Immunological indices of Giant African Land snails (Archachatina marginata) improved with fixed dose of vitamin C during acute heat stress

The study determined immunological indices of Giant African Land snail (Archachatina marginata) improved with fixed dose of vitamin C under acute heat stress (AHS). Prior to the AHS, vitamin C was administered for four weeks to two treatment groups, while other two treatment groups were not. Each treatment was monitored, haemolymph collected at 0, 30 and 60 minutes exposure times. Immunological cytokines: interferon gamma (IFN-γ) and interleukin 2 (IL-2); and total haemocyte counts (THC) were determined. Under AHS, vitamin C elevated (p <0.05) IFN-γ production (606.33 ± 302.86) compared to other groups with or without vitamin C administration (7.20 ± 1.58 vs. 73.20 ± 32.23 vs. 7.80 ± 1.36). IL-2 was not affected (p >0.05) by vitamin C under AHS. Highest (p <0.05) THC values was obtained with vitamin C administration under AHS, but reduced under no AHS. Exposure time affected (p <0.05) IFN-γ production and THC values, but not IL-2 (p >0.05). With fixed dose of vitamin C and exposure time, highest (p <0.05) IFN-γ values were obtained under AHS with vitamin C administration at 30 minutes and at 60 minutes in THC, compared to other groups. The study concluded that fixed dose of vitamin C at 150 mg kg-1 of feed was appropriate under AHS to boost the immune system of the animals.(AU)

Changes in expression of interferon-stimulated genes and ubiquitin activating enzyme E1-like in ovine thymus during early pregnancy

As the main signal for the maternal recognition in ruminants, interferon-tau (IFNT) stimulates expression of interferon-stimulated genes (ISGs) in uterus and many extrauterine tissues. However, it is unclear that early pregnancy induces expression of signal transducer and activator of transcription 1 (STAT1), myxovirusresistance 1 (Mx1), interferon-gamma-inducible protein 10 (IP-10) and ubiquitin activating enzyme E1-like protein (UBE1L) in maternal thymus. In this study, ovine thymuses were sampled on day 16 of the estrous cycle and on days 13, 16 and 25 of gestation, and the expression of STAT1, Mx1, IP-10 and UBE1L was detected by real-time quantitative PCR, Western blot and immunohistochemistry. The results revealed that the expression of STAT1 and IP-10 reached peaks on day 16 of pregnancy, and expression of Mx1 was enhanced on day 25 of pregnancy, and STAT1 protein was located in the epithelial reticular cells, capillaries and thymic corpuscles. However, expression of UBE1L was declined during early pregnancy. In conclusion, early pregnancy influences expression of STAT1, Mx1, IP-10 and UBE1L in maternal thymus, which may participate in regulation of maternal immune tolerance during early pregnancy in sheep.

Changes in expression of interferon-stimulated genes and ubiquitin activating enzyme E1-like in ovine thymus during early pregnancy

As the main signal for the maternal recognition in ruminants, interferon-tau (IFNT) stimulates expression of interferon-stimulated genes (ISGs) in uterus and many extrauterine tissues. However, it is unclear that early pregnancy induces expression of signal transducer and activator of transcription 1 (STAT1), myxovirusresistance 1 (Mx1), interferon-gamma-inducible protein 10 (IP-10) and ubiquitin activating enzyme E1-like protein (UBE1L) in maternal thymus. In this study, ovine thymuses were sampled on day 16 of the estrous cycle and on days 13, 16 and 25 of gestation, and the expression of STAT1, Mx1, IP-10 and UBE1L was detected by real-time quantitative PCR, Western blot and immunohistochemistry. The results revealed that the expression of STAT1 and IP-10 reached peaks on day 16 of pregnancy, and expression of Mx1 was enhanced on day 25 of pregnancy, and STAT1 protein was located in the epithelial reticular cells, capillaries and thymic corpuscles. However, expression of UBE1L was declined during early pregnancy. In conclusion, early pregnancy influences expression of STAT1, Mx1, IP-10 and UBE1L in maternal thymus, which may participate in regulation of maternal immune tolerance during early pregnancy in sheep.(AU)

