BackgroundAnimal domestication has been extensively studied, but the process of feralization remains poorly understood.ResultsHere, we performed whole-genome sequencing of 99 sheep and identified a primary genetic divergence between 2 heterogeneous populations in the Tibetan Plateau, including 1 semi-feral lineage. Selective sweep and candidate gene analysis revealed local adaptations of these sheep associated with sensory perception, muscle strength, eating habit, mating process, and aggressive behavior. In particular, a horn-related gene, RXFP2, showed signs of rapid evolution specifically in the semi-feral breeds. A unique haplotype and repressed horn-related tissue expression of RXFP2 were correlated with higher horn length, as well as spiral and horizontally extended horn shape.ConclusionsSemi-feralization has an extensive impact on diverse phenotypic traits of sheep. By acquiring features like those of their wild ancestors, semi-feral sheep were able to regain fitness while in frequent contact with wild surroundings and rare human interventions. This study provides a new insight into the evolution of domestic animals when human interventions are no longer dominant.

Background Sheep have developed the ability to store fat in their tails, which is a unique way of reserving energy to survive a harsh environment. However, the mechanism underlying this adaptive trait remains largely unsolved. Results In the present study, we provide evidence for the genetic determinants of fat tails, based on whole genome sequences of 89 individual sheep. A genome-wide scan of selective sweep identified several candidate loci including a region at chromosome 13, a haplotype of which underwent rapid evolution and spread through fat-tailed populations in China and the Middle East. Sequence analysis revealed an inter-genic origin of this locus, which later became a hotspot of ruminant-specific retro-transposon named BovB. Additionally, the candidate locus was validated based on a fat- and thin-tailed cross population. The expression of an upstream gene BMP2 was differentially regulated between fat-tailed and thin-tailed individuals in tail adipose and several other tissue types. Conclusions Our findings suggest the fixation of fat tails in domestic sheep is caused by a selective sweep near a retro-transposable hotspot at chromosome 13, the diversity of which specifically affects the expression of BMP2 . The present study has shed light onto the understanding of fat metabolism. Electronic supplementary material The online version of this article (10.1186/s12864-019-5620-6) contains supplementary material, which is available to authorized users.

A yield prediction model for Italian ryegrass (IRG) was constructed based on climatic data by locations in South Korea using a general linear model. The sample size of the final dataset was 312 during 25 years. The forage crop and climatic data were collected from the reports of two national research projects on forage crops and Korean meteorological administration, respectively. Five optimal climatic variables were selected through the stepwise multiple regression analysis with dry matter yield (DMY) as the response variable. Subsequently, three climatic variables were selected after considering the interpretability of the five variables. The three selected climatic variables were spring accumulated temperature, mean temperature in January and spring rainfall days. Then, the yield prediction model was constructed based on these three climatic variables using general linear model with the cultivated locations as dummy variables. The model constructed in this research could explain 73.6% of variation in DMY of IRG. The goodness‐of‐fit of the model was tested through residual diagnostics and 10‐fold cross‐validation. For climatic variables, the high partial eta squared value of spring accumulated temperature and spring rainfall may reflect the growth characteristics that spring is the main growing period for IRG and IRG has strong waterlogging tolerance and weak drought tolerance. The results may also support the possibility to sow IRG in the subsequent spring if autumnal seeding was missed in South Korea.

Broiler carcass skin color is important in China, the United States, Mexico, and other countries. The present study evaluated the use of natural and synthetic pigments in broiler diets at different commercial levels. The experiment included 288 fifty-day-old Da-Ma-Hua birds, divided into 6 treatments. Birds in 4 treatments were fed a basal diet consisting of 2, 3, 4, or 5% okra [Abelmoschus esculentus (L.) Moench Meth., also known as abelmosk or ram-horn bean] meal, respectively. Birds in another treatment received a basal diet without okra, and birds in a sixth treatment were fed a blend of 25 g/metric ton of 10% canthaxanthin and 50 g/metric ton of 10% carotenoic acid, β-apo-8′-ethylesters. Each treatment consisted of 3 replicates of 16 birds each. The experiment lasted 6 wk. Skin color was measured with a Kemin color fan after slaughter and chilling at wk 2, 3, 4, 5, and 6 of treatment. Pigmentation of the chicken skin and abdominal fat were significantly improved (P < 0.05) in the 4 and 5% okra treatments. The pigmentation effect reached a satisfactory level after 4 wk of treatment. The rank of pigmentation in different parts of the body of a bird was shank > breast > abdomen > back. The addition of okra meal had no significant influence on daily gain or the feed-to-gain ratio (P > 0.05). This study shows that xanthophyll-rich okra meal can be used as a natural pigment source in poultry feed, which may allow pigment use and feed costs to be reduced.

Background Colonization of intestinal microbiota in ruminant during the early life is important to host health, metabolism and immunity. Accumulating evidence revealed the ameliorative effect of milk replacer administration in the gut microbial development of early-weaned ruminants. Yimeng black goats (YBGs) inhabiting Shandong, China show a complex intestinal microbial ecosystem, but studies of their gut microbiota are still insufficient to report. Here, this study was performed to investigate how the gut microbiota develops in weaned YBGs with the effect of age and milk replacer. Results Results indicated that both age and milk replacer were important factors to change the gut microbiota of YBGs. Although the alpha diversity of gut microbiota did not change with the age of YBGs, the taxonomic compositions significantly changed. The relative abundance of some beneficial bacteria such as Lachnospiraceae, Ruminococcaceae, Ruminiclostridium, Eubacterium and Barnesiella significantly decreased and subsequently increase with age, which contributes to maintain the stability of intestinal environment and realize the diversity of intestinal functions. The relative abundance of Porphyromonas, Brevundimonas, Flavobacterium, Stenotrophomonas, Propionibacterium, Acinetobacter, Enterococcus and Clostridium belong to pathogenic bacteria in milk replacer-treated YBGs was significantly decreased. Additionally, some beneficial bacteria such as Ruminococcus, Ruminococcaceae, Christensenellaceae and Ruminiclostridium also display a trend of decreasing first followed by gradually increasing. Conclusions This study first revealed the gut bacterial community alterations in YBGs with the effect of age and milk replacer. This study also characterized the gut microbial distribution in YBGs with different ages and provided better insight into microbial population structure and diversity of YBGs. Moreover, milk replacer may serve as a good applicant for improving gut microbial development in early-weaned YBGs.