Genomic regions, candidate genes, and pleiotropic variants associated with physiological and anatomical indicators of heat stress response in lactating sows.

BACKGROUND: Heat stress (HS) poses significant threats to the sustainability of livestock production. Genetically improving heat tolerance could enhance animal welfare and minimize production losses during HS events. Measuring phenotypic indicators of HS response and understanding their genetic background are crucial steps to optimize breeding schemes for improved climatic resilience. The identification of genomic regions and candidate genes influencing the traits of interest, including variants with pleiotropic effects, enables the refinement of genotyping panels used to perform genomic prediction of breeding values and contributes to unraveling the biological mechanisms influencing heat stress response. Therefore, the main objectives of this study were to identify genomic regions, candidate genes, and potential pleiotropic variants significantly associated with indicators of HS response in lactating sows using imputed whole-genome sequence (WGS) data. Phenotypic records for 18 traits and genomic information from 1,645 lactating sows were available for the study. The genotypes from the PorcineSNP50K panel containing 50,703 single nucleotide polymorphisms (SNPs) were imputed to WGS and after quality control, 1,622 animals and 7,065,922 SNPs were included in the analyses. RESULTS: A total of 1,388 unique SNPs located on sixteen chromosomes were found to be associated with 11 traits. Twenty gene ontology terms and 11 biological pathways were shown to be associated with variability in ear skin temperature, shoulder skin temperature, rump skin temperature, tail skin temperature, respiration rate, panting score, vaginal temperature automatically measured every 10 min, vaginal temperature measured at 0800 h, hair density score, body condition score, and ear area. Seven, five, six, two, seven, 15, and 14 genes with potential pleiotropic effects were identified for indicators of skin temperature, vaginal temperature, animal temperature, respiration rate, thermoregulatory traits, anatomical traits, and all traits, respectively. CONCLUSIONS: Physiological and anatomical indicators of HS response in lactating sows are heritable but highly polygenic. The candidate genes found are associated with important gene ontology terms and biological pathways related to heat shock protein activities, immune response, and cellular oxidative stress. Many of the candidate genes with pleiotropic effects are involved in catalytic activities to reduce cell damage from oxidative stress and cellular mechanisms related to immune response.

Effects of dietary electrolyte balance on performance, energy balance, and expression of genes related to acid-basic balance, absorption, and transport of nutrients in broilers.

The objective of this study was to evaluate the effect of dietary electrolyte balance (DEB) levels on performance characteristics (feed intake, FI; body weight gain, BWG; and feed efficiency, FE), energy balance (retained energy, RE; metabolizable energy ingested, MEI; heat production, HP; and energy retention efficiency, ERE), and the expression of genes related to acid-base balance, nutrient absorption, and transport in broilers from 1 to 21 days of age. A total of 245 male Cobb chickens were used in a completely randomized design with five DEB levels (110, 175, 240, 305, and 370 mEq/kg) and seven replicates of seven birds each. The inclusion of DEB levels influenced FE; 110 mEq/kg provided the better values for this characteristic both in the pre-initial phase and in the initial phase but was different only concerning 175 mEq/kg (1-7 days) and 240 mEq/kg (1-21 days). Birds that ingested diets with a level of 240 mEq/kg of DEB had a higher MEI and HP. This DEB level caused a lesser and greater expression of the SLC12A2 gene in the liver and the ATP1A1 gene in the intestine, respectively. On the other hand, the ATP1A1 gene was less expressed in the liver and kidney of broilers supplemented with 370 mEq/kg compared to a level of 110 mEq/kg. In general, a level of 110 mEq/kg DEB in the ration seems to be the most suitable for good performance, energy balance, and gene expression of broilers from 1 to 21 days of age.

Selection of reference genes for quantitative real-time PCR normalization in European quail tissues.

Coturniculture has been standing out as an industrial poultry activity in several countries around the world because of the several adaptive advantages of quails. Research that considers the analysis of gene expression can enhance this activity. This study aimed to analyze the stability of reference genes (RGs) in different tissues of quails (both males and females) for the recommendation of use in gene expression studies by the quantitative reverse transcription-polymerase chain reaction (RT-qPCR). The expression stability of ten RGs (ACTA1, ACTB, B2M, GAPDH, HMBS, SDHA, HPRT1, MRPS27, MRPS30, and RPL5) was analyzed in four tissues (breast muscle, abdominal fat, liver, and intestine), and assessed using the statistical tools geNorm, NormFinder, comparative ΔCq method, and BestKeeper. The HPRT1 gene was the most stable in all quail tissues tested, followed by MRPS27 and MRPS30 in breast muscle, B2M and RPL5 in abdominal fat, HMBS and B2M in the liver, and RPL5 and HMBS in the intestine. These results may help studies using RT-qPCR assays to assess quail tissues from both sexes because they provide data on the most stable genes, which should be tested as candidate RGs for other experimental conditions.