Samsum ant venom modulates the immune response and redox status at the acute toxic dose in vivo

Background:Ant venoms express surface molecules that participate in antigen presentation involving pro- and anti-inflammatory cytokines. This work aims to investigate the expression of MHC-II, CD80 and CD86 on the polymorphonuclear cells (PMNs) in rats injected with samsum ant venom (SAV).Methods:Rats were divided into three groups - control, SAV-treated (intraperitoneal route, 600 μg/kg), and SAV-treated (subcutaneous route, 600 μg/kg). After five doses, animals were euthanized and samples collected for analysis.Results:The subcutaneous SAV-trated rats presented decreased levels of glutathione with increased cholesterol and triglyceride levels. Intraperitoneal SAV-treated animals displayed significantly reduced concentrations of both IFN-γ and IL-17 in comparison with the control group. However, intraperitoneal and subcutaneous SAV-treated rats were able to upregulate the expressions of MHC-II, CD80 and CD86 on PMNs in comparison with the control respectively. The histological examination showed severe lymphocyte depletion in the splenic white pulp of the intraperitoneal SAV-injected rats.Conclusion:Stimulation of PMNs by SAV leads to upregulation of MHC-II, CD 80, and CD 86, which plays critical roles in antigen presentation and consequently proliferation of T-cells. Subcutaneous route was more efficient than intraperitoneal by elevating MHC-II, CD80 and CD86 expression, disturbing oxidative stability and increasing lipogram concentration.(AU)

Samsum ant venom modulates the immune response and redox status at the acute toxic dose in vivo

Background:Ant venoms express surface molecules that participate in antigen presentation involving pro- and anti-inflammatory cytokines. This work aims to investigate the expression of MHC-II, CD80 and CD86 on the polymorphonuclear cells (PMNs) in rats injected with samsum ant venom (SAV).Methods:Rats were divided into three groups - control, SAV-treated (intraperitoneal route, 600 μg/kg), and SAV-treated (subcutaneous route, 600 μg/kg). After five doses, animals were euthanized and samples collected for analysis.Results:The subcutaneous SAV-trated rats presented decreased levels of glutathione with increased cholesterol and triglyceride levels. Intraperitoneal SAV-treated animals displayed significantly reduced concentrations of both IFN-γ and IL-17 in comparison with the control group. However, intraperitoneal and subcutaneous SAV-treated rats were able to upregulate the expressions of MHC-II, CD80 and CD86 on PMNs in comparison with the control respectively. The histological examination showed severe lymphocyte depletion in the splenic white pulp of the intraperitoneal SAV-injected rats.Conclusion:Stimulation of PMNs by SAV leads to upregulation of MHC-II, CD 80, and CD 86, which plays critical roles in antigen presentation and consequently proliferation of T-cells. Subcutaneous route was more efficient than intraperitoneal by elevating MHC-II, CD80 and CD86 expression, disturbing oxidative stability and increasing lipogram concentration.

Effects of thymoquinone on interleukin-1 and interferon gamma gene expression and antibody titers against newcastle disease in broiler chickens under oxidative stress

An experiment was conducted to determine the effects of the dietary inclusion of different levels of thymoquinone (TQ) of broilers subjected to oxidative stress or not on the antibody titers against Newcastle disease and on the gene expression of interleukine-1 and interferon gamma. A total of 320 one-day-old broilers was randomly assigned to eight treatments with four replicates of 10 birds each, in a 4 × 2 factorial arrangement, consisting of four thymoquinone (TQ) levels (0, 5, 8, or 11 mg/kg body weight) and two levels tert-butyl hydroperoxide (t-BHP) injection (0 or 0.02 mmol/kg of body weight). Blood samples were collected from two birds per replicate to determine antibody titers against Newcastle disease. At the end of experiment, two birds per replicate were randomly selected, sacrificed and their spleens were collected to evaluate the genes expressioninterleukin-1 and interferon gamma (p 0.05). The dietary inclusion of TQ of broilers subjected or not oxidative stress increased antibody production against Newcastle disease (p 0.05). Both individual and combined dietary inclusion of t-BHP and TQ promote the differentiation and proliferation of spleen cells and the gene expression of interleukin-1 and interferon gamma (p 0.05).

