Two studies were conducted to evaluate the effects of organic acid (OA) supplementation in a highly digestible (Exp. 1) or a less digestible diet (Exp. 2) on the growth performance and intestinal health of weaned pigs. In Exp. 1, a total of 240 pigs weaned at day 21 were assigned to one of five dietary treatments: negative control (NC) (basal diet, 3,000 ppm zinc oxide (ZnO) in the first 2 wk only); positive control (PC) (NC plus 10 mg/kg zinc bacitracin, 5 mg/kg colistin sulfate, and 5 mg/kg olaquindox); OA1 (NC plus a 0.2% blend of encapsulated butyrate, medium-chain fatty acids [MCFA], OA, and phenolics); OA2 (NC plus 0.3% blend of free and buffered short-chain fatty acids [SCFA] combined with MCFA); and OA1 plus OA2 (NC plus 0.2% OA1 plus 0.3% OA2) for 49 d. All treatments in Exp. 1 used the same highly digestible basal diet. At day 28, eight pigs from each group were sacrificed, to collect intestinal and digesta samples for biochemical analysis. Growth performance and intestinal morphology were not affected by the treatments. However, pigs subjected to the OA2 treatment had lower levels of Escherichia coli (P < 0.05) in the colon. In addition, the OA1 and OA2 treatments, and their combination resulted in higher concentrations of acetate and propionic acid in the cecum and colon (P < 0.01) in comparison to the NC. A less digestible diet without high levels of ZnO was used in Exp. 2. A similar design was used with the exception of the replacement of OA2 with another OA blend (OA3, a blend of free and buffered OA). In comparison to the NC, supplementation with OA1 and OA3 in a less digestible diet improved the ADG and the F:G ratio in the seventh week post-weaning (P < 0.01); reduced the diarrhea index of pigs during the first 3 wk post-weaning (P < 0.05); increased the ileal villus height (P < 0.05), and acetic and propionic acid concentrations in colon contents (P < 0.05). Moreover, the genus Prevotella was increased in the colon and the microbial community structure was significantly altered in the OA1 + OA3 treatment. The present research indicated that dietary supplementation with OA improved intestinal health. The OA blends showed a similar growth-promoting effect as antibiotics in the less digestible diet, to which high levels of ZnO had not been added.

In this study, nitrated bacterial cellulose (NBC) energetic binder was introduced to prepare NBC-based nanocomposite energetic materials (nEMs) through a combined simple and safe sol−gel method and the freeze-drying technology. A series of analytical and test methods were systematically conducted to characterize the structure, composition, thermal properties, and safety performance of the materials. The results indicated that the particles of nitramine explosives were dispersed and embedded homogeneously in the three-dimensional (3D) porous cross-linked construction of the NBC gel matrix; the crystal growth of the explosive particles was restricted, which led to nanometer-scale composites. The thermal analysis demonstrated that the peak temperature of the composite (e.g., NBC/CL-20: 224.8 °C) was reduced and produced substantial heat release (e.g., NBC/CL-20: 3346 J•g −1 ) during the process of decomposition. In addition, the mechanism of thermal decomposition was probed, and cyclic catalytic decomposition between the NBC gel and explosives may exist. The sensitivity decreased visibly because of the existence of the cross-linked structure of the gel matrix, which could act as a buffer system to mitigate the release stimulated from the surroundings. Accordingly, this investigation may provide the promising potential for NBCbased energetic composites used in explosives and propellants in the military, and further promote the methodology for manufacturing energetic nanocomposites.

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Formation and expansion of cracks in propellant would induce debonding at interface between different constituents, and may even cause explosion of the propellant during launch. One way to prohibit the...