Chicken Hypothalamic and Ovarian DNA Methylome Alteration in Response to Forced Molting.

Epigenetic modifications play an important role in regulating animal adaptation to external stress. To explore how DNA methylation regulates the expression levels of related genes during forced molting (FM) of laying hens, the hypothalamus and ovary tissues were analyzed at five periods using Whole-Genome Bisulfite Sequencing. The results show that methylation levels fluctuated differently in the exon, intron, 5'UTR, 3'UTR, promoter, and intergenic regions of the genome during FM. In addition, 16 differentially methylated genes (DMGs) regulating cell aging, immunity, and development were identified in the two reversible processes of starvation and redevelopment during FM. Comparing DMGs with differentially expressed genes (DEGs) obtained in the same periods, five hypermethylated DMGs (DSTYK, NKTR, SMOC1, SCAMP3, and ATOH8) that inhibited the expression of DEGs were found. Therefore, DMGs epigenetically modify the DEGs during the FM process of chickens, leading to the rapid closure and restart of their reproductive function and a re-increase in the egg-laying rate. Therefore, this study further confirmed that epigenetic modifications could regulate gene expression during FM and provides theoretical support for the subsequent optimization of FM technology.

Transcriptomic Analysis of Laying Hens Revealed the Role of Aging-Related Genes during Forced Molting.

Molting in birds provides us with an ideal genetic model for understanding aging and rejuvenation since birds present younger characteristics for reproduction and appearance after molting. Forced molting (FM) by fasting in chickens causes aging of their reproductive system and then promotes cell redevelopment by providing water and feed again. To reveal the genetic mechanism of rejuvenation, we detected blood hormone indexes and gene expression levels in the hypothalamus and ovary of hens from five different periods during FM. Three hormones were identified as participating in FM. Furthermore, the variation trends of gene expression levels in the hypothalamus and ovary at five different stages were found to be basically similar using transcriptome analysis. Among them, 45 genes were found to regulate cell aging during fasting stress and 12 genes were found to promote cell development during the recovery period in the hypothalamus. In addition, five hub genes (INO80D, HELZ, AGO4, ROCK2, and RFX7) were identified by WGCNA. FM can restart the reproductive function of aged hens by regulating expression levels of genes associated with aging and development. Our study not only enriches the theoretical basis of FM but also provides insights for the study of antiaging in humans and the conception mechanism in elderly women.

Understanding Transcriptomic and Serological Differences between Forced Molting and Natural Molting in Laying Hens.

Molting is natural adaptation to climate change in all birds, including chickens. Forced molting (FM) can rejuvenate and reactivate the reproductive potential of aged hens, but the effect of natural molting (NM) on older chickens is not clear. To explore why FM has a dramatically different effect on chickens compared with NM, the transcriptome analyses of the hypothalamus and ovary in forced molted and natural molted hens at two periods with feathers fallen and regrown were performed. Additionally, each experimental chicken was tested for serological indices. The results of serological indices showed that growth hormone, thyroid stimulating hormone, and thyroxine levels were significantly higher (p < 0.05) in forced molted hens than in natural molted hens, and calcitonin concentrations were lower in the forced molted than in the natural molted hens. Furthermore, the transcriptomic analysis revealed a large number of genes related to disease resistance and anti-aging in the two different FM and NM periods. These regulatory genes and serological indices promote reproductive function during FM. This study systematically revealed the transcriptomic and serological differences between FM and NM, which could broaden our understanding of aging, rejuvenation, egg production, and welfare issues related to FM in chickens.

Improving effects of Epimedium flavonoids on the selected reproductive features in layer hens after forced molting.