Effects of thymoquinone on interleukin-1 and interferon gamma gene expression and antibody titers against newcastle disease in broiler chickens under oxidative stress

An experiment was conducted to determine the effects of the dietary inclusion of different levels of thymoquinone (TQ) of broilers subjected to oxidative stress or not on the antibody titers against Newcastle disease and on the gene expression of interleukine-1 and interferon gamma. A total of 320 one-day-old broilers was randomly assigned to eight treatments with four replicates of 10 birds each, in a 4 × 2 factorial arrangement, consisting of four thymoquinone (TQ) levels (0, 5, 8, or 11 mg/kg body weight) and two levels tert-butyl hydroperoxide (t-BHP) injection (0 or 0.02 mmol/kg of body weight). Blood samples were collected from two birds per replicate to determine antibody titers against Newcastle disease. At the end of experiment, two birds per replicate were randomly selected, sacrificed and their spleens were collected to evaluate the genes expressioninterleukin-1 and interferon gamma (p 0.05). The dietary inclusion of TQ of broilers subjected or not oxidative stress increased antibody production against Newcastle disease (p 0.05). Both individual and combined dietary inclusion of t-BHP and TQ promote the differentiation and proliferation of spleen cells and the gene expression of interleukin-1 and interferon gamma (p 0.05). (AU)

PERFIS DE EXPRESSÕES DE GENES DA IMUNIDADE INATA QUANTO AO TECIDO LINFOIDE E CARACTERIZAÇÃO DA REGIÃO 3-UTR DO GENE DO INTERFERON-GAMA ASSOCIADO AO SEU PADRÃO DE EXPRESSÃO GÊNICA NA MEMBRANA CONJUNTIVAL DE BUBALINOS DA AMAZÔNIA

A bubalinocultura vem apresentando elevado desempenho nos últimos anos, especialmente na Amazônia Brasileira, embora esta apresente condições ambientais adversas que influenciam no surgimento de doenças, incluindo infecções oculares. Assim, a determinação de genes relacionados à imunidade inata ocular é necessária em populações bubalinas. Buscamos determinar os perfis de expressão de genes relacionados ao sistema imune inato na membrana conjuntival de búfalos da Amazônia e caracterizar a região 3-UTR do gene Interferon gama determinando o seu perfil de expressão nessa população. Para isso, amostras de tecido conjuntival ocular e sangue foram coletadas de búfalos abatidos no Estado do Amapá. Os animais foram classificados em três grupos (G1, G2 e G3) de acordo com o grau quantitativo de tecido linfoide associado à conjuntiva por técnicas histológicas das amostras conjuntivais as quais foram submetidas a quantificação da expressão de citocinas inflamatórias, receptores tolllike 4 e -defensina-110 relativa ao gene endógeno. Amostras de sangue foram submetidas a PCR convencional usando iniciadores da região 3 UTR do gene Interferon gama. Os produtos foram purificados, sequenciados e as sequências editadas com outras correspondentes de búfalos e de espécies mamíferas. As mesmas foram alinhadas e comparadas a partir da análise de similaridade genética e análise filogenética. Na conjuntiva dos animais do G1 houve expressão apenas para IFNG e TLR4. Enquanto o G2 houve alta expressão para os genes IL6, IL10, IFNG, TLR4 e os animais do G3 apresentaram elevada expressão para todos os genes estudados. O grau de similaridade genética formou os grupos dos ruminantes, primatas, carnívoros, quirópteros, cetáceos e indivíduos isolados como suiformes e rinocerontes. Ruminantes e cetáceos apresentam alta relação filogenética enquanto houveram diferentes distâncias evolutivas de búfalos com as demais espécies de mamíferos. Nossos estudos serviram para definir os processos imunológicos inatos que ocorrem na membrana conjuntival de uma população de búfalos e determinar o perfil evolutivo em relação a outras espécies mamíferas.

