Genotyping of Toxoplasma gondii in domestic animals from Campeche, México, reveals virulent genotypes and a recombinant ROP5 allele.

Toxoplasma gondii has at least 318 genotypes distributed worldwide, and tropical regions usually have greater genetic diversity. Campeche is a state located in the southeastern region of México and has favourable climate conditions for the replication and dissemination of this protozoan, similar to those in South American countries where broad genetic diversity has been described. Thus, in this study, 4 T. gondii isolates were obtained from tissues of stray dogs and free-range chickens in Campeche, México, and were genotyped by Mn-PCR-RFLP with 10 typing markers (SAG1, altSAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico) and 5 virulence markers (CS3, ROP16, ROP17, ROP18 and ROP5) to provide new information about the distribution and virulence prediction of T. gondii genotypes. Two isolates of T. gondii genotype #116 and 2 of genotype #38 were obtained from stray dogs and chickens, respectively. The parasite load found in these species was between <50 and more than 35 000 tachyzoites per mg of tissue. Virulence marker genotyping revealed a recombinant 1&3 ROP5 RFLP pattern in 2 ToxoDB #116 isolates with no prediction of virulence in a murine model, while in the 2 ToxoDB #38 isolates, the ROP18/ROP5 combination predicted high virulence. Considering all the typed markers, there is a predominance of type I and III alleles, as constantly reported for the isolates characterized in various regions of México. It is crucial to determine their phenotype to corroborate the genetic virulence profile of the T. gondii isolates obtained in this study.

Prediction of Body Weight by Using PCA-Supported Gradient Boosting and Random Forest Algorithms in Water Buffaloes (Bubalus bubalis) Reared in South-Eastern Mexico.

This study aims to use advanced machine learning techniques supported by Principal Component Analysis (PCA) to estimate body weight (BW) in buffalos raised in southeastern Mexico and compare their performance. The first stage of the current study consists of body measurements and the process of determining the most informative variables using PCA, a dimension reduction method. This process reduces the data size by eliminating the complex structure of the model and provides a faster and more effective learning process. As a second stage, two separate prediction models were developed with Gradient Boosting and Random Forest algorithms, using the principal components obtained from the data set reduced by PCA. The performances of both models were compared using R2, RMSE and MAE metrics, and showed that the Gradient Boosting model achieved a better prediction performance with a higher R2 value and lower error rates than the Random Forest model. In conclusion, PCA-supported modeling applications can provide more reliable results, and the Gradient Boosting algorithm is superior to Random Forest in this context. The current study demonstrates the potential use of machine learning approaches in estimating body weight in water buffalos, and will support sustainable animal husbandry by contributing to decision making processes in the field of animal science.

Protein Supplementation as a Nutritional Strategy to Reduce Gastrointestinal Nematodiasis in Periparturient and Lactating Pelibuey Ewes in a Tropical Environment.

The study was carried out to evaluate the effect of energy and protein supplementation on parasitological and hematological response during peripartum and lactation of productive and non-productive Pelibuey ewes in a tropical environment. Forty-eight Pelibuey ewes aged 3-5 years and with a body weight of 31 ± 5 kg were used. Four groups of 12 ewes, including non-pregnant and productive ewes, were formed. A factorial treatment design was formulated, where two levels of energy (low, 9.6 MJ/kg, n = 24; and high, 10.1 MJ/kg, n = 24) and two levels of protein (high, 15% crude protein in diet, n = 24; and low, 8% crude protein in diet, n = 24) were studied. Fecal and blood samples were collected to determine the fecal egg count (FEC) of gastrointestinal nematodes (GIN), packed cell volume (PCV) and peripheral eosinophil (EOS) count. These variables were rearranged with respect to the lambing date in a retrospective study. The high dietary protein level had a significant effect on reducing the FEC and increasing the PCV of ewes during lactation, in comparison with animals fed with the low protein level. Differences in the study variables were attributed to physiological stage. Lactating ewes showed the highest FEC values (2709 ± 359 EPG), the lowest PCV values (21.9 ± 0.7%) and the lowest EOS (0.59 ± 0.6 Cells × 103 µL). It is concluded that high levels of dietary protein improve the hematological response and reduce the FEC in Pelibuey ewes under grazing conditions. The non-pregnant ewes maintained some resilience and resistance to GIN infection compared to productive ewes.

Haemonchus contortus infection induces a variable immune response in resistant and susceptible Pelibuey sheep.

The immune response and phenotypic characteristics of Pelibuey lambs were analysed after the induction of a Haemonchus contortus trickle infection. Male lambs (n = 29; 20 kg live weight) were infected with 100 H. contortus infective larvae per kg of live weight on day 3, 5 and 7 of the experiment. The number of eggs per gram (epg), seven haematological parameters and the immunoglobulin A (IgA) level were analysed for 56 experimental days. In addition, histopathological samples from the fundic abomasal region and the relative expression of 10 immune-related genes from 15 infected and three non-infected lambs were analysed at day 0 and 49 of the experiment. The epg count and some haematological parameters (leucocytes, red blood cells, haemoglobin and total protein) with statistically significant differences (P < 0.01) were used to identify nine resistant and 20 susceptible lambs (1166 ±â€¯1071 and 3171 ±â€¯1463 epg, respectively). Moreover, acute infiltration of immune cells and parasitic granuloma formation were observed in susceptible lambs; the resistant group had moderate inflammatory cell infiltration. With respect to relative gene expression, resistant lambs showed upregulation (P < 0.001) of 10 genes, from 2.2 to 15.99 fold. Moreover, there was a strong indirect correlation (P < 0.05) between the epg count and interleukin 5 (IL5) gene expression. By contrast, there was an average 0.34 fold downregulation in nine of the immune-related genes (P ≤ 0.05) in susceptible lambs (the only exception was Fc fragment of IgE receptor Ia [FCER1A] upregulation). In addition, there was a direct correlation (P ≤ 0.05) between the epg count and the expression of IL8, which encodes an inflammatory chemokine. In conclusion, this study showed differential IL5 and IL8 gene expression during haemonchosis in resistant and susceptible Pelibuey lambs, respectively, together with a variable immune response based on histopathological and haematological parameters.