Revisão sistemática do uso de fitobióticos na nutrição de frangos de corte

The objective of this study was to conduct a systematic review of the literature on the use of phytogenics in broiler nutrition. A bibliographic survey was conducted for the years between 2009 and 2019, using the keywords “eubiotics,” “phytobiotics,” “essential oils,” “phytogenic extracts,” and corresponding words associated with the terms “broiler” and “poultry.” The selected articles were grouped into the categories: animal performance, histomorphology of the intestinal wall, biochemical profile, carcass characteristics, and the effect on bacteria found in the intestine. After comparisons of several parameters on the use or non-use of phytogenics, it was found that replacing antibiotics with phytogenics contributes positively to performance, the histomorphology of the intestinal wall, the biochemical profile, carcass characteristics, and the number of bacteria found in the gut. In conclusion, based on several studies found in the literature, replacing antibiotics with phytogenic additives in broiler nutrition may be viable due to their lower residual impact on the final product, in addition to their positive effect on the parameters of animal production.Objetivou-se realizar uma revisão sistemática da literatura sobre o uso de fitogênicos na nutrição de frangos de corte. Foi realizado levantamento bibliográfico do período de 2009 a 2019. Foram utilizadas as palavras-chave utilizadas foram “eubióticos”, “fitobióticos”, “óleos essenciais” e “extratos fitogênicos” e suas correspondentes em inglês, “eubiotics” e “phytobiotics”, “essential oils” e “phytogenic extracts” associada a palavra “frango de corte”, e “poultry” em inglês. Os artigos selecionados foram agrupados nas categorias: desempenho zootécnico, histomorfologia da parede intestinal, perfil bioquímico do sangue, característica de carcaça e o efeito nas bactérias encontradas no intestino. Após comparações de diversos parâmetros sobre o uso ou não uso de fitogênicos, percebeu- se que a substituição dos antibióticos pelos fitogênicos pode ser considerado positiva para o desempenho, histomorfologia da parede intestinal, perfil bioquímico do sangue, característica de carcaça e número de bactérias encontradas no intestino. Sendo assim, foi concluído com base nos diversos trabalhos encontrados na literatura que a substituição dos antibióticos pelos aditivos fitogênicos na nutrição de frangos de corte pode ser viável, devido ao seu menor impacto residual no produto final, além de influenciar positivamente nos parâmetros de produção animal

Carcass characteristics of Peloco naturalized chicken compared to free‑range broiler lineages

O objetivo deste trabalho foi avaliar a diversidade fenotípica de uma população de galinhas Peloco e compará‑la a três linhagens comerciais de frango de corte do tipo caipira. Avaliações foram feitas quanto a características de: peso de carcaça, peito, coxa e sobrecoxa; altura, largura e comprimento do peito; e comprimento da coxa e da sobrecoxa. Os dados foram submetidos às análises de variáveis canônicas e à análise discriminante independente do tamanho (ADIT). Os resíduos da ADIT foram utilizados na análise de agrupamento pelos métodos de Tocher e UPGMA. As duas primeiras variáveis canônicas foram suficientes para explicar 94,66% da variação total entre os fenótipos. O peso da carcaça teve a maior contribuição para a variação (59,91%) entre os grupos de aves, seguido de peso da coxa (12,63%) e largura do peito (11,75%). Ambos os métodos de agrupamento resultaram na formação de dois grupos: um de linhagens comerciais e outro da raça Peloco. O isolamento da Peloco é consequência da ausência de seleção para as características estudadas. Além disso, a presença de variabilidade dentro da raça Peloco mostra a existência de animais com maior potencial quanto ao peso de carcaça, o que possibilita o melhoramento da raça.The objective of this work was to evaluate the phenotypic diversity of a Peloco chicken population and to compare it with three free‑range broiler commercial lineages. Evaluations were done for the following characteristics: the weights of carcass, breast, drumstick, and thigh; the height, width, and length of breast; and the lengths of drumstick and thigh. Data were submitted to canonic variable analyses and to size‑independent discriminant analysis (ADIT). The ADIT residues were used in Tocher´s grouping analysis and in UPGMA method. The first two canonic variables were sufficient to explain 94.66% of the total variation among phenotypes. Carcass weight had the greatest contribution for the variation (59.91%) among the bird groups, followed by drumstick weight (12.63%) and breast width (11.75%). Both grouping methods resulted in the formation of two groups, one of the commercial lineages, and other of the Peloco breed. Peloco isolation is a consequence of the selection absence for the studied characteristics. In addition, the presence of variability in Peloco breed shows the existence of animals with a greater potential for carcass weight, which makes it possible the improvement of this breed

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Influence of heat stress on reference genes stability in heart and liver of two chickens genotypes.