Buffalo production has shown high performance in recent years, especially in the Brazilian Amazon, although it presents adverse environmental conditions that influence the emergence of diseases, including eye infections. Thus, the determination of genes related to ocular innate immunity is necessary in buffalo populations. We sought to determine the expression profiles of genes related to the innate immune system in the conjunctival membrane of Amazon buffaloes and to characterize the 3-UTR region of the Interferon gamma gene, determining its expression profile in this population. For this purpose, samples of ocular conjunctival tissue and blood were collected from buffaloes slaughtered in the State of Amapá. The animals were classified into three groups (G1, G2 and G3) according to the quantitative degree of lymphoid tissue associated with the conjunctiva by histological techniques of the conjunctival samples which were also subjected to quantification of the expression of inflammatory cytokines, tolllike receptors 4 and -defensin-110 relative to the endogenous gene. Blood samples were subjected to conventional PCR using primers from the 3' UTR region of the Interferon gamma gene. The products were purified, sequenced and the sequences edited with corresponding ones from buffalo and mammalian species. They were aligned and compared based on genetic similarity and phylogenetic analysis. In the conjunctiva of animals from G1 there was expression only for IFNG and TLR4. While G2 there was high expression for genes IL6, IL10, IFNG, TLR4 and animals from G3 showed high expression for all genes studied. The degree of genetic similarity formed the groups of ruminants, primates, carnivores, bats, cetaceans and isolated individuals such as suiformes and rhinos. Ruminants and cetaceans have a high phylogenetic relationship while there were different evolutionary distances between buffaloes and other mammal species. Our studies served to define the innate immunological processes that occur in the conjunctival membrane of a buffalo population and to determine the evolutionary profile in relation to other mammalian species.

Uso de dipeptídeo de metionina sobre a morfometria, parametros sanguineos e oxidativos e expressão de genes associados ao transporte de aminoácidos, sistema imune em frangos de corte desafiados por Eimeria spp.