In the present study, for the purpose of investigating the effects of the total flavonoids of Epimedium (TFE) in regard to preventing the development of atrophied oviducts and follicles induced by forced molting, 300-day-old Hy-Line Brown layer hens were divided into 3 study groups as follows: the control (CON) group was the normal group, without forced molting and TFE treatments; the TFE1 group was treated by adding a 1‰ TFE treatment after forced molting; and the TFE0 group was not treated by TFE after forced molting. During this study's experimental process, the egg production rates were recorded each day. In addition, the hens were randomly chosen to be weighed every 4 D and also randomly selected to be sacrificed every 7 D. Then, sample tissues of albumen-secreting part and uterus from the fallopian tube of the layer hens were collected for PCR and hematoxylin-eosin staining tests. The results showed that the body weights, number of follicles, and weights and sizes of the fallopian tube for the TFE1 and TFE0 groups were significantly reduced when compared with those of the control group on the 15th D of the experiment. Furthermore, at the end of study, it was found that the egg production rates, weights of the fallopian tube, and ovarian follicles of TFE1 had recovered to normal levels. At the same time, the serum estrogen and the expressions of the progesterone receptor and estrogen receptor mRNA in fallopian tube were higher than those observed for the TFE0 group. The results of this study provided valuable evidence that TFE could improve the development of atrophied oviducts and increase the egg laying rates, thereby making it a potential multicomponent natural drug for egg production in the future.

Analysis of excreta bacterial community after forced molting in aged laying hens.

OBJECTIVE: As laying hens become aged, laying performance and egg quality are generally impaired. One of the practical methods to rejuvenate production and egg quality of aged laying hens with decreasing productivity is a forced molting. However, the changes in intestinal microbiota after forced molting of aged hens are not clearly known. The aim of the present study was to analyze the changes in excreta bacterial communities after forced molting of aged laying hens. METHODS: A total of one hundred 66-wk-old Hy-Line Brown laying hens were induced to molt by a 2-d water removal and an 11-d fasting until egg production completely ceased. The excreta samples of 16 hens with similar body weight were collected before and immediately after molting. Excreta bacterial communities were analyzed by high-throughput sequencing of bacterial 16S rRNA genes. RESULTS: Bacteroidetes, Firmicutes, and Proteobacteria were the three major bacterial phyla in pre-molting and immediate post-molting hens, accounting for more than 98.0%. Lactobacillus genus had relatively high abundance in both group, but decreased by molting (62.3% in pre-molting and 24.9% in post-molting hens). Moreover, pathogenic bacteria such as Enterococcus cecorum and Escherichia coli were more abundant in immediate post-molting hens than in pre-molting hens. Forced molting influenced the alpha diversity, with higher Chao1 (p = 0.012), phylogenetic diversity whole tree (p = 0.014), observed operational taxonomic unit indices (p = 0.006), and Simpson indices (p<0.001), which indicated that forced molting increased excreta bacterial richness of aged laying hens. CONCLUSION: This study improves the current knowledge of bacterial community alterations in the excreta by forced molting in aged laying hens, which can provide increasing opportunity to develop novel dietary and management skills for improving the gastrointestinal health of aged laying hens after molting.

Torta de mamona não destoxificada na indução da muda forçada em poedeiras comerciais / Non-detoxified castor bean for molt induction in laying hens

Avaliou-se o uso de dietas com diferentes porcentagens de torta de mamona não destoxificada (TM) na indução da muda forçada, sendo utilizadas 120 poedeiras Lohman LSL de 81 semanas, distribuídas ao acaso em quatro tratamentos, com cinco repetições de seis aves. Um dos tratamentos consistiu na indução da muda pelo método do jejum por 11 dias, e os demais no uso de dietas de muda, compostas pela mistura de dieta de postura e TM nas quantidades de 20, 30 e 40 por cento, por até 21 dias ou até quando as aves atingissem 23 por cento de perda do peso. Diferenças significativas foram observadas nos eritrócitos, no hematócrito, na concentração média de hemoglobina globular, na proteína total do plasma, nos leucócitos e na alanina aminotransferase, medidos durante a indução da muda, bem como no desempenho das aves após a muda, no que diz respeito ao consumo de ração, à porcentagem de postura, ao peso do ovo, à massa do ovo e à conversão alimentar. A qualidade dos ovos não variou estatisticamente entre os métodos avaliados. A utilização da dieta de muda forçada contendo 40 por cento de TM promoveu resultados semelhantes aos obtidos com o método do jejum, tanto para consumo de ração, porcentagem de postura, peso do ovo, massa do ovo, e conversão alimentar, como inerentes à qualidade dos ovos, quanto para densidade específica, unidade Haugh, porcentagens de gema, casca e albúmen. No entanto, menores alterações nos valores de eritrócitos, hematócrito e alanina aminotransferase foram observadas nesse método supracitado. O uso da dieta de muda contendo 40 por cento de TM mostrou-se uma alternativa viável ao uso do método do jejum...

