Asymmetric physiological response of a reef-building coral to pulsed versus continuous addition of inorganic nutrients.

Coral reefs, especially those located near-shore, are increasingly exposed to anthropogenic, eutrophic conditions that are often chronic. Yet, corals under unperturbed conditions may frequently receive natural and usually temporary nutrient supplementation through biological sources such as fishes. We compared physiological parameters indicative of long- and short-term coral health (day and night calcification, fragment surface area, productivity, energy reserves, and tissue stoichiometry) under continuous and temporary nutrient enrichment. The symbiotic coral Acropora intermedia was grown for 7 weeks under continuously elevated (press) levels of ammonium (14 µmol L-1) and phosphate (10 µmol L-1) as separate and combined treatments, to discern the individual and interactive nutrient effects. Another treatment exposed A. intermedia twice-daily to an ammonium and phosphate pulse of the same concentrations as the press treatments to simulate natural biotic supplementation. Press exposure to elevated ammonium or phosphate produced mixed effects on physiological responses, with little interaction between the nutrients in the combined treatment. Overall, corals under press exposure transitioned resources away from calcification. However, exposure to nutrient pulses often enhanced physiological responses. Our findings indicate that while continuous nutrient enrichment may pose a threat to coral health, episodic nutrient pulses that resemble natural nutrient supplementation may significantly benefit coral health and physiology.

Effects of dietary organic acids on performance, cecal microbiota, and gut morphology in broilers.

Organic acids have exhibited great potential as an antibiotic replacement and as an additive work tremendously for health maintenance of broiler chicken. To explore more about organic acids, a total of 900 day-old broiler chicks (Cobb-500) were procured from a local hatchery and distributed into 9 treatment groups having 5 replicates of 20 birds each; duration of the biological trial was of 35 days. Group T1 served as control group without any dietary supplementation. Other groups T2 and T3 were boosted with different levels (125 g/ton and 250 g/ton) of enramycin (antibiotic), T4, T5, and T6 were supplemented with different levels (2 kg/ton, 3 kg/ton, and 4 kg/ton) of ammonium formate and ammonium propionate, and T7, T8, and T9 were fed with different levels (2 kg/ton, 3 kg/ton, and 4 kg/ton) of calcium formate and calcium propionate. The findings declared significant improvement (P < 0.05) in body weight gain and FCR in groups T3, T5, and T9 while feed intake was not affected. Carcass evaluation depicted significantly better (P < 0.05) dressed and eviscerated weight along with carcass yield (T5, T7, T8, T9). Broilers fed organic acid supplemented diet had significantly lower (P < 0.05) total bacterial count (T3, T5, T8, T9) and positively improved (P < 0.05) villi length (T5, T6, T9) as compared with control group. However, total protein, globulin, HDL, and LDL levels were determined to be non-significant (P > 0.05) among different organic acids treatments. Hence, organic acids can be utilized as a better replacement for antibiotics. Supplementation of organic acids at a dose rate of 3 kg/ton and 4 kg/ton is recommended for efficient performance of broilers.

Doxycycline and its quaternary ammonium derivative for adjuvant therapies of chondrosarcoma.

PURPOSE: This study was conducted during the development of innovative treatment targeting the microenvironment of chondrosarcoma. In this context, MMP inhibitors were conjugated with a quaternary ammonium (QA) function as a targeting ligand to proteoglycans of chondrosarcoma extracellular matrix. Here we report the proof of concept of this strategy applied to the MMP13 inhibitor, doxycycline (Dox). METHODS: A quaternary ammonium derivative of the MMP13 inhibitor doxycycline (QA-Dox) was synthesized, and its anticancer activity was evaluated in the Swarm rat chondrosarcoma (SRC) model compared with the parent drug doxycycline, in vitro and in vivo. In vivo, dox and QA-Dox efficiency was assessed at equimolar doses according to a q4dx4 schedule by monitoring tumour volume by MRI and PG-targeted scintigraphy. Molecular mechanism (MMP13 expression, proteoglycan level) and histology studies were performed on tumours. RESULTS: The link of QA targeting function to Dox maintained the MMP13 inhibitory activity in vitro. Interestingly, the bacteriostatic activity was lost. SRC cells incubated with both drugs were blocked in S and G2 M phases. Tumour growth inhibition (confirmed by histology) was observed for both Dox and QA-Dox. Undesirable blood effects (leukocyte decrease) were reduced when Dox was targeted to tumour tissue using the QA function. CONCLUSIONS: In the SRC model, the MMP13 inhibitor Dox and its QA derivative are promising as adjuvant therapies for chondrosarcoma management.