O crescimento do animal é dependente, de diversos fatores, dentre estes, a obtenção adequada de nutrientes pelo intestino, uma vez que, o máximo potencial de crescimento é limitado pela taxa de nutrientes disponíveis no organismo. A coccidiose é uma doença infecciosa comum na avicultura mundial, causada por protozoários do gênero Eimeria, e é caracterizada por causar vários danos no intestino delgado e ceco das aves, com prejuízos sobre os processos de digestão e absorção dos nutrientes, e por afetar o desempenho animal. O fornecimento de rações com nutrientes essenciais como, por exemplo, a metionina, quando suplementada em níveis adequados pode ser útil para aliviar os efeitos negativos produzidos por esses agentes patogênicos. Nesse sentido, este trabalho teve como principal objetivo avaliar os efeitos do desafio por Eimeria spp. e da suplementação de metionina na forma de aminoácido livre (DL-Met) e de dipeptídeo (DL-MMet) sobre o desempenho, peso relativo de órgãos, estado redox, expressão de genes envolvidos com o transporte de aminoácidos e peptídeos, genes envolvidos no sistema defesa antioxidante e imune, genes relacionados com a produção de mucina, apoptose e proliferação celular no jejuno, bem como parâmetros morfométricos do jejuno e parâmetros sanguíneos. Para isto, frangos de corte machos de 10 dias de idade, foram divididos em seis tratamentos referentes ao desafio por Eimeria spp. (aves desafiadas: EC; ou aves não desafiadas: UC) e suplementação de metionina (sem suplementação de metionina: NS, suplementação de metionina na forma de aminoácido livre: DL-Met, e suplementação de metionina na forma de dipeptídeo: DL-MMet). Aos 14 dias de idade, os animais pertencentes ao grupo experimental EC receberam por via oral 1 mL de solução contendo oocistos esporulados de Eimeria spp. (E. acervulina, E. maxima, E. praecox e E. mitis). O restante dos animais (UC) receberam por via oral 1 mL de solução salina. Os animais foram abatidos por deslocamento cervical seis dias depois da inoculação (6 dpi), aos 20 dias de idade. Capítulo IV: Neste experimento, os frangos foram desafiados com quatro espécies de Eimeria (E. acervulina, E. maxima, E. praecox e E. mitis). Seis dias depois da inoculação, os animais foram abatidos e o jejuno foi coletado. Foi avaliado o desempenho dos animais, peso relativo dos órgãos, o estado redox do jejuno e a expressão de genes relacionados ao processo de absorção de aminoácidos e peptídeos, sistema antioxidante e imune no jejuno. Foi observado que os frangos EC apresentaram uma redução de 13% no consumo de ração, (CR), 37% de redução no ganho de peso (GP) e um aumento de 39% na taxa de conversão alimentar (CA). Com relação à suplementação de metionina, os frangos, consumindo a dieta DL-Met, apresentaram maior GP (aproximadamente 12% maior) e melhor CA (aproximadamente 12% menor), do que os frangos alimentados com a dieta NS. Frangos EC também apresentaram menor peso relativo da bursa de Fabricius (51,8%) e maiores pesos relativos do baço e do intestino total (delgado e grosso) (53,6% e 26,3%, respectivamente) do que os frangos UC. O desafio por Eimeria spp. causou um aumento nos níveis de nitrito e substâncias reativas ao ácido tiobarbitúrico (TBARS) no jejuno de frangos 6 dpi. Entre os frangos UC, aqueles, consumindo a dieta DL-Met, apresentaram maior capacidade antioxidante total (TAC) e menor atividade das enzimas antioxidantes catalase (CAT) e superóxido dismutase (SOD). Frangos EC, consumindo a dieta NS, também apresentaram maior teor de proteína carbonilada (CP) no jejuno 6 dpi. Adicionalmente, foi observado que os frangos alimentados com as dietas DL-Met e DL-MMet apresentaram menor teor de nitrito. O desafio por Eimeria spp. suprimiu a expressão dos genes catalase (CAT), superóxido dismutase 1 (SOD1), transportador de aminoácido neutros 1 (B0AT1), transportador de peptídeos 1 (PEPT1), receptor toll like 5 (TLR5), interleucina 2 (IL2), e ocludina (OCLN). O desafio por Eimeria spp. aumentou a expressão dos genes transportador de aminoácidos catiônicos 1 (CAT - 1) e interferon gama (INFG) no jejuno 6 dpi. O maior nível de expressão de PEPT1 foi observado em frangos alimentados com a dieta DL-MMet, e o menor nível de expressão do TLR5 foi observado em frangos consumindo a dieta NS. Capítulo V: Neste experimento, os frangos foram desafiados com Eimeria spp. (E. acervulina, E. maxima, E. praecox e E. mitis), e seis dias depois da inoculação, os animais foram abatidos para a coleta de sangue e do jejuno. Foi avaliado o desempenho dos animais, a morfometria do jejuno, a quantificação de células caliciformes neutras e ácidas, e os linfócitos intraepiteliais (LIEs) no jejuno. Também foi avaliada no jejuno a expressão de genes relacionados à produção de mucina e genes envolvidos nas vias de apoptose e proliferação celular. Adicionalmente, foi avaliada a atividade das enzimas aspartato aminotransferase (AST) e creatina quinase (CK), e o conteúdo de ácido úrico (AU) e creatinina (Cr) no plasma sanguíneo. No soro sanguíneo, foi avaliado o conteúdo de mucoproteínas (MUCO) e proteínas totais (PT). Foi observado que os animais desafiados por Eimeria spp. apresentaram pior desempenho independentemente da dieta consumida. Com relação à suplementação de metionina, os animais, recebendo a dieta DL-Met, apresentaram maior GP e menor CA. Os animais do grupo EC recebendo dieta NS, apresentaram vilosidades mais baixas e mais largas, com maior valor de profundidade de cripta, menor relação vilo:cripta, menor quantidade de células caliciformes neutras e menor expressão do gene mucina 2 (MUC2). Além disso, os animais EC, consumindo a dieta NS, apresentaram também a menor área de superfície de absorção do jejuno. Os animais EC, consumindo a dieta DL-MMet, apresentaram maior altura dos enterócitos, e também observamos que os animais EC apresentaram maior largura da lâmina própria que os animais UC. Houve efeito da dieta sobre a largura da lâmina própria: animais consumindo a dieta DL-MMet apresentaram menor valor de largura da lâmina própria. Animais UC, consumindo a dieta DL-Met, apresentaram maior quantidade de células caliciformes ácidas, e os animais EC, recebendo a dieta DL-MMet, apresentaram a maior quantidade de LIEs. Os animais EC apresentaram menor expressão dos genes caspase 3 (CASP3), linfoma de células B2 (BCL2), alvo mecanicista da rapamicina (MTOR) e proteína ribossomal quinase B1 (RPS6KB1) do que os animais UC. A atividade das enzimas AST e CK também foi influenciada pela presença do patógeno com maiores valores em animais EC e NS. Os animais EC apresentaram menor conteúdo de AU. A produção de MUCO foi maior nas aves EC, e o menor conteúdo de PT foi observado nas aves EC, consumindo a dieta DL-MMet. Em resumo, esses resultados confirmam que o desafio por Eimeria spp. prejudica o desempenho dos animais. Possivelmente, como consequência da indução da resposta imune e do estresse oxidativo, que junto com a progressão da coccidiose, causa a destruição celular do jejuno, afetando negativamente a expressão de importantes genes que codificam proteínas transportadoras de nutrientes. A maior parte dos resultados são inéditos, e mostram que a suplementação com metionina como aminoácido livre ou dipeptídeo ajuda a proteger as células intestinais de frangos de corte sob condição de desafio por Eimeria spp., contra o dano oxidativo principalmente através da sua função antioxidante. Foi possível concluir ainda, que a suplementação de metionina na forma de dipeptídeo nas dietas de frangos, sobretudo em condições de desafios sanitários, poderia funcionar como um importante elemento capaz de manter a morfologia e função das células intestinais.

The growth of the animal is dependent of several factors, among them, the adequate obtaining of nutrients by the intestine, since, the maximum potential of growth is limited by the rate of available nutrients in the organism. Coccidiosis is a common infectious disease in poultry farming worldwide, caused by protozoa of the genus Eimeria, and it is characterized by causing various damages to the small intestine and cecum of birds, impairing the processes of digestion and absorption of nutrients, and by affecting performance animal. The provision of feed with essential nutrients such as methionine when supplemented at appropriate levels may be useful to alleviate the negative effects produced by such pathogens. In this sense, this work had as main objective to evaluate the effects of the challenge by Eimeria spp. and methionine supplementation in the form of free amino acid (DL-Met) and dipeptide (DL-MMet) on performance, relative weight of organs, redox state, expression of genes involved in the transport of amino acids and peptides, genes involved in the antioxidant and immune defense system, genes related to mucin production and cell proliferation in the jejunum, as well as morphometric parameters of the jejunum and blood parameters. For this, male broilers from 10 days of age were divided in six treatments related to the challenge by Eimeria spp. (challenged birds: EC, or unchallenged birds: UC), and methionine supplementation (non-supplemented: NS, methionine supplementation in free amino acid form: DL-Met, and methionine supplementation in the form of dipeptide: DL-MMet). At 14 days of age the animals belonging to the experimental group EC received orally 1 mL of solution containing sporulated oocysts of Eimeria spp. (E. acervulina, E. maximus, E. praecox and E. mitis). The rest of the animals (UC) received orally 1 mL of saline solution. The animals were slaughtered by cervical dislocation six days after inoculation (6 dpi) at 20 days of age. Chapter IV: In this experiment the broilers were challenged with four species of Eimeria (E. acervulina, E. maxima, E. praecox and E. mitis). Six days after inoculation the animals were slaughtered and the jejunum was collected. The performance of the animals, relative weight of organs, the redox state of the jejunum, and the expression of genes related to the process of amino acid and peptides absorption, antioxidant and immune system in the jejunum were evaluated. It was observed that EC chickens presented a 13% reduction in feed intake (FI), 37% reduction in body weight gain (BWG) and a 39% increase in feed conversion rate (FCR). With regard to methionine supplementation, chickens consuming the DL-Met diet presented higher WG (about 12% higher) and better FCR (about 12% lower) than chickens fed the NS diet. EC broilers also had lower relative weight of Fabricius bursa (51.8%), higher relative weights of the spleen and whole intestine (53.6% and 26.3%, respectively) than UC broilers. The challenge for Eimeria spp. caused an increase in the levels of nitrite and thiobarbituric acid reactive substances (TBARS) in the chicken jejunum 6 dpi. Among the UC chickens, those consuming the DL-Met diet presented higher total antioxidant capacity (TAC) and lower activity of antioxidant catalase (CAT) and superoxide dismutase (SOD) enzymes. EC chickens consuming the NS diet, also presented higher carbonylated protein (CP) content in the jejunum 6 dpi. Additionally, it was observed that the broilers fed the DL-Met and DL-MMet diets presented lower levels of nitrite. The challenge for Eimeria spp. suppressed the expression of the catalase (CAT), superoxide dismutase 1 (SOD1), neutral amino acid transporter (B0AT1), peptide transporter 1 (PEPT1), toll like receptor 5 (TLR5), interleukin 2 (IL2), and occludin (OCLN) genes. The challenge for Eimeria spp. increased expression of the cationic amino acid 1 transporter (CAT - 1) and interferon gamma (INFG) genes in the jejunum 6 dpi. The highest level of PEPT1 expression was observed in broilers fed the DL-MMet diet, and the lowest level of TLR5 expression was observed in chickens consuming the NS diet. Chapter V: In this experiment the chickens were challenged with Eimeria spp. (E. acervulina, E. maxima, E. praecox and E. mitis), and six days after inoculation the animals were slaughtered for blood and jejunum collection. The performance of the animals, jejunum morphometry, quantification of neutral and acidic goblet cells, and intraepithelial lymphocytes (LIEs) in the jejunum were evaluated. The expression of genes related to the production of mucin, and genes involved in apoptosis and cell proliferation pathways were also evaluated in the jejunum. Additionally the activity of the enzymes aspartate aminotransferase (AST) and creatine kinase (CK), and the content of uric acid (AU) and creatinine (Cr) in blood plasma were evaluated. In the blood serum the content of mucoproteins (MUCO) and total proteins (PT) were evaluated. It was observed that the animals challenged by Eimeria spp. presented worse performance independently of the diet consumed. With respect to methionine supplementation, animals receiving the DL-Met diet presented higher WG and lower FCR. The animals of the EC group receiving NS diet had lower and wider villi, with a greater value of crypt depth, lower villus:crypt ratio, less amount of neutral goblet cells and lower expression of the mucin gene 2 (MUC2). In addition, EC animals consuming the NS diet also had the smallest surface area of jejunum absorption. The EC animals consuming the DL-MMet diet showed higher height of the enterocytes, and we also observed that the EC animals showed a greater width of the lamina propria than the UC animals. There was diet effect on the width of the lamina propria: animals consuming the diet DL-MMet showed lower width value of the lamina propria. UC animals consuming the DL-Met diet presented higher amount of acidic goblet cells, and the EC animals receiving the DL-MMet diet had the highest number of LIEs. EC animals showed lower expression of caspase 3 (CASP3), B2-cell lymphoma (BCL2), mechanistic rapamycin target (MTOR) and ribosomal protein B1 (RPS6KB1) than UC animals. The activity of AST and CK enzymes was also influenced by the presence of the pathogen; with higher values in EC and NS animals. EC animals presented lower AU content. MUCO production was higher in EC birds, and lower PT content was observed in UC birds consuming the DL-MMet diet. In summary these results confirm that the challenge by Eimeria spp. impairs the performance of the animals. Possibly as a consequence of the induction of immune response and oxidative stress, which together with the progression of coccidiosis cause the cellular destruction of the jejunum, negatively affecting the expression of important genes encoding nutrient transport proteins. Most of the results are unpublished, and show that methionine supplementation as a free or dipeptide amino acid helps to protect intestinal cells from broiler chickens challenged by Eimeria spp. against oxidative damage mainly through its antioxidant function. It was also possible to conclude that methionine supplementation in the dipeptide form in broiler diets, especially under conditions of health challenges, could function as an important element capable of maintaining the morphology and function of intestinal cells.