Principais Coleções do Repositório
Submissões Recentes
Avaliação do uso de resíduo de tubos de papel em compósitos de fibrocimento submetidos à carbonatação acelerada
(Universidade Federal de Lavras, 2025-08-28) Teixeira Junior, Walmir dos Santos; Martins, Maria Alice; Silva, Danillo Wisky; Cruz, Thiago Moreira; Mendonça, Maressa Carvalho; Oliveira, Barbara Maria Ribeiro Guimarães de
This study aims to development and characterization of fiber cement composites reinforced with vegetable fibers, with emphasis on the incorporation of industrial waste from recycled paper tubes, and evaluation of the effect of the accelerated carbonation process on the properties of the obtained fiber cement. The research was structured in a scientific article covering chemical and morphological analysis of the fibers, manufacturing and physical, mechanical, and microstructural characterization of the composites, as well as the evaluation of the effects of accelerated carbonation on the durability and mechanical performance of the materials. The results indicate that the combination of vegetable fibers and recycled residues can improve important properties of fiber cement, while promoting sustainable alternatives for the construction sector. This work contributes to technological and environmental advancements in the field of biomaterials, pointing to future research directions focused on optimizing processes and materials.
Otimização multiobjetivo de fluxos rodoviários em terminais intermodais de grãos com inteligência artificial e simulação
(Universidade Federal de Lavras, 2025-07-18) Lima, Júlio César Sousa; Silva, Felipe Olivieira e; Ferreira, Danton Diego; Barbosa, Bruno Henrique Groenner; Tonelli, Adriano Olímpio; Silva, Felipe Olivieira e
The growing demand for logistical efficiency in the Brazilian agribusiness sector imposes significant challenges on the operation of intermodal grain terminals, especially under increasing pressure for sustainability, fairness, and responsible resource management. This dissertation proposes an integrated approach based on Discrete Event Simulation (DES) coupled with multiobjective optimization algorithms, with emphasis on the Non-dominated Sorting Genetic Algorithm II (NSGA-II), to enhance operational performance while mitigating social and environmental impacts. The proposed model simultaneously considers five conflicting objectives: (i) truck dwell time, (ii) unloading throughput, (iii) asset utilization, (iv) average operator fatigue, and (v) inequality in waiting times. In addition to computational modeling, the study incorporates ethical and human-centered criteria into the evaluation of solutions, aligning with the principles of Industry 5.0 and algorithmic governance. The results demonstrate the feasibility of identifying non-dominated solutions that balance efficiency, distributive justice, and sustainability. Despite progress in the literature on simulation and artificial intelligence applied to logistics, a significant research gap remains: few studies offer validated, multidimensional models that support real-world decision-making in complex operational settings such as intermodal grain terminals. This study contributes to bridging this gap by proposing and applying a replicable, ethically grounded, and technically robust model with potential for practical and institutional impact.
Mistura de raiz e da parte aérea da mandioca (manihot esculenta crants) em ração para frangos de corte tipo caipira
(Universidade Federal de Lavras, 2025-09-30) Santos, Edson da Silva; Fassani, Édison José; Freitas, Adriana Garcia de; Oliveira, Roberto Maciel de
This study aimed to evaluate the zootechnical and economic feasibility of including a mixture of cassava roots and aerial parts (Manihot esculenta Crantz) in the diet of slow-growing free-range broiler chickens as an alternative to the partial replacement of conventional feed ingredients. The experiment was conducted in a completely randomized design with three inclusion levels of the cassava mixture in the diets (0%, 20%, and 40%), five replicates, and seven birds per experimental unit. Chickens were reared from 45 to 90 days of age, and final body weight, feed conversion ratio, and feed production costs were evaluated. The results showed that the inclusion of the cassava mixture up to 40% did not significantly affect the final body weight of the birds at 90 days of age (p > 0.05), with a coefficient of variation of 14.31%, indicating satisfactory experimental precision. An increase in feed conversion ratio was observed with higher inclusion levels; however, productive performance remained within acceptable standards for alternative production systems. Economic analysis demonstrated a progressive reduction in feed costs and in the cost per kilogram of meat produced, especially at the 40% inclusion level. It is concluded that the use of cassava in its entirety is a technically feasible, economically advantageous, and sustainable alternative, contributing to production cost reduction and strengthening family farming in free-range poultry systems.
