Macromineral requirements of Dorper×thin-tailed Han crossbred female lambs

A comparative slaughter trial was conducted to determine the net mineral requirements for maintenance and growth of Dorper crossbred female lambs raised from 20 to 35 kg of body weight（BW）.Thirty-five Dorper×thin-tailed Han crossbred female lambs of（20.3±1.14） kg BW were used： 7 lambs were randomly chosen and slaughtered at the beginning of the experiment as the baseline group for measuring the initial body composition; another 7 lambs were randomly chosen and offered a pelleted mixed diet ad libitum and slaughtered at（27.0±0.73） kg BW; the remaining 21 lambs were randomly divided into 3 groups of 7 animals each and subjected to the same diet either ad l ibitum or at 70 or 40% of ad libitum intake.The 21 lambs were fed in 7 slaughter groups, with each group consisting of one lamb from each treatment（ad libitum, 70 or 40% of ad libitum intake）.The 3 groups were slaughtered when the sheep fed ad libitum attained（33.8±0.52） kg of BW.The body composition of five minerals（Ca, P, Na, K, and Mg） was determined.The net mineral requirements for maintenance were 35.01, 25.18, 9.30, 31.35, and 2.03 mg kg–1 empty BW（EBW） for Ca, P, Na, K, and Mg, respectively, and the net growth requirement per kg of EBW gain ranged from 9.73 to 8.87 g of Ca, 5.83 to 5.27 g of P, 1.73 to 1.63 g of Na, 3.73 to 4.08 g of K, and 0.26 to 0.25 g of Mg for Dorper crossbred lambs in China, respectively.The estimates of mineral requirements with Dorper crossbred lambs in the current study were not consistent with the recommendations from previous studies.

LRP6 in mesenchymal stem cells is required for bone formation during bone growth and bone remodeling

Lipoprotein receptor-related protein 6 （LRP6） plays a critical role in skeletal development and homeostasis in adults. However, the role of LRP6 in mesenchymal stem cells （MSCs）, skeletal stem cells that give rise to osteoblastic lineage, is unknown. In this study, we generated mice lacking LRP6 expression specifically in nestin＋ MSCs by crossing nestin-Cre mice with LRP6 flox mice and investigated the functional changes of bone marrow MSCs and skeletal alterations. Mice with LRP6 deletion in nestin＋ cells demonstrated reductions in body weight and body length at I and 3 months of age. Bone architecture measured by microCT （uCT） showed a significant reduction in bone mass in both trabecular and cortical bone of homozygous and heterozygous LRP6 mutant mice. A dramatic reduction in the numbers of osteoblasts but much less significant reduction in the numbers of osteoclasts was observed in the mutant mice. Osterix＋ osteoprogenitors and osteocalcin＋ osteoblasts significantly reduced at the secondary spongiosa area, but only moderately decreased at the primary spongiosa area in mutant mice. Bone marrow MSCs from the mutant mice showed decreased colony forming, cell viability and cell proliferation. Thus, LRP6 in bone marrow MSCs is essential for their survival and proliferation, and therefore, is a key positive regulator for bone formation during skeletal growth and remodeling.

SDG721 and SDG705 are required for rice growth

Summary H3K4me3 plays important roles in development, transcription, and environmental responses. Here, we report that SDG721 （SET-domain group protein 721） and SDG705 are involved in regulating rice development. SDG721 and SDG705 encode TRITHORAX-Iike proteins, which appear to modulate H3K4 methylation levels. Loss of SDG721 and SDG705 function resulted in GA-deficient phenotypes, including semi-dwarfism, reduced cell length, and reduced panicle branching.