Project description:Purpose:To present the miRNA expression profiles in giant panda milk exosomes across five lactation stages (0, 3, 7, 15 and 30 days after birth), aiming to provide new information for investigations into the physiological functions of the giant panda milk Methods: Three females were sampled in all, and each individual were sampled over multiple lactations, including 0, 3, 7, 15 and 30 days after delivery. Breast milk samples (5-10 ml) were collected from each stages. Total RNA isolated from individuals in five lactation stages (0, 7, 15 and 30 days after delivery) were pooled in equal quantities for each stage Results: Here, we illustrated the species and expression characteristics of exosome-loaded miRNAs existing in giant panda breast milk during distinct lactation periods, and highlighted the enrichment of immune- and development-related endogenous miRNAs in colostral and mature giant panda milk, which are stable even in certain hash conditions, like low pH and high concentration of RNAase, by the protection of extracellular vesicles.These findings indicate that breast milk may allow dietary intake of maternal miRNAs by infants for the regulation of postnatal development. We also demonstrated that the exogenous plant miRNA from the primary food source of giant panda (bamboo) were detected in the exosomes of giant panda breast milk, which were predicted to be of regulatory role in basic cell metabolism and neuron development. This result suggested that the dietary plant miRNAs were able to be absorbed by host cell and then secreted to body fluids as potential cross-kingdom regulators. Conclusions: Exosomal miRNAs in the giant panda breast milk may be the crucial maternal regulators for the development of intrinsic ‘slink’ newborn cubs. Overall design: Three females were sampled in all, and each individual were sampled over multiple lactations, including 0, 3, 7, 15 and 30 days after delivery. Breast milk samples (5-10 ml) were collected from each stages. Total RNA isolated from individuals in five lactation stages (0, 7, 15 and 30 days after delivery) were pooled in equal quantities for each stage.
Project description:The iconic giant panda is an endangered species known worldwide for its peculiar dietary habits. While retaining the digestive system of a carnivore, the giant panda successfully moved into a diet almost exclusively based on bamboo. Digestion of lignocellulose is believed to be conducted solely by its gut microbiome, provided that no lignocellulose-degrading enzyme was found in the giant panda’s genome. Many reports focused on which lignocellulose component feeds the giant panda, while little effort was made to link the products of bamboo fermentation to the panda’s dietary choices. In the present study, fermentation of either green leaves or yellow pith was conducted in the laboratory using gut microbiomes derived from either green or yellow stools, respectively. Green leaves were fermented to ethanol, lactate and acetate, while yellow pith to lactate resembling, respectively, hetero/homo-fermentation patterns. Several microbial pathways (assessed by metaproteomics) related to hemicellulose rather than cellulose degradation. However, alpha-amylases (E.C. 18.104.22.168) from the giant panda itself were the most predominant enzyme (up to 60% of all metaproteins), indicating that they have a primary role in bamboo digestion. The distinct fermentation profiles resulting from digestion of selected portions of bamboo may be part of the feeding strategy of giant pandas.
Project description:Ursids (bears) in general, and giant pandas in particular, are highly altricial at birth. The components of bear milks and their changes with time may be uniquely adapted to nourish relatively immature neonates, protect them from pathogens, and support the maturation of neonatal digestive physiology. Serial milk samples collected from three giant pandas in early lactation were subjected to untargeted metabolite profiling and multivariate analysis. Changes in milk metabolites with time after birth were analysed by Principal Component Analysis, Hierarchical Cluster Analysis and further supported by Orthogonal Partial Least Square-Discriminant Analysis, revealing three phases of milk maturation: days 1–6 (Phase 1), days 7–20 (Phase 2), and beyond day 20 (Phase 3). While the compositions of Phase 1 milks were essentially indistinguishable among individuals, divergences emerged during the second week of lactation. OPLS regression analysis positioned against the growth rate of one cub tentatively inferred a correlation with changes in the abundance of a trisaccharide, isoglobotriose, previously observed to be a major oligosaccharide in ursid milks. Three artificial milk formulae used to feed giant panda cubs were also analysed, and were found to differ markedly in component content from natural panda milk. These findings have implications for the dependence of the ontogeny of all species of bears, and potentially other members of the Carnivora and beyond, on the complexity and sequential changes in maternal provision of micrometabolites in the immediate period after birth.