We evaluated diets with different percentages of non-detoxified castor bean (TM) in the induction of molt, with 120 Lohman LSL hens at 81 weeks of age being used, randomly allotted to four treatments with five replicates of six birds each. One of the treatments consisted in the induction of changes by the method of fasting for 11 days, and the others used diet switches, composed by mixing posture and TM diet in the amounts of 20, 30 and 40 percent for up to 21 days or until when the birds reach 23 percent weight loss. Significant differences were observed in erythrocytes, hematocrit, mean concentration of corpuscular hemoglobin, total protein in plasma, leukocytes and alanine aminotransferase measured during induction of changes, and the performance of birds after moulting, such as feed intake, percentage of laying, egg weight, egg mass and feed conversion. The quality of the eggs did not vary significantly among the methods evaluated. The use of forced molting diet containing 40 percent of TM promoted results similar to those obtained with the method of fasting, both feed intake and the percentage of egg, egg weight, egg mass, and feed conversion, as inherent quality of eggs, as the specific gravity, Haugh unit, yolk percentage, albumen and shell. However, minor changes in the values of erythrocytes, hematocrit and alanine aminotransferase were observed in the method above. The use of diets containing 40 percent change TM proved to be a viable alternative to the use of the fasting method...

Efectos en el tracto reproductivo, digestivo y pérdida de pesocorporal del ave semipesada sometida a descanso ovárico / Efeitos no trato reprodutivo, digestivo e perda do peso de aves semi-pesadossubmetidas a descanso ovárico / The effects on the reproductive and digestive tract and loss of body weight of the Brown egg layers submitted to ovarian rest

Esta investigación evaluó la aplicación del descanso ovárico (DO) en aves semipesadas y el efecto quetienen la edad y la duración del ayuno sobre el tracto reproductivo y gastrointestinal. Se utilizaron 840ponedoras de la línea Hy-Line Brown® con 64 semanas de edad, se evaluaron tres edades de inducciónal DO (65, 70 y 75 semanas) y tres períodos de ayuno (cinco, diez y quince días), en un modelo estadísticocompletamente aleatorizado, anidado, efecto fijo y balanceado. Se sacrificaron aves para evaluar el pesocorporal, peso del tracto digestivo, peso del tracto reproductivo (ovario y oviducto), porcentaje de folículoscon diámetro igual o superior a diez mm (LYF) y el porcentaje de pérdida de peso del ave. El modelo fuesignificativo (p<0.05) para todas las variables evaluadas; la edad presentó efecto significativo (p<0.05) enel peso del ovario y el porcentaje de folículos (LYF), mientras que la duración del ayuno anidado en laedad presentó efecto significativo (p<0.05) en todas las variables, lo que indica un mayor efecto del períodode ayuno en contraste con la edad de aplicación del DO sobre las variables evaluadas. El peso del ovario(edad 65:15.87 ±15.11; edad 70: 7.92 ± 5.46; y edad 75: 7.54 ± 4.96) y porcentaje de folículos (LYF) (edad65: 43.75 ± 21.54; la edad 70 18.05 ± 8.72 y edad 75: 8.33 ± 6.85), mostraron tendencia en la disminucióna medida que aumenta la edad, comportamiento que está asociado con la disminución gradual del númerode folículos y la ampliación del tiempo entre la maduración de una onda folicular y la siguiente normaldel ave a medida que envejece (Kim y Donalson, 2000; North y Bell, 1990). Los porcentajes de pérdida de peso (edad 65: 24.24 ± 8.53%; edad 70: 20.91 ± 5.50% y edad 75: 20.88 ± 7.15%), fueron menores encomparación con los reportes en líneas livianas, posiblemente debido al contenido de reservas lipídicas,lo que ofrece al ave semipesada la capacidad de tolerar el ayuno.