INTRODUCTION:Real-time polymerase chain reaction (RT-qPCR) is an important tool for analyzing gene expression. However, before analyzing the expression of target genes, it is crucial to normalize the reference genes, in order to find the most stable gene to be used as an endogenous control. A gene that remains stable in all samples under different treatments is considered a suitable normalizer. In this sense, we aimed to identify stable reference genes for normalization of target genes in the heart and liver tissues from two genetically divergent groups of chickens (Cobb 500® commercial line and Peloco backyard chickens) under comfort and acute heat stress environmental conditions. Eight reference genes (ACTB, HPRT1, RPL5, EEF1, MRPS27, MRPS30, TFRC and LDHA) were analyzed for expression stability. The samples were obtained from 24 chickens, 12 from the backyard Peloco and 12 from the Cobb 500® line, exposed to two environmental conditions (comfort and heat stress). Comfort temperature was 23°C and heat stress temperature was 39.5°C for one hour. Subsequently, the animals were euthanized, and heart and liver tissue fragments were collected for RNA extraction and amplification. To determine the stability rate of gene expression, three different statistical algorithms were applied: BestKeeper, geNorm and NormFinder, and to obtain an aggregated stability list, the RankAgregg package of R software was used. RESULTS:The most stable genes using BestKeeper tool, including the two factors (genetic group and environmental condition), were LDHA, RPL5 and MRPS27 for heart tissue, and TFRC, RPL5 and EEF1 for liver tissue. Applying geNorm algorithm, the best reference genes were RPL5, EEF1 and MRPS30 for heart tissue and LDHA, EEF1 and RPL5 for liver. Using the NormFinder algorithm, the best normalizer genes were EEF1, RPL5 and LDHA in heart, and EEF1, RPL5 and ACTB in liver tissue. In the overall ranking obtained by RankAggreg package, considering the three algorithms, the RPL5, EEF1 and LDHA genes were the most stable for heart tissue, whereas RPL5, EEF1 and ACTB were the most stable for liver tissue. CONCLUSION:According to the RankAggreg tool classification based on the three different algorithms (BestKeeper, geNorm and NormFinder), the most stable genes were RPL5, EEF1 and LDHA for heart tissue and RPL5, EEF1 and ACTB for liver tissue of chickens subjected to comfort and acute heat stress environmental conditions. However, the best reference genes may vary depending on the experimental conditions of each study, such as different breeds, environmental stressors, and tissues analyzed. Therefore, the need to perform priori studies to assay the best reference genes at the outset of each study is emphasized

Influence of heat stress, sex and genetic groups on reference genes stability in muscle tissue of chicken

<div><p>Quantitative RT-PCR is an important technique for assessing gene expression. However, a proper normalization of reference genes prior to expression analyses of target genes is necessary. The best normalizer is that gene which remains stable in all samples from different treatments. The aim of this study was to identify stable reference genes for normalization of target genes in muscle tissue from three genetically divergent chickens groups (Peloco, Cobb 500^® and Caneluda) under environmental (heat stress and comfort) and sex influence. Expressions of ten reference genes were tested for stability in breast muscular tissue (<i>Pectoralis major</i> muscle). Samples were obtained from 36 males and females of two backyard breeds (Caneluda and Peloco) and one commercial line (Cobb 500^®) under two environments. The heat stress and comfort temperature were 39 and 23°C, respectively. Animals were housed in the Animal Science Department at <i>Universidade Estadual do Sudoeste da Bahia</i>. We analyzed the expression data by four statistical tools (SLqPCR, NormFinder, Bestkeeper and Comparative CT). According to these tools, genes stability varied according to sex, genetic group and environment, however, some genes remained stable in all analyzes. There was no difference between the most stable genes for sex effect, being <i>MRPS27</i> more stable for both males and females. In general, <i>MRPS27</i> was the most stable gene. Within the three genetic groups, the most stable genes were <i>RPL5</i>, <i>HMBS</i> and <i>EEF1</i> to Cobb 500^®, Peloco and Caneluda, respectively. Within the environment, the most stable gene under comfort and heat stress conditions was <i>HMBS</i> and <i>MRPS27</i>, respectively. BestKeeper and Comparative Ct were less correlated (28%) and SLqPCR and NormFinder were the most correlated (98%). <i>MRPS27</i>, <i>RPL5</i> and <i>MRPS30</i> genes were considered stable according the overall ranking and can be used as normalizer of relative expression of target genes in muscle tissue of chickens under heat stress.</p></div

Initial feed used in the production of chicks up to 30 days of age (ROSTAGNO, GOMES, 2011).

<p>Initial feed used in the production of chicks up to 30 days of age (ROSTAGNO, GOMES, 2011).</p

Ranking with stability values for each treatment (genetic group, sex, and environment) in chicken obtained from BestKeeper tool.

<p>Values into the parenthesis refer to ranking by Bestkeeper to each treatment. Values on the last column refer to the ranking position by RankAggreg package among all the treatments.</p