Optimization of weaning strategy in the climbing perch (Anabas testudineus, Bloch 1792) larvae on growth, survival, digestive, metabolic and stress responses.

A 30-day experiment was carried out to know responses of different weaning approaches to the growth and survival of Anabas testudineus larvae. A total of 10800 larvae (Avg. weight 0.016 ± 0.03 mg; 3DPH) were randomly distributed in nine treatments (triplicates), including two controls. The strategies are as follows: C1 (Control I): feeding with live food (LF) for 30 days and C2 (Control II): feeding with microparticulate diet (MPD) for 30 days; T1: LF for 5 days and MPD for next 25 days; T2: LF for 10 days and MPD for next 20 days; T3: LF for 15 days and MPD for next 15 day; T4: LF for 20 days and MPD for next 10 days; T5: LF for 25 days and MPD for next 5 days; T6: LF for 5 days, then 25% LF replacement by MPD for next 5 days, 50% LF replacement by MPD for next 5 days, 75% LF replacement by MPD for next 5 days, and 100% LF replacement by MPD for last 10 days; and T7: LF for 10 days, then 25% LF replacement by MPD for next 5 days, 50% LF replacement by MPD for next 5 days, 75% LF replacement by MPD for next 5 days, and 100% LF replacement by MPD for last 5 days. Significantly (p < 0.05) higher WG and SGR were recorded in T2 (213.17 ± 0.32, 23.98 ± 0.02) followed by T6, whereas the lowest was found in C2. Significantly higher (p < 0.05) percentage survival was manifested in the T7 (31.83 ± 0.22), followed by T2 (24.75 ± 0.13), and the lowest survival was observed in the C2. The digestive enzyme activities were found to be non-significant (p > 0.05) between different treatment groups. The alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and malate dehydrogenase (MDH) were reported to be significantly higher (p < 0.05) in C2 (68.52 ± 0.08, 19.55 ± 0.10, 21.79 ± 0.04, and 0.044 ± 0.01) followed by T1; however, their reduced level was observed in C1. The activity of superoxide dismutase (SOD), catalase (CAT), glucose, and cortisol levels was observed significantly (p < 0.05) higher in C2 and lower in C1 and T2. As per the finding, it can be recommended that the appropriate weaning time for A. testudineus larvae is from 13 DPH onwards, in which larvae can be fed an initial ten days LF afterward MPD and the best weaning strategy can be adopted as in the T7 group for higher survival percentage.

Hydrolytically degradable hyaluronic acid hydrogels with controlled temporal structures.

Polysaccharides are being processed into biomaterials for numerous biological applications due to their native source in numerous tissues and biological functions. For instance, hyaluronic acid (HA) is found abundantly in the body, interacts with cells through surface receptors, and can regulate cellular behavior (e.g., proliferation, migration). HA was previously modified with reactive groups to form hydrogels that are degraded by hyaluronidases, either added exogenously or produced by cells. However, these hydrogels may be inhibitory and their applications are limited if the appropriate enzymes are not present. Here, for the first time, we synthesized HA macromers and hydrogels that are both hydrolytically (via ester group hydrolysis) and enzymatically degradable. The hydrogel degradation and growth factor release was tailored through the hydrogel cross-linking density (i.e., macromer concentration) and copolymerization with purely enzymatically degradable macromers. When mesenchymal stem cells (MSCs) were encapsulated in the hydrogels, cellular organization and tissue distribution was influenced by the copolymer concentration. Importantly, the distribution of released extracellular matrix molecules (e.g., chondroitin sulfate) was improved with increasing amounts of the hydrolytically degradable component. Overall, this new macromer allows for enhanced control over the structural evolution of the HA hydrogels toward applications as biomaterials.

Graft copolymerization of ethyl acrylate onto cellulose using ceric ammonium nitrate as initiator in aqueous medium.

Ceric ammonium nitrate (CAN) in the presence of nitric acid has been used as efficient initiator for graft copolymerization of the ethyl acrylate onto cellulose at 35.0 +/- 0.1 degrees C. Graft copolymerization of ethyl acrylate onto cellulose has taken place through the radical initiation process. The graft yield and other grafting parameters have been evaluated by varying concentration of ethyl acrylate from 2.5 x 10(-1) to 15.0 x 10(-1) mol dm(-3) and ceric ammonium nitrate from 5.0 x 10(-3) to 25.0 x 10(-3) mol dm(-3) at constant concentration of the nitric acid (8.0 x 10(-2) mol dm(-3)). The rate of graft copolymerization has shown 1.5 order with respect to the concentration of the ceric ammonium nitrate. The graft copolymerization data obtained at different temperatures were used to calculate the energy of activation, which has been found to be 28.9 kJ mol(-1) within the temperature range from 20 to 50 degrees C. The effect of addition of cationic and anionic surfactants on graft copolymerization has also been studied. On the basis of the experimental observations, reaction steps have been proposed and a suitable rate expression for graft copolymerization has been derived.