The effects on the reproductive and digestive tract and loss of body weight of the Brown egg layerssubmitted to ovarian rest. This research evaluated the application of the ovarian rest (OR) on brown egglayers and the effect the age and duration of feed withdrawal have over the reproductive and gastrointestinaltract. 840 Hy-Line Brown ® layers were used at 64 weeks of age in which three ages of induction to theOR (65.70 and 75 weeks) and three feed withdrawal periods (five, ten and fifteen days) in a completelyrandomized statistical model, nested, of balanced and fixed effect. Sacrifices were carried out in order toevaluate body weight, weight of the digestive and reproductive tract (ovary and oviduct), follicle percentagewith a diameter equal to or higher than ten mm (LYF) and the percentage of the bird’s weight loss. Themodel was significant (p<0.05) for all the variables evaluated; the age presented a significant effect(p<0.05) over the ovary weight and the follicle percentage (LYF), while the duration of the feed withdrawalrelated to the age had a significant effect (p<0.05) on all the variables, which indicates a greater effect ofthe feed withdrawal period contrasted to the age of the application of the OR upon the variables evaluated.The ovary’s weight (age 65:15.87 to ± 15.11; age 70: 7.92b ± 5.46; and age 75: 7.54b ± 4.96) and thefollicle percentage (65: 43.75 to ± 21.54; age 70 18.05b ± 8.72 and age 75: 8.33b ± 6.85) showed a loweringtendency as the age increased. This type of behavior is associated with the gradual decrease in the numberof follicles and the extended time between the maturation of one follicular wave and the next as the layerages (Kim, Donalson, 2006; North, Bell, 1990). The weight loss percentages (age 65: 24.24 ± 8.53%; age70: 20.91 ± 5.50% and age 75: 20.88 ± 7.15%) were low compared to the reports on white egg layers,possibly due to the content of lipidic reserves which offers the brown egg...

Foi avaliado o descanso ovárico (DO) em galinhas semipesadas e o efeito da idade e a duração do jejumsobre o trato reprodutivo e gastrointestinal. Foram utilizadas 840 galinhas poedoras da linha Hy-LineBrown® com 64 semanas de idade, foram avaliadas três idades de indução ao DO (65, 70 e 75 semanas) etrês períodos de jejum (cinco, dez e quinze dias), utilizando um modelo desenho completamente aleatório,aninhado , efeito fixo e balanceado. As aves foram sacrificadas para avaliar o peso corporal, peso do tratodigestivo, peso do trato reprodutivo (ovário e oviduto), porcentagem de folículos com diâmetro igual ousuperior a dez mm (LYF) e a porcentagem da perdida de peso da ave. O modelo foi significativo (p<0.05)para todas as variáveis avaliadas; a idade foi significativa (p<0.05) no peso do ovário e a LYF e a duraçãodo jejum aninhado na idade apresentou efeito significativo (p<0.05) em todas as variáveis, o que indicouum maior efeito do período de jejum do que a idade sobre as variáveis avaliadas. O peso do ovário (idade65:15.87 ±15.11; idade 70: 7.92 ± 5.46; e idade 75: 7.54 ± 4.96) e percentagem de folículos (idade 65: 43.75± 21.54; idade: 70: 18.05 ± 8.72 e idade 75: 8.33 ± 6.85), mostraram tendência na diminuição à medidaque aumenta a idade. As percentagens de perda de peso (idade 65: 24.24 ± 8.53%; idade 70: 20.91 ± 5.50%e idade 75: 20.88 ± 7.15%) e as três idades apresentaram uma relação direta entre a duração dos períodosde jejum e o efeito na atrofia reprodutiva e perda de peso, permitindo determinar que não é necessáriosubmeter a jejuns superiores a dez dias.