Establishing an astaxanthin-rich live feed strain of Pseudodiaptomus annandalei.

This study aimed to establish an astaxanthin-rich strain of the calanoid copepod Pseudodiaptomus annandalei, through selective breeding based on RGB (red, green and blue) value, a parameter indicating color intensity. We evaluated the RGB value frequency distributions of the copepod populations, and selected individuals with the highest 10% and the lowest 10% RGB value over six generations. The RGB value, nauplii production, clutch interval and clutch number were assessed, and the genetic gain was calculated across generations (G0-G5). Two strains of copepods were selected and defined as dark body copepod strain (DBS) and light body copepod strain (LBS) at the end of experiment. Results revealed significantly lower RGB values (male: 121.5 ± 14.1; female: 108.8 ± 15) in the G5 DBS population compared to the G0 (male: 163.9 ± 13.1; female: 162.2 ± 14.6), with higher genetic gains of RGB values during G0 to G2. While DBS females exhibited longer clutch intervals in the G3 and G4, there was no significant difference in nauplii production between the two strains across all generations. Significantly higher astaxanthin content was found in the DBS copepods (0.04 µg/ ind.) compared to the LBS copepods (0.01 µg/ ind.) and the non-selective copepods (0.02 µg/ ind.) 20 months post selective breeding, validating the stability of the desired trait in the DBS strain. This study successfully established an astaxanthin-rich strain of P. annandalei, which provides implications for enhancing marine and brackish larviculture production.

Rice (Oryza sativa L.) inhibits growth and induces differentiation of human leukemic U937 cells through activation of peripheral blood mononuclear cells.

Rice (Oryza sativa L.) is a staple food worldwide for centuries. In this study, the growth-inhibiting and immunopotentiating effects of commonly used rice were examined. The growth of human leukemic U937 cells was significantly inhibited by the peripheral blood mononuclear cell-conditioned medium (MNC-CM) derived from water extracts of Japonica rice milled Taiwan 9 (MT9) and brown Taiwan 9 (BT9). Furthermore, these MNC-CMs induced differentiation of U937 cells into mature monocytes/macrophages expressing superoxide-producing and phagocytic activity. The amounts of tumor necrosis factor-alpha and interferon-gamma in MNC-CMs prepared with MT9 and BT9 were greater than normal MNC-CM. However, growth of U937 cells was not inhibited by normal MNC-CM or rice extracts alone. The possible active components of MT9 and BT9, other than PHA-like glycoproteins and heat-sensitive proteins and lipopolysaccharides, remain to be determined. Our results demonstrate that MT9 and BT9 can inhibit growth and induce differentiation of leukemic U937 cells through activation of human peripheral blood MNC in vitro. These two types of rice as energy-providing food could be biological response modifiers for augmenting anti-leukemia immunity.