Aditivo antimicotoxinas melhora o desempenho de suínos desafiados com dietas contendo micotoxinas nas fases de creche e crescimento
(Universidade Federal de Lavras, 2025-07-09) Brito, Sara Kauane de; Silva, Bruno Alexander Nunes; Orientador; Abreu, Márvio Lobão Teixeira de; Naves, Luciana de Paula; Glória, Eduardo Micotti da; dc.contributor.referee1; dc.contributor.referee2; dc.contributor.referee3; dc.contributor.referee4; dc.contributor.referee5
The ingestion of mycotoxins can result in several adverse effects, including reduced growth rate and immunosuppression. The present study aimed to evaluate the impact of supplementation with an anti-mycotoxin additive, composed of bentonite, activated charcoal, yeast cell wall, a selenium–amino acid complex, and milk thistle extract, in diets containing added mycotoxins for piglets during the nursery and growing phases, on their performance and antioxidant status. A total of 56 weaned piglets, 24 days of age (average body weight 6.99 kg), were used. Piglets were housed in pens with two animals each, according to body weight, litter origin, and sex. Subsequently, the animals were transferred to the growing unit, and each pig was considered an experimental unit. Dietary treatments consisted of feeding pigs a standard control diet (negative control – NC; without mycotoxins or anti-mycotoxin additive); NC + AD (negative control supplemented with the anti-mycotoxin additive); a standard diet containing added mycotoxins considered as the positive control (Deoxynivalenol (DON): 1,700 μg/kg; Zearalenone (ZEA): 700 μg/kg; Aflatoxin (AFLA): 50 μg/kg; Ochratoxin A (OTA): 50 μg/kg; T-2 toxin: 400 μg/kg; Fumonisin (FUM): 5,000 μg/kg) without the anti-mycotoxin additive; and a positive control diet supplemented with 0.5 kg/ton of the anti-mycotoxin additive. Pigs were individually weighed at the beginning and end of each phase, and feed intake was recorded based on daily pen consumption throughout the experiment. On days 0, 7, and 36 post-weaning, blood samples were collected for oxidative stress analysis. Antioxidant enzymes (glutathione peroxidase [GPX], superoxide dismutase [SOD], and glutathione S-transferase [GST]), vitamin E, lipid peroxidation (LPO), and reduced glutathione (GSH) concentration were evaluated. Pigs exposed to mycotoxins and supplemented with the anti-mycotoxin additive showed improved performance and lower GST activity compared with pigs receiving only mycotoxincontaminated diets, possibly indicating a reduced need for activation of enzymatic defense pathways. Our results demonstrate that the use of an anti-mycotoxin additive may help reduce the negative impacts on performance and oxidative stress when animals are fed diets contaminated with multiple mycotoxins.
Blend de ácidos orgânicos em dietas para fêmeas suínas em gestação e lactação
(Universidade Federal de Lavras, 2025-04-29) Pereira, Thainara Sawia Barbosa; Silva, Bruno Alexander Nunes; Orientador; Abreu, Márvio Lobão Teixeira de; Naves, Luciana de Paula; Araujo, Wagner Azis Garcia de; Soares, Marcos Henrique; dc.contributor.referee1; dc.contributor.referee2; dc.contributor.referee3; dc.contributor.referee4; dc.contributor.referee5
Nutritional strategies such as the use of acidifiers can contribute to improving the performance of sows during gestation and lactation. The objective of this study was to evaluate the inclusion of an organic acid blend in the diet of mixed-parity sows during gestation and lactation, on the performance, blood parameters, and performance and composition of the intestinal microbiota of suckling piglets. A total of 300 mixed-parity sows were used, and the animals were distributed in a randomized block design, consisting of three treatments with 100 females per treatment, according to body weight on day 50 of gestation and parity order (1st, 2nd: Young; and 3rd-6th: Adult). The treatments consisted of CON (control diet, without inclusion of the acidifier); ACTLow (inclusion of 0.3% of the acidifier, ACTHigh (inclusion of 0.5% of the acidifier), the additive was supplied daily in an “on top” manner following the feeding curve of the sows, the supply started at 50 days of gestation and throughout the lactation period. Dietary supplementation with acidifier did not influence the reproductive performance of the sows and the productive performance of the piglets during lactation (P > 0.05). There was an effect of parity orders on body weight at farrowing and weaning, average daily feed intake and estimated daily milk production of the sows (P < 0.05). There was an effect of parity orders on plasma levels of ALT and NEFA at 80 days of gestation (P < 0.05). Supplementation with 0.5% of the acidifier tended to reduce AST at 80 days of gestation (P < 0.05) and reduced urea at 110 days of gestation. (P<0.05). The acidifier had no effect on the antioxidant enzymes of the sows, IgG, IgA and I-FABP in the serum of the piglets (P>0.05). ACTLow piglets showed a reduction in IL-6 and ACTHigh piglets a reduction in IL-12/IL23p40. Piglets belonging to ACTHigh showed greater microbial richness and diversity. Dietary supplementation with 0.5% organic acids improves protein digestibility, reducing AST at 80 days of gestation and plasma urea at 110 days. In addition, it promotes greater microbial abundance in the offspring and modulates the composition of the microbiota, without impacting the performance of sows and piglets during lactation.