of gestation. G3C had the highest osteocalcin concentration at day 100 of gestation. The highest feed intake and lowest glucose concentration were achieved with a cactus consumption of 1.04% in lactating gilts.