Comparison of gene expression of Toll-like receptors and cytokines between Piau and Commercial line (Landrace×Large White crossbred) pigs vaccinated against Pasteurella multocida type D.

We aimed to compare Toll-like receptors (TLR) and cytokines expression in local Piau breed and a Commercial line (Landrace×Large White crossbred) pigs in response to vaccination against Pasteurella multocida type D. Seronegative gilts for Pasteurella multocida type D and Mycoplasma hyopneumoniae were used, from which peripheral blood mononuclear cells (PBMC) were collected in four time points (T0, T1, T2 and T3; before and after each vaccination dose). For bronchoalveolar lavage fluid cells (BALF), we set groups of vaccinated and unvaccinated animals for both genetic groups. Gene expression was evaluated on PBMC and BALF. In PBMC, when we analyzed time points within breeds, significant differences in expression for TLRs and cytokines, except TGFß, were observed for Commercial animals. For the Piau pigs, only TGFß showed differential expression. Comparing the expression among genetic groups, the Commercial pigs showed higher expression for TLRs after first vaccination dose, while for IL2, IL6, IL12 and IL13, higher expression was also observed in T3 and IL8 and IL10, in T1 and T3. Still comparing the breeds, the crossbred animals showed higher expression for TNFα in T1 and T2, while for TGFß only in T2. For gene expression in BALF, vaccinated Commercial pigs showed higher expression of TLR6, TLR10, IL6, IL8, IL10, TNFα and TGFß genes than vaccinated Piau pigs. The Commercial line pigs showed higher sensitivity to vaccination, while in local Piau breed lower responsiveness, which may partly explain genetic variability in immune response and will let us better understand the tolerance/susceptibility for pasteurellosis.

Substituição do resíduo da produção de palmito da Palmeira Real Australiana (Archontophoenix alexandrae) na silagem de cana-de-açúcar em dietas de ovinos / Replacing of residue from production of palm Palm Royal Australian (Archontophoenix alexandrae) in silage of sugar cane in diets of sheep

Objetivou-se avaliar a composição química, consumo voluntário e digestibilidade aparente de dietas contendo resíduo oriundo da produção de palmito da palmeira Real Australiana (Archontophoenix alexandrae) em substituição à cana-de-açúcarem ovinos. Foram utilizados 12 ovinos com peso vivo médio de 23,3 ± 2,8 kg, mantidos em gaiolas metabólicas distribuídos em seis quadrados latinos 2x2 implementado em esquema fatorial 3 x 2 (três tipos de resíduo - folha, bainha e composta - e dois níveis de substituição do resíduo, 5% e 15%). Verificou-se maior consumo de matéria seca (MS), matéria orgânica (MO), carboidratos não fibrosos (CNF) na substituição pelo resíduo composta. Os valores médios de digestibilidade aparente da MS, MO, Proteína bruta (PB), fibra insolúvel em detergente neutro corrigido para cinzas e proteína(FDNcp) e nível dietético de NDT foram maiores para o resíduo folha. Constatou- se efeito de interação entre resíduo e o nível de substituição sobre as excreções urinárias de nitrogênio total (EUN), balanço nitrogenado aparente (BNA) e compostos nitrogenados microbianos (NMIC). Resíduos da produção de palmito oriundos da palmeira Real Australiana podem ser utilizados como alimentos volumosos na dieta de animais ruminantes, sendo destes, o resíduo folha e composta os que apresentaram melhores respostas nas características avaliadas.

The aim of this study was to evaluate the chemical composition, voluntary intake and apparent digestibility of the diets containing residue from palm heart of Australian Royal Palm (Archontophoenix alexandrae) to replace sugar cane on sheep. Twelve sheep were used with average live weight of 23,3 ± 2,8 Kg and they placed in metabolism cages and distributed in six latin square 2 x 2 in a factorial design 3 x 2 (three types of residue -sheet, bark and composed - and two levels of residue’s replacement, 5% and 15%). It was observed higher intake of dry matter (DM), organic matter (OM), nonfiber carbohydrates (NFC) by substitution of composed residue. The average values of apparent digestibility of DM, OM, crude protein (CP), neutral detergent fibre correct for ash and protein (NDFap) and total digestible nutrients (TDN) were higher for sheet residue. There was interaction between type of residue and level of residue’s replacement on the urinary excretion of total nitrogen (NUE), apparent nitrogen balance (BNA) and microbial nitrogen compost (NMIC). Residues from palm heart of Australian Royal Palm can be used as roughage in the ruminants’diet, and of these residues, the sheet and composed residue showed better response in the evaluated characteristics.

[Replacing of residue from production of palm Palm Royal Australian (Archontophoenix alexan- drae) in silage of sugar cane in diets of sheep]. / Substituição do resíduo da produção de palmito da Palmeira Real Australiana (Archontophoenix alexandrae) na silagem de cana-de-açúcar em dietas de ovinos.

The aim of this study was to evaluate the chemical composition, voluntary intake and apparent digestibility of the diets containing residue from palm heart of Australian Royal Palm (Archontophoenix alexandrae) to replace sugar cane on sheep. Twelve sheep were used with average live weight of 23.3 ± 2.8 Kg and they placed in metabolism cages and distributed in six latin square 2 x 2 in a factorial design 3 x 2 (three types of residue--sheet, bark and composed--and two levels of residue's replacement, 5% and 15%). It was observed higher intake of dry matter (DM), organic matter (OM), nonfiber carbohydrates (NFC) by substitution of composed residue. The average values of apparent digestibility of DM, OM, crude protein (CP), neutral detergent fibre correct for ash and protein (NDFap) and total digestible nutrients (TDN) were higher for sheet residue. There was interaction between type of residue and level of residue's replacement on the urinary excretion of total nitrogen (NUE), apparent nitrogen balance (BNA) and microbial nitrogen compost (NMIC). Residues from palm heart of Australian Royal Palm can be used as roughage in the ruminants'diet, and of these residues, the sheet and composed residue showed better response in the evaluated characteristics.

Expression profile of genes associated with mastitis in dairy cattle.

In order to characterize the expression of genes associated with immune response mechanisms to mastitis, we quantified the relative expression of the IL-2, IL-4, IL-6, IL-8, IL-10, IFN-γ and TNF- α genes in milk cells of healthy cows and cows with clinical mastitis. Total RNA was extracted from milk cells of six Black and White Holstein (BW) cows and six Gyr cows, including three animals with and three without mastitis per breed. Gene expression was analyzed by real-time PCR. IL-10 gene expression was higher in the group of BW and Gyr cows with mastitis compared to animals free of infection from both breeds (p < 0.05). It was also higher in BW Holstein animals with clinical mastitis (p < 0.001), but it was not significant when Gyr cows with and without mastitis were compared (0.05 < p < 0.10). Among healthy cows, BW Holstein animals tended to present a higher expression of all genes studied, with a significant difference for the IL-2 and IFN- γ genes (p < 0.001). For animals with mastitis no significant difference in gene expression was observed between the two breeds. These findings suggest that animals with mastitis develop a preferentially cell-mediated immune response. Further studies including larger samples are necessary to better characterize the gene expression profile in cows with mastitis.

Expression profile of genes associated with mastitis in dairy cattle

In order to characterize the expression of genes associated with immune response mechanisms to mastitis, we quantified the relative expression of the IL-2, IL-4, IL-6, IL-8, IL-10, IFN-γ and TNF-α genes in milk cells of healthy cows and cows with clinical mastitis. Total RNA was extracted from milk cells of six Black and White Holstein (BW) cows and six Gyr cows, including three animals with and three without mastitis per breed. Gene expression was analyzed by real-time PCR. IL-10 gene expression was higher in the group of BW and Gyr cows with mastitis compared to animals free of infection from both breeds (p < 0.05). It was also higher in BW Holstein animals with clinical mastitis (p < 0.001), but it was not significant when Gyr cows with and without mastitis were compared (0.05 < p < 0.10). Among healthy cows, BW Holstein animals tended to present a higher expression of all genes studied, with a significant difference for the IL-2 and IFN-γ genes (p < 0.001). For animals with mastitis no significant difference in gene expression was observed between the two breeds. These findings suggest that animals with mastitis develop a preferentially cell-mediated immune response. Further studies including larger samples are necessary to better characterize the gene expression profile in cows with mastitis.