Although heavy metals are widely used as feed additives in animal production, little attention has been paid to the resistance of pathogenic bacteria to these elements. This study investigated heavy metal resistance in 215 isolates of avian pathogenic Escherichia coli from a collection of 308 isolates. All collection's strains were also tested against several antimicrobials using the disc diffusion method. Heavy metal resistance was determined by dilution in plates using Mueller Hinton agar incorporated with aqueous solutions of metals at critical concentrations. Except for copper, the study revealed high resistance rates for zinc (79.1 %), lead (59.1 %), and chromium (45.6 %). Lower rates were recorded for silver (17.7 %), cadmium (11.6 %), and mercury (8.4 %). A total of 29 diverse resistance profiles were identified, including 24 multi-resistant metallotypes displaying simultaneous resistance to up to 5 metals with the predominant metallotype involving resistance to zinc, lead, and chromium (20.5 %). Heavy metal resistance has frequently been associated with antibiotic resistance, particularly to beta-lactams and quinolones. This is supported by multiple correspondence analysis and independence test values (chi-square test) (P < 0.05), clearly establishing a link between antibiotic and heavy metal resistance in the tested strains. This is the first study in Algeria to highlight the dissemination of metal resistance among pathogenic E. coli isolates from poultry. The occurrence of heavy metal resistant pathogenic strains with zoonotic potential poses a serious public health threat, largely driven by co-selection pressure.
Reproductive performance in dairy cattle is highly susceptible to heat stress (HS), which negatively affects oocyte quality, fertilization, and early embryonic survival. Embryo transfer (ET) using in vitro-produced embryos may mitigate these adverse effects by allowing early embryonic development to occur under controlled laboratory conditions. Objective: To compare pregnancy rates following ET and artificial insemination (AI) in primiparous Holstein-Friesian cows exposed to chronic HS across seasons. Methods: A total of 275 primiparous Holstein-Friesian cows were assigned to ET (n = 124) or AI (n = 151). All cows underwent standardized hormonal synchronization protocols. Pregnancy diagnosis was performed by transrectal ultrasonography at 30 and 44 days post-service. A generalized linear model with binomial distribution was used to evaluate the effects of each reproductive method and season on pregnancy outcome. Results: The combined overall pregnancy rate was 33.5 %, with no significant differences between ET and AI across seasons (P > 0.05). Logistic regression analysis showed no significant effect of reproductive method (odds ratio = 1.07; 95 % Confidence interval: 0.64–1.78; P = 0.798) or season (P = 0.158) on pregnancy outcome. Although not statistically significant, a numerical trend favoring ET during summer was observed. Conclusions: Under chronic HS conditions, ET using in vitro-produced embryos did not significantly improve pregnancy rates compared with AI.
The study aimed at evaluating the protective effects of sandfish extract against cadmium (Cd)-induced testicular toxicity in male albino rats. Twenty-nine rats were divided into five groups: Control (n=5), Extract (n=5), Cadmium (n=6), Cd + Extract (n=7), and Cd + Medicine (n=6). The experiment lasted 56 days. Cd exposure did not impact body weight, but it was significantly harmful for testicular biometry, spermatogenesis efficiency, and antioxidant parameters. Sandfish extract had no significant impact on body weight or relative testicular weight. However, it showed improved tubular and intertubular compartments compared to Cd-exposed groups. Cd + Ext and Cd + Medicine partially restored several parameters but didn't match Control or Extract groups, highlighting sandfish extract's potential protective effects against Cd-induced reproductive toxicity.
This work aimed to evaluate intrinsic and extrinsic factors influencing in vitro embryo production (IVEP) efficiency in bovines under tropical conditions in Colombia. Retrospective data from 1 443 ovum pick-up (OPU) sessions conducted between 2020 and 2021 involving Brahman, Gyr, and Holstein cattle breeds were analyzed. Variables assessed included oocyte viability, cleavage rate, blastocyst yield, semen type (sex-sorted vs. conventional), IGF-I supplementation, seasonal climatic conditions, breed, and frequency of follicular aspiration. Results indicated significant effects of these factors on IVEP efficiency. The rainy season improved oocyte quality and embryo production, yielding a higher blastocyst rate per OPU (23.9 %) compared to dry (21.6 %) and transition seasons (19.6 %). The geographic location influenced all IVEP parameters, with higher embryo production rates in Montería compared to other regions. Conventional semen significantly increased embryo production rates (25.8 % Blast/OPU) compared to sex-sorted semen (17.9 % Blast/OPU). Supplementation with 100 ng/ml IGF-I significantly enhanced cleavage rates (76.3 %) and blastocyst yields (27.3 % Blast/OPU). While Brahman cows provided the highest number of oocytes, Gyr and Red Brahman breeds exhibited superior embryo development potential. Additionally, frequent follicular aspiration intervals (≤ 4 times) resulted in better embryo production compared to less frequent aspirations (> 5 times). These findings highlight critical factors for optimizing IVEP protocols under tropical conditions, suggesting strategic adjustments such as scheduling OPU sessions during favorable seasons, selecting suitable breeds and semen types, utilizing IGF-I supplementation, and optimizing follicular aspiration frequency to enhance embryo production efficiency in commercial cattle breeding programs.
This study aimed to produce two functional feed additives via solid-state fermentation and evaluate their effects on performance, meat quality, and cecal microbiota in broiler chickens. A total of 288 mixed-sex Ross 308 broiler chicks were randomly assigned to nine dietary treatments (four replicates of eight chicks each). The control group received a basal diet, while treatment groups received the basal diet supplemented with increasing doses (300–2 400 mg/kg) of either fermented tomato pomace plus oat or fermented apple pomace plus rye. The trial lasted 49 days. Supplementation with the lowest and highest doses of fermented apple pomace plus rye significantly increased body weight and body weight gain (P < 0.05). The fermented tomato pomace plus oat increased breast meat lightness and yellowness at higher doses, whereas the fermented apple pomace plus rye decreased both color parameters (P < 0.05). The cecal lactic acid bacteria population increased with both additives at 300 mg/kg (P < 0.05). Both fermentation products yielded functional additives that improved body weight and weight gain during the starter period. The fermented apple pomace plus rye at 300 mg/kg showed the most consistent positive effects and can be recommended as a potential alternative feed additive for broiler